title: First evaluation of drug-resistant Mycobacterium tuberculosis clinical isolates from Congo revealed misdetection of fluoroquinolone resistance by line probe assay due to a double substitution T80A-A90G in GyrA.
abstract: BACKGROUND
  Tuberculosis (TB) is one of the major public health problems in Congo. However, data concerning Mycobacterium tuberculosis drug resistance are lacking because of the insufficient processing capacity. So, the aim of this study was to investigate for the first time the resistance patterns and the strain lineages of a sample of M. tuberculosis complex (MTBC) isolates collected in the two main cities of Congo.
  
  
  METHODS
  Over a 9-day period, 114 smear-positive sputa isolated from 114 patients attending centers for the diagnosis and treatment of TB in Brazzaville and Pointe Noire were collected for culture and drug susceptibility testing (DST). Detection of mutations conferring drug resistance was performed by using line probe assays (GenoType MTBDRplus and MTBDRsl) and DNA sequencing. Strain lineages were determined by MIRU-VNTR genotyping.
  
  
  RESULTS
  Of the 114 sputa, 46 were culture positive for MTBC. Twenty-one (46%) were resistant to one or more first-line antiTB drugs. Of these, 15 (71%) were multidrug resistant (MDR). The most prevalent mutations involved in rifampin and isoniazid resistance, D516V (60%) in rpoB and S315T (87%) in katG respectively, were well detected by MTBDRplus assay. All the 15 MDR strains were susceptible to fluoroquinolone and injectable second-line drug. No mutation was detected in the rrs locus involved in resistance to amikacin and capreomycin by both the MTBDRsl assay and DNA sequencing. By contrast, 9 MDR strains belonging to the same cluster related to T-family were identified as being falsely resistant to fluoroquinolone by the MTBDRsl assay due to the presence of a double substitution T80A-A90G in GyrA.
  
  
  CONCLUSIONS
  Taken together, these data revealed a possible spread of a particular MDR clone in Congo, misidentified as fluoroquinolone resistant by MTBDRsl assay. Thus, this test cannot replace gold-standard culture method and should be interpreted carefully in view of the patient's native land.
authors.affiliation: UPMC Université, Paris, France; INSERM U1135, Paris, France; Centre National de Référence des Mycobactéries et de la Résistance des Mycobactéries aux Antituberculeux, Paris, France.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Aubry
authors.affiliation: UPMC Université, Paris, France; INSERM U1135, Paris, France; Centre National de Référence des Mycobactéries et de la Résistance des Mycobactéries aux Antituberculeux, Paris, France.
authors.forename: Wladimir
authors.initials: W
authors.lastname: Sougakoff
authors.affiliation: Faculté des Sciences de la Santé, Brazzaville, Congo.
authors.forename: Pamela
authors.initials: P
authors.lastname: Bodzongo
authors.affiliation: Laboratoire de Bactériologie-Hygiène du CHRU, Lille, France.
authors.forename: Guy
authors.initials: G
authors.lastname: Delcroix
authors.affiliation: Laboratoire de Bactériologie-Hygiène du CHRU, Lille, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Armand
authors.affiliation: Centre National de Référence des Mycobactéries et de la Résistance des Mycobactéries aux Antituberculeux, Paris, France.
authors.forename: Gérald
authors.initials: G
authors.lastname: Millot
authors.affiliation: UPMC Université, Paris, France; INSERM U1135, Paris, France; Centre National de Référence des Mycobactéries et de la Résistance des Mycobactéries aux Antituberculeux, Paris, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Jarlier
authors.affiliation: Laboratoire de Bactériologie-Hygiène du CHRU, Lille, France; Université Lille Nord de France, Lille, France; UDSL, F-59000 Lille, France; INSERM U1019-UMR8204, Lille, France.
authors.forename: René
authors.initials: R
authors.lastname: Courcol
authors.affiliation: Laboratoire de Bactériologie-Hygiène du CHRU, Lille, France; Université Lille Nord de France, Lille, France; UDSL, F-59000 Lille, France; INSERM U1019-UMR8204, Lille, France.
authors.forename: Nadine
authors.initials: N
authors.lastname: Lemaître
mesh_terms: D019943:Amino Acid Substitution; D003223:Congo / Q000453:epidemiology; D027081:DNA Gyrase / Q000235:genetics*; D004252:DNA Mutational Analysis; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005260:Female; D024841:Fluoroquinolones; D006801:Humans; D008297:Male; D020125:Mutation, Missense; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000302:isolation & purification; D014376:Tuberculosis / Q000453:epidemiology / Q000235:genetics
chemical_list: D024841:Fluoroquinolones; D027081:DNA Gyrase
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