Introduction
Mycoplasma pneumoniae is one of the most common causes of acute respiratory tract infection(ARTI) and community-acquired pneumonia(CAP) especially in children. About 20%~40% of CAP in pediatric department is infected by M.pneumoniae .1, 2 The infection is transmitted through close contact with infected patients, which may leads to epidemics in family and community. Global M.pneumoniaeepidemics occur every 3 to 7 years with various incidence rates. Studies show that an epidemic has been spreading in many countries since 2010.3-6 Upper and lower respiratory tract infections are often mild and self-limited; however, sometimes occasional complications in other organs may develop to death.
M. pneumoniae naturally lacks a cell wall as the action position, it is resistance to β-lactam antibiotics such as penicillin and cephalosporin. Macrolides are usually the first pharmaceuticals to treat children with CAP caused by M. pneumonia . However, long time excessive use of macrolides provided condition for macrolide-resistantM. pneumoniae (MRMP) strains in the world. Since 2000,the first case of MRMP strains was reported , MRMP has spread rapidly worldwide, especially in East Asia.7, 8It was reported that the resistant rates reach to about 90% in China and Japan. Several point mutations on the 23s RNA account for the macrolide-resistant of M. pneumoniae . The most common mutation sites were A2063 andA2064 which usually induce high-level macrolide-resistant, the mutation site at C2617 was related to low-level macrolide-resistant.7
For a long time, the PCR product length analysis of the P1 gene has been the most common molecular typing method. However, this method can only classified
M. pneumonia strains into two groups. In 2009, D’egrange et al. published a new method—multiple-locus variable-number tandem repeat (VNTR) analysis (MLVA). This method remarkably increases the typing groups for M. pneumoniaeand provides a new powerful tool for the epidemicology of M. pneumoniae infections. 9In 2011,Dumke et al. developed the MLVA method.10 The original project was based on VNTR at five loci on the 23s RNA. One loci named Mpn1 was finally excluded because of the instability problem in recent proposal project. 10-12
The aim of this study is to explore the relation between MLVA types and macrolide-resistant of M. pneumonia in children in Henan province, which might provide some interesting information for studying the emergence of MRMP in Henan province and other regions.