Transition mutations in the 23S rRNA of erythromycin-resistant isolates of Mycoplasma pneumoniae

Abstract

Erythromycin is the drug of choice for treatment of Mycoplasma pneumoniae infections due to its susceptibility to low levels of this antibiotic. After exposure of susceptible strains to erythromycin in vitro and in vivo, mutants resistant to erythromycin and other macrolides were isolated. Their phenotypes have been characterized, but the genetic basis for resistance has never been determined. We isolated two resistant mutants (M129-ER1 and M129-ER2) by growing M. pneumoniae M129 on agar containing different amounts of erythromycin. In broth dilution tests both strains displayed resistance to high levels of several macrolide-lincosamide-streptogramin B (MLS) antibiotics. In binding studies, ribosomes isolated from the resistant strains exhibited significantly lower affinity for Mycoplasma pneumoniae is a common cause of respiratory tract infections particularly in school-aged children and young adults. All levels of the respiratory tract are involved, and while the most characteristic manifestations are acute bronchitis and pneumonia (8, 11), serious complications can occur (5). The sensitivity of M. pneumoniae to erythromycin and many other macrolide antibiotics makes them the drugs of choice for chemotherapy (3, 33). Treatment with erythromycin results in relatively rapid alleviation of symptoms; however, viable M. pneumoniae can frequently be isolated from infected individuals for a prolonged period of time following therapy (6,41,45). Isolation of resistant strains from patients following treatment is not uncommon (26,28,(43)(44)(45), and erythromycinresistant mutants are readily derived by selection in vitro (27,43,44). Phenotypic studies have demonstrated that most of these strains simultaneously developed resistance to macrolide, lincosamide, and group B streptogramin (MLS) antibiotics (48). It was suspected that development of resistance to erythromycin contributed to the prolonged colonization of the respiratory tract following chemotherapy.As part of our efforts to understand what role, if any, development of antibiotic resistance may play in the course of M. pneumoniae infection, we are attempting to determine the molecular mechanisms by which resistance to erythromycin can arise. While the genetic basis for MLS resistance has been extensively studied for other bacteria, except for a rudimentary study of Ureaplasma urealyticum (30) it has not been explored in mycoplasmas. We show that MLS-type resistance in two isolates derived in vitro is correlated with A-to-G transitions at two conserved sites in the central loop in domain V of the 23S rRNA which are known to result in similar patterns of resistance in other organisms. The possible clinical implications of these mechanisms are discussed. MATERIALS AND METHODSMedia and growth conditions. M. pneumoniae M129-B16 (ATCC 33530) was grown in glass culture bottles or 96-well microtiter plates in modified Hayflick's medium (19) without penicillin. One-percent Bacto-Agar (Difco, Detroit, Mich.) was added for growth on solid medium. Antibiotics were obtained ...

The role of ribosomal RNAs in macrolide resistance

“…Only recently, mutations at 23S RNA position 2059 were found to be associated with macrolide resistance in M. avium (Meier et al, 1994), M. pneumoniae (Lucier et al, 1995), M. chelonae and M. abscessus . However, a cause-effect relationship remained to be established.…”

“…A unique mechanism of macrolide resistance has recently been demonstrated in organisms carrying a single ribosomal RNA operon, e.g. Mycobacterium avium (Meier et al, 1994;, Mycoplasma pneumoniae (Lucier et al, 1995), Mycobacterium chelonae and Mycobacterium abscessus . In these organisms, point mutations in the peptidyltransferase centre of the 23S RNA gene were found to be associated with macrolide resistance (for review, see Böttger, 1994;Sander et al, 1996a).…”

Identification of a Mutation Associated with Erythromycin Resistance in Bordetella pertussis : Implications for Surveillance of Antimicrobial Resistance

“…The transition from A to G at the position corresponding to 2058 in is the most frequent of the mutations associated with macrolide resistance in clinical isolates, including H. pylori (11,(30)(31)(32), Mycobacterium spp. (17,18,21,34), M. pneumoniae (16), and propionibacteria (24). Bias toward the A2058G-equivalent mutation has been attributed to higher MICs, greater stability of the mutation, and better strain fitness (higher growth rate) compared to other 23S mutations that confer macrolide resistance (4,21).…”

“…Methylation of A2058 can result in resistance to macrolides (14-to 16-membered rings) other than erythromycin and in cross-resistance to lincosamides and type B streptogramin antibiotics that also bind to nucleotide A2058 (36). Recently, a chromosomal mutation that alters the erythromycin binding site in domain V has been shown to confer erythromycin-resistance in a number of clinical isolates, including Helicobacter pylori, Propionibacterium sp., Mycoplasma pneumoniae, Mycobacterium avium, and Mycobacterium intracellulare (16,18,21,24,32). The most common mutation in these isolates occurs at positions cognate with the nucleotide equivalent to A2058 of the rRNA (rrn) operon encoding the 23S rRNA and typically confers the lincosamide-streptogramin B resistance phenotype (36).…”

Cluster of Macrolide-Resistant Mycoplasma pneumoniae Infections in Illinois in 2012

“…Sequencing analysis of specimens obtained from patient 3 demonstrated the presence of the A2063G transition in the 23S rRNA gene, a mutation commonly associated with macrolide resistance in M. pneumoniae (23,24). The high burden of M. pneumoniae in patient 3, as indicated by the low C T values in the detection assay, allowed the clear identification of macrolide resistance directly from the primary specimen extract without the need for an isolate.…”