Clinical features of 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.