Antimicrobial resistance profiles of vancomycin-resistant Enterococcus species isolated from laboratory mice
- Author:
Hitoki YAMANAKA
1
;
Ryuki KADOMATSU
;
Toshikazu TAKAGI
;
Makiko OHSAWA
;
Naoto YAMAMOTO
;
Noriaki KUBO
;
Takahira TAKEMOTO
;
Kazutaka OHSAWA
Author Information
- Publication Type:Original Article
- Keywords: Antibiotic resistance; Enterococcus; laboratory mice
- MeSH: Amino Acid Substitution; Animals; Anti-Bacterial Agents; Breeding; Ciprofloxacin; DNA Gyrase; DNA Topoisomerase IV; Drug Resistance, Microbial; Enterococcus; Erythromycin; Fluoroquinolones; Mice; Tetracycline; Vancomycin
- From:Journal of Veterinary Science 2019;20(2):e13-
- CountryRepublic of Korea
- Language:English
- Abstract: Isolates of 24 enterococci, 5 Enterococcus casseliflavus and 19 Enterococcus gallinarum, possessing vanC genes and showing low-level resistance to vancomycin were obtained from mice from commercial mouse breeding companies. Since some of these isolates showed resistance to other antibiotics, the purpose of this study was to clarify the resistant profiles of these isolates. One E. casseliflavus isolate showed resistance to erythromycin with a minimal inhibitory concentration (MIC) of 8 μg/mL and also showed apparent resistance to fluoroquinolones with an MIC of 32 μg/mL for ciprofloxacin. The MICs of 2 other fluoroquinolone-resistant E. casseliflavus and E. gallinarum isolates were 3 and 6 μg/mL, respectively. These 3 resistant isolates showed an absence of macrolide- and fluoroquinolone-resistant genes, including amino acid substitutions in the quinolone resistance determining regions of DNA gyrase and topoisomerase IV. Resistance to tetracycline was detected in 2 E. gallinarum isolates that were highly resistant, exhibiting MICs of 48 and 64 μg/mL and possessing tet(O) genes. The results indicate that antibiotic-resistant enterococci are being maintained in some laboratory mouse strains that have never been treated with an antibiotic.
