Prevalence of Shigella spp and Methicillin-Resistant Staphylococcus aureus in Select Commercially Processed Meat Products

Aim: The aim of this study was to determine the prevalence of Shigella spp and methicillin resistant Staphylococcus aureus in some selected commercially processed ready-to-eat snail (Archachatina marginata) and edible worm (Rhynchophorus phoenicis).

Study Design: Cross-sectional analysis.

Place and Duration of Study: Samples were obtained from vendors along the Benin-Sapele express road, South-South Nigeria, over a two months period (November to December, 2019).

Methodology: The enumeration of total heterotrophic counts, total Shigella counts and total Staphylococcus aureus counts were done using nutrient agar, Salmonella Shigella agar and mannitol salt agar respectively. All isolates were further identified by their cultural, morphological and biochemical characteristics. Methicillin resistant Staphylococcus aureus were identified using methicillin-oxacillin agar, while the antibiogramic profile of selected isolates and their multidrug resistant profile were done according to the CSLI guideline.

Results: The mean heterotrophic bacterial counts (THCs) obtained in Rhynchophorus phoenicis ranged from 0.00 × 10³ ± 0.00 cfu/g to 500.00 × 10³ ± 0.00 cfu/g, while the mean THCs obtained in Archachatina marginata ranged from 13.3 × 10³ ± 1.15 cfu/g to 500 × 10³ ± 0.00 cfu/g. The total Staphylococcus aureus obtained in Rhynchophorus phoenicis was between 0.00 × 10³ ± 0.00 cfu/g to 294 × 10³ ± 4.7 cfu/g and the Shigella bacteria counts from 0.00 × 10³ ± 0.00 cfu/g to 258 × 10³ ± 14.64 cfu/g. The antibiogram of Staphylococcus aureus isolated from both Rhynchophorus phoenicis and Archachatina marginata, found the majority of isolates (96.67%) to be resistant to ceftazidime and cefuroxime, while 83.33% of the isolates were sensitive to ofloxacin. All Staphylococcus isolates were resistant to ceftriaxone, cloxacillin and amoxycillin clavulanate. The multidrug resistant index recorded was between 37.5 and 100. All Staphylococcus (9) isolates tested for methicillin resistance was observed to be positive.

Conclusion: This study demonstrated that RTE vended meat products sold in along Benin City By-pass, contains Shigella and methicillin resistant Staphylococcus species, which are potential foodborne pathogens and efforts should be made at eliminating them from these vended meat products.