M. Sigfrido Rangel-Frausto

Risk Factors for Candidal Bloodstream Infections in Surgical Intensive Care Unit Patients: The NEMIS Prospective Multicenter Study

To assess risk factors for development of candidal blood stream infections (CBSIs), a prospective cohort study was performed at 6 sites that involved all patients admitted to the surgical intensive care unit (SICU) for >48 h over a 2-year period. Among 4276 such patients, 42 CBSIs occurred (9.82 CBSIs per 1000 admissions). The overall incidence was 0.98 CBSIs per 1000 patient days and 1.42 per 1000 SICU days with a central venous catheter in place. In multivariate analysis, factors independently associated with increased risk of CBSI included prior surgery (relative risk [RR], 7.3), acute renal failure (RR, 4.2), receipt of parenteral nutrition (RR, 3.6), and, for patients who had undergone surgery, presence of a triple lumen catheter (RR, 5.4). Receipt of an antifungal agent was associated with decreased risk (RR, 0.3). Prospective clinical studies are needed to identify which antifungal agents are most protective and which high-risk patients will benefit from antifungal prophylaxis.

Tuberculosis en trabajadores de la salud: importancia de los programas de vigilancia y control

OBJETIVO: Describir los resultados de la vigilancia de tuberculosis en trabajadores de la salud en un centro hospitalario de tercer nivel. MATERIAL Y METODOS: Se revisaron los registros de vigilancia de trabajadores durante 1992-1998, analizando variables demograficas, laborales, antecedentes clinicos, asi como pruebas previas, prueba de la tuberculina (PPD), refuerzos y seguimiento. Como medida de asociacion se utilizo la razon de momios (RM) con su respectiva significancia y los intervalos de confianza; la comparacion entre diferentes subgrupos se realizo con la prueba ji², y se determino tiempo de conversion con analisis de Kaplan Meier. RESULTADOS: Se vigilaron 1 617 trabajadores, 68%, mujeres y 32%, hombres. La edad promedio fue 26.9±7.6 (15-68) anos. Del total, 30.5% eran enfermeras; 14.6%, medicos residentes, y 14.1%, internos. Un 65.8% provenia del Distrito Federal. El 71.6% tenia BCG, y 15.1%, PPD previo. El PPD al ingreso fue positivo en 39.6% de los casos; negativo, en el 48.3%, y sin lectura, en el 12.1% restante. Se aplicaron 483 refuerzos (booster) en aquellos inicialmente negativos, y se encontraron 49 positivos. Se vigilo la conversion a PPD+ por aplicaciones periodicas en 231 trabajadores, y se encontro dicha conversion en 100 de ellos (43.3%). El tiempo promedio para detectar la conversion fue de 22.8±12.4 meses. La tasa de conversion a los 12 meses fue de 20%. Unicamente 50 trabajadores (50%) recibieron y aceptaron profilaxis con isoniazida. CONCLUSIONES: Un alto porcentaje de trabajadores son PPD+ al ingreso. Los refuerzos detectan 10% mas de casos. La tasa de conversion enfatiza la necesidad de organizar estos programas en Mexico.

Bloodborne viral infections in patients attending an emergency room in Mexico City: estimate of seroconversion probability in healthcare workers after an occupational exposure.

The frequency of hepatitis C (HCV), hepatitis B (HBV), human immunodeficiency virus (HIV), and human T-cell lymphotropic virus (HTLV) I/II was determined in the emergency room of a teaching hospital. Of 909 patients, 19% had at least one infection; 7.8% had HCV, 6.9% HBV, 3.3% HIV, and 2.8% HTLV I/II. The probability that a healthcare worker would have an accident with an infected patient and seroconvert was 4.99 to 24.9 per 100,000 venipunctures for HBV, 5.6 to 8.4 for HCV, and 0.12-0.16 for HIV in our emergency room.

Tuberculosis and tuberculin quality: best intentions, misleading results.

OBJECTIVE To compare the performance of three purified protein derivative (PPD) formulations: Tubersol (Connaught); RT23, Statens Serum Institut (SSI); and RT23, Mexico, tested in Mexican populations at low and high risk for tuberculosis (TB). DESIGN A double-blinded clinical trial. SETTING A university hospital in Mexico City. PARTICIPANTS The low-risk population was first or second-year medical students with no patient contact; the high-risk population was healthcare workers at a university hospital. METHODS Each of the study subjects received the three different PPD preparations. Risk factors for TB, including age, gender, occupation, bacille Calmette-Guérin (BCG) status, and TB exposure, were recorded. A 0.1-mL aliquot of each preparation was injected in the left and right forearms of volunteers using the Mantoux technique. Blind readings were done 48 to 72 hours later. Sensitivity and specificity were calculated at 10 mm of induration using Tubersol as the reference standard. The SSI tested the potency of the different PPD preparations in previously sensitized guinea pigs. RESULTS The low-risk population had a prevalence of positive PPD of 26%. In the low-risk population, RT23 prepared in Mexico, compared to the 5 TU of Tubersol, had a sensitivity of 51%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 86%. The RT23 prepared at the SSI had a sensitivity of 69%, a specificity of 99%, a positive predictive value of 95%, and a negative predictive value of 90%. In the high-risk population, the prevalence of positive PPD was 57%. The RT23 prepared in Mexico had a sensitivity of 33%, a specificity of 100%, and a positive predictive value of 53%; the RT23 prepared at the SSI had a sensitivity of 91%, a specificity of 98%, a positive predictive value of 98%, and a negative predictive value of 89%. RT23 used in Mexico had a potency of only 23% of that of the control. There was no statistical association among those with a positive PPD, irrespective of previous BCG vaccination (relative risk, 0.97; 95% confidence interval, 0.76-1.3;P=.78). CONCLUSIONS Healthcare workers had twice the prevalence of positive PPD compared to medical students. RT23 prepared in Mexico had a low sensitivity in both populations compared to 5 TU of Tubersol and RT23 prepared at the SSI. Previous BCG vaccination did not correlate with a positive PPD. Low potency of the RT23 preparation in Mexico was confirmed in guinea pigs. Best intentions in a TB program are not enough if they are not followed by high-quality control.

Clinical Manifestations and Survival Trends During the First 12 Years of the AIDS Epidemic in Mexico

BACKGROUND Our objective was to evaluate survival trends (1984-1995), the prevalence of AIDS-defining conditions, and the role of treatment with zidovudine and/or prophylaxis with trimethoprim-sulfamethoxazole (TMP-SMX) in survival following AIDS diagnosis. METHODS We reviewed the clinical charts and postmortem studies of all patients admitted to the HIV Clinic from 1984-1995. Three groups were identified according to the following dates of HIV diagnosis: 1) 1984-1988; 2) 1989-1992, and 3) 1993-1995. RESULTS We studied 909 charts. During the study period, 744 (81.6%) patients developed AIDS. Median survival increased from 11.7 months in group 1 to 15.4 and 17.5 months in groups 2 and 3, respectively (p <0.05). We observed the following important changes in the frequency of AIDS-defining conditions over the study period: Pneumocystis carinii pneumonia (PCP) decreased from 24.8 to 17 and 14% in groups 1, 2, and 3, respectively, (p = 0.008), and Kaposis sarcoma (KS), from 31.1 to 10.5 and 13.5% (p <0.001). On the other hand, there was an increase in cytomegalovirus disease with 12.4, 20.4, and 18.6% (p = 0.04) and wasting syndrome with 36, 45, and 57% (p <0.001). In the proportional hazard model for death, zidovudine or TMP-SMX use was associated with a protective effect. CONCLUSIONS Survival is improving among patients with HIV infection at our institution. The prevalence of AIDS-defining conditions has changed over the last 12 years. There has been a diminution of PCP and KS, whereas cases of CMV disease and wasting syndrome increased.

Malaria Protection of the International Traveler

Thorough counseling with emphasis on the importance of mosquito bite avoidance, as well as on compliance with prophylactic antimalarial regimens, remains an important task for the physician preparing a patient for international travel. Chloroquine continues to be the drug of choice for prophylaxis in areas not reporting chloroquine resistance. Otherwise, mefloquine is the first-line agent. Under special circumstances, alternatives to mefloquine can be employed and include doxycycline or proguanil plus chloroquine.