Abstract:
Staphylococci are the main cause of food borne intoxication and food borne outbreaks
worldwide due to its ubiquity and ability to persist and grow under various conditions. A crosssectional study was carried out between the periods of May 2014 to March 2015 with the aims 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. Identification of the
staphylococci was undertaken using Gram's staining, catalase, sugar fermentation and coagulase
tests on 400 samples (cottage cheese = 200, yoghurt = 200) collected by simple random sampling
technique. 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). Four species of staphylococci were identified and their prevalence was
confirmed to be 5%, 3.5%, 3.3% and 5.8% for S. aureus, S. intermedius, S. hyicus and coagulase
negative staphylococci respectively. The specific prevalences 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% (coagulase negative staphylococci). The identification results
showed that 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%). A large proportion
of the isolates (87.1%) were resistant to one or more antimicrobials. The staphylococci found in
cottage cheese and yoghurt was could be due to traditional methods of milking, handling,
preparing, storing, selling and hygienic status of the personnel. The high antimicrobial resistance
of the staphylococcal isolate observed might be due to indiscriminate use of the drug at the study
area. Hence, sanitary measures and awareness creations are needed 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 health and quality of these highly popular products.
