Appraisal of Multidrug-Resistant Listeria monocytogenes and Salmonella spp. Recovered from Commercial Meat Samples in the Eastern Cape, South Africa: Implications for Public Health Safety

Background: Multidrug-resistant bacteria have quadrupled globally, impacting effective treatment of infectious diseases. A growing concern is that many Gram-negative and Gram-positive bacteria harbor genes conferring resistance to various antibiotics including colistin. The alarming emergence of colistin resistance is exacerbated by the growing threat of MDR Salmonella species and Listeria monocytogenes (LMO), which pose an escalating risk to global public health. Materials and Methods: In the present study, red meat samples were collected from randomly selected key retail markets in the Eastern Cape province, South Africa, and were evaluated for the incidence of LMO and the Salmonella species using standard culture-based and molecular methods. The confirmed isolates were subjected to antibiotic susceptibility testing. Results: This study demonstrated the occurrence of multidrug-resistant LMO (62%) and Salmonella species (spp.) (58%) in the red meat specimen. There were high resistance rates in both LMO and Salmonella isolates, with LMO exhibiting resistance to penicillin (89%), colistin (81%), nitrofurantoin (78%), and erythromycin (29%), while Salmonella showed resistance to trimethoprim (96.87%), tetracycline, and colistin (90.62%). Antibiotic resistance genes were also detected including BlaTem, erm, Sul1, Sul2 and mcr 1–6. Notably, Salmonella did not harbor any mcr genes that were screened in this study, whereas Listeria isolates harbored the mcr 2 (10%), 3 (7%), 4 (10%), and 6 (3%), with mcr 5 being the most prevalent with 57%. Conclusions: These findings highlight a threat to food security and public health, emphasizing the need for sturdier food handling procedures to ensure safety, enhanced antimicrobial stewardship, and alternative therapeutic strategies to combat antibiotic-resistant pathogens.