OBJECTIVETyping of Mycobacterium tuberculosis strains and epidemiological studies in the army of southern China to provide scientific basis for prevention of pulmonary tuberculosis.

METHODSA rapid fingerprinting of M. tuberculosis strains method by polymerase chain reaction (PCR) with outward-directed primers that designed to the ends of the insertion sequence IS6110 was developed, and to analyze the relationship between the polymorphism of DNA fingerprinting and epidemiology of M. tuberculosis.

RESULTSOne hundred and fifty-four M. tuberculosis detected were classified into eight types according to their characters of PCR amplified fingerprints. The main types were type I (36.4%), type II (31.8%), and type III (21.4%), while other types were less than 4 percentage. In those main type groups, patients aged 20 to 29 and 30 to 39 took up 31.8% and 27.9% respectively. For those main types, the distribution of those types in the first treated patients showed significant difference compared with that in the retreated patients, and the rate of drug-resistance was also statistically different. However, the distribution was not statistically significant to history of BCG vaccination and patients living in urban or rural area. The main drug-resistant strains were only Isoniazid-resistant or Rifampin-resistant strains, while the drug-resistant strains were 44.4%, 29.6% and 14.8% respectively in type I, type II and type III.

CONCLUSIONPCR fingerprinting was a rapid, precise, sensitive, specific method to type M. tuberculosis, and could be used to study the epidemiology of tuberculosis; The prevalence of tuberculosis was primarily due to the transmission of type I, type II and type III in the army being studied from Southern China, to suggest that surveillance needs to be strengthened.