16S rRNA gene mutations associated with decreased susceptibility to tetracycline in Mycoplasma bovis.
Mycoplasma bovis isolates with decreased susceptibilities to tetracyclines are increasingly reported worldwide. The acquired molecular mechanisms associated with this phenomenon were investigated in 70 clinical isolates of M. bovis. Sequence analysis of the two 16S rRNA-encoding genes (rrs3 and rrs4 alleles) containing the primary binding pocket for tetracycline (Tet-1 site) was performed on isolates with tetracycline hydrochloride MICs of 0.125 to 16 μg/ml. Mutations at positions A965T, A967T/C (Escherichia coli numbering) of helix 31, U1199C of helix 34, and G1058A/C were identified. Decreased susceptibilities to tetracycline (MICs, ≥2 μg/ml) were associated with mutations present at two (A965 and A967) or three positions (A965, A967, and G1058) of the two rrs alleles. No tet(M), tet(O), or tet(L) determinants were found in the genome of any of the 70 M. bovis isolates. The data presented correlate (P<0.0001) the mutations identified in the Tet-1 site of clinical isolates of M. bovis with decreased susceptibility to tetracycline.
Division of Avian and Aquatic Diseases, Kimron Veterinary Institute, Bet Dagan, Israel Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot, Israel.
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Amram
Division of Avian and Aquatic Diseases, Kimron Veterinary Institute, Bet Dagan, Israel.
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Mikula
Friedrich-Loeffler-Institute, Jena, Germany.
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Schnee
Animal and Plant Health Agency, Addlestone, United Kingdom.
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Ayling
Animal and Plant Health Agency, Addlestone, United Kingdom.
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Nicholas
Animal and Plant Health Agency, Addlestone, United Kingdom.
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Rosales
Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot, Israel.
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Harrus
Division of Avian and Aquatic Diseases, Kimron Veterinary Institute, Bet Dagan, Israel innal@moag.gov.il.
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Lysnyansky
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D009154:Mutation; D045682:Mycoplasma bovis / Q000187:drug effects / Q000235:genetics*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013752:Tetracycline / Q000494:pharmacology*; D013753:Tetracycline Resistance / Q000235:genetics*
D000900:Anti-Bacterial Agents; D012336:RNA, Ribosomal, 16S; D013752:Tetracycline