Molecular characterization of Escherichia coli from dishwasher rubber seals

In this study 35 Escherichia coli isolates obtained from sampled dishwashers rubber seals were analysed with polymerase chain reactions (PCR) using specific primers for phylogenetic group, multilocus sequence type (MLST) determination the presence of 43 virulence-associated genes (VAGs) linked with intestinal and extraintestinal E. coli infections and the presence of some typical E. coli virulence plasmids’ sequences in order to assess their virulence potential and/or specific genes, associated with the adaption to a specific environment. It was found that all of the 35 E. coli isolates belonged to the commensal non-pathogenic phylogenetic group A and that the diversity of these E. coli isolates, according to MLST analysis, was relatively low. Further, the prevalence of virulence-associated genes among the dishwasher rubber seal E. coli isolates was also low. Only the following VAGs were detected: fimH, crl, fluA, picU, irp, fyuA, sitA, aslA. Of the five plasmid replication regions tested only RepFIA and RepFIIA were detected. The two sequences associated with conjugative plasmids namely traJ and traT, were detected in only one isolate. Based on the obtained results the studied isolates can be designated as commensal E. coli with low pathogenic potential. Due to the low diversity of sequence types, even among isolates obtained from dishwashers from different locations, there is a possibility that strains from certain clonal groups are more adapted to specific habitats outside warm-blooded hosts than strains of other sequence types.