Antibiotic resistance patterns and genetic relatedness of Enterococcus faecalis and E. faecium isolated from military working dogs in Korea
Kiman Bang1,†, Jae-Uk An1,†, Woohyun Kim1, Hee-Jin Dong1, Junhyung Kim1, Seongbeom Cho1,*
1BK21 PLUS Program for Creative Veterinary Science Research, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea
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The first two authors contributed equally to this work.
Received: January 19, 2016; Revised: June 14, 2016; Accepted: August 4, 2016; Published online: September 1, 2016.
Enterococcus spp. are normally present in the gastrointestinal tracts of animals and humans, but can cause opportunistic infections that can be transmitted to other animals or humans with integrated antibiotic resistance. To investigate whether this is a potential risk in military working dogs (MWDs), we analyzed antibiotic resistance patterns and genetic relatedness of Enterococcus spp. Isolated from fecal samples of MWDs of four different age groups. The isolation rates of Enterococcus spp., and specifically of E. faecalis and E. faecium, were 87.7% (57/65), 59.6% (34/57), and 56.1% (32/57), respectively, as determined by bacterial culture and multiplex PCR. The isolation rate of E. faecalis gradually decreased with age (puppy, 100%; adolescent, 91.7%; adult, 36.4%; and senior, 14.3%). Rates of resistance to the antibiotics ciprofloxacin, gentamycin, streptomycin, sulfamethoxazole/trimethoprim, imipenem, and kanamycin among Enterococcus spp. increased in adolescents and adults and decreased in senior dogs, with some isolates showing three different antibiotic resistance patterns. We also found indistinguishable PFGE patterns between different age groups. These results suggest that Enterococcus is horizontally transferred, irrespective of age. As such, surveillance studies should be periodically carried out to monitor changes in antibiotic resistance that may necessitate modification of antibiotic regimens to manage antibiotic resistance transmission.
Keywords: Enterococcus faecalis, Enterococcus faecium, PFGE, antibiotic resistance, large-breed dog

© 2016 The Korean Society of Veterinary Science.