Antimicrobial susceptibility patterns of uropathogens isolated from pregnant women in KwaZulu-Natal Province: 2011 - 2016

Abstract

Background. Urinary tract infection (UTI) is one of the most common infections during pregnancy, which can lead to significant maternal and perinatal morbidity and mortality if left untreated. Challenges when treating UTIs in pregnancy include fetal protection and resistance development of uropathogens. Currently, the Essential Medicines List recommends nitrofurantoin to treat cystitis and ceftriaxone to treat pyelonephritis in pregnant women.

Objectives. To determine common pathogens causing UTI in pregnancy and their antibiotic susceptibility patterns.

Methods. A retrospective analysis was performed of laboratory data for positive urine specimens from obstetric departments of 6 KwaZulu- Natal Province hospitals during 2011 - 2016. Identification and susceptibility testing were performed using the VITEK 2 system. Results were interpreted according to the breakpoints of the Clinical and Laboratory Standards Institute, USA.

Results. From 5 971 positive urine specimens, the most common isolate was Escherichia coli (n=3 236; 54.2%), followed by Klebsiella pneumoniae (n=770; 12.9%). Group B streptococcus (GBS) (n=239; 4.0%) and Enterococcus faecalis (n=251; 4.2%) were the most common Gram-positive pathogens. E. coli displayed significant resistance to trimethoprim-sulfamethoxazole (65.1%), cephalothin (38.3%), cefuroxime (27.3%), ciprofloxacin (16.9%) and amoxicillin-clavulanic acid (17.1%). Resistance to ceftriaxone and nitrofurantoin remained low ‒ 9.1% and 7.7%, respectively. Among Gram-positive pathogens, GBS displayed 100% penicillin susceptibility and E. faecalis showed 92.9% susceptibility to ampicillin.

Conclusions. E. coli is unsurprisingly the most common cause of UTI in pregnancy in KwaZulu-Natal. Susceptibility to ceftriaxone and nitrofurantoin remains good. Among Gram positives, GBS is prevalent and susceptible to penicillin, while E. faecalis is susceptible to ampicillin. As antimicrobial resistance evolves, routine surveillance is necessary to modify recommended empirical antibiotic use.