Prevalence and clinical characteristics of hospitalized children with community-acquired Mycoplasma pneumoniae pneumonia during 2017/2018, Chengde, China

Community acquired-pneumonia (CAP) has varying causative pathogens and clinical characteristics. This study investigated the prevalence of Mycoplasma pneumoniae (M pneumoniae) and evaluated the clinical characteristics in infected hospitalized children by disease severity. From throat swabs of hospitalized children (5 months to 14 years) with CAP collected between November 2017 and May 2018, M pneumoniae and other CAP pathogens were identified using polymerase chain reaction (PCR). Differences in clinical and laboratory test data were compared between severe and mild case groups. Of 333 hospitalized children enrolled, 221/333 (66.4%) tested positive for M pneumoniae and 24/221 (10.9%) patients were (n = 9, aged <5 years vs n = 15, ≥5 years) single infection by PCR, however, only 170/333 (51.1%) patients were presented with M pneumoniae IgM-positive. M pneumoniae detection rate by PCR was higher than by immunoglobulin (IgM) serology. In 123/221 (55.7%) M pneumoniae infected patients, coinfection with bacterial pathogens (n = 61, <5 years vs n = 62, ≥5 years) occurred. Children (aged 3–8 years) had most M pneumoniae infection. Severe M pneumoniae pneumonia (MPP) in children occurred mostly in older age (7 [interquartile ranges {IQR}, 6–8] years; P < .0001), with longer cough days (14 [IQR, 10–19.5] days; P = .002) and hospitalization duration (9.5 [IQR, 7–12.3] days; P < .0001), lower lymphocyte ratio (24.1, [IQR, 20.0–31.1] %; P = .001), higher neutrophils ratio (66.0, [IQR, 60.2–70.3]%; P < .0001), and serum C-reactive protein (CRP) level (3.8, [IQR, 1.3–10.9] mg/L; P = .027). M pneumoniae is the most commonly detected pathogen in CAP. High coinfection prevalence increases diagnosis difficulty by clinically nonspecific characteristics. M pneumoniae detection by PCR with IgM may improve precise and reliable diagnosis of community-acquired MPP.