title: Adequacy of examining one sputum specimen in tuberculosis drug resistance surveys.
abstract: Collection of one spot and one morning sputum specimen is recommended for tuberculosis (TB) drug resistance surveys. This was a retrospective analysis of Mycobacterium tuberculosis cultures isolated from two spot sputum specimens collected from smear positive TB patients in a TB drug resistance survey. It was conducted to understand the value of a second specimen.
  
  
  
  A TB drug resistance survey was conducted in the state of Tamil Nadu, India, to estimate the prevalence of drug resistance among new sputum smear-positive (NSP) and previously treated (PT) patients diagnosed in Revised National Tuberculosis Control Program microscopy centers. A total of 2425 patients (1524 NSP and 901 PT cases) were enrolled in the study. From these patients, two spot sputum specimens (C and D) were collected within a period of 2h. No preservative was added to sputum. The samples were transported at ambient conditions without cold storage to the central laboratory for culture of M. tuberculosis. Culture yield from each sample was computed and analyzed.
  
  
  
  The proportion of cultures retrieved from C and D specimens among NSP cases (89.3% and 89.7%) and PT cases (90.8% and 90.3%) were similar. The culture grades of C and D samples were comparable (chi-square test, 3560.135; p<.001) and the agreement was moderate (kappa test, 0.454).
  
  
  
  The findings of the study reveal the adequacy of single spot sputum specimen from smear positive pulmonary TB patients for bacteriological examination in a quality-assured TB laboratory to determine precisely the level of drug resistance in a province of India.
authors.affiliation: Department of Bacteriology, National Institute for Research in Tuberculosis, Chetpet, Chennai - 600 031, India.
authors.forename: Subramanyam
authors.initials: S
authors.lastname: Balaji
authors.affiliation: Department of Bacteriology, National Institute for Research in Tuberculosis, Chetpet, Chennai - 600 031, India.
authors.forename: Vanaja
authors.initials: V
authors.lastname: Kumar
authors.affiliation: Department of Bacteriology, National Institute for Research in Tuberculosis, Chetpet, Chennai - 600 031, India.
authors.forename: Prabu
authors.initials: P
authors.lastname: Seenivasan
authors.affiliation: Department of Bacteriology, National Institute for Research in Tuberculosis, Chetpet, Chennai - 600 031, India.
authors.forename: R
authors.initials: R
authors.lastname: Radhakrishnan
authors.affiliation: Department of Bacteriology, National Institute for Research in Tuberculosis, Chetpet, Chennai - 600 031, India.
authors.forename: Gomathi
authors.initials: G
authors.lastname: Sekar
authors.affiliation: Department of Statistics, National Institute for Research in Tuberculosis, Chetpet, Chennai - 600 031, India.
authors.forename: Thiruvengadam
authors.initials: T
authors.lastname: Kannan
authors.affiliation: Department of Statistics, National Institute for Research in Tuberculosis, Chetpet, Chennai - 600 031, India.
authors.forename: Vedhachalam
authors.initials: V
authors.lastname: Chandrasekaran
authors.affiliation: Department of Bacteriology, National Institute for Research in Tuberculosis, Chetpet, Chennai - 600 031, India.
authors.forename: Soumya
authors.initials: S
authors.lastname: Swaminathan
authors.affiliation: Department of Bacteriology, National Institute for Research in Tuberculosis, Chetpet, Chennai - 600 031, India. Electronic address: Selvakumar.nagamiah@gmail.com.
authors.forename: Nagamiah
authors.initials: N
authors.lastname: Selvakumar
mesh_terms: D024881:Drug Resistance, Bacterial; D006801:Humans; D007194:India; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000302:isolation & purification*; D012189:Retrospective Studies; D013048:Specimen Handling / Q000379:methods*; D013183:Sputum / Q000382:microbiology*; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis* / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000382:microbiology
keywords: Drug resistance survey; Löwenstein–Jensen media; Mycobacterium tuberculosis; Sputum