Multilocus sequence typing and antimicrobial susceptibility of Listeria monocytogenes isolated from foods surveyed in Kosovo

Abstract

In the absence of data on the reporting of L. monocytogenes resistance to antibiotics, we sought to determine which clonal complexes (CCs)/sequence types (STs) circulate in the food chain in Kosovo and to determine their antibiogram profiles to a panel of 18 antibiotics. From a total of 114 isolates, 21 different typical STs were identified by multilocus sequence typing (MLST). Each isolate derived from the food categories was subjected to tests to verify its susceptibility to the selected antibiotics according to the designed Sensititre GPN3F panel. Among the different STs that were identified, CC9-ST9 was more abundant in meat products (38.75%) while CC29-ST29 was more abundant (24.0%) in dairy products. Moreover, these isolates showed marked resistance against levofloxacin (22.8%), gentamicin and rifampicin (17.5%), quinupristin/dalfopristin (14.9%), erythromycin (11.4%), penicillin (7.89%), tetracycline (1.75%), and streptomycin (0.88%). A total of 27 multiple antibiotic resistance (MAR) phenotypes were observed amongst the isolates, which ranged from 3 to 12. The ARI of the food category including meat and meat products (MMP, 0.22) and fish meat products (FMP, 0.26) were >0.2, the permissible Krumperman threshold. The number of strains with MAR values >0.2 was 34, (29.8%). The identification of typical multidrug-resistant STs among L. monocytogenes isolates in Kosovo constitutes a potential threat to food safety and public health, which requires