Antibiogram Assay and Pathogenesis of Staphylococcus aureus in Baby Chicks

Abstract

Intensive usage of antibiotics in the poultry sector has become a major area of concern with the consequent emergence of antibiotic-resistant bacteria (ARB) and accordingly their access into the food chain, thus threatening the human health. In the current study, A total of 250 specimens from different local hatcheries of Luxor province (southern Egypt) have been examined for the incidence of Staphylococcus aureus using standard microbiological methods and biochemical tests. The overall prevalence was 27.60% (n = 69/250). Only 30 isolates have been screened for in vitro drug sensitivity bioassay against 18 antimicrobial discs. Our findings revealed that all isolates showed high resistance against в-lactams, including oxacillin (83.33%, n= 25/30), ampicillin (80.00%, n= 24/30), penicillin (73.33%, n= 22/30), and amoxicillin (60.00%, n= 18/30). On the other hand, the highest susceptibility was shown for vancomycin (93.33%, n= 28/30), trimethoprim sulpha methoxazole (80.00%, n= 24/30), and chloramphenicol (70.00%, n = 21/30). Results from a pathogenicity study conducted on 300 one-day-old chicks (SPF) manifested the highest mortality rate of 34.00% in one infected group, and most deaths were in the first three days of all infected groups. Based on the current study, constant monitoring of antibiotic susceptibility phenotypes is deemed prudent and necessary for evaluating the utility of certain antibiotics for treating S. aureus infections. Additionally, any alteration of resistance over the years should be identified, and all centers in charge must determine their own resistance profiles, as reducing the rate of antibiotic resistance will contribute to reducing the cost of treatment. Such measures can lead to improvement of the poultry industry, which represents a vital source of economy in Egypt.