Putative Virulence Genes and Biofilm Production Among Typical Enteroaggregative Escherichia coli Isolates from Diarrhoeic Children in Kashmir and Andhra Pradesh

Fifty-eight typical EAEC isolates from children with diarrhoea were examined for HEp-2 cell adherence assay, presence of dispersin (aap), yersiniabactin (irp2), plasmid encoded toxins (pet), Shigella enterotoxin1 (set1A) and cryptic open reading frame (shf) putative virulence genes by polymerase chain reaction as well as for biofilm production. All the isolates showed aggregative adherence pattern on HEp-2 cells. All but five isolates (91.3 %) carried aap gene. While irp2, pet, set1A and shf genes were detected in 68.9, 5.1, 39.6, and 60.3 % isolates, respectively. Thirty-three (64.7 %) isolates out of 51 tested were found to produce biofilm which was found to be significantly associated only with set1A virulence gene (P = 0.025). Highest amount of biofilm was produced by a strain that possessed all the genes studied. Out of 14 isolates in which the most frequent gene combination (aap, irp2 and shf) was observed, only six produced biofilm. It is concluded that there is significant heterogeneity in putative virulence genes of EAEC isolates from diarrhoeic children and biofilm formation is associated with multiple genes.

Molecular epidemiology and in vitro antimicrobial susceptibility of Salmonella isolated from poultry in Kashmir

A total of 480 samples, comprising 429 faecal samples from healthy adult birds and 51 tissue samples from dead birds, were collected from four government poultry farms in the Kashmir valley from September 2007 to April 2008. In all, 33 Salmonella isolates were obtained. Of these, 28 (84.85%) isolates were Salmonella Gallinarum, 3 (9.09%) were Salmonella Enteritidis and the remaining 2 (6.06%) were Salmonella Typhimurium. All the isolates harboured the invA, sefA, stn and spvC virulence-specific genes. However, the sopB gene was found in only 90.9% of the isolates. Pulsed-field gel electrophoresis analysis of representative isolates revealed that the majority were related but a few belonged to different clones. The majority of the isolates were resistant to cefpodoxime, nalidixic acid and sulphadiazine and sensitive to chloramphenicol, cefotaxime and tetracycline. Isolation of multidrug-resistant Salmonella, including the zoonotically important serovars, revealed a potential threat not only to poultry but also to human health in Kashmir.