Novel macrolide-lincosamide-streptogramin B resistance gene erm(56) in Trueperella pyogenes
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Suppurative infections caused by Trueperella pyogenes, a commensal and opportunistic Gram-positive pathogen of animals, are occasionally treated using macrolides and lincosamides posing the risk of antimicrobial resistance selection. Acquired resistances to macrolide, lincosamide and streptogramin B (MLSB) antibiotics in T. pyogenes have been so far associated with erythromycin ribosome methylase genes, erm(B) or erm(X), located within mobile genetic elements.
T. pyogenes strain 09KM1269, isolated from a dog abscess, exhibited constitutive resistance to erythromycin and clindamycin. Whole genome sequence analysis identified a novel gene, erm(56), that coded for a 23S rRNA methylase and showed the closest relatedness to Erm(X) with only 54% nucleotide and 58% amino acid identity.
Functionality of the new gene was demonstrated by cloning erm(56) and its promoter sequences into pJRD215. The resulting erm(56)-containing plasmid pJEM1269 was subsequently electrotransformed into susceptible strains of E. coli AG100A and T. pyogenes 13OD0707. When erm(56) was expressed from pJEM1269 in T. pyogenes 13OD0707, the MIC increased by more than 256-fold for erythromycin and clindamycin and by 16-fold for pristinamycin IA. Increased MICs of erythromycin (64-fold) and clindamycin (8-fold) were also measured for E. coli AG100A containing pJEM1269.
The erm(56) gene was integrated into the chromosome between two IS6100, situated next to a class 1 integron containing the sulfonamide resistance gene sul1. The erm(56) gene associated with IS6100 was also detected in strains from livestock in China, namely in another T. pyogenes and a Rothia nasimurium. Although a circular conformation containing one copy of IS6100 was detected by PCR, the erm(56) gene could not be transferred by either filter mating or electroporation of genomic DNA into MLSB-susceptible and plasmid-free T. pyogenes strains.
The detection of erm(56) in unrelated bacteria from different animal sources and geographical origins suggests that it has been independently acquired and likely selected by the use of antibiotics.
T. pyogenes strain 09KM1269, isolated from a dog abscess, exhibited constitutive resistance to erythromycin and clindamycin. Whole genome sequence analysis identified a novel gene, erm(56), that coded for a 23S rRNA methylase and showed the closest relatedness to Erm(X) with only 54% nucleotide and 58% amino acid identity.
Functionality of the new gene was demonstrated by cloning erm(56) and its promoter sequences into pJRD215. The resulting erm(56)-containing plasmid pJEM1269 was subsequently electrotransformed into susceptible strains of E. coli AG100A and T. pyogenes 13OD0707. When erm(56) was expressed from pJEM1269 in T. pyogenes 13OD0707, the MIC increased by more than 256-fold for erythromycin and clindamycin and by 16-fold for pristinamycin IA. Increased MICs of erythromycin (64-fold) and clindamycin (8-fold) were also measured for E. coli AG100A containing pJEM1269.
The erm(56) gene was integrated into the chromosome between two IS6100, situated next to a class 1 integron containing the sulfonamide resistance gene sul1. The erm(56) gene associated with IS6100 was also detected in strains from livestock in China, namely in another T. pyogenes and a Rothia nasimurium. Although a circular conformation containing one copy of IS6100 was detected by PCR, the erm(56) gene could not be transferred by either filter mating or electroporation of genomic DNA into MLSB-susceptible and plasmid-free T. pyogenes strains.
The detection of erm(56) in unrelated bacteria from different animal sources and geographical origins suggests that it has been independently acquired and likely selected by the use of antibiotics.
Date of Publication
2023-08
Publication Type
Conference Item
Language(s)
en
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open.access