DETECTION OF INTRACELLULAR ADHESION GENE (icaA and icaD)AND BIOFILM FORMATION STAPHYLOCOCCUS AUREUS ISOLATES FROM MASTITIS MILK OF SHEEP AND GOAT

Abstract

In the present study, a total of 150 mastitis milk samples were collected from sheep andgoat (75 for each one) and were analyzed for the presence of S.aureus.. The obtainedresults indicate that this bacterium observed in 20% of these samples (21.33% from sheepand 18.66% from goat) .The study of antibiotic susceptibility test to 9 different antibioticsshowed that S. aureus was 100% resistant to penicillin and 100% sensitive tovancomycin, gentamycin , clarithromycin and chloramphenicol . whereas for cefoxitin(alternative to methicillin) resistance was 47%.There were a variable sensitivitypercentage for the rest of antibiotics: Tetracycline (70%), Ciprofloxacin (80%) ,Clindamycin (83%). The biofilm-forming ability of S. aureus was evaluated viamicrotiter plates and the result revealed that, all the studied isolates were either moderatebiofilm producer or weak biofilm producer while the non-biofilm producer and strongbiofilm producer were not detected among the tested isolate.The relationship betweenbiofilm formation and resistance to methicillin showed there as no significant differences(P>0.05) in the percentage of weak and moderate biofilm producers between MRSA andMSSA isolates. PCR analysis was applied to DNA extracted from S.aureus isolates frommilk samples .The results of PCR assay revealed that all S.aureus isolates gave positiveresults for both icaA and icaD genes (100%) with Product size 151 and 211 bp,respectively.Results of this study indicate that biofilm producing S.aureus have a major role player onthe occurrence of mastitis .In addition, there was high prevalence of MRSA isolates(47%) in mastitic milk at the study area