PHENOTYPIC AND GENOTYPIC DETECTION OF METHICILLIN- RESISTANT STAPHYLOCOCCUS AUREUS (MRSA) IN BROILER CHICKENS

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) has been increasingly reported as emerging problem in veterinary medicine, particularly in small animals and poultry. In Egypt, there is limited information on MRSA carriage in poultry. So the aim of this study was to investigate the prevalence of methicillin resistant staphylococci specifically MRSA in commercial broilers using both phenotypic and genotypic methods. A total of 87 (72.5%) staphylococcal strains were isolated from 120 broiler chicken samples. Out of 87 isolates, 10 (11.5%) were isolated from healthy chickens while the rest 77 (88.5%) were recovered from diseased and dead chickens. Identification of these isolates was performed using combined phenotypic and genotypic methods. Phenotypic identification classified the Staphylococcal isolates into coagulase positive (CPS) and coagulase negative Staphylococci (CNS). Out of 87 staphylococcal strains 37(42 .5%) were coagulase positive Staphylococci (CPS) while 50 (57.5%) were coagulase negative Staphylococci (CNS). Studying the antibiotic Susceptibility profile of 37(CPS) staphylococcal strains against 12 antimicrobial agents revealed that the highest rate of resistant of staphylococcal species was observed to Ampicillin; Methicillin; Gentamicin and Trimethoprim-sulfamethoxazole (100%) while the highest rate of sensitivity was 59.5, 40.5, 29.7 and 21.6 % for Vancomycin; Doxycycline; Streptomycin and Ciprofloxacin, respectively. Genotypic identification of twenty representative coagulase positive Staphylococcus isolates was performed using multiplex PCR assay. All the twenty isolates were found to be Staphylococci by successful amplification of the 228 bp PCR product of the Staphylococcal specific 16S rRNA gene. Simultaneously, 12 out of them were confirmed to be S. aureus by successful amplification of 279 bp PCR product of the S. aureus specific thermonuclease gene while the rest of isolates were identified to be staphylococci other than S. aureus. All the confirmed S. aureus isolates in addition to 5 non S. aureus strains were confirmed to be methicillin resistant through successful amplification of 147 bp specific products. In Conclusion, this study shows high incidence of methicillin resistant among staphylococci and specifically MRSA in broiler chickens including both healthy and diseased ,dead birds in Assiut Governorate, Egypt.