RESUMEN
Rare cases of extrapulmonary involvement in Legionella spp. infections have been described, mostly in immunocompromised adults. We report a case of a 2-month old male with reticular dysgenesis variant of severe combined immune deficiency with multiple liver lesions. Core-needle biopsies of one liver lesion demonstrated Gram-negative bacilli and a broad-spectrum polymerase chain reaction assay detected Legionella pneumophila.
Asunto(s)
Hepatitis/etiología , Hepatitis/patología , Legionella pneumophila/aislamiento & purificación , Enfermedad de los Legionarios/diagnóstico , Enfermedad de los Legionarios/patología , Inmunodeficiencia Combinada Grave/complicaciones , Inmunodeficiencia Combinada Grave/patología , Biopsia , Histocitoquímica , Humanos , Lactante , Masculino , Microscopía , Reacción en Cadena de la PolimerasaRESUMEN
For a 13-month period, all respiratory tract secretions submitted for routine bacteriology from a large hospital complex were cultured for legionella, irrespective of clinical diagnosis and laboratory requests. Ten cases of legionellosis were detected in this manner, three of which met a strict epidemiological definition of hospital-acquired. Therefore, the 16 warm-water systems of the hospitals, spread out over two locations, were examined for the presence of legionella. Legionella pneumophila was found in 15 warm water systems, with a distinct pattern of serogroups between the two locations. Legionella of the same serogroups as those isolated from patients were present in each hospital water supply. The isolates were further typed by monoclonal antibodies and by genomic macrorestriction analysis. Similarity between clinical and environmental isolates was found in seven cases. In these cases, acquisition from the hospital water supply appears very likely. The strains of the remaining three patients did not match those in hospital water, suggesting that community-acquired legionellosis was occurring as well. This study suggests that routinely culturing respiratory tract secretions of pneumonia patients for legionella can help diagnose unsuspected cases of legionellosis. Typing legionella strains beyond the serogroup level with tools such as macrorestriction analysis is useful to define sources of infection, which can then be targeted for control measures.
Asunto(s)
Control de Infecciones , Legionella pneumophila/aislamiento & purificación , Enfermedad de los Legionarios/diagnóstico , Abastecimiento de Agua , Adulto , Anciano , Infecciones Comunitarias Adquiridas/diagnóstico , Infecciones Comunitarias Adquiridas/microbiología , Infección Hospitalaria/diagnóstico , Infección Hospitalaria/microbiología , Electroforesis en Gel de Campo Pulsado , Femenino , Alemania , Humanos , Legionella pneumophila/clasificación , Legionella pneumophila/genética , Enfermedad de los Legionarios/microbiología , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Esputo/microbiología , Tráquea/microbiología , Microbiología del AguaRESUMEN
Candida albicans and Saccharomyces cerevisiae switch from a yeast to a filamentous form. In Saccharomyces, this switch is controlled by two regulatory proteins, Ste12p and Phd1p. Single-mutant strains, ste12/ste12 or phd1/phd1, are partially defective, whereas the ste12/ste12 phd1/phd1 double mutant is completely defective in filamentous growth and is noninvasive. The equivalent cph1/cph1 efg1/efg1 double mutant in Candida (Cph1p is the Ste12p homolog and Efg1p is the Phd1p homolog) is also defective in filamentous growth, unable to form hyphae or pseudohyphae in response to many stimuli, including serum or macrophages. This Candida cph1/cph1 efg1/efg1 double mutant, locked in the yeast form, is avirulent in a mouse model.
Asunto(s)
Candida albicans/genética , Candida albicans/patogenicidad , Proteínas de Saccharomyces cerevisiae , Animales , Candida albicans/crecimiento & desarrollo , Células Cultivadas , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Eliminación de Gen , Macrófagos Peritoneales/citología , Macrófagos Peritoneales/microbiología , Ratones , Ratones Endogámicos , Mutagénesis/fisiología , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crecimiento & desarrollo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , VirulenciaRESUMEN
The Candida albicans genes, CST20 and HST7, were cloned by their ability to suppress the mating defects of Saccharomyces cerevisiae mutants in the ste20 and ste7 genes, which code for elements of the mating mitogenactivated protein (MAP) kinase pathway. These Candida genes are both structural and functional homologs of the cognate Saccharomyces genes. The pattern of suppression in Saccharomyces is related to their presumptive position in the MAP kinase cascade. Null alleles of these genes were constructed in Candida. The Candida homozygous null mutants are defective in hyphal formation on some media, but are still induced to form hyphae by serum, showing that serum induction of hyphae is independent of the MAP kinase cascade. The Candida heterozygotes CST20/cst20 and HST7/hst7 are also defective in hyphal formation. This lack of dominance of the wild-type allele suggests that gene dosage is important in Candida.