Etiology of asymptomatic bacteriuria, antimicrobial susceptibility patterns and associated risk factors among pregnant women attending antenatal clinic in western Kenya

Approximately 11.1% of pregnant women in Africa experience asymptomatic bacteriuria (ASB), and its proper understanding is critical due to its risks, including pyelonephritis in mothers and fetal mortality. However, a significant gap remains in understanding the optimal screening and treatment protocols for ASB in pregnant women. We assessed the etiology of asymptomatic bacteriuria, antimicrobial susceptibility patterns, and associated risk factors among pregnant women attending an antenatal clinic in western Kenya. Using a cross-sectional quantitative design, 285 asymptomatic pregnant women were recruited, interviewed using a questionnaire and provided urine for culture. Microbial susceptibility was tested using the Kirby Bauer disk diffusion technique and interpreted based on the Clinical and Laboratory Standards Institute guidelines. Asymptomatic bacteriuria prevalence was 16.3% (44/270), and increased with gestational age for trimester 1, 2 and 3 at 12%, 17.7% and 19.3%, respectively. Of the ASB cases, 45.5% (20/44) were caused by gram-negative bacteria, and 56.8% (25/44) by gram-positive bacteria. Isolated gram-negative bacteria were Escherichia coli (80%), Klebsiella pneumoniae (10%), Proteus mirabilis (5%) and Pseudomonas aeruginosa (5%), while the isolated gram-positive bacteria were coagulase-negative Staphylococcus species (52%), Enterococcus species (20%), Staphylococcus aureus (16%) and Streptococcus agalactiae (8%). Antibiotics with high sensitivity by gram-negative bacteria were azithromycin, meropenem, and tobramycin (100% susceptibility), while all isolates (100%) were resistant to trimethoprim-sulfamethoxazole. Gram-positive isolates were highly (100%) sensitive to gentamicin, ofloxacin, clindamycin and ampicillin, and 56% were resistant to trimethoprim-sulfamethoxazole. Women with at least a secondary school education had 2.47 times higher odds of getting asymptomatic bacteriuria (AOR = 2.47, 95% CI [1.09, 5.98], p = 0.036), while women between 25-34 years of age were at 2.23 times higher odds of ASB (AOR = 2.23, 95% CI [1.07, 4.63], p = 0.030). There is a need for extensive antimicrobial susceptibility testing to identify safe and effective antibiotics for treating ASB.