Clinical features of Mycoplasma pneumoniae infection in respiratory tract in children in middle south of China

Mycoplasma pneumoniae (MP) is the smallest microorganisms which can survive independently in the world. It is a pathogen between the bacteria and the virus, mainly violates the respiratory system. Nasopharyngeal aspirates were collected from children with respiratory infection from April 2013 to November 2016 in a hospital in Jiangxi, China. A total of 4350 children were enrolled and nine viruses and eight bacteria, including MP, were tested by polymerase chain reaction (PCR) and culture. The total positivity rate of any viruses and bacteria was 73.6%; bacteria-positive detection rate was 34.5%; virus-positive detection rate was 49.1%; and mixed-positive detection rate was 45.4%. A total of 596 cases were identified as MP-positive, among which 274 cases were MP-positive only. MP was detected throughout the year and across all age groups. When compared with those of the respiratory syncytial virus (RSV)-positive only group, the MP-positive only group was consisted of older children and presented a higher percentage of fever, a longer duration of fever, and a lower percentage of wheezing. High load of MP-positive only group was detected mainly in preschool and school-aged children. Longer fever duration and severe cough symptoms were observed in the high load of MP-positive only group with high levels of C-reactive protein (CRP), lactate dehydrogenase (LDH), erythrocyte sedimentation rate (ESR), and D-dimer. The MP-positive only group with high load could be an etiological agent of severe respiratory tract infections.