ANTIMICROBIAL RESISTANCE OF MICROBIOTA FROM READY-TO-EAT FOOD

Konzumacija gotove hrane vrlo je popularna no potrebno je poznavati potencijalne rizike za potrošače u pogledu mikrobiološke sigurnosti. U radu je bio cilj ispitati broj aerobnih mezofilnih bakterija, enterobakterija, enterokoka, koagulaza negativnih stafilokoka te prisutnost Salmonella spp. i Listeria monocytogenes u pakiranim sendvičima s tržišta (n=10). Izolati enterobakterija podvrgnuti su identifikaciji pomoću API 20E i MALDI-TOF MS, te je testirana njihova osjetljivost na antimikrobne tvari. Procjena otpornosti na ceftazidim, nalidiksičnu kiselinu, kloramfenikol, streptomicin, cefotaksim, ciprofloksacin, levofloksacin, tetraciklin, cefalotin, trimetoprim/sulfmetoksazol, kanamicin i cefoksitin određena je pomoću disk difuzijskog testa. Ukupan broj bakterija kretao se između 5,98 – 7,55 log cfu/g, enterobakterija od 0 – 1,9 log cfu/g, enterokoka od 1.3 – 3.52 log cfu/g, stafilokoka od 2 – 4,77 log cfu/g, a patogene bakterije nisu dokazane. Svi izolati bili su otporni na najmanje dvije antimikrobne tvari. Izolati Citrobacter freundii otporni su na cefalotin, tetraciklin, cefoksitin, trimetoprim-sulfametoksazol i kanamicin, Serratia liquefaciens na cefalotin, kanamicin i ceftazidim, a Enterobacter cloacae na cefalotin, kanamicin i trimetoprim/ sulfmetoksazol. Dobiveni rezultati ukazju na kontaminaciju pakiranih sendviča enterobakterijama koje pokazuju otpornost na antimikrobne tvari.Consumption of ready-to-eat foods is very popular, but it is necessary to know the potential risks to consumers in terms of microbiological safety. The aim of this study was to investigate the number of aerobic mesophilic bacteria, enterobacteria, enterococci, coagulase-negative staphylococci and the presence of Salmonella spp. and Listeria monocytogenes in packaged sandwiches from the market (n = 10). Enterobacteriaceae were identified using API 20E and MALDI-TOF MS and their susceptibility to antimicrobial agents was tested. Evaluation of resistance to ceftazidime, nalidixic acid, chloramphenicol, streptomycin, cefotaxime, ciprofloxacin, levofloxacin, tetracycline, cephalothin, trimethoprim / sulfethoxazole, kanamycin and cefoxitin was determined by disk diffusion method. Total bacteria ranged from 5.98 - 7.55 log cfu / g, enterobacteria from 0 - 1.9 log cfu / g, enterococci from 1.3 - 3.52 log cfu / g, staphylococci from 2 - 4.77 log cfu / g, and pathogenic bacteria were not present. All isolates were resistant to at least two antimicrobial agents. Citrobacter freundii isolates were resistant to cephalothin, tetracycline, cefoxitin, trimethoprim-sulfamethoxazole and kanamycin, Serratia liquefaciens to cephalothin, kanamycin and ceftazidime and Enterobacter cloacae to cephalothin, kanamycin and trimethoprim-sulfamethoxazole. The results obtained indicate the contamination of packaged sandwiches with Enterobacteriaceae showing resistance to antimicrobial agents