Prevalence study of antimicrobial resistant organisms in very preterm neonates.

Background: Preterm neonates have underdeveloped organs, a fragile skin barrier and an immature immune system rendering them susceptible to infection. These infants are at an increased risk of developing a healthcare-associated infection because of antibiotic exposure, invasive monitoring and the general risk of outbreaks within a hospital setting. The aim of this study was to investigate the prevalence of antimicrobial resistant organism carriage in very preterm neonates (i.e. born ≤ 32 weeks gestation) in the neonatal intensive care unit (NICU).

Methods: Neonates born ≤ 32 weeks' gestation in NMH from September 2022 to January 2023 were included. Swabs were taken at admission and fortnightly until week 10 of life. Screening investigations included ESBL (Extended Spectrum Beta-Lactamases) and AmpC producers, organisms resistant to gentamicin and ciprofloxacin, CPE (Carbapenemase-producing Enterobacterales), MRSA (Methicillin-resistant Staphylococcus aureus) and VRE (Vancomycin-resistant Enterococci). This differed from baseline screening by frequency of screening, and the recording of presence of AmpC-producers and ciprofloxacin-resistance. Ethical approval was sought and granted.

Results: Overall, 20 out of the 53 neonates (38%) included in the study were colonised with one or more resistant-gram-negative organism; 5 with ESBL (9%), 2 resistant to gentamicin (4%), 6 resistant to ciprofloxacin (11%) and 14 (26%) with AmpC producers. Three (6%) resistant gram-negative bacilli were detected on admission screens, and resistance rates peaked at week 4 where 14 screens were positive. No CPE, MRSA or VRE were isolated.

Conclusions: This study highlights the prevalence of antibiotic-resistant organisms in a vulnerable patient cohort, the very preterm infants. This review should prompt revision of the importance of infection prevention and control, antimicrobial stewardship and regular MDRO (multi-drug resistant organism) screening in the neonatal critical care setting.