[Molecular detection and genotyping of Mycoplasma pneumoniae in 220 children hospitalized with pneumonia].

OBJECTIVE

To investigate the infection rate and genotypes of Mycoplasma pneumoniae (MP) by examining bronchoalveolar lavage fluid from children with community acquired pneumonia (CAP).

METHODS

Polymerase chain reaction (PCR) was used for detecting MP in bronchoalveolar lavage fluid from 220 children hospitalized with CAP, and the accuracy was confirmed by quantitative real-time PCR. Positive samples were digested with HaeⅡ and Hae Ⅲ and compared with standard strain to analyze the genotypes of MP from positive samples. The accuracy of genotyping was confirmed by sequencing the amplified products of some randomly selected positive samples.

RESULTS

The positive rate of MP in 220 samples was 55.0% (121/220). MP infection occurred mostly in preschool and school-age children (63.5%, 101/159), and the lowest positive rate was seen in children aged under 6 months (20%, 1/5). The positive rate showed no significant differences between sexes and between seasons. Sixty randomly selected MP-positive samples showed a genotype of P1 type 1 after restriction digestion, which was further confirmed by sequencing of 4 samples.

CONCLUSIONS

MP is one of the main pathogens of pneumonia in children, and the MP infection rate is significantly correlated with age. The dominant genotype of MP in children is P1 type 1.