Prevalence and risk factors of latent tuberculosis infection in close contacts with tuberculosis patients among non-resident populations in Shanghai,China

<正>Objective To investigate the prevalence of latent tuberculosis(TB)infection(LTBI),and to identify the riskfactors in close contacts of pulmonary TB patients among non-resident population in Shanghai.Methods The study subjects were the close contacts of pulmonary TB patients among non-resident populations in Xuhui,Minhang and     

Performance and correlation of QuantiFERON-TB Gold,T-SPOT.TB and tuberculin skin test in young children with or exposed to tuberculosis

Objective: To evaluate the performance of interferon gamma release assays and tuberculin skin test in Bacillus Calmette-Guerin vaccinated young children. Methods: A cross-sectional study was conducted in healthy children younger than 5 years who were recently diagnosed with tuberculosis or had recent exposure to active tuberculosis. QuantiFERON-TB Gold, T-SPOT.TB and tuberculin skin test were performed in each patient. Results: Of the 60 children, median age 3.3 years, 17 had tuberculosis and 43 had recent tuberculosis exposure. Overall, 15(25.0%) children had tuberculin skin test reaction ≥10 mm; 8(13.3%) were positive by QuantiFERON-TB Gold In-Tube test, and 12(20.0%) by T-SPOT.TB. Nineteen(31.7%) children had at least one positive test. There was a moderate agreement between interferon gamma release assays and tuberculin skin test. Conclusions: The positive rates of interferon gamma release assays and tuberculin skin test were low in young children who were infected with tuberculosis, supporting the management strategy of not testing children younger than 5 years.     

Significant risk and associated factors of active tuberculosis infection in Korean patients with inflammatory bowel disease using anti-TNF agents

AIM:To evaluate the incidence and risk factors of Korean tuberculosis(TB) infection in patients with inflammatory bowel disease(IBD) undergoing anti-TNF treatment.METHODS:The data of IBD patients treated with anti-TNFs in 13 tertiary referral hospitals located in the southeastern region of Korea were collected retrospectively.They failed to show response or were intolerant to conventional treatments,including steroids or immunomodulators.Screening measures for latent TB infection(LTBI)and the incidence and risk factors ofactive TB infection after treatment with anti-TNFs were identified.RESULTS:Overall,376 IBD patients treated with antiTNF agents were recruited(male 255,mean age of anti-TNF therapy 32.5±13.0 years);277 had Crohn’s disease,99 had ulcerative colitis,294 used infliximab,and 82 used adalimumab.Before anti-TNF treatment,screening tests for LTBI including an interferon gamma release assay or a tuberculin skin test were performed in 82.2%of patients.Thirty patients(8%)had LTBI.Sixteen cases of active TB infection including one TB-related mortality occurred during 801 personyears(PY)follow-up(1997.4 cases per 100000 PY)after anti-TNF treatment.LTBI(OR=5.76,95%CI:1.57-21.20,P=0.008)and WBC count5000 mm3(OR=4.5,95%CI:1.51-13.44,P=0.007)during follow-up were identified as independently associated risk factors.CONCLUSION:Anti-TNFs significantly increase the risk of TB infection in Korean patients with IBD.The considerable burden of TB and marked immunosuppression might be attributed to this risk.     

Nutritional status of children with inflammatory bowel disease in Saudi Arabia

AIM: To assess the prevalence of nutritional disorders in children with inflammatory bowel disease(IBD) in Saudi Arabia.METHODS: The data from a national cohort of children newly diagnosed with IBD between 2003 and 2012 were analyzed. The diagnosis of IBD and the differentiation between Crohn’s disease(CD) and ulcerative colitis(UC) were confirmed by gastroenterologists according to the standard criteria. The body mass index(BMI) of each child [weight(kg)/height~2(m)] was calculated at the time of diagnosis. The World Health Organization standards and references were used and the BMI for age > +1 and <-2 standard deviation score were used to define overweight and thinness, respectively. Age stratification analysis was performed to investigate any age-related variation in the prevalence of nutritional status between children < 10 years of age and older.RESULTS: There were 374 children from 0.33 to 17 years of age, including 119(32%) children with UC and 255(68%) with CD. All of the children were Saudi nationals, and 68(57%) of the UC and 150(59%) of the CD children were males. A positive history of anorexia at the time of diagnosis was found in 30(25%) patients with UC and 99(39%) patients with CD. The prevalence of thinness was 31%, 35% and 24% in children with IBD, CD and UC, respectively, with a significantly higher prevalence of thinness in children with CD than in children with UC(P = 0.037) only in the age group of 10-17 years(P = 0.030). The prevalence of overweight was 16 %, 15% and 20 % in the children with IBD, CD and UC, respectively, indicating a higher prevalence in UC that was statistically significant only in the age group of 10-17 years(P = 0.020). CONCLUSION: A high proportion of children with IBD presented with overweight instead of the classical underweight. Awareness of this finding is important for patient care.     

Evaluation of T-SPOT.TB assay in the diagnosis of pulmonary tuberculosis within different age groups

<正>Objective To evaluate the value of T-SPOT.TB assay in the diagnosis of pulmonary tuberculosis within different age groups.Methods We analyzed 1 518 suspected pulmonary tuberculosis(PTB)patients who were admitted to the Beijing Chest Hospital from November 2012to February 2014 and had valid T-SPOT.TB tests before     

Fluoroquinolones for the treatment of latent Mycobacterium tuberculosis infection in liver transplantation

Solid organ transplantation(SOT)is the best treatment option for end-stage organ disease.Newer immunosuppressive agents have reduced the incidence of graft rejection but have increased the risk of infection,particularly due to the reactivation of latent infections due to opportunistic agents such as Mycobacterium tuberculosis.Active tuberculosis(TB)after SOT is a significant cause of morbidity and mortality.Most cases of posttransplant TB are secondary to reactivation of latent tuberculosis infection(LTBI)due to the effects of long-term immunosuppressive therapy.Risk minimization strategies have been developed to diagnose LTBI and initiate treatment prior to transplantation.Isoniazid with vitamin B6 supplementation is the treatment of choice.However,liver transplantation(LT)candidates and recipients have an increased risk of isoniazid-induced liver toxicity,leading to lower treatment completion rates than in other SOT populations.Fluoroquinolones(FQs)exhibit good in vitro antimycobacterial activity and a lower risk of drug-induced liver injury than isoniazid.In the present review,we highlight the disease burden posed by posttransplant TB and summarize the emerging clinical evidence supporting the use of FQs for the treatment of LTBI in LT recipients and candidates.     

Enhancement of vitamin A combined vitamin D supplementation on immune response to Bacille Calmette-Guerin vaccine revaccinated in Chinese infants

Objective:To investigate whether there is an association between diameter of bacille CalmetteGuerin(BCG)sears and effect of purified protein derivative(PPD)reaction anil to determine whether vitamin A(VA)combined vitamin I)(VD)supplementation influences the immune response to BCG revueeinated in Chinese infants.Methods:A cross-section and 3-month community-randomised trial was conducted.A total of 5 629 infants at 3,6 and 12 months of age in Junan County of China were examined for BCG scar fonnation.Then,597 revuccinated infants were randomly assigned to supplementation(n=307)and control(n=290)groups.The supplementation group were daily assigned to 1 500 IU VA and 500 IU VD for 3 months.Then all infants were subjected to skin test with PPD.Results:The diameter of BCG sears was positively con-elated with diameter of skin indurations of PPD(r=0.17,P0.05)in the 5 629 infants.The rate of positive response to PP1)was higher in the supplementation group than in the control group(96.1%versus 89.7%,P0.05,prevalence ratio 1.07.95%CI 1.02-1.12).The prevalence ralio of PPD response for the supplementation group compared with that for the control group was 1.07(95%CI 1.01-1.13)for the males and 1.08(95%CI 1.00-1.17)for the females.For the supplementation group,the males got larger tuberculin induration than the females[(0.73±0.2l)cm versus(0.67±0.20)cm.P0.05)after intervention.Conclusions:The diameter of BCG scars was effectively correlated with PPD response,which indicates BCG scar formation may be an useful tool Io evaluate the effect of tuberculosis prevention.VA combined VD supplementation may play an immunoregulatory rale in BCG revuecination.This may contribute to the prevention of childhood tuberculosis.     

Drug resistance pattern of Mycobacterium tuberculosis isolates from patients of five provinces of Iran

Objective:To determine the patterns of resistance to first line anti-tuberculosis(TB)drugs among a collection of Mycobacterium tuberculosis(MTB)isolates from 5 provinces of Iran.Methods:A total of the 6 426 clinical specimens from patients suspected of active TB were collected from March 2010 to June 2012.All specimens were subjected for microscopy and culture tests in the TB centers of studies provinces.Drug susceptibility testing to the first line anti-TB drugs for culture positive MTB was performed on Lwenstein-Jensen(LJ)medium using proportion method.Results:Of 6 426 clinical specimens,261 were culture positive for mycobacteria,of which 252 were MTB and 9 were MOTT(mycobacteria other than tuberculosis).Of 252 MTB isolates.211(83.7%)were pan-susceptible and 41(16.3%)were resistant to at least one drug.Resistance was most common to streptomycin.30 isolates(12.0%),followed by isoniuzid,20isolates(8.0%),rifampin,15 isolates(6.0%)and ethambutol,14 isolates(5.5%).Sixteen(6.3%)MTB isolates were MDR.A clear evidence of heterogeneity amongst the 5 provinces in the proportions with resistance to one or more drugs was observed[χ~2=12.209(4 degrees of freedom),P values=0.015 9].Conclusions:The prevalence of drug resistance in this study area underscoring the need for further enforcement of TB control strategies in the Iran.Drug susceptibility testing for all TB cases to provide optimal treatment,establishing advanced diagnostic facilities for rapid detection of MDR-TB and continuous monitoring of drug resistance are recommended for prevention and control of drug-resistant TB.     

Prevalence,intensity of infection and risk factors of urinary schistosomiasis in preschool and school aged children in Guma Local Government Area,Nigeria

Objective:To determine the prevalence and intensity of infection and the risk factors associated with urinary schistosomiasis in pre—school and school aged children in Cuma Local Government Area of Benue State,Nigeria.Methods:Urine filtration technique using polycarbonate membrane filters was employed to process urine specimens and to determine presence of Schistosoma haematobium eggs in urine.Questionnaires were also administered to children to collect information on socio-demographic data and water-contact activities.Results:An overall prevalence of 55.0%(165/300)was recorded out of the 300 urine samples examined.Prevalence of infection varied between 36.0%-64.0%with a significant difference(X~2=11.59,P=0.041)between the different communities visited.Males were more infected(60.6%,103/170)than females(47.7%,62/130)with a significant difference(X~2=4.95,P=0.026).The age-related prevalence showed higher prevalence(70.5%,36/52)in the 11-15 year old children than that in the 1-5 year old ones(44.9%,53/118).A significant difference was observed in the prevalence between the age groups(X~2=10.56,P=0.014).The prevalence of light intensity of infection(1-49 eggs/10 mL of urine)(86.6%)was significantly higher than that of heavy intensity of infection(5=50 eggs/10 mL of urine)(13.3%)in the area(t=16.48,P=0.000).Water contact activities of the children revealed that children that were involved in irrigation and those that went swimming in water bodies were observed to be at higher risk of becoming infected with urinary schistosomiasis in the area with odd ratios(risk factors)of 2.756(1.334-5.693)and 2.366(1.131-4.948)respectively at P0.05 level.Conclusions:The study revealed the hyperendemicily of urinary schistosomiasis in the preschool and school aged children in Guma Local Government Area.It is therefore recommended that praziquantel should be administered to children in the area and systematic epidemiological studies should be undertaken in the whole Local Government Area and the State at large to discover new foci of infection.     

Prevalence and intensity of soil-transmitted helminth infections among school-age children in the Cagayan Valley,the Philippines

Objective: To identify the prevalence of soil-transmitted helminthiasis(STH) among school-age children in the Cagayan Valley, the Philippines, assess their level of awareness on the disease, and determine predisposing factors of the disease.Methods: A total of 478 Grades Ⅲ-Ⅴschool-age children in Pamplona and Sanchez-Mira School Districts in the Cagayan Valley answered the questionnaire assessing their knowledge, attitude, and practices on STH, subjected to anthropometric measurements, and provided faecal samples for parasitologic assessment(direct smear, Kato-Katz, and formol-ether concentration techniques). Results: The participants of the study, with 55.86% females, were 8 to 14 years old. Their nutritional status was assessed ‘normal’(84.31%), ‘severely wasted’(6.49%), ‘wasted’(5.23%), ‘overweight’(2.72%), and ‘obese’(1.26%). The prevalence of infection with at least 1 STH species was 25.99% in Pamplona and 19.40% in SanchezMira. Overall, the prevalence of heavy intensity was 7.11% for Ascaris lumbricoides and 1.67% for Trichuris trichiura. All hookworm infections had light intensities. The majority of the school-age children had a low score in the KAP test. In knowledge of STH, ‘stunted growth as a symptom of infection’ was associated with a lower risk of Ascaris lumbricoides infection(OR 0.448; 95% CI 0.212, 0.945; P=0.035) while ‘playing with soil as a mode of transmission’ was associated with an increased risk of Ascaris lumbricoides infection(OR 2.067; 95% CI 1.014, 4.212; P=0.046). In attitude towards STH, ‘I think I have intestinal worm now’ was associated with a higher risk of Ascaris lumbricoides infection(OR 1.681; 95% CI 1.061, 2.662; P=0.027).Conclusions: The prevalence rate of Ascaris lumbricoides among the school-age children in the Cagayan Valley shows the need to further intensify intervention in the area to meet the threshold set by the World Health Organization. The identified predictors of infection, which concerns the school-age children's knowledge and attitude toward STH, can be used in augmenting intervention programs in the future.     

Is the T-cell-based interferon-gamma releasing assay feasible for diagnosis of latent tuberculosis infection in an intermediate tuberculosis-burden country?

The diagnosis of active and latent tuberculosis infection (LTBI) remains a challenge, especially in light of the fact that the tuberculin skin test (TST), which has been used to diagnose LTBI for over a century, has many well-known drawbacks. This study aimed to compare the diagnostic performance of the T-cell-based interferon-gamma releasing assay (IGRA) T-SPOT.TB with the TST for the diagnosis of LTBI in an intermediate tuberculosis (TB)-burden country with high BCG coverage. For this purpose, a total of 91 participants, including culture-confirmed TB patients, healthy contacts known to have been exposed to Mycobacterium tuberculosis, and healthy volunteers, selected from a BCG-vaccinated population were recruited. The sensitivities of the T-SPOT.TB and TST were 79.3 and 25.8%, and the specificities were 75.9 and 56.7%, respectively. The negative- and positive-predictive values for T-SPOT.TB and TST were 78.6 and 76.7% and 42.5 and 38.1%, respectively. The diagnostic performance of the TST in LTBI diagnosis is therefore severely diminished in BCG-vaccinated populations, with the sensitivity and specificity of the T-SPOT.TB assay being markedly higher. IGRAs have been reported to have higher diagnostic sensitivity and specificity in low TB-incidence settings than those seen here. Further larger scale studies in high and intermediate TB-incidence settings are therefore warranted.     

Contribution of a IFN-gamma assay in contact tracing for tuberculosis in a low-incidence, high immigration area

AIMS OF STUDY: to analyse, in contacts exposed to smear+/culture + (S+/C+) or S-/C+ TB, most of whom are foreign-born: 1) correlation between T-SPOT.TB IFN-gamma release assay (Oxford Immunotec, UK), TST and exposure scores; 2) agreement between T-SPOT.TB and TST in Bacillus of Calmette-Guérin (BCG) vaccinated and non-vaccinated subjects, and 3) impact of results of T-SPOT.TB on diagnosis and treatment for latent tuberculosis infection (LTBI). PATIENTS AND METHODS: TST and T-SPOT.TB were performed in 295 contacts (74% foreign-born) 8-12 weeks after exposure. Contacts completed five exposure scores. Data were analysed according to most recent US (ATS/CDC), British (NICE) and Swiss guidelines. RESULTS: T-SPOT.TB was positive in 115 (39%) and indeterminate in 15 subjects (5.1%). Neither TST, nor T-SPOT.TB was significantly related to exposure scores or infectiousness of the index case. In multivariate analysis, incidence of TB in country of origin was the strongest predictor of result of TST or T-SPOT.TB. Agreement between TST and T-SPOT.TB (kappa: 0.19-0.27) was low but improved in non BCG-vaccinated subjects (kappa: 0.28-0.47). According to guidelines referred to, 10-24% of subjects screened were T-SPOT.TB+/TST-: the prognosis of this group is yet undetermined. Another 10-27% were T-SPOT.TB-/TST+: present guidelines recommend withholding treatment for LTBI in these subjects although longitudinal data are still scarce. CONCLUSIONS: The lack of a relationship between T-SPOT.TB and exposure scores probably results from both the variability inherent to the design of this study (ie, multiple contact investigations, exposure in different settings) and limits in the performance of the IGRA tested. Longitudinal data are needed to clarify the risk of TB in T-SPOT.TB+/TST- individuals. Unreliability of diagnosis of LTBI in spite of the present use of IGRA in algorithms is illustrated by the wide variations in identification of LTBI according to different guidelines referred to.     

涂阳肺结核患者密切接触者结核感染及危险因素分析

目的了解涂阳肺结核患者密切接触者结核感染情况及影响因素。方法采用T-SPOT.TB试剂盒检测与76例涂阳肺结核患者的243例密切接触者结核潜伏感染(LTBI)情况,采用Pearsonχ2检验分析LTBI的影响因素。结果 248例密切接触者中活动性肺结核检出率为2.02%,在243例密切接触者(剔除5例活动性肺结核患者)中T-SPOT.TB的阳性率为46.9%,经单因素分析显示于涂阳肺结核患者确诊前2个月内接触者及夫妻关系的密切接触者,LTBI危险性高,且差异有统计学意——分别为(χ2=6.925,P=0.006)和(χ2=8.447,P=0.038)。结论与涂阳肺结核患者密切接触者较普通人群结核感染发生率高,且不同接触人群LTBI发生比率不同。     

Community-wide INH treatment of latent TB infection in a BCG-vaccinated population: experience in rural Taiwan.

SETTING: A contiguous four-village bacille Calmette-Guérin (BCG) vaccinated population (n = 1785) in an aboriginal township in Taiwan with a very high tuberculosis (TB) burden. OBJECTIVE: To report our experience in this first community-wide effort in Taiwan to treat latent tuberculosis infection (LTBI) in household contacts of recently diagnosed TB cases. RESULTS: Overall, 71 LTBI cases (88.8%) completed varying case-specific isoniazid treatment courses, accounting for 4.0% of the affected community (village range 2.4-7.5%, P < 0.001). CONCLUSION: LTBI in household contacts was successfully identified and treated in a very high TB burden BCG-vaccinated area in rural Taiwan, complementing standard TB control measures.     

Tuberculin reactivity in bacille Calmette-Guérin vaccinated populations: a compilation of international data.

SETTING: The effect of previously administered bacille Calmette-Guérin (BCG) vaccine on subsequent tuberculin skin tests (TSTs) complicates screening for latent tuberculosis infection (LTBI) in foreign-born persons. OBJECTIVE: To determine the usefulness of the TST as a screening test for LTBI in foreign-born persons. DESIGN: A literature search was performed of published studies that compared tuberculin reactivity amongst BCG-vaccinated and non-vaccinated groups. The percentages of positive reactors in the two groups were then used to calculate a prevalence ratio. RESULTS: The prevalence ratio varied with the age of the groups tested and the incidence of TB in their countries of origin. The TST performed poorly in vaccinated persons of all ages from countries of low TB incidence, but was a useful screen for LTBI in vaccinated adults from countries of high and intermediate incidence. The test performed poorly as a screening method for vaccinated children under 2 years of age. Its usefulness in vaccinated children aged 2-14 years varied considerably. CONCLUSIONS: The usefulness of the TST as a screening method for LTBI depends on the age of the patient and the incidence of TB in their country of origin.     

Latent tuberculosis infection treatment and T-cell responses to Mycobacterium tuberculosis-specific antigens

RATIONALE: There is currently no available test for monitoring the effect of treatment of latent tuberculosis infection (LTBI) to indicate cure or predict risk of subsequent progression to disease. OBJECTIVE: We used the T-SPOT.TB assay, which measures T-cell interferon-gamma responses to the Mycobacterium tuberculosis-specific peptides early secretory antigenic target 6-kD protein (ESAT-6) and culture filtrate protein 10 (CFP-10), to determine the effect of LTBI treatment on these responses. METHODS: A total of 226 tuberculosis contacts with positive T-SPOT.TB results underwent repeat testing on LTBI treatment completion. The majority (96%) received 6 months of isoniazid. The pre- and post-treatment T-SPOT.TB results were analyzed according to the combined and separate responses to ESAT-6 and CFP-10 antigens. RESULTS: The T-SPOT.TB reverted to negative in 85 (37.6%) contacts at treatment completion. Treatment had a significant effect on the response to CFP-10 (p < 0.001; reversion rate, 48.6%), but not on the response to ESAT-6 (p = 0.081; reversion rate, 21.6%). The median number of spot-forming cells (SFCs)/2.5 x 10(5) peripheral blood mononuclear cells (PBMCs) pre- and post-treatment was 6 versus 4.5 for ESAT-6 (p = 0.116) and 11 versus 4 for CFP-10 (p < 0.001). There was a significant difference between the change (fall) in the pre- and post-treatment responses to CFP-10 (6 SFCs/2.5 x 10(5) PBMCs) and ESAT-6 (0 SFCs/2.5 x 10(5) PBMCs; p < 0.001). Significantly different age-related T-cell responses to the two antigens were found. CONCLUSION: LTBI treatment had a differential effect on T-cell responses to ESAT-6 and CFP-10 as measured by the T-SPOT.TB. The quantitative response to CFP-10 may be a useful LTBI treatment-monitoring tool.     

Comparison of positive tuberculin skin test with an interferon-gamma-based assay in unexposed children

A false-positive tuberculin skin test (TST) may be a result of T-cell sensitivity due to Bacille Calmette-Guerin (BCG) vaccination or exposure to non-tuberculous mycobacteria, thus leading to unnecessary isoniazid preventive therapy, especially in low-risk populations. Unlike TST, T-SPOT.TB is not confounded by BCG vaccination or exposure to most of the other non-tuberculous mycobacteria, because this assay is based on enumeration of interferon-gamma-secreting T cells in response to Mycobacterium tuberculosis-specific antigens. We compared the TST with T-SPOT.TB with respect to different TST cut-off points in healthy unexposed BCG-vaccinated schoolchildren. A total of 209 children between 6 and 10 years of age with a TST induration of 0 (n = 50), 10 - 14 (n = 45), 15 - 19 (n = 95) and > or =20 mm (n = 19) were enrolled. Among TST-positive subjects, only 26 (23%) were positive with T-SPOT.TB, and T-SPOT.TB was positive in 4, 7, 20 and 42% of children with TST indurations of 0, 10 - 14, 15 - 19 and > or =20 mm, respectively. We suggest that confirmation of a positive TST by the interferon-gamma-based test would reduce unnecessary preventive therapy significantly in healthy unexposed BCG-vaccinated children.     

Yield and cost effectiveness of mycobacterial infection detection using a simple IGRA-based protocol in UK subjects with inflammatory bowel disease suitable for anti-TNFα therapy

Background and aimsTesting for LTBI is recommended prior to anti-TNFα agents. This includes an assessment of TB risk factors, chest radiograph, and interferon-gamma release assay alone or with concurrent Tuberculin skin testing. Here we review our experience and cost-effectiveness of using T-SPOT.TB IGRA to detect mycobacterial infection in patients with IBD suitable for anti-TNFα therapy.MethodsThis was a single-centre, retrospective review and economic evaluation (compared to British Thoracic Society guidance) of 125 adult IBD patients (90 anti-TNFα naïve, 35 established on anti-TNFα) tested for LTBI using T-SPOT.TB IGRA.ResultsAll subjects had normal chest radiographs and no clinical evidence for TB. 109 (87%) were BCG vaccinated. 27 (22%) of all patients tested were not using immunomodulation at the time of testing. 66 (53%) were taking thiopurines, 22 (18%)corticosteroids, and 35 (28%) anti-TNFα agents. One hundred twenty two (98%) had a negative IGRA result, two (2%) had positive results, and one (1%) had an indeterminate IGRA. A strategy using IGRA to guide TB preventative treatment produced cost savings of £10.79 per person compared to the BTS guidance. Eighty eight percent of the anti-TNFα naïve group have subsequently received treatment with either infliximab or adalimumab (median follow-up of 24 months, IQR 18–30) with no cases of TB disease occurring.ConclusionsThe use of a simple screening protocol for LTBI incorporating T-SPOT.TB IGRA in place of TST in a largely BCG vaccinated population, many using immunomodulatory agents, appears to work well and is a cost-effective strategy in our IBD service.     

Present activity of BCG and LTBI treatment for infants in Japan

I analyzed the BCG vaccination and treatment of latent tuberculosis infection (LTBI) for infants notified in 2008 in Japan. BCG was not recommended and treatment of LTBI was the main activity for prevention of TB in infants from birth to age 2 months. The majority of notified LTBI cases were detected by contact surveys. Out of the estimated number of TB infected (148), only 2 cases were notified based on the outcome of LTBI treatment for 89 infants. When the infants were 3-5 months old, both BCG vaccination and LTBI treatment were implemented. BCG coverage was 61.5-97.7%, and LTBI treatment for non-vaccinated individuals was applied for a larger number of infants (1.04 to 7.82 times as many) than the estimated number of infants infected with TB. The majority of infants were BCG vaccinated when they were 6-11 months old. Although LTBI treatment coverage was low, only 5 cases developed among those receiving BCG vaccination. During 1-2 year, BCG coverage was high and breakdown rates of BCG-vaccinated children were much lower than those of non-vaccinated children. This difference might be due to not only the preventive effect of BCG but also risk difference of TB infection between BCG-vaccinated and BCG non-vaccinated individuals. The number of notified LTBI treatment cases was lower than the estimated number of children infected with TB during 1-2 year. To prevent infant TB, reinforcement of contact surveys to identify LTBI for treatment, improvement of BCG coverage, and attention to BCG non-vaccinated infants older than 6 months might be effective.     

Contact tracing using a new T-cell-based test: better correlation with tuberculosis exposure than the tuberculin skin test.

SETTING: Residential institution for alcoholics in Switzerland. OBJECTIVE: To compare the results of the tuberculin skin test (TST) and the new T-cell-based test for tuberculosis infection (T-SPOT.TB) in subjects exposed to a case of smear-positive pulmonary TB (PTB). DESIGN: After the notification of smear-positive PTB in a resident of an institution for alcoholics, contacts underwent TST and determination of Mycobacterium tuberculosis specific T-cells in blood by T-SPOT.TB. Results were analysed according to age, history of BCG vaccination, and level of exposure to the index case. RESULTS: There was no correlation between the level of exposure and the TST results, but the T-SPOT.TB results were significantly correlated with the level of exposure (P = 0.029, OR 5.00, 95%CI 1.05-23.86). Contacts who had been previously BCG-vaccinated were significantly more likely to have a positive TST than unvaccinated contacts (52% vs. 0%, P = 0.0003), but there was no influence of prior BCG vaccination on T-SPOT.TB results. CONCLUSIONS: T-SPOT.TB test results correlated better than TST with level of exposure to M. tuberculosis and were not confounded by prior BCG vaccination. This test allows better selection of contacts who should receive treatment for latent TB infection.