No regional spread of vancomycin-resistant enterococci with vanA or vanB in Kitakyushu, Japan

Outbreaks of vancomycin-resistant enterococci (VRE) infection occur sporadically in Japan, and their frequency has been gradually increasing. We experienced a nosocomial outbreak of VRE in two hospitals in the city of Kitakyushu, and the spread of VRE strains was suspected in this area. To examine the prevalence rate of infection and colonization of VRE in Kitakyushu, we screened a total of 24297 clinical samples from patients in hospitals and clinics in Kitakyushu from October through December 2002 for VRE. The isolates screened as positive for VRE accounted for 2.3% (566/24 297) of the tested clinical samples. Polymerase chain reaction (PCR) analyses for vanA, vanB, vanC1, and vanC2/3 were performed to confirm the screening test results. Neither vanA nor vanB genes were detected in any isolates. The 265 vanC1-positive isolates were Enterococcus gallinarum, and the 150 vanC2/3-positive isolates were E. casseliflavus. Other Enterococcus species were negative in this PCR-detection test. In this study, the PCR procedure was considered reliable and successful because although neither vanA nor vanB was detected, vanC1 and vanC2/3 were completely detectable. Therefore, we concluded that the regional spread of VRE with vanA and vanB had not occurred in Kitakyushu in 2002. In the near future, the prevalence of VRE with vanA or vanB is likely to increase in Japan, as it has in other countries. We should continue to find and prevent nosocomial outbreaks of infection and colonization by VRE.