title: Study of efflux pump gene expression in rifampicin-monoresistant Mycobacterium tuberculosis clinical isolates.
abstract: Rifampicin (RIF) resistance is a risk factor for poor outcome in tuberculosis (TB). In Mycobacterium tuberculosis, both target gene mutation and efflux pumps have major roles in the resistance to anti-TB drugs. This study aimed to determine whether RIF induces efflux pump activation in RIF-monoresistant M. tuberculosis strains. Here, we took advantage of 16 RIF-monoresistant M. tuberculosis clinical isolates to evaluate the expression of 27 putative drug efflux pump genes and measured the influence of four drug efflux pump inhibitors, carbonyl cyanide m-chlorophenyl hydrazone (CCCP), verapamil (VP), thioridazine (TZ) and chlorpromazine (CPZ), on the RIF MICs of these strains. Eight of the 16 RIF-monoresistant isolates carried mutations in rpoB and overexpressed one or two of the following putative efflux pump genes: Rv2333, drrB, drrC, Rv0842, bacA and efpA. CCCP, VP, TZ and CPZ lowered the RIF MICs greater than fourfold in 6, 12, 9 and 12 isolates, respectively. The lowered RIF MICs by VP and CPZ were identical and stronger than CCCP (P-values were all 0.033). In conclusion, the efflux pumps Rv2333, DrrB, DrrC, Rv0842, BacA and EfpA may have a role in RIF resistance in addition to classical mutations in the rpoB gene, and the addition of VP and CPZ could significantly increase RIF susceptibility in RIF-monoresistant M. tuberculosis.
authors.affiliation: 1] Tuberculosis branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China [2] Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Guilian
authors.initials: G
authors.lastname: Li
authors.affiliation: 1] Tuberculosis branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China [2] Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China [3] Key Lab of Laboratory Medicine, Wenzhou Medical College, Wenzhou, Zhejiang, China [4] Laboratory, Gynecological and Obstetric Hospital in Shi Jiazhuang, Hebei, China.
authors.forename: Jingrui
authors.initials: J
authors.lastname: Zhang
authors.affiliation: 1] Tuberculosis branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China [2] Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China [3] Pathogenic Biology Institute, South of China University, Hengyang, Hunan, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Guo
authors.affiliation: 1] Tuberculosis branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China [2] Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China [3] Key Lab of Laboratory Medicine, Wenzhou Medical College, Wenzhou, Zhejiang, China.
authors.forename: Jianhao
authors.initials: J
authors.lastname: Wei
authors.affiliation: 1] Tuberculosis branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China [2] Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: 1] Tuberculosis branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China [2] Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Xiuqin
authors.initials: X
authors.lastname: Zhao
authors.affiliation: 1] Tuberculosis branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China [2] Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Zhao
authors.affiliation: 1] Tuberculosis branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China [2] Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Zhiguang
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Key Lab of Laboratory Medicine, Wenzhou Medical College, Wenzhou, Zhejiang, China.
authors.forename: Jianxin
authors.initials: J
authors.lastname: Lu
authors.affiliation: 1] Tuberculosis branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China [2] Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Kanglin
authors.initials: K
authors.lastname: Wan
mesh_terms: D000328:Adult; D000995:Antitubercular Agents / Q000494:pharmacology*; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D024881:Drug Resistance, Bacterial; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D006801:Humans; D026901:Membrane Transport Proteins / Q000096:biosynthesis* / Q000235:genetics; D008826:Microbial Sensitivity Tests; D020125:Mutation, Missense; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D012293:Rifampin / Q000494:pharmacology*; D018088:Tuberculosis, Multidrug-Resistant / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D026901:Membrane Transport Proteins; D012321:DNA-Directed RNA Polymerases; C105078:RNA polymerase beta subunit; D012293:Rifampin