Screening of Kunun-zaki for Methicillin-Resistant Staphylococcus aureus (MRSA), Vancomycin-Resistant Staphylococcus aureus (VRSA) and Extended-Spectrum Beta-Lactamase (ESBL) Producing Salmonella spp.

Abstract

Kunun-zaki is an indigenous, fermented, non-alcoholic cereal-based beverage produced and consumed primarily in Northern Nigeria. Due to its high nutritional and moisture content, it provides an ideal environment for the growth of foodborne pathogens. This study determined the presence of Methicillin resistant Staphylococcus aureus (MRSA), vancomycin resistant Staphylococcus aureus (VRSA) and Extended spectrum beta lactamase (ESBL) producing Salmonella spp in Kunun-zaki sold in Umuahia metropolis, Nigeria. Out of the 40 Kunun-zaki samples examined, Salmonella spp was detected in 19 (47.5%), whereas S. aureus was detected in 22 (55%) of the samples. The total Salmonella count ranged from 1.90×105-9.70×106 (CFU/ml), whereas the total S. aureus count ranged from 3.40×104-7.50×106 (CFU/ml); these microbial counts do not conform to the standard limits of detectable microbes in ready-to-eat food samples as stipulated by the Center for Food Safety. All the isolates were subjected to antibiotic susceptibility testing using the modified Kirby Bauer disc diffusion method. On the one hand, most of the Salmonella spp were resistant to the beta-lactam class of antibiotics used (IMP 58%, MEM 90%, AMP 53%). On the other hand, the Salmonella isolates showed the highest sensitivities to ceftazidime (95%) and ofloxacin (90%). The S. aureus isolates revealed high susceptibility to ofloxacin (96%), and major resistance to oxacillin (41%) and the oxyimino-cephalosporin antibiotics used (CAZ 55%, CTR 41%). MRSA, VRSA and ESBL producing Enterobacteriaceae are amongst the most critical multidrug-resistant bacterial pathogens. In this study, 26% of the Salmonella spp isolates were confirmed to be ESBL producers, whereas 41% of the isolates were MRSA, 23% were VRSA, and 68% were Vancomycin intermediate Staphylococcus aureus (VISA). Hence, the Kunun-zaki could constitute a reservoir for the dissemination of multidrug-resistant foodborne pathogens if not correctly quality controlled.