title: Diagnostic yield of nontuberculous mycobacteria in patients booked for endoscopy at the University Teaching Hospital, Lusaka.
abstract: BACKGROUND
  The intestinal carriage of nontuberculous mycobacteria (NTM) is associated with disease, especially in severely immunocompromised individuals. These organisms, although often considered contaminants, have been known to cause various types of illnesses. We aimed to determine the prevalence of and associated factors for NTM among patients booked for colonoscopy at the University Teaching Hospital (UTH) in Lusaka.
  
  
  METHODS
  We randomly recruited 97 patients attending routine endoscopy procedures between November 2012 and October 2013 and after consent, administered a structured questionnaire. We collected stool and intestinal lavage samples, as well as biopsy samples from the descending colon and the caecal area during the endoscopy procedure. Samples were cultured using the mycobacteria growth indicator tube (MGIT) method followed by the GenoType Mycobacterium CM/AS assay for identification of NTM. Results were expressed as means and standard deviations; proportions were expressed as percentages with corresponding 95% confidence intervals. We used Fisher's exact Chi square test for cross-tabulations where appropriate. All statistical tests were two-sided, with a significance level set at p < 0.05.
  
  
  RESULTS
  Out of the 97 patients, 45 (46.4%) were female and 52 (53.6%) were males with mean ages 49.1 (±16.7, range 24-85) and 44.4 (±15.0, range 18-80) years respectively. The prevalence of NTM was 7.2% (95% CI 1.9-12.4), while that of Mycobacterium tuberculosis (MTB) was 6.2% (95% CI 2.3-13.0). Carriage of NTM was not significantly associated with age, sex or presenting symptoms such as diarrhoea, abdominal pain, weight loss as well as HIV status. There were no identifiable predictors of NTM carriage.
  
  
  CONCLUSIONS
  The results have shown that NTM and MTB are present in the intestines of the patients booked for colonoscopy at the University Teaching Hospital in Lusaka, but their presence is not related to presenting symptoms. Given that this may be an indicator of a bigger burden of NTM in this population, there is a need to explore this burden and the contribution it could have on abdominal disease in general as well as examine potential factors that might be important predictors.
authors.affiliation: Department of Public Health, School of Medicine, University of Zambia, Box 50110, Lusaka, Zambia. gchongwe@gmail.com.
authors.forename: Gershom
authors.identifier: http://orcid.org/0000-0003-3303-308X
authors.initials: G
authors.lastname: Chongwe
authors.affiliation: Department of Public Health, School of Medicine, University of Zambia, Box 50110, Lusaka, Zambia.
authors.forename: Charles
authors.initials: C
authors.lastname: Michelo
authors.affiliation: Tropical Gastroenterology Unit, School of Medicine, Department of Internal Medicine, University of Zambia, Box 50110, Lusaka, Zambia.|Barts and The London School of Medicine and Dentistry, London, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Kelly
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D003113:Colonoscopy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009165:Mycobacterium Infections, Nontuberculous / Q000175:diagnosis*; D009170:Nontuberculous Mycobacteria / Q000302:isolation & purification*; D015995:Prevalence; D011795:Surveys and Questionnaires; D015024:Zambia
keywords: Colonoscopy; Endoscopy; Gastrointestinal; Nontuberculous mycobacteria