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

Enterobacteriaceae producing extended spectrum β-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 blaCTX-M-1, -3, -15, -2, -14, -27, and mutants of blaSHV-1 were detected. Among them, blaCTX-M-15 (33.3%), blaCTX-M-14 (27.8%) and blaCTX-M-27 (33.3%) were dominant in the E. coli isolates, whereas a blaSHV 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 blaCTX-M, and blaSHV 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 blaCTX-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.

Nakama R ，Shingaki A ，Miyazato H ，Higa R ，Nagamoto C ，Hamamoto K ，Ueda S ，Hachiman T ，Touma Y ，Miyagi K ，Kawahara R ，Toyosato T ，Hirai I ... -  《-》

Prevalence of ESBL/AmpC genes and specific clones among the third-generation cephalosporin-resistant Enterobacteriaceae from canine and feline clinical specimens in Japan.

In recent years, besides the widespread occurrence of extended-spectrum β-lactamase (ESBL)- and/or plasmid-mediated AmpC (pAmpC)-producing Enterobacteriaceae in both healthcare and community settings of humans, the third-generation cephalosporin (3GC)-resistant microbes have also been reported from companion animals worldwide. Here, we characterized ESBL- and/or pAmpC-producing Enterobacteriaceae clinical isolates from companion animals. Among the 487 clinical isolates mainly from urine of dogs and cats between May and September 2016, 104 non-repetitive isolates were resistant to the 3GC, and they consisted of 81 of 381 (21.3%) Escherichia coli, 21 of 50 (42.0%) Klebsiella pneumoniae, and 2 of 56 (3.6%) Proteus mirabilis isolates. In the 81 E. coli, the predominant bla genes were blaCTX-M-27 and blaCMY-2 (n = 15 each), followed by blaCTX-M-15 (n = 14), blaCTX-M-14 (n = 10), and blaCTX-M-55 (n = 5). In 21 K. pneumoniae, 10 bla gene types including blaCTX-M-15 (n = 4), blaCTX-M-2 (n = 4), and blaCTX-M-14 (n = 3) were found. The blaCTX-M-2 was identified in 2 P. mirabilis. Twenty-four of the 42 E. coli belonging to phylogroup B2 were O25b-ST131 clone, mostly associated with uropathogenic E. coli pathotype, and 22 isolates of this clone were identified as specific H30R subclone. High prevalence of the blaCTX-M-27-harboring isolates were noted among the H30R/non-Rx lineage (13/19, 68.4%) (p <  0.05). The genetic environment of blaCTX-M-27 of most isolates of this lineage was identical to that of human isolates, but unique flanking genetic structures were also identified. Newly emerging virulent lineage B2-non-O25b-ST1193 was also confirmed in 5 isolates. The fosA3 and/or armA genes were detected in E. coli and K. pneumoniae isolates. These data suggest that companion animals serve as a potential reservoir of antimicrobial resistant E. coli and K. pneumoniae. This also has considerable veterinary importance, since urinary tract infections are an important disease causing therapeutic challenges worldwide.

Maeyama Y ，Taniguchi Y ，Hayashi W ，Ohsaki Y ，Osaka S ，Koide S ，Tamai K ，Nagano Y ，Arakawa Y ，Nagano N ... -  《-》

Characterization of CTX-M type ESBL-producing Enterobacteriaceae isolated from asymptomatic healthy individuals who live in a community of the Okinawa prefecture, Japan.

This study was performed to characterize CTX-M type extended spectrum β-lactamase (ESBL)-producing Enterobacteriaceae carriage in asymptomatic health individuals, which has not been well investigated, in a community of the Okinawa prefecture, Japan. Fecal samples were voluntary collected from asymptomatic healthy individuals who were going to take a routine medical checkup. The collected fecal samples were inoculated on MacConkey agar supplemented with 2 μg/ml of cefotaxime and incubated at 37 °C. Randomly selected three lactose-fermented colonies per each sample were analyzed. Genetic relatedness among the CTX-M type ESBL-producing Enterobacteriaceae isolates were performed by pulsed-field gel electrophoresis (PFGE) after confirmation of ESBL phenotype and determination of bacterial species. Location of blaCTX-M was confirmed by S1-PFGE, I-CeuI-PFGE and the Southern blotting hybridization. ESBL-producing Enterobacteriaceae was isolated from 32 (12.2%) of the collected 263 fecal samples, and 96 ESBL-producing Enterobacteriaceae isolates were obtained. CTX-M type ESBL-producing Escherichia coli B2 were major (67 isolates, 72.0%) and 40 (59.7%) of the 67 CTX-M type ESBL -producing E. coli B2 were E. coli B2-ST131. Three CTX-M type ESBL-producing E. coli B2-ST131 isolates from asymptomatic healthy individuals showed similar PFGE band patterns as five CTX-M type ESBL -producing E. coli B2-ST131 isolates from a hospital locates in the same area of the target community. Chromosomally-transferred blaCTX-M was observed in 10.0% of the examined CTX-M type ESBL-producing Enterobacteriaceae isolates. We report current situation CTX-M type ESBL-producing Enterobacteriaceae carriage in asymptomatic healthy individuals of the Okinawa prefecture, Japan. In addition, our results indicated that worldwide distributed CTX-M type ESBL-producing E. coli B2-ST131 has been spread in a community. Therefore monitoring of ESBL-producing Enterobacteriaceae in healthy individuals is important.

Higa S ，Sarassari R ，Hamamoto K ，Yakabi Y ，Higa K ，Koja Y ，Hirai I ... -  《-》

In vitro activity of flomoxef and comparators against Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis producing extended-spectrum β-lactamases in China.

The objective of this study was to better understand the in vitro activity of flomoxef against clinical extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae. A total of 401 ESBL-producing isolates, including 196 Escherichia coli, 124 Klebsiella pneumoniae and 81 Proteus mirabilis, were collected consecutively from 21 hospitals in China in 2013. Minimum inhibitory concentrations (MICs) were determined by broth microdilution methods. Phenotypic identification of ESBL production was detected as recommended by the Clinical and Laboratory Standards Institute (CLSI). ESBL genes were detected by PCR and sequencing. Flomoxef, doripenem, meropenem, ertapenem, cefmetazole and piperacillin/tazobactam exhibited good activity against ESBL-producing isolates, with susceptibility rates >90%. Tigecycline showed good activity against E. coli and K. pneumoniae (100% and 97.6%, respectively). Cefotaxime and cefepime showed very low activities against ESBL-producing isolates, with susceptibility rates of 0-0.8% and 1.0-13.6%, respectively. blaCTX-M were the major ESBL genes, with occurrence in 99.5% of E. coli, 91.1% of K. pneumoniae and 97.5% of P. mirabilis. blaCTX-M-14 was the predominant ESBL gene, detected in 46.9% (188/401) of the isolates, followed by blaCTX-M-15 (21.4%), blaCTX-M-55 (17.2%), blaCTX-M-65 (12.7%) and blaCTX-M-3 (6.7%). Flomoxef exhibited excellent activity against the different CTX-M-type ESBL-producing isolates, with MIC50 and MIC90 values of 0.064-0.125μg/mL and 0.25-0.5μg/mL, respectively. Against the isolates solely producing CTX-M-14, -15, -55, -3 or -65, flomoxef showed susceptibility rates of 98.6%, 98.0%, 98.1%, 100.0% and 97.4%, respectively. In conclusion, flomoxef showed good activity against ESBL-producing Enterobacteriaceae and may be a choice to treat infections caused by these isolates in China.

Yang Q ，Zhang H ，Cheng J ，Xu Z ，Xu Y ，Cao B ，Kong H ，Ni Y ，Yu Y ，Sun Z ，Hu B ，Huang W ，Wang Y ，Wu A ，Feng X ，Liao K ，Shen D ，Hu Z ，Chu Y ，Lu J ，Su J ，Gui B ，Duan Q ，Zhang S ，Shao H ... -  《-》

Characterization of Enterobacteriaceae isolates obtained from a tertiary care hospital in Mexico, which produces extended-spectrum β-lactamase.

Morfín-Otero R ，Mendoza-Olazarán S ，Silva-Sánchez J ，Rodríguez-Noriega E ，Laca-Díaz J ，Tinoco-Carrillo P ，Petersen L ，López P ，Reyna-Flores F ，Alcantar-Curiel D ，Garza-Ramos U ，Garza-González E ... -  《-》