Antibiotic resistance and prevalence of Enterococcus spp. and Escherichia coli isolated from bryndza cheese

Abstract

The study aimed at determining the prevalence antibiotic resistance of species – identified enterococci and Escherichia (E.) coli isolated from typical fresh Slovak cheese, bryndza. Antibiotic resistance of enterococci was determined by disk diffusion method. Of isolated enterococci, 240 were obtained from bryndza cheese. The first two decimal dilutions from 24 bryndza cheese samples purchased at supermarkets in Košice (0.1 mL) were spread on the surface of Slanetz and Bartley agar and incubated for 48±2 h at 37±1ºC. Species identification of enterococci and E. coli was detected by means of matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry (MALDI-TOF MS) based on bacterial protein profiling. The following species of enterococci were identified by MALDI-TOF MS: Enterococcus (Ent.) faecalis (22 strains), Ent. faecium (18 strains), Ent. sacharolyticus (6 strains), Ent. gilvus (4 strains), Ent. durans (9 strains), and Ent. casseliflavus (6 strains). All of the 45 E. coli strains and 74 strains of enterococci identified by MALDI-TOF MS were determined for occurrence of blaTEM, blaSHV and blaCTX-M genes. The results of our study suggest that the highest resistance of enterococci was on tetracycline (29.73%) and any resistance was recorded on vancomycin (0%). The highest multidrug-resistance was recorded on two antibiotics (32.43%). Neither one isolate of enterococci was resistant to all 6 antibiotics used in the experiment. In total, 19 (42.22%) E. coli were found to be producers of extended-spectrum β-lactamase.

Keywords

• Bryndza cheese
• Enterococcus
• Extended-spectrum beta-lactamases Escherichia coli
• Antibiotic resistance
• MALDI-TOF MS