Four cases of resistance mutations in 23S rRNA gene in Mycoplasma pneumoniae isolated from the hospitalized military personnel

Mycoplasma pneumoniae is a bacterial pathogen cause of upper and lower respiratory tract infections, transmitted by airborne droplets, causing outbreaks of pneumonia mainly in closed groups. According with recommendations, M. pneumoniae infections can usually be effectively treated with macrolides, which are generally considered the first-choice antibiotics in young adults. However, macrolide resistance has been observed in a number of countries. Macrolide resistance phenotypes are defined by specific point mutations in the V domain of the single-copy 23S rRNA gene of M. pneumoniae, mainly at positions 2063, 2064 and 2617 (numbering according to M. pneumoniae). Identification of appropriate single nucleotide substitutions allows effectively predicting the phenotype of resistance to macrolides, but the methods used for this purpose currently are laborious and costly. The present study is devoted to the development and validation of a new method for the determination of mutations associated with macrolide resistance in M. pneumoniae, as well as its use for the analysis of clinical specimens obtained from 31 patients with pneumonia treated in a military hospital. Two and one patients had M. pneumoniae isolates with a substitution at positions 2063 and 2064, respectively. In one case, a mixed population of wild-type and mutated M. pneumoniae isolate was observed. A rare mutation variant in the 23S rRNA gene of M. pneumoniae corresponding to the genotype C2617G was found in one patient. Our PCR-RT assay is able to discriminate between wild-type and resistant genotypes of M. pneumoniae directly from clinical specimens can be used to quickly identify type of mutations and predict possible resistance respiratory mycoplasmas to macrolide antibiotics. This assay will allow clinicians to shorten the time to the initiation of effective disease treatment.