title: Optimising Mycobacterium tuberculosis detection in resource limited settings.
abstract: OBJECTIVE
  The light-emitting diode (LED) fluorescence microscopy has made acid-fast bacilli (AFB) detection faster and efficient although its optimal performance in resource-limited settings is still being studied. We assessed the optimal performances of light and fluorescence microscopy in routine conditions of a resource-limited setting and evaluated the digestion time for sputum samples for maximum yield of positive cultures.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Facility-based involving samples of routine patients receiving tuberculosis treatment and care from the main tuberculosis case referral centre in northern Nigeria.
  
  
  METHODS
  The study included 450 sputum samples from 150 new patients with clinical diagnosis of pulmonary tuberculosis.
  
  
  METHODS
  The 450 samples were pooled into 150 specimens, examined independently with mercury vapour lamp (FM), LED CysCope (CY) and Primo Star iLED (PiLED) fluorescence microscopies, and with the Ziehl-Neelsen (ZN) microscopy to assess the performance of each technique compared with liquid culture. The cultured specimens were decontaminated with BD Mycoprep (4% NaOH-1% NLAC and 2.9% sodium citrate) for 10, 15 and 20 min before incubation in Mycobacterium growth incubator tube (MGIT) system and growth examined for acid-fast bacilli (AFB).
  
  
  RESULTS
  Of the 150 specimens examined by direct microscopy: 44 (29%), 60 (40%), 49 (33%) and 64 (43%) were AFB positive by ZN, FM, CY and iLED microscopy, respectively. Digestion of sputum samples for 10, 15 and 20 min yielded mycobacterial growth in 72 (48%), 81 (54%) and 68 (45%) of the digested samples, respectively, after incubation in the MGIT system.
  
  
  CONCLUSIONS
  In routine laboratory conditions of a resource-limited setting, our study has demonstrated the superiority of fluorescence microscopy over the conventional ZN technique. Digestion of sputum samples for 15 min yielded more positive cultures.
authors.affiliation: Institute of Human Virology, Abuja, FCT, Nigeria.
authors.forename: Nwofor
authors.initials: N
authors.lastname: Alfred
authors.forename: Lawson
authors.initials: L
authors.lastname: Lovette
authors.forename: Gambo
authors.initials: G
authors.lastname: Aliyu
authors.forename: Obasanya
authors.initials: O
authors.lastname: Olusegun
authors.forename: Panwal
authors.initials: P
authors.lastname: Meshak
authors.forename: Tunkat
authors.initials: T
authors.lastname: Jilang
authors.forename: Mosunmola
authors.initials: M
authors.lastname: Iwakun
authors.forename: Emenyonu
authors.initials: E
authors.lastname: Nnamdi
authors.forename: Onuoha
authors.initials: O
authors.lastname: Olubunmi
authors.forename: Patrick
authors.initials: P
authors.lastname: Dakum
authors.forename: Alash'le
authors.initials: A
authors.lastname: Abimiku
mesh_terms: D003430:Cross-Sectional Studies; D006295:Health Resources; D006801:Humans; D008168:Lung / Q000382:microbiology*; D008856:Microscopy, Fluorescence / Q000379:methods*; D009169:Mycobacterium tuberculosis / Q000254:growth & development*; D009549:Nigeria; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000382:microbiology
keywords: Microbiology