LAUSR

ABSTRACT The occurrence of heavy metal resistance genes in multiresistant Enterobacteriaceae possessing blaNDM-1 or blaCTX-M-15 genes was examined by PCR and pulsed-field gel electrophoresis with S1 nuclease. Compared with clinical susceptible isolates (10.0% to 30.0%), the pcoA, merA, silC, and arsA genes occurred with higher frequencies in blaNDM-1-positive (48.8% to 71.8%) and blaCTX-M-15-positive (19.4% to 52.8%) isolates, and they were mostly located on plasmids. Given the high association of metal resistance genes with multidrug-resistant Enterobacteriaceae, increased vigilance needs to be taken with the use of heavy metals in hospitals and the environment.