Study of Two Separate Types of Macrolide-Resistant Mycoplasma pneumoniae Outbreaks.

To study the complete natural process of a Mycoplasma pneumoniae outbreak in a semiclosed room such as a primary school room, we investigated two separate M. pneumoniae outbreaks involving 81 students in total in two primary schools in Hangzhou, China. M. pneumoniae isolates from pharyngeal swabs were detected by fluorescence quantitative real-time PCR (RT-PCR) and culture. The class in school M had 39 students, with 12 (30.8%) with positive M. pneumoniae detection results. The class from school J had 42 students, with 13 (31.0%) positive. The strains from two classes were confirmed to represent two clones (3/4/5/7/2 and 5/4/5/7/2) and to be macrolide resistant (A2063G) according to P1 and multilocus variable-number tandem-repeat analysis (MLVA) genotyping, determination of MIC of antibiotics, and sequencing. Students with M. pneumoniae isolates detected were divided into three groups: those carrying the isolates, those with upper respiratory tract infection (URI), and those with pneumonia. Longitudinal sampling performed using pharyngeal swabs showed that the persistence of M. pneumoniae was longest in the group of students with pneumonia. M. pneumoniae causes pneumonia outbreaks in schools, and the incidence of pneumonia has a higher rate than that of URI. The persistence of M. pneumoniae, with a median duration of 79.50 days in the group of students with pneumonia, differs from that of the infection state.