ANTIBIOTIC RESISTANCE OF LACTOBACILLI STRAINS ISOLATED FROM MILK AND MILK PRODUCTS FROM MIDDLE SLOVAKIA

Abstract

The aim of this study was to determine the antibiotic susceptibility of lactobacilli strains isolated from milk and milk products from middle Slovakia. The 42 samples of milk and milk products from sheep farming from middle Slovakia were collected. MRS agar for this cultivation of lactobacilli was used. It was done at 37 °C during 36-48 hours in CO2 box with 10 % CO2. Identification of lactobacilli strains by Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry with Biotyper software – MALDI TOF MS Biotyper was done. Four anitibiotics M.I.C. evaluators strips for antibiotic susceptibility testing were used. These antibiotics were used in this experiment: erythromycin (E 256 – 0.015 µg/ml), ampicillin (AMP 256 – 0.015 µg/ml), gentamycin (CN 256 – 0.015 µg/ml) and tetracycline (TE 256 – 0.015 µg/ml). We isolated 42 lactobacilli strains and identified them as Lactobacillus plantarum and Lactobacillus spp. We isolated 7 strains of Lactobacillus plantarum and 35 isolates were Lactobacillus spp. From the seven isolates of Lactobacillus plantarum 3 isolates were resistant to ampicillin (MIC 16 µg/ml in 2 isolates and MIC 12 µg/ml in one isolate) and one resistant to tetracycline (MIC 16 µg/ml). From 35 isolates of Lactobacillus spp. 9 isolates were resistant to erytromycin (MIC 32 µg/ml), 10 isolates resistant to ampicillin (MIC 16 µg/ml in 4 isolates, MIC 12 µg/ml in 5 isolates and MIC 4 µg/ml in one isolate), 5 isolates resistant to tetracycline (MIC 16 µg/ml). Resistance to gentamycin was not detected. Lactobacilli isolated from milk and milk products were resistant to erytromycin (resistance was 21.42 %), ampicillin (resistance was 30.95 %) and tetracycline (resistance was 14.28 %) and were sensitive in 100 % to gentamycin.