Research Article

Characterization of antimicrobial resistant bacterial pathogens recovered from cases of bovine mastitis with special reference to Staphylococcus aureus

Hassan W. H., Hatem M. E., Elnwary H. A., Sediek S. H.
Department of Bacteriology, Mycology and Immunology, Faculty ofVeterinary Medicine, Beni-Suef University, Beni-Suef 62511, Egypt.

Abstract

In the current study, a total of 20 and 78 milk samples were collected from animals showed signs of clinical and subclinical mastitis, for isolation and identification of different causative pathogens in some dairy farms of Beni-Suef Governorate, and for investigation of in vitro sensitivity. The recovered microorganisms were Staphylococcus species (n=79; 80.61%), Enterococcus spp. (n=28; 28.57%), CAMP negative Streptococci, Pseudomonas aeruginosa (n=7; 7.14%), E. coli (n=3; 3.06%) and Proteus vulgaris (n=1; 1.02%). Antibiogram profile for S. aureus showed that the most effective drug was vancomycin and the least was penicillin. Trials were done to detect biofilm production for recovered isolates of S. aureus (n=23) by the use of a phenotypic method (Congo red agar, CRA) and genotypic methods through determination of some biofilm related genes using PCR. All recovered S.aureus isolates were seeded on the CRA media to detect the biofilm forming ability. It has been found that all tested isolates showed a biofilm forming ability either strong (13; 56.52%) or intermediate (10; 43.48%). The detection of some biofilm associated genes (icaA, icaD and bap genes) using polymerase chain reaction revealed that two (10.53%) isolates out of 19 were negative for all tested genes, 16 (84.21%) isolates harbored both icaA and icaD gene, while only one (5.26%) isolate had all tested genes.

Keywords

Mastitis,antimicrobial sensitivity, S. aureus, biofilm