Abstract:
Escherichia coli is a prevalent commensal bacterial species that also exists in certain
pathogenic forms which result in intestinal diseases. Two different pathotypes of E. coli that
exist in nature are Extra-intestinal Pathogenic E. coli (ExPEC) and Diarrheagenic E. coli
(DEC). Out of the ExPEC species the most common is Uropathogenic E. coli (UPEC). The
predominant etiology of Urinary tract infections (UTIs) is linked to UPEC. The existence
of complex pathotypes of E. coli can be related to the evolution of new hybrid pathotypes
of ExPEC and DEC which might be the result of horizontal gene transfer of transferable
genetic fragments. In the current study we have isolated and characterized 100 UPEC
isolates for their phylogeny, antibiotic resistance, virulence factors, virulence associated
genes (VAGs) and their pathogenic nature. In addition to this we have also detected DEC
genetic markers in the UPEC isolates. Most of the isolates were assigned to Phylogroup B2
(38%) and A (28%). The isolates had a high antibiotic resistance profile, where 96% of the
strains were resistant to multiple drugs thereby, considered as multiple drug resistant (MDR)
strains. Isolates were highly resistant to macrolides (100%) followed by Ampicillin (95%)
and Amoxicillin (80%). A large portion of isolates was resistant to different
fluoroquinolones. Among the tested isolates, 51% of the isolates also tested for Extended
Spectrum β-lactamases. The most common VAG detected in the isolates was fimH it was
present in 95% of the isolates. Out of the 100 isolates in our study 15 showed hybrid genetic
markers. The hybrid strains contained genetic markers from three DEC pathotypes i.e.
Enteropathogenic E. coli (EPEC), Enterohemorrhagic E. coli (EHEC), Enteroggregative E.
coli (EAEC). Among the 15 strains there were 5 UPEC/aEPEC/EHEC, 4 UPEC/EHEC, 3
UPEC/aEPEC, 2 UPEC/EAEC and 1 UPEC/tEPEC/EHEC isolates. The 15 hybrid isolates
were MDR in nature and the emergence of these MDR hybrid pathotypes poses a new
danger in the field of microbiology. There is need to monitor and study these pathotypes to
enable us to deal with them in an outbreak.
