Early Detection and Effective Containment of a Carbapenem-Resistant Klebsiella pneumoniae epidemic  in a Neonatal Intensive Care Unit: Insights from Whole-Genome Sequencing and Infection Control Measures
Carbapenem-resistant Klebsiella pneumoniae (CRKP) is characterized by high transmission rates and a high mortality rate. Its isolation rate in neonatal wards has shown an upward trend annually, posing a major threat to the survival of children and newborns. This study reports the early detection and successful control of a nosocomial infection caused by carbapenem-resistant Klebsiella pneumoniae in the neonatal intensive care unit at Nanjing, China, from February to March 2024.Methods: From February to March 2024, seven Klebsiella pneumoniae (K. pneumoniae) isolates from five newborns at a tertiary hospital in Nanjing, China, underwent analysis using the VITEK 2 Compact system, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), whole genome sequencing (WGS), and multi-locus sequence typing (MLST) to compare the antimicrobial susceptibility, virulence, and resistance genes of these strains. This study assessed their clonal relationships and implemented scientifically sound measures for controlling this nosocomial infection epidemic.Results: Among 5 pediatric patients carrying K. pneumoniae, 3 were confirmed as nosocomial infection cases. One patient died from multiple organ failure, while the other two recovered and were discharged. All isolates were CRKP with MLST typing ST11. They harbored the blaKPC-2 and blaSHV beta-lactamase genes alongside high-virulence genes such as mrkD, entB, and ybt. Genome-wide SNP variation grouped the seven strains into three evolutionary clades. Upon suspicion of infection, hospital authorities immediately implemented stringent infection control measures, bringing the transmission under control within a short period. No new infection cases have been reported since April 2024.Conclusions: This hospital-acquired infection was caused by highly drug-resistant CRKP. Rapid containment was achieved through the hospital's implementation of strict surveillance measures and multidisciplinary management. It also underscores the importance of whole-genome sequencing (WGS) in epidemiological studies of infections and transmission control.