Molecular Detection and Characterization of Mycoplasma pneumoniae Among Patients Hospitalized With Community-Acquired Pneumonia in the United States.

Diaz MH1, Benitez AJ1, Cross KE1, Hicks LA1, Kutty P1, Bramley AM2, Chappell JD3, Hymas W4, Patel A5, Qi C6, Williams DJ7, Arnold SR5, Ampofo K4, Self WH3, Grijalva CG3, Anderson EJ8, McCullers JA9, Pavia AT4, Wunderink RG6, Edwards KM7, Jain S2, Winchell JM1.

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Abstract

Background. Mycoplasma pneumoniae is a common cause of community-acquired pneumonia (CAP). The molecular characteristics of M pneumoniae detected in patients hospitalized with CAP in the United States are poorly described. Methods. We performed molecular characterization of M pneumoniae in nasopharyngeal/oropharyngeal swabs from children and adults hospitalized with CAP in the Centers for Disease Control and Prevention Etiology of Pneumonia in the Community (EPIC) study, including P1 typing, multilocus variable-number tandem-repeat analysis (MLVA), and macrolide susceptibility genotyping. Results. Of 216 M pneumoniae polymerase chain reaction-positive specimens, 40 (18.5%) were obtained from adults and 176 (81.5%) from children. P1 type distribution differed between adults (64% type 1 and 36% type 2) and children (84% type 1, 13% type 2, and 3% variant) (P < .05) and among sites (P < .01). Significant differences in the proportions of MLVA types 4/5/7/2 and 3/5/6/2 were also observed by age group (P < .01) and site (P < .01). A macrolide-resistant genotype was identified in 7 (3.5%) specimens, 5 of which were from patients who had recently received macrolide therapy. No significant differences in clinical characteristics were identified among patients with various strain types or between macrolide-resistant and -sensitive M pneumoniae infections. Conclusions. The P1 type 1 genotype and MLVA type 4/5/7/2 predominated, but there were differences between children and adults and among sites. Macrolide resistance was rare. Differences in strain types did not appear to be associated with differences in clinical outcomes. Whole genome sequencing of M pneumoniae may help identify better ways to characterize strains.