Molecular and clinical characteristics of severe Mycoplasma pneumoniae pneumonia in children

Abstract

Objectives: To analyze the molecular and the clinical characteristics of Mycoplasma pneumoniae (Mp) pneumonia (MPP) and to explore the related factors predicting severe MPP (SMPP).Methods: A total of 423 pediatric cases of MPP were retrospectively analyzed, in 2013-2017, in Beijing, China. Clinical information was collected from the medical records. Mp-positive specimens were characterized using P1 typing and multiple locus variable-number tandem repeat analysis (MLVA). The macrolide resistanceassociated mutations were also detected.Results: The predominant genotype was P1-1 (88.2%) and M4-5-7-2 (87.5%), whereas percentages of type P1-2 and M3-5-6-2 increased across the 5-year period. The mutation rate of genotype M4-5-7-2 (365/370, 98.6%) was significantly higher than that of the genotype M3-5-6-2 (15/48, 32.25%; P = 0.000). Overall, 180 (42.6%) of the 423 Mp-positive patients were coinfected with other pathogens. Respiratory syncytial virus coinfection (24/180, 13.3%) was more common in cases typed M3-5-6-2 (4/23, 17.4%) than that of M4-5-7-2 (20/155, 12.9%; P = 0.038). Pleural effusion accounted for 52.6% (169/321) of the observed complications. In the mono-infection cases, cases typed M3-5-6-2 (56%, 14/25) were significantly (P = 0.020) associated with pleural effusion compared with those typed M4-5-7-2 (32.6%, 70/215); 84% (21/ 25) of specimens typed M3-5-6-2 were diagnosed as SMPP, whereas 63.7% (137/ 215) of specimens typed M4-5-7-2 were diagnosed as SMPP (P = 0.043). Conclusions:In our study, we proposed for the first time that the mono-infection patients with Mp typed M3-5-6-2 appear to have a higher risk for progressing to SMPP. MLVA typing can provide hints on the clinical characteristics of Mpp.

Evaluating the predictive value of procalcitonin, cough duration, and heat peak in severe Mycoplasma pneumoniae pneumonia

“…Patients with severe MPP had significantly increased levels of neutrophils, CRP and PCT, as well as reduced levels of lymphocytes and platelets compared to patients with general MPP. These findings are consistent Yan et al [8,16,17]. Previous studies have suggested that thrombocytopenia is an extrapulmonary manifestation of MPP [3,18].…”

“…The majority of the patients with severe MPP had a fever lasting more than 7 days, a cough lasting more than 2 weeks, and most required hospitalization for more than 7 days. Patients with general MPP had significantly shorter fever durations, cough durations, and hospitalizations compared to those with severe MPP, consistent with previous reports [8,14,15]. The Japanese Respiratory Society's scoring system provides guidance for recognizing MPP, with white blood cell (WBC) count < 10 × 10 9 /L being one of six standard parameters [3].…”

“…general MPP (n = 275) and severe MPP (n = 67). Patients with severe MPP met at least one of the following criteria: severe toxicosis symptom or dyspnea; radiological deterioration observed in more than two lobes of the lung, pleural thickening, adhesion, pleural effusion, atelectasis, or pulmonary abscess; and severe extrapulmonary complications, severe organ damage, or severe disturbance of acid-alkaline balance and electrolyte [5,[7][8][9][10]. Demographic and clinical data including age, sex, season of onset, heat peak(before admission), fever duration(before admission), cough duration(before admission), length of hospitalization (in days), and laboratory results were collected for all participants.…”

Viral and bacterial coinfection among hospitalized children with respiratory tract infections

“…5,6 MP is one of the predominant causative agents of pneumonia in children, in addition to the respiratory infection system, MP contributes to a broad array of extrapulmonary diseases, some of which can be even life-threatening. 7,8 A better understanding of the prevalence of RTIs in children is essential for implementing an effective approach for prevention, control, and treatment, because of lacking vaccines for most of these respiratory pathogens, especially MP.…”

Identify clinical factors related to Mycoplasma pneumoniae pneumonia with hypoxia in children

“…At present, there are few studies on MPP with hypoxia. However, the current theory of excessive immune response causing MPP disease progression is generally accepted [20][21][22][23] . In the laboratory indicators, the level of WBC, neutrophil ratio, CRP, LDH, IL-6 and ferritin were related to MPP with hypoxia, which was similar to the previous case reports [24][25][26] .…”