Identification and Characterization of Vancomycin-resistant
Enterococcus species Frequently Isolated from Laboratory
Mice |
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Authors: | Hitoki Yamanaka Toshikazu Takagi Makiko Ohsawa Naoto Yamamoto Noriaki Kubo Takahira Takemoto Shoko Sasano Ritsuko Masuyama Kazutaka Ohsawa |
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Institution: | 1) Division of Comparative Medicine, Center for Frontier Life Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan;2) Department of Molecular Bone Biology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan |
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Abstract: | To determine the prevalence of drug resistant bacteria colonizing laboratory mice, we
isolated and characterized vancomycin-resistant Enterococcus 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
E. gallinarum and 5 isolates of E. casseliflavus
possessing the vanC1 and vanC2/3 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 (ace,
asa, cylA, efaA,
esp, and gelE) and secretion of gelatinase and hemolysin
were not detected in all isolates, 23 of 24 isolates including the isolates of E.
casselifalvus 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. |
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Keywords: | ATP laboratory mice prevalence vancomycin-resistant Enterococcus virulence factor |
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