Antimicrobial resistance profile of Staphylococcus spp. and Listeria spp. isolated from refrigerators of retailers and schools in the Tolon District, Ghana

Abstract

Refrigeration is one of the common and safest food methods aided by the refrigerator which works by distorting the activities/growth of microorganisms. Nevertheless, the refrigerator could be a transmission source of non-pathogenic and pathogenic bacterial strains involved in food spoilage and foodborne infections. The study seeks to assess the knowledge of students and retailers on microbial contamination of refrigerators. Also, the study would determine the occurrence and antimicrobial resistance profile of Staphylococcus spp. and Listeria spp. isolates. The swab-rinse method was employed for sampling refrigerators used by students (n=86) and retailers (n=38) with a total of 248 samples (Interior surfaces n=124, Exterior surfaces n=124). The swab samples were directly streaked on Mannitol Salt Agar and Oxford Listeria Agar Base for the isolation of Staphylococcus spp. and Listeria spp., respectively. Antimicrobial-resistant profile was determined using the Kirby-Bauer disc diffusion method against vancomycin (30 µg), ampicillin (10 µg), and penicillin-G (10 µg). Of the 110 isolates identified, Staphylococcus spp. were (95) with a prevalence of (86.36%) and Listeria spp. were (15) with a prevalence of (13.64%). Antibiotic resistance was most common to penicillin-G (67.27%) followed by ampicillin (60%), and vancomycin (22.73%). This study confirms the presence of cold-tolerant bacteria in refrigerators. Thus, making refrigerators used by students and retailers a potential source of bacterial transmission and/or contamination.