Researches
Serological diagnosis and monitoring of Mycobacterium avium complex lung diseases by Enzyme Immunoassay of IgA antibodies agains
Date: 2020-04-16
Author: Dr. TAM Wai On
Summary: Introduction: There is an increasing trend worldwide in the incidence of Mycobacterium avium complex pulmonary diseases (MAC-PD) and the diagnosis is sometimes complicated. Recently, an enzyme immunoassay (EIA) kit that detects serum IgA antibody against MAC-specific glycopeptidolipid (GPL) core antigen had been developed and found to be useful in discriminating MAC-PD from other lung diseases. The antibody was subsequently also found to be elevated in patients suffering Mycobacterium abscessus pulmonary diseases (MAB-PD). This study is to evaluate this EIA kit in the serological diagnosis of MAC-PD in Hong Kong Chinese patients. Methods: The study was conducted in Grantham Hospital, Hong Kong between July 2017 to July 2018. Assay of the IgA antibody level using the EIA kit was done on blood samples collected from patients suffering from MAC-PD, MAB-PD, pulmonary tuberculosis and other lung diseases. Results: There were 100 subjects recruited into the study, among which 11 were excluded. By the cut-off value set by the manufacturer, the sensitivity and specificity for diagnosis were 73.7% and 77.6% for MAC-PD; 50% and 77.6% for MAB-PD. By receiver operating characteristic curves analysis, the best cut-off for MAC-PD was 1.771 U/mL and for MAB-PD was 0.172 U/mL. Using this best cut-off, the sensitivity and specificity was 68.4% and 86.2% for MAC-PD; 66.7% and 72.4% for MAB-PD respectively. Conclusions: This study showed that measurement of IgA antibodies against MAC-specific glycopeptidolipid core antigen may be useful in the diagnosis of MAC-PD among Hong Kong Chinese patients and helped to differentiate MAB-PD from other lung diseases.
Direct Detection of Pyrazinamide Resistance in Mycobacterium tuberculosis by Use of pncA PCR Sequencing
Date: 2019-07-31
Author: Dr. Wing-Cheong Yam
Summary: An in-house-developed pncA sequencing assay for analysis of pyrazinamide (PZA) resistance was evaluated using 162 archived Mycobacterium tuberculosis complex (MTBC) isolates with phenotypic PZA susceptibility profiles that were well defined by analysis of Bactec MGIT 960 PZA kit and PZase activity data. Preliminary results showed 100% concordance between pncA sequencing and phenotypic PZA drug susceptibility test (DST) results among archived isolates. Also, 637 respiratory specimens were prospectively collected, and 158 were reported as MTBC positive by the Abbott Realtime MTB assay (96.3% sensitivity [95% confidence interval {CI}: 92.2% to 98.7%]; 100% specificity [95% CI: 99.2% to 100.0%]). Genotypic and phenotypic PZA resistance profiles of these 158 MTBC-positive specimens were analyzed by pncA sequencing and Bactec MGIT 960 PZA kit, respectively. For analysis of PZA resistance, pncA sequencing detected pncA mutations in 5/5 (100%) phenotypic PZAresistant respiratory specimens within 4 working days. No pncA mutations were detected among PZA-susceptible specimens. Combining archived isolates with prospective specimens, 27 were identified as phenotypic PZA resistant with pncA mutation. Among these 27 samples, 6/27 (22.2%) phenotypic PZA-resistant strains carried novel pncA mutations without rpsA and panD mutations. These included 5 with mutations (a deletion [Del] at 383T [Del383T], Del 380 to 390, insertion of A [A Ins] at position 127, A Ins at position 407, and G Ins at position 508) in pncA structural genes and 1 with a mutation (T-12C) at the pncA promoter region. All six of these strains had no or reduced PZase activities, indicating that the novel mutations might confer PZA resistance. Additionally, 25/27 phenotypic PZA-resistant strains were confirmed multidrug-resistant tuberculosis (MDR-TB) strains. As PZA is commonly used in MDR-TB treatment regimens, direct pncA sequencing will rapidly detect PZA resistance and facilitate judicious use of PZA in treating PZA-susceptible MDR-TB.
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Appendix 1
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Scientific Research Fund on Lung Health
Date: 2018-12-19
Author: Hong Kong Tuberculosis, Chest an
Summary: Lung is the internal organ most vulnerable to infection with frequent injury from the external environmental causes. Death rate in Hong Kong due to lung problems remains at high level among the elderly. In this respect, the Association set up a Scientific Committee on Lung Health in 2013 aiming at enhancing the effectiveness of treating lung-related diseases through the advancement of research work. It is a platform for professionals to gather to facilitate and co-ordinate scientific researches among organisations and institutions. To encourage more large-scale and long term research work, your generous donation is much appreciated. It is our promise that your donation will be solely for research and all administration fees will be absorbed by the Association separately. We are more committed and energised than ever to make a contribution to the future of lung health for years to come. Your support to the Scientific Research Fund on Lung Health will eventually improve the overall lung health in Hong Kong. Thank you in advance for your kind generosity and unwavering support.
Completion Form - Covering for the Final Report
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Interim Report
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Application Form
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Application Guidelines
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11 - 中国农村小区的结核潜伏感染流行病学调查和干预研究
Date: 2017-11-02
10 - 香港结核病预防及控制 - 监督治疗
Date: 2017-11-02
9 - 澳门地区结核病分子流行病学分析
Date: 2017-11-02
8 - 结核分枝杆菌基因分形技术的应用
Date: 2017-11-02
7 - 结核分枝杆菌耐药体外遗传进化
Date: 2017-11-02
6 - 结核性腰大肌脓伤
Date: 2017-11-02
5 - 上海市结核病管理信息系统与疫情分析
Date: 2017-11-02
2 - 结核病 MS管理信息系统介绍
Date: 2017-11-02
Application on GeneXpert on bronchoscopic samples in the clinical management of patients suspicious of Tuberculosis
Date: 2017-11-13
Author: Dr. TO Kin Wang
Summary: Background: There is limited experience on clinical use of GeneXpert on bronchoalveolar lavage (BAL) fluid samples obtained from patients clinically suspected of pulmonary tuberculosis (TB) in intermediate burden settings. Methods: sputum acid-fast-bacilli (AFB) smear negative patients were offered bronchoscopy. BAL fluid was collected for AFB smear, TB culture, Cobas Taqman TB polymerase chain reaction (PCR) and for GeneXpert. Cases were diagnosed as TB if any one of the tests was positive. Results: From December 2014 to February 2017, 227 samples were collected. Patients’ mean (SD) age was 60.7 (15) years, 143 patients were males and 84 were females. Cough and haemoptysis were the presenting symptoms in 70% and 37.4% respectively. Apical shadows in chest X-ray (CXR) and apical cavitations in computed tomography (CT) were more common in GeneXpert positive cases (p=0.01 and 0.02 respectively). Sensitivities and specificity of GeneXpert was 80% and 98% respectively. The positive predictive value and negative predictive value was 92.3 and 95.1% respectively. There were 9 false negative GeneXpert samples (8 were Cobas Taqman TB PCR negative): 6 were diagnosed by BAL culture, 2 by biopsy and one by Cobas Taqman TB PCR. There were 3 false positive cases with negative culture, 2 were put on empirical treatment with favorable clinical responses, while one defaulted followed up. Conclusion: GeneXpert in BAL samples has high specificity and similar performance as Cobas Taqman PCR to rule in TB for initiating early treatment in clinical suspicious cases. However, it cannot replace other investigations as the only test for diagnosing pulmonary TB.
1 - 香港特别行政区结核杆菌 / 艾滋病病毒 (TB/HIV) / 双重感染死亡个案分析
Date: 2017-11-02
Sinew Acupuncture for de Quervain's Tenosynovitis: a randomized subject- and assessor-blinded controlled trial
Date: 2017-03-01
Author: Aberdeen Clinic
Summary: The project is sponsored by the Hospital Authority and supervised by the University of Hong Kong. It is expected to be completed by mid 2019.
Sinew Acupuncture for Knee Osteoarthritis (KOA): a randomized, sham controlled, patient and assessor blinded, pilot trial
Date: 2017-05-01
Author: Tang Shiu Kin Clinic
Summary: The project is sponsored by the Hospital Authority and supervised by the University of Hong Kong. It is expected to be completed by late 2018.
Optimizing MGIT pyrazinamide susceptibility testing using a reduced inoculum
Date: 2016-07-31
Author: Dr. YAM Wing Cheong
Summary: Pyrazinamide (PZA) is considered an essential component of first-line TB therapy, it is important that laboratories should adopt a successful algorithm to provide rapid and accurate susceptibility results for PZA. In this study, testing 160 M. tuberculosis isolates indicated no significant difference between standard and reduced inoculums for MGIT960 PZA susceptibility test (p >0.05). The failure rate was higher for reduced inoculums (6.9%) than the standard inoculums (1.8%). Further investigation on isolates using PCR-sequencing indicated all PZA resistant strains exhibited pncA mutations (known or novel) with the most common G162D genotype as described previously in Hong Kong. The PCR-sequencing is highly sensitive to detect all pncA mutations among our PZA resistant isolates collected over 10 years (2003-2013) in Hong Kong. Another 20 confirmed PZA susceptible isolates exhibited pncA wild types, indicating PZA resistance is mainly associated with pncA mutations in our locality. This is further verified by pyrazinamidase (PZase) activity among our PZA susceptible and resistant isolates. As M. tuberculosis isolates from all Hospital Authority Microbiology Laboratories are centralized in the TB reference Laboratory (PHLSB) for DST using MGIT960 system, we propose retesting all PZA-resistant isolates to provide accurate and reliable susceptibility results. Any M. tuberculosis clinical isolate reported as PZA resistant by the MGIT960 should be confirmed by PZase assay and pncA gene mutation analysis using PCR-sequencing.