Current status of extended spectrum beta-lactamase-producing Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis in Okinawa prefecture, Japan

摘要

Enterobacteriaceae producing extended spectrum beta-lactamase (ESBL) are distributed worldwide. In this study, 114 ESBL-producing Enterobacteriaceae were isolated by analyzing 1672 clinical isolates of Enterobacteriaceae collected from an Okinawa prefectural hospital in Japan between June 2013 and July 2014. The overall prevalence of ESBL-producing Enterobacteriaceae was 6.8%; the prevalence of different bacterial species among the ESBL-producing isolates was as follows: 11.5% Escherichia coli (90 of 783 isolates), 6.2% Klebsiella pneumoniae (19 of 307 isolates), and 11.1% Proteus mirabilis (5 of 45 isolates). The ESBL types bla(CTX-M-1, -3, -15, -2, -14, -27), and mutants of bla(SHV-1) were detected. Among them, bla(CTX-M-15) (33.3%), bla(CTX-M-14) (27.8%) and bla(CTX-M-27) (33.3%) were dominant in the E. coli isolates, whereas a bla(SHV) mutant which possessed four mutations (Tyr7Phe, Leu35Gln, Gly238Ser and Glu240Lys) in the amino acid sequence of SHV-1 dominated in the K. pneumoniae isolates (11 of 19, 57.9%). The pandemic E. coli ST131 clone was found to constitute 3.3% of the overall examined isolates and 62.2% of the ESBL-producing E. coli isolates. Our results suggest that the genetic combination of bla(CTX-M), and bla(SHV) and antibiotics-resistant profile were different from that in other regions such as other areas of Japan, Asia, Europe, and North America, especially in the ESBL-producing K. pneumoniae isolates and in the E. coli B2-O25b-ST131 isolates possessing bla(CTX-M-15) (40.7% of the E. coli B2-O25b-ST131 isolates). Taken together, our results indicate that the ESBL-producing Enterobacteriaceae in Okinawa, Japan, might be of a unique nature. (C) 2016, Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.