Antimicrobial resistance in urinary bacterial isolates from pregnant women in rural Tanzania: implications for public health

Abstract

Treatment of asymptomatic bacteriuria and urinary tract infections in pregnancy can prevent adverse outcome for mother and child. However, antimicrobial resistance can impede effective chemotherapy. From April 1995 to March 1996, urine specimens from 5153 pregnant women in a rural area in northern Tanzania were inoculated on dip slides. Bacterial isolates from 101 positive dip slides were identified and tested for susceptibility to antimicrobial agents by disc diffusion. In total, 107 bacterial isolates were recovered, 71 Gram-negative and 36 Gram-positive. The most frequent isolates were Escherichia coli (n=27) and enterococci (n=15). E. coli isolates showed low rates of resistance to ampicillin (17%), mecillinam (9%), cefalexin (0%), nitrofurantoin (4%), trimethoprim-sulfamethoxazole (0%), trimethoprim (13%) and sulfamethoxazole (0%). Other Gram-negative bacteria displayed higher rates of resistance to these drugs. All enterococcal isolates were sensitive to ampicillin and only 2 were resistant to nitrofurantoin. Growth of E. coli from urine culture was correlated with adverse outcome of pregnancy (relative risk 4.13, 95% confidence interval 1.50-11.38). Antimicrobial susceptibility prevails in urinary isolates of E. coli and enterococci from rural areas of northern Tanzania. Susceptibility data from both rural and urban areas should be taken into account when planning antibiotic policies.