Prevalence and antimicrobial resistance of Listeria spp. in homemade white cheese

One hundred and forty-two homemade white cheese samples from various public bazaars were collected and tested for the occurrence of Listeria species. The overall incidence of Listeria spp. in cheese samples was 33.1%. Listeria monocytogenes was isolated from 13 (9.2%) out of 142 studied samples. Other species isolated were Listeria innocua (9.2%), Listeria seeligeri (5.6%), Listeria grayi (4.9%), Listeria ivanovii (2.1%), Listeria welshimeri (2.1%). Also, the antimicrobial susceptibility to various antimicrobial agents of 47 Listeria strains isolated from cheese was tested. Listeria spp. were resistant to penicillin (12.8%), chloramphenicol (8.5%), clarithromycin (6.4%), amikacin (4.3%), tetracycline (2.1%) and cefaclor (2.1%), but sensitive or displayed intermediate susceptibility to amoxicillin-clavulanic acid, vancomycin, gentamicin, ciprofloxacin, rifampin and trimethoprim-sulfamethoxazole.