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Particular Strain (particular + strain)
Selected AbstractsEffects of clinical isolates of Pseudomonas aeruginosa on Staphylococcus epidermidis biofilm formationFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2010Maria Pihl Abstract Pseudomonas aeruginosa is often found in chronic infections, including cystic fibrosis lung infections and those related to chronic wounds and venous ulcers. At the latter sites, P. aeruginosa can be isolated together with Staphylococcus epidermidis, and we have therefore explored the effect of clinical isolates and laboratory strains of P. aeruginosa strains on colonization by S. epidermidis in dual-species biofilms. Biofilm formation was assayed using 16S rRNA FISH and confocal laser scanning microscopy. Among the six P. aeruginosa strains tested, one particular strain, denoted 14:2, exerted a significant inhibitory effect, and even after 6 h, S. epidermidis levels in dual-species biofilms were reduced by >85% compared with those without P. aeruginosa. Interestingly, strain 14:2 was found to be negative for classical virulence determinants including pyocyanin, elastase and alkaline protease. Therefore, we suggest that less virulent phenotypes of P. aeruginosa, which may develop over time in chronic infections, could counteract colonization by S. epidermidis, ensuring persistence and dominance by P. aeruginosa in the host micro-habitat. Further studies are required to explain the inhibitory effect on S. epidermidis, although extracellular polysaccharides produced by P. aeruginosa might play a role in this phenomenon. [source] Strain persistence of invasive Candida albicans in chronic hyperplastic candidosis that underwent malignant changeGERODONTOLOGY, Issue 2 2001DW Williams Abstract Objectives: The aim of this study was to assess persistence and tissue invasion of Candida albicans strains isolated from a 65 year-old patient with chronic hyperplastic candidosis (CHC), that subsequently developed into squamous cell carcinoma (SCC). Materials and Methods: C. albicans (n=7) were recovered from the oral cavity of the patient over seven years. Confirmation of CHC and SCC in this patient was achieved by histopathological examination of incisional biopsy tissue. DNA fingerprinting was performed on the seven isolates from the CHC patient together with a further eight isolates from patients with normal oral mucosa (n=2), chronic atrophic candidosis (n=1), SCC (n=1) and CHC (n=4). Genotyping involved the use of inter-repeat PCR using the eukaryotic repeat primer 1251. Characterisation of the tissue invasive abilities of the isolates was achieved by infecting a commercially available reconstituted human oral epithelium (RHE; SkinEthic, Nice, France). After 24 h. C. albicans tissue invasion was assessed by histopathological examination. Results: DNA fingerprinting demonstrated strain persistence of C. albicans in the CHC patient over a seven year period despite provision of systemic antifungal therapy. The strain of C. albicans isolated from this patient was categorised as a high invader within the RHE compared to other isolates. Conclusions: Candidal strain persistence was evident in a patient with CHC over seven years. This persistence may be due to incomplete eradication from the oral cavity following antifungal therapy or subsequent recolonisation from other body sites or separate exogenous sources. The demonstration of enhanced in vitro tissue invasion by this particular strain may, in part, explain the progression to carcinoma. [source] GB virus C and TT virus infections in Japanese patients with autoimmune hepatitisJOURNAL OF MEDICAL VIROLOGY, Issue 2 2002Shuhei Nishiguchi Abstract The association of the newly identified viruses, GB virus C (GBV-C) and TT virus (TTV), with autoimmune hepatitis remains to be elucidated. Sera from 20 Japanese patients with autoimmune hepatitis and 50 volunteer blood donors were assayed for GBV-C RNA, antibodies to the GBV-C second envelope protein (E2), and TTV DNA. GBV-C RNA was examined by reverse-transcription polymerase chain reaction (PCR). Anti-GBV-C E2 (a marker of past infection) was tested by an enzyme-linked immunosorbent assay. TTV DNA was amplified by PCR using two different sets of primers: one derived from the original N22 sequence (Set A) and the other from the untranslated region (Set B). None of the patients or controls had GBV-C RNA. Anti-GBV-C E2 was found significantly more often in patients with autoimmune hepatitis (3/20) than in controls (1/50; P,=,0.034). The prevalence of TTV DNA detected by primers Set A and that detected with either Set A or B were similar among patients with autoimmune hepatitis (4/20 and 16/20, respectively) and controls (9/50 and 40/50, respectively). Clinical characteristics did not differ in association with any of these viral markers. Of the 13 TTV isolates amplified with Set A, seven were classified as genotype 1a, four as genotype 1b, and 2 as genotype 3; no particular strain was associated with autoimmune hepatitis. These findings provide no compelling evidence that GBV-C or TTV has a pathogenic role in autoimmune hepatitis. J. Med. Virol. 66:258,262, 2002. © 2002 Wiley-Liss, Inc. [source] Responses of Corcyra cephalonica (Stainton) to pirimiphos-methyl, spinosad, and combinations of pirimiphos-methyl and synergized pyrethrins,PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 2 2004Fangneng Huang Abstract Field control failures with pirimiphos-methyl against the rice moth, Corcyra cephalonica (Stainton), in Weslaco, Texas, USA, led us to investigate the susceptibility of this particular strain to pirimiphos-methyl, spinosad, pyrethrins synergized with piperonyl butoxide, and pirimiphos-methyl combined with synergized pyrethrins. In laboratory bioassays, 50 eggs of C cephalonica were exposed to untreated and insecticide-treated corn and sunflower seeds to determine larval survival after 21 days, egg-to-adult emergence after 49 days, and larval damage to seeds at both exposure periods. Pirimiphos-methyl at both 4 and 8 mg kg,1 did not prevent larval survival or egg-to-adult emergence of C cephalonica on either corn or sunflower seeds, and seed damage was evident at both rates. The C cephalonica strain was highly susceptible to spinosad at 0.5 and 1 mg kg,1. At both spinosad rates, reduction in larval survival, egg-to-adult emergence, and seed damage relative to the control treatment was ,93% on both corn and sunflower seeds. Pirimiphos-methyl and spinosad were generally more effective against C cephalonica on corn than sunflower seeds. The C cephalonica strain was completely controlled on corn treated with 1.5 mg kg,1 of pyrethrins synergized with 15 mg kg,1 of piperonyl butoxide. Many larvae survived and became adults on corn treated with synergized pyrethrins at ,0.75 mg kg,1. Corn treated with pirimiphos-methyl at 4, 6 or 8 mg kg,1 in combination with 0.38 to 1.5 mg kg,1 of synergized pyrethrins reduced larval survival by ,95%, egg-to-adult emergence by ,97%, and seed damage by ,94%. Our results suggest that the C cephalonica strain can be controlled on corn by combining pirimiphos-methyl with synergized pyrethrins or with synergized pyrethrins at the labeled rate. Although spinosad is not currently labeled for use on stored corn and sunflower seeds, it appears to be effective against C cephalonica on both commodities at very low rates. Copyright © 2004 Society of Chemical Industry [source] Combating resistance in a challenging, changing environmentCLINICAL MICROBIOLOGY AND INFECTION, Issue 2007F. W. Goldstein Abstract The prevalence of antimicrobial resistance for both Gram-positive and Gram-negative pathogens is escalating worldwide. Outbreaks of community- and hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) are being reported more frequently. Although antimicrobial resistance is well recognised as a global problem, decisions about appropriate intervention and treatment should be made at the level of the local hospital or healthcare system. Thus, local surveillance to identify prevalent pathogens, detect bacterial resistance and identify particular strains is necessary for selecting optimal treatment regimens. In addition, bactericidal antimicrobial agents with novel mechanisms of action and activity against multidrug-resistant bacteria, together with improved infection control measures, are needed to address this growing medical problem more effectively. [source] | ||||||||||