Abstract
An outbreak of Pseudomonas aeruginosa producing metallo–β-lactamase (MBLPA) in the hematology ward was controlled after use of toilet seats with bidet functions was terminated. Twenty four strains of MBLPA were identified from hospitalized patients in the hematology unit from January 2007 to December 2012. Multidisciplinary interventions including routine active surveillance, strengthening contact precautions, and analysis of risk factors for MBLPA were performed. However, new MBLPA infections continued to be identified after institution of infection control strategies. During the outbreaks, environmental surveys were conducted and 6 MBLPA isolates were detected from the spray nozzles of the toilet seats with bidet functions in this ward. Twenty four MBLPA isolates from the patients and 6 from spray nozzles were analyzed for chromosomal DNA typing by PCR–based ORF typing (POT). All 24 MBLPAs from the patients and all 6 isolates from nozzles had the same POTS patterns (Pot No. 644–41). Use of the toilet seats with bidet functions was discontinued during January to September 2013 and only 1 new isolate was identified in this period. Use of the toilet seats with bidet functions in October 2013 and 2 new MBLPAs were identified in only 3 months. Therefore, use of toilet seats with bidet functions was again terminated since January 2014 and occurrence of new isolates decreased again (1 isolate during 12 months). Incidence of MBLPA isolate per 1000 patient-days was 0.49 in the period of use of the toilet seats with bidet functions and 0.10 in the period of no use. In conclusion, use of toilet seats with bidet functions in the hematological unit is highly suspected as a risk factor for transmission of MBL producing Pseudomonas aeruginosa.
