Characterization of In Vivo Acquired Resistance of Mycoplasma hyopneumoniae to Macrolides and Lincosamides

Abstract

Macrolides and related antibiotics are used to control mycoplasma infections in the pig industry worldwide. Some porcine mycoplasmas, however, survive these treatments by acquiring resistance. The mechanism of acquired resistance to macrolides and lincosamides was studied in more detail for Mycoplasma hyopneumoniae by comparing both the phenotype and genotype of a resistant field isolate to five susceptible isolates. The MICs were significantly higher for the resistant strain for all antibiotics tested. The MICs for the 16-membered macrolide tylosin ranged from 8 to 16 microg for the resistant strain and from 0.03 to 0.125 microg/ml for the five susceptible strains. The MICs for the 15-membered macrolides and lincosamides were higher than 64 microg/ml for the resistant strain while only 0.06 to 0.5 microg/ml for the susceptible strains. Mycoplasma hyopneumoniae strains are intrinsically resistant to the 14-membered macrolides due to a G 2057 A transition (E. coli numbering) in their 23S rDNA. Therefore, high MICs were observed for all strains, although the MICs for the resistant strain were clearly increased. An additional, acquired A 2058 G point mutation was found in the 23S rRNA gene of the resistant strain. No differences linked to resistance were found in the ribosomal proteins L4 and L22. The present study showed that 23S rRNA mutations resulting in resistance to macrolides and lincosamides as described in other Mycoplasma spp. also occur under field conditions in M. hyopneumoniae.

<i>In Vitro</i> Susceptibility of <i>Mycoplasma hyopneumoniae</i> Field Isolates and Occurrence of Fluoroquinolone, Macrolides and Lincomycin Resistance

“…The resistance of two strains to macrolides and lincomycin was shown to be attributable to a transition of A to G at 2058 (E. coli coordinates) in the central loop of domain V of the 23S rRNA. It was in agreement to the occurrence in Japan and Belgium [10,17]. Erythromycin is highly active to M. pneumoniae [9] and M. gallisepticum [4], however, M. hyopneumoniae has natural resistance to this drug, as indicated not only by the present data but also by the previous reports [18][19][20]23].…”

“…Excessive medication may cause a decrease of susceptibility of mycoplasmas against antimicrobial agents [11,21,23]. To date, antimicrobial resistance of porcine mycoplasmas has been reported to tetracyclines, macrolides, lincomycin and flumequine, the first generation fluoroquinolone in some countries [1,6,17,21,22]. In Thailand, susceptibility of M. hyopneumoniae to antimicrobial agents was investigated for the isolates collected in 1997-1998, and no resistant isolates were found in that period [14].…”

Mutations of domain V in 23S ribosomal RNA of macrolide-resistant Mycoplasma gallisepticum isolates in Egypt

“…In nucleotide position 2057, a guanine to adenine transition was reported in three erythromycinresistant M. gallisepticum isolates. Actually, those mutations were the most frequently reported in the erythromycin-resistant isolates of M. gallisepticum genetically characterized [17,31] and have been previously reported as hot spots for macrolide resistance in other mycoplasmas [32,33]. Based on our results, transition can be considered the predominant type of mutation in M. gallisepticum.…”

Flow Cytometric Determination of the Effects of Antibacterial Agents on Mycoplasma agalactiae , Mycoplasma putrefaciens , Mycoplasma capricolum subsp. capricolum , and Mycoplasma mycoides subsp. mycoides Large Colony Type

“…It has wide-ranging clinical and experimental applications in investigations of eukaryotic cells and also looks very promising in the case of bacteria (4). On the basis of these considerations, it is appropriate to attempt to apply this methodology to the assessment of the antibiotic susceptibilities of these four mycoplasma species because of their importance in disease and because of their increasing resistance to previously active antibiotics (7,12,18,19).The reference strains of M. mycoides subsp. mycoides LC, M. agalactiae, M. putrefaciens, and M. capricolum subsp.…”

“…It has wide-ranging clinical and experimental applications in investigations of eukaryotic cells and also looks very promising in the case of bacteria (4). On the basis of these considerations, it is appropriate to attempt to apply this methodology to the assessment of the antibiotic susceptibilities of these four mycoplasma species because of their importance in disease and because of their increasing resistance to previously active antibiotics (7,12,18,19 Ϫ1 , respectively, for ciprofloxacin; 1, 32, 64, and 8 l ml Ϫ1 , respectively, for gentamicin; 4, 4, 1, and 2 l ml Ϫ1 , respectively, for chloramphenicol; 0.25, 0.5, 0.25, and 0.25 l ml Ϫ1 , respectively, for oxytetracycline; and 0.06, 0.06, 0.03, and 0.06 l ml Ϫ1 , respectively, for tylosin. For flow cytometric analysis, the antibacterial agents were added to the pH medium at 0.125 time the MIC (1/8 MIC), the MIC (MIC), and eight times the MIC (8 MIC).…”