Phylogenetic background, drug susceptibility and virulence factors of uropathogenic E. coli isolate in a tertiary university hospital in central Thailand.

Uropathogenic Escherichia coli (UPEC) is an important pathogen of the urinary tract infection (UTI) and is most commonly associated with human disease among the extraintestinal pathogenic E. coli (ExPEC). The aim of this study is to determine drug susceptibility pattern, virulence factors and the distribution of phylogenetic groups of UPEC in clinical isolates of a tertiary university hospital in central Thailand. A total of 119 UPEC isolates were tested for antimicrobial drug susceptibility. The prevalence of hemolysin, biofilm and the presence of papC and fimH genes were analyzed. The phylogenetic groups were determined by detection of yjaA and chuA genes and TspE4.C2 fragment. Antimicrobial susceptibility tests showed that the resistance of UPEC isolates to ampicillin, trimethoprim/ sulfamethoxazole, ciprofloxacin, and norfloxacin were 89.1, 60.5, 59.7 and 57.1%, respectively. Moreover, 38.7 and 62.2% of UPEC were ESBL producing and multidrug-resistant strains (MDR), respectively. The prevalence of hemolysin production, biofilm formation, and the presence of papC and fimH virulence genes were 5.9, 44.5, 29.4 and 82.4%, respectively. Phylogenetic classification revealed that 54.6% of UPEC belonged to group B2, followed by groups D (19.3%), A (15.1%) and B1 (10.9%). When compared to other groups, UPEC belongs to group B2 that harbored a battery of virulence factors and had a high rate of multidrug resistance (p<0.05). Stratified according to ciprofloxacin susceptibility, the prevalence of virulence of group B2 resistant strains was lower than the susceptible strains. MDR strains among groups B2 and D showed lower prevalence of virulence than non-MDR isolates. This study showed that multidrug resistance of UPEC and treatment of UTI with antimicrobial agents in this area should be highlighted. Since the relationship between virulence factor and drug susceptibility of UPEC is complex, further studies are required.