Comparison of a DNA based PCR method with conventional methods for the detection of M. tuberculosis in Jos, Nigeria

Ani, Agatha; Okpe, Silvanis; Akambi, Maxwell; Ejelionu, Emeka; Yakubu, Bitrus; Owolodun, Olajide Adewale; Ekeh, Peter P.; Oche, Agbaji; Tyen, Dinchi; Idoko, John

doi:10.3855/jidc.420

Cited by 24 publications

(29 citation statements)

References 22 publications

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“…The suboptimal extraction of nucleic acids was addressed in our study by the detection of human beta-globin DNA in all extraction products. From non-TB patients, real-time PCR was positive in 2/43 cases (4.6%), and this false positivity may due to laboratory contamination [8].…”

Section: Discussionmentioning

confidence: 99%

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Utility of an interferon-gamma release assay as a potential diagnostic aid for active pulmonary tuberculosis

Taki-Eddin

Monem

2011

J Infect Dev Ctries

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Introduction: Sensitivity, specificity, early confirmation and obtaining an optimal specimen are challenging problems in active tuberculosis (TB) diagnosis. Interferon-gamma release assay (IGRA) is a good indicator for latent TB but can it be useful as a diagnostic tool for active TB? This study was designed to address these challenges and assess the potential of IGRA as a diagnostic indicator of active pulmonary TB by comparing it with other MT diagnostic conventional methods and molecular methods. Methodology: The study was conducted on 91 patients with suspicion of pulmonary active TB. QuantiFERON-TB-Gold In-Tube, a commercial IFN-gamma assay, was compared with Ziehl Neelsen (ZN) smear, Lowenstein Jensen's (LJ) egg-based culture, and real-time polymerase chain reaction. The final clinical diagnosis was the standard comparator of the study. Results: Active pulmonary TB was confirmed in 48/91 (52.7%) patients. Sensitivity, specificity, positive predicted value (PPV), and negative predicted value (NPV) were 72.9%, 100%, 100%, 76.78% for ZN smear, 77.1%, 97.67%, 97.36%, 79.24% for LJ culture, 89.9%, 67.4%, 75.4%, 85.3% for IGRA, and 66.6%, 95.3%, 94.1%, 71.9% for real-time PCR, respectively. Conclusion: Albeit confounding in the case of latent TB infected patients presenting with non-TB pulmonary disease, IGRA was more sensitive than the other conventional and molecular methods, so it may improve diagnostic accuracy when used in combination with other standard methods. High NPV of IGRA for the diagnosis of active TB proposed an additional role of this test to exclude the infection with active TB.

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Section: Discussionmentioning

confidence: 99%

“…Five TB cases 5/48 (10.41%) were positive by culture and negative by IGRA. Negative IGRA and real-time PCR in three out of these five cases may be due to other mycobacterial species which require additional identification tests on LJ isolates [8].…”

Section: Discussionmentioning

confidence: 99%

Utility of an interferon-gamma release assay as a potential diagnostic aid for active pulmonary tuberculosis

Taki-Eddin

Monem

2011

J Infect Dev Ctries

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“…For example, a recent study conducted in Nigeria revealed an initial sensitivity of only 23%. 6 Moreover, a second examination of sputum smears can increase TB detection. 7 No DOTS-negative and rats-negative samples were examined by APOPO's microscopists and it is unclear how many new cases would have been detected if they had examined the same number of slides as in the present study (3,012), but selected those slides at random from the 20,614 DOTSnegative slides.…”

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confidence: 99%

Using Giant African Pouched Rats to Detect Tuberculosis in Human Sputum Samples: 2009 Findings

Poling¹,

Weetjens²,

Cox³

et al. 2010

The American Society of Tropical Medicine and Hygiene

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Tuberculosis is a major public health problem in developing countries, 1 where sputum smear microscopy is the most common technique for diagnosing the disease. This method has limitations, the most serious being inaccuracy, when large numbers of sputum samples are analyzed.2 Hence, alternative diagnostic tools are badly needed. In recent years, researchers have explored the possibility of using trained giant African pouched rats ( Cricetomys gambianus ), to screen sputum samples rapidly and accurately. A recent study 3 reported that 18 of 20 pouched rats could detect the presence of Mycobacterium tuberculosis in sputum samples at least as well as, and more quickly than, trained microscopists using the standard Ziehl Neelsen (ZN) method. 3In 2009, the rats analyzed sputum samples collected from five Direct Observation Treatment Short-Course (DOTS) centers in Dar es Salaam, Tanzania.4 Sputum samples were used to prepare microscope slides that were stained by the ZN method and evaluated under light microscopes by technicians at the DOTS centers. Sputum remaining after smears were prepared was frozen and the samples were sent to Anti-Persoonsmijnen Ontmijnende Product Ontwikkeling (APOPO) for subsequent analysis by the rats. Thus, the rats were used in a context that approximated second-line tuberculosis (TB) screening. This work describes their performance in that capacity.Ethical clearance to conduct the reported research was obtained from the Tanzanian National Institute for Medical Research. The manner in which rats were maintained, trained, and used in evaluating sputum samples is detailed elsewhere. 3,5 In brief, they were rewarded with a mouthful of banana for pausing at sputum samples known to contain M. tuberculosis but not for pausing at other sputum samples. Through such training, they learned to pause reliably only at samples that were positive for TB. In simulated second-line screening the rats worked in a 10-hole stainless steel cage 205 cm long, 55 cm wide, and 55 cm high, shown elsewhere.3 Sputum samples obtained from the DOTS centers and autoclaved to kill infectious microorganisms were presented in small pots located immediately below the holes. The status of samples with respect to microscopy was known and the rats were rewarded with food when they kept their nose in a hole above a TB-positive sample for at least 5 seconds, which defines an indicator response. Indicator responses to samples deemed by microscopists to be TB-negative were of particular interest, because such responses may indicate detection of TB-positive cases initially missed by the DOTS centers.Ten rats evaluated every sample. Any sample reported as TB-negative by a DOTS center but TB-positive by two or more rats was evaluated by a second ZN microscopic analysis performed by a technician in our laboratory. Those cases found positive in this analysis were designated as new case detections. They were reported to the appropriate DOTS Centers for follow-up testing and, if appropriate, treatment.In 2009, 23,101 sputum samples from 10,...

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“…Several studies showed similar results to our study (21)(22)(23). However, some studies reported a lower sensitivity of about 20% to 50% (20,21,24). In fact, the procedures used for bacilloscopy by such studies, were all rather indirect smear microscopy tests and the variety in their sensitivity may have been due to common laboratory errors.…”

Section: Discussionmentioning

confidence: 99%

Comparison of the culture and PCR methods for diagnosis of Mycobacterium tuberculosis in different clinical specimens

Gholoobi

Meshkat

2011

Clinical Biochemistry

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Comparison of a DNA based PCR method with conventional methods for the detection of M. tuberculosis in Jos, Nigeria

Cited by 24 publications

References 22 publications

Utility of an interferon-gamma release assay as a potential diagnostic aid for active pulmonary tuberculosis

Utility of an interferon-gamma release assay as a potential diagnostic aid for active pulmonary tuberculosis

Using Giant African Pouched Rats to Detect Tuberculosis in Human Sputum Samples: 2009 Findings

Comparison of the culture and PCR methods for diagnosis of Mycobacterium tuberculosis in different clinical specimens

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