Clonal diversity of Chilean isolates of enterohemorrhagic Escherichia coli from patients with hemolytic-uremic syndrome, asymptomatic subjects, animal reservoirs, and food products
| Autor: | Valeria Prado, Consuelo Borie, Alberto Fica, Maritza Ríos, Marcela Alexandre, Michele Trucksis, C. Arellano, Myron M. Levine |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Microbiology (medical)
Serotype Disease reservoir Virulence Biology medicine.disease_cause Escherichia coli O157 Microbiology fluids and secretions Reference Values Genotype Pulsed-field gel electrophoresis medicine Animals Humans Typing Chile Serotyping Escherichia coli Phylogeny Disease Reservoirs Molecular epidemiology Genetic Variation Bacteriology biochemical phenomena metabolism and nutrition bacterial infections and mycoses Genes Bacterial Hemolytic-Uremic Syndrome Food Microbiology bacteria |
| Zdroj: | Journal of clinical microbiology. 37(3) |
| ISSN: | 0095-1137 |
| Popis: | To determine clonal relationship among Chilean enterohemorrhagic Escherichia coli (EHEC) strains from different sources (clinical infections, animal reservoirs, and food), 54 EHEC isolates (44 of E. coli O157, 5 of E. coli O111, and 5 of E. coli O26) were characterized for virulence genes by colony blot hybridization and by pulsed-field gel electrophoresis (PFGE). By colony blotting, 12 different genotypes were identified among the 44 E. coli O157 isolates analyzed, of which the genetic profile stx 1 + stx 2 + hly + eae + was the most prevalent. All human O157 strains that were associated with sporadic cases of hemolytic-uremic syndrome (HUS) carried both the stx 1 and stx 2 toxin-encoding genes and were eaeA positive. Only 9 of 13 isolates from human controls were stx 1 + stx 2 + , and 8 carried the eaeA gene. Comparison of profiles obtained by PFGE of Xba I-digested genomic DNA showed a great diversity among the E. coli O157 isolates, with 37 different profiles among 39 isolates analyzed. Cluster analysis of PFGE profiles showed a wide distribution of clinical isolates obtained from HUS cases and asymptomatic individuals and a clonal relationship among O157 isolates obtained from HUS cases and pigs. Analysis of virulence genes showed that a correlation exists among strains with the genotype stx 1 + stx 2 + eae + and pathogenic potential. A larger difference in the PFGE restriction patterns was observed among the EHEC strains of serogroups O26 and O111. These results indicate that several different EHEC clones circulate in Chile and suggest that pigs are an important animal reservoir for human infections by EHEC. Guidelines have been proposed for better practices in the slaughter of animals in Chile. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|