Asymptomatic bacteriuria in pregnancy: epidemiological, clinical and microbiological approach

Asymptomatic urinary tract infection is a risk factor for fetal and maternal morbidity including development of pyelonephritis, premature labor and impaired intra-uterine development. In this study, 326 pregnant and 100 non-pregnant control women were screened for significant asymptomatic bacteriuria from April 8 to July 25, 1997 to gain insight into the prevalence rate, clinical characteristics of the disease and microbiological assessments of the causative agents. All the subjects were clinically identified to have no signs and symptoms of urinary tract infection (UTI). The age ranges of the study and control groups were between 15-40 years for both groups with mean of 25.1 and 25.3 years, respectively. Bacteriological screening of mid-stream urine (MSU) revealed that 24/326 (7%) and 3/100 (3%) were positive for asymptomatic bacteriuria in the study group and controls, respectively (P < 0.05). Further biochemical species identification showed that Escherichia coli was found in 11/24 (46%) followed by coagulase-negative staphylococci (CNS) in 8/24 (33%) and Citrobacter freundii in 2/24 (8%). Others found in smaller number included Staphylococcus aureus, Enterobacter cloacae and Proteus rettgeri in 1/24 (4%) each. Antimicrobial susceptibility test revealed that 10/11 (91%) of the E. coli isolates were resistant to ampicillin and amoxicillin and 10/11 (91%) of them sensitive to nitrofurantoin.