Comparison of a whole-blood interferon gamma assay with tuberculin skin testing for detecting latent Mycobacterium tuberculosis infection

CONTEXT: Identifying persons with latent tuberculosis infection (LTBI) is crucial to the goal of TB elimination. A whole-blood interferon gamma (IFN-gamma) assay, the QuantiFERON-TB test, is a promising in vitro diagnostic test for LTBI that has potential advantages over the tuberculin skin test (TST). OBJECTIVES: To compare the IFN-gamma assay with the TST and to identify factors associated with discordance between the tests. DESIGN AND SETTING: Prospective comparison study conducted at 5 university-affiliated sites in the United States between March 1, 1998 and June 30, 1999. PARTICIPANTS: A total of 1226 adults (mean age, 39 years) with varying risks of Mycobacterium tuberculosis infection or documented or suspected active TB, all of whom underwent both the IFN-gamma assay and the TST. MAIN OUTCOME MEASURE: Level of agreement between the IFN-gamma assay and the TST. RESULTS: Three hundred ninety participants (31.8%) had a positive TST result and 349 (28.5%) had a positive IFN-gamma assay result. Overall agreement between the IFN-gamma assay and the TST was 83.1% (kappa = 0.60). Multivariate analysis revealed that the odds of having a positive TST result but negative IFN-gamma assay result were 7 times higher for BCG-vaccinated persons compared with unvaccinated persons. The IFN-gamma assay provided evidence that among unvaccinated persons with a positive TST result but negative IFN-gamma assay result, 21.2% were responding to mycobacteria other than M tuberculosis. CONCLUSIONS: For all study participants, as well as for those being screened for LTBI, the IFN-gamma assay was comparable with the TST in its ability to detect LTBI, was less affected by BCG vaccination, discriminated responses due to nontuberculous mycobacteria, and avoided variability and subjectivity associated with placing and reading the TST.     

Discrepancy between the tuberculin skin test and the whole-blood interferon gamma assay for the diagnosis of latent tuberculosis infection in an intermediate tuberculosis-burden country

Context  A recently developed whole-blood interferon (IFN-) assay based on stimulation with the Mycobacterium tuberculosis–specific antigens early secreted antigenic target 6 and culture filtrate protein 10 shows promise for the diagnosis of latent tuberculosis (TB) infection. Objective  To compare the tuberculin skin test (TST) and the whole-blood IFN- assay in the diagnosis of latent TB infection according to the intensity of exposure. Design and Setting  A prospective comparison between the whole-blood IFN- assay and the TST using a 2-TU dose of purified protein derivative RT23 in a population with intermediate TB burden was conducted sequentially between February 1, 2004, and February 28, 2005, in a Korean tertiary referral hospital. Participants  Of 273 participants, 220 (95.7%) had received BCG vaccine. Participants were grouped according to their risk of infection: group 1, no identifiable risk of M tuberculosis infection (n = 99); group 2, recent casual contacts (n = 72); group 3, recent close contacts (n = 48); group 4, bacteriologically or pathologically confirmed TB patients (n = 54). Main Outcome Measures  Levels of agreement between the TST and the IFN- assay and the likelihood of infection in the various groups. Results  For the TST with a 10-mm induration cutoff, the positive response rate in group 1 was 51%; group 2, 60%; group 3, 71%, and group 4, 78%. For the IFN- assay, the positive response rate in group 1 was 4%; group 2, 10%; group 3, 44%; and group 4, 81%. The overall agreement between the TST and the IFN- assay in healthy volunteers was = 0.16. The odds of a positive test result per unit increase in exposure across the 4 groups increased by a factor of 5.31 (95% confidence interval [CI], 3.62-7.79) for the IFN- assay and by a factor of 1.52 (95% CI, 1.20-1.91) for the TST (P<.001). Using a 15-mm induration cutoff for the TST did not make a substantial difference to the test results. Conclusion  The IFN- assay is a better indicator of the risk of M tuberculosis infection than TST in a BCG-vaccinated population.      

γ-干扰素释放试验在潜伏结核感染治疗效果评价中的应用价值

目的:探讨γ-干扰素释放试验(IGRA)在潜伏结核感染(LTBI)治疗效果评价中的应用价值。方法:采用回顾性分析,选取2020年1-5月浙江省湖州市中心医院收治的结核感染患者作为研究对象,随机抽取LTBI 30例作为试验组,进行预防性抗结核治疗(TPT)。随机抽取肺结核患者30例作为对照组,进行规范抗结核治疗。比较两组治疗开始时、治疗后3个月的IGRA值。结果:治疗开始时,试验组的IGRA值为(329.53±255.34)pg/ml,对照组的IGRA值为(451.84±260.59)pg/ml,两组的IGRA值比较,差异无统计学意义(P>0.05)。治疗3个月时,试验组的IGRA值中位数为[13.50(10.00,70.00)]pg/ml,对照组的IGRA值中位数为[52.15(12.75,110.35)]pg/ml,试验组的IGRA值低于对照组,差异有统计学意义(P<0.05)。试验组的IGRA值阴转15例(50.0%),对照组IGRA值阴转8例(26.7%),两组的IGRA阴转情况比较,差异无统计学意义(P>0.05)。组内比较,对照组和试验组治疗后的IGRA值均较前下降,差异有统计学意义(Z=5.872;Z=5.360,P<0.001)。结论:在LTBI中,IGRA值变化的程度优于普通肺结核病人。IGRA的动态变化可为LTBI治疗效果评价提供依据。     

γ-干扰素释放试验与结核分枝杆菌耐药基因特征研究

目的 分析γ-干扰素释放试验（interferon gamma release assay, IGRA）与结核分枝杆菌耐药基因的特征性,为临床诊治耐多药结核提供参考依据。方法 选取2019年1月1日-2020年1月1日在海南医学院第二附属医院住院的肺结核49例（肺结核组）和肺炎51例（肺炎组）为研究对象,另选取同期进行健康体检者40例为对照组,采用γ-干扰素释放试验检测γ-干扰素水平,同时采用DNA微阵列芯片法对肺结核组进行耐药基因检测,所得数据采用SPSS19.0软件进行统计学分析。结果 肺结核组、肺炎组和对照组IGRA阳性率分别为57.1%（28/49）、29.4%（15/51）和2.5%（1/40）,3组差异有统计学意义（P<0.01）。rpoB基因检出率和突变率分别为34.7%（17/49）和35.3%（6/17）,常见的突变位点分别为531、513、526、511,rpoB基因突变类型分别为531位点（C->T）、513位点（C->A）、526位点（A->T）及511位点（T->C）;katG315基因检出率和突变率分别为34.7%（17/49）和17.6%（3/17）,突变类型为katG315位点AGC->ACC;检出和未检出rpoB基因的IGRA阳性率分别为82.4%（14/17）和43.8%（14/32）,差异有统计学意义（P<0.01）。检出和未检出katG315基因的IGRA阳性率分别为82.4%（14/17）和46.8%（15/32）,差异有统计学意义（P<0.05）。结论 rpoB突变位点呈多样性,而katG315呈单一性;联合IGRA和基因的检测结果对临床结核的诊断和治疗更有意义。     

结核免疫斑点试验与结核菌素试验在活动性结核病诊断中的优越性对比

目的：比较结核免疫斑点试验( enzyme-linked immunospot assay for inferferon-γ,T-SPOT. TB)与结核菌素试验( purified protein derivative,PPD)在活动性结核病诊断中的优越性。方法前瞻性研究2013年4月至2014年5月本院收治的疑似活动性结核病患者124例,随访至少6个月,证实结核患者43例,排除结核病72例,剔除9例。所有患者均行T-SPOT. TB与PPD检测,比较两组检验方法的主要诊断实验指标。结果 T-SPOT. TB和PPD的敏感度分别为90.70%、32.56%;特异度分别为83.33%、79.17%。检测的符合率分别为86.09%、61.74%,阳性预测值分别为76.47%、48.28%,阴性预测值分别为93.75%、66.28%;阳性似然比分别为5.32、1.56,阴性似然比分别为0.096、0.852。结论 T-SPOT. TB在活动性结核病中的诊断价值明显优于PPD,但不能完全取代PPD,临床上有必要进行联合开展。     

儿童隐性结核感染和结核纯蛋白衍生物的判断

由于各国政府的缺乏认识和不重视、移民和难民的增加、HIV感染和艾滋病的流行以及多重耐药结核病病例的增加,全球结核病患者人数较前增加。据世界卫生组织(WHO)统计,世界人口的1／3都染有结核,每年有8百万人因感染结核而发病,其中每年有超过25万名儿童死于结核病。由于儿童家庭接触密切,特别容易感染结核,这些已感染而未经诊治的儿童即隐性结核感染者,将成为未来成人结核的巨大隐患。为了实现控制和消灭结核病的目标,必须消减现有已感染者并不再产生新的感染者。因此,儿童隐性结核感染的诊断和治疗是儿科医生不可忽视的问题。     

Outbreak control of hospital acquired varicella infection amongst health care workers in a tertiary care hospital

BackgroundAdult and immunocompromised patients suffering from varicella (chicken pox) are potential source of infection to healthcare workers. An outbreak of varicella among healthcare workers in a tertiary care centre was investigated, and preventive measures were implemented.MethodsCases of chicken pox between 05 Feb 2017 and 11 Feb 2017 in a tertiary healthcare establishment were investigated. An epidemiological investigation by developing case definitions, spot map and contact tracing was conducted. Eight cases were identified among healthcare workers. Suitable preventive measures including identification of susceptible contacts and vaccination of susceptible ones with two doses of varicella vaccine was undertaken.ResultsIndex case was a 21-year-old nurse who was exposed to a 34-year-old male patient transferred from a secondary care hospital on 24 Jan 2017 as a case of acute liver failure and coagulopathy. Primary case was later diagnosed as case of varicella based on serological and clinical evidence. Among a total of 8 cases identified in the outbreak, the cases occurred among healthcare workers of secondary care centre, healthcare workers managing the primary case in the intensive care unit and who conducted the autopsy. A total of 181 contacts were identified in the epidemiological investigation, and 54 were susceptible to chicken pox. Two-dose immunization with varicella vaccination of susceptible ones was found to be effective in preventing further cases.ConclusionTwo-dose vaccination of healthcare workers with varicella vaccine is an effective strategy to prevent nosocomial varicella among healthcare workers.     

Performance of the microscopic observation drug susceptibility assay in pyrazinamide susceptibility testing for Mycobacterium tuberculosis

Background Drug susceptibility assay is very important in tuberculosis therapy. Pyrazinamide is a first line antituberculosis drug and diagnosis of its resistance in Mycobacterium tuberculosis （M. tuberculosis） is difficult and time consuming by conventional methods. In this study, we aimed to evaluate the performance of the microscopic observation drug susceptibility （MODS） assay in the detection of pyrazinamide resistance in M. tuberculosis relative to the conventional Wayne assay and Lowenstein-Jensen （L J） proportion method. Methods M. tuberculosis clinical isolates （n=132） were tested by the MODS and the Wayne assay： the results were compared with those obtained by the LJ proportion method. Mutations in the gene were identified by direct sequencing of the pncA genes of all isolates in which pyrazinamide resistance was detected by any of the three methods. Results Compared to the LJ results, the sensitivity and specificity of the MODS assay were 97.8% and 96.5% respectively; the sensitivity and specificity of the Wayne assay were 87.0% and 97.7% respectively. Mutations in the pncA gene were found in 41 of 46 strains that were pyrazinamide resistant （3 tests）, in 1 of the 4 strains （LJ only）, in 42 of 48 strains （at least I test）, but no mutations in 1 strain sensitive according to the MODS assay only. The MODS assay, Wayne assay and LJ proportion method provided results in a median time of 6, 7 and 26 days respectively. Conclusions MODS assay offers a rapid, simple and reliable method for the detection of pyrazinamide resistance in M. tuberculosis and is an optimal alternative method in resource limited countries.     

湖北省防疫人员患肺结核病调查

目的 了解湖北省密切接触结核病患者的防疫人员结核病发生情况，及其与工作环境、工种、工作年限、发病年龄、治愈情况、并存病及毒副作用的关系。方法对湖北省1992～2002年的结核病防疫人员的结核病患病情况进行调查、分析。结果在调查的6658例结核病防疫人员中，271人患肺结核，患病率为4．1％，其中涂片阳性者156人，涂阳患病率为2．4％，在涂阳病例中，新发涂阳占88．56％。结论 改善结核病防疫医师工作环境，提高防疫人员的自我保护意识是降低防疫人员结核病患病率的关系。     

小鼠结核分枝杆菌耐药模型的建立与评价

目的建立小鼠结核分枝杆菌耐利福平株静脉感染小鼠模型。方法 30只BALB/c雌性小鼠经尾静脉感染结核分枝杆菌耐利福平株每只106CFU,观察小鼠一般状况,并分别在感染后6周、10周、14周处死小鼠,进行脾、肺组织病理切片、抗酸染色、计脏器荷菌数。结果感染后小鼠体重呈逐渐上升趋势,脏器病理变化随时间推移由急性炎症逐渐转为慢性炎症反应,抗酸染色均为阳性,脏器荷菌数与感染剂量相对应,并至少可持续14周。结论成功建立了小鼠结核分枝杆菌耐利福平株静脉感染动物模型,为其进一步用于结核病防治研究奠定了一定的基础。     

Longitudinal observation of an interferon gamma-released assay (T-SPOT.TB) for Mycobacterium tuberculosis infection in AIDS patients on highly active antiretroviral therapy

Background T-SPOT.TB is a novel test for tuberculosis infection with higher sensitivity and specificity than the traditional tuberculin skin test （TST）. However, there are no longitudinal data in the literature evaluating T-SPOT.TB for Mycobacterium tuberculosis in patients with acquired immune deficiency syndrome （AIDS） on highly active antiretroviral therapy （HAART）. The objective of this study was to assess the value of T-SPOT.TB longitudinally in AIDS patients on HAART without prophylaxis for tuberculosis.Methods A prospective observational study was conducted in 50 AIDS patients on HAART. None of the subjects had evidence of active tuberculosis. T-SPOT.TB, a T-cell-based interferon y released assay, was performed at the onset of the study and repeated 24 months thereafter. Subjects were evaluated every 6 months during the 36-month follow-up. Results Twenty-one （42%） AIDS patients on HAART tested positive by T-SPOT.TB （95% Cl 28.3%-55.7%）. The pooled spot-forming cells of early secretory antigenic target-6 （ESAT-6） and culture filtrate protein-10 （CFP-10） peptides were 68/million peripheral blood mononuclear cell （PBMC） （interquartile range 44-220）. The average number of CD4 cells in subjects was （305±152） cells/Ml and there was no significant difference in T-SPOT.TB response rates between subjects with CD4 cell counts 〈200 cells/ul （7/15 （46.7%）, 95% C/21.5%-71.9%） and those with CD4 cell counts≥200 cells/ul （14/35 （40.0%）, 95% Cl 23.8%-56.2%, P=0.662）. In the 32 subjects who completed the 24-month follow-up, 10 underwent T-SPOT.TB reversion, one had T-SPOT.TB conversion, six remained positive and 15 remained negative. None of them advanced to active tuberculosis during the 36-month follow-up.Conclusion The inactive status of tuberculosis infection may be maintained for a long period in AIDS patients on HAART.     

痰液miR-155检测作为诊断结核分枝杆菌感染标志物的研究

目的 分析结核分枝杆菌H37Rv感染诱导宿主巨噬细胞表达miRNA的变化,进而验证差异miRNA对结核分枝杆菌感染的临床诊断意义。方法 使用H37Rv菌株感染人巨噬细胞系THP-1细胞后,收集12 h、24 h和48 h细胞并提取总RNA,进行miRNA微阵列芯片分析;再将临床分离的120株不同个体来源的结核分枝杆菌菌株与THP-1细胞共培养,使用实时定量PCR (real time-PCR, rt-PCR)验证差异miRNA的表达水平;随后收集结核患者的痰液标本处理后,提取总RNA,进行实时荧光定量PCR检测痰液中的差异表达的miRNA水平。结果 H37Rv体外刺激THP-1细胞,使用miRNA微阵列芯片分析,结果显示：miR-155、miR-29b-1*、miR-150、miR-146a、miR-212和miR-483-5p 共计6个miRNAs水平在3个时间点升高均较为明显;将来自不同区域的120株结核菌株分别与THP-1细胞的共培养24 h,检测发现miR-155表达水平最高;以miRNA-155为检测靶标,对68例结核患者的痰液进行检测,灵敏度和特异度分别为94.1%和93.8%。其灵敏度高于痰涂片的22.1%和结核抗体的83.8% ,差异具有统计学意义（P<0.05）。但与ELISpot法的97.1%,差异无统计学意义（P>0.05）。在对痰涂片阳性结果与miRNA检测结果相关性分析中,发现miR-155其表达水平与痰涂片阳性等级呈正相关（R²=0.743, P<0.05）。结论 此研究提示miR-155能够作为活动性结核诊断的有效靶标,且对间接评估患者肺部荷菌量有重要意义。     

Evaluation of a risk assessment questionnaire used to target tuberculin skin testing in children

CONTEXT: Universal tuberculin skin testing of children has been shown to be costly and inefficient. In response, several authorities have recommended targeted screening based on epidemiological risk. In 1996, the New York City Department of Health (NYCDOH) developed questions to identify children who require a tuberculin skin test. OBJECTIVE: To determine the sensitivity, specificity, and predictive validity of the NYCDOH tuberculosis risk assessment questionnaire. DESIGN: Prospective criterion standard study in which tuberculin skin tests and the NYCDOH questionnaire were administered simultaneously between August 1996 and January 1998. Specific questions asked about contact with a tuberculosis case, birth in or travel to endemic areas, regular contact with high-risk adults, and human immunodeficiency virus infection in the child. SETTING: Ambulatory clinic in South Bronx, New York, NY. PARTICIPANTS: Consecutive sample of 2920 children aged 1 to 18 years. MAIN OUTCOME MEASURES: Sensitivity, specificity, positive and negative predictive values of the questionnaire, and odds ratio (OR) of reactive skin test results. RESULTS: The NYCDOH questionnaire identified 413 children (14%) as having at least 1 risk factor. Of these, 23 (5.6%) had a positive skin test result; 4 (0.16%) of the 2507 without risk factors had a positive result. Results for the full NYCDOH questionnaire were sensitivity, 85.2%; specificity, 86.0%; negative predictive value, 99.8%; positive predictive value, 5.4%; and OR, 35.2 (95% confidence interval, 12.1-102.4). CONCLUSION: The NYCDOH questionnaire is a valid instrument for identifying children for tuberculin skin testing.     

Influence of co-morbidity in the interpretation of tuberculin skin reactivity in multi-ethnic adult patients with tuberculosis

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.     

γ-干扰素释放试验联合细胞因子检测对菌阴肺结核的诊断价值

目的 分析γ-干扰素释放试验联合细胞因子检测对菌阴肺结核的诊断价值,为临床诊断和治疗提供参考依据。方法 对61例菌阴肺结核组、65例肺炎组以及50例对照组依次检测血浆γ-干扰素释放试验的含量,同时采用ELISA方法分别检测IL-1RA、IL-2、IP-10和 MCP-1血浆的水平,所得数据采用SPSS 25.0软件进行统计学分析。结果 菌阴肺结核组血清IGRAs阳性率最高96.7%（59/61）,肺炎组占第二位66.2%（43/65）,对照组血清最低2.0% （1/50）,三组阳性率比较差异均有统计学意义（P<0.05）;菌阴肺结核组、肺炎组和对照组的年龄、男女IGRAs发生阳性率分别比较,差异均无统计学意义（P>0.05）;菌阴肺结核组与对照组、肺炎组和对照组的IL-1RA、IL-2、IP-10和 MCP-1检测水平分别比较,均有统计学意义（P<0.05）;比较菌阴肺结核组与肺炎组的MCP-1检测水平,差异有统计学意义 （P<0.05）;分别比较菌阴肺结核组与肺炎组的IL-2、IP-10和IL-1RA检测水平,差异均无统计学意义（P>0.05）;“IGRAs-IL-1RA-IL-2-IP-10-MCP-1”联合检测的灵敏度最高为86.9%,“IGRAs+IL-1RA+IL-2+IP-10+MCP-1”联合检测的特异度最高,为88.5%,分别高于IGRAs（77.0%）和IL-2（62.3%）的单项检测。结论 菌阴肺结核组IGRAs阳性率明显优于肺炎组和对照组;年龄和性别都不是IGRAs阳性率发生的独立影响因素;IL-1RA、IL-2、IP-10和 MCP-1对于鉴别诊断菌阴肺结核组与肺炎组、肺炎组与对照组可能具有一定的价值;MCP-1具有成为新的生物学标志物指标的潜质;IGRAs联合细胞因子检测能够提高菌阴肺结核的诊断价值。     

A prospective longitudinal study evaluating a T-cell-based assay for latent tuberculosis infection in health-care workers in a general hospital in Beijing

Background The health-care workers (HCWs) are at high risk of acquiring infection with Mycobacterium tuberculosis.The objectives of this study were to compare the performance of the T-SPOT.TB and tuber...     

Violence in the emergency department: a survey of health care workers

BACKGROUND: Violence in the workplace is an ill-defined and underreported concern for health care workers. The objectives of this study were to examine perceived levels of violence in the emergency department, to obtain health care workers' definitions of violence, to determine the effect of violence on health care workers and to determine coping mechanisms and potential preventive strategies. METHODS: A retrospective written survey of all 163 emergency department employees working in 1996 at an urban inner-city tertiary care centre in Vancouver. The survey elicited demographic information, personal definition of violence, severity of violence, degree of stress as a result of violence and estimate of the number of encounters with violence in the workplace in 1996. The authors examined the effects of violence on job performance and job satisfaction, and reviewed coping and potential preventive strategies. RESULTS: Of the 163 staff, 106 (65%) completed the survey. A total of 68% (70/103) reported an increased frequency of violence over time, and 60% (64/106) reported an increased severity. Most of the respondents felt that violence included witnessing verbal abuse (76%) and witnessing physical threats or assaults (86%). Sixty respondents (57%) were physically assaulted in 1996. Overall, 51 respondents (48%) reported impaired job performance for the rest of the shift or the rest of the week after an incident of violence. Seventy-seven respondents (73%) were afraid of patients as a result of violence, almost half (49%) hid their identities from patients, and 78 (74%) had reduced job satisfaction. Over one-fourth of the respondents (27/101) took days off because of violence. Of the 18 respondents no longer working in the emergency department, 12 (67%) reported that they had left the job at least partly owing to violence. Twenty-four-hour security and a workshop on violence prevention strategies were felt to be the most useful potential interventions. Physical exercise, sleep and the company of family and friends were the most frequent coping strategies. INTERPRETATION: Violence in the emergency department is frequent and has a substantial effect on staff well-being and job satisfaction.