Antimicrobial Resistance of <i>Lactobacillus johnsonii</i> and <i>Lactobacillus zeae</i> in Raw Milk

• Main Authors: Jana Výrostková, Ivana Regecová, Mariana Kováčová, Slavomír Marcinčák, Eva Dudriková, Jana Maľová
• Format: Article
• Language: English
• Published: MDPI AG 2020-12-01
• Series: Processes
• Subjects: antimicrobial resistance; <i>Lactobacillus johnsonii</i>; <i>Lactobacillus zeae</i>; MALDI-TOF-MS; milk; PCR
• Online Access: https://www.mdpi.com/2227-9717/8/12/1627

<i>Lactobacillus johnsonii</i> and <i>Lactobacillus zeae</i> are among the lactobacilli with probiotic properties, which occur in sour milk products, cheeses, and to a lesser extent in raw milk. Recently, resistant strains have been detected in various species of lactobacilli. The aim of the study was to determine the incidence of resistant <i>Lactobacillus johnsonii</i> and <i>Lactobacillus zeae</i> strains in various types of raw milk. A total of 245 isolates were identified by matrix-assisted laser desorption/ionization mass spectrometry and polymerase chain reaction methods as <i>Lactobacillus</i> sp., of which 23 isolates of <i>Lactobacillus johnsonii</i> and 18 isolates of <i>Lactobacillus zeae</i> were confirmed. Determination of susceptibility to selected antibiotics was performed using the E-test and broth dilution method, where 7.3% of lactobacilli strains were evaluated as ampicillin-resistant, 14.7% of isolates as erythromycin-resistant, and 4.9% of isolates as clindamycin-resistant. The genus <i>Lactobacillus johnsonii</i> had the highest resistance to erythromycin (34.8%), similar to <i>Lactobacillus zeae</i> (33.3%). Of the 41 isolates, the presence of the gene was confirmed in five <i>Lactobacillus johnsonii</i> strains and in two strains of <i>Lactobacillus zeae</i>. The presence of resistant strains of <i>Lactobacillus johnsonii</i> and <i>Lactobacillus zeae</i> is a potential risk in terms of spreading antimicrobial resistance through the food chain.