Objective: To determine the prevalence and the characteristics of Mycoplasma pneumoniae-related community-acquired pneumonia (CAP) and parapneumonic pleural effusion (PPE) in children and adolescents. Methods: This was a retrospective observational study involving 121 patients with CAP/PPE hospitalized in a tertiary referral hospital between 2000 and 2008, divided into six groups according to the etiologic agent (G1 to G6, respectively): M. pneumoniae with or without co-infection, in 44 patients (group 1); etiologic agents other than M. pneumoniae, in 77 (group 2); M. pneumoniae without co-infection, in 34 (group 3); Streptococcus pneumoniae, in 36 (group 4); Staphylococcus aureus, in 31 (group 5); and M. pneumoniae/S. pneumoniae co-infection, in 9 (group 6). Results: In comparison with group 2, group 1 showed higher frequencies of females, dry cough, and previous use of beta-lactam antibiotics; longer duration of symptoms prior to admission; and lower frequencies of use of mechanical ventilation and chest tube drainage. In comparison with groups 4 and 5, group 3 showed higher frequencies of previous use of beta-lactam antibiotics and dry cough; longer duration of symptoms prior to admission; a lower frequency of use of chest tube drainage; a higher mean age and a lower frequency of nausea/vomiting (versus group 4 only); and a lower frequency of use of mechanical ventilation (versus group 5 only). M. pneumoniae/S. pneumoniae co-infection increased the duration of symptoms prior to admission. Conclusions: In this sample, the prevalence of M. pneumoniae-related CAP/PPE was 12.75%. Although the disease was milder than that caused by other microorganisms, its course was longer. Our data suggest that M. pneumoniae-related CAP/PPE in children and adolescents should be more thoroughly investigated in Brazil.

Keywords: Pleural effusion; Empyema, pleural; Pneumonia; Mycoplasma pneumoniae.

Mycobacterium tuberculosis is one of the most successful human pathogens. Highly virulent strains, which are more easily transmitted than are less virulent strains, elicit variable immune responses. We evaluated the Th1 responses (IFN-γ production) in healthy volunteers after stimulation with various strains. Our results show that the individuals with negative tuberculin skin test (TST) results were not necessarily naive to all of the strains tested, whereas individuals with positive TST results did not respond to all of the strains tested. Drug-resistant strains induced a lower mean level of IFN-γ production than did drug-sensitive strains. One possible practical application of this finding would be for the prediction of responses to treatment, in which it might be advantageous to have knowledge of the estimated IFN-γ production elicited by a specific isolated strain.

Keywords: Tuberculosis; Polymorphism, restriction fragment length; Mycobacterium tuberculosis; Immunity, cellular; Interferon-gamma.

Background: Surveys of patients diagnosed with mycobacteriosis, taken at the Laboratory of Mycobacteriology of the Hospital das Clínicas da Universidade Federal de Minas Gerais, have shown that lack of information concerning diagnosis prevented 42% from initiating treatment. Objective: To evaluate the profile of patients with mycobacterial infection attending the Hospital das Clínicas da Universidade Federal de Minas Gerais. To describe the follow up of those patients and compare it to the guidelines made by the National Program for the Control of Tuberculosis. Methods: The files of patients diagnosed with mycobacterium infection during 2002 were selected from the archives of the Laboratory of Mycobacteriology of the Hospital das Clínicas da Universidade Federal de Minas Gerais. An active search for these patients was carried out and follow-up exams were then performed. Results: Of the 66 patients selected, 62 (94%) were positive for Mycobacterium tuberculosis and 4 (6%) had nontuberculous mycobacteriosis. Another 4 (6%) had been transferred to other institutions. Of the remaining 58, 37 (63%) had been cured, 1 (2%) had refused treatment, 9 (16%) were not found and 11 (19%) had died. Of the 11 deaths, 7 (64%) had tested positive for HIV. Conclusion: Patients failed to receive treatment not due to lack of diagnosis, but to inadequate structure, low awareness levels of all parties, and lack of tuberculosis control organization at the hospital level. Due to the high number of HIV-positive patients, the number of patients cured was lower than that required by the National Health Ministry. Deaths were attributed to HIV infection and lack of knowledge about the disease. In order to identify and address the problems associated with clinical laboratory practice, laboratory professionals must work in concert with their clinical counterparts when carrying out operational research on tuberculosis.

Keywords: Tuberculosis/diagnosis. Mycobacterium infections/complications.