Coagulase Negative Staphylococci Causing Subclinical Mastitis in Sheep: Prevalence, Phenotypic and Genotypic Characterization

Journal of Veterinary Medical Research

article

Ahmed Hussein Abed¹  Niven Atef Hamed²  Sabreen Ali Abd El Halim² 

[1] Bacteriology,Mycology and Immunology Department, Faculty of Veterinary Medicine, Beni-Suef University;Animal Health Research Institute

关键词: Biofilm;    β-lactams resistance;    blaZ;    icaD and mecA;    Coagulase Negative Staphylococci;    Sheep;    Subclinical Mastitis;   

DOI  :  10.21608/jvmr.2022.145720.1062

学科分类：社会科学、人文和艺术（综合）

来源: Beni-Suef University

【 摘 要 】

Subclinical mastitis (SCM) is one of the most prevalent diseases affecting dairyanimals and hindering the development of animal production sector worldwide.Staphylococci are the most significant causative bacterial pathogens in both clinicaland subclinical cases. The present study aimed to investigate the prevalence of SCMamong sheep detecting the prevalence of coagulase negative staphylococci (CNS) andstudying some of their phenotypic and genotypic characters. A total of 145 individualhalf milk samples (HMSs) were collected aseptically from 75 apparently healthy ewesand examined. The prevalence of SCM based on California Mastitis Test (CMT) was29.3 and 21.4% at sheep and udder HMSs levels, respectively. The prevalence of CNSin subclinically mastitic sheep was investigated in 31 (25.8%) HMSs. Identification ofCNS isolates revealed that, S. epidermidis was the most prevalent (37.5%) followedby S. xylosus (25%) and each of S. simulans, S. chromogenes and S. haemolyticus(12.5%). The results of in-vitro antimicrobial susceptibility of CNS isolates against 12antimicrobial agents showed high resistance against ampicillin, amoxicillin-clavulanicacid, cefoxitin and cefotaxime. Meanwhile, high susceptibilities were recordedagainst ciprofloxacin, levofloxacin, florophenicol, vancomycin, doxycycline,clindamycin, gentamicin and sulfamethoxazole-trimethoprim. The haemolytic activityand biofilm formation on CRA medium were investigated in all isolates. Thehaemolytic activity was detected in 75% of isolates meanwhile 62.5% of isolates werebiofilm formers. The results of genotypic detection of mecA and blaZ resistance genesand icaD biofilm coding gene using PCR showed that they were detected in 80, 60 and60% of the tested isolates, respectively. It was concluded that CNS isolates were themost prevalent causes of ovine SCM and the existence of high percentages ofantimicrobials resistance as well as resistance and virulence genes represent riskfactors and public health hazards and possible danger of lateral transfer of resistancegenes to other microorganisms in both animals and humans.

【 授权许可】

CC BY