The yield of Auramine O staining using led microscopy with bleach treated sputum samples for detection of pulmonary tuberculosis at St. Peter tuberculosis specialized hospital, Addis Ababa, Ethiopia

Abstract

BackgroundSmear microscopy is the mainstay for diagnosis of Tuberculosis (TB) in Ethiopia. This technique; however, is insensitive to detect Mycobacteria from most clinical specimens. Currently, light emitting diode (LED) fluorescence microscope is advocated to be used in high Tuberculosis (TB) burden settings by World Health Organization (WHO). However, the utility of this method is not evaluated for bleach treated sputum samples in Ethiopia.ObjectiveThe objective of the study is to evaluate the diagnostic importance of Auramine O (AO) staining in direct and concentrated sputum against conventional Zehil-Neelsen (ZN) and culture from the sputum samples of suspected pulmonary tuberculosis patients.MethodsA cross-sectional study was conducted on 346 adult new pulmonary TB suspected patients at St. Peter's Specialized Hospital, Addis Ababa, Ethiopia. Three sputum samples (spot-morning-spot) were collected in sterile cups for direct Zehil-Neelsen and AO staining. Morning sputum samples were used for Mycobacterial culture on Mycobacterial Growth Indicator Tube (MGIT) 960. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were evaluated against the gold standard culture method. Data were analyzed using STATA version 13.0. All statistical tests were considered as statistically significant if the two sided P-value was < 0.05.ResultsBleach treated sputum samples with AO staining yielded more cases as compared to direct ZN and direct AO by 6.3% and 11.5%, respectively. The sensitivity of concentrated AO and direct AO were remarkably high as compared to conventional ZN (71.8% vs. 44.5% and 62.7% vs. 44.5%). The concentrated sputum with staining of AO had a high rate (18.6%) of detecting scanty graded smears as compared to conventional ZN method.ConclusionsOur findings indicated that the concentrated sputum with AO staining yielded high rate of sensitivity (71.8%) as compared to the conventional ZN method (44.5%). Moreover, the concentrated sputum with AO staining had superior ability in detecting scanty graded smears compared to the conventional ZN method. Therefore, it is recommended to utilize AO staining with LED microscopy for better diagnosis of Acid Fast Bacilli (AFB) from TB suspected cases and patients with pauci-bacillary TB in Ethiopia.

Auramine-O Staining vs Ziehl Neelsen Staining: Advantages and Disadvantages

“…Out of 1,503 samples, 781 (51.96%) were found to be AFB positive by ZN stain while 904 (60.15%) samples were positive by AO Staining, and 843 (56.09%) showed growth of mycobacteria on LJ Medium. A cross-sectional study done in Ethiopia by Gizaw et al 18 on 346 pulmonary TB suspected patients. They evaluated the importance of Auramine-O staining in direct and concentrated sputum against conventional ZN and mycobacterial culture on mycobacterial growth indicator tube (MGIT) 960.…”

Hierarchical true prevalence, risk factors and clinical symptoms of tuberculosis among suspects in Bangladesh

“…The overall and DOTS center level true prevalence of tuberculosis among TB suspects in Bangladesh were estimated using a shiny web-application tPRiors [ 21 ]. The sensitivity (mean = 0.627 and lower limit at 95% confidence level = 0.50) and specificity (mean = 0.987 and lower limit at 95% confidence level = 0.90) of the auramine staining and LED microscopy [ 22 ]. was used as prior information in the model.…”

Diagnostic implications and inpatient mortality related to tuberculosis at Jimma Medical Center, southwest Ethiopia

“…The use of smear microscopy is not enough to detect active TB in patients suspected of pulmonary and extra-pulmonary disease. An estimated 50% of TB cases have been missed and left untreated due to the continued use of less sensitive smear microscopy, particularly in resource-constrained countries [2] , [3] , [4] , [5] . The capacity to use culture for diagnosis of TB in all patients with a negative smear result is very scarce [3] , [6] .…”

“…An estimated 50% of TB cases have been missed and left untreated due to the continued use of less sensitive smear microscopy, particularly in resource-constrained countries [2] , [3] , [4] , [5] . The capacity to use culture for diagnosis of TB in all patients with a negative smear result is very scarce [3] , [6] . However, to overcome the diagnosis efficacy limitations, an experienced physicians initiates a full course of anti-TB treatment in smear-negative or severely ill patients according to the national guideline recommendations [7] .…”