c Mycoplasma pneumoniae is a major human respiratory pathogen causing both upper and lower respiratory disease in humans of all ages, and it can also result in other serious extrapulmonary sequelae. A multilocus sequence typing (MLST) scheme for M. pneumoniae was developed based on the sequences of eight housekeeping genes (ppa, pgm, gyrB, gmk, glyA, atpA, arcC, and adk) and applied to 55 M. pneumoniae clinical isolates and the two type strains M129 and FH. A total of 12 sequence types (STs) resulted for 57 M. pneumoniae isolates tested, with a discriminatory index of 0.21 STs per isolate. The MLST loci used in this scheme were shown to be stable in 10 strains following 10 sequential subculture passages. Phylogenetic analysis of concatenated sequences of the eight loci indicated two distinct genetic clusters that were directly linked to multilocus variable-number tandem repeat analysis (MLVA) type. Genetic MLST clustering was confirmed by genomic sequence analysis, indicating that the MLST scheme developed in this study is representative of the genome. Furthermore, this MLST scheme was shown to be more discriminatory than both MLVA and P1 typing for the M. pneumoniae isolates examined, providing a method for further and more detailed analysis of observed epidemic peaks of M. pneumoniae infection. This scheme is supported by a public Web-based database (http://pubmlst.org/mpneumoniae).
Mycoplasma pneumoniae is a common cause of communityacquired pneumonia (CAP) transmitted by aerosol or close contact (1). M. pneumoniae may cause other serious extrapulmonary sequelae, such as encephalitis (2). The pathogen is found in all age groups, with a higher prevalence in children age 5 to 14 years (3, 4). Admissions to a United Kingdom hospital in patients with CAP that were attributed to M. pneumoniae were estimated at 18% in 1982 and 4% in 1999 (5). Major increases and decreases in M. pneumoniae infection have occurred periodically in the United Kingdom; historically, epidemics have occurred at approximately 4-year intervals and have lasted 12 to 15 months, concurrent with sporadic infection at a lower level and seasonal peaks from December to February (4, 6). However, globally, peaks of infection have been observed in either summer or autumn, with no obvious explanation for this seasonal variation (7-10).Typing of clinical isolates by molecular methods is of importance for the understanding of the epidemiology of M. pneumoniae infection and for an analysis of endemic outbreaks. It is generally considered that molecular typing of M. pneumoniae is hampered by the fact that the pathogen is a genetically homologous species (11). Initial molecular typing targeted the gene encoding the major surface protein (P1) of M. pneumoniae. PCRrestriction fragment length polymorphism (PCR-RFLP) analysis of the P1 gene, which encodes a major adhesion, is the most common genotyping method. This enables the separation of isolates into two types, 1 and 2 (11-13). More recent studies utilize the repetitive regions, RepMp2/3 and RepMp4, which ...