Objective
To analyze the epidemiological characteristics of Mycoplasma pneumoniae (MP) infection in children with respiratory tract diseases, and to provide scientific basis for clinical diagnosis and treatment and to formulate control measurements for the administrative department of public health.
Methods
Sputum specimens of 20 021 cases of hospitalized children with respiratory tract diseases from October 2005 to December 2014 in Suzhou were collected. MP DNA was detected by fluorescence quantitative polymerase chain reaction. At the same time, venous blood was collected within 24 h after admission and 7-10 d of treatment. Specified MP antibodies IgG and IgM were tested by enzyme-linked immunosorbent assay to analyze the detection rate of MP. The positive rates between groups were compared using chi-square test or Fisher exact test. Measurement data were compared using Wilcoxon test.
Results
The MP infection rate was 36.08%(7 224/20 021 cases) in 20 021 children. The MP infection rate of girls was 40.81%(3 057/7 490), which was significantly higher than that of boys (33.25%[4 167/12 531], χ2=116.20, P<0.01). The MP infection rates of children at the age of less than six months, 6 months to 1 year old, 1-3 years old, 3-7 years old and older than 7 years old were 18.35%, 29.39%, 43.93%, 54.10% and 64.48%, respectively, which increased with age (χ2=1 949.65, P<0.01). The MP infection rates in spring, summer, autumn and winter were 31.97%, 41.57%, 40.88% and 29.90%, respectively. The MP infection rate of children in summer and autumn was significantly higher than that in spring and winter (χ2=234.61, P<0.01). The MP infection rate was highest in the autumn of year 2008 (55.07%) and lowest in the spring of year 2010 (18.48%) for the decade. The MP infection rate showed fluctuations with different degrees in four seasons except in 2007. In the past ten years, the MP infection rate in Suzhou area was at a higher level in 2008, 2009, 2012 and 2013, which were 46.03%, 46.60%, 39.28% and 47.40%, respectively. The MP infection rate was the lowest (25.24%) in 2011 in the decade, and maintained around 30% in the rest years.
Conclusions
The MP infection rate in children with respiratory tract diseases is at a high level in Suzhou area. The MP infection rate of girls is higher than that of boys. MP infection could occur among all age groups, and the MP infection rate increases with age. MP infection rate peaks in summer and autumn. MP infection has a small prevalence every two or three years, which could sustain about two years.
Key words:
Pneumonia, mycoplasma; Respiratory tract diseases; Epidemiology; Child