Prevalence, risk and genetic characteristics of drug-resistant tuberculosis in a tertiary care tuberculosis hospital in China

Li-Li Zhao,*,1 Ming-Xiang Huang,*,2 Tong-Yang Xiao,1 Hai-Can Liu,1 Ma-Chao Li,1 Xiu-Qin Zhao,1 Zhi-Guang Liu,1 Yi Jiang,1 Kang-Lin Wan11State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, People’s Republic of China; 2Clinical Laboratory, Fuzhou Pulmonary Hospital, Fuzhou, 350008, People’s Republic of China*These authors contributed equally to this workObjectives: To explore the prevalence, risk and genetic characteristics of drug-resistant tuberculosis (TB) from a tertiary care TB hospital in China.Patients and methods: We carried out a retrospective study including isolates from 189 patients with pulmonary TB at Fuzhou Pulmonary Hospital. All isolates from these patients were subjected to drug susceptibility testing and genotyping. For drug-resistant isolates, DNA sequencing was used to investigate mutations in 12 loci, including katG, inhA, oxyR–ahpC, rpoB, rpsL, rrs1 (nucleotides 388–1084 of rrs), embB, tlyA, eis, rrs2 (nucleotides 1158–1674 of rrs), gyrA and gyrB.Results: Among 189 isolates, 28.6% were resistant to at least one of the seven anti-TB drugs, including isoniazid (INH), rifampin (RIF), streptomycin (STR), ethambutol (EMB), capreomycin (CAP), kanzmycin (KAN) and ofloxacin (OFX). The proportion of multidrug-resistant TB and extensively drug-resistant TB isolates was 9.5% and 1.1%, respectively. Patients in rural areas as well as previously treated patients showed a significantly increased risk of developing drug resistance. In addition, among these isolates, 111 (58.7%) were Beijing genotype strains, 84 (75.7%) of which belonged to modern Beijing sublineage. There was no association between genotype and drug resistance. The most common mutations were katG315, rpoB531 rpsL4