H M Adnan Hameed1,2, Yaoju Tan3, Md Mahmudul Islam1,2, Lingmin Guo1,2, Chiranjibi Chhotaray1,2, Shuai Wang1,2, Zhiyong Liu1, Yamin Gao1,2, Shouyong Tan3, Wing Wai Yew4, Nanshan Zhong5, Jianxiong Liu3, Tianyu Zhang1,2,5. 1. State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health (GIBH), Chinese Academy of Sciences (CAS), Guangzhou 510530, China. 2. University of Chinese Academy of Sciences (UCAS), Beijing 100049, China. 3. State Key Laboratory of Respiratory Disease, Guangzhou Chest Hospital, Guangzhou 510095, China. 4. Stanley Ho Centre for Emerging Infectious Diseases, The Chinese University of Hong Kong, Hong Kong, China. 5. State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510182, China.
Abstract
BACKGROUND: Levofloxacin (LVX) and Moxifloxacin (MXF) are the cornerstones for treatment of multidrug-resistant tuberculosis (MDR-TB). China is one of the highest MDR- and fluoroquinolones (FQ)-resistant TB burdens countries. DNA gyrase encoded by gyr genes is the main target of FQ in Mycobacterium tuberculosis (MTB). The prevalence and molecular characterization of LVX- and MXF-resistant MTB strains from southern China were examined in this study. METHODS: Drug susceptibility testing (DST) of 400 MTB clinical isolates was evaluated by proportion method on Löwenstein-Jensen (LJ) medium against ten drugs. The sequencing of entire gyrA and gyrB genes and multiplex PCR were performed to distinguish the prevalence of mutant types in Beijing and non-Beijing genotypes. RESULTS: Three hundred and twenty-one out of four hundred (80.25%) drug-resistant isolates (resistant > one drug) were categorized as 83/321 (25.80%) MDR, 174/321 (54.20%) pre-XDR and 64/321 (19.93%) XDR-MTB. Overall, 303/400 (75.75%) LVX- and 292/400 (73.00%) MXF-resistant (R) MTB strains were identified. Two hundred seventy-one out of three hundred and three (89.43%) resistant strains carried mutations in gyrA and 91/303 (30.03%) in gyrB. Interestingly, 18 novel mutations were detected in gyrA and gyrB genes. Mutations at (A90, D94) and (T500, G510, G512) frequently existed in QRDR(s) of gyrA and gyrB respectively in 286/400 (71.50%) LVXRMXFR strains. The novel mutations in- and out-side the QRDR of gyrA (L105R, A126E, M127K, D151T, V165A) and gyrB (D461H, N499S, G520A) increased the sensitivity and consistency of genotypic tests. Notably, 25 LVXRMXFR strains were found with unknown resistance mechanisms. CONCLUSIONS: Mutations in QRDR(s) were concomitantly associated with Beijing and non-Beijing genotypes. The prevalence of resistance and cross-resistance between LVX and MXF in MTB isolates from southern China was immensely higher than other countries. Our valuable findings provide the substantial implications to improve the reliability of genotypic diagnostic tests relying on potential resistance conferring mutations in entire gyr genes. 2019 Journal of Thoracic Disease. All rights reserved.
BACKGROUND: Levofloxacin (LVX) and Moxifloxacin (MXF) are the cornerstones for treatment of multidrug-resistant tuberculosis (MDR-TB). China is one of the highest MDR- and fluoroquinolones (FQ)-resistant TB burdens countries. DNA gyrase encoded by gyr genes is the main target of FQ in Mycobacterium tuberculosis (MTB). The prevalence and molecular characterization of LVX- and MXF-resistant MTB strains from southern China were examined in this study. METHODS: Drug susceptibility testing (DST) of 400 MTB clinical isolates was evaluated by proportion method on Löwenstein-Jensen (LJ) medium against ten drugs. The sequencing of entire gyrA and gyrB genes and multiplex PCR were performed to distinguish the prevalence of mutant types in Beijing and non-Beijing genotypes. RESULTS: Three hundred and twenty-one out of four hundred (80.25%) drug-resistant isolates (resistant > one drug) were categorized as 83/321 (25.80%) MDR, 174/321 (54.20%) pre-XDR and 64/321 (19.93%) XDR-MTB. Overall, 303/400 (75.75%) LVX- and 292/400 (73.00%) MXF-resistant (R) MTB strains were identified. Two hundred seventy-one out of three hundred and three (89.43%) resistant strains carried mutations in gyrA and 91/303 (30.03%) in gyrB. Interestingly, 18 novel mutations were detected in gyrA and gyrB genes. Mutations at (A90, D94) and (T500, G510, G512) frequently existed in QRDR(s) of gyrA and gyrB respectively in 286/400 (71.50%) LVXRMXFR strains. The novel mutations in- and out-side the QRDR of gyrA (L105R, A126E, M127K, D151T, V165A) and gyrB (D461H, N499S, G520A) increased the sensitivity and consistency of genotypic tests. Notably, 25 LVXRMXFR strains were found with unknown resistance mechanisms. CONCLUSIONS: Mutations in QRDR(s) were concomitantly associated with Beijing and non-Beijing genotypes. The prevalence of resistance and cross-resistance between LVX and MXF in MTB isolates from southern China was immensely higher than other countries. Our valuable findings provide the substantial implications to improve the reliability of genotypic diagnostic tests relying on potential resistance conferring mutations in entire gyr genes. 2019 Journal of Thoracic Disease. All rights reserved.
Authors: M M Islam; Y Tan; H M A Hameed; Z Liu; C Chhotaray; Y Liu; Z Lu; X Cai; Y Tang; Y Gao; G Surineni; X Li; S Tan; L Guo; X Cai; W W Yew; J Liu; N Zhong; T Zhang Journal: Clin Microbiol Infect Date: 2018-12-22 Impact factor: 8.067
Authors: Amy Sarah Ginsburg; Ronggai Sun; Heather Calamita; Cherise P Scott; William R Bishai; Jacques H Grosset Journal: Antimicrob Agents Chemother Date: 2005-09 Impact factor: 5.191
Authors: Ricky W T Lau; Pak-Leung Ho; Richard Y T Kao; Wing-Wai Yew; Terrence C K Lau; Vincent C C Cheng; Kwok-Yung Yuen; Stephen K W Tsui; Xinchun Chen; Wing-Cheong Yam Journal: Antimicrob Agents Chemother Date: 2010-10-18 Impact factor: 5.191