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Field Gel Electrophoresis (field + gel_electrophoresis)
Kinds of Field Gel Electrophoresis Selected AbstractsWater soluble fraction of solar-simulated light-exposed crude oil generates phosphorylation of histone H2AX in human skin cells under UVA exposureENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 6 2007Yuko Ibuki Abstract Crude oil contains compounds, which have toxic and cancer-causing properties to humans. The oil spilled in environments is usually exposed to sunlight; however, the toxicity of sunlight-exposed oil is poorly understood. In this study, we found that the water soluble fraction (WSF) of crude oil irradiated with solar-simulated light (SSL) generated phosphorylation of histone H2AX (,-H2AX) in human skin cells under UVA irradiation, which was due to the formation of DNA double strand breaks (DSBs). Crude oil was exposed to SSL for ,7 days. The WSF obtained from unexposed crude oil showed no toxicity, whereas the WSF obtained from crude oil pre-exposed to SSL induced acute cell death on exposure to UVA irradiation (induction of phototoxicity), which was more remarkable in human skin fibroblasts than human skin keratinocytes. ,-H2AX was detected in both cell lines immediately after treatment with the WSF plus UVA. Interestingly, ,-H2AX was detectable even at low SSL- and UVA-doses, which induced no cytotoxicity. The WSF of crude oil irradiated with SSL, generated DSBs under UVA irradiation, which were detected by biased sinusoidal field gel electrophoresis. This was confirmed using xrs-5 cells isolated from CHO-K1 cells, which are deficient in a repair enzyme for DSBs; the WSF plus UVA induced a more dramatic decrease in survival in xrs-5 cells than CHO-K1 cells. These findings demonstrate that exposure of crude oil to sunlight makes the WSF phototoxic, generating DSBs accompanying the appearance of ,-H2AX in human skin cells. Environ. Mol. Mutagen., 2007. © 2007 Wiley-Liss, Inc. [source] Features of Saccharomyces cerevisiae as a culture starter for the production of the distilled sugar cane beverage, cachaça in BrazilJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2010C.R. Campos Abstract Aims:, To evaluate the dominance and persistence of strains of Saccharomyces cerevisiae during the process of sugar cane fermentation for the production of cachaça and to analyse the microbial compounds produced in each fermentative process. Methods and Results:, Three S. cerevisiae strains were evaluated during seven consecutive 24-h fermentation batches using recycled inocula. The UFLA CA 116 strain had the largest population of viable organisms, and the maximum population was achieved in the fourth batch after 96 h of fermentation. The UFLA CA 1162 and UFLA CA 1183 strains grew more slowly, and the maximum population was reached in the seventh batch. Molecular characterization of isolated yeast cells using PFGE (pulse field gel electrophoresis) revealed that more than 86% of the isolates corresponded to the initially inoculated yeast strain. The concentration of aldehydes, esters, methanol, alcohol and volatile acids in the final-aged beverages were within the legal limits. Conclusions:, Cachaça produced by select yeast strains exhibits analytical differences. UFLA CA 1162 and UFLA CA 116 S. cerevisiae isolates can be considered the ideal strains for the artisanal production of cachaça in Brazil. Significance and Impact of the Study:, The use of select yeast strains can improve the quality and productivity of cachaça production. Our findings are important for the appropriate monitoring of yeast during sugar cane fermentation. In addition, we demonstrate that UFLA CA 116 and UFLA CA 1162, the ideal yeast strains for cachaça production, are maintained at a high population density. The persistence of these yeast strains in the fermentation of sugar cane juice promotes environmental conditions that prevent or decrease bacterial contamination. Thus, the use of select yeast strains for the production of cachaça is a viable economic alternative to standardize the production of this beverage. [source] Comparison of Campylobacter jejuni genotypes from dairy cattle and human sources from the Matamata-Piako District of New ZealandJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2008B.J. Gilpin Abstract Aims:, To identify the prevalence and types of Campylobacter jejuni carried by dairy cattle and the extent of overlap of these types with those causing disease in humans. Methods and Results:, Faecal samples from 410 dairy cattle were collected from 36 farms in the Matamata-Piako district in New Zealand. Campylobacter jejuni was isolated on all 36 farms, with a prevalence of 51% (95% CI 45,57) in dairy cattle and 65% (95% CI 58,72) in calves. Eighty-nine of these isolates were typed using Penner serotyping and pulsed field gel electrophoresis and were compared with 58 human C. jejuni isolates from people resident within this study area. Conclusions:,Campylobacter jejuni were found in the faeces of over half of the dairy cows and calves examined. Twenty-one per cent of the bovine isolates and 43% of the human isolates formed indistinguishable clusters of at least one bovine and one human isolate. Significance and Impact of the Study:, While a direct link between bovine isolates and human cases was not demonstrated, the finding of indistinguishable genotypes among C. jejuni isolates from bovine and human sources confirms that dairy cows and calves are a potential source of human campylobacteriosis. Barriers to separate bovine faecal material from the general public are therefore important public health measures. [source] Development of a molecular method for the typing of Brettanomyces bruxellensis (Dekkera bruxellensis) at the strain levelJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2007C. Miot-Sertier Abstract Aims:, In recent years, Brettanomyces/Dekkera bruxellensis has caused increasingly severe quality problems in the wine industry. A typing method at the strain level is needed for a better knowledge of the dispersion and the dynamics of these yeasts from grape to wine. Methods and Results:, Three molecular tools, namely random-amplified polymorphic DNA, PCR fingerprinting with microsatellite oligonucleotide primers and SAU-PCR, were explored for their relevance to typing strains of Brettanomyces bruxellensis. The results indicated that discrimination of each individual strain was not possible with a single PCR typing technique. We described a typing method for B. bruxellensis based on restriction enzyme analysis and pulse field gel electrophoresis (REA-PFGE). Results showed that electrophoretic profiles were reproducible and specific for each strain under study. Conclusions:, Consequently, REA-PFGE should be considered for the discrimination of B. bruxellensis strains. This technique allowed a fine discrimination of B. bruxellensis, as strains were identified by a particular profile. Significance and Impact of the Study:, This study constitutes a prerequisite for accurate and appropriate investigations on the diversity of strains throughout the winemaking and ageing process. Such studies will probably give clearer and more up-to-date information on the origin of the presence of Brettanomyces in wine after vinification when they are latent spoilage agents. [source] Detection and distribution of probiotic Escherichia coli Nissle 1917 clones in swine herds in GermanyJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2006S. Kleta Abstract Aims:, To verify the presence of Escherichia coli Nissle 1917 as a natural isolate in swine and to characterize in vitro probiotic properties as well as in vivo persistence in a feeding experiment. Methods and Results:, During studies on the intestinal microflora of pigs, we isolated E. coli Nissle 1917 sporadically from a pig population over a period of 1 year. The identity of the isolates as E. coli Nissle 1917 was verified by serotyping, Nissle-specific PCR, macrorestriction analysis (pulsed field gel electrophoresis) and the determination of in vitro probiotic properties in invasion and adhesion assays using a porcine intestinal epithelial cell line. Both the E. coli isolates and the E. coli Nissle 1917 strain showed strong reductions in adhesion of porcine enteropathogenic E. coli and invasion of Salmonella typhimurium with epithelial cells in vitro, with a probiotic effect. Screening of five epidemiologically unlinked swine farms and two wild boar groups showed one farm positive for E. coli Nissle 1917. A feeding experiment with four piglets showed viable E. coli Nissle 1917 in the intestine of three animals. Conclusions:, The results of this study suggest that the E. coli Nissle 1917 strain is already partially established in swine herds, but the colonization of individual animals is variable. Significance and Impact of the Study:, We report natural, long-term colonization and transmission of the probiotic E. coli Nissle 1917 strain in a swine herd, characterized individual persistence and colonization properties in swine and established an in vitro porcine intestinal epithelial cell model of probiotic action. The results of this study would have implications in the use of this strain as a probiotic in swine and contribute to a better understanding of the individual nature of intestinal bacterial persistence and establishment. [source] Molecular fingerprinting evidence of the contribution of wildlife vectors in the maintenance of Salmonella Enteritidis infection in layer farmsJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2003E. Liebana Abstract Aims: To provide molecular fingerprinting evidence of the contribution of wildlife vectors in the on-farm epidemiology of Salmonella Enteritidis infections. Methods and Results:Salmonella Enteritidis strains were isolated from wildlife and from farm environment samples collected in 10 egg layer farms. Isolates were typed using plasmid profiling, XbaI-pulsed field gel electrophoresis and PstI,SphI ribotyping. In all 10 farms we were able to identify the same S. Enteritidis clones in wildlife vectors and farm environment. On several occasions the same clones were found before and after cleansing and disinfecting the farm premises. Also in some instances the same clones were present in mice samples, egg contents and spent hens. Conclusions: Definitive molecular evidence for the involvement of several wildlife species (mice, rats, flies, litter beetles and foxes) in the maintenance of S. Enteritidis infection on farms has been presented. Failures in biosecurity seriously compromise the control of this pathogen on laying farms. Significance and Impact of the Study: This paper reports on the use of molecular tools for the study of the epidemiology of S. Enteritidis. It gives useful information to be considered in control programmes for this organism on poultry farms. [source] Comparison of phenotypic and genotypic markers for characterization of an outbreak of Salmonella serotype Havana in captive raptorsJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2003M.P. Reche Abstract Aims: To establish a typing method for tracing the epidemic relationship of 16 strains of Salmonella serotype Havana isolated from captive raptors showing no symptomatology and residing in a wildlife hospital in Spain. Methods and Results: Antimicrobial susceptibility testing, ribotyping, pulsed field gel electrophoresis (PFGE) and amplified fragment length polymorphism (AFLP) methodology were applied. Ten unrelated strains of serotype Havana were included as a control group to provide a basis of for the efficiency of the different markers used. All outbreak-related strains were resistant to nalidixic acid and streptomycin and showed the same ripotype, pulsotype and AFLP pattern. Conclusions: This is the first time that AFLP analysis has been tested with serotype Havana isolates and it has demonstrated to be the most useful epidemiological tool for discriminating between unrelated and outbreak-related strains of this serotype. The results obtained suggest that all the Salmonella serotype Havana isolates represented a common outbreak strain whose origin of contamination could not be established although it is thought that it was the poultry meat used for raptors'diet. Significance and Impact of the Study: Our study suggests the importance of microbiological analysis of these products in order to prevent contamination and dissemination of Salmonellae in this kind of Hospital. [source] Investigation of the genetic diversity among isolates of Salmonella enterica serovar Dublin from animals and humans from England, Wales and IrelandJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2002E. Liebana Aims: To assess the degree of genetic diversity among animal Salmonella Dublin UK isolates, and to compare it with the genetic diversity found among human isolates from the same time period. Methods and Results: One hundred isolates (50 human and 50 animal) were typed using plasmid profiling, XbaI-pulsed field gel electrophoresis (PFGE) and PstI- SphI ribotyping. Antimicrobial resistance data to 16 antibiotics was presented, and the presence of class-I integrons was investigated by real-time PCR. Seven different plasmid profiles, 19 ribotypes and 21 PFGE types were detected. A combination of the three methods allowed clear differentiation of 43 clones or strains. Eighteen isolates were resistant to at least one antimicrobial; five of them were multi-resistant and of these, only three presented class I integrons. Conclusions: Ribotyping data suggest the existence of at least three very different clonal lines; the same distribution in well-defined groups was not evident from the PFGE data. The existence of a variety of clones in both animals and humans has been demonstrated. A few prevalent clones seem to be widely disseminated among different animal species and show a diverse geographical and temporal distribution. The same clones were found in animals and humans, which may infer that both farm and pet animals may act as potential vehicles of infection for humans. Some other clones seem to be less widely distributed. Clustering analysis of genomic fingerprints of Salmonella Dublin and Salm. Enteritidis isolates confirms the existence of a close phylogenetic relationship between both serotypes. Significance and Impact of the Study: This paper describes the utility of a multiple genetic typing approach for Salm. Dublin. It gives useful information on clonal diversity among human and animal isolates. [source] Susceptibility of selected freshwater fish species to a UK Lactococcus garvieae isolateJOURNAL OF FISH DISEASES, Issue 10 2009M Algöet Abstract Gram-positive cocci recovered from diseased rainbow trout from a farm in England were characterized by different methods, including pulsed field gel electrophoresis, as virulent Lactococcus garvieae serogroup 2 (pulsotype A1). Groups of rainbow trout were kept at a range of temperatures and injected intraperitoneally (i.p.) with one of the UK isolates, L. garvieae 00021. The 18 °C and 16 °C groups showed 67% and 28% mortality, respectively, by day 27 post-injection. Fish kept at 14 °C or lower were less susceptible (,3% mortality). Raising the temperature of all groups to 18 °C at day 27 post-injection did not result in recurrence of the disease, even though viable bacteria were recovered from all groups 42 days later. Grayling were highly susceptible, with 65% mortalities when challenged with 200 colony forming unit fish,1 by i.p. injection and 37% mortalities when exposed to effluent water from tanks containing affected rainbow trout. Other fish species tested, Atlantic salmon, brown trout and seven cyprinid species, were less susceptible. Viable L. garvieae was isolated from the internal organs of all species tested at the end of the trials, suggesting that they may pose a threat as possible carriers to susceptible farmed and wild fish. [source] Electrophoretic Karyotype of the Obligate Biotrophic Parasite Plasmodiophora brassicae Wor.JOURNAL OF PHYTOPATHOLOGY, Issue 6 2001H. Graf Classical genetic analysis is not possible with the protist Plasmodiophora brassicae due to the intracellular life of this obligate biotrophic parasite. An electrophoretic karyotype has been obtained using contour-clamped homogeneous electric field gel electrophoresis to facilitate gene mapping of P. brassicae. Using two different separation conditions 16 chromosomal bands of P. brassicae were distinguished ranging in approximate size from 2.2 Mb to 680 kb. According to this determination of chromosome number and size, the total genome size of P. brassicae was estimated to be 20.3 Mb. The chromosomal bands were further designated by their hybridization pattern with repetitive elements of P. brassicae. The repetitive element H4 (1800 bp) hybridized with 14 chromosomal bands, but the sequence of H4 showed no homology to known centromere or telomere structures and revealed no repetitive motifs. [source] Meningococcal Carriage in Umra Pilgrims Returning from Saudi ArabiaJOURNAL OF TRAVEL MEDICINE, Issue 3 2003Annelies Wilder-Smith Background Moslems from all over the world go to Mecca and Medina in Saudi Arabia for two types of pilgrimage: the major pilgrimage (hajj) and the minor (umra). An international outbreak of meningococcal disease with serogroup W-135 occurred in association with hajj pilgrimage in the years 2000 and 2001, and it has been shown that pharyngeal carriage of a single W-135 strain was high in returning hajj pilgrims. We investigated the meningococcal carriage in umra pilgrims to determine the extent of circulation of this strain, during the minor pilgrimage. Method Tonsillopharyngeal swabs were taken from umra returnees. Serogrouping and pulsed field gel electrophoresis were performed on all meningococcal isolates. Subjects were questioned about the occurrence of symptoms of upper respiratory tract infection and use of antibiotics during the pilgrimage. Results were compared with those previously reported in hajj pilgrims. Results We enrolled 160 pilgrims returning from the umra pilgrimage in 2001. The meningococcal carriage rate was 1.3%, which is significantly lower compared with the hajj pilgrimage (17%; p<0.001). None of the umra pilgrims carried serogroup W-135, whereas 90% of the isolates in returning hajj pilgrims were Neisseria meningitidis W-135. Conclusions Meningococcal carriage during the umra pilgrimage was significantly lower compared with the hajj pilgrimage in the year 2001. No carriage of N. meningitidis W-135 was documented in umra pilgrims, whereas this was the predominant serogroup in hajj pilgrims. Public health measures to reduce the potential introduction of N. meningitidis W-135 into the countries of origin of returning pilgrims need to be prioritized for the hajj pilgrimage. [source] The use of (GTG)5 oligonucleotide as an RAPD primer to type Campylobacter concisusLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2006M.I. Matsheka Abstract Aim:, DNA fingerprinting using (GTG)5 oligonucleotide as a primer in a random amplified polymorphic DNA (RAPD) assay was assessed by typing isolates of Campylobacter concisus strains, collected over a period of 8 years. Methods and Results:, RAPD analysis using the (GTG)5 oligonucleotide as a primer was used to type 100 isolates of C. concisus comprising mostly isolates from children with diarrhoea. Using this method, 86% of the isolates were found to be genotypically diverse. Of these heterogeneous isolates, 25 of the strains were also shown to be genetically distinct in a previous study using pulsed field gel electrophoresis. The remaining isolates (14) could be classified into five profile groups based on the DNA fingerprinting patterns. The assay successfully identified epidemiologically linked strains from the unrelated genetically diverse pool of strains. Conclusions:, Laboratory RADP typing using the (GTG)5 primer proved to be useful in distinguishing related strains of C. concisus from a large pool of unrelated strains of this organism. Significance and Impact of the Study:, RAPD typing using (GTG)5 is a simple method that could be used to investigate the epidemiology of C. concisus. The results suggest that homologous lineages of C. concisus may exist within an otherwise heterogeneous species complex. However, these data need to be confirmed using a more robust typing method. [source] DNA-based subtyping of verocytotoxin-producing Escherichia coli (VTEC) O128ab:H2 strains from human and raw meat sourcesLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2003G. Domingue Abstract Aims:, To investigate subtyping methods for verocytotoxin-producing Escherichia coli (VTEC) O128ab:H2. Methods and Results:, Eleven human and food strains isolated over a 15-year period were examined. All were intimin (eae)-negative, but all possessed enterohaemolysin and VT1-encoding sequences which in nine strains were vtx1c variant. Ten strains had VT2 genes which were all vtx2d. Plasmid profiles and randomly amplified polymorphic DNA-PCR were not discriminatory. Long-PCR restriction fragment length polymorphism of amplicons bound by the p gene and the VT2A subunit had screening potential. Pulsed field gel electrophoresis (PFGE) using XbaI gave fine discrimination although VT2 sequences were located on a 220 kbp fragment conserved in nine strains and on a 200 kbp fragment in the 10th. Conclusions:, As a result of apparent clonality, PFGE proved essential for differentiation. Long-PCR has promise for screening but requires further evaluation of inter-strain variable sequences. Significance and Impact of the Study:, A combined phenotypic and genotypic screen, and PFGE for selected strains was effective. [source] Isolation of Shiga toxin-producing Escherichia coli O103 from sheep using automated immunomagnetic separation (AIMS) and AIMS-ELISA: sheep as the source of a clinical E. coli O103 case?LETTERS IN APPLIED MICROBIOLOGY, Issue 3 2002A.M. Urdahl Aims: To investigate whether a sheep flock was the original reservoir of a Shiga toxin-producing Escherichia coli (STEC) O103 strain causing a clinical human case and to compare the two diagnostic methods automated immunomagnetic separation (AIMS) and AIMS-ELISA. Methods and Results: AIMS detected Escherichia coli O103 in 36·5% of the samples and AIMS-ELISA detected E. coli O103 in 52·1% of the samples. Polymerase chain reaction detected stx1 and eae in three of 109 E. coli O103 isolates. Pulsed field gel electrophoresis showed that the sheep and human STEC O103 were characterized by distinctly different profiles. Conclusions: The sheep flock was shown to carry STEC O103, although an association between the sheep flock and the clinical human case could neither be proven nor eliminated. Substantial agreement was found between AIMS and AIMS-ELISA, but AIMS-ELISA was less time consuming and resulted in a higher recovery of E. coli O103. Significance and Impact of the Study: The study shows that sheep may be carriers of STEC that are associated with human disease and that the methods described can be used to increase the sensitivity of STEC detection. [source] The identification of circular extrachromosomal DNA in the nuclear genome of Trypanosoma bruceiMOLECULAR MICROBIOLOGY, Issue 2 2003N. S. Alsford Summary Nuclear extrachromosomal DNA elements have been identified in several kinetoplastids such as Leishmania and Trypanosoma cruzi, but never in Trypanosoma brucei. They can occur naturally or arise spontaneously as the result of sublethal drug exposure of parasites. In most cases, they are represented as circular elements and are mitotically unstable. In this study we describe the presence of circular DNA in the nucleus of Trypanosoma brucei. This novel type of DNA was termed NR-element (NlaIII repeat element). In contrast to drug-induced episomes in other kinetoplastids, the T. brucei extrachromosomal NR-element is not generated by drug selection. Furthermore, the element is stable during mitosis over many generations. Restriction analysis of tagged NR-element DNA, unusual migration patterns during pulsed field gel electrophoresis (PFGE) and CsCl/ethidium bromide equilibrium centrifugation demonstrates that the NR-element represents circular DNA. Whereas it has been found in all field isolates of the parasites we analysed, it is not detectable in some laboratory strains notably the genome reference strain 927. The DNA sequence of this element is related to a 29 bp repeat present in the subtelomeric region of VSG-bearing chromosomes of T. brucei. It has been suggested that this subtelomeric region is part of a transition zone on chromosomes separating the relatively stable telomeric repeats from the recombinationaly active region downstream of VSG genes. Therefore, we discuss a functional connection between the occurrence of this circular DNA and subtelomeric recombination events in T. brucei. [source] Karyotyping of Candida albicans and Candida glabrata from patients with Candida sepsisMYCOSES, Issue 5-6 2000Klempp-Selb The aim of this study was to determine the relatedness of Candida strains from patients suffering from Candida septicaemia by typing of Candida isolates from blood cultures and different body sites by pulsed field gel electrophoresis (PFGE using a contour-clamped homogenous electric field, CHEF). We studied 17 isolates of Candida albicans and 10 isolates of Candida glabrata from six patients. Four patients suffered from a C. albicans septicaemia, one patient from a C. glabrata septicaemia, and one patient had a mixed septicaemia with C. albicans and C. glabrata. Eight isolates from blood cultures were compared with 19 isolates of other sites (stool six, urine four, genital swab four, tip of central venous catheter three, tracheal secretion one, sputum one). PFGE typing resulted in 10 different patterns, four with C. albicans and six with C. glabrata. Five of the six patients had strains of identical PFGE patterns in the blood and at other sites. Seven isolates of a 58-year-old female with a C. glabrata septicaemia fell into five different PFGE patterns. However, they showed minor differences only, which may be due to chromosomal rearrangements within a single strain. Thus it appears, that the colonizing Candida strains were identical to the circulating strains in the bloodstream in at least five of six patients. [source] Sjögren's syndrome sufferers have increased oral yeast levels despite regular dental careORAL DISEASES, Issue 2 2008KCM Leung Aim:, To investigate the prevalence and quantity of oral yeasts and their association with oral candidiasis in Sjögren's syndrome (SS) patients receiving regular dental care. Materials and methods:, Yeasts in oral rinse and full-mouth supra-gingival plaque samples from 25 primary SS, 27 secondary SS and 29 control subjects were selectively cultured. All yeasts except single-species isolates were genotyped using pulsed field gel electrophoresis (PFGE). Results:, Ten (19%) SS sufferers had symptomless candidiasis. SS subjects had a higher prevalence (73%vs 7%) and quantity of yeasts than controls in both oral rinse and plaque samples (P < 0.05). The prevalence of yeasts in plaque was associated with candidiasis regardless of denture wearing (P , 0.04). Candida albicans was the predominant yeast isolated. PFGE showed 20 (66% of total) C. albicans isolate pairs, i.e. C. albicans species isolated from plaque and oral rinse samples of the same individual, were of closely related genetic clonal types (P < 0.01). Conclusions:, Despite effective oral hygiene, more SS subjects than controls had detectable levels of oral yeasts and their presence in supra-gingival plaque was associated with candidiasis. Candida albicans colonized supra-gingival biofilm even in well-maintained SS individuals, posing a challenge to the control of oral candidiasis. [source] Molecular characterization of CTX-M-15-producing clinical isolates of Escherichia coli reveals the spread of multidrug-resistant ST131 (O25:H4) and ST964 (O102:H6) strains in NorwayAPMIS, Issue 7 2009UMAER NASEER Nationwide, CTX-M-producing clinical Escherichia coli isolates from the Norwegian ESBL study in 2003 (n=45) were characterized on strain and plasmid levels. BlaCTX-M allele typing, characterization of the genetic environment, phylogenetic groups, pulsed field gel electrophoresis (PFGE), serotyping and multilocus sequence typing were performed. Plasmid analysis included S1 -nuclease-PFGE, polymerase chain reaction-based replicon typing, plasmid transfer and multidrug resistance profiling. BlaCTX-M-15 (n=23; 51%) and blaCTX-M-14 (n=11; 24%) were the major alleles of which 18 (78%) and 6 (55%), respectively, were linked to ISEcp1. Thirty-two isolates were of phylogenetic groups B2 and D. Isolates were of 29 different XbaI-PFGE-types including six regional clusters. Twenty-three different O:H serotypes were found, dominated by O25:H4 (n=9, 20%) and O102:H6 (n=9, 20%). Nineteen different STs were identified, where ST131 (n=9, 20%) and ST964 (n=7, 16%) were dominant. BlaCTX-M was found on ,100 kb plasmids (39/45) of 10 different replicons dominated by IncFII (n=39, 87%), FIB (n=20, 44%) and FIA (n=19, 42%). Thirty-nine isolates (87%) displayed co-resistance to other classes of antibiotics. A transferable CTX-M phenotype was observed in 9/14 isolates. This study reveals that the majority of CTX-M-15-expressing strains in Norway are part of the global spread of multidrug-resistant ST131 and ST-complex 405, associated with ISEcp1 on transferrable IncFII plasmids. [source] High prevalence of blaCTX-M extended-spectrum ,-lactamase genes in Escherichia coli isolates from pets and emergence of CTX-M-64 in ChinaCLINICAL MICROBIOLOGY AND INFECTION, Issue 9 2010Y. Sun Clin Microbiol Infect 2010; 16: 1475,1481 Abstract As a cause of community-acquired infections, extended-spectrum ,-lactamase (ESBL)-producing Escherichia coli constitute an emerging public-health concern. Few data on the molecular epidemiology of ESBL-producing E. coli isolates from pets are available in China. Detection and characterization of ESBL genes (blaCTX-M, blaSHV and blaTEM) was conducted among 240 E. coli isolates recovered from healthy and sick pets in South China from 2007 to 2008. The clonal relatedness of ESBL-producing E. coli isolates was assessed by pulsed field gel electrophoresis. ESBL-encoding genes were identified in 97 (40.4%) of the 240 isolates and 96 (40.0%) of them harbored CTX-M. The most common CTX-M types were CTX-M-14 (n = 45) and CTX-M-55 (n = 24). The recently reported CTX-M-64 was identified in three isolates. Isolates producing CTX-M-27, -15, -65, -24, -3 and -9 were also identified. Ten isolates carried two or three CTX-M types, with the combination of CTX-M-14 and CTX-M-55 being the most frequent (n = 6). ISEcp1 was identified in the upstream region of 93 out of the 107 blaCTX-M genes (86.9%). The sequence of the spacer region (45 bp) between ISEcp1 and the start codon of all blaCTX-M-55 genes (except four) was identical to that of blaCTX-M-64. No major clonal relatedness was observed among these CTX-M producers. It is suggested that the horizontal transfer of blaCTX-M genes, mediated by mobile elements, contributes to their dissemination among E. coli isolates from pets. Our finding of high prevalence of ESBL in E. coli of companion animal origin illustrates the importance of molecular surveillance in tracking CTX-M-producing E. coli strains in pets. [source] Comparative genomic analysis of European and Middle Eastern community-associated methicillin-resistant Staphylococcus aureus (CC80:ST80-IV) isolates by high-density microarrayCLINICAL MICROBIOLOGY AND INFECTION, Issue 8 2009R. V. Goering Abstract Infections as a result of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) are an issue of increasing global healthcare concern. In Europe, this principally involves strains of multi-locus sequence type clonal complex 80 sequence type 80 with methicillin resistance in a staphylococcal chromosomal cassette (SCCmec) type IV arrangement (CC80:ST80-IV). As with other CA-MRSA strains, CC80:ST80-IV isolates tend to appear uniform when analysed by common molecular typing methods (e.g. pulsed field gel electrophoresis, multi-locus sequence type, SCCmec). To explore whether DNA sequence-based differences exist, we compared the genetic composition of six CC80:ST80-IV isolates of diverse chronological and geographic origin (i.e. Denmark and the Middle East) using an Affymetrix high-density microarray that was previously used to analyse CA-MRSA USA300 isolates. The results revealed a high degree of homology despite the diversity in isolation date and origin, with isolate differences primarily in conserved hypothetical open reading frames and intergenic sequences, but also including regions of known function. This included the confirmed loss of SCCmec recombinase genes in two Danish isolates representing potentially new SCCmec types. Microarray analysis grouped the six isolates into three relatedness pairs, also identified by pulsed field gel electrophoresis, which were consistent with both the clinical and molecular data. [source] | |||||||||||||