Legionelosis: Recomendaciones para la prevención, la vigilancia epidemiológica y el control de casos y brotes / Legionellosis: Recommendations for prevention, epidemiological surveillance and control of cases and outbreaks

La enfermedad de los legionarios es un importante problema de salud pública particularmente por su frecuente presentación en forma de brotes, tanto comunitarios como nosocomiales, y por su letalidad, especialmente en personas de edad avanzada o con otras enfermedades. La notificación oportuna de casos y/o brotes de enfermedad y la investigación epidemiológica permiten la identificación de la/s fuentes de exposición y la adopción de medidas de prevención y control adecuadas. Las infecciones por Legionella son más frecuentes entre adultos mayores de 50 años, hombres, fumadores y huéspedes inmunocomprometidos o con ciertas enfermedades crónicas subyacentes. La infección en niñas/os es rara, con ≤ 1% de los casos de neumonía causada por Legionella, y puede ser asintomática o leve y no detectada. La Legionella puede multiplicarse si el agua no es tratada de manera adecuada o si los sistemas de agua no son mantenidos adecuadamente.

COVID-19 among Chronic Dialysis Patients after First Year of Pandemic, Argentina.

We performed a descriptive study to characterize effects from COVID-19 among chronic dialysis patients compared with the general population in Argentina during March 2020-February 2021. COVID-19 case-fatality rate of chronic dialysis patients was 10 times the national rate; the age-standardized mortality ratio was 6.8 (95% CI 6.3-7.3).

Molecular detection of circulating tyrosinase mRNA: optimization in a preclinical xenograft mouse melanoma model and further evaluation in samples from advanced melanoma patients.

We designed high-affinity primers for the mRNA sequence of human tyrosinase to test the value of molecular detection of circulating melanoma cells by reverse transcription-polymerase chain reaction (RT-PCR). The optimization process included in vitro settings and in vivo studies in a xenograft mouse model. We detected tyrosinase expression with at least 40 pg and 1.5 pg of total RNA extracted from cultured SKmel human melanoma cells, using a first round of PCR amplification and nested PCR, respectively. Human tyrosinase expression was found in the blood of nude mice bearing subcutaneous SKmel tumors, and the expression bands were stronger after manipulation of the tumor mass. We also examined the fate of circulating melanoma cells in the present melanoma model. Tyrosinase expression declined in blood 6 h after a direct intravenous injection of SKmel cells. A preliminary study in human blood samples demonstrated a baseline positive tyrosinase determination in 64% (16/25) of advanced melanoma patients using the RT-PCR nested assay. Baseline tyrosinase expression was significantly associated with disease progression after 12 months, and sequential determination during follow-up of the remaining disease-free patients showed a progressive increase of negative results.