RESUMO
Non-O157 Shiga toxin-producing Escherichia coli (STEC) are recognized as an important group of bacterial enteropathogens. Here, we report the draft genome sequence of nine strains of non-O157 STEC isolated from ready-to-eat foods in Argentina. The whole-genome sequence data provide a better understanding of these isolates and will aid epidemiological investigation during outbreaks.
RESUMO
This study describes the prevalence of arrays of class 1 integron cassettes and Qnr determinants (A, B, and S) in 19 fluoroquinolone-resistant Escherichia coli isolates from chicken litter. qnrS and qnrA were the predominant genes in these fluoroquinolone-resistant isolates, and an uncommon array of aacA4-catB3-dfrA1 gene cassettes from a class1 integron was found. Additionally, aadA1 and dfrA1 gene cassettes, encoding resistance to streptomycin and trimethoprim, constituted the most common genes identified and was located on megaplasmids as well on the chromosome. Antibiotic resistance, pulsed-field gel electrophoresis (PFGE), and plasmid data suggest a genetically diverse origin of poultry E. coli isolates.
Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli/genética , Fezes/microbiologia , Integrons/genética , Animais , Impressões Digitais de DNA , Primers do DNA/genética , Eletroforese em Gel de Campo Pulsado , Proteínas de Escherichia coli/genética , Fluoroquinolonas , Plasmídeos/genética , Aves DomésticasRESUMO
During 2001-2005, 210 Salmonella enterica strains were isolated from seafood samples imported into US. Strains of S. enterica serovar Weltevreden were the most predominantly found among the 64 different serovars isolated. A total of 37 Salmonella Weltevreden isolates were characterized by pulsed-field gel electrophoresis (PFGE), plasmid profiles and antibiotic susceptibility to assess genetic diversity. Our results showed a low frequency of antibiotic resistance; 35 of the 37 isolates were sensitive to ampicillin, tetracycline, chloramphenicol, gentamicin, sulfisoxazole, streptomycin and kanamycin. Only two isolates, from samples originating in the Philippines and India, showed resistance to ampicillin and tetracycline and to streptomycin, sulfisoxazole and tetracycline, respectively. Of the 37 isolates, two isolates did not carry any plasmid and 35 isolates harbored several small and mega-plasmids. These isolates were differentiated into 10 distinct types based on plasmid profiles. Four different PFGE clusters were obtained with a genetic similarity of 66-76%. Four groups of isolates (formed by two or three isolates each) showed 100% similarity in the PFGE profiles. One of these groups included strains isolated in Vietnam in 2003, 2004 and 2005 from fish and shrimp. The other groups included strains isolated in Vietnam, Indonesia and Thailand in 2000, 2004 and 2005 from snail, shrimp and fish. Our findings show genetic diversity and temporal persistence of S. enterica serovar Weltevreden in recently monitored seafood imports.
Assuntos
Antibacterianos/farmacologia , Contaminação de Alimentos/análise , Salmonella enterica/isolamento & purificação , Alimentos Marinhos/microbiologia , Frutos do Mar/microbiologia , Animais , Análise por Conglomerados , Qualidade de Produtos para o Consumidor , Farmacorresistência Bacteriana/genética , Eletroforese em Gel de Campo Pulsado , Variação Genética , Humanos , Testes de Sensibilidade Microbiana , Plasmídeos , Salmonella enterica/classificação , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/genética , Caramujos/microbiologia , Especificidade da EspécieRESUMO
Between June 2000 and December 2001, 500 food samples were collected from supermarkets and shops selling ready-to-eat food in Rosario, Argentina, and examined for Escherichia coli. Forty-nine E. coli isolates from food samples were further characterized for virulence genes by multiplex polymerase chain reaction (PCR) targeting the stx1, stx2, stx2e, eaeA, CNF1, CNF2, Einv, LTI, STI, and STII genes in four groups. Out of 49 E. coli isolates screened by multiplex PCR, only 10 possessed Shiga toxin genes, stx1 and stx2 genes and none possessed the other genes. The Shiga toxin positive E. coli strains (STEC) were isolated from soft, cottage cheeses, chicken with sauce and vegetables mayonase. These E. coli isolates were serogrouped and belonged to O18 (two strains), O8, O57w, O79, O44, and O128; three strains were untypeable. Pulsed-field gel electrophoresis (PFGE) with XbaI generated a unique profile for each, having 10-15 bands ranging from 50 to 500 kb, except that strain ARG 20 generated small bands and was partly degraded. These strains are potential foodborne pathogens and their presence in ready-to-eat food illustrates the need to keep a careful watch for the source of pathogens and then develop methods to control them.
Assuntos
Escherichia coli/isolamento & purificação , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Genes Bacterianos , Argentina , Qualidade de Produtos para o Consumidor , Eletroforese em Gel de Campo Pulsado/métodos , Reação em Cadeia da Polimerase/métodosRESUMO
Guillain-Barre Syndrome (GBS) is a neuromuscular disorder and campylobacteriosis is known to trigger the onset of the disorder. A polymerase chain reaction (PCR) protocol was developed that could specifically amplify a 497-bp region of the UDP-galactose 4-epimerase (galE) gene sequence in campylobacters responsible for triggering the onset of GBS. The identity of the PCR product was confirmed by Hind III endonuclease restriction digestion, which produced the predicted 430 and 67-bp DNA fragments. The assay could detect the presence of the gene in Campylobacter suspensions containing as few as 5 cells ml(-1). The assay detected the presence of the gene in 17 of the 20 campylobacters isolated from chicken, 9 of the 13 campylobacters isolated from turkey and 7 of the 7 campylobacters isolated from human stools. All Campylobacter strains isolated from chicken, turkey and clinical samples were resistant to multiple antibiotics. The assay failed to detect the presence of the gene in five different microaerophilic strains of Helicobacter spp., E. coli and Salmonella spp. The entire diagnostic assay, including template preparation, amplification and electrophoresis, can be completed within 6 h.