Scanning electron micrograph of Escherichia coli. Credit: National Institute of Allergy and Infectious Diseases, National Institutes of Health
In 2017, a medical center in Japan traced an outbreak of the multidrug-resistant bacteria Carbapenemase-producing Enterobacterales (CPE) to the facility’s sinks. After a few months, in an attempt to rein in the outbreak, the medical center replaced all the sicks in the pediatric ward.
But the contamination continued.
While the hospital was able to stop CPE contamination 4 months later using intense infection control protocols, the outbreak was eye-opening as well as educational, ultimately indicating that pathogen transmission may be possible via drains and connected plumbing.
“Our experience highlights the importance of focusing on sinks and other water-related areas in hospital wards, as these are critical for CPE transmission and therefore major fronts in the fight against antibiotic resistance,” said corresponding author Sadako Yoshizawa, MD, deputy director of clinical laboratory at Toho University Omori Medical Center.
Toho University Omori Medical Center is a 916-bed academic medical center with 55 pediatric inpatient beds. In June 2016, CPE was detected in a 1-year-old boy hospitalized with cardiac disease. This infection triggered an outbreak, starting in March 2017 and ending in October 2017. The outbreak involved a total of 19 pediatric patients.
During the outbreak, sampling identified nine sinks contaminated with CPE, including six in hospital rooms and three more in a nurse center, a waste room and an ice machine. The CPE-positive sinks were all found in rooms where CPE-positive patients had been treated. In rooms with CPE-negative patients, no sink contamination was detected.
The biological mechanism that confers multidrug resistance can be passed from one bacterial species to another, contributing to the growing epidemic of antimicrobial resistance. Thus, an outbreak of one CPE species in a hospital has the potential to turn into an outbreak involving many species, making it that much more difficult and dangerous.
As part of the infection control process, researchers performed genome analysis to identify the specific resistance mechanisms found in the bacterial strains, which included Klebsiella variicola, Klebsiella quasipneumoniae and E.coli, among others. According to the study results, published in The American Journal of Infection Control, all the samples showed identical DNA sequences except one—supporting the idea that the resistance mechanism could have been passed from one bacterial species to another within the hospital.
Ongoing for four months, the decision was made to replace all the sinks in the pediatric ward in June 2017. The new sinks were thoroughly disinfected with hydrogen peroxide; however, CPE contamination continued.
The infection prevention team then turned to other measures, including recommending hand disinfection after using sinks, introducing disposable tools for cleaning sinks, prohibiting mouth-washing with sink water, enacting disinfection and drying procedures to any items exposed to sink water, and more.
Finally, in October 2017, no further CPE contamination was identified in patient samples or environmental surveillance.