Identification and Antimicrobial Resistance Pattern of Staphylococci Isolated From Cottage Cheese (Ayib) and Yoghurt (Ergo) in Selected Districts of Jimma Zone, Ethiopia

Abstract

Background: Staphylococci related illness is among serious public-health problems and the second most expensive diseases to treat in developing country. According to WHO estimation, staphylococcal related food borne disease are the second most common food borne disease next to salmonella. Although staphylococci related illness is affecting the majority of Ethiopian, much is not known about the extents of Staphylococcus species and their antimicrobial resistance pattern in cottage cheese (Ayib) and yoghurt (Ergo). Objectives: To investigate the occurrence of Staphylococcus, determine the prevalence of Staphylococcus and evaluate the antimicrobial resistance pattern of the isolates from cottage cheese (Ayib) and yoghurt (Ergo) collected from selected districts of Jimma Zone, Ethiopia. Methods: Identification of staphylococci was undertaken using Gram's staining, catalase, sugar fermentation and coagulase tests on cottage cheese (n=200) and yoghurt (n=200) samples collected randomly. The data were analyzed using SPSS version 20.0. Results: The overall prevalence of Staphylococcus in this study was found to be 14.3% with a specific prevalence of 22% in cottage cheese and 6.5% in yoghurt. The difference on the prevalence of staphylococci between cottage cheese and yoghurt was found to be statistically significant (P<0.05). The prevalence of Staphylococcus species was confirmed to be 5%, 3.5%, 3.3% and 5.8% for S. aureus, S. intermedius, S. hyicus and coagulase negative staphylococci (CNS) respectively. The specific prevalence in cheese and yoghurt for each species respectively were 7% and 3% (S. aureus), 5.5% and 1.5% (S. intermedius), 4% and 2.5% (S. hyicus), and 9.5% and 2% (CNS). The contamination of cottage cheese with staphylococcus was more likely to occur than yoghurt (OR=4.1, 95%, CI=2.1-7.8). The disc diffusion assay of 70 isolates against five biogram revealed the highest resistance to penicillin G (65.7%) followed by tetracycline (41.4%), streptomycin (37.1%), gentamycin (35.7%) and kanamycin (28.6%). Conclusion: The high prevalence of Staphylococcus and their high antimicrobial resistance pattern in cottage cheese and yoghurt in this study represent a poor keeping quality and indiscriminate use of drugs at the study area. This suggests the need to implement sanitary measures and awareness creations to improve the hygienic conditions of cheese and yoghurt from farm-to-table continuum as well as proper use of antimicrobials in order to guarantee the quality of these highly popular products and to safeguard the health of the consumers.