Introduction
Extended-spectrum β-lactamases (ESBLs) are a heterogeneous group of enzymes produced by certain bacteria that inactivate β-lactam antibiotics via hydrolysis. They are most often found inEnterobacteriaceae , especially Escherichia coli andKlebsiella pneumoniae . Because of antimicrobial resistance, diagnosing and treating ESBL-producing bacterial species are important challenges.1,2
The prevalence of ESBL-producing Enterobacteriaceae (ESBL-E) infection is not exactly known; however, the reported prevalence has increased globally in recent years,3-5 while the estimated prevalence in Asia is approximately 4.8% to 12.0%.2,6-8 Furthermore, the rates of ESBL-E infection in maternity wards and outpatient clinics are also increasing. Therefore, these issues related to ESBL-E infection are becoming more crucial among obstetricians.9
Following the report of maternal ESBL-E vaginal colonization as a precursor of mother-to-child transmission, the importance of vaginal colonization was recently noted.10 According to a recent systematic review, neonatal ESBL-E infection in neonatal intensive care units is associated with significant morbidity and mortality, with a mortality rate as high as 31%.11Meanwhile, the risk factors for ESBL-E infection in the general population include prior antibiotic treatment, increased illness severity, indwelling catheter use, and intensive care unit admission.12,13 However, the specific risk factors for ESBL-E vaginal colonization during pregnancy have not been studied, and the potential clinical implications are still unclear.14
With this background, we aimed to evaluate the changes in the rate of ESBL-E vaginal colonization in high-risk pregnancies over the study period and identify the risk factors for ESBL-E vaginal colonization during pregnancy. Further, we analyzed the perinatal outcomes of ESBL-E-positive patients.