title: Primary drug resistance among pulmonary treatment-naïve tuberculosis patients in Amazonas State, Brazil.
abstract: BACKGROUND
  Multidrug-resistant tuberculosis (MDR-TB) is the main indicator of previous treatment in tuberculosis (TB) patients. MDR-TB among treatment-naïve patients indicates infection with drug-resistant Mycobacterium tuberculosis strains, and such cases are considered primary drug-resistant cases.
  
  
  OBJECTIVE
  To estimate the prevalence of drug resistance in pulmonary TB (PTB) treatment-naïve patients and to identify the socio-demographic and clinical characteristics of the resistant population.
  
  
  METHODS
  A total of 205 treatment-naïve PTB patients from Manaus, Amazonas State, Brazil, were enrolled. Drug susceptibility testing (DST) was performed on all positive mycobacterial cultures using the 1% proportion method.
  
  
  RESULTS
  Positive M. tuberculosis cultures were obtained from only 175 patients for DST. The prevalence of primary MDR-TB was 1.7% (3/175); 14.3% (25/175) of the cultures presented resistance to at least one of the drugs. Resistance to streptomycin, isoniazid, rifampicin and ethambutol was respectively 8.6%, 6.9%, 3.4% and 2.3%. An association between TB patients with resistance to more than one drug and known previous household contact with a TB patient was observed (P= 0.008, OR 6.7, 95%CI 1.2-67.3).
  
  
  CONCLUSIONS
  Although the prevalence of primary MDR-TB currently is relatively low, it may become a major public health problem if tailored treatment is not provided, as resistance to more than one drug is significantly associated with household contact.
authors.affiliation: Universidade do Estado do Amazonas/Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, Amazonas, Brazil.
authors.forename: M
authors.initials: M
authors.lastname: da Silva Garrido
authors.affiliation: Universidade do Estado do Amazonas/Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, Amazonas, Brazil.
authors.forename: R
authors.initials: R
authors.lastname: Ramasawmy
authors.affiliation: Universidade do Estado do Amazonas/Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, Amazonas, Brazil.
authors.forename: T M
authors.initials: TM
authors.lastname: Perez-Porcuna
authors.affiliation: Laboratório Central de Saúde Pública do Amazonas, Manaus, Amazonas, Brazil.
authors.forename: E
authors.initials: E
authors.lastname: Zaranza
authors.affiliation: Universidade do Estado do Amazonas/Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, Amazonas, Brazil.
authors.forename: A
authors.initials: A
authors.lastname: Chrusciak Talhari
authors.affiliation: Universidade do Estado do Amazonas/Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, Amazonas, Brazil.
authors.forename: F E
authors.initials: FE
authors.lastname: Martinez-Espinosa
authors.affiliation: Universidade do Estado do Amazonas/Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, Amazonas, Brazil.
authors.forename: S
authors.initials: S
authors.lastname: Bührer-Sékula
mesh_terms: D000328:Adult; D000995:Antitubercular Agents / Q000627:therapeutic use*; D001938:Brazil; D016009:Chi-Square Distribution; D016358:Contact Tracing; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000302:isolation & purification; D016017:Odds Ratio; D015995:Prevalence; D012111:Residence Characteristics; D012307:Risk Factors; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology* / Q000635:transmission; D055815:Young Adult
chemical_list: D000995:Antitubercular Agents