Bronchoscope: an important and easily overlooked vector of clinical infection with Klebsiella pneumoniae.

OBJECTIVE

To investigate the role of bronchoscopes in a Pediatric Intensive Care Unit (PICU) carbapenem-resistant Klebsiella pneumoniae (CRKP) outbreak and analyze the biological characteristics of the isolated strains, providing evidence for nosocomial infection prevention.

METHODS

A CRKP infection outbreak in a PICU was investigated. Four CRKP strains were isolated from the bronchoalveolar lavage fluid of infected patients, and one CRKP strain was isolated from the shared bronchoscope used for these patients. Antimicrobial susceptibility testing was performed to determine the drug resistance profile of the strains. Genotypic analysis was conducted to detect the presence of antimicrobial resistance genes and virulence-associated genes. Average nucleotide identity (ANI) and sequence typing (ST) were used to assess the homology of the five isolated CRKP strains. Silver staining was adopted to compare the biofilm formation capabilities of the bronchoscope-isolated strain, patient-isolated strains and the standard control strain.

RESULTS

All 5 CRKP isolates were fully resistant to cephalosporins, carbapenems and other agents, but susceptible to levofloxacin, trimethoprim/sulfamethoxazole and tigecycline, and all carried bla NDM-1, mrkD and other resistance/virulence genes. Homology analysis confirmed all strains belonged to the same clonal lineage (ST1697, ANI 99.97%-99.99%). The bronchoscope-isolated strain had the strongest biofilm-forming capacity, followed by patient isolates, all superior to the standard control strain.

CONCLUSION

Contaminated bronchoscopes are the transmission vector of this monoclonal CRKP outbreak in PICU. The enhanced biofilm-forming ability of ST1697 CRKP facilitates its persistence and transmission, highlighting the necessity of strict adherence to bronchoscope disinfection and quality control to prevent hospital-acquired infections.