title: Quadruple-first line drug resistance in Mycobacterium tuberculosis in Vietnam: What can we learn from genes?
abstract: In Vietnam, a country with high tuberculosis (137/100.000 population) and multidrug-resistant (MDR)-TB burdens (7.8/100.000 population), little is known about the molecular signatures of drug resistance in general and more particularly of second line drug (SLD) resistance. This study is specifically focused on Mycobacterium tuberculosis isolates resistant to four first-line drugs (FLDs) that make TB much more difficult to treat. The aim is to determine the proportion of SLD resistance in these quadruple drug resistant isolates and the genetic determinants linked to drug resistance to better understand the genetic processes leading to quadruple and extremely drug resistance (XDR). 91 quadruple (rifampicin, isoniazid, ethambutol and streptomycin) FLD resistant and 55 susceptible isolates were included. Spoligotyping and 24-locus MIRU-VNTR techniques were performed and 9 genes and promoters linked to FLD and SLD resistance were sequenced. SLD susceptibility testing was carried out on a subsample of isolates. High proportion of quadruple-FLD resistant isolates was resistant to fluoroquinolones (27%) and second-line injectable drugs (30.2%) by drug susceptibility testing. The sequencing revealed high mutation diversity with prevailing mutations at positions katG315, inhA-15, rpoB531, embB306, rrs1401, rpsL43 and gyrA94. The sensitivity and specificity were high for most drug resistances (>86%), but the sensitivity was lower for injectable drug resistances (<69%). The mutation patterns revealed 23.1% of pre-XDR and 7.7% of XDR isolates, mostly belonging to Beijing family. The genotypic diversity and the variety of mutations reflect the existence of various evolutionary paths leading to FLD and SLD resistance. Nevertheless, particular mutation patterns linked to high-level resistance and low fitness costs seem to be favored.
authors.affiliation: UMR MIVEGEC (224 IRD-5290 CNRS-Université de Montpellier), Institute of Research for Development, Montpellier, France; Department of Bacteriology, National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam; Department of Biotechnology-Pharmacology, University of Science and Technology of Hanoi, Hanoi, Viet Nam; LMI Drug Resistance in South East Asia (DRISA), NIHE, Hanoi, Viet Nam. Electronic address: huynguyen.biotech@gmail.com.
authors.forename: Huy Quang
authors.initials: HQ
authors.lastname: Nguyen
authors.affiliation: Viet Nam National Tuberculosis Programme, Hanoi, Viet Nam; Viet Nam Association for Tuberculosis and Lung Disease, Hanoi, Viet Nam.
authors.forename: Nhung Viet
authors.initials: NV
authors.lastname: Nguyen
authors.affiliation: UMR MIVEGEC (224 IRD-5290 CNRS-Université de Montpellier), Institute of Research for Development, Montpellier, France; Department of Bacteriology, National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam; LMI Drug Resistance in South East Asia (DRISA), NIHE, Hanoi, Viet Nam.
authors.forename: Lucie
authors.initials: L
authors.lastname: Contamin
authors.affiliation: Department of Bacteriology, National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam.
authors.forename: Thanh Hoa Thi
authors.initials: THT
authors.lastname: Tran
authors.affiliation: Department of Bacteriology, National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam.
authors.forename: Thuong Thi
authors.initials: TT
authors.lastname: Vu
authors.affiliation: Department of Microbiology, National Lung Hospital, Hanoi, Viet Nam.
authors.forename: Hung Van
authors.initials: HV
authors.lastname: Nguyen
authors.affiliation: Department of Microbiology, Pham Ngoc Thach Hospital, Ho Chi Minh, Viet Nam.
authors.forename: Ngoc Lan Thi
authors.initials: NLT
authors.lastname: Nguyen
authors.affiliation: Department of Microbiology, Military Medical University, Hanoi, Viet Nam.
authors.forename: Son Thai
authors.initials: ST
authors.lastname: Nguyen
authors.affiliation: Department of Bacteriology, National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam.
authors.forename: Anh Duc
authors.initials: AD
authors.lastname: Dang
authors.affiliation: UMR MIVEGEC (224 IRD-5290 CNRS-Université de Montpellier), Institute of Research for Development, Montpellier, France; Department of Bacteriology, National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam; LMI Drug Resistance in South East Asia (DRISA), NIHE, Hanoi, Viet Nam.
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Bañuls
authors.affiliation: Department of Bacteriology, National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam.
authors.forename: Van Anh Thi
authors.initials: VAT
authors.lastname: Nguyen
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D002374:Catalase / Q000235:genetics; D027081:DNA Gyrase / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004977:Ethambutol / Q000494:pharmacology; D054908:Extensively Drug-Resistant Tuberculosis / Q000382:microbiology; D015870:Gene Expression; D056084:Genetic Fitness; D014644:Genetic Variation; D006801:Humans; D007538:Isoniazid / Q000494:pharmacology; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D010088:Oxidoreductases / Q000235:genetics; D010430:Pentosyltransferases / Q000235:genetics; D012269:Ribosomal Proteins / Q000235:genetics; D012293:Rifampin / Q000494:pharmacology; D013307:Streptomycin / Q000494:pharmacology; D014744:Vietnam
chemical_list: D000995:Antitubercular Agents; D001426:Bacterial Proteins; D012269:Ribosomal Proteins; C505805:rpoB protein, Mycobacterium tuberculosis; D004977:Ethambutol; D010088:Oxidoreductases; D002374:Catalase; C480353:katG protein, Mycobacterium tuberculosis; C085257:InhA protein, Mycobacterium; C540269:EmbB protein, Mycobacterium tuberculosis; D010430:Pentosyltransferases; D012321:DNA-Directed RNA Polymerases; D027081:DNA Gyrase; D007538:Isoniazid; D012293:Rifampin; D013307:Streptomycin
keywords: Drug resistance-associated mutations; Drug susceptibility testing; Extensively drug resistance; First line drugs; MIRU-VNTR; Mycobacterium tuberculosis; Second line drugs; Spoligotyping