Isolation, DNase-cross-Coagulase test and antimicrobial resistance test on <i>Staphylococcus</i> along beef abattoir line in Addis Ababa Ethiopia

Abstract

Staphylococci are responsible for foodborne infection and intoxication with the spread of antibiotic resistance. The aims of the study were to investigate beef abattoir line contamination with Staphylococcal, to evaluate DNase test for alternative of the tube coagulase test, and to assess isolates drug resistance in Ethiopia. A total of 169 samples from slaughter environment, raw beef at inspection and at public supply along Addis Ababa Abattoir Enterprise line were examined for Staphylococci. The isolates were tested against DNase, tube plasma coagulase, and eight medicinal drugs. A total proportion of 35.5% (60/169) isolates with 13.6% S. aureus and 21.9% coagulase negative Staphylococcus (CNS) were observed. All sampling locations were found positive for Staphylococcus environmental samples ranged from 18.2% - 46.2% with no difference (p > 0.05) among locations. In raw beef, it was 23.5% at abattoir and 52.9% at butchers. Three (1.9%), 13 (7.7%) and 23 (13.6%) of locations were positive for S. aureus only, CNS only and both as a mixed, respectively. Of all 60 Staphylococci isolates, the DNase test and coagulase tests were in agreement for 56 isolates (21 for positive, 35 for negative) showing DNase test was strong agreement with the gold standard test (coagulase tests), kappa=0.86)). S. aureus was 38.3% but CNS was 61.7%. Resistant isolates were observed for trimethoprim (35.0%), polymyxin-B (33.7%), oxytetracycline (31.7%), trimethoprim-sulfamethoxazole (20.0%), chloramphenicol (8.3%), oxacillin (6.7%), and gentamycin (5.0%) but not for tetracycline. Thirty-one (51.7%) isolates were resistant for at least one drug with multiple drugs resistance (MDR) of three to six in 17 isolates. Contamination of all sampling locations with Staphylococcus including with resistant isolate to medically used drugs warrants the application of good hygienic practices along the abattoir line. Due to availability and cost effectiveness, DNase can be used as alternative to the gold standard, coagulase test, for diagnosis of Staphylococcus.

Keywords: Abattoir line; beef; drug resistance; foodborne intoxication; Staphylococci