Presence of New Delhi Metallo-Β-Lactamase (Ndm)–producing Enterobacter Cloacae in a Neonatal Icu: Importance of Surveillance Cultures for Early Detection

Enterobacter cloacae ( E. cloacae ) is a Gram-negative bacillus frequently isolated in Intensive Care Units (ICUs). Production of the New Delhi Metallo-β-lactamase (NDM) enzyme confers broad resistance to β-lactams, including carbapenems, limiting therapeutic options. In neonates, colonization by this multidrug-resistant microorganism (MDR) represents a high risk of infection and dissemination. Surveillance cultures (SCs) enable early identification of asymptomatic carriers, allowing immediate actions for MDR prevention and control in critical environments. Selection of E. cloacae NDM for this study was justified by its detection in 85% of SCs performed in a Neonatal ICU (NICU), highlighting its epidemiological relevance. The objective was to analyze the time elapsed between NICU admission and microbiological detection of E. cloacae NDM through SCs in a public hospital in São Paulo. A retrospective descriptive study conducted between July 2024 and May 2025. Laboratory data from SCs and electronic medical records were analyzed, considering time between NICU admission and laboratory detection (colonization), sampling sites, progression from colonization to healthcare-associated infections (HAIs), and mortality. Forty-seven E. cloacae NDM samples were identified in SCs from 28 neonates. Time between NICU admission and MDR identification was stratified by hospitalization week: 1st: 10.6%; 2nd: 40.5%; 3rd: 40.4%; 4th: 10.6%; 5th: 2.1%. Sampling sites were: anal 44.7%; oral 25.5%; axillary 17%; inguinal 8.5%; nasal 4.3%. Mortality rate was 10.7%, and colonized neonates did not develop HAIs. The most significant period for MDR identification through SCs occurred during the 2nd and 3rd weeks of hospitalization (80.9%). Clinical cultures and medical record reports did not confirm subsequent infectious episodes. SCs demonstrated high value in detecting E. cloacae NDM colonization in the NICU, reinforcing the importance of precise laboratory identification and continuous microbiological surveillance. Rapid response enabled timely interventions, such as implementation of contact precautions, environmental control, and revision of care protocols, underscoring the importance of this strategy in controlling MDR dissemination and preventing HAIs in neonatology.