title: Active tuberculosis case finding and detection of drug resistance among HIV-infected patients: A cross-sectional study in a TB endemic area, Gondar, Northwest Ethiopia.
abstract: BACKGROUND
  Tuberculosis (TB) patients co-infected with human immunodeficiency virus (HIV) often lack the classic symptoms of pulmonary tuberculosis, making the diagnosis difficult. Current practices in resource-limited settings often indicate that these co-infected patients are diagnosed when they clinically manifest disease symptoms, resulting in a delayed diagnosis and despite continued transmission. The aim of this study is to determine the prevalence of undiagnosed pulmonary tuberculosis cases through active case finding and including multidrug-resistant TB (MDR-TB) among HIV-infected patients.
  
  
  METHODS
  A total of 250 HIV-infected patients, aged 18years and above were evaluated in a cross-sectional design between February 2012 and November 2012. Socio-demographic and clinical data were collected using a structured questionnaire. Sputum samples were collected from all participants for acid fast bacilli (AFB) direct smear microscopy and Mycobacteria culture. A PCR-based RD9 deletion and genus typing, as well as first-line anti-TB drug susceptibility testing, was performed for all culture-positive isolates.
  
  
  RESULTS
  Following active TB case finding, a total of 15/250 (6%) cases were diagnosed as TB cases, of whom 9/250 (3.6%) were detected by both smear microscopy and culture and the remaining 6/250 (2.4%) only by culture. All the 15 isolates were typed through RD9 typing of which 10 were Mycobacterium tuberculosis species; 1 belonged to Mycobacterium genus and 4 isolates were non-tuberculous mycobacteria. The prevalence of undiagnosed pulmonary TB disease among the study participants was 4.4%, which implies the possibility of identifying even more undiagnosed cases through active case finding. A multivariate logistic regression showed a statistically significant association between the presence of pneumonia infection and the occurrence of TB (OR=4.81, 95% CI (1.08-21.43), p=0.04). In addition, all the isolates were sensitive to all first-line anti-TB drugs, except for streptomycin, seen in only one newly diagnosed TB patient, and MDR-TB was not detected.
  
  
  CONCLUSIONS
  The prevalence of undiagnosed pulmonary TB infection among HIV-infected patients in Gondar was 4.4%. Additionally, the possibility of these undiagnosed TB cases in the community could also pose a risk for the transmission of the disease, particularly among family members. Active screening of known HIV-infected individuals, with at least one TB symptom is recommended, even in persons with opportunistic infections.
authors.affiliation: Department of Medical Microbiology, School of Biomedical and Laboratory Sciences, University of Gondar, P.O. Box: 196, Gondar, Ethiopia; Armauer Hansen Research Institute, P.O. Box: 1005, Addis Ababa, Ethiopia. Electronic address: marthialex2011@gmail.com.
authors.forename: Martha
authors.initials: M
authors.lastname: Alemayehu
authors.affiliation: Department of Medical Microbiology, School of Biomedical and Laboratory Sciences, University of Gondar, P.O. Box: 196, Gondar, Ethiopia. Electronic address: tedybayegelaw@gmail.com.
authors.forename: Baye
authors.initials: B
authors.lastname: Gelaw
authors.affiliation: Department of Medical Microbiology, School of Biomedical and Laboratory Sciences, University of Gondar, P.O. Box: 196, Gondar, Ethiopia. Electronic address: ebbaabate@yahoo.com.
authors.forename: Ebba
authors.initials: E
authors.lastname: Abate
authors.affiliation: Armauer Hansen Research Institute, P.O. Box: 1005, Addis Ababa, Ethiopia. Electronic address: wassieliya@gmail.com.
authors.forename: Liya
authors.initials: L
authors.lastname: Wassie
authors.affiliation: Department of Medical Microbiology, School of Biomedical and Laboratory Sciences, University of Gondar, P.O. Box: 196, Gondar, Ethiopia. Electronic address: belyhun@gmail.com.
authors.forename: Yeshambel
authors.initials: Y
authors.lastname: Belyhun
authors.affiliation: Armauer Hansen Research Institute, P.O. Box: 1005, Addis Ababa, Ethiopia. Electronic address: shiferawbekele@gmail.com.
authors.forename: Shiferaw
authors.initials: S
authors.lastname: Bekele
authors.affiliation: School of Medicine, Division of Infectious Diseases, Emory University, Atlanta, GA 30303, USA. Electronic address: rkempke@emory.edu.
authors.forename: Russell R
authors.initials: RR
authors.lastname: Kempker
authors.affiliation: School of Medicine, Division of Infectious Diseases, Emory University, Atlanta, GA 30303, USA. Electronic address: hblumbe@emory.edu.
authors.forename: Henry M
authors.initials: HM
authors.lastname: Blumberg
authors.affiliation: Armauer Hansen Research Institute, P.O. Box: 1005, Addis Ababa, Ethiopia. Electronic address: aseffaa@gmail.com.
authors.forename: Abraham
authors.initials: A
authors.lastname: Aseffa
keywords: Active case finding; Drug resistance; HIV; Northwest Ethiopia; TB