Coagulase Negative Staphylococci as an emerging cause of bovine subclinical mastitis: prevalence, antimicrobial resistance and biofilm formation

Research Abstract

Coagulase negative Staphylococci (CNS) are the most prevalent cause of bovine subclinical mastitis. The current study was designed to study their occurrence, antibiogram and their ability to form biofilms. A total of 95 CNS isolates were recovered from 400 lactating cows. S. xylosus (36.8%), S. chromogenes (12.6%), S. epidermidis 10.5(%), S. saprophyticus (8.4%), S. haemolyticus (7.4%) were the most prevalent. Disc diffusion method against 14 antimicrobial discs was used to detect their antibiogram. Complete sensitivity to Imipenem was recorded while high sensitivities were recorded against enrofloxacin (96.8%), chlramphenicol (85.3%), vancomycin (84.2%), amoxycillin-clavulinic acid (82.1%) and sulphametoxazole-trimethoprim (80%). On the other hand, high resistances were observed against ampicillin (95.8%) and cefoxitin (77.9%). Cultivation on Congo red agar (CRA) was carried out to detect biofilm formation. About 47.4% of isolates were positive and S. epidermidis was the most biofilm positive (70%). Haemolysis on sheep blood agar showed that 25.3% of isolates were β-haemolytic while 71.6% were γ- haemolytic and 3.2% were α- haemolytic.

Research Keywords

Coagulase Negative Staphylococci, Bovine Subclinical Mastitis, Resistance, Biofilm