Pathogenic Potential and Antimicrobial Resistance Profile of Staphylococcus aureus in Milk and Beef from the Northwest and Southwest Regions of Cameroon

Abstract

Staphylococcus aureus is a major foodborne pathogen and commensal of the skin and mucous membranes of animals and humans. Its virulence relies on the production of a variety of toxins resistant to denaturing conditions. Increasing reports of S. aureus food poisoning and contamination of foods of animal origin elsewhere necessitates the investigation of these foods in Cameroon, to implement safety measures. This cross-sectional study evaluated S. aureus contamination in milk and beef in the Northwest and Southwest Regions of Cameroon, where cow milk is usually not pasteurized before consumption, and beef is the main source of protein. The distribution of antibiotic-resistant isolates and those with enterotoxin-producing potential was also investigated to provide data of public health and food safety benefit. S. aureus was isolated from 39 raw milk and 250 beef samples by standard methods. Confirmation of isolates was by PCR to detect the nuc gene. S. aureus was investigated for classical staphylococcal enterotoxin (SE) genes (sea, seb, sec, sed, and see) by PCR. Their susceptibility to 9 antibiotics was tested by the disk diffusion method. The chi-square test was used to compare the contamination of samples, antibiotic resistance, and the distribution of SE genes. S. aureus was isolated from 11.1% of samples. Contamination was higher in milk (48%) than in beef (5.2%) ( P < 0.001 ). The sea was the most frequently (90%) harboured gene. A large proportion of isolates (88%) harboured more than one virulence gene. Isolates were generally resistant to erythromycin (82%), vancomycin (80%), tetracycline (76%), and oxacillin (74%). Multidrug resistance (MDR) was common (92%). Milk and beef samples in study area were contaminated with MDR enterotoxigenic S. aureus strains and may constitute a potential hazard to consumers. Thus, the need for implementation of proper hygienic measures when handling these products and pasteurization of milk cannot be overemphasized.

Properties of coagulase-positive staphylococcal cells that make it difficult to diagnose and treat mastitis in cows

“…They were most often resistant to erythromycin (62%), ampicillin (62%) and oxacillin (46%) [15]. On the other hand, Bissong MAE (2020), analyzing the resistance of staphylococcus aureus, showed 39 isolates S. aureus from 289 microorganisms [16]. In both of these studies, staphylococci were characterized by high resistance to erythomycin (82% -Bissong, 62% -Mphahlele), and in the case of Bissong MAE work, there was high resistance to vancomycin (80%) and tetracycline (76%).…”

Comparative Approach of the Antibiotics Susceptibility of some Bacterial Strains Concurrently Isolated from Raw Milk and Cattle Feed (Water and Fodder) from some Farms in the West Region of Cameroon (Central Africa)

“…Furthermore, the study revealed that 71% and 67% of E. coli were resistant to tetracycline in milk and drinking water respectively, while less resistance (20%) was observed in green fodder. Antibiotic resistance can be transferred to humans via the food chain through consumption of antimicrobial residues or contamination of resistant bacteria in animal products [10].…”

“…Antibiotic susceptibility testing revealed 95% resistance to β-lactamases, 78% to Macrolides, 42% to Glycopeptides, 16% to Quinolones, 5% to Aminosides and Cotrimoxazole and 0% to Chloramphenicol [9]. Another study on the pathogenicity and antimicrobial resistance profile of Staphylococcus aureus in beef and milk in the North West and South West regions of Cameroon revealed that the majority of isolates were resistant to erythromycin (82%), vancomycin (80%), tetracycline (76%) and oxacillin (74%) [10]. The increasing prevalence of antibiotic resistance (AR) is a global concern and the role of raw milk in the spread of AR is unclear [4].…”

Prevalence and Characterization of Methicillin-Resistant Staphylococcus aureus from Meat Retail Shops and Meat Handlers in the Buea Municipality, Cameroon

“…Kesah et al [12] reported 21.3% (21/127) MRSA prevalence; while Njoungang et al [13] documented 13.9% (28/201) from clinical samples in Yaounde. Also, Bissong et al [14] reported 13.2% from clinical samples in Douala and equally documented that 37 (74%) of the 50 S. aureus isolates identified from 289 samples (milk and beef) from the Northwest and Southwest Cameroon were MRSA [15]. All these studies identified MRSA based on phenotypic (oxacillin or cefoxitin screening) methods only.…”