Prevalencia de Bartonella henselae en donantes de sangre y riesgo de transmisión sanguínea en Chile / Prevalence of Bartonella henselae in blood donors and risk of blood transmission in Chile

Resumen Introducción: Bartonella henselae es el agente causal de la enfermedad del arañazo del gato en personas inmunocompetentes y de la angiomatosis bacilar y peliosis hepatis en inmunocomprometidos. En Chile la prevalencia de anticuerpos contra B. henselae en niños y adolescentes sanos es de 13,3%, en personas con riesgo ocupacional 60,5% y en gatos 85,6%. No existen datos publicados respecto de la seroprevalencia en donantes de sangre en nuestro país, por lo que determinar si B. henselae se encuentra presente en la sangre de los donantes al momento de la donación es muy importante, ya que este microorganismo puede sobrevivir hasta 35 días en los eritrocitos almacenados en banco de sangre a 4 °C. Objetivo: Determinar la prevalencia de B. henselae en donantes de sangre. Metodología: Se analizaron 140 muestras de sangre de donantes, para detectar la presencia de B. henselae, utilizando la técnica de la reacción de polimerasa en cadena (RPC). Resultados: Se obtuvo 13,6% de los donantes de sangre con RPC positiva para la B. henselae. La secuencia de los fragmentos amplificados presentó una identidad por sobre 98% con respecto a secuencias de B. henselae de referencia. Conclusión: El riesgo de transmisión sanguínea debiera ser considerado en un país con alta seroprevalencia de infección por B. henselae.

Background: Bartonella henselae is the causal agent of cat scratch disease in immunocompetent persons and bacterial angiomatosis in immunocompromised patients. In Chile, the prevalence of antibodies against B. henselae in healthy children and adolescents is 13.3%, in persons with occupational risk 60.5%, and in cats 85.6%. There are no published data regarding the seroprevalence in blood donors in our country, so determining if B. henselae is present in the blood of donors at the time of donation is very important, since this microorganism can survive up to 35 days in the red blood cells stored in a blood bank at 4 °C. Objective: To determine the prevalence of B. henselae in blood donors. Methodology: 140 donor blood samples were analyzed to detect the presence of B. henselae, using the polymerase chain reaction technique. Results: 13.6% of the blood donors with positive polymerase chain reaction for B. henselae were obtained. The sequence of the amplified fragments showed an identity of over 98% with respect to B. henselae reference sequences. Conclusion: The risk of blood transmission is due to a country with high B. henselae infection.

stg fimbrial operon from S. Typhi STH2370 contributes to association and cell disruption of epithelial and macrophage-like cells

BACKGROUND: Salmonella enterica serovar Typhi (S. Typhi) stg operon, encoding a chaperone/usher fimbria (CU), contributes to an increased adherence to human epithelial cells. However, one report suggests that the presence of the Stg fimbria impairs the monocyte-bacteria association, as deduced by the lower level of invasion to macrophage-like cells observed when the stg fimbrial cluster was overexpressed. Nevertheless, since other CU fimbrial structures increase the entry of S. Typhi into macrophages, and considering that transcriptomic analyses revealed that stg operon is indeed expressed in macrophages, we reassessed the role of the stg operon in the interaction between S. Typhi strain STH2370 and human cells, including macrophage-like cells and mononuclear cells directly taken from human peripheral blood. RESULTS: We compared S. Typhi STH2370 WT, a Chilean clinical strain, and the S. Typhi STH2370 Astg mutant with respect to association and invasion using epithelial and macrophage-like cells. We observed that deletion of stg operon reduced the association and invasion of S. Typhi, in both cellular types. The presence of the cloned stg operon restored the WT phenotype in all the cases. Moreover, we compared Salmonella enterica sv. Typhimurium 14028s (S. Typhimurium, a serovar lacking stg operon) and S. Typhimurium heterologously expressing S. Typhi stg. We found that the latter presents an increased cell disruption of polarized epithelial cells and an increased association in both epithelial and macrophage-like cells. CONCLUSIONS: S. Typhi stg operon encodes a functional adhesin that participates in the interaction bacteria-eukary-otic cells, including epithelial cells and macrophages-like cells. The phenotypes associated to stg operon include increased association and consequent invasion in bacteria-eukaryotic cells, and cell disruption.