Beijing genotype of Mycobacterium tuberculosis is less associated with drug resistance in south China.

Mycobacterium tuberculosis Beijing genotype strains are widespread globally. However, there has been no systematic study on the association between Beijing genotype and the characteristics of drug resistance. In this study, 359 M. tuberculosis isolates from south China were collected and their background information, genotype diversity and drug resistance was investigated. The results revealed that 66.0% of strains (237/359) were categorised as Beijing genotype. There was no statistical difference between Beijing and non-Beijing genotype strains in terms of patient sex, age, place of residence and treatment history. Drug resistance testing showed that 34.8% (125/359) of isolates were resistant to at least one of the seven drugs tested. The proportions of multidrug-resistant tuberculosis and extensively drug-resistant tuberculosis were 17.0% and 1.4%, respectively. Previously treated patients presented a significantly higher risk of developing drug resistance than new cases. Although the prevalence of drug resistance was higher in Beijing genotype than in non-Beijing genotype strains, there was no significant difference between these two genotypes in the multivariate analysis. Even in re-treated patients, the association of Beijing genotype with drug resistance was not significant. This study provides an insight into genotype diversity and demonstrates the characteristics of drug resistance in Beijing genotype strains, which will be useful in generating efficient tuberculosis prevention and control strategies in China.