Phenotypic Identification and Phylogenetic Characterization of Uropathogenic Escherichia coli in Symptomatic Pregnant Women With Urinary Tract Infections in South-Western Nigeria

The study reports the characterization of uropathogenic E. coli (UPEC) in urine samples of pregnant women with confirmed urinary tract infections (UTIs) in Ondo and Ekiti States, Nigeria.

Voided mid-stream urine samples were cultured on eosin methylene blue agar plates at 37oC and identified by conventional biochemical tests. Antibiotic susceptibility testing of isolates was by Kirby-Bauer’s disc diffusion technique. Phylogenetic typing of the isolates was by multiplex polymerase chain reaction (PCR).

The occurrence of UPEC in pregnant women in age group 25-35 years (66.0%) was high. Two hundred and sixty four uropathogenic E. coli comprising 133 (50.38%) in Ondo and 131 (49.62%) in Ekiti States were recovered from 400 samlpes analyzed. In all, prevalence of UTIs with positive cultures was 66.0%. Escherichia coli only was 56.5%, mixed-infection (9.5%), non-E. coli infection (12.5%) and no growth (21.5%). Resistance to antibiotics was high with diverse multiple antibiotic resistance patterns. Greater percentage of the screened representative UPEC isolates belonged to phylogenetic group D (65.0%), group A (28.0%), group B1 (6.7%) and none to group B2.

Escherichia coli belonging to phylogenetic group D appears to be a predominant uropathogen in this study area. Presence of chuA gene in most of the isolates shows the significance of iron acquisition in the pathogenesis and urovirulence of UPEC.