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Contacts of adults with tuberculosis (TB) are at risk for infection. Tests based on interferon-[gamma] (IFN-[gamma]) expression in response to Mycobacterium tuberculosis antigens may be more sensitive than the tuberculin [...]

Abstract Background Although tuberculosis (TB) is a minor problem in Denmark, severe and complicated cases occur in HIV positive. Since the new M. tuberculosis specific test for latent TB, the QuantiFERON-TB In-Tube test (QFT-IT) became available the patients in our clinic have been screened for the presence of latent TB using the QFT-IT test. We here report the results from the first patients screened. Methods On a routine basis the QFT-IT test was performed and the results from 590 HIV positive individuals consecutively tested are presented here. CD4 cell count and TB risk-factors were recorded from patient files. Main findings 27/590(4.6%) of the individuals were QFT-IT test positive, indicating the presence of latent TB infection. Among QFT-IT positive patients, 78% had risk factors such as long-term residency in a TB high endemic area (OR:5.7), known TB exposure (OR:4.9) or previous TB disease (OR:4.9). The prevalence of latent TB in these groups were 13%, 16% and 19% respectively. There was a strong correlation between low CD4 T-cell count and a low mitogen response (P < 0.001;Spearman) and more patients with low CD4 cell count had indeterminate results. Conclusion We found an overall prevalence of latent TB infection of 4.6% among the HIV positive individuals and a much higher prevalence of latent infection among those with a history of exposure (16%) and long term residency in a high endemic country (13%). The QFT-IT test may indeed be a useful test for HIV positive individuals, but in severely immunocompromised, the test may be impaired by T-cell anergy.

Introduction: Two cases of tuberculosis were diagnosed at a high school. A contact investigation using Mantoux test (TST) and QuantiFERON TB in Tube test (QFT) was conducted in order to compare QFT with TST., Methods: A total of 787 individuals were invited to participate, of whom 734 had a TST applied and 490 a QFT test done., Results: Of the skin test applied 689 (94%) were read, and 41 (5.9%) were positive. TSTs were positive in 17/603 (2.8%) students and 24/87 (28%) staff members. A total of 490 (62%) had a QFT performed; 11 (2.2%) were positive and four (0,8%) inconclusive. QFT positive results were found in 8/419 (1.9%) students and 3/71 (4.2%) staff members. Agreement between the TST and the QFT was moderate 97% (Kappa 0.407; confidence interval (CI) 0.124-0.689) among students and poor among staff 68% (Kappa 0.036; CI -0.102-0.175). The majority of the TST-positive and all the QFT positive students were found in relation to the index case. Positive TST results and BCG vaccination (p < 0,05) were associated. Only 5/10 (50%) of the QFT-positive individuals were TST positive, which indicates a suboptimal TST sensitivity., Conclusion: The two tests identified an equal amount of Mycobacterium tuberculosis infected students, whereas a high proportion of the staff were TST positive. The discordant results underline that the two tests do not measure the same and that their sensitivity is not identical. Choice of test should rest on a case-by-case analysis and should be tailored to the desired level of safety and the cost for society and for the patients.

Increasing rates of Clostridium difficile-associated diarrhoea (CDAD) with an unusual, severe course have been reported in Canada, USA and several European countries since 2003. A new virulent strain, PCR ribotype 027 (CD027), is associated with this increase. We report the first Danish case of CDAD caused by CD027. A 85-year-old woman was admitted to hospital with pneumonia. Following treatment initially with penicillin, secondly with moxifloxacin she developed bloody diarrhoea. A stool specimen showed CD027. She was treated with metronidazol for ten days and recovered completely.

Background: Although tuberculosis (TB) is a minor problem in Denmark, severe and complicated cases occur in HIV positive. Since the new M. tuberculosis specific test for latent TB, the QuantiFERON-TB In-Tube test (QFT-IT) became available the patients in our clinic have been screened for the presence of latent TB using the QFT-IT test. We here report the results from the first patients screened., Methods: On a routine basis the QFT-IT test was performed and the results from 590 HIV positive individuals consecutively tested are presented here. CD4 cell count and TB risk-factors were recorded from patient files., Main Findings: 27/590(4.6%) of the individuals were QFT-IT test positive, indicating the presence of latent TB infection. Among QFT-IT positive patients, 78% had risk factors such as long-term residency in a TB high endemic area (OR:5.7), known TB exposure (OR:4.9) or previous TB disease (OR:4.9). The prevalence of latent TB in these groups were 13%, 16% and 19% respectively. There was a strong correlation between low CD4 T-cell count and a low mitogen response (P < 0.001;Spearman) and more patients with low CD4 cell count had indeterminate results., Conclusion: We found an overall prevalence of latent TB infection of 4.6% among the HIV positive individuals and a much higher prevalence of latent infection among those with a history of exposure (16%) and long term residency in a high endemic country (13%). The QFT-IT test may indeed be a useful test for HIV positive individuals, but in severely immunocompromised, the test may be impaired by T-cell anergy.

The majority of healthy individuals exposed to Mycobacterium tuberculosis will not develop disease and identifying what constitutes "protective immunity" is one of the holy grails of M. tuberculosis immunology. It is known that IFN-gamma is essential for protection, but it is also apparent that IFN-gamma levels alone do not explain the immunity/susceptibility dichotomy. The controversy regarding correlates of immunity persists because identifying infected but healthy individuals (those who are immune) has been problematic. We have therefore used recognition of the M. tuberculosis virulence factor early secretory antigenic target 6 to identify healthy, but infected individuals from tuberculosis (TB)-endemic and nonendemic regions (Ethiopia and Denmark) and have compared signals for cytokines expressed directly ex vivo with the pattern found in TB patients. We find that TB patients are characterized by decreased levels of Th1 cytokines and increased levels of IL-10 compared with the healthy infected and noninfected community controls. Interestingly, the healthy infected subjects exhibited a selective increase of message for the IL-4 antagonist, IL-4delta2, compared with both TB patients or noninfected individuals. These data suggest that long-term control of M. tuberculosis infection is associated not just with elevated Th1 responses but also with inhibition of the Th2 response.