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Bacterial Counts (bacterial + count)
Kinds of Bacterial Counts Selected AbstractsLow counts of Faecalibacterium prausnitzii in colitis microbiotaINFLAMMATORY BOWEL DISEASES, Issue 8 2009H. Sokol MD Abstract Background: The intestinal microbiota is suspected to play a role in colitis and particularly in inflammatory bowel disease (IBD) pathogenesis. The aim was to compare the fecal microbiota composition of patients with colitis to that of healthy subjects (HS). Methods: fecal samples from 22 active Crohn's disease (A-CD) patients, 10 CD patients in remission (R-CD), 13 active ulcerative colitis (A-UC) patients, 4 UC patients in remission (R-UC), 8 infectious colitis (IC) patients, and 27 HS were analyzed by quantitative real-time polymerase chain reaction (PCR) targeting the 16S rRNA gene. Bacterial counts were transformed to logarithms (Log10 CFU) for statistical analysis. Results: Bacteria of the phylum Firmicutes (Clostridium leptum and Clostridium coccoides groups) were less represented in A-IBD patients (9.7; P = 0.004) and IC (9.4; P = 0.02), compared to HS (10.8). Faecalibacterium prausnitzii species (a major representative of the C. leptum group) had lower counts in A-IBD and IC patients compared to HS (8.8 and 8.3 versus 10.4; P = 0.0004 and P = 0.003). The Firmicutes/Bacteroidetes ratio was lower in A-IBD (1.3; P = 0.0001) and IC patients (0.4; P = 0.002). Compared to HS, Bifidobacteria were less represented in A-IBD and IC (7.9 and 7.7 versus 9.2; P = 0.001 and P = 0.01). Conclusions: The fecal microbiota of patients with IBD differs from that of HS. The phylum Firmicutes and particularly the species F. prausnitzii, are underrepresented in A-IBD patients as well as in IC patients. These bacteria could be crucial to gut homeostasis since lower counts of F. prausnitzii are consistently associated with a reduced protection of the gut mucosa. (Inflamm Bowel Dis 2009) [source] Experimental acute respiratory Burkholderia pseudomallei infection in BALB/c miceINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 1 2009Mark S. Lever Summary Burkholderia pseudomallei is the causative agent of melioidosis, which is considered a potential deliberate release agent. The objective of this study was to establish and characterise a relevant, acute respiratory Burkholderia pseudomallei infection in BALB/c mice. Mice were infected with 100 B. pseudomallei strain BRI bacteria by the aerosol route (approximately 20 median lethal doses). Bacterial counts within lung, liver, spleen, brain, kidney and blood over 5 days were determined and histopathological and immunocytochemical profiles were assessed. Bacterial numbers in the lungs reached approximately 108 cfu/ml at day 5 post-infection. Bacterial numbers in other tissues were lower, reaching between 103 and 105 cfu/ml at day 4. Blood counts remained relatively constant at approximately 1.0 × 102 cfu/ml. Foci of acute inflammation and necrosis were seen within lungs, liver and spleen. These results suggest that the BALB/c mouse is highly susceptible to B. pseudomallei by the aerosol route and represents a relevant model system of acute human melioidosis. [source] Activity of ciprofloxacin and levofloxacin in experimental pneumonia caused by Klebsiella pneumoniae deficient in porins, expressing active efflux and producing QnrA1CLINICAL MICROBIOLOGY AND INFECTION, Issue 7 2008J. M. Rodríguez-Martínez Abstract The objective of this study was to evaluate the activities of ciprofloxacin and levofloxacin in a murine model of pneumonia caused by Klebsiella pneumoniae C2 (with altered GyrA, deficient in porins and expressing active efflux of quinolones) and the transconjugant C2pMG252 derived from it and expressing the qnrA1 determinant. MICs and MBCs of the two quinolones were determined according to CLSI guidelines. Time-kill curves (at 1× and 4× MIC) were also performed to assess bactericidal activity. An experimental model of pneumonia in mice was evaluated. Groups of 15 mice were infected with either strain and treated with ciprofloxacin (80 mg/kg/day) or levofloxacin (100 mg/kg/day). Control non-treated animals were also evaluated. In the case of strain C2, log10 CFU/g of lung in non-treated animals was 9.16 ± 2.16. This value was reduced to 3.53 ± 1.04 (p <0.001) and 3.38 ± 0.46 (p <0.001) in animals treated with ciprofloxacin or levofloxacin, respectively. Percentages of surviving mice were 26.7% (control group) and 100% (both ciprofloxacin and levofloxacin; p <0.001 vs. controls). Bacterial counts (log10 CFU/g) in lungs of animals infected with strain C2pMG252 were 9.65 ± 2.49 in non-treated animals and 7.74 ± 2.67 and 7.57 ± 3.84 for those treated with ciprofloxacin or levofloxacin, respectively (p >0.05 vs. control group). Of non-treated animals infected with strain C2pMG252, 14.3% survived. Ciprofloxacin and levofloxacin improved the survival in these mice (53.3% for both antimicrobials, p 0.03). In conclusion, the expression of qnrA1 in K. pneumoniae with additional mechanisms of resistance causes decreased efficacy of fluoroquinolones in a pneumonia model in mice. [source] Pharmacokinetic/pharmacodynamic assessment of the in-vivo efficacy of imipenem alone or in combination with amikacin for the treatment of experimental multiresistant Acinetobacter baumannii pneumoniaCLINICAL MICROBIOLOGY AND INFECTION, Issue 4 2005M. Bernabeu-Wittel Abstract A guinea-pig pneumonia model involving imipenem-susceptible and imipenem-resistant strains of Acinetobacter baumannii was developed to assess the in-vitro and in-vivo activities of imipenem, alone or in combination with amikacin, and the pharmacokinetic and pharmacodynamic parameters. Serum levels were measured by bioassay (imipenem) or immunoassay (amikacin), followed by calculation of pharmacokinetic and pharmacodynamic parameters (Cmax, AUC, t1/2, Cmax/MIC, AUC/MIC, and ,t/MIC). In-vivo efficacy was evaluated by comparing bacterial counts in the lungs of treatment groups with end-of-therapy controls by anova and post-hoc tests. Decreases in the Cmax (13.4%), AUC (13%), t1/2 (25%) and ,t/MIC (11.8,32.2%) of imipenem were observed when it was administered with amikacin, compared with administration of imipenem alone. Similarly, decreases in the Cmax (34.5%), AUC (11.6%), Cmax/MIC (34.5%) and AUC/MIC (11.7%) of amikacin were observed when it was administered with imipenem. Bacterial counts in lungs were reduced by imipenem (p 0.004) with the imipenem-susceptible strain, and by amikacin (p 0.001) with the imipenem-resistant strain. The combination of imipenem plus amikacin was inferior to imipenem alone with the imipenem-susceptible strain (p 0.01), despite their in-vitro synergy, and was inferior to amikacin alone with the imipenem-resistant strain (p < 0.0001). In summary, combined use of imipenem with amikacin was less efficacious than monotherapy, probably because of a drug,drug interaction that resulted in decreased pharmacokinetic and pharmacodynamic parameters for both antimicrobial agents. [source] Shelf Life and Microbial Quality of Fresh-cut Mango Cubes Stored in High CO2 AtmospheresJOURNAL OF FOOD SCIENCE, Issue 1 2005Jutatip Poubol ABSTRACT: Fresh-cut,Carabao'and,Nam Dokmai'mango cubes were stored in air or in high CO2 atmospheres (3%, 5%, and 10%) at 5 °C and 13 °C. Freshly sliced,Carabao'mango cubes had a lower respiration rate and total bacterial count and higher L-ascorbic acid content and firmness than,Nam Dokmai'mango cubes. The shelf life of fresh-cut mango, based on browning discoloration and water-soaked appearance, was 6 d at 5 °C and 4 d at 13 °C for,Carabao'and 2 d at 5 °C and less than 1 d at 13 °C for,Nam Dokmai'. High CO2 atmospheres retarded the development of water-soaked,Carabao'cubes at 5 °C and 13 °C and,Nam Dokmai'cubes at 5 °C. Texture of,Carabao'cubes was enhanced by high CO2, but ethanol and L-ascorbic acid contents were not affected at 5 °C and 13 °C. Total bacterial count was lower in,Carabao'cubes than in,Nam Dokmai'cubes during storage at both temperatures, and a 10% CO2 only reduced the bacterial count on,Carabao'and,Nam Dokmai'cubes stored at 13 °C. Bacterial flora in,Nam Dokmai'mango cubes consisted mostly of Gram-negative rods assigned primarily to phytopathogenic bacteria such as Pantoea agglomerans and Burkholderia cepacia. The genera of bacteria isolated from cubes stored in 10% CO2 were similar to those from cubes on the initial day. [source] Development of Biogenic Amines in Yellowfin Tuna (Thunnus albacares): Effect of Storage and Correlation with Decarboxylase-Positive Bacterial FloraJOURNAL OF FOOD SCIENCE, Issue 1 2002W.-X. Du ABSTRACT: The effects of storage at 0,4,10, and 22°C for 0,1,3,5, and 9 d on the quality of yellowfin tuna fillets as determined by microbiological assessment, development of some biogenic amines, and sensory analysis were studied. Tuna fillets stored at 22 °C for 3 d, 10 °C for 5 d, and 4 °C for 9 d were rated unacceptable for consumption. Those stored at 22 °C for 3 d had total aerobic bacterial count of > 8 log10 CFU/g, a histamine-producing bacterial population of 7 log10 CFU/g, and 832 ppm of histamine, 35.8 ppm of putrescine, and 147 ppm of cadaverine. A comparison of the capillary electrophoresis, AOAC fluorometric method, and gas chromatography showed a very good correlation (r2 > 0.99) among these 3 methods for histamine quantitation in tuna samples. Morganella morganii, Enterobacter agglomerans, Enterobacter intermedium, Pseudomonas fluorescens, Proteins vulgaris, and Serratia liquefaciens were the decarboxylase-positive bacterial species isolated by using the Niven's medium and identified during storage, which were responsible for histamine production in test tuna fillets. [source] Extract of Juglandaceae regia Inhibits Growth, In-vitro Adherence, Acid Production and Aggregation of Streptococcus mutansJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 2 2000A. G. JAGTAP Aqueous and alcoholic extracts from Juglandaceae regia, used as chewing sticks to maintain oral hygiene, were tested for their ability to inhibit the growth and some physiological functions of Streptococcus mutans. Both the aqueous and the alcoholic extract strongly inhibited the growth, in-vitro adherence, acid production and glucan-induced aggregation of S. mutans. At a concentration of 8% w/v, the aqueous extract produced a 95% inhibition (P < 0.05) of adherence of S. mutans to glass and a 40% inhibition (P < 0.05) of adherence to tooth surface. The alcoholic extract at a concentration of 10% w/v produced a 95% inhibition (P < 0.05) of adherence of S. mutans to glass and a 56% inhibition (P < 0.05) of adherence to tooth surface. At concentrations of 2% w/v the aqueous and alcoholic extracts significantly inhibited (P < 0.05) glucan-induced aggregation of S. mutans and the in-vitro salivary glycolytic reaction for up to 5 h. Bactericidal effects on S. mutans were also evident. At a concentration of 10% w/v, the zone of inhibition observed with the aqueous extract was 12 ± 0.01 mm and that observed with the alcoholic extract was 12.6 ± 0.02 mm. As the in-vitro studies had shown that both the aqueous and the alcoholic extract of J. regia, at concentrations of 10% w/v, could inhibit the growth as well as the acid-producing ability of S. mutans, they were tested at the same concentration for their activity in-vivo. Three subjects were employed. Parameters monitored were salivary bacterial count and salivary glycolysis. Mouth-rinsing with the aqueous but not the alcoholic extract significantly reduced total streptococcal counts in the salivary samples obtained up to, and including, 3 h after rinsing, compared with the counts obtained pre-rinsing or after placebo rinsing. Mouth-rinsing with the aqueous extract produced a 65%, 27% and 78% reduction (P < 0.05) in the streptococcal count in the salivary samples obtained 10 min, 1 h and 3 h after rinsing, respectively. Both the aqueous and the alcoholic extract also inhibited the glycolytic reaction by the salivary bacteria for up to 90 min post-rinsing. This study provides evidence to justify the use of J. regia sticks as an aid to maintain oral hygiene. [source] Sterilization of ginseng using a high pressure CO2 at moderate temperaturesBIOTECHNOLOGY & BIOENGINEERING, Issue 2 2009Fariba Dehghani Abstract The aim of this study was to determine the feasibility of using high pressure CO2 for sterilization of Ginseng powder, as an alternative method to conventional techniques such as ,-irradiation and ethylene oxide. The Ginseng sample used in this study was originally contaminated with fungi and 5,×,107 bacteria/g that was not suitable for oral use. This is the first time that high pressure CO2 has been used for the sterilization of herbal medicine to decrease the total aerobic microbial count (TAMC) and fungi. The effect of the process duration, operating pressure, temperature, and amount of additives on the sterilization efficiency of high pressure CO2 were investigated. The process duration was varied over 15 h; the pressure between 100 and 200 bar and the temperature between 25 and 75°C. A 2.67-log reduction of bacteria in the Ginseng sample was achieved after long treatment time of 15 h at 60°C and 100 bar, when using neat carbon dioxide. However, the addition of a small quantity of water/ethanol/H2O2 mixture, as low as 0.02 mL of each additive/g Ginseng powder, was sufficient for complete inactivation of fungi within 6 h at 60°C and 100 bar. At these conditions the bacterial count was decreased from 5,×,107 to 2.0,×,103 TAMC/g complying with the TGA standard for orally ingested products. A 4.3 log reduction in bacteria was achieved at 150 bar and 30°C, decreasing the TAMC in Ginseng sample to 2,000, below the allowable limit. However, fungi still remained in the sample. The complete inactivation of both bacteria and fungi was achieved within 2 h at 30°C and 170 bar using 0.1 mL of each additive/g Ginseng. Microbial inactivation at this low temperature opens an avenue for the sterilization of many thermally labile pharmaceutical and food products that may involve sensitive compounds to ,-radiation and chemically reactive antiseptic agents. Biotechnol. Bioeng. 2009;102: 569,576. © 2008 Wiley Periodicals, Inc. [source] Decreased incidence of ventilator-associated pneumonia caused by Pseudomonas aeruginosa over 3 yearsBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 7 2000M. Fiore Background Ventilator-associated pneumonia (VAP) is a frequently occurring infection among critically ill patients. Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae and Escherichia coli are the most common micro-organisms causing VAP. The aim of this study was to ascertain the incidence of VAP diagnosed with bronchoalveolar lavage (BAL) by these possible pathogenic micro-organisms (PPMOs). Because VAP is often preceded by colonization of the oropharynx with the causative pathogen, sputum cultures were compared with the BAL cultures. Methods Over a 3-year period, all ventilated patients in two intensive care units (n = 1136) were reviewed for pneumonia. A VAP was present when the bacterial count of the BAL was more than 104 colony-forming units ml,1. The microbial results of all patients with a VAP (polymicrobial or monomicrobial) were recorded. Results The mean incidence of VAP was 8 per cent (n = 92), decreasing only slightly during the period (P > 0·05). The most frequent aetiological agents were P. aeruginosa (n = 34), S. aureus (n = 22), E. coli (n = 16) and K. pneumoniae (n = 10). The percentage of VAPs due to P. aeruginosa has declined progressively from 53 to 31 per cent. Concurrently, the incidence of Pseudomonas colonizing the sputum culture has declined (from 54 to 44 per cent). On the other hand, the incidence of VAP due to E. coli has increased from 13 (n = 2) to 36 per cent (n = 6). Colonization of the sputum with E. coli has similarly increased (from 13 to 27 per cent). Conclusion The incidence of VAP in the intensive care unit is in accordance with the literature, when diagnosed with strict criteria. No significant change in the incidence of VAP was noted during the 3-year period. Neither the decrease in incidence of VAP caused by P. aeruginosa nor the increase in E. coli pneumonia can be explained by a change in antibiotic regimens in the period studied. Hypothetically, cross-colonization of PPMOs by healthcare personnel can be influenced by hand-washing and wearing gloves. This can especially influence colonization by P. aeruginosa, thus explaining the decrease. © 2000 British Journal of Surgery Society Ltd [source] Folic acid supplementation on red kidney bean-induced diarrhoea and enteric bacterial translocation into mesenteric lymph nodes in rats: a pilot studyACTA PAEDIATRICA, Issue 1 2002R Shoda Deaths following childhood diarrhoea, a major health problem in developing countries, are often associated with malnutrition and septicaemic complications. Folic acid has been used in the treatment of acute and chronic diarrhoea in the tropics. Using a rat model, we evaluated the protective effect of large doses of folic acid on diarrhoea, small intestinal bacterial overgrowth and translocation of enteric bacteria into mesenteric lymph nodes induced by a raw red kidney bean-based diet containing lectin (phytohemagglutinin). Long-Evans rats in 2 groups of 5 each (60 g to 70 g in weight, 28 d old) were used. All 10 rats, individually kept in metabolic cages, received a raw red kidney bean-based diet for 10 d, and 5 of them also received a daily folic acid supplement (160 ,g/g feed) both during and for 10 d before the experiment. The faecal weight was measured and a quantitative aerobic bacterial culture of the small intestinal mucosal scrapings and of the mesenteric lymph nodes was made. Folic acid supplementation did not reduce faecal output nor did it prevent loss of body weight associated with lectin-induced diarrhoea. However, the mean total count of enteric bacteria translocated to the mesenteric lymph nodes was significantly reduced in the supplemented rats (1.27 ± 0.61 vs 2.66 ± 0.84, p= 0.028) and a trend towards reduced bacterial count in the small intestinal mucosal scrapings (0.40 ± 0.89 vs 1.42 ± 1.31, p= 0.16) was documented. A significant positive correlation was also seen between the bacterial count in the jejunal mucosal scrapings and in the mesenteric lymph nodes. Conclusion: Although large-dose folic acid supplementation did not prevent diarrhoea and malnutrition induced by a lectin-based diet, it substantially reduced the count of enteric bacteria translocated into the mesenteric lymph nodes and showed a trend towards a reduction in indigenous bacteria adhering to jejunal mucosa. These findings could be of relevance in the prevention of septicaemic complications following many clinical conditions, including diarrhoea with malnutrition in children known to have bacteraemic and septicaemic complications. [source] Environmental determinants correlated to Vibrio harveyi -mediated death of marine gastropodsENVIRONMENTAL MICROBIOLOGY, Issue 1 2010Youhei Fukui Summary Vibrio harveyi is an emerging pathogen that causes mass mortality in a wide variety of marine animal species; however, it is still unclear which environmental determinants correlate V. harveyi dynamics and the bacterium-mediated death of marine animal life. We conducted a correlation analysis over a 5-year period (2003,2007) analysing the following data: V. harveyi abundance, marine animal mortality and environmental variables (seawater temperature, salinity, pH, chlorophyll a, rainfall and total viable bacterial counts). The samples were collected from a coastal area in northern Japan, where deaths of a marine gastropod species (Haliotis discus hannai) have been reported. Our analysis revealed significant positive correlations between average seawater temperature and average V. harveyi abundance (R = 0.955; P < 0.05), and between average seawater temperature and V. harveyi -mediated abalone death (R = 0.931; P < 0.05). Based on the regression model, n°C rise in seawater temperature gave rise to a 21n -fold increase in the risk of mortality caused by V. harveyi infection. This is the first report providing evidence of the strong positive correlation between seawater temperature and V. harveyi -mediated death of marine species. [source] Dominant sugar utilizers in sediment of Lake Constance depend on syntrophic cooperation with methanogenic partner organismsENVIRONMENTAL MICROBIOLOGY, Issue 6 2008Nicolai Müller Summary Six strains of novel bacteria were isolated from profundal sediment of Lake Constance, a deep freshwater lake in Germany, by direct dilution of the sediment in mineral agar medium containing a background lawn of the hydrogen-scavenging Methanospirillum hungatei as a syntrophic partner. The numbers of colony-forming units obtained after incubation for more than 2 months were in the same range as those of total bacterial counts determined by DAPI staining (up to 108 cells per millilitre) suggesting that these organisms were dominant members of the community. Identical dilution series in the absence of methanogenic partners yielded numbers that were lower by two to three orders of magnitude. The dominant bacteria were isolated in defined co-culture with M. hungatei, and were further characterized. Growth was slow, with doubling times of 22,28 h at 28°C. Cells were small, 0.5 × 5 ,m in size, Gram-positive, and formed terminal oval spores. At 20°C, glucose was fermented by the co-culture strain BoGlc83 nearly stoichiometrically to 2 mol of acetate and 1 mol of methane plus CO2. At higher temperatures, also lactate and traces of succinate were formed. Anaerobic growth depended strictly on the presence of a hydrogen-scavenging partner organism and was inhibited by bromoethane sulfonate, which together indicate the need for a syntrophic partnership for this process. Strain BoGlc83 grew also aerobically in the absence of a partner organism. All enzymes involved in ATP formation via glycolysis and acetyl CoA were found, most of them at activities equivalent to the physiological substrate turnover rate. This new type of sugar-fermenting bacterium appears be the predominant sugar utilizer in this environment. The results show that syntrophic relationships can play an important role also for the utilization of substrates which otherwise can be degraded in pure culture. [source] Bacteria associated with the rapid tissue necrosis of stony coralsENVIRONMENTAL MICROBIOLOGY, Issue 7 2007G. M. Luna Summary The rapid tissue necrosis (RTN) is a common disease of both wild and captive stony corals, which causes a fast tissue degradation (peeling) and death of the colony. Here we report the results of an investigation carried out on the stony coral Pocillopora damicornis, affected by an RTN-like disease. Total abundance of prokaryotes in tissue samples, determined by epifluorescence microscopy, was significantly higher in diseased than in healthy corals, as well as bacterial counts on MB2216 agar plates. Further experiments performed by fluorescent in situ hybridization using a 16S rDNA Vibrio -specific probe showed that vibrios were significantly more abundant in diseased than in healthy corals. Accordingly, bacterial counts on TCBS agar plates were higher in diseased than in healthy tissues. 16S rDNA sequencing identified as Vibrio colonies from diseased tissues only. Cultivated vibrios were dominated by a single ribotype, which displayed 99% of similarity with Vibrio harveyi strain LB4. Bacterial ribotype richness, assessed by terminal-restriction fragment length polymorphism analysis of the 16S rDNA, was significantly higher in diseased than in healthy corals. Using an in silico software, we estimated that a single terminal restriction fragment, putatively assigned to a Vibrio sp., accounted for >,15% and < 5% of the total bacterial assemblage, in diseased and healthy corals respectively. These results let us hypothesize that the RTN in stony corals can be an infectious disease associated to the presence of Vibrio harveyi. However, further studies are needed to validate the microbial origin of this pathology. [source] The effect of cleaning and disinfecting the sampling well on the microbial communities of deep subsurface water samplesENVIRONMENTAL MICROBIOLOGY, Issue 1 2005Odile Basso Summary Our knowledge of the microbial characteristics of deep subsurface waters is currently very limited, mainly because of the methods used to collect representative microbial samples from such environments. In order to improve this procedure, a protocol designed to remove the unspecific, contaminant biofilm present on the walls of an approximately 800 m deep well is proposed. This procedure included extensive purges of the well, a mechanical cleaning of its wall, and three successive chlorine injections to disinfect the whole line before sampling. Total bacterial counts in water samples decreased from 2.5 × 105 to 1.0 × 104 per millilitre during the cleaning procedure. Culture experiments showed that the first samples were dominated by sulfate-reducers and heterotrophs, whereas the final sample was dominated by oligotrophic and hydrogenotrophic bacteria. Community structures established on the diversity of the 16S rRNA genes and data analysis revealed that the water sample collected, after a purge without removal of the biofilm, was characterized by numerous phyla which are not representative of the deep subsurface water. On the other hand, several bacterial phyla were only detected after the full cleaning of the well, and were considered as important components of the subsurface ecosystem which would have been missed in the absence of well cleaning. [source] Determination of aerial microbiological contamination in scholastic sports environmentsJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2003C. Dacarro Abstract Aims: To assess the microbiological indoor air quality (IAQ) of high school and college gyms during physical training lessons and to evaluate the effective microbiological exposure of students. Methods and Results: Air samples from 11 high school and college gyms of Pavia, Italy were collected. Total bacterial counts, total fungal counts and characterization of fungal taxa were determined. Air quality was evaluated using three microbiological contamination indices: the global index of microbiological contamination per m3 (GIMC per m3), the index of mesophilic bacterial contamination (IMC) and the amplification index (AI). Conclusions: This work testifies that air contamination in indoor gyms is always superior to that of the outdoor environment. Nevertheless, students are exposed to relatively low concentrations of airborne micro-organisms. The highest values of fungal counts and GIMC per m3 (>14 661) were observed between April and October when the central heating systems were switched off. The lowest fungal counts were detected in modern buildings equipped with forced ventilation systems. From qualitative aeromycological studies, 45 fungal taxa were identified, and different potentially allergenic species were isolated. Significance and Impact of the Study: The standardization of air sampling methods and the correct evaluation of aeromicrobiological results allow the classification of indoor air healthiness. The proposed microbiological contamination indices together with the characterization of airborne fungal taxa are useful tools for detailed description of IAQ. [source] Antibacterial activity of dental composites containing zinc oxide nanoparticles,JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2010Berdan Aydin Sevinç Abstract The resin-based dental composites commonly used in restorations result in more plaque accumulation than other materials. Bacterial biofilm growth contributes to secondary caries and failure of resin-based dental composites. Methods to inhibit biofilm growth on dental composites have been sought for several decades. It is demonstrated here that zinc oxide nanoparticles (ZnO-NPs) blended at 10% (w/w) fraction into dental composites display antimicrobial activity and reduce growth of bacterial biofilms by roughly 80% for a single-species model dental biofilm. Antibacterial effectiveness of ZnO-NPs was assessed against Streptococcus sobrinus ATCC 27352 grown both planktonically and as biofilms on composites. Direct contact inhibition was observed by scanning electron microscopy and confocal laser scanning microscopy while biofilm formation was quantified by viable counts. An 80% reduction in bacterial counts was observed with 10% ZnO-NP-containing composites compared with their unmodified counterpart, indicating a statistically significant suppression of biofilm growth. Although, 20% of the bacterial population survived and could form a biofilm layer again, 10% ZnO-NP-containing composites maintained at least some inhibitory activity even after the third generation of biofilm growth. Microscopy demonstrated continuous biofilm formation for unmodified composites after 1-day growth, but only sparsely distributed biofilms formed on 10% ZnO-NP-containing composites. The minimum inhibitory concentration of ZnO-NPs suspended in S. sobrinus planktonic culture was 50 ,g mL,1. ZnO-NP-containing composites (10%) qualitatively showed less biofilm after 1-day-anaerobic growth of a three-species initial colonizer biofilm after being compared with unmodified composites, but did not significantly reduce growth after 3 days. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010. [source] Mechanical non-surgical treatment of peri-implantitis: a double-blind randomized longitudinal clinical study.JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 7 2009I: clinical results Abstract Background: Peri-implantitis is a frequent finding in patients with dental implants. The present study compared two non-surgical mechanical debridement methods of peri-implantitis. Material and Methods: Thirty-seven subjects (mean age 61.5; S.D±12.4), with one implant each, demonstrating peri-implantitis were randomized, and those treated either with titanium hand-instruments or with an ultrasonic device were enrolled. Data were obtained before treatment, and at 1, 3, and 6 months. Parametric and non-parametric statistics were used. Results: Thirty-one subjects completed the study. The mean bone loss at implants in both groups was 1.5 mm (SD ±1.2 mm). No group differences for plaque or gingival indices were found at any time point. Baseline and 6-month mean probing pocket depths (PPD) at implants were 5.1 and 4.9 mm (p=0.30) in both groups. Plaque scores at treated implants decreased from 73% to 53% (p<0.01). Bleeding scores also decreased (p<0.01), with no group differences. No differences in the total bacterial counts were found over time. Higher total bacterial counts were found immediately after treatment (p<0.01) and at 1 week for ultrasonic-treated implants (p<0.05). Conclusions: No group differences were found in the treatment outcomes. While plaque and bleeding scores improved, no effects on PPD were identified. [source] Microbial colonization patterns predict the outcomes of surgical treatment of intrabony defectsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 1 2006Lisa Heitz-Mayfield Abstract Aim: To explore the impact of bacterial load and microbial colonization patterns on the clinical outcomes of periodontal surgery at deep intrabony defects. Materials and Methods: One hundred and twenty-two patients with advanced chronic periodontitis and at least one intrabony defect of >3 mm were recruited in 10 centres. Before recruitment, the infection control phase of periodontal therapy was completed. After surgical access and debridement, the regenerative material was applied in the test subjects, and omitted in the controls. At baseline and 1 year following the interventions, clinical attachment levels (CAL), pocket probing depths (PPD), recession (REC), full-mouth plaque scores and full-mouth bleeding scores were assessed. Microbial colonization of the defect-associated pocket was assessed using a DNA,DNA checkerboard analysis. Results: Total bacterial load and counts of red complex bacteria were negatively associated with CAL gains 1 year following treatment. The probability of achieving above median CAL gains (>3 mm) was significantly decreased by higher total bacterial counts, higher red complex and T. forsythensis counts immediately before surgery. Conclusions: Presence of high bacterial load and specific periodontal pathogen complexes in deep periodontal pockets associated with intrabony defects had a significant negative impact on the 1 year outcome of surgical/regenerative treatment. [source] Five-year maintenance follow-up of early-onset periodontitis patientsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 6 2003Joanna J. Kamma Abstract Objectives: The purpose of this study was to evaluate the clinical and microbiological status of patients with early-onset or aggressive periodontitis (EOP) who had received supportive periodontal care (SPC) every 3,6 months for a period of 5 years, following active periodontal treatment. Material & Methods: The study population consisted of 25 individuals with early-onset periodontitis. Clinical examination and recordings of probing pocket depth (PPD) and clinical attachment level (CAL) were performed at baseline prior to treatment (T0), 3 months following the termination of active periodontal treatment (T1) and annually at the SPC appointments (T2,T3,T4,T5). Microbiological samples were obtained at the 5-year SPC (T5). Subgingival plaque samples for each individual were collected from one deep pocket (>5 mm), based on pretreatment measurements, randomly selected in each quadrant. The levels of Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Porphyromonas gingivalis and Treponema denticola were determined using oligonucleotide probe hybridization. Results: During the 5-year period, the mean of SPC/patient was 12.7 sessions. A significant improvement was observed in PPD, CAL, gingival bleeding index and suppuration following treatment. However, between T1 and T5, 134 sites in 20 patients deteriorated with a CAL loss of,2 mm. Out of these 134 sites showing disease progression, microbial samples were randomly obtained in 13 sites (9.7%) from 8 patients. Among other factors, smoking and stress were found to have significant predictive value on the future attachment loss. P. gingivalis, T. denticola and total bacterial load were statistically significantly higher in patients who experienced disease progression during the 5-year maintenance period. Conclusions: For most EOP patients, regular SPC was effective in maintaining clinical and microbiological improvements attained after active periodontal therapy. However, a small percentage of sites was identified as progressive in 20 patients. Variables found to be related to periodontal progression were the presence of as well as the high bacterial counts of P. gingivalis, T. denticola and total bacterial load, number of acute episodes, number of teeth lost, smoking and stress. Zusammenfassung Erhaltungstherapie über fünf Jahre bei Patienten mit früh einsetzender Parodontitis (EOP) Ziele: Der Zweck dieser Studie war es, 5 Jahre nach aktiver Parodontalbehandlung den klinischen und mikrobiologischen Zustand von Patienten mit früh einsetzender oder aggressiver Parodontitis (EOP), bei welchen alle 3-6 Monate eine parodontale Erhaltungstherapie (SPC) erfolgte, zu evaluieren. Material & Methoden: Die Studienpopulation bestand aus 25 Individuen mit früh einsetzender Parodontitis. Die klinische Untersuchung und Aufzeichnung der Sondierungstiefe (PPD) sowie des klinischen Attachmentniveaus (CAL) erfolgten bei der Eingangsuntersuchung vor der Behandlung (T0), drei Monate nach Beendigung der aktiven Parodontalbehandlung (T1) und jährlich bei den SPC-Terminen (T2,T3,T4,T5). Die mikrobiologischen Proben wurden bei der 5-Jahres-SPC gewonnen (T5). Für jedes Individuum wurden die subgingivalen Plaqueproben in jedem Quadranten aus einer tiefen Tasche (>5mm) entnommen. Dies geschah randomisiert und auf der Grundlage der Messungen vor der Behandlung. Das Niveau von Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Porphyromonas gingivalis und Treponema denticola wurden unter Verwendung der Hybridisierung mit Oligonukleotid-Sonden bestimmt. Ergebnisse: Während der 5-jährigen Periode betrug die mittlere Anzahl der SPC-Sitzungen pro Patient 12,7. Nach der Behandlung wurden bei PPD, CAL, Gingiva-Blutungs-Index und der Pusentleerung signifikante Verbesserungen beobachtet. Jedoch haben sich zwischen T1 und T5 bei 20 Patienten 134 Taschen mit einem CAL-Verlust von=2mm verschlechtert. Bei 8 Patienten wurden aus diesen 134 Taschen, mit Progression der Erkrankung, von 13 Taschen (9,7%) randomisiert mikrobiologische Proben entnommen. Innerhalb anderer Faktoren wurde bei Rauchen und Stress ein signifikanter Vorhersagewert für zukünftigen Attachmentverlust vorgefunden. Bei den Patienten, die in der 5-jährigen Erhaltungsperiode eine Progression der Erkrankung erfuhren lagen P. gingivalis, T. denticola und die bakterielle Gesamtbelastung höher. Schlussfolgerungen: Für die meisten EOP-Patienten die regelmäßig an der parodontalen Erhaltungstherapie teilnahmen war diese hinsichtlich der Aufrechterhaltung der nach der aktiven Parodontaltherapie erzielten klinischen und mikrobiologischen Verbesserungen erfolgreich. Jedoch wurde bei 20 Patienten ein geringer Prozentsatz von Taschen als fortschreitend identifiziert. Die Variablen, von denen gefunden wurde, dass sie eine Beziehung zur Progression haben waren: sowohl Vorhandensein von P. gingivalis, T. denticola als auch hohe Bakterienzahl von P. gingivalis, T. denticola und die bakterielle Gesamtbelastung, Anzahl der akuten Episoden, Anzahl verlorener Zähne, Rauchen und Stress. Résumé Suivi en maintenance sur 5 ans de patients atteints de parodontites d'apparition précoce. Objectifs: Cette étude se propose d'évaluer l'état clinique et microbiologique de patients atteints de parodontites d'apparition précoce ou agressive (EOP) qui furent suivis en maintenance (SPC) tous les 3-6 mois pendant une période de 5 ans après un traitement parodontal actif. Matériel & Méthodes: La population étudiée consistait en 25 individus atteints de parodontites d'apparition précoce. L'examen clinique et l'enregistrement des profondeurs de poche (PPD) et du niveau d'attache (CAL) furent réalisés avant le traitement (T0), 3 mois après la fin du traitement actif (T1) et chaque année aux rendez vous de maintenance (T2,T3,T4,T5). Des échantillons microbiologiques furent prélevés lors de la maintenance à 5 ans (T5). La plaque sous-gingivale de chaque patient fut prélevée d'une poche profonde (>5mm), sur la base des examens initiaux, choisis au hasard dans chaque quadrant. Les niveaux d' Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Porphyromonas gingivalis et Treponema denticola furent déterminés par hybridation par sonde d'oligonucleotides. Résultats: pendant la période d'examination de 5 ans, la moyenne des SPC par patient fut de 12.7 sessions. Une amélioration significative fut observée pour PPD, CAL, l'indice de saignement gingival et la suppuration suite au traitement. Cependant, entre T1 et T5, 134 sites chez 20 patients connurent une détérioration avec une perte d'attache de 2 mm. De ces 134 sites qui présentaient une progression de la maladie, des échantillons microbiologiques furent obtenus aléatoirement dans 13 sites (9.7%) chez 8 patients. Parmi d'autres facteurs, le tabagisme et le stress furent reconnus comme ayant une significative valeur prédictive pour de futures pertes d'attache. P. gingivalis, T. denticola et la charge bactérienne totale étaient de façon statistiquement significatif plus importants chez les patients chez qui la maladie progressait au cours des 5 ans de maintenance. Conclusions: pour la plupart des patients atteints d' EOP, des soins parodontaux de soutien réguliers sont efficaces pour maintenir les améliorations cliniques et microbiologiques obtenus par le traitement actif. Cependant, un petit pourcentage de sites progressait chez 20 patients. Les variables en ralation avec cette progression étaient la présence et aussi un comptage important de P. gingivalis, T. denticola et la charge bactérienne totale, le nombre d'épisodes aigus le nombre de dents perdues le tabagisme et le stress. [source] Tongue coating and salivary bacterial counts in healthy/gingivitis subjects and periodontitis patientsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 10 2001S. Mantilla Gómez Abstract Background: The papillary structure of the dorsum of the tongue forms a unique ecological site that provides a large surface area favoring the accumulation of oral debris and microorganisms. These micro-organisms of the tongue may be of influence on the flora of the entire oral cavity. The normal appearance of the dorsum of the tongue is either pinkish or has a thin white coating. For the present study a scoring method was developed to describe the appearance of the dorsum of the tongue in relation to the extent of color and thickness of tongue coating. Aim: The purpose of this study was to investigate the discoloration and coating of the tongue in healthy/gingivitis subjects and periodontitis patients. Furthermore, to determine the relationship between the appearance of the tongue and the bacterial load in salivary samples. Material and Methods: 2 groups of patients were studied, 70 healthy/gingivitis subjects and 56 periodontitis patients. After scoring of the tongue a salivary sample of each patient was taken and analyzed using a phase-contrast microscope. Results: This investigation showed that most discoloration was found on the distal part of the tongue. The mean number of bacteria per ml sample in relation to a pink, white and yellow appearance of the tongue was 948, 855 and 900 (×106) respectively. The mean number of bacteria per ml sample in relation to no, thin and thick coating was 948, 863, and 895 (×106), respectively. Analysis did not reveal a relationship between discoloration, coating thickness and total bacterial load. The mean number of bacteria per ml in healthy/gingivitis subjects was 860 and in periodontitis patients 918 (×106). Conclusion: No relationship between the appearance of the tongue and salivary bacterial load could be detected. There was no difference in bacterial load between the healthy/gingivitis and the periodontitis group within the present study population. Zusammenfassung Hintergrund: Die papilläre Struktur des Zungenrückens bildet eine einheitliche ökologische Oberfläche, die eine große Oberfläche vermittelt, was die Akkumulation von oralem Belag und Mikroorganismen favorisiert. Diese Mikroorganismen der Zunge können die Flora der gesamten Mundhöhle beeinflussen. Die normale Erscheinung des Zungenrückens ist eher pinkfarben oder hat einen dünnen, weißen Belag. Für die vorliegende Studie wurde eine Meßmethode entwickelt, um die Erscheinung des Zungenrückens in Beziehung zum Ausmaß der Farbe und der Dicke des Zungenbelags zu beschrieben. Ziel: Der Zweck der Studie war die Untersuchung der Verfärbung und der Belagbildung auf der Zunge bei gesunden bzw. Gingivitis-Personen und Parodontitis-Patienten. Weiterhin sollte die Beziehung zwischen der Erscheinung der Zunge und dem bakteirellen Gehalt in Speichelproben bestimmt werden. Material und Methoden: 2 Gruppen von Patienten wurden untersucht, 70 gesunde bzw. Gingivitis-personen und 56 Parodontitis-Patienten. Nach der Beurteilung der Zunge wurde von jedem Patienten eine Speichelprobe genommen und mit einem Phasenkontrastmikroskop untersucht. Ergebnisse: Die Ergebnisse zeigten, daß die meiste Verfärbung der Zunge am distalen Teil gefunden wurde. Die mittlere Anzahl der Bakterien pro ml Speichel in Beziehung zu einer pinkfarbigen, weißen und gelben Erscheinung der Zunge was 948, 855 oder 900 (×106). Die mittlere Anzahl der Bakterien pro ml Speichel in Beziehung zu keinem, zu dünnem oder zu dickem Belag war 948, 863 oder 895 (×106). Die Analyse zeigte keine Beziehung zwischen Verfärbung, Belagsdicke und totalem Bakteriengehalt. Die mittlere Anzahl von Bakterien pro ml bei gesunden bzw. Gingivitis-Personen war 860 und bei Parodontitis-Patienten 918 (×106). Zusammenfassung: Es konnte kein Beziehung zwischen der Erscheinung der Zunge und dem bakteriellen Gehalt entdeckt werden. Es gab keine Differenzen im bakteriellen Gehalt zwischen den gesunden bzw. Gingivitis-Personen und den Parodontitis-Patienten innerhalb der vorliegenden Studienpopulation. Résumé Origine: La structure papillaire du dos de la langue forme un site écologique unique qui comporte une large surface favorisant l'accumulation de débris buccaux et de micro-organismes. Ces derniers peuvent avoir une influence sur la flore de l'ensemble de la cavité buccale. L'apparence normale du dos de la langue est rosée ou possède un très fin recouvrement blanc. Une méthode d'échellonnage a été développée afin de décrire l'apparence du dos de la langue en relation avec l'ampleur de la couleur et l'épaisseur du recouvrement de la langue. But: Le but de cette étude a été d'étudier la décoloration et le recouvrement de la langue chez des sujets sains/avec gingivite et parodontite. De plus la relation entre l'apparence de la langue et la charge bactérienne dans les échantillons salivaires a été déterminée. Matériaux et méthodes: 2 groupes de patients ont étéétudiés, 70 sujets sains ou avec gingivite et 56 patients avec parodontite. Après avoir évalué la langue, un échantillon salivaire de chaque patient a été prélevé et analysé en utilisant un microscope à contraste de phase. Résultats: Les résultats ont montré que la plupart de la décoloration était trouvée dans la partie distale de la langue. Le nombre moyen de bactéries par ml d'échantillon en relation avec la couleur rose, blanche ou jaune était respectivement de 948, 855 et 900 (×106). Le nombre moyen de bactéries par ml d'échantillon en relation avec un recouvrement inexistant, fin ou épais était respectivement de 948, 863 et 895 (×106). L'analyse n'a pas mis en évidence une relation entre la décoloration, l'épaisseur de recouvrement et la charge bactérienne totale. Le nombre moyen de bactéries par ml chez des sujets sains/gingivite était de 860 et chez les patients avec parodontite de 918 (×106). Conclusion: Aucune relation entre l'apparence de la langue et la charge bactérienne salivaire n'a donc pûêtre détectée. Il n'y avait aucune différence dans la charge bactérienne entre le groupe sain/gingivite et le groupe parodontite dans la population étudiée. [source] ANTIOXIDATIVE AND ANTIMICROBIAL PROPERTIES OF LACTOFERRIN IN HOT-BONED GROUND PORK DURING STORAGEJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2 2007C.H. CHIU ABSTRACT The effect of lactoferrin concentration on the antioxidative and antimicrobial activities of hot-boned (4,5 h after death) ground pork during storage at 4C for 9 days was examined. The total iron content increased with the addition of lactoferrin. Meat samples with added lactoferrin (40 or 80 mg/kg) had lower thiobarbituric acid reactive substances (TBARS) than controls at 3, 6 and 9 days; however, the differences in TBARS between the 40- and 80-mg lactoferrin/kg treatments were not significant. With the addition of lactoferrin (40 or 80 mg/kg), ground pork had lower (P < 0.05) total plate counts than controls at 3, 6 and 9 days of storage. However, the differences in total plate counts between the 40- and 80-mg lactoferrin/kg treatments were only significant (P < 0.05) at days 3 and 6. The addition of lactoferrin (80 mg/kg) decreased lactic acid bacterial counts at days 0, 3 and 9. The pH values of hot-boned ground pork were unaffected by the addition of lactoferrin, but slightly increased with storage time. [source] QUALITY OF FROZEN SHRIMP THAWED BY RECIRCULATING AIR VERSUS WATER IMMERSIONJOURNAL OF FOOD QUALITY, Issue 1 2003C. S. LIN ABSTRACT The quality of shrimp thawed using a constant temperature thawing chamber compared with running water was studied. Shrimp thawed in room temperature air was used as the control. Shrimp thawed using the thawing chamber had lower drip loss, higher yield and moisture content than shrimp thawed by running water. However, the differences were not statistically significant. There were also no significant differences in press juice and shear force between control and shrimp thawed using either thawing method. Shrimp thawed using the thawing chamber had lower aerobic bacterial counts than either control or shrimp thawed using running water. Shrimp thawed using the thawing chamber did not exceed ,1C throughout the thawing experiment, and microbial growth during thawing was also avoided. Results indicated that the thawing chamber has potential for the foodservice industry to produce uniformly thawed products under sanitary conditions. [source] ISOLATION AND CHARACTERIZATION OF BACTERIOCIN-PRODUCING MICROORGANISMS FROM AGOS-OSJOURNAL OF FOOD SAFETY, Issue 3 2000JULIE D. TAN ABSTRACT Agos-os, a fermented meat and sweetpotato mixture, was produced and analyzed for its microbial characteristics. pH decreased during fermentation. Mold and anaerobic bacterial counts increased while yeasts and aerobic bacterial counts decreased during the third and seventh day of fermentation. Six isolates with the widest zones of inhibition on the indicator lawn were selected for bacteriocin production. These isolates had exactly the same morphological, physiological and biochemical characteristics. The ribosomal RNA sequence was 99.5% identical with Enterococcus faecalis VRE 1492. The identification was confirmed through DNA homology test by the EMBL Genbank, Canada. This bacterium produced the L-isomer lactic acid. The amount of bacteriocin produced by the bacterium was optimized by growing the bacterium at different growth media, initial pH and fermentation time. Maximum production of bacteriocin was achieved in MRS (De Man Rugosa and Sharpe) medium (with glucose) at pH 7.50. The crude bacteriocin inhibited the growth of gram-positive bacteria such as Lactobacillus sake 15521 and Listeria innocua. The gram-negative bacteria such as Escherichia coli DH 5-alpha (with plasmid, PUC), Salmonella typhii and Staphylococcus aureus were weakly inhibited. Other microorganisms such as Lactobacillus curvatus D31685, Lactobacillus confusius M23036, Lactococcus lactis MG1363, Leuconostoc paramesenteroides S67831, Pediococcus pentosaceus M58834, Saccharomyces cerevisiae SS553 (wild type) and Escherichia coli JM109 (no plasmid) were not inhibited. [source] Detection of Sublethal Thermal Injury in Salmonella enterica Serotype Typhimurium and Listeria monocytogenes Using Fourier Transform Infrared (FT-IR) Spectroscopy (4000 to 600 cm,1)JOURNAL OF FOOD SCIENCE, Issue 2 2008H.M. Al-Qadiri ABSTRACT:, Fourier transform infrared (FT-IR) spectroscopy (4000 to 600 cm,1) was utilized to detect sublethally heat-injured microorganisms: Salmonella enterica serotype Typhimurium ATCC 14028, a Gram-negative bacterium, and Listeria monocytogenes ATCC 19113, a Gram-positive bacterium. A range of heat treatments (N= 2) at 60 °C were evaluated: 0D (control), 2D, 4D, 6D, and 8D using a D60 °C (S. enterica serotype Typhimurium ATCC 14028 = 0.30 min, L. monocytogenes ATCC 19113 = 0.43 min). The mechanism of cell injury appeared to be different for Gram-negative and Gram-positive microbes as observed from differences in the 2nd derivative transformations and loadings plot of bacterial spectra following heat treatment. The loadings for PC1 and PC2 confirmed that the amide I and amide II bands were the major contribution to spectral variation, with relatively small contributions from C-H deformations, the antisymmetric P==O stretching modes of the phosphodiester nucleic acid backbone, and the C-O-C stretching modes of polysaccharides. Using soft independent modeling of class analogy (SIMCA), the extent of injury could be predicted correctly at least 83% of the time. Partial least squares (PLS) calibration analysis was constructed using 5 latent variables for predicting the bacterial counts for survivors of the different heat treatments and yielded a high correlation coefficient (R= 0.97 [S. enterica serotype Typhimurium] and 0.98 [L. monocytogenes]) and a standard error of prediction (SEP= 0.51 [S. enterica serotype Typhimurium] and 0.39 log10 CFU/mL [L. monocytogenes]), indicating that the degree of heat injury could be predicted. [source] Numerical Analysis of Survival of Listeria monocytogenes during In-Package Pasteurization of Frankfurters by Hot Water ImmersionJOURNAL OF FOOD SCIENCE, Issue 5 2007Lihan Huang ABSTRACT:, The objective of this research was to develop and validate a more accurate method to analyze and calculate the inactivation of Listeria monocytogenes in frankfurter packages during postlethality hot water immersion heating and the subsequent cooling processes. Finite difference analysis with implicit scheme was used to simulate the heat transfer process during in-package pasteurization of frankfurters. A volumetrically distributed simulation method was developed to calculate the lethality of the thermal treatment. The simulation method was validated using frankfurter packages inoculated with a 4-strain cocktail of L. monocytogenes. Experimental results showed that the numerical analysis model could accurately simulate the heat transfer process during heating and cooling of frankfurter packages. The simulated temperatures on the surface or in the middle of the package matched very closely with the experimental observations. Using the simulated temperature distribution in the packages, the integrated lethality simulation method, based on the volumetric distribution of bacteria, could accurately predict the reduction in the bacterial counts. The calculation results were on average within 0.3 log(CFU/g) difference from the experimental observations, while the General Method systematically underestimated the bacterial reductions by approximately 0.9 log(CFU/g). The study shows that the integrated lethality method is more accurate than the General Method in calculating the lethality of thermal processes for conduction-heated foods. [source] Invasiveness and Intracellular Growth of Multidrug-Resistant Salmonella and Other Pathogens in Caco-2 CellsJOURNAL OF FOOD SCIENCE, Issue 2 2007S.-H. Kim ABSTRACT:, The increase of multidrug-resistant pathogens of human and animal origins is a major public health concern. For a better understanding of the health consequences of multidrug-resistant bacteria transmitted from animal products to humans, the host interaction of zoonotic Salmonella isolates along with other pathogenic and commensal bacteria was evaluated using a human intestinal Caco-2 cell system. Multidrug-resistant S. Agona, S. Heidelberg, and S. Typhimurium possessed plasmid-mediated class 1 integrons. The S. Typhimurium DT104 isolate from ground beef showed the well-known genotypic and phenotypic resistance characteristics of the species, and contained the chromosomally located class 1 integron. Among the multidrug-resistant Salmonella isolates, the S. Heidelberg 219 had the highest invasion number at 1.0 × 104 CFU/mL, followed by the S. Typhimurium DT104 isolate at 7.7 × 103 CFU/mL. Listeria monocytogenes was the best performer among the tested species in invading the Caco-2 cell. Multidrug-resistant opportunistic pathogens Klebsiella pneumoniae and Pseudomonas aeruginosa were also able to invade the cells. The invasion of S. Heidelberg 219, S. Typhimurium DT104, L. monocytogenes, K. pneumoniae, and P. aeruginosa into the Caco-2 cells was not affected even in the presence of commensal E. coli. During the intracellular growth of S. Heidelberg 219, S. Typhimurium DT104, and L. monocytogenes, the bacterial counts increased 2 log cycles in 9 h in the Caco-2 cells. Therefore, these strains could rapidly proliferate after their invasion into the cells. [source] 1-Methylcyclopropene Counteracts Ethylene-Induced Microbial Growth on Fresh-Cut WatermelonJOURNAL OF FOOD SCIENCE, Issue 6 2006Bin Zhou ABSTRACT:, The effects of exogenous ethylene, 1-methylcyclopropene (1-MCP), or both on microbial growth on watermelon fruit and watermelon slices were investigated. Freshly harvested seedless watermelons (Citrullus lanatus, cv. Sugar Heart) were treated with 0.5 or 1.0 ppm 1-MCP, 10 ppm ethylene, 1-MCP + ethylene, or left untreated as controls. Fruits were processed into wedge-shaped slices, packaged into rigid trays sealed with a polyethylene film with a 29.2 pmol s,1 m,2 Pa,1 oxygen transmission rate. The slices were evaluated after 0-, 6-, and 12-d storage at 5 °C. Ethylene treatment alone increased the populations of aerobic bacteria, lactic acid bacteria, and yeasts and molds on the packaged slices during storage compared to those on corresponding control slices and resulted in extensive juice leakage from the slices. The ethylene treatment also resulted in high aerobic bacterial counts throughout the flesh of whole melons compared to the controls. Treating watermelons with 0.5 or 1.0 ppm 1-MCP prior to ethylene exposure counteracted the deleterious effects of ethylene. Extending the time from harvest to 1-MCP treatment increased the population of aerobic bacteria, but had no detectable effect on the growth of lactic acid bacteria or yeasts and molds. The results indicate that low concentrations (0.5 or 1.0 ppm) of 1-MCP can be used on whole watermelon to avoid deleterious effects of exogenous ethylene to which the melons could be exposed during shipping or storage. [source] Quality Characterization of Farmed Atlantic Halibut During Ice StorageJOURNAL OF FOOD SCIENCE, Issue 2 2006Christelle Guillerm-Regost ABSTRACT: A quality index method (QIM) was developed for farmed Atlantic halibut and together with instrumental, chemical, sensory, and bacteriological analysis, quality changes of halibut stored on ice for 26 d was evaluated. Two groups of fish were fed diets that differed only in the source of lipid, where 1 diet contained only marine oil sources and the other a 50/50 mixture of marine and soybean oil. Fish were slaughtered after 1 y and then stored on ice for 26 d. The fish were sampled on day 1, day 2, and every 2nd day after that. Dietary lipid sources had no effect on freshness, (ATP) degradation (K-value), texture, color, or liquid-holding capacity. The QIM scores increased with storage time, in particular the appearance and eyes parameters. The QIM is a good freshness indicator for halibut. The K-value was strongly correlated with storage time (r= 0.99), while total bacterial counts increased after 7 to 8 d of ice storage. The texture, liquid-holding capacity, and color were significantly affected by storage time during the early period of storage, probably due to rigor stiffness and rigor resolution. The texture, liquid-holding capacity, and color did not change significantly from approximately day 8 of storage until the end of the experiment at day 26. [source] Hydrogen Peroxide and Calcium Chloride Added to Irrigation Water as a Strategy to Reduce Bacterial Populations and Improve Quality of Fresh MushroomsJOURNAL OF FOOD SCIENCE, Issue 6 2005Naveen Chikthimmah ABSTRACT The quality and value of fresh mushrooms are often diminished by the presence of high bacterial populations that cause a brown, blotchy appearance. The objective of the present research was to evaluate the addition of hydrogen peroxide and/or calcium chloride to irrigation water as a means to reduce total bacterial populations on fresh mushrooms. Crops were grown using commercial mushroom growing practices except for the addition of 0.75% hydrogen peroxide and/or 0.3% calcium chloride irrigation water added to the crop starting 11 d after the casing layer was applied on top of mushroom compost. Irrigation water without the added treatments acted as the control. Mushrooms were aseptically sampled from the production beds for enumerating bacterial counts. Total aerobic bacterial populations were determined by standard microbiological plating procedures. Mushroom whiteness (L -value) and color (delta E) after harvest and postharvest storage were measured using a Minolta chromameter. Harvested mushrooms were separated by treatment and weighed to record yield. Mushrooms irrigated with water (control) had 7.3 log colony-forming units (CFU) of aerobic bacterial populations per gram of fresh mushroom tissue. Compared with the control, irrigation with 0.75% hydrogen peroxide and 0.3% calcium chloride reduced the bacterial populations on fresh mushrooms by 87% (6.4 log CFU/g). Irrigation with hydrogen peroxide and calcium chloride significantly enhanced mushroom whiteness after harvest as well as after 6 d of postharvest storage at 12 °C. The irrigation treatments did not have a significant effect on crop yields; hence, the addition of hydrogen peroxide and calcium chloride to irrigation water was demonstrated to have good potential as a practical strategy to reduce bacterial populations and to improve the quality of fresh mushrooms. [source] Bacterial Culture and DNA Checkerboard for the Detection of Internal Contamination in Dental ImplantsJOURNAL OF PROSTHODONTICS, Issue 5 2009Rodrigo Edson Santos Barbosa DDS Abstract Purpose: The aim of this in vitro study was to evaluate the bacterial leakage along the implant,abutment interface by the conventional bacterial culture and DNA Checkerboard hybridization method. Materials and Methods: Twenty Branemark-compatible implants with a 3.75-mm diameter and external hexagonal platform were randomly placed in two groups of ten implant,abutment assemblies each. One group was used to analyze bacterial counts by DNA Checkerboard hybridization and the other by a conventional bacterial culture. Suspensions of Fusobacterium nucleatum (3 ,l) were injected into the grooved internal cylinders of each implant assembly, and the abutment was connected by a 32 Ncm torque. The combined implant,abutments were individually placed in tubes containing the CaSaB culture medium and incubated in a bacteriological constant temperature oven for 14 days. The samples were observed daily as to the presence of turbidity, and after the designated time the microorganisms were collected from the implant interiors and analyzed by the two methods. Results: After 14 days, six implant,abutment assemblies showed turbidity. Both methods indicated reduced microorganism counts in samples from the interior of the implant,abutment assemblies after incubation in the culture medium; however, the number of counts of F. nucleatum was higher by the DNA Checkerboard method when compared to the group analyzed by conventional bacterial cultures (p < 0.05). Conclusion: The DNA Checkerboard method was shown to be more sensitive than conventional cultures in the detection of microorganisms. [source] | |||||||||||||||||||