Endoscope linked to hospital outbreak of multidrug-resistant organisms

An epidemiologic investigation by researchers from the University of Pittsburgh has found that an outbreak of multidrug-resistant organisms (MDROs) in hospital patients was linked to contamination of a single, defective bronchoscope, according to a study in Infection Control and Hospital Epidemiology.

The outbreak was discovered in November 2014, when a cluster of patients with bronchoscopically obtained clinical cultures positive for carbapenem-resistant Klebsiella pneumoniae (CR-KP) and multidrug-resistant P aeruginosa (MDR-PA) was identified in the medical intensive care unit (MICU) at University of Pittsburgh Medical Center-Presbyterian Hospital. Of the nine bronchoscopes used in the MICU, only one (named B1) was positive for CR-KP and MDR-PA. To determine the link between bronchoscope B1 and the outbreak, investigators performed molecular typing and WGS on isolates from the patients and the device.

A total of 33 case patients with cultures positive for CR-KP and MDR-PA were identified from July 2014 to December 2014; of these patients, 23 (69.7%) were exposed to bronchoscope B1. Molecular testing and WGS confirmed that isolates from bronchoscope B1 and 19 of the patients were genetically related, providing strong evidence for horizontal bacterial transmission. Ten of the 19 patients were classified as belonging to a “pseudo-outbreak” that occurred because of contamination of patient specimens as they were being withdrawn from the bronchoscope.

Upon removal of B1 from service, the number of patients with newly detected CR-KP or MDR-PA decreased. Borescopy revealed a luminal defect that may have contributed to the establishment of biofilm and subsequent contamination, despite compliance with the manufacturer’s recommended reprocessing procedures.

The authors of the study conclude, “In addition to adhering to endoscope reprocessing guidelines, hospital epidemiology programs should prioritize thorough periodic maintenance of endoscopic devices and emphasize scrutiny of endoscopic-derived culture data as an important intervention to hasten recognition of endoscope-associated outbreaks.”

Source: CIDRAP