Identification and Characterization ofVancomycin-resistant <i>Enterococcus</i> species Frequently Isolated from Laboratory Mice
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To determine the prevalence of drug resistant bacteria colonizing laboratory mice, we isolated and characterized vancomycin-resistant <i>Enterococcus</i> species (VRE) from commercially available mice. A total of 24 VRE isolates were obtained from 19 of 21 mouse strains supplied by 4 commercial breeding companies. Of these, 19 isolates of <i>E. gallinarum</i> and 5 isolates of <i>E. casseliflavus</i> possessing the <i>vanC1</i> and <i>vanC2/3</i> genes intrinsically, exhibited intermediate resistance to vancomycin respectively. In addition, these isolates also exhibited diverse resistant patterns to erythromycin, tetracycline, and ciprofloxacin, whereas the use of antibiotics had not been undertaken in mouse strains tested in this study. Although 6 virulence-associated genes (<i>ace</i>, <i>asa</i>, <i>cylA</i>, <i>efaA</i>, <i>esp</i>, and <i>gelE</i>) and secretion of gelatinase and hemolysin were not detected in all isolates, 23 of 24 isolates including the isolates of <i>E. casselifalvus</i> secreted ATP into culture supernatants. Since secretion of ATP by bacteria resident in the intestinal tract modulates the local immune responses, the prevalence of ATP-secreting VRE in mice therefore needs to be considered in animal experiments that alter the gut microflora by use of antibiotics.
- Experimental Animals
Experimental Animals 63(3), 297-304, 2014
Japanese Association for Laboratory Animal Science