Evaluating the role of vertical transmission of antimicrobial resistance in neonatal sepsis
Ashley Styczynski, MD, MPH
BACKGROUND: Infection with antibiotic-resistant bacteria is an increasing cause of newborn deaths, particularly in developing countries such as Bangladesh. The true burden of antibiotic-resistant infections among newborns in Bangladesh is unknown, but limited data show 75-100% of the causative bacteria are resistant to first-line antibiotics. GAP: It is not known to what extent newborn infections with antibiotic-resistant bacteria may be caused by exposure to community-acquired bacteria that are transmitted from mother to baby and/or through healthcare contact. HYPOTHESIS: My hypothesis is that pregnant women in Bangladesh are colonized with antibiotic-resistant bacteria, independent of healthcare contact, and that this contributes to newborn infections from resistant bacteria. METHODS: We enrolled pregnant women presenting for delivery in Faridpur, Bangladesh, and assessed for colonization with antibiotic-resistant bacteria. We examined the association between colonization with prior exposures and compared bacteriologic findings to types of bacteria causing newborn infections. RESULTS: Of 177 pregnant mothers presenting for delivery, 16.9% were found to be colonized with extended-spectrum beta-lactamase (ESBL)-producing organisms on vaginal swabs, and 70.6% on rectal swabs. Colonization with carbapenem-resistant organisms (CRO) was less frequent with 4.0% of mothers colonized on vaginal swabs and 13.0% colonized on rectal swabs. The most common organisms isolated were ESBL E. coli followed by ESBL Klebsiella, which closely coincides with causative etiologies of neonatal sepsis. Hospitalization during pregnancy was the only factor consistently associated with ESBL and CRO colonization on univariable and multivariable analysis (RR 2.2-2.6, 95% CI 1.0-5.9). IMPACT: This study reveals that healthcare exposure is an important contributor to maternal colonization with antibiotic resistant bacteria. Additionally, vertical transmission may be a critical route of neonatal exposure to resistant organisms that ultimately lead to neonatal infections. Further investigations are needed into the role of healthcare facilities in propagating spread of antibiotic resistant bacteria and their role in newborn infections.