Antimicrobial susceptibility of urinary bacterial isolates of pregnant women attending antenatal clinics of selected hospitals in Ilorin, Nigeria

Abstract

Background: Urinary tract infection (UTI) in pregnancy is associated with significant morbidity for both mother and baby. This study was aimed at determining the urinary bacterial isolates and their susceptibility to selected antibiotics among pregnant women attending antenatal clinics of selected Hospitals in Ilorin, Nigeria.

Methodology: A total of 300 pregnant women between the ages of 15 and 44 years were selected by random sampling technique from antenatal clinics of three randomly selected healthcare facilities in Ilorin, Nigeria; Civil Service Hospital, Sobi Specialist Hospital and Okelele Primary Health Center, between July and October 2021. Clean-catch mid-stream specimens of voided urine were collected from each participant, cultured on Cysteine- Lactose-Electrolyte Deficient (CLED) and Blood agar plates, and incubated aerobically at 37oC for 24 hours. The presence of significant bacteriuria (≥105 CFU/ml) was determined on the culture plate using the plate count method. Antibiotic susceptibility testing to selected antibiotics was done using Kirby-Bauer disk diffusion technique. Cefoxitin (30?g) was used as surrogate to determine phenotypic methicillin resistance in staphylococcus isolates, and the methicillin resistance (mecA) gene was detected by conventional PCR assay.

Results: Of the 300 pregnant participants, 49 (16.3%) were symptomatic for UTI while 251 (83.7%) were asymptomatic. Significant bacteria (monomicrobial) were isolated in 44 (14.7%) pregnant women; 28 (11.2%) of 251 asymptomatic and 16 (32.6%) of 49 symptomatic women, which showed that significant bacteriuria rate was higher with symptomatic than asymptomatic women (OR=3.861, 95% CI=1.889–7.893, p=0.0005), but significant bacteriuria rate did not differ with respect to age group of the women (x2=1.463, p=0.4811). The most common bacterial isolates were Escherichia coli (38.6%, 17/44) followed by coagulase negative staphylococci (CoNS) (22.5%, 9/44), Klebsiella pneumoniae (18.2%, 8/44), Staphylococcus aureus (15.9%, 7/44), Enterococcus sp (4.6%, 2/44) and Pseudomonas sp (2.3%, 1/44). Gram negative isolates showed high resistance rate of 73.1% to ampicillin and 65.4% to amoxicillin-clavulanic acid while Gram-positive isolates showed high resistant rate of 94.1% to penicillin. The Gram-positive isolates showed high susceptibility rate of 100% while the Gram-negative isolates showed moderate susceptibility of 69.2% to nitrofurantoin. Four of the 9 (44.4%) CoNS isolates were cefoxitin resistant and all the 4 (100%) carried mecA gene.

Conclusion: The isolation of bacterial pathogens resistant to the commonly prescribed antibiotics from pregnant women symptomatic and asymptomatic for UTI calls for early screening of all pregnant women for UTI during antenatal care service delivery.