Staphylococcus aureus Causing Subclinical Mastitis in Goats: Prevalence, Phenotypic and Genotypic Characterization

Journal of Veterinary Medical Research

article

Ahmed Hussein Abed¹  Niven Atef Hamed²  Sabreen Abd El Halim² 

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

关键词: Biofilm;    Goats;    Hemolysis;    S. aureus;    Subclinical Mastitis;   

DOI  :  10.21608/jvmr.2022.145725.1063

学科分类：社会科学、人文和艺术（综合）

来源: Beni-Suef University

【 摘 要 】

The dairy goat industry is rapidly developing worldwide as a result of increasing theawareness about the high quality and nutritional properties of caprine milk. Subclinicalmastitis (SCM) is one of the most important challenges facing goat industry and leadingto great economic losses. S. aureus has been regarded for long time as one of the mostleading cause of mastitis either clinical or subclinical. The present study aimed toinvestigate the prevalence of SCM among goats and to isolate S. aureus as well as studysome of their phenotypic and genotypic characters. A total of 143 individual half milksamples (HMSs) were collected aseptically from 75 apparently healthy goats andexamined. S. aureus were isolated and identified phenotypically using conventionalmethods in addition to using Vitek2 compact system. The selected isolates wereconfirmed by the detection of staphylococcal 16S rRNA gene. The prevalence of SCMbased on California Mastitis Test (CMT) was 41.3 and 34.3% at goats and udder HMSslevels, respectively. The prevalence of S. aureus isolation in subclinically mastitic goatswas investigated in 49 HMSs as 26.5%. The results of in-vitro antimicrobial susceptibilityof S. aureus isolates against 12 antimicrobial agents showed high resistance againstampicillin, amoxicillin-clavulanic, cefoxitin, cefotaxime and vancomycin. Meanwhile, highsusceptibilities were recorded against ciprofloxacin, levofloxacin, florophenicol,doxycycline HCl, clindamycin, gentamicin and sulfamethoxazole-trimethoprim. Thehemolytic activity and biofilm formation on CRA medium were investigated in all isolates.The hemolytic activity was detected in 76.9% of isolates meanwhile 53.8% of isolateswere biofilm formers, respectively. The results of genotypic detection of mecA, blaZ andvanA resistance genes using PCR showed that they were detected in 100, 71.4 and 42.9%of the tested isolates, respectively. Meanwhile, biofilm and α-hemolysin coding genes(icaD and hla) were detected in 71.4 and 42.9% of the tested isolates, respectively. It wasconcluded that S. aureus is one of the most prevalent cause of caprine SCM and theexistence of high percentages of antimicrobials resistance as well as resistance andvirulence genes represent risk factors and public health hazards and possible danger oflateral transfer of resistance genes to other microorganisms in both animals and humans.

【 授权许可】

CC BY