Serological diagnosis and monitoring of Mycobacterium avium complex lung diseases by Enzyme Immunoassay of IgA antibodies agains
日期: 2020-04-16
作者: Dr. TAM Wai On
摘要: 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
日期: 2019-07-31
作者: Dr. Wing-Cheong Yam
摘要: 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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日期: 2018-12-19
作者: 香港防痨心脏及胸病协会
摘要: 肺部是最容易受到外部环境伤害的内部器官。在香港,长者因肺部问题导致死亡的百分比一直高企。有见及此,防痨会于2013年成立了「科硏及胸肺健康委员会」,以聚集本地专业人士,鼓励、协助并协调香港各组织和机构的科学研究,从而提高治疗肺部疾病的疗效。 为了鼓励更多大规模和持续性的研究工作,我们需要您的慷慨捐助。我们承诺您的捐款将全数用于研究工作,所有行政管理费用均由防痨会承担。 我们会一如以往,继续努力服务市民。我们真诚希望您能支持胸肺科研基金,以提升香港有关肺部健康硏究的领域。
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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
日期: 2017-11-02
10 - 香港结核病预防及控制 - 监督治疗
日期: 2017-11-02
9 - 澳门地区结核病分子流行病学分析
日期: 2017-11-02
8 - 结核分枝杆菌基因分形技术的应用
日期: 2017-11-02
7 - 结核分枝杆菌耐药体外遗传进化
日期: 2017-11-02
6 - 结核性腰大肌脓伤
日期: 2017-11-02
5 - 上海市结核病管理信息系统与疫情分析
日期: 2017-11-02
2 - 结核病 MS管理信息系统介绍
日期: 2017-11-02
Application on GeneXpert on bronchoscopic samples in the clinical management of patients suspicious of Tuberculosis
日期: 2017-11-13
作者: Dr. TO Kin Wang
摘要: 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
日期: 2017-11-02
Sinew Acupuncture for de Quervain's Tenosynovitis: a randomized subject- and assessor-blinded controlled trial
日期: 2017-03-01
作者: Aberdeen Clinic
摘要: 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
日期: 2017-05-01
作者: Research Team of Chinese Medicin
摘要: 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
日期: 2016-07-31
作者: Dr. YAM Wing Cheong
摘要: Among the 150 culture isolates, 11 isolates failed in the MGIT 960 PZA susceptibility test due to under inoculums size (3 isolates for both standard and reduced inoculums; 8 isolates for reduced inoculums only). The failure rate for standard and reduced inoculums was 1.8% (3/171) and 6.4% (11/171) respectively. Only 139 isolates were eligible for further study and analysis. Another 21 archived PZA resistant strains collected between 2003-2013 were also included for comparative study. However, one strain was later confirmed to be PZA susceptible that 140 PZA susceptible and 20 PZA resistant strains were used for the McNemar’s analysis, indicating there is no significant difference between standard and reduced inoculums for MGIT960 PZA susceptibility test (p = 0.6171; Odd Ratio = 1; 95% CI: 0.072 – 13.796). The 20 PZA resistant archived strains collected between 2003-2013 were further characterized by MGIT960 PZA (standard and reduced inoculums) test, PZase activity and DNA sequencing to identify pncA mutations. The most common PZA resistant mutations at pncA were G162D and I90S. Novel mutations including insertions and deletions were also detected among PZA resistant strains. PZase activity were negative for all PZA resistant strains while 20 randomly selected PZA susceptible strains were positive to PZase activity with no mutations in the pncA gene. One strain (WC036) reported as PZA susceptible by TB Reference laboratory (PHLSB) was confirmed resistant to PZA by MGIT960 (both standard and reduced inoculum) with pncA mutations and negative for PZase activity. Another strain (WC205) reported as susceptible to all first line drugs but resistant to PZA was also confirmed susceptible to PZA by MGIT960 (both standard and reduced inoculum) with wild type pncA and positive for PZase activity. 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 for standard and reduced inoculums was 1.8% and 6.4% respectively. The 1 false susceptible and 1 false resistant isolates reported by TB reference Laboratory (PHLSB) was probably accounted by the drug susceptibility test other than MGIT960. Since 2014, PHLSB has adopted the MGIT960 system with standard inoculums size for routine service to all Hospital Authority Hospitals in Hong Kong. For routine PZA MGIT 960 susceptibility testing using standard inoculums, clinical isolates reported as resistant to PZA should be confirmed by PZase activity and pncA gene mutation analysis using PCR-sequencing.