PREVALENCE OF MYCOBACTERIUM TUBERCULOSIS AMONG PROFESSIONALS IN A UNIVERSITY HOSPITAL , MATO GROSSO DO SUL , 2004

Disponible en castellano/Disponível em língua portuguesa SciELO Brasil www.scielo.br/rlae 1 RN, MS, Infectious Diseases Unit, e-mail: sandraleone@nin.com.br; 2 PhD Professor, e-mail: mrhoner@terra.com.br; 3 Adjunct Professor, e-mail: anapaniago@terra.com.br, e7aguiar@uol.com.br, rivaldo_venancio@brturbo.com.br. Mato Grosso do Sul Federal University, Brazil Rev Latino-am Enfermagem 2007 novembro-dezembro; 15(6):1120-4 www.eerp.usp.br/rlae Artigo Original


INTRODUCTION
Tuberculosis infection affects one third of the planet's population and was considered a world emergency by the World Health Organization (WHO) in 1993.According to present estimates, there exist around eight million cases and two million deaths due to tuberculosis, circumscribed to 22 countries.Brazil occupies the 15 th place, notifying around 80 to 90 thousand new cases per year, corresponding to the th reason for hospitalization in the Single Health System and the 4 th cause of mortality due to infectious disease (1)(2) .
Besides the increased incidence of tuberculosis in the general population, a change is occurring in the illness' natural history in special population groups, particularly in hospital environments, where a high prevalence of individuals carrying comorbidities is found, such as infection by the Human Immunodeficiency Virus (HIV), cancer and diabetes mellitus.These comorbidities might favor the increase of non-isolated hospital time until the infection is diagnosed, thus propagating the microorganism within these environments .
Several studies indicate a major risk among professionals who act in health care institutions and alert that factors like service time, professional category and respiratory protection are relevant in transmission.The diagnosis and lab corroboration delay, as well as the precariousness of infrastructural conditions, the inexistence of isolation beds and a work process that involves a long work period, culminating in double employment, stress and often work overload, are also mentioned as related factors (2)(3)(4) .
In some regions, a large number of tuberculosis cases can be observed, attended and diagnosed in hospital environments, as the patients usually turn to these places for diagnosis and treatment, increasing the probability of resistant TB cases, and thus justifying tuberculin screening among health professionals in hospital units (1,5) .

Place of Study
The study was carried out at the UFMS (HU/ UFMS) University Hospital, a large hospital of high complexity, which offers a care program for patients with tuberculosis diagnoses and is a referral institution in the state for infectious diseases like HIV/AIDS.

Study design
The study was performed between 04/01 and 09/30/2004 and the population consisted of HU/UFMS workers, who had direct or indirect contact with patients during the hospitalization process in the intrahospital environment, or with their secretions in the lab environment.
Selected civil servants who accepted to take part in the study were included, after having received verbal information on the purposes and methodology of the research.This acceptance was given in writing.
They completed a standard form for data collection on the study variables and were submitted to the tuberculin test for the first time.When negative, however, they were submitted to a second application within the next 1 -3 weeks for booster effect analysis.
Based on epidemiologic studies, which estimate a frequency of 25%, a prevalence sample estimate of 30% was used for calculation purposes (4) .
The hospital employed 1218 civil servants.Workers who presented a history of tuberculosis, who had used tuberculostatic agents in the past, and/or were passing through immunosuppressant therapy, as well as those who did not agree in participating after reading the free and informed consent term, were excluded.
The Mantoux technique was used for tuberculin testing.Appropriate syringes (1 ml) and 13X4.5 G discarding needles for intradermal administration of 0.1 ml PPD (purified protein derivate) in the left interior forearm of each professional.After 72 hours, the author, who had been trained and qualified for appliance and lecture at a Tuberculosis Reference Center, performed a lecture for evaluation of papule formation with well delimited borders (2,6) .
Pparticipants whose tuberculin test presented an induration e" 10 mm were considered as infected, evaluated within 72 hours, and the booster effect was tested after 1-3 weeks (2,7) .

Ethical Aspects
The present study was approved by UFMS' Ethics Committee for research involving human beings.

RESULTS
Tuberculosis infection prevalence among the 194 participants was 38.7%.No statistically significant difference was observed among the activity groups.
The global and activity tuberculin test positivity among the 194 participants is shown in Table 1.Experts found a 2.57 times higher infection risk regarding professionals older than 46 years when compared to those between 26 and 45 years old.When comparing professionals with more or less than 20 years of activity, the infection risk got 21 times higher (8)   .
In a study performed at a general hospital in Montreal, Canada, 38.5% (196/522) were reactors.
At this hospital, circumstances like inadequate ventilation and diagnosis delay were identified as the main factors related to tuberculosis infection (8) .

Similar studies involving professionals at
Brazilian university hospitals found high percentages of strong reactors, with positivity rates ranging from 40.35 to 52.0% (6, 8)   .
It is known that frequent contact with patients with tuberculosis increases the risk of acquiring the infection.In order to evaluate this infection risk, a comparative study was performed between nursing professionals and factory employees.The results observed a strong reactor prevalence of 51.5% in the first group and 16.7% among factory employees, with an infection risk 3.15 times higher in the nursing professional group (7, 9-10) .
Significant factors for positive tuberculin test are related to male gender and work time of more than one year at the hospital.The risk would get higher after a year employment, suggesting that prevention should focus on persons at the start of their career, many of them not infected yet (8) .
Studies relate tuberculin test positivity with age, male gender and previous BCG vaccination.Male gender and work type and/or location were independent predicting factors for tuberculin test conversion among employees of a Brazilian university hospital (10)   .
Another study detected an increasing positivity rate (4.0%, 6.4%, 13.1%) among students of a Medical College in Campos, as well as increasing tuberculin test positivity according to professional activity time (11) .Moreover, an association was observed between positive tuberculin test and hospital activity time of more than five years, without relation to variables like education level and family income (12)(13) .
Tuberculin research found a 15.2% positivity upon admission and 23.2% after 15 years of work.These results suggest that, despite the age factor, occupational exposure presents a risk for acquiring the infection, and that preventive interventions are fundamental in the professionals' admission period (10)(11)13) .
Recent conversions and tuberculin rotation could be lower if worker protection measures were adopted in health care establishments (14)(15) .
There exists important evidence concerning nicotine addiction as a risk factor for pulmonary as well as intrapulmonary tuberculosis.The cough that smokers usually present is a bacillus spreading factor, as there exist studies associating passive exposure to cigarettes with the occurrence of active pulmonary tuberculosis in infected contact children (17) .
In the present study, when comparing exsmokers and non-smokers (132/194) to smokers (32/ 194), a statistically significant association was observed between the smoking habit and a positive tuberculin test result (p=0.01), with smokers presenting a 1.72 higher chance of reactivity (17) .

CONCLUSIONS
an outbreak research performed at a psychiatric clinic in Rio de Janeiro, between 2001 and 2002, 15 TB cases occurred among 374 interned patients and 4 cases among 200 other professionals who worked at the institution's first aid department.
Tuberculosis prevalence among health professionals is strongly related to the presence of patients with tuberculosis in the hospital environment, Prevalence of mycobacterium tuberculosis among professionals... Oliveira SMVL, Honner MR, Paniago AMM, Aguiar ESA, Cunha RV.Rev Latino-am Enfermagem 2007 novembro-dezembro; 15(6):1120-4 www.eerp.usp.br/rlaereflecting the epidemiologic reality of tuberculosis within the community.The implementation of administrative measures, among which the tuberculin test, are a priority when considering the increase in the total number of patients interned in hospital beds with tuberculosis, in association to HIV/AIDS or other immunosuppressant illnesses, as well as in the detection of resistant strains.Urgent discussions are needed within health care establishments, calling attention to the need for tuberculosis biosafety as a technical standard and tuberculin screening in the academic training period and in newly admitted health care personnel, besides the implementation of research lines regarding infection risk evaluation in health professionals, validating the adopted measures and its efficacy cost.It is also considered important to use different training strategies, always trying to find out the factors involved in non-adherence to respiratory protection strategies within health environments.

Table 1 -
Professional distribution per category,

Table 2 -
Professional distribution per gender and age,

Table 3 -
Subject distribution according to Cage, nicotine DISCUSSIONAmong the 194 participants, 65 (33.5%) were PPD reactors on the first test.The others (119) were submitted to a second test, ten of whom showed to