Although the multi-copy and specific element IS6110 provides a good target for the detection of Mycobacterium tuberculosis complex by PCR techniques, the emergence of IS6110-negative strains suggested that false negative may occur if IS6110 alone is used as the target for detection. In this report, a multiplex polymerase chain reaction (mPCR) system was developed using primers derived from the insertion sequence IS6110 and an IS-like elements designated as B9 (GenBank accession no. U78639.1) to overcome the problem of detecting negative or low copy IS6110 containing strains of M. tuberculosis. The mPCR was evaluated using 346 clinical samples which included 283 sputum, 19 bronchial wash, 18 pleural fluid, 9 urine, 7 CSF, 6 pus, and 4 gastric lavage samples. Our results showed that the sensitivity (93.1 %) and specificity (89.6 %) of the mPCR system exceeds that of the conventional method of microscopy and culture. The mPCR assay provides an efficient strategy to detect and identify M. tuberculosis from clinical samples and enables prompt diagnosis when rapid identification of infecting mycobacteria is necessary.
The diagnosis of patients with fever of unknown origin (FUO) is often problematic because the range of possible differential diagnoses is broad. We report on a case in which a patient presented with FUO and was subsequently found to have both a collagen vascular disease and an intercurrent infection. Treatment for the collagen vascular disease with corticosteroids exacerbated the intercurrent infection. The problems in the diagnosis and management of such cases are discussed.
Mycobacterium tuberculosis (Mtb) is a pathogenic bacterium that causes tuberculosis (TB). This contagious disease remains a severe health problem in the world. The disease is transmitted via inhalation of airborne droplets carrying Mtb from TB patients. Early detection of the disease is vital to prevent transmission of the infection to people in close contact with the patients. To date, there is a need of a simple, rapid, sensitive and specific diagnostic test for TB. Previous studies showed the potential of Mtb 16 kDa antigen (Ag16) in TB diagnosis. In this study, lateral flow immunoassay, also called simple strip immunoassay or immunochromatographic test (ICT) for detection of Ag16 was developed (Mtb-strip) and assessed as a potential rapid TB diagnosis method. A monoclonal antibody against Ag16 was optimized as the capturing and detection antibody on the Mtb-strip. Parameters affecting the performance of the Mtb-strip were also optimized before a complete prototype was developed. Analytical sensitivity showed that Mtb-strip was capable to detect as low as 125 ng of purified Ag16. The analytical sensitivity of Mtb-strip suggests its potential usefulness in different clinical applications.
Because anti-tumor necrosis factor (anti-TNF) therapy has become increasingly popular in many Asian countries, the risk of developing active tuberculosis (TB) among anti-TNF users may raise serious health problems in this region. Thus, the Asian Organization for Crohn's and Colitis and the Asia Pacific Association of Gastroenterology have developed a set of consensus statements about risk assessment, detection and prevention of latent TB infection, and management of active TB infection in patients with inflammatory bowel disease (IBD) receiving anti-TNF treatment. Twenty-three consensus statements were initially drafted and then discussed by the committee members. The quality of evidence and the strength of recommendations were assessed by using the Grading of Recommendations Assessment, Development, and Evaluation methodology. Web-based consensus voting was performed by 211 IBD specialists from nine Asian countries concerning each statement. A consensus statement was accepted if at least 75% of the participants agreed. Part 2 of the statements comprised three parts: (3) management of latent TB in preparation for anti-TNF therapy, (4) monitoring during anti-TNF therapy, and (5) management of an active TB infection after anti-TNF therapy. These consensus statements will help clinicians optimize patient outcomes by reducing the morbidity and mortality related to TB infections in patients with IBD receiving anti-TNF treatment.
Because anti-tumor necrosis factor (anti-TNF) therapy has become increasingly popular in many Asian countries, the risk of developing active tuberculosis (TB) among anti-TNF users may raise serious health problems in this region. Thus, the Asian Organization for Crohn's and Colitis and the Asian Pacific Association of Gastroenterology have developed a set of consensus statements about risk assessment, detection, and prevention of latent TB infection and management of active TB infection in patients with inflammatory bowel disease (IBD) receiving anti-TNF treatment. Twenty-three consensus statements were initially drafted and then discussed by the committee members. The quality of evidence and the strength of recommendations were assessed by using the Grading of Recommendations Assessment, Development, and Evaluation methodology. Web-based consensus voting was performed by 211 IBD specialists from nine Asian countries concerning each statement. A consensus statement was accepted if at least 75% of the participants agreed. Part 1 of the statements comprised two parts: (i) risk of TB infection during anti-TNF therapy and (ii) screening for TB infection prior to commencing anti-TNF therapy. These consensus statements will help clinicians optimize patient outcomes by reducing the morbidity and mortality related to TB infections in patients with IBD receiving anti-TNF treatment.
A cross-sectional study was conducted from 10 January to 9 April 2012, to determine the seroprevalence of tuberculosis (TB) of all captive Asian elephants and their handlers in six locations in Peninsular Malaysia. In addition, trunk-wash samples were examined for tubercle bacillus by culture and polymerase chain reaction (PCR). For 63 elephants and 149 elephant handlers, TB seroprevalence was estimated at 20.4% and 24.8%, respectively. From 151 trunkwash samples, 24 acid-fast isolates were obtained, 23 of which were identified by hsp65-based sequencing as non-tuberculous mycobacteria. The Mycobacterium tuberculosis-specific PCR was positive in the trunk-wash samples from three elephants which were also seropositive. Conversely, the trunk wash from seven seropositive elephants were PCR negative. Hence, there was evidence of active and latent TB in the elephants and the high seroprevalence in the elephants and their handlers suggests frequent, close contact, two-way transmission between animals and humans within confined workplaces.
T cell receptor (TCR)-like antibodies, obtained with the use of phage display technology, sandwich the best of the both arms of the adaptive immune system. In this study, in vitro selections against the latency associated Mycobacterium tuberculosis (Mtb) heat shock protein 16 kDa antigen (16 kDa) presented by HLA-A*011 and HLA-A*24 were carried out with the use of a human domain phage antibody library. TCR-like domain antibodies (A11Ab and A24Ab) were successfully generated recognizing 16 kDa epitopes presented by HLA-A*011 and HLA-A*24 molecules respectively. Both antibodies were found to be functional in soluble form and exhibited strong binding capacity against its targets. The results obtained support the future evaluation of these ligands for the development of diagnostic and therapeutic tools for tuberculosis infection.
2020 will be marked in history for the dreadful implications of the COVID-19 pandemic that shook the world globally. The pandemic has reshaped the normality of life and affected mankind in the aspects of mental and physical health, financial, economy, growth, and development. The focus shift to COVID-19 has indirectly impacted an existing air-borne disease, Tuberculosis. In addition to the decrease in TB diagnosis, the emergence of the TB/COVID-19 syndemic and its serious implications (possible reactivation of latent TB post-COVID-19, aggravation of an existing active TB condition, or escalation of the severity of a COVID-19 during TB-COVID-19 coinfection), serve as primary reasons to equally prioritize TB. On a different note, the valuable lessons learnt for the COVID-19 pandemic provide useful knowledge for enhancing TB diagnostics and therapeutics. In this review, the crucial need to focus on TB amid the COVID-19 pandemic has been discussed. Besides, a general comparison between COVID-19 and TB in the aspects of pathogenesis, diagnostics, symptoms, and treatment options with importance given to antibody therapy were presented. Lastly, the lessons learnt from the COVID-19 pandemic and how it is applicable to enhance the antibody-based immunotherapy for TB have been presented.
In the Malaysian setting of multi-ethnicity and high BCG coverage, interpretation of Tuberculin Skin Testing (TST) may be difficult. Between January 2001 and December 2003, a retrospective study on all adult patients with documented TST results treated for tuberculosis (TB) in chest clinics of two government hospitals was conducted to determine the reliability of TST and factors affecting its interpretation. One hundred and three patients [mean age (SD): 43 (17); male: 67%] were eligible for data collection: 72% and 57% of patients had positive TST results based on cut-off points of 10mm and 15mm respectively. The only significant univariate association with TST results was the severity of co-morbidity. A patient with co-morbidity score of 3 defined as those with any cancer, end-stage renal or liver disease, or HIV disease, was more likely to have a negative TST results [10mm cut-off point: Odd Ratio (95% CI) 6.6 (1.82 to 24.35), p = 0.003; 15mm cut-off point: 4.8 (1.21 to 18.95), p = 0.012]. A TST reading of 10mm had a higher sensitivity than 15mm as the cut-off point in diagnosing TB infection. Considering all possible confounding factors like ethnicity, prior BCG vaccination and TB burden in the population, severity of co-morbidity remains strongly predictive of a negative TST. Caution should be exercised in interpreting TST in these patients.
Study site: Chest clinic, Hospital Seremban, Hospital Kuala Pilah, Negeri Sembilan, Malaysia
Technological advances in RNA biology greatly improved transcriptome profiling during the last two decades. Besides the discovery of many small RNAs (sRNA) that are involved in the physiological and pathophysiological regulation of various cellular circuits, it becomes evident that the corresponding RNA genes might also serve as potential biomarkers to monitor the progression of disease and treatment. sRNA gene candidate npcTB_6715 was previously identified via experimental RNomic (unpublished data), and we report its application as potential biomarker for the detection of Mycobacterium tuberculosis (MTB) in patient samples. For proof of principle, we developed a multiplex PCR assay and report its validation with 500 clinical cultures, positive for Mycobacteria. The analysis revealed 98.9% sensitivity, 96.1% specificity, positive and negative predictive values of 98.6% and 96.8%, respectively. These results underscore the diagnostic value of the sRNA gene as diagnostic marker for the specific detection of MTB in clinical samples. Its successful application and the general ease of PCR-based detection compared to standard bacterial culture techniques might be the first step towards 'point-of-care' diagnostics of Mycobacteria. To the best of our knowledge, this is the first time for the design of diagnostic applications based on sRNA genes, in Mycobacteria.
BACKGROUND: Health care workers are exposed to patients with tuberculosis and are at risk of nosocomial infection. The aim of this study was to determine the prevalence and factors associated with latent tuberculosis infection among health care workers in Malaysia and also to evaluate the agreement between Quantiferon TB Gold in tube test with Tuberculin Skin Test.
METHODS: A cross sectional study was conducted at four randomly selected hospitals in the Klang Valley from December 2008 to May 2009. Self administered questionnaire was used to obtain information on health care workers and possible risk factors. The response rate for this study was 90.8% with 954 respondents completed the questionnaire and were tested with Quantiferon TB Gold in tube for latent tuberculosis infection. Agreement between Quantiferon TB Gold in tube and Tuberculin Skin Test was assessed among 95 health care workers who consented to undergo both tests.
RESULTS: The overall prevalence of latent tuberculosis infection among health care workers was 10.6% (CI: 8.6%; 12.6%). Factors significantly associated with latent tuberculosis infection were aged 35 years and older [9.49 (CI: 2.22; 40.50)], history of living in the same house with close family members or friends who had active tuberculosis [8.69 (CI: 3.00; 25.18)], worked as a nurse [4.65 (CI: 1.10; 19.65)] and being male [3.70 (CI: 1.36; 10.02)]. Agreement between Quantiferon TB Gold in tube test and tuberculin skin test at cut-off points of 10 mm and 15 mm was 50.5% and 82.1% respectively. However, Kappa-agreement was poor for both cut-off points.
CONCLUSION: The prevalence of latent tuberculosis infection in Malaysia was relatively low for an intermediate TB burden country. We could not comment on the occupational risk of latent tuberculosis infection among health care worker compared to the general population as there were no prevalence data available for latent tuberculosis infection in the general population. Kappa agreement between Quantiferon TB gold in-tube and tuberculin skin test was poor.
A female patient presenting with post-prandial epigastric pain and weight loss was diagnosed to have oesophageal tuberculosis by endoscopic biopsy. She responded well to standard anti-tuberculosis treatment.
Tuberculosis (TB) is a highly infectious disease on the rise caused by the organism Mycobacterium tuberculosis and health care workers working in emergency departments, medical wards and autopsy rooms are in danger of contacting this disease. We present a case of a 42 year old man found dead under a pedestrian bridge with no medical history available. Post mortem computed tomography showed multiple cavities involving upper lobes of both lungs and areas of consolidation in both lung fields raising the suspicion of pulmonary tuberculosis. This was followed by a computed tomography guided lung biopsy and a limited conventional autopsy done in situ in a special high risk autopsy suite with appropriate ventilation. This case highlights the importance of cross sectional imaging which can be coupled with image guided biopsy in cases of infectious disease to reduce the risk of transmission to health care workers.
Rapid and highly accurate diagnostic tools are critically needed to diagnose Mycobacterium tuberculosis and rifampicin resistance in AFB smear-negative samples. In this study, we evaluated the diagnostic performance of Xpert MTB/RIF Ultra (Ultra) as a rapid test to diagnose tuberculosis in smear-negative cases in Malaysia. A retrospective study of 1960 smear-negative pulmonary and extrapulmonary samples obtained from patients was conducted. Culture was used as the reference standard for the study. The overall sensitivity and specificity of Ultra on the tested samples were 88.7 % and 77.2 %, respectively, while the PPV was 32.3 % and the NPV was 98.2 %. Ultra showed slightly higher sensitivity in pulmonary (89.9 %) compared to extrapulmonary samples (86.1 %). The overall accuracy of Ultra was 78.5 % (kappa=0.37; 95 %CI: 0.32,0.42). Ultra showed good diagnostic accuracy for detecting MTB and rifampicin resistance in various AFB smear-negative samples. Ultra also had excellent capability in rifampicin resistance detection.
BACKGROUND: Serial testing for tuberculosis (TB) exposure has been advocated among health care workers (HCWs) at risk of nosocomial infection.
OBJECTIVE: To determine the incidence and factors associated with TB infection among selected HCWs in Malaysia and to determine interferon-gamma response in serial testing.
DESIGN: A cohort of 769 HCWs were retested after 1 year using QuantiFERON®-TB Gold In-Tube. Incidence of TB infection was determined among HCWs who previously tested negative. Conversion and reversion rates using several definitions were explored.
RESULTS: Incidence of TB infection was 9.9 per 100 workers per year (95%CI 7.9-12.3). Working in the Emergency Department (ED; RR 2.18, 95%CI 1.07-4.43) was significantly associated with risk of TB infection. Reversion and conversion occurred frequently, with 46.7% reversion among HCWs with baseline interferon-gamma (IFN-γ) levels of 0.35-0.70 international units (IU)/ml, and 23.8% conversion among HCWs with baseline IFN-γ levels of 0.20-0.34 IU/ml.
CONCLUSIONS: TB infection control measures need to be strengthened, particularly in the ED, as the incidence of TB was high. Conversion and reversion rates in serial testing were high, and further studies are needed to facilitate its interpretation.
This study determined the costs associated with tuberculosis (TB) diagnosis and treatment for the public health services and patients in Sana'a, Yemen. Data were collected prospectively from 320 pulmonary and extrapulmonary TB patients (160 each) who were followed until completion of treatment. Direct medical and nonmedical costs and indirect costs were calculated. The proportionate cost to the patients for pulmonary TB and extrapulmonary TB was 76.1% arid 89.4% respectively of the total for treatment. The mean cost to patients for pulmonary and extrapulmonary TB treatment was US$ 108.4 and US$ 328.0 respectively. The mean cost per patient to the health services for pulmonary and extrapulmonary TB treatment was US$ 34.0 and US$ 38.8 respectively. For pulmonary and extrapulmonary TB, drug treatment represented 59.3% and 77.9% respectively of the total cost to the health services. The greatest proportionate cost to patients for pulmonary TB treatment was time away from work (67.5% of the total cost), and for extrapulmonary TB was laboratory and X-ray costs (55.5%) followed by transportation (28.6%).
The aim of the present study is rapid detection of tuberculosis from pleural effusion of suspected patients. Molecular technique Nested Polymerase Chain Reaction (PCR) was used for the purpose. A total of 67 pleural fluid collected at Hospital University Kebangsaan Malaysia during May 2005 to October 2006 were sent to Microbiology Laboratory enrolled in the study. Detection rate of Mycobacterium tuberculosis in pleural effusion was 0% by acid-fast bacilli (AFB) staining and 1.5% by culture on Lowenstein-Jensen medium. Mycobacterium tuberculosis was detected by PCR in 9% of the cases. PCR of pleural fluid had 19% sensitivity and 96% specificity, compared to AFB staining (0% sensitivity and 100% specificity) and culture (4% sensitivity and 100% specificity). PCR also has 67% Positive Predictive Value (PPV) and 72% Negative Predictive Value (NPV) in detecting Mycobacterium tuberculosis. Culture ofpleural fluid has 100% PPV and 71% NPV while AFB staining has 0% PPV and 31% NPV. This preliminary study showed that PCR is a rapid method for detection of Mycobacterium tuberculosis in pleural fluid but its sensitivity is not up the marked.
Fasciolopsiasis is a disease caused by the largest intestinal fluke, Fasciolopsis buski. The disease is endemic in the Far East and Southeast Asia. Human acquires the infection after eating raw freshwater plants contaminated with the infective metacercariae. There has been no report of fasciolopsiasis either in man or in animal in Malaysia. We are reporting the first case of fasciolopsiasis in Malaysia in a 39-year-old female farmer, a native of Sabah (East Malaysia). This patient complained of cough and fever for a duration of two weeks, associated with loss of appetite and loss of weight. She had no history of traveling overseas. Physical examination showed pallor, multiple cervical and inguinal lymph nodes and hepatosplenomegaly. Laboratory investigations showed that she had iron deficiency anemia. There was leukocytosis and a raised ESR. Lymph node biopsy revealed a caseating granuloma. Stool examination was positive for the eggs of Fasciolopsis buski. The eggs measure 140 x 72.5 microm and are operculated. In this case, the patient did not present with symptoms suggestive of any intestinal parasitic infections. Detection of Fasciolopsis buski eggs in the stool was an incidental finding. She was diagnosed as a case of disseminated tuberculosis with fasciolopsiasis and was treated with antituberculosis drugs and praziquantel, respectively.
This study was carried out to compare the performance of BACTEC MGIT 960 with the BACTEC 460 TB for growth and detection of Mycobacteria from human clinical specimens. The BACTEC MGIT 960 instrument is a fully automated system that utilizes MGIT tubes containing an oxygen sensor embedded in silicon at the bottom and filled with 7 mL of modified Middlebrook 7H9 broth. Identical samples were inoculated into the two automated systems and incubated for six weeks. Over a period of three months, 279 specimens were decontaminated and processed according to the standard CDC NALC/NaOH method, using the commercial MycoPrep kit. Forty-two specimens (15%) yielded Mycobacterium tuberculosis; 37 (88%) were detected by the fluorescent BACTEC MGIT 960 and 35 (83%) detected by the radiometric BACTEC 460 TB. Fifteen specimens (5%) yielded Mycobacterium Other Than Tuberculosis (MOTT); 10 (66%) were detected by BACTEC MGIT 960 and 11 (73%) detected by BACTEC 460 TB. The average time to detection and contamination rates and the average time to obtain results of antimicrobial susceptibility tests between the two systems were compared. The performance of the BACTEC MGIT 960 was comparable to the BACTEC 460 TB system which has been the "Gold Standard" for automated detection of TB. The former was more rapid, as sensitive and less labour intensive than the BACTEC 460. Our data demonstrates that the BACTEC MGIT 960 system is an accurate, automated and a non-radioactive alternative to the BACTEC 460 TB for the culture and susceptibility testing of M. tuberculosis.