Predictive value of the acid fast smear for detection of Mycobacterium tuberculosis in respiratory specimens in a Reference Center of HIV/Aids in Rio de Janeiro, Brazil

Conde, Marcus Barreto; Figueira, Cesar M; Moraes, Renata Simões; Fonseca, Leila de Souza; DeRiemer, Kathryn; Kritski, Afrânio Lineu

doi:10.1590/s0074-02761999000600014

Cited by 25 publications

(17 citation statements)

References 16 publications

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“…Among the few studies done in Brazil, in two mycobacterial isolation was performed only from sterile sites. On the other hand, in the same hospital used in our study, Conde et al (1999) reported lower occurrence of NTM (5.8% x 15% in the present study), however their analyses focused mainly on respiratory specimens. In contrast to the M. tuberculosis findings, most of our NTM isolates were obtained from sterile sites (57.8%), which confirm the dissemination characteristic of NTM infection in Aids patient, since 72.4% of them were HIV co-infected.…”

Section: Discussioncontrasting

confidence: 61%

Non-tuberculous mycobacteria I: one year clinical isolates identification in Tertiary Hospital Aids Reference Center, Rio de Janeiro, Brazil, in pre highly active antiretroviral therapy era

Ferreira

Saad

Silva³

et al. 2002

Mem. Inst. Oswaldo Cruz

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Section: Discussioncontrasting

confidence: 61%

Non-tuberculous mycobacteria I: one year clinical isolates identification in Tertiary Hospital Aids Reference Center, Rio de Janeiro, Brazil, in pre highly active antiretroviral therapy era

Ferreira

Saad

Silva³

et al. 2002

Mem. Inst. Oswaldo Cruz

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“…A total of 236 specimens were analyzed during the initial phase, and an additional 120 specimens were analyzed using the modified protocol. Each specimen with a volume of 5 ml or greater was split and processed by the standard digestion-decontamination method that combines N-acetyl-L-cysteine (NALC) and sodium hydroxide (NALC-NaOH) (3,10,15) and by the CB-18 method.…”

Section: Methodsmentioning

confidence: 99%

“…Smear microscopy is currently the most feasible microbiological method for diagnosis of pulmonary TB in developing countries due to its rapidity, low cost, and high positive predictive value for Mycobacterium tuberculosis (3). However, sputum smear microscopy with ZiehlNeelsen staining is only 60 to 70% sensitive for the diagnosis of pulmonary TB compared with sputum culture (2,8).…”

mentioning

confidence: 99%

Comparison of C ₁₈ -Carboxypropylbetaine and Standard N -Acetyl- l -Cysteine-NaOH Processing of Respiratory Specimens for Increasing Tuberculosis Smear Sensitivity in Brazil

et al. 2002

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Techniques to improve the sensitivity of smear microscopy would facilitate early tuberculosis (TB) diagnosis and disease control, especially in low-income countries where the positive predictive value is high. C 18 -carboxypropylbetaine (CB-18) is a zwitterionic detergent that helps to compensate for the innate buoyancy of mycobacteria, potentially enhancing recovery by centrifugation. Previous data suggest that CB-18 may increase the sensitivity of smear, culture, and molecular amplification diagnostic testing. The goal of the present study was to evaluate if the sensitivity of the smear technique using light microscopy could be improved by treating respiratory samples with CB-18. In the first phase, respiratory specimens were collected consecutively from patients with suspected pulmonary tuberculosis in a tertiary-care hospital in Rio de Janeiro, Brazil (236 specimens were analyzed). After protocol modifications, another 120 respiratory specimens were evaluated. The standard technique was N-acetyl-L-cysteine with sodium hydroxide (NALC-NaOH) treatment, smear concentration with centrifugation, and Ziehl-Neelsen staining. Culture on Löwenstein-Jensen slants was performed on all specimens for use as the "gold standard." No specimens from patients undergoing active TB treatment were included. The initial protocol for CB-18 processing resulted in a sensitivity of 59.6% and specificity of 96.8% compared to standard processing with a sensitivity of 66.0% and specificity of 96.8%. Using the modified protocol, the sensitivity of CB-18 increased to 71.4% with a specificity of 97.0% versus standard processing with a sensitivity of 61.9% and a specificity of 99.0%. The diagnostic yield of acid-fast bacillus smear with CB-18 in the absence of fluorescence microscopy and PCR compared to standard processing with NALC-NaOH was not significantly different, although the power to detect a difference by the modified assay was low.Tuberculosis (TB) remains one of the deadliest diseases worldwide, with an estimated 8.4 million new cases and over 2 million deaths each year (21). Smear microscopy is currently the most feasible microbiological method for diagnosis of pulmonary TB in developing countries due to its rapidity, low cost, and high positive predictive value for Mycobacterium tuberculosis (3). However, sputum smear microscopy with ZiehlNeelsen staining is only 60 to 70% sensitive for the diagnosis of pulmonary TB compared with sputum culture (2, 8). Among human immunodeficiency virus-infected persons the sensitivity of sputum Ziehl-Neelsen smears has been reported to be even lower (2, 6, 10). Delayed or missed diagnoses contribute to M. tuberculosis transmission and mortality due to TB (9, 11).Improvements in the sensitivity of smear microscopy would allow earlier diagnosis. TB programs could then optimize disease control from a public health standpoint as well as improve individual patient management (20). In previously published reports, homogenization and concentration of respiratory specimens by centrifugation have been ...

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“…Specimen culture was undertaken for 209 patients (36.0%) and was positive in 68.4%. Although less specific than specimen culture, direct bacilloscopy is a reliable test with a high positive preditive value (98.4% in sputum samples and 96.4% in bronchoalveolar lavage samples) for tuberculosis infection 22 . Despite the challenges at our hospital, only 3.5% of tuberculosis cases had the diagnosis clarified at necropsy (data found in notification forms).…”

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confidence: 97%

Clinical and epidemiological features of AIDS/tuberculosis comorbidity

et al. 2003

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Considering the relevance of AIDS/tuberculosis comorbidity worldwide, especially in Brazil, this study was developed to describe the clinical and epidemiological features of the comorbid cases identified from 1989 to 1997 by the epidemiology service of the Hospital das Clínicas of the Universidade de São Paulo.METHODS: Databases containing information on all identified AIDS/tuberculosis cases cared for at the hospital were used to gather information on comorbid cases.RESULTS: During the period, 559 patients were identified as presenting with AIDS/tuberculosis comorbidity. Risk behavior for AIDS was primarily heterosexual contact (38.9%), followed by intravenous drug use (29.3%) and homosexual/ bisexual contact (23.2%). Regarding clinical features, there were higher rates of extrapulmonary tuberculosis when compared to tuberculosis without comorbidity. There was an increase in reporting of AIDS by ambulatory units during the period. Epidemiologically, there was a decrease in the male/female ratio, a predominance in the 20 to 39 year-old age group, and a majority of individuals who had less than 8 years of schooling and had low professional qualifications.CONCLUSIONS: High rates of AIDS/tuberculosis cases at our hospital indicate the need for better attention towards early detection of tuberculosis, especially in its extrapulmonary form. Since the population that attends this hospital tends to be of a lower socioeconomic status, better management of AIDS and tuberculosis is required to increase the rates of treatment adherence and thus lower the social costs.

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Predictive value of the acid fast smear for detection of Mycobacterium tuberculosis in respiratory specimens in a Reference Center of HIV/Aids in Rio de Janeiro, Brazil

Abstract: In order to evaluate the predictive value of acid fast bacilii (AFB) smear for the diagnosis of

Cited by 25 publications

References 16 publications

Non-tuberculous mycobacteria I: one year clinical isolates identification in Tertiary Hospital Aids Reference Center, Rio de Janeiro, Brazil, in pre highly active antiretroviral therapy era

Non-tuberculous mycobacteria I: one year clinical isolates identification in Tertiary Hospital Aids Reference Center, Rio de Janeiro, Brazil, in pre highly active antiretroviral therapy era

Comparison of C ₁₈ -Carboxypropylbetaine and Standard N -Acetyl- l -Cysteine-NaOH Processing of Respiratory Specimens for Increasing Tuberculosis Smear Sensitivity in Brazil

Clinical and epidemiological features of AIDS/tuberculosis comorbidity

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Predictive value of the acid fast smear for detection of Mycobacterium tuberculosis in respiratory specimens in a Reference Center of HIV/Aids in Rio de Janeiro, Brazil

Abstract: In order to evaluate the predictive value of acid fast bacilii (AFB) smear for the diagnosis of

Cited by 25 publications

References 16 publications

Non-tuberculous mycobacteria I: one year clinical isolates identification in Tertiary Hospital Aids Reference Center, Rio de Janeiro, Brazil, in pre highly active antiretroviral therapy era

Non-tuberculous mycobacteria I: one year clinical isolates identification in Tertiary Hospital Aids Reference Center, Rio de Janeiro, Brazil, in pre highly active antiretroviral therapy era

Comparison of C 18 -Carboxypropylbetaine and Standard N -Acetyl- l -Cysteine-NaOH Processing of Respiratory Specimens for Increasing Tuberculosis Smear Sensitivity in Brazil

Clinical and epidemiological features of AIDS/tuberculosis comorbidity

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Comparison of C ₁₈ -Carboxypropylbetaine and Standard N -Acetyl- l -Cysteine-NaOH Processing of Respiratory Specimens for Increasing Tuberculosis Smear Sensitivity in Brazil