Comparison of acid-fast stain and culture for Mycobacterium tuberculosis in pre- and post-bronchoscopy sputum and bronchoalveolar lavage in HIV-infected patients with atypical chest X-ray in Ethiopia

Abstract

BACKGROUND:Smear-negative tuberculosis occurs more frequently in human immunodeficiency virus (HIV)-infected patients than in non-HIV-infected patients. Besides, there are substantial numbers of patients who cannot produce sputum, making the diagnosis of pulmonary tuberculosis (PTB) difficult.AIMS:To evaluate the relative yield of pre- and post-bronchoscopy sputum and bronchoalveolar lavage (BAL) in ‘sputum smear’-negative, HIV-positive patients.SETTINGS:A tertiary care referral hospital in Addis Ababa.MATERIALS AND METHODS:Acid-fast stain (AFS) using the concentration technique was done on 85 pre-bronchoscopy sputum and 120 BAL samples. Direct AFS was done on all BAL and 117 post-bronchoscopy sputum samples. Culture for Mycobacterium tuberculosis (MTB) was done for all sputa and BAL.RESULTS:MTB was isolated from 26 (21.7%), 23 (19.7%) and 13 (15.3%) of BAL, post- and pre-bronchoscopy sputum cultures respectively. AFS on pre-bronchoscopy sputum using concentration technique and direct AFS on BAL together detected 11 (41%) of the 27 culture-positive cases. In patients who could produce sputum, the sensitivity of pre-bronchoscopy sputum culture (13/85, 15.3%) was comparable to BAL (12/85, 14%) and post-bronchoscopy sputum (12/85, 14%). In patients who could not produce sputum, however, both BAL (12/35, 40%) and post-bronchoscopy sputum (12/32, 31.4%) detected significantly more patients than those who could produce sputum (P=0.002, P=0.028 respectively).CONCLUSION:In HIV-infected patients, AFS by concentration method on pre-bronchoscopy sputum and direct AFS on BAL in patients who cannot produce sputum are the preferred methods of making a rapid diagnosis. BAL culture seems to add little value in patients who can produce sputum; therefore, bronchoscopy should be deferred under such circumstances.

Committee II: Guidelines for cytologic sampling techniques of lung and mediastinal lymph nodes

“…24 Postbronchoscopy sputum analysis can increase diagnostic yield in patients who are smear negative or non-productive of sputum. 25,26 Once transbronchial exfoliative samples are retrieved, the patient is placed in the supine position while the selector catheter is in position and 10 mL of sterile saline are rapidly injected. The catheter is then withdrawn and the patient turned on his side with the affected lung being uppermost.…”

“…A post‐bronchoscopy sputum smear may be helpful in combination with bronchoalveolar lavage (BAL) particularly for the detection of pulmonary TB in patients with suspected pulmonary TB who had either three negative sputum smears or could not expectorate . Post‐bronchoscopy sputum analysis can increase diagnostic yield in patients who are smear negative or non‐productive of sputum …”

Laboratory diagnostic systems used in the diagnosis of tuberculosis in Ethiopia: A systematic review

“…Of the 267 citations identified by literature searches, a total of 33 English-language publications (32 articles, and 1 population based survey) met the eligibility criteria (Figure 1). Of the 33 studies, ten (30.3%) studies utilized culture (Aderaye et al, 2003(Aderaye et al, , 2007Alebachew et al, 2011;Beyene et al, 2008;Shah et al, 2009;Bruchfeld et al, 2002;Abebe et al, 2010Abebe et al, , 2012Legesse et al, 2011) and one study employed polymerase chain reaction (PCR) as the reference standard (Beyene et al, 2009). Eighteen (54.5%) studies used a cross sectional study design, three (9.1%) used comparative, two (6.1%) used a retrospective design, two (6.1%) randomized trial and one (3%) did not describe the study design employed method.…”

“…Twenty-four (72.73%) of the 33 studies utilized ZN stained microscopy and three 3 (9.4%) studies used light emitting diodes fluorescent microscope (LED-FM). Four (12.15%) reported the use of some processing methods (Aderaye et al, 2007;Ali et al, 2012), three (9.14%) studies used tuberculin skin tests (TST) and QuantiFERON-TB gold In-Tube (QFTGIT) together and two (6.13%) studies employed cytological techniques. Chest X-ray was employed in the majority of studies, especially for smear negative results with symptomatic patients suggestive of tuberculosis.…”

Detection of Mycobacterium tuberculosis in sputum in patients coinfected with HIV / tuberculosis by various methods (literature review)

“…Исследова-ние мокроты у пациентов до и после выполнения фибробронхоскопии, а также посевы бронхо-аль-веолярной лаважной жидкости не повышают чув-ствительность культурального исследования в ус-ловиях высокой распространенности олиобацил-лярного ТБ среди ЛЖВ [46]. В последние годы в научной литературе достаточ-но активно обсуждается сравнительный анализ ин-формативности выявления МБТ у больных коинфек-цией (ВИЧ-и/ТБ) в сравнении с ВИЧ-негативными пациентами молекулярно-генетическими методами.…”