Analysis of Microbial Colonization, Including Multidrug-Resistant Gram-Negative Bacteria, in High-Risk Pregnant Women

Introduction: Preterm birth (PTB) remains a global challenge in obstetrics and is a leading cause of neonatal morbidity. It is estimated that at least 40% of all PTB are due to intrauterine infections. Given the concerning trend of multidrug resistance and limited resources, especially in gram-negative bacteria, early detection of colonization and risk factors is essential to prevent adverse outcomes. In this study, we analyzed the associations between maternal microbial colonization in pregnancy, particularly considering the prevalence of multidrug-resistant gram-negative (MRGN) and its impact on prenatal pregnancy-related complications. Methods: This retrospective, single-center cohort study consisted of 596 high-risk pregnant women, who were admitted to the hospital between February 2016 and April 2018. Based on their pregnancy complications, which led to admission, three subgroups were considered: non-infection-related (Non-Infected), infection-related (Infected), and Cervical-Insufficient. A total of 1319 swab samples collected from skin, perianal area, and vagina were screened on culture media and were categorized as nonpathogenic, MRGN, pathogenic gram-negative, pathogenic gram-positive bacteria, and unicellular organisms, for example, yeast. Statistical analyses included chi-square test. p -Values <0.05 were considered significant. Results: The main findings of this study indicate a low prevalence of MRGN with 2% in each subgroup and an increased occurrence of pathogenic gram-negative bacteria in the perianal area ( p < 0.05). However, no statistically significant association was found between microbial colonization and prenatal pregnancy-related complications. A combined screening of vaginal and perianal enhances the detection of pathogenic microorganisms, but no significant differences in pregnancy-related complications at admission were found. Additional perianal screening does not provide more evidence regarding the women’s health status. Conclusion: Therefore, general screening, including perianal swabs, cannot generally be recommended. Further research is needed to identify additional risk factors for the development of adverse pregnancy and neonatal complications.