ABSTRACT
La reacción de Widal es un test basado en el principio de aglutinación antígeno-anticuerpo, donde se determina la presencia de anticuerpos contra el antígeno O y H de la Salmonella typhi para el serodiagnóstico de fiebre tifoidea, sin embargo debido a su falta de especificidad, debe ser interpretado en el contexto clínico del paciente. Para considerar el diagnóstico de fiebre tifoidea con un titulo Anti-O y Anti-H aislado, se debe conocer su prevalencia en una determinada comunidad, en términos generales, se acepta títulos anti-O y anti-H > o = 1: 160-200 y > o = 1: 50-100 en zonas endémicas y no endémicas, respectivamente.
Subject(s)
Typhoid Fever/diagnosis , Typhoid Fever/microbiology , Salmonella typhi/isolation & purification , Salmonella typhi/ultrastructure , Clinical Laboratory Techniques , Antigen-Antibody Reactions , Agglutination TestsSubject(s)
Salmonella paratyphi A/pathogenicity , Salmonella paratyphi A/ultrastructure , Salmonella paratyphi B/pathogenicity , Salmonella paratyphi B/ultrastructure , Salmonella paratyphi C/pathogenicity , Salmonella paratyphi C/ultrastructure , Salmonella typhi/classification , Salmonella typhi/pathogenicity , Salmonella typhi/ultrastructure , Typhoid Fever , Diagnosis, Differential , Paratyphoid Fever , Typhoid-Paratyphoid VaccinesABSTRACT
Salmonella typhi is a facultative intracellular human specific pathogen. Both immunocompetent and immunodeficient mice are resistant to S. typhi. However, when they are infected with S. typhi suspended in mucin, the bacteria become pathogenic and infect peritoneal phagocytic cells. The LD50 for mice was 10(5) bacteria suspended in 5 percent mucin; mouse survival was approximately 48 hours after injection. A high number of bacteria was recovered from peritoneal cells; transmission electron microscopy disclosed a large number of vesicles filled with S. typhi cells in peritoneal cells from infected animals. The addition of mucin to cultures of the reticuloendothelial cell line J774.3 also allowed invasion of the mammalian cells with S. typhi. These data indicate that mucin allows intracellular survival of S. typhi