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

Abstract

<b>Background</b>: 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 <i>Salmonella</i> species and <i>Listeria monocytogenes</i> (<i>LMO</i>), which pose an escalating risk to global public health. <b>Materials and Methods:</b> 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 <i>LMO</i> and the <i>Salmonella</i> species using standard culture-based and molecular methods. The confirmed isolates were subjected to antibiotic susceptibility testing. <b>Results:</b> This study demonstrated the occurrence of multidrug-resistant <i>LMO</i> (62%) and <i>Salmonella</i> species (spp.) (58%) in the red meat specimen. There were high resistance rates in both <i>LMO</i> and <i>Salmonella</i> isolates, with <i>LMO</i> exhibiting resistance to penicillin (89%), colistin (81%), nitrofurantoin (78%), and erythromycin (29%), while <i>Salmonella</i> showed resistance to trimethoprim (96.87%), tetracycline, and colistin (90.62%). Antibiotic resistance genes were also detected including <i>BlaTem</i>, erm, <i>Sul1</i>, <i>Sul2</i> and <i>mcr</i> 1-6. Notably, <i>Salmonella</i> did not harbor any <i>mcr</i> genes that were screened in this study, whereas <i>Listeria</i> isolates harbored the <i>mcr</i> 2 (10%), 3 (7%), 4 (10%), and 6 (3%), with <i>mcr</i> 5 being the most prevalent with 57%. <b>Conclusions:</b> 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.