RESUMEN
Lactobacillus rhamnosus is a rare clinical pathogen. A case of bacteremia caused by L. rhamnosus in a kidney transplant recipient is described. Once considered only as a contaminant or a low-virulence organism, L. rhamnosus might be an opportunistic pathogen in immunocompromised patients. To our knowledge, this is the first report of primary bloodstream infection caused by L. rhamnosus in a kidney transplant recipient.
Asunto(s)
Bacteriemia/diagnóstico , Huésped Inmunocomprometido , Trasplante de Riñón , Lacticaseibacillus rhamnosus/aislamiento & purificación , Complicaciones Posoperatorias/diagnóstico , Adulto , Bacteriemia/inmunología , Femenino , Humanos , Complicaciones Posoperatorias/inmunologíaRESUMEN
This study assessed risk factors for 30-day mortality in 66 patients with carbapenem-resistant Acinetobacter baumannii (CRAB) infection or colonization during an outbreak in an intensive-care unit. Clinical and demographic characteristics were evaluated. The overall 30-day mortality was 47·0%. In the multivariate Cox regression model, septic shock [adjusted hazard ratio (aHR) 5·01, 95% confidence interval (CI) 2·32-10·01] and APACHE II score at onset of infection (aHR 1·11, 95% CI 1·04-1·18) were significantly associated with 30-day mortality. Administration of appropriate therapy was a protective factor, but it was not statistically significant (aHR 0·48, 95% CI 0·21-1·12). A sample of isolates tested (n=27) carried the blaOXA-23 gene. Severity of baseline condition and severity of infection presentation were major risk factors for mortality during the outbreak. Patients who received appropriate therapy tended to have lower mortality rates, although therapy was started late and dosage was suboptimal in most cases.
Asunto(s)
Infecciones por Acinetobacter/epidemiología , Infecciones por Acinetobacter/mortalidad , Acinetobacter baumannii/efectos de los fármacos , Carbapenémicos/farmacología , Brotes de Enfermedades , Resistencia betalactámica , APACHE , Infecciones por Acinetobacter/complicaciones , Infecciones por Acinetobacter/patología , Acinetobacter baumannii/aislamiento & purificación , Anciano , Anciano de 80 o más Años , Antibacterianos/uso terapéutico , Infección Hospitalaria/epidemiología , Infección Hospitalaria/mortalidad , Infección Hospitalaria/patología , Femenino , Humanos , Unidades de Cuidados Intensivos , Masculino , Factores de Riesgo , Choque Séptico/mortalidad , Choque Séptico/patologíaRESUMEN
Thermostable direct haemolysin (TDH) produced by Vibrio parahaemolyticus is thought to play an important role in the severe diarrhoea caused by this organism. This study investigated the enterotoxicity of TDH for human intestinal cells. Addition of TDH to the mucosal side of human colonic tissue in Ussing chambers caused increased short circuit currents (Isc), a process that was inhibited by 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS), an inhibitor of Ca2+ -activated chloride (Cl-) channels. With human colonic epithelial (Caco-2) cells, high Isc and intracellular Ca2+ concentrations ([Ca2+]in) were detected after the addition of TDH to the apical side of the cell monolayer. The Isc decreased with the addition of DIDS, but not with glybenclamide, 5-nitro-2-(3-phenylpropylamino) benzoic acid, or gadolinium chloride. No Isc increase with TDH was observed when the Cl- in the medium was replaced by gluconate or when Ca2+ was depleted. Similarly, TDH did not raise [Ca2+]in after depletion of extracellular Ca2+. R7, a mutant form of TDH, reduced the effects of TDH on Isc and [Ca2+]in, as did protein kinase C (PKC) inhibitors. Thus, TDH increases Cl- secretion in human colonic epithelial cells, apparently through mechanisms involving cell binding and Ca2+ influx, followed by elevation of [Ca2+]in associated with PKC phosphorylation.
Asunto(s)
Cloruros/metabolismo , Enterotoxinas/farmacología , Proteínas Hemolisinas/farmacología , Intestinos/efectos de los fármacos , Vibrio parahaemolyticus/patogenicidad , Ácido 4,4'-Diisotiocianostilbeno-2,2'-Disulfónico/farmacología , Toxinas Bacterianas , Transporte Biológico , Células CACO-2 , Calcio/metabolismo , Línea Celular , Canales de Cloruro/antagonistas & inhibidores , Colon/citología , Colon/efectos de los fármacos , Cámaras de Difusión de Cultivos , Conductividad Eléctrica , Enterotoxinas/genética , Proteínas Hemolisinas/genética , Humanos , Mucosa Intestinal/citología , Mucosa Intestinal/efectos de los fármacos , Intestinos/citología , Proteína Quinasa C/antagonistas & inhibidores , Proteínas Recombinantes/farmacologíaRESUMEN
Infection of cultured HeLa epithelial cells with enteropathogenic Escherichia coli (EPEC) or enterohemorrhagic E. coli (EHEC) O157:H7 results in accumulation of cortactin under the adherent bacteria. Tyrosine phosphorylation of cortactin is not induced following HeLa cell infection with EHEC or EPEC, contrary to what has been reported to occur with Shigella flexneri.
Asunto(s)
Adhesión Bacteriana/fisiología , Escherichia coli O157/patogenicidad , Escherichia coli/patogenicidad , Proteínas de Microfilamentos/fisiología , Actinas/metabolismo , Sitios de Unión , Cortactina , Citocalasina D/farmacología , Inhibidores Enzimáticos/farmacología , Escherichia coli/fisiología , Escherichia coli O157/fisiología , Células HeLa , Humanos , Microscopía Confocal , Fosforilación , Unión Proteica , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Shigella flexneri/patogenicidad , Shigella flexneri/fisiología , Estaurosporina/farmacología , Tirosina/metabolismo , VirulenciaRESUMEN
Enteropathogenic Escherichia coli (EPEC) is able to inject its own receptor, a transmembrane protein called translocated intimin receptor, Tir, into the host epithelial cell. The bacterium then uses an outer membrane protein, intimin, to bind to Tir and remains firmly attached to the host cell surface for the duration of the infection. The bacterium is also able to trigger the rearrangement of several host cell proteins, culminating with the formation of an actin-rich, pedestal-like structure beneath the EPEC adherence site. Although several cytoskeletal proteins are rearranged following EPEC infection, the exact role played by these proteins during pedestal formation remains unknown. We report here that talin, an integrin-binding protein, is recruited by EPEC and associates directly with Tir. By surface plasmon resonance (SPR), the predicted value for the dissociation constant (KD) for Tir-talin binding was 1.86 x 10(-7) M. We also demonstrate that microinjection of anti-talin antibodies into HeLa cells resulted in the complete inability to focus actin filaments beneath the attached bacterium. These findings demonstrate that talin is essential for EPEC-induced pedestal formation in infected cells.