title: Direct Detection by the Xpert MTB/RIF Assay and Characterization of Multi and Poly Drug-Resistant Tuberculosis in Guinea-Bissau, West Africa.
abstract: BACKGROUND
  This study aimed to evaluate the usefulness of the Xpert MTB/RIF assay for the rapid direct detection of M. tuberculosis complex (MTBC) strains and rifampicin resistance associated mutations in a resource-limited setting such as Guinea-Bissau and its implications in the management of tuberculosis (TB) and drug resistant tuberculosis, complementing the scarce information on resistance and genotypic diversity of MTBC strains in this West African country.
  
  
  RESULTS
  This cross-sectional prospective study included 100 consecutive TB patients with positive acid-fast smears at two months of anti-tuberculosis treatment or in a re-treatment situation, between May and December 2012. Resistance to rifampicin was detected using the GeneXpert system and the Xpert MTB/RIF assay. MTBC isolates obtained with the BACTEC MGIT 960 system were tested for susceptibility to first- and second-line anti-tuberculosis drugs. Overall, the prevalence of multidrug-resistant tuberculosis (MDR-TB) was found to be 9 cases. Of these, 67% (6 patients) of confirmed MDR-TB cases had no past history of TB treatment and 33% (3 patients) were previously treated cases. Extensively drug-resistant TB was not found. Molecular typing of the MDR-TB strains revealed recent transmission patterns of imported MDR strains.
  
  
  CONCLUSIONS
  The Xpert MTB/RIF assay was reliable for the detection of rifampicin resistant MTBC strains directly from sputum samples of patients undergoing first-line treatment for two months, being more trustworthy than the simple presence of acid-fast bacilli in the smear. Its implementation is technically simple, does not require specialized laboratory infrastructures and is suitable for resource-limited settings when a regular source of electricity and maintenance is available as well as financial and operation sustainability is guaranteed by the health authorities. A high prevalence of MDR-TB among patients at risk of MDR-TB after two months of first-line treatment was found, in support of the WHO recommendations for its use in the management of this risk group.
authors.affiliation: Instituto Nacional de Saúde Pública/Projecto de Saúde de Bandim (INASA/PSB), Bissau, Guiné-Bissau.
authors.forename: Paulo
authors.initials: P
authors.lastname: Rabna
authors.affiliation: Grupo de Micobactérias, Unidade de Microbiologia Médica, Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa (IHMT, UNL), Lisboa, Portugal.
authors.forename: Jorge
authors.initials: J
authors.lastname: Ramos
authors.affiliation: Unidade de Clínica Tropical, Instituto de Higiene e Medicina Tropical de Lisboa/Universidade NOVA de Lisboa (IHMT/UNL), Lisboa, Portugal.
authors.forename: Gema
authors.initials: G
authors.lastname: Ponce
authors.affiliation: Instituto Nacional de Saúde Pública/Projecto de Saúde de Bandim (INASA/PSB), Bissau, Guiné-Bissau.
authors.forename: Lilica
authors.initials: L
authors.lastname: Sanca
authors.affiliation: Instituto Nacional de Saúde Pública/Projecto de Saúde de Bandim (INASA/PSB), Bissau, Guiné-Bissau.
authors.forename: Morto
authors.initials: M
authors.lastname: Mané
authors.affiliation: Grupo de Micobactérias, Unidade de Microbiologia Médica, Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa (IHMT, UNL), Lisboa, Portugal; Centro de Malária e Outras Doenças Tropicais (CMDT), Instituto de Higiene e Medicina Tropical de Lisboa/Universidade NOVA de Lisboa (IHMT/UNL), Lisboa, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Armada
authors.affiliation: Grupo de Micobactérias, Unidade de Microbiologia Médica, Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa (IHMT, UNL), Lisboa, Portugal.
authors.forename: Diana
authors.initials: D
authors.lastname: Machado
authors.affiliation: Hospital Raoul Follereau, Bissau, Guiné-Bissau.
authors.forename: Fina
authors.initials: F
authors.lastname: Vieira
authors.affiliation: Ministério da Saúde/Programa Nacional de Luta contra a Tuberculose, Bissau, Guiné-Bissau.
authors.forename: Victor F
authors.initials: VF
authors.lastname: Gomes
authors.affiliation: Hospital Raoul Follereau, Bissau, Guiné-Bissau.
authors.forename: Elisabete
authors.initials: E
authors.lastname: Martins
authors.affiliation: Aid, Health and Development-Onlus-Ahead-Onlus, Rome, Italy.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Colombatti
authors.affiliation: Aid, Health and Development-Onlus-Ahead-Onlus, Rome, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Riccardi
authors.affiliation: Centro de Patogénese Molecular, URIA, Faculdade de Farmácia, Universidade de Lisboa, Lisboa, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Perdigão
authors.affiliation: Centro de Patogénese Molecular, URIA, Faculdade de Farmácia, Universidade de Lisboa, Lisboa, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Sotero
authors.affiliation: Centro de Patogénese Molecular, URIA, Faculdade de Farmácia, Universidade de Lisboa, Lisboa, Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Portugal
authors.affiliation: Grupo de Micobactérias, Unidade de Microbiologia Médica, Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa (IHMT, UNL), Lisboa, Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Couto
authors.affiliation: Unidade de Clínica Tropical, Instituto de Higiene e Medicina Tropical de Lisboa/Universidade NOVA de Lisboa (IHMT/UNL), Lisboa, Portugal; Centro de Malária e Outras Doenças Tropicais (CMDT), Instituto de Higiene e Medicina Tropical de Lisboa/Universidade NOVA de Lisboa (IHMT/UNL), Lisboa, Portugal.
authors.forename: Jorge
authors.initials: J
authors.lastname: Atouguia
authors.affiliation: Instituto Nacional de Saúde Pública/Projecto de Saúde de Bandim (INASA/PSB), Bissau, Guiné-Bissau.
authors.forename: Amabélia
authors.initials: A
authors.lastname: Rodrigues
authors.affiliation: Grupo de Micobactérias, Unidade de Microbiologia Médica, Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa (IHMT, UNL), Lisboa, Portugal; Centro de Malária e Outras Doenças Tropicais (CMDT), Instituto de Higiene e Medicina Tropical de Lisboa/Universidade NOVA de Lisboa (IHMT/UNL), Lisboa, Portugal.
authors.forename: Miguel
authors.initials: M
authors.lastname: Viveiros
mesh_terms: D000328:Adult; D000995:Antitubercular Agents / Q000494:pharmacology* / Q000627:therapeutic use; D003430:Cross-Sectional Studies; D005260:Female; D005838:Genotype; D006169:Guinea-Bissau / Q000453:epidemiology; D006801:Humans; D008297:Male; D058889:Molecular Typing; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D018579:Patient Selection; D012293:Rifampin / Q000494:pharmacology* / Q000627:therapeutic use; D012306:Risk; D013997:Time Factors; D018088:Tuberculosis, Multidrug-Resistant / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*
chemical_list: D000995:Antitubercular Agents; D012293:Rifampin