Assessment of antibiotic susceptibility in Lactobacillus isolates from chickens

• Published in: Gut pathogens Vol. 9; no. 1; p. 54
• Main Authors: Dec, Marta, Urban-Chmiel, Renata, Stępień-Pyśniak, Dagmara, Wernicki, Andrzej
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 19.09.2017; BioMed Central; BMC
• Subjects: Amino acids; Aminoglycoside antibiotics; Ampicillin; Animals; Antibiotic susceptibility; Antibiotics; Antimicrobial agents; Bacteria; Birds; Breakpoints; Chickens; Chloramphenicol; Deoxyribonucleic acid; DNA; Drug resistance; Enrofloxacin; Enterococcus faecalis; Enterococcus faecium; Farms; Feeds; Food; Gene expression; Genetic aspects; Gram-negative bacteria; Gram-positive bacteria; Health aspects; Intestine; Lactobacillus; Lincomycin; Lincosamides; Multidrug resistance; Mutation; Plasmids; Poultry; Probiotics; Resistance genes; Ribosomal DNA; Staphylococcus aureus; Tetracyclines; Tiamulin; Poultry; Resistance genes; Antibiotic susceptibility; Lactobacillus
• ISSN: 1757-4749; 1757-4749
• DOI: 10.1186/s13099-017-0203-z

The aim of this study was to determine the susceptibility of 88 isolates derived from chickens to antibiotic substances and to detect drug-resistance genes. The minimal inhibitory concentration of 13 antimicrobial substances was determined by the broth microdilution method, and resistance genes were detected by PCR. We recorded a high prevalence of resistance to tiamulin (90% resistant isolates), tetracyclines (74%) and lincomycin (70%), and a moderately high frequency of resistance to enrofloxacin (48%), macrolides (42%), aminoglycosides (12.5-31%), ampicillin (26%) and chloramphenicol (23%). Multi-drug resistance was observed in 79.5% of isolates. The presence of resistance genes was generally correlated with phenotypic resistance, but some molecular determinants were also recorded in susceptible isolates. Among tetracycline resistance genes, the most frequently identified was (45% isolates), followed by (26%) and (24%). The , and genes, associated with resistance to macrolides and lincosamides, were observed in 39, 12 and 39% of isolates, respectively. Among genes determining resistance to aminoglycoside antibiotics, we identified - (10% of isolates), ' - - ' - (8%), ″ - (6%) and (4.5%). The gene was present in 32 isolates, including 8 of 20 found to be resistant to chloramphenicol. Two genes encoding efflux pumps were identified-the gene was present in all isolates tested, and 10 of 79 lactobacilli determined to be phenotypically resistant to tiamulin contained the gene. We were unable to explain the resistance mechanism of isolates to ampicillin, but showed that it did not involve the production of β-lactamases. Our findings indicate that intestinal lactobacilli should be considered a reservoir of resistance genes and that antibiotics must be used prudently in poultry production. The data derived from this study can be used as a basis for reviewing current microbiological breakpoints for categorization of susceptible and resistant strains within the genus .