Immunosurveillance for Mycobacterium tuberculosis of health care personnel in a third level care hospital.

BACKGROUND: Health care workers are at risk for Mycobacterium tuberculosis (MTB) infection. OBJECTIVES: To perform an occupational health survey among 621 employees of a 800-bed third level care hospital covered by MTB surveillance. METHODS: Statistical analysis was applied to results from tuberculin skin test (TST), QuantiFERON - TB Gold in tube assay (QFT), PPD-ELISA for serum antibodies, and occupational or vaccine data. RESULTS: 29.1% of subjects were TST positive, 18.5% were QFT positive. In 23% of subjects no correlation between these tests was found, presumably linked to BCG-vaccination, since TST positivity was 4 times higher among vaccinated subjects, whereas both tests correlated well in unvaccinated subjects. QFT values above 2 IU/ml were significantly associated with positive TST and age over 40 years. Working in MTB risk level 4 was significantly associated with QFT, TST and PPD-antibody levels, suggesting booster effects by repeated exposure. No clear correlation was observed with medical specializations but significantly higher QFTpositivity was found in subjects not assigned to the classical medical professions and originating from MTB high risk areas. CONCLUSIONS: These results shift the focus on maintenance personnel, who mostly worked in MTB risk level 2 areas. The less positive QFT results in vaccinated subjects highlight QFT's advantage as a screening tool and argue for a protective effect of the BCG-vaccine, although percentages of vaccinated persons varied largely between different medical professions. Interestingly, the percentage of QFT positive persons was lower among subjects reporting MTB exposure than those who were not aware of exposure events.

The Italian AIPO study on tuberculosis treatment results, report 1996. National AIPO "Tuberculosis" Study Group. Associazione Italiana Pneumologi Ospedalieri.

In Italy, no national data on tuberculosis (TB) treatment results were available. In 1995, the AIPO (Italian Association of Hospital Pneumologists) TB Study Group, in collaboration with the Istituto Superiore di Sanità (technical branch of the Ministry of Health), started a prospective monitoring activity based on World Health Organization (WHO) and International Union against Tuberculosis and Lung Disease (IUATLD) recommendations. Data were collected from a nationwide network of 41 TB units, managing a significant proportion of all the TB cases notified in Italy each year. The aim of this study was to analyse the case findings and treatment results for the year 1996. Eight hundred and thirty eight TB cases were reported (56% males; 26% immigrants), 708 (84%) being new cases. Of these cases, 565 (67%) were pulmonary, 235 (28%) extrapulmonary and 38 (5%) both pulmonary and extrapulmonary. The main risk factors for TB were a history of recent contact and diabetes among native Italians and recent contact and human immunodeficiency virus-seropositive status among immigrants. The majority of immigrants were from Africa and Asia, and had been in Italy > 24 months before diagnosis of TB. Thirty-six per cent of patients had a positive direct sputum smear examination for alcohol acid-fast bacilli; 37% were resistant to any drug (monoresistance to isoniazid 4.4%; multidrug resistance 10.4%). In 96% of cases, the duration of treatment was < 12 months. The overall success rate (cured plus treatment completed) was 84.1%. A significantly higher percentage of deaths was found in native Italians (being age-related), whereas immigrants had a higher default rate.

[Screening of South Tyrolean school children after exposure to a tuberculosis case]. / Screening-Studie unter Südtiroler Schülern nach Tuberkuloseexposition.

BACKGROUND: During a language course in Ireland 422 schoolchildren aged 15-17 years and 44 accompanying persons from the autonomous Province of Bolzano--South Tyrol in Italy were repeatedly exposed to a Mycobacterium tuberculosis complex culture-positive, but smear-negative Irish teacher for more than 10 lessons. METHODS: Immediate action included contact tracing of exposed persons, administration of a standardised questionnaire, intradermal PPD (5IU) testing and thorax X-ray of persons with an induration of > or = 5 mm in the PPD test. The questionnaire included information on demographic factors, symptoms, vaccination status, underlying diseases, regular medical treatment and past infection in the last three months. A control group of children with similar age and BCG vaccination status was enrolled in the same schools to estimate the effect of exposure and the influence of previous BCG vaccination and ambient non-tuberculous mycobacteria. RESULTS: Exposure in Ireland was not associated with an elevated prevalence of positivity in the PPD test in the exposed group, but having intra-familiar contact with tuberculosis cases (OR = 3.3; 95 % confidence interval: 1.35-8.07) or being from school A (OR = 2.3; 95 % confidence interval: 1.19-4.32) was associated with an induration > or = 5 mm in the multivariate analysis. CONCLUSIONS: Contact tracing is an important public health action after exposure to an infectious tuberculosis case, nevertheless, in this case it may have resulted in overtreatment of exposed persons. BCG vaccination may have a long-term effect on PPD skin testing.

S.A.M., the Italian Martian simulation chamber.

The Martian Environment Simulator (SAM "Simulatore di Ambiente Marziano") is a interdisciplinary project of Astrobiology done at University of Padua. The research is aimed to the study of the survival of the microorganisms exposed to the "extreme" planetary environment. The facility has been designed in order to simulate Mars' environmental conditions in terms of atmospheric pressure, temperature cycles and UV radiation dose. The bacterial cells, contained into dedicated capsules, will be exposed to thermal cycles simulating diurnal and seasonal Martian cycles. The metabolism of the different biological samples will be analysed at different phases of the experiment, to study their survival and eventual activity of protein synthesis (mortality, mutations and capability of DNA repairing). We describe the experimental facility and provide the perspectives of the biological experiments we will perform in order to provide hints on the possibility of life on Mars either autochthonous or imported from Earth.