Prevalence of virulence and resistance to antibiotics in pathogenicenterococci isolated from mastitic cows

The Journal of Veterinary Medical Science

Wei KAN¹  Youji MA¹  Yong ZHANG²  Quanwei ZHANG³  Shubao HOU⁴  Xiaohu WU⁴  Xingxu ZHAO⁴ 

[1] Technology, GansuAgricultural University, No. 1, Yingmen county, Anning district, Lanzhou 730070,China;College of Animal Science &College of Life Science &College of Veterinary Medicine, Gansu AgriculturalUniversity, No. 1, Yingmen county, Anning district, Lanzhou 730070,China;No. 498, Helanshanxilu, Department of Agriculture andHusbandry, Ningxia Hui Autonomous Region, Yinchuan 750021, China

关键词: antibiotic resistance;    pathogenic enterococci;    prevalence;    virulence;   

DOI  :  10.1292/jvms.15-0718

学科分类：兽医学

来源: Japanese Society of Veterinary Science

【 摘 要 】

The prevalence of enterococci was examined in 280 milk samples collected from dairycattle diagnosed with mastitis in three provinces of western China. Sixty strains ofenterococci were isolated, and the species were determined based on their biochemicalcharacters and 16S rRNA sequences. Resistance to seven antibiotic agents, frequency ofseven virulence genes and pathogenicity in Kunming mice were tested toevaluate biological risks. The correlation between the number of virulence genes andpathogenicity in Kunming mice was also evaluated. The 60 isolates wereallocated to Enterococcus hirae (68.3%), E. faecium(25.0%), E. mundtii (3.3%) and E. durans (3.3%). A totalof 83.3% of the isolates were resistant to penicillin, whereas 15.0% were resistant toampicillin, 15.0% to vancomycin, 6.7% to tetracycline and 25.0% to ciprofloxacin.Moreover, isolates exhibited 50.0% and 21.7% resistance to high levels of gentamycin andstreptomycin, respectively. The gene asa1 was detected in allenterococcal isolates, whereas 66.7% of strains harbored three or more virulence factorsand 56.7% were asa1-ccf-gelE-positive. In pathogenicity tests, isolates harboring numerousvirulence factors did not show greater invasiveness than isolates harboring fewervirulence traits against Kunming mice. In conclusion, the number ofvirulence factors does not appear to predict the risk of enterococcal infection. Isolateswere commonly resistant to penicillin and sporadically to ampicillin and vancomycin. Theseresults suggest that the use of gentamycin, streptomycin and ciprofloxacin againstenterococci should be avoided in mastitic cows. Additionally, the results demonstrate thatthe majority of isolates are sensitive to tetracycline.

【 授权许可】

Unknown