Risk Assessment After a Severe Hospital-Acquired Infection Associated With Carbapenemase-Producing Pseudomonas aeruginosa

Abstract

Importance: Resistance of gram-negative bacilli to carbapenems is rapidly emerging worldwide. In 2016, the World Health Organization defined the hospital-built environment as a core component of infection prevention and control programs. The hospital-built environment has recently been reported as a source for outbreaks and sporadic transmission events of carbapenemase-producing gram-negative bacilli from the environment to patients.

Objective: To assess risk after the identification of an unexpected, severe, and lethal hospital-acquired infection caused by carbapenemase-producing Pseudomonas aeruginosa in a carbapenemase-low endemic setting.

Design, settings, and participants: A case series study in which a risk assessment was performed on all 11 patients admitted to the combined cardiothoracic surgery and pulmonary diseases ward and the hospital-built environment in the Radboud University Medical Center, the Netherlands, in February 2018.

Exposures: Water and aerosols containing carbapenemase-producing (Verona integron-mediated metallo-β-lactamase [VIM]) P aeruginosa.

Main outcomes and measures: Colonization and/or infection of patients and/or contamination of the environment after the detection of 1 patient infected with carbapenemase-producing (VIM) P aeruginosa.

Results: A total of 5 men (age range, 60-84 years) and 6 women (age range, 55-74 years) were admitted to the combined cardiothoracic surgery and pulmonary diseases ward. The risk assessment was performed after carbapenemase-producing (VIM) P aeruginosa was unexpectedly detected in a man in his early 60s, who had undergone a left-sided pneumonectomy and adjuvant radiotherapy. No additional cases (colonization or infection) of carbapenemase-producing (VIM) P aeruginosa were detected. Plausible transmission of carbapenemase-producing P aeruginosa from the hospital environment to the patient via the air was confirmed by whole-genome sequencing, which proved the relation of Pseudomonas strains from the patient, the shower drains in 8 patient rooms, 1 sink, and an air sample.

Conclusions and relevance: This study suggests that rethinking the hospital-built environment, including shower drains and the sewage system, will be crucial for the prevention of severe and potential lethal hospital-acquired infections.

Figure 1.. Whole-Genome Sequencing, Minimum Spanning Tree

Strains of Pseudomonas aeruginosa from the patient, the shower drains, 1 sink, and the air sample are identical with limited single-nucleotide polymorphisms (SNPs; numbers between circles) difference (range, 1-12 SNPs) in comparison with 10 reference strains (≥17 973 SNPs).

Figure 2.. Schematic Ward Map With Sewage Systems and Carbapenemase-Producing Pseudomonas aeruginosa–Positive Shower Drains in Patient Rooms

Schematic ward map illustrates the clustering of carbapenemase-producing P aeruginosa–positive shower drains in patient rooms (P50-P60) and carbapenemase-producing P aeruginosa–negative shower drains in patient rooms in relation to the sewage collection points. The patient was admitted to room P54 before undergoing the Clagett open-window thoracostomy; this room had negative results for P aeruginosa in the initial environmental screening. After surgery the patient was admitted to room P56, where the shower drain had positive results for P aeruginosa. S indicates shower.