Analysis of a Klebsiella pneumoniae ST134 outbreak: from basic microbiology to whole-genome sequencing in a tertiary hospital
I V Diaz-Jiménez, D Manzano-Arredondo, C Ibanes-Gutiérrez, J A Ferrer-Martínez, A G González-Garay, P Saltigeral-Simental, M Macías-ParraAbstract
Background
Klebsiella pneumoniae is a Gram-negative rod related with important healthcare associated outbreaks due to its high dissemination capacity and multidrug resistance (MDR). This study, conducted at the National Institute of Pediatrics in Mexico, aimed to analyze an outbreak of MDR K. pneumoniae from May to August 2024.
Methods
The outbreak was investigated in a 290-bed tertiary pediatric hospital as a significant increase in MDR K. pneumoniae was identified, noting a particular rise in the detection of two carbapenemases (OXA-48 and NDM). Isolates were from tracheal aspirates and bronchoalveolar lavages. The analysis included phenotypic sensitivity testing, real-time polymerase chain reaction to detect resistance genes, and next-generation sequencing (NGS) to characterize the genomic profile. Epidemiological data were collected to establish temporal and spatial relationships between cases.
Results
Nine patients with a median age of 4.2 years were confirmed as infected or colonized by K. pneumoniae identified as ST134 (Figure 1). Resistance mechanisms identified included carbapenemases OXA-181 and NDM-1, as well as AmpC beta-lactamases and efflux pumps, sensitivity to tigecycline and colistin was maintained. Epidemiological analysis revealed close temporal and spatial links between cases (Figure 2), with most transmissions occurring in the Pediatric Intensive Care Unit (PICU). Universal contact precautions in PICU, cohort isolation, environmental cultures, and enhanced cleaning protocols, were promptly implemented to contain the outbreak. Environmental sampling identified the pathogen on two high-contact surfaces. Containment measures effectively halted the outbreak. There were no deaths attributable to the K. pneumoniae ST134.
Conclusions
This is the first reported outbreak of K. pneumoniae ST134 in Latin America. Rapid identification of the outbreak, supported by NGS, enabled timely implementation of infection prevention and control measures, preventing further spread within the hospital. This study highlights the importance of integrating molecular techniques into routine surveillance to address the increasing threat of MDR pathogens. Effective containment strategies and continuous surveillance are essential for preventing endemicity and improving patient outcomes.