The clinical characteristics of adult patients with community acquired pneumonia caused by acute Mycoplasma ;pneumoniae infection：a multicentre cross-sectional study / 中华危重病急救医学

ABSTRACT

Objective To investigate the clinical characteristics of adult patients with community acquired pneumonia (CAP) caused by acute Mycoplasma pneumoniae (MP) infection, and provide evidence for early identification of MP infection. Methods A prospective, multicenter and cross-sectional study was conducted. 452 adult patients with CAP admitted to Beijing Friendship Hospital, Beijing Guangwai Hospital and Air Force General Hospital from August 2011 to October 2015 were enrolled. The diagnosis of adult MP infection was confirmed by the combined application of double serum antibody titer and MP-DNA nested polymerase chain reaction (PCR) through testing serum and throat swab samples from patients to identify acute infections, past infections, pathogen carrying, and non-MP infection. The clinical characteristics of patients with acute MP infection were summarized by analyzing the baseline data, clinical parameters and chest imaging findings in patients with non-MP infection and acute MP infection. Results Of 452 enrolling patients with CAP, 288 patients (63.7%) suffered from MP infection, and 164 patients (36.3%) with non-MP infection. There were 56 patients (12.4%) with acute infection, 10 patients (2.2%) with past infections, 222 patients (49.1%) with pathogen carriers in MP infective patients indicating susceptible to MP in adult patients. There were no significant differences in gender, age, fever extent, duration of fever, sputum production, shortness of breath, rales, underlying diseases, etc. between non-MP infection and acute MP infection patients, which suggested that the baseline data of the two groups were equilibrium. The acute infection rates of MP in summer and autumn (43.9% and 43.5% respectively) were more than those in spring and winter (13.3% and 12.3% respectively). It was shown by laboratory examination results that serum cardiac troponin T (cTnT) increased significantly in acute MP infectious patients more than that in non-MP infection patients (30.4% vs. 9.8%, P < 0.01), which indicated that patients with acute MP infection were more likely to have myocardial injury. While there were no significant differences in blood routine, blood electrolytes, blood glucose, as well as heart, liver and kidney function between the two groups. It was shown by chest imaging that the diffuse lesions (57.1% vs. 37.2%), mediastinal lymphadenopathy (60.7% vs. 37.8%) were less founded in the middle lobe of the right lung (12.5% vs. 32.9%), which were the main manifestations in patients with acute MP infection as compared with non-MP infection patients with statistical difference (all P < 0.01). There were no significant differences in the chest imaging performances of pulmonary ground glass shadow, lobar and segmental consolidation, patch shadow, a shadow, acinar nodules, grinding glass density nodules, the photic zone, hilar lymphadenopathy and pleural effusion occurrence between the two groups. Conclusion Adult CAP patients are easy to carry MP, myocardial damage is a common complication in acute MP infectious patients which are characteristic of image findings of diffuse lung disease, mediastinal lymphadenopathy and less founded in the middle lobe of the right lung.