Occurrence and Antimicrobial Susceptibility Patterns of Staphylococcus ‎aureus and Salmonella species in Fresh Milk and Milk Products Sold in Zaria ‎and Environs, Kaduna State, Nigeria

Abstract

Staphylococcal infections and salmonellosis are important food-borne diseases affecting both humans and animals, and the spread of antibiotic resistant bacteria to humans through the consumption of animal food products remains a challenge. To determine the occurrence and antimicrobial susceptibility pattern of Staphylococcus aureus and Salmonella in fresh milk and milk products sold in Zaria and environs, Kaduna State, Nigeria, ninety samples were purchased comprising of 49 pasteurized milk, 20 ghee (Clarified butter) and 21 fresh milk samples in Zaria. The Samples were pre-enriched before plating on a suitable selective media. Biochemical and Sugar fermentation tests were used to detect S. aureus and Salmonella isolates; also, antimicrobial susceptibility test was carried out on positive isolates. The overall prevalence of S. aureus and Salmonella spp. in fresh milk and milk products (pasteurized milk and ghee) were 31.1% (28/90) and 6.7% (6/90), respectively. Higher prevalence of S. aureus was found in fresh milk (38.1%) than in ghee (35%) and pasteurized milk (26.5%). Also, a higher prevalence of Salmonella organism was found in fresh milk (9.5%) than in pasteurized milk (6.1%) and ghee (5%). Positive iso­lates of S. aureus showed the highest percentage of antibiotic resistance to oxacillin (100%), then tetracycline (64%) and vancomycin (57.1%), while positive iso­lates of Salmonella showed oxacillin (100%) and vancomycin (100%), followed by tetracycline (33.3%). Most of the isolates displayed resistance to more than three (3) different classes of antimicrobials, indicating multi-drug resistance. Therefore, there is a need for education and public awareness regarding hygienic processing, handling and storage of fresh milk and milk products; thus, the abuse and indiscriminate use of antibiotics in animals should be discouraged.

Staphylococcus aureus contamination of animal-derived foods in Nigeria: A systematic review, 2002 - 2022

“…Other four studies were conducted in Kaduna and its environs (Umaru et al 2014;Usman et al 2016;Okpo et al 2017;Esonu et al 2021). Usman et al (2016) found an overall prevalence of 3.1% from yogurt and "nono" samples.…”

“…Umaru et al (2014) reported the highest prevalence from milk samples, with 47 (12.4%) S. aureus isolates observed from 372 milk (raw milk, bulk milk, "kindirmo", pasteurized milk, and yogurt) samples. A recent study reported a prevalence of 3.1% with 28 isolates out of 90 samples of pasteurized milk, "ghee", and fresh milk samples in Zaria and its environs (Esonu et al 2021).…”

“…(Obadina et al 2014;Ghali-Mohammed et al 2022) that serve as easy entry points for S. aureus into the food chain. Processing plants, traditional milking, and milk cuddling methods (Esonu et al 2021) were also highly incriminated, albeit some of the processing techniques were shown to reduce contamination of the food, among which are heating/Smoking of meat (Adeyeye et al 2015;Amaeze et al 2016) and fish (Orogu et al 2018) that showed low prevalence linked to the inability of S. aureus to survive under high temperatures.…”

Prevalence and antimicrobial susceptibility profile of Staphylococcus aureus isolated from marketed milk and cheese in Ilorin, Nigeria

“…In this study, an expected Staphylococcus aureus prevalence of 33.1% in milk (Esonu et al, 2021), and an absolute error margin of 5% were used in the calculation of the sample size. Therefore, n = 330.…”

“…This can have positive implications for both public health and the dairy industry in Ilorin. While studies on the contamination of milk and cheese by foodborne pathogens like S. aureus exist globally (Kou et al, 2021;Alembo & Torka, 2023) and elsewhere in Nigeria (Olufemi et al, 2018;Omoshaba et al, 2018;Aliyu et al, 2019;Oludairo et al, 2020;Esonu et al, 2021;Hassan et al, 2021;Aliyu et al, 2022;Ghali-Mohammed et al, 2022), localized data specific to Ilorin, Nigeria, are limited. This study will contribute valuable data that can be used for region-specific interventions and guidelines.…”