OBJECTIVETo analyze the molecular characters of the W135 Neisseria meningitidis strain firstly isolated from patients in Guangdong province.

METHODSBiochemical profile by using the API NH system (bio-Merieux, France) was used for confirmation,and sero-grouping of the meningococcal isolates including one serogroup W135, one serogroup C and three serogroups of a Neisseria meningitidis isolated from patients in Guangdong province in recent two years were performed. The subtype was determined after amplifying porA and porB respectively from the genome DNA of Neisseria meningitidis. Multilocus sequence typing (MLST) was performed for determining the allele profiles and the sequence types (STs). The polygenetic tree was obtained by analyzing the allele profiles with program Splits tree online. The molecular characters of the serogroup W135 Neisseria meningitidis was analyzed by its evolution relationship and the variable regions in porA and porB which encoding the outer membranes proteins (OMPs).

RESULTSThe subtype determined by porA variable regions of the serogroup W135 Neisseria meningitidis was P1.5,2, which was one of the most invasive types. The types of variable regions (VRs) I, IV, V, VII with porB were 1, 1, 1, 17, and there was no VI and VIII in porB. The allele profile of the W135 strain in this study was 2, 123, 4, 3, 8, 4, 6, and its sequence type was ST-2960, which belonged to ST-11/ET-37 clone complex. The subtypes of the serogroup C and serogroup A strains were P1.20, while their types of VR IV were all 7, and they all hadn't VR VII in porB. The strain serogroup C belonged to ST-4821 clone complex, and the 3 serogroup A strains belonged to ST-5 clone complex.

CONCLUSIONThe molecular character of the serogroup W135 Neisseria meningitidis should be the same with the strains isolated in foreign country, and be different from the epidemic types in the area. This serogroup W135 Neisseria meningitis isolated from patients in Guangdong for the first time was thought to be a new type appearing in the local area.