مدى انتشار البيلة الجرثومية اللاعرضية، ومسبباتها البكتيرية، ونمط حساسيتها للمضادات الميكروبية لدى النساء الحوامل في مصراتة، ليبيا

Abstract

Background: Asymptomatic bacteriuria (ASB) is a common but often overlooked condition during pregnancy that can progress to symptomatic urinary tract infection, pyelonephritis, preterm labour, and low birth weight if left undetected and untreated. No local data on ASB were previously available for Misurata, Libya. Objective: To determine the prevalence of ASB among pregnant women in Misurata, identify the causative bacterial isolates, evaluate the diagnostic accuracy of dipstick chemical examination (nitrite and leukocyte esterase), and assess the antimicrobial susceptibility pattern of the isolated uropathogens. Methods: This descriptive cross-sectional study was conducted between November 2023 and August 2024 at the Lamis Clinic and Misurata Medical Centre. Clean-catch midstream urine samples were collected from 234 asymptomatic pregnant women and analyzed by chemical dipstick, microscopy, and quantitative culture. Bacterial isolates were identified by standard biochemical tests and API-20E, and antimicrobial susceptibility was determined by the Kirby-Bauer disc diffusion method, with E-test used to confirm vancomycin MIC in methicillin-resistant Staphylococcus aureus (MRSA) isolates. Results: ASB was detected in 27 of 234 women (11.53%). Gram-negative bacteria (59.25%) predominated over Gram-positive bacteria (40.74%). Klebsiella pneumoniae was the most frequent isolate (33.33%), followed by coagulase-negative staphylococci (29.62%), Escherichia coli (22.22%), Staphylococcus aureus (11.11%), and Pseudomonas aeruginosa (3.7%). No statistically significant associations were found between ASB and age, parity, trimester, or medical history (p > 0.05). The nitrite and leukocyte esterase dipstick tests showed low sensitivity (18.75% and 25.93%, respectively) but high specificity (99.54% and 90.87%), while pus cell count had the highest sensitivity (37.04%) among the screening tests. Gram-negative isolates were most susceptible to piperacillin-tazobactam and amikacin (81.2%), while Gram-positive isolates were most susceptible to cefuroxime and doxycycline (90.9%). Extended-spectrum beta-lactamase (ESBL) production was detected in 33.3% of Gram-negative isolates. Conclusion: ASB affects a notable proportion of pregnant women in Misurata. Dipstick screening alone is unreliable for detecting ASB, and quantitative urine culture remains the diagnostic gold standard. Routine screening and culture-guided antimicrobial therapy are recommended to reduce maternal and fetal complications.