Evaluation of adenosine deaminase activity in the Mycobacterium tuberculosis culture supernatants.

BACKGROUND: Adenosine deaminase (ADA) catalyzes hydrolytic and irreversible deamination of deoxyadenosine into deoxyinosine and of adenosine into inosine, and is related to lymphocytic proliferation and differentiation. The measurement of ADA activity in body fluids is a useful tool in the evaluation of mycobacterial infections. Elevated ADA activity has been found in pleural effusions of patients with pleural tuberculosis relative to those from patients with nontuberculous pleural diseases, and is mainly associated with cellular host factors such as monocyte-macrophages or lymphocytes. In contrast, there is little information about ADA activity measurement in mycobacteria culture supernatants. METHODS: We evaluated ADA activity as described by Giusti in the culture supernatants of eight Mycobacterium tuberculosis isolates. RESULTS: Mycobacteria culture supernatants did not display any ADA activity. CONCLUSIONS: This result supports the notion that Mycobacterium tuberculosis is not the source of ADA activity. However, increased ADA activity in biological fluids from tuberculosis patients might be due to the interaction of the mycobacterium with host factors.

[Diagnostic usefulness of bronchoalveolar lavage in nosocomial pneumonia associated with mechanical ventilation in patients undergoing antibiotic treatment]. / Utilidad diagnóstica del lavado broncoalveolar en la neumonía nosocomial asociada con ventilación mecánica en pacientes bajo tratamiento antibiótico.

We evaluated the diagnostic utility of the colony forming units (CFU) count in bronchoalveolar lavage (BAL) cultures from patients with nosocomial pneumonia associated with mechanical ventilation (PAMV) and treatment with systemic antibiotics. Cultures with greater than 10(4) CFU/ml were considered positive, while the absence of cultures was considered negative. Cultures with < or = 10(3) CFU/ml were classified as contaminated. The gold standard was defined by clinical, bacteriological, and histological criteria. We studied 12 patients suspected of having PAMV, and six controls who had no evidence of pneumonia or infection of any kind. Positive cultures were found in all patients suspected of having PAVM, while all controls had negative cultures. One patient was eliminated because we were unable to corroborate the final diagnosis. Using the gold standard, nine patients had PAVM, and eight did not have PAVM. The sensitivity of the test was 100%, and the specificity was 75%, while the positive predictive value was 88%, and the negative predictive value 100%. We conclude that the CFU count in BAL cultures is a useful method for the diagnosis of PAMV in patients treated with systemic antibiotics.

[Tuberculosis associated with HIV infection]. / Tuberculosis asociada a infección por el virus VIH.

Tuberculosis and human immunodeficiency virus (HIV) infection are two important linked public health problems in the world of today. Tuberculosis in HIV infected patients is frequently atypical in its clinical and radiological findings and commonly has an extrapulmonary dissemination. Atypical mycobacteriosis have also been reported in patients with HIV infection. We review here all the patients admitted from 1986 to 1991 with definitive diagnosis of tuberculosis and HIV infection at the National Institute of Respiratory Diseases in Mexico City. Out of 220 patients with HIV infection and pulmonary complications, 19 had proven tuberculosis. Their mean age was 34 +/- 8 years and seven were homosexual males. In 16 patients (84%), respiratory symptoms (cough with sputum) and fever were the first manifestations of the HIV infection. Only two patients had the typical cavitary lesions but also coexisting with miliary tuberculosis. The rest had several types of non cavitated pulmonary opacities or other thoracic or pleural alterations. Eleven patients (58%) had, in addition, extrapulmonary tuberculosis. Mycobacterium tuberculosis was cultured in 11 of 12 patients but no atypical mycobacteria were isolated. Only seven of the 19 patients completed at least six months of treatment and two of them relapsed. Three patients died in their first admission; the rest were lost in the follow up. Our results show that the clinical features of tuberculosis associated to HIV infection are similar to those described in other countries.

[Antibiotic susceptibility to microorganisms isolated in blood cultures of patients an the Ignacio Chavez National Institute of Cardiology]. / Susceptibilidad a antimicrobianos de microorganismos aislados en hemocultivos de pacientes del Instituto Nacional de Cardiología Ignacio Chávez.

A microdilution method was utilized for determining susceptibility to several antimicrobial agents in 142 bacterial blood culture isolates obtained during a one year period. Associated clinical features were also identified. Three cases of polymicrobial bacteriemia were found. Endocarditis was the most frequent source of bacteriemia (28.5%) and the viridans streptococci were the most frequently isolated microorganism (53%). Surprisingly, half of the bacteriemic episodes corresponded to a nosocomial infection most of which were due to staphylococci (25%) and Enterobacter sp (22%). Viridans streptococci group were 61.5% resistant to penicillin (MIC > 0.12 micrograms/mL). These strains also showed a 31% resistance to ceftriaxone (MIC > 8 micrograms/mL). The staphylococcal strains showed a 19% resistance to oxacillin; this resistance occurred for coagulase negative staphylococcis in 32% (6/19) and for S. aureus in 9% (2/22). All Gram-positive microorganisms were susceptible to vancomycin. The enterobacteria group were susceptible to most antimicrobial agents; nevertheless this group showed a 45% resistance to amikacin. In contrast, the non enterobacteria group were resistant to most of the antimicrobial agents tested except to imipenem, ceftazidime and ciprofloxacin. When comparing susceptibility longitudinally, no significative changes were identified, but a significant increase was found in MIC50-90 to amikacin and cephalothin when testing S. aureus, and cefoperazone in the non enterobacteria group.

Evaluacion clinica de amikacina el el tratamiento de infecciones causadas por bacilos gramnegativos. / Clinical evaluation of amikacin in the treatment of infections caused by gram-negative bacilli

Fue evaluada en 20 pacientes la eficacia y seguridad de la amikacina en el tratamiento de pacientes con infecciones causadas por bacilos gramnegativos. Se utilizo una dosis de 15 mg/kg/dia administrada por via endovenosa a 9 pacientes y por via muscular a 11, en dos dosis divididas con intervalos de 12 horas. La duracion del tratamiento fue de 8 a 10 dias (promedio 9 dias). De los 20 pacientes, 5 tuvieron neumonia, 4 infeccion del tracto urinario, 3 infeccion pelvica aguda, 5 septicemias, 1 infeccion quirurgica, 1 absceso de pared abdominal y 1 endocarditis. De los dieferentes sitios involucrados se logro aislar los siguientes organismos: E. coli 4, K. pneumoniae 4, Klebsiella-Enterobacter 8, P. aeruginosa 4, S. marcescens 1, P. mirabilis 2, Enterococo 1 y A. anitratus 1. La respuesta al tratamiento con amikacina fue excelente; no se observaron efectos colaterales serios