title: Molecular Characterization of Uropathogenic Escherichia coli: Nalidixic Acid and Ciprofloxacin Resistance, Virulent Factors and Phylogenetic Background.
abstract: OBJECTIVE
  A proficient pathogen should be virulent, resistant to antibiotics, and epidemic. However, the interplay between resistance and virulence is poorly understood. Perhaps, the most commonly accepted view is that resistance to quinolones is linked to a loss of virulence factors. However, the low virulent phylogenetic groups may be more prone to acquire resistance to quinolones. The aim of this study was to identify and characterise the Nalidixic Acid (NA) and ciprofloxacin (CIP) resistant uropathogenic Escherichia coli (UPEC) isolates with respect to virulence and phylogenetic background, from hospital settings in Kolkata, an eastern region in India. Research based on these bacterial populations will help in understanding the molecular mechanisms underlying the association between resistance and virulence, that in turn, may help in managing the future disseminations of UTIs in their entirety.
  
  
  METHODS
  One hundred and ten E. coli isolates were screened against NA and CIP using Kirby-Bauer disk diffusion technique, following CLSI guidelines. Prevalence of virulent factor genes and distribution of phylogenetic groups amongst the isolates was determined by PCR, using gene specific primers against the different virulent factors and DNA markers (chuA, yjaA and DNA fragment, TSPE4.C2) respectively. Statistical analysis of the data was performed using SPSS software.
  
  
  RESULTS
  Resistance to both NA and CIP was reported in 75.5 % of the isolates which were analysed. The virulent determinants, papC, pap GII, papEF, afa, cnf1, hlyA and iroN were significantly predominant in the drug susceptible than the resistant isolates. A significant reduction of phylogroup B2 in NA (85.7% versus 64.6%, χ(2)P<0.001) and CIP (85.2 % versus 61.4%, χ(2)P<0.001) resistant UPEC isolates, followed by increase in predominance of non-B2 phylotypes (group D and group B1), were observed.
  
  
  CONCLUSIONS
  This is the first report from India that has indicated possible evidence on horizontal gene transfer from pathogenic to commensal strains and selection of the latter, on extensive usage of this group of antimicrobials in hospital settings, where these drugs were routinely prescribed for treating urinary tract infection. Therefore, this information necessitates surveillance programs and administration of effective strategies, to put an end to random prescription policies involving this group of antimicrobials.
authors.affiliation: Junior Research Fellow, Department of Biochemistry and Medical Biotechnology, School of Tropical Medicine , Kolkata, West Bengal, India .
authors.forename: Shreya
authors.initials: S
authors.lastname: Basu
authors.affiliation: Junior Research Fellow, Department of Biochemistry and Medical Biotechnology, School of Tropical Medicine , Kolkata, West Bengal, India .
authors.forename: Sandip Kumar
authors.initials: SK
authors.lastname: Mukherjee
authors.affiliation: Associate Professor, Department of Pharmacology, IPGMER , Kolkata, West Bengal, India .
authors.forename: Avijit
authors.initials: A
authors.lastname: Hazra
authors.affiliation: Associate Professor, Department of Biochemistry and Medical Biotechnology, School of Tropical Medicine , Kolkata, West Bengal, India .
authors.forename: Mandira
authors.initials: M
authors.lastname: Mukherjee
keywords: Ciprofloxacin; Drug resistance; Phylogeny; Virulence