title: Use of the Xpert(®) MTB/RIF assay for diagnosing pulmonary tuberculosis comorbidity and multidrug-resistant TB in obstetrics and gynaecology inpatient wards at the University Teaching Hospital, Lusaka, Zambia.
abstract: OBJECTIVE
  In high-tuberculosis (TB)-endemic countries, comorbidity of pulmonary TB in hospitalised patients with non-communicable diseases is well documented. In this study, we evaluated the use of the Xpert(®) MTB/RIF assay for the detection of concomitant pulmonary TB in patients admitted to the University Teaching Hospital, Lusaka, Zambia, with a primary obstetric or gynaecological condition.
  
  
  METHODS
  The Study population were inpatients admitted with a primary obstetric or gynaecological problem who had a concomitant cough and were able to expectorate a sputum sample. Sputum samples from 94 patients were analysed for the presence of Mycobacterium tuberculosis (M.tb) by standard smear microscopy, MGIT culture, MGIT drug-susceptibility testing (DST) and the Xpert(®) MTB/RIF assay. The sensitivity and specificity of the Xpert(®) MTB/RIF assay were evaluated against the culture gold standard.
  
  
  RESULTS
  Twenty-six of 94 (27.7%) patients had culture-confirmed pulmonary TB. The Xpert(®) MTB/RIF assay had a sensitivity of 80.8% [95% CI: 60.0-92.7%]) compared against MGIT culture. The Xpert(®) MTB/RIF assay was more sensitive than sputum smear microscopy (21/26 (80.8%) vs. 13/26 (50.0%), P = 0.02) and detected an additional eight culture-confirmed cases. Culture DST analysis identified two monoresistant M.tb strains: one resistant to rifampicin (rifampicin sensitive by the Xpert(®) MTB/RIF assay) and one to ethambutol. HIV infection was linked with a 3-fold increase in risk of TB, accounting for 87.5% (21/24) of TB cases. 50% of cases presented as comorbidities with other communicable diseases (CDs) and non-communicable diseases (NCDs).
  
  
  CONCLUSIONS
  As an alternative to sputum microscopy, the Xpert(®) MTB/RIF assay provides a sensitive, specific and rapid method for the diagnosis of pulmonary TB in obstetric or gynaecological inpatients. Pulmonary TB is an important cause of concomitant comorbidity to the obstetric or gynaecological condition necessitating admission. TB and HIV comorbidities with other communicable and non-communicable diseases were also common. More proactive screening for TB comorbidity is required in obstetric and gynaecological wards.
authors.affiliation: Center for Clinical Microbiology, University College, London, UK.|University of Zambia and University College London Medical School Research and Training Programme, Lusaka, Zambia.
authors.forename: Matthew
authors.initials: M
authors.lastname: Bates
authors.affiliation: Department of Obstetrics and Gynaecology, University Teaching Hospital, Lusaka, Zambia.
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Ahmed
authors.affiliation: University of Zambia and University College London Medical School Research and Training Programme, Lusaka, Zambia.
authors.forename: Lophina
authors.initials: L
authors.lastname: Chilukutu
authors.affiliation: University of Zambia and University College London Medical School Research and Training Programme, Lusaka, Zambia.
authors.forename: John
authors.initials: J
authors.lastname: Tembo
authors.affiliation: University of Zambia and University College London Medical School Research and Training Programme, Lusaka, Zambia.
authors.forename: Busiku
authors.initials: B
authors.lastname: Cheelo
authors.affiliation: Department of Paediatrics and Child Health, University Teaching Hospital, Lusaka, Zambia.
authors.forename: Sylvester
authors.initials: S
authors.lastname: Sinyangwe
authors.affiliation: University of Zambia and University College London Medical School Research and Training Programme, Lusaka, Zambia.|National Tuberculosis Control Programme, Ministry of Health, Lusaka, Zambia.
authors.forename: Nathan
authors.initials: N
authors.lastname: Kapata
authors.affiliation: Department of Tumour Immunology and Microbiology, Karolinska Institute, Stockholm, Sweden.
authors.forename: Markus
authors.initials: M
authors.lastname: Maeurer
authors.affiliation: Center for Clinical Microbiology, University College, London, UK.|University of Zambia and University College London Medical School Research and Training Programme, Lusaka, Zambia.
authors.forename: Justin
authors.initials: J
authors.lastname: O'Grady
authors.affiliation: University of Zambia and University College London Medical School Research and Training Programme, Lusaka, Zambia.|Ministry of Health, Lusaka, Zambia.
authors.forename: Peter
authors.initials: P
authors.lastname: Mwaba
authors.affiliation: Center for Clinical Microbiology, University College, London, UK.|University of Zambia and University College London Medical School Research and Training Programme, Lusaka, Zambia.
authors.forename: Alimuddin
authors.initials: A
authors.lastname: Zumla
mesh_terms: D000328:Adult; D001431:Bacteriological Techniques / Q000295:instrumentation / Q000379:methods; D015897:Comorbidity; D005260:Female; D005831:Genital Diseases, Female / Q000175:diagnosis / Q000453:epidemiology; D015658:HIV Infections / Q000175:diagnosis / Q000453:epidemiology; D006801:Humans; D007297:Inpatients / Q000706:statistics & numerical data; D008826:Microbial Sensitivity Tests / Q000295:instrumentation / Q000379:methods*; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification; D009775:Obstetrics and Gynecology Department, Hospital / Q000706:statistics & numerical data*; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000175:diagnosis / Q000453:epidemiology; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis* / Q000453:epidemiology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000453:epidemiology; D055815:Young Adult; D015024:Zambia / Q000453:epidemiology
keywords: MDR-TB; Xpert® MTB/RIF assay; gynaecology; maternal; multidrug-resistant TB; obstetric; sensitivity; specificity; sub-Saharan Africa; tuberculosis; women