Isolation and Identification of Staphylococcus aureus from Milk and Milk Products, Associated Factors for Contamination, and Their Antibiogram in Holeta, Central Ethiopia.

Staphylococcus aureus is a pathogenic bacterium-contaminating milk and milk products causing food poisoning primarily due to its enterotoxins. The study aimed at estimating the prevalence of S. aureus in milk and milk products, assessing potential risk factors for contamination, and determining the load and the antimicrobial susceptibility profile of the isolates. A cross-sectional study design was employed to collect a total of 486 samples, comprising 383 raw milk, 47 bulk tank milk, 29 curd milk (Ergo), and 28 Ethiopian cottage cheese (Ayib) samples. Enumeration, isolation, and identification of S. aureus were carried out following standard microbiological techniques. Antibiogram was performed using 12 antimicrobials following the Kirby-Bauer disc diffusion method. Logistic regression analyses were used to assess the association between the occurrence of S. aureus in milk and milk products and potential risk factors. The overall prevalence of S. aureus was 10.69% (52/486) [95% confidence interval (CI):8.09-13.79%]. The prevalence of S. aureus in raw milk, curd milk, bulk tanks at the farm, bulk tanks at milk collection facilities, and cottage cheese was 8.64%, 24.14%, 14.73%, 23.08%, and 14.29%, respectively. The rate of isolation of S. aureus was significantly high in curd milk than in other types of samples (P = 0.010). The study revealed that teat washing (OR: 4.93, 95% CI: 2.06-11.81), use of towel (OR: 12.13, 95% CI: 3.74-39.29), and tick infestations (OR: 4.31, 95% CI: 1.28-14.44) were risk factors associated with the occurrence of S. aureus in milk. About 48.39% of the milk samples assessed had the S. aureus count higher than 105 CFU/ml. The highest rate of resistance was observed to ampicillin (95%), amoxicillin (95%), oxacillin (87.5%), and cefotaxime (80%). All isolates are resistant to at least two classes of antimicrobial drugs, while 65.0% of the isolates were found to be multidrug-resistant. The moderate prevalence, high load, and antimicrobial resistance of S. aureus indicate the higher public health risk due to the widespread consumption of raw milk in the area. Good hygienic practices, regular surveillance of antimicrobial resistance, and prudent use of drugs are suggested.

Listeria Species Occurrence and Associated Risk Factors and Antibiogram of Listeria Monocytogenes in Milk and Milk Products in Ambo, Holeta, and Bako Towns, Oromia Regional State, Ethiopia.

A cross-sectional study was conducted to estimate the prevalence and associated risk factors of Listeria species and assess the antibiogram of Listeria monocytogenes (L. monocytogenes) isolated from milk and milk products from Holeta, Ambo, and Bako towns, Ethiopia. A total of 482 samples (384 milk, 35 cottage cheeses, 30 bulk tank milk, and 33 curdle milk) were collected using a systematic random sampling method and isolation and identification of Listeria species were done using standard microbiological techniques. An antimicrobial susceptibility test for L. monocytogenes was performed using the Kirby-Bauer disk diffusion technique. Descriptive statistics were used to summarize the prevalence of Listeria, while the Chi-square test and logistic regression were used to determine the association between the prevalence of Listeria and the risk factors and the magnitude of association, respectively. The overall isolation rate of Listeria species from milk and milk products was 7.67% (37/482; 95% confidence interval (CI): 5.46, 10.42). The highest prevalence of Listeria species (15.15%; 95% CI: 5.11-31.90) was detected in bulk tank milk and the lowest prevalence of Listeria species (6.67%; 95% CI: 0.82-22.07) and L. monocytogenes (0.00; 95% CI: 0.00-1.15) was found in curdled milk. The other species isolated were Listeria welshimeri 0.62% (3/482; 95% CI: 0.13-1.81), Listeria seeligeri 1.04% (5/482; 95% CI: 0.33-2.40), Listeria ivanovi 1.24%, (6/482; 95% CI: 0.45-2.68), and Listeria grayi 2.49% (12/482; 95% CI: 5.46-10.42). Univariable logistic regression showed that study town, herd size, farm size, number of lactating cows, and management system were the factors significantly associated with the isolation of Listeria species at farm level, while the intensive management system was the independent predictor at cow level in the multivariable model (adjusted odds ratio = 3.38, P=0.046). L. monocytogenes isolates showed the highest resistance against oxacillin (100%), amoxicillin (90.91%), and vancomycine (81.82%). L. monocytogenes showed a very high multidrug resistance (MDR) [81.82%]. In conclusion, the current study showed the widespread type of Listeria species MDR L. monocytogenes isolates in cow raw milk and milk products from Ambo, Holeta, and Bako towns, Oromia Regional State, Ethiopia.

Occurrence and Antibiogram of Escherichia coli O157 : H7 in Raw Beef and Hygienic Practices in Abattoir and Retailer Shops in Ambo Town, Ethiopia.

Foodborne infections are widespread and growing public health problems in the world. Shiga toxin-producing Escherichia coli O157 : H7 is one of the most significant foodborne pathogens. This study was conducted to assess the occurrence and antibiogram of E. coli O157 : H7 from raw beef as well as hygienic and sanitary practices of meat handling in abattoir and retailer shops. Systematic random sampling technique and census methods were used to collect samples from abattoir and retailer shops, respectively. All tryptone soya broth preenriched carcass samples were subcultured onto MacConkey agar. Then, the bacterium confirmed as Escherichia coli using biochemical tests was streaked onto Sorbitol-MacConkey agar and incubated at 37°C for 24 hrs. Escherichia coli O157 : H7 was confirmed by latex agglutination kit. In vitro antimicrobial susceptibility test of Escherichia coli O157 : H7 isolates was done against 13 antimicrobials. Hygiene and sanitation data were collected using a pretested structured questionnaire and observational checklist. Pearson Chi-square and Fisher's exact two-tailed tests were performed and differences were considered significant at P ≤ 0.05. Out of 197 meat samples, 23.4% (95% confidence interval (CI): 17.6-29.9%) and 9.1% (95% CI: 5.5-14.1%) were contaminated with Escherichia coli and Escherichia coli O157 : H7, respectively. There was a significant variation in the occurrence of Escherichia coli O157 : H7 between retailer shops (19.1%) and abattoir (7.2%) (P = 0.03). The study revealed that the municipal abattoir and retailer shops in Ambo town did not adhere to the required sanitation and hygienic standards. All Escherichia coli O157 : H7 isolates were susceptible to norfloxacin, sulfamethoxazole-trimethoprim, chloramphenicol, and ceftazidime. However, all isolates were resistant to amoxicillin. Multidrug resistance was widespread and was found in 66.3% of Escherichia coli O157 : H7 isolates. The occurrence of Escherichia coli O157 : H7 was high. Therefore, fulfilling national and international meat safety requirements, training and monitoring of meat handlers, and rational use of antimicrobials are recommended.

Listeria Species Occurrence and Associated Factors and Antibiogram of Listeria monocytogenes in Beef at Abattoirs, Butchers, and Restaurants in Ambo and Holeta in Ethiopia.

PURPOSE: Listeriosis is one of the globally distributed foodborne diseases with the highest fatality rate. The objectives of this study were to isolate and identify Listeria species, assess factors for contamination of beef, and antibiogram of Listeria monocytogenes in Ambo and Holeta towns, Central Ethiopia. MATERIALS AND METHODS: A total of 450 meat samples were collected from abattoirs (n=150), butchers (n=150), and restaurants (n=150) for isolation and identification of Listeria species. Logistic regression analysis was used to assess the association between the occurrence of Listeria species in meat and potential risk factors. The antimicrobial susceptibility test was done using the Kirby Bauer test. RESULTS: The overall occurrence of Listeria species in Ambo and Holeta towns was 28.4% (128/450; 95% confidence interval [CI]: 24.3-32.9%). The isolation rate of Listeria monocytogenes was 4.4%, Listeria ivanovii 2.2%, Listeria seeligeri 1.8%, Listeria welshimeri 3.8%, Listeria innocua 6.2%, and Listeria grayi 10.2%. The probability of contamination of meat in butchers and restaurants was higher in Holeta than Ambo [OR=3.4; 95%; p=0.001], in dry than wet season [OR=5.2; p=0.009], and where the hygiene of cutting boards was poor (OR=7.7; p=0.008). Of the 20 Listeria monocytogenes isolates, 80%, 70%, 60%, and 55% were resistant to oxacillin, amikacin, and nalidixic acid, chloramphenicol, and tetracycline, respectively. The Listeria monocytogenes isolates were 95%, 90%, and 85% susceptible to amoxicillin, vancomycin, and clindamycin, respectively. About 95% of Listeria monocytogenes isolates were multidrug-resistant. One isolate (5%) had developed resistance to 10 classes of antimicrobial drugs. CONCLUSION: Listeria species are widespread and study towns, season, and hygiene of cutting boards are independent predictors of isolation of Listeria species. Multidrug resistance among Listeria monocytogenes was very high. Therefore, adequate cooking of meat, regular training of beef handlers, prudent use of drugs, and further molecular studies on Listeria species are important.

Prevalence, Risk Factors, and Antibiogram of Nontyphoidal Salmonella from Beef in Ambo and Holeta Towns, Oromia Region, Ethiopia.

BACKGROUND: Salmonella has been recognized as a major cause of food-borne illness associated with the consumption of food of animal origin. The present cross-sectional study was conducted from December 2017 to May 2018 in Ambo and Holeta towns to assess the prevalence, risk factors, and antimicrobial susceptibility patterns of nontyphoidal Salmonella isolates from raw beef samples from abattoirs, butchers, and restaurants in Ambo and Holeta towns, Oromia region, Ethiopia. METHODS: A total of 354 beef samples were collected from abattoirs, butchers, and restaurants. Salmonella isolation and identification were carried out using standard bacteriological methods recommended by the International Organization for Standardization. Antimicrobial susceptibility testing was performed using the disk diffusion method. Besides, a structured questionnaire was used to collect sociodemographic data and potential risk factors for contamination of meat. Chi-square tests and logistic regression were used for data analyses. RESULTS: Of the total 354 meat samples examined, 20 (5.7%, 95% confidence interval (CI): 3.5-8.6) were positive for Salmonella. Two serotypes belonging to S. typhimurium (11 isolates) and I:4,5,12: i:- (9 isolates) were identified. The Salmonella detection rate in abattoirs, butchers, and restaurants was 4.2% (5/118), 8.5% (10/118), and 4.2% (5/118), respectively. The antimicrobial susceptibility test showed that 40%, 30%, and 20% of the Salmonella isolates were resistant to azithromycin, amoxicillin, and ceftriaxone, respectively. The odds of Salmonella isolation when meat handlers are illiterate were 7.8 times higher than those when they are educated to the level of secondary and above (P=0.032). Similarly, the likelihood of Salmonella isolation was 6.3 and 7.6 times higher among workers of butcher and restaurants, respectively, who had no training (P=0.003) and no knowledge (P=0.010) on food safety and hygiene. CONCLUSIONS: The study showed widespread multidrug-resistant Salmonella isolates in the study areas. Therefore, raw meat consumption and indiscriminate use of antimicrobial drugs should be discouraged. Provision of food safety education for meat handlers and further surveillance of antimicrobial-resistant isolates are suggested.