Serological response to COVID-19 pneumonia and increasing severity over 18 months in a prospective cohort of hospitalized patients.

In this study, we present an 18-month serological follow-up of 294 patients with COVID-19 pneumonia. The aim was to assess the dynamics of serological response and its correlation with clinical worsening, as well as to describe clinical worsening determinants. Results of the study showed an early immunoglobulin M response, which clearly diminished starting at 4 months, but nonetheless, a small group of patients remained positive. As for immunoglobulin G, levels were higher up to 6 months in patients who presented clinical worsening during hospitalization. High titers of the immunoglobulin were maintained in all patients during follow-up, which would indicate that humoral immunity due to infection is long-lasting. Male sex, presence of myalgias and extensive radiological affectation were significantly correlated with clinical worsening.

Pruebas serológicas falsamente positivas en malaria / False-positive serological tests in malaria

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A randomized clinical trial comparing nelfinavir or nevirapine associated to zidovudine/lamivudine in HIV-infected naive patients (the Combine Study).

BACKGROUND: Non-nucleoside reverse transcriptase inhibitor-containing regimens may be a valid alternative to protease inhibitor-containing regimens for initial antiretroviral therapy, but to date few studies comparing these two strategies have been performed. OBJECTIVE: To evaluate the efficacy and safety of nelfinavir or nevirapine associated to zidovudine/lamivudine in HIV-infected naive patients. DESIGN: Randomized, open-label, multicentre trial. SETTING: Twelve centres in Spain (9) and Argentina (3). PATIENTS: One hundred and forty-two HIV-infected naive patients without AIDS. INTERVENTIONS: Patients received combivir (zidovudine 300 mg/lamivudine 150 mg, twice-daily) plus either nelfinavir (1250 mg) twice-daily (zidovudine/lamivudine/nelfinavir, n=70) or nevirapine (200 mg) twice-daily (zidovudine/lamivudine/nevirapine, n=72), and were followed for 12 months. The primary endpoint was the proportion of patients with a plasma HIV-1 RNA (pVL) of less than 200 copies/ml by PCR at 12 months. pVL of less than 20 copies/ml (PCR), changes in CD4 counts, clinical progression and adverse events were also evaluated. Efficacy was assessed using intent-to-treat (ITT) (missing=failure) and on-treatment analysis. RESULTS: At 12 months in the ITT analysis the proportion of patients with pVL below 200 copies/ml was 60% (95% CI 48.5-71.5) in the zidovudine/lamivudine/nelfinavir arm and 75% (95% CI 65-85) in the zidovudine/lamivudine/nevirapine arm (P=0.06), and the proportion below 20 copies/ml was 50% (95% CI 38.3-61.7) and 65% (95% CI 54.2-76.2), respectively (P=0.06). No differences were found when comparing the subgroup of patients with baseline pVL of more than 100,000 copies/ml. A gain of +173 and +162 CD4 cells/mm3, respectively, was observed. Zidovudine/lamivudine/nelfinavir was discontinued in 21% of patients, and zidovudine/lamivudine/nevirapine in 25%, due to toxicity (P>0.2). CONCLUSIONS: Our results suggest that zidovudine/lamivudine/nevirapine is at least as effective as zidovudine/lamivudine/nelfinavir as first-line therapy for HIV disease.

Evaluación de cuatro métodos rápidos para la investigación de la capacidad toxigénica de las cepas de clostridium difficile aisladas en un medio selectivo / Evaluation of four rapid methods for the investigation of the toxigenic capacity of Clostridium difficile strains isolated in a selective medium

Fundamento: El diagnóstico por cultivo de la enfermedad asociada a Clostridium difficile requiere confirmar la capacidad toxigénica de los aislamientos. La técnica de referencia es la detección de la citotoxina por cultivo celular tras el crecimiento del microorganismo durante 3-5 días en medio líquido, implicando una demora en el diagnóstico final. En este estudio, se comparan de forma retrospectiva 4 métodos rápidos para la investigación de la toxigenicidad in vitro de las cepas de C. difficile. Métodos: Se han utilizado 106 aislamientos clínicos de C. difficile (72 toxigénicos y 34 no toxigénicos), y 16 de otras especies de Clostridium. Los cuatro métodos se llevaron a cabo directamente a partir de las colonias aisladas en medio sólido. Los métodos evaluados fueron: a) detección directa de la citotoxina; b) dos técnicas de amplificación por reacción en cadena de la polimerasa (PCR) de los genes codificantes de toxina A y B, respectivamente, y c) detección de la toxina A por enzimoinmunoanálisis (VIDAS CDA2). En todos ellos, el tiempo total de procesamiento fue inferior al de una jornada laboral. Resultados: Sólo las 72 cepas de C. difficile toxigénicas mostraron resultados positivos por cultivo celular y por las técnicas de PCR (sensibilidad y especificidad del 100 por ciento). En cuanto a la técnica de VIDAS, hubo 14 resultados falsos negativos entre las 49 cepas de C. difficile toxigénicas investigadas, aunque todas estas cepas fueron positivas en pruebas repetidas. Conclusiones: Aunque todos los métodos fueron eficaces, la detección de citotoxina directa de colonias es una técnica sencilla, rápida y adecuada para aquellos laboratorios que dispongan de cultivos celulares (AU)