AUTHOR=Harada Kazuki , Shimizu Takae , Mukai Yujiro , Kuwajima Ken , Sato Tomomi , Usui Masaru , Tamura Yutaka , Kimura Yui , Miyamoto Tadashi , Tsuyuki Yuzo , Ohki Asami , Kataoka Yasushi 

TITLE=Phenotypic and Molecular Characterization of Antimicrobial Resistance in Klebsiella spp. Isolates from Companion Animals in Japan: Clonal Dissemination of Multidrug-Resistant Extended-Spectrum β-Lactamase-Producing Klebsiella pneumoniae

JOURNAL=Frontiers in Microbiology

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2016.01021

DOI=10.3389/fmicb.2016.01021

ISSN=1664-302X

ABSTRACT=<p>The emergence of antimicrobial resistance in <italic>Klebsiella</italic> spp., including resistance to extended-spectrum cephalosporins (ESC) and fluoroquinolones, is of great concern in both human and veterinary medicine. In this study, we investigated the prevalence of antimicrobial resistance in a total of 103 <italic>Klebsiella</italic> spp. isolates, consisting of <italic>Klebsiella pneumoniae</italic> complex (KP, <italic>n</italic> = 89) and <italic>K. oxytoca</italic> (KO, <italic>n</italic> = 14) from clinical specimens of dogs and cats in Japan. Furthermore, we characterized the resistance mechanisms, including extended-spectrum β-lactamase (ESBL), plasmid-mediated AmpC β-lactamase (PABL), and plasmid-mediated quinolone resistance (PMQR); and assessed genetic relatedness of ESC-resistant <italic>Klebsiella</italic> spp. strains by multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). Antimicrobial susceptibility testing demonstrated that resistance rates to ampicillin, cephalothin, enrofloxacin, ciprofloxacin, trimethoprim/sulfamethoxazole, cefotaxime, gentamicin, tetracycline, chloramphenicol, amoxicillin-clavulanic acid, and cefmetazole were 98.1, 37.9, 37.9, 35.9, 35.0, 34.0, 31.1, 30.1, 28.2, 14.6, and 6.8%, respectively. Phenotypic testing detected ESBLs and/or AmpC β-lactamases in 31 of 89 (34.8%) KP isolates, but not in KO isolates. Resistances to 5 of the 12 antimicrobials tested, as well as the three PMQRs [<italic>qnrB, qnrS</italic>, and <italic>aac(6</italic>′<italic>)-Ib-cr</italic>], were detected significantly more frequently in ESBL-producing KP, than in non-ESBL-producing KP and KO. The most frequent ESBL was CTX-M-15 (<italic>n</italic> = 13), followed by CTX-M-14 (<italic>n</italic> = 7), CTX-M-55 (<italic>n</italic> = 6), SHV-2 (<italic>n</italic> = 5), CTX-M-2 (<italic>n</italic> = 2), and CTX-M-3 (<italic>n</italic> = 2). Based on the <italic>rpoB</italic> phylogeny, all ESBL-producing strains were identified as <italic>K. pneumoniae</italic>, except for one CTX-M-14-producing strain, which was identified as <italic>K. quasipneumoniae</italic>. All of AmpC β-lactamase positive isolates (<italic>n</italic> = 6) harbored DHA-1, one of the PABLs. Based on MLST and PFGE analysis, ST15 KP clones producing CTX-M-2, CTX-M-15, CTX-M-55, and/or SHV-2, as well as KP clones of ST1844-CTX-M-55, ST655-CTX-M-14, and ST307-CTX-M-15, were detected in one or several hospitals. Surprisingly, specific clones were detected in different patients at an interval of many months. These results suggest that multidrug-resistant ESBL-producing KP were clonally disseminated among companion animals via not only direct but also indirect transmission. This is the first report on large-scale monitoring of antimicrobial-resistant <italic>Klebsiella</italic> spp. isolates from companion animals in Japan.</p>