title: Antimicrobial resistance and virulence-related genes of Streptococcus obtained from dairy cows with mastitis in Inner Mongolia, China.
abstract: BACKGROUND
  Mastitis is the most expensive disease in the dairy cattle industry and results in decreased reproductive performance. Streptococcus, especially Streptococcus agalactiae, possesses a variety of virulence factors that contribute to pathogenicity.
  
  
  OBJECTIVE
  Streptococcus isolated from mastitis was tested to assess the prevalence of antimicrobial resistance and distribution of antibiotic resistance- and virulence-related genes.
  
  
  METHODS
  Eighty-one Streptococcus isolates were phenotypically characterized for antimicrobial resistance against 15 antibiotics by determining minimum inhibitory concentrations (MIC) using a micro-dilution method. Resistance- and virulence-related genes were detected by PCR.
  
  
  RESULTS
  High percentage of resistance to β-lactams, along with tetracycline and erythromycin, was found. Resistance to three or more of seven antimicrobial agents was observed at 88.9%, with penicillin-tetracycline-erythromycin-clindamycin as the major profile in Streptococcus isolates. Resistant genes were detected by PCR, the result showed that 86.4, 86.4, 81.5, and 38.3% of isolates were mainly carrying the pbp2b, tetL, tetM, and ermB genes, respectively. Nine virulence genes were investigated. Genes cyl, glnA, cfb, hylB, and scaA were found to be in 50% of isolates, while 3.7, 21, and 4.9% of isolates were positive for bca, lmb, and scpB, genes, respectively. None of the isolates carried the bac gene.
  
  
  CONCLUSIONS
  This study suggests the need for prudent use of antimicrobial agents in veterinary clinical medicine to avoid the increase and dissemination of antimicrobial resistance arising from the use of antimicrobial drugs in animals.
authors: a Department of Veterinary Pharmacology & Toxicology , College of Veterinary Medicine, Inner Mongolia Agricultural University , Hohhot , Inner Mongolia Autonomous Region , PR China .|b Laboratory of Clinical Diagnosis and Treatment Techniques for Animal Disease , Ministry of Agriculture , Hohhot , Inner Mongolia Autonomous Region , China .
authors: Yuexia
authors: Y
authors: Ding
authors: c Inner Mongolia Academy of Agricultural & Animal Husbandry Sciences , Hohhot , Inner Mongolia Autonomous Region , PR China , and.
authors: Junli
authors: J
authors: Zhao
authors: a Department of Veterinary Pharmacology & Toxicology , College of Veterinary Medicine, Inner Mongolia Agricultural University , Hohhot , Inner Mongolia Autonomous Region , PR China .|b Laboratory of Clinical Diagnosis and Treatment Techniques for Animal Disease , Ministry of Agriculture , Hohhot , Inner Mongolia Autonomous Region , China .
authors: Xiuling
authors: X
authors: He
authors: a Department of Veterinary Pharmacology & Toxicology , College of Veterinary Medicine, Inner Mongolia Agricultural University , Hohhot , Inner Mongolia Autonomous Region , PR China .|b Laboratory of Clinical Diagnosis and Treatment Techniques for Animal Disease , Ministry of Agriculture , Hohhot , Inner Mongolia Autonomous Region , China .
authors: Man
authors: M
authors: Li
authors: a Department of Veterinary Pharmacology & Toxicology , College of Veterinary Medicine, Inner Mongolia Agricultural University , Hohhot , Inner Mongolia Autonomous Region , PR China .|b Laboratory of Clinical Diagnosis and Treatment Techniques for Animal Disease , Ministry of Agriculture , Hohhot , Inner Mongolia Autonomous Region , China .
authors: Hong
authors: H
authors: Guan
authors: d College of Basic, Inner Mongolia Medical University , Hohhot , Inner Mongolia Autonomous Region , PR China.
authors: Ziying
authors: Z
authors: Zhang
authors: a Department of Veterinary Pharmacology & Toxicology , College of Veterinary Medicine, Inner Mongolia Agricultural University , Hohhot , Inner Mongolia Autonomous Region , PR China .|b Laboratory of Clinical Diagnosis and Treatment Techniques for Animal Disease , Ministry of Agriculture , Hohhot , Inner Mongolia Autonomous Region , China .
authors: Peifeng
authors: P
authors: Li
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002417:Cattle; D002681:China; D003612:Dairying; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005260:Female; D005838:Genotype; D008414:Mastitis, Bovine / Q000175:diagnosis / Q000188:drug therapy / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D010641:Phenotype; D016133:Polymerase Chain Reaction; D013290:Streptococcal Infections / Q000175:diagnosis / Q000188:drug therapy / Q000382:microbiology*; D013291:Streptococcus / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D037521:Virulence Factors
keywords: Antimicrobial resistance; Streptococcus; mastitis; virulence