[Use of DNA probes labelled with radioisotopes in the mycobacteria laboratory]. / Utilidad de las sondas de ADN, marcadas con isótopos radiactivos en el laboratorio de micobacterias.

We have studied 540 mycobacterial strains isolated in Lowestein-Jensen medium and 133 samples of different pathologic products against commercialized 125I-DNA Mycobacterium tuberculosis complex, Mycobacterium avitum-intracellulare and Mycobacterium gordonae. The sensitivity, specificity and positive and negative predictive values against isolated strains was 100% for the 3 studied probes. The 125I-DNA probe specific for M. tuberculosis complex is studied in samples with positive bacciloscopy; statistic values vary according to the cutting point of the different percentages of hybridization: at 1.5% the sensitivity, specificity and predictive negative and positive values are 38.6%, 71.4%, 97.5%, and 9.4% respectively, while if the cutting point percentage is 3% these values are: 33.1%, 100%, 100%, and 7.8% respectively. We believe that with these probes the identification time is limited to time needed for the incubation of prime cultures, and in some cases it can be performed on the day the samples reach the laboratory.

[16 cases of infection by Cryptococcosis neoformans in patients with AIDS]. / Estudio de 16 casos de infección por Cryptococcus neoformans en pacientes con SIDA.

Sixteen patients with AIDS (6% of the total AIDS patients) who had infection by Cryptococcus neoformans were studied. Most of these patients (94%) had cryptococcal meningitis. Only 50% of the cases showed clinical manifestations of neurological involvement. Blood cultures and antigen level measurement were the diagnostic techniques with best results due to their high percentage of positivity. Sixty nine percent of patients survived the acute phase of the infection and only 3 of those who died in this period showed evidence of active infection patients by the fungus.

Long-term follow-up of native valve infective endocarditis.

Seventy-eight consecutive episodes of infective endocarditis on native valves have been prospectively treated and followed-up after discharge from 1975 to 1982 (mean follow-up period 31 months). Twenty one patients needed valvular replacement in the active phase of the disease. Overall mortality was 15 cases, 7 from the medical group and 8 from the surgical group. At last clinical control 21 from the 46 survivors of the medical group remained asymptomatic, 17 had needed valvular replacement, 5 had died 2 of congestive heart failure and 3 (addicts) were lost to follow-up. From the 13 survivors of the surgical group 8 remained asymptomatic with good prosthetic function, 4 had needed reoperation due to severe periprosthetic leak and 1 died suddenly during follow-up. Figures at the end of follow-up showed that 28% of the initial patients had died, 39% carried a valvular prosthesis and 28% remained asymptomatic. A retrospective analysis of factors predictive of poor prognosis has been carried out.

Late prosthetic valve endocarditis.

A report is given of 13 patients with late prosthetic valve endocarditis (1975-1982). Follow-up ranged from 1 to 8 years (mean 33 months). Causative organisms were streptococci in 8 cases, staphylococci in 2, and Cardiobacterium hominis in 1. Cultures were negative in 2. Surgical treatment in the acute phase was performed in 3 patients. At the latest clinical control, 3 patients had died and 10 patients were asymptomatic, 3 of them having required late operation. These fair results are attributable to the particular spectrum of causative organisms and to the proper timing of surgical treatment in the 3 patients operated during the acute phase.