RESUMEN
BACKGROUND: Carbapenem-resistant Acinetobacter baumannii infections are a major public health problem worldwide, requiring the use of "old" antibiotics such as polymyxin B and E (colistin). However, there is concern regarding the emergence of isolates resistant to these antibiotics. CASE PRESENTATION: We report a case of a 64-year-old mestizo man hospitalized in an intensive care unit of a health institution in Colombia with identification and clinical and molecular typing of a colistin- and carbapenem-resistant A. baumannii isolate with mechanisms of resistance to colistin not previously reported, causing bacteremia. CONCLUSIONS: We have identified a strain of A. baumannii with mechanisms of resistance to colistin not previously reported in a patient with bacteremia who required treatment with multiple antibiotic schemes and had an adequate response.
Asunto(s)
Infecciones por Acinetobacter/microbiología , Acinetobacter baumannii/efectos de los fármacos , Antibacterianos/farmacología , Infecciones Relacionadas con Catéteres/diagnóstico , Colistina/farmacología , Infecciones por Acinetobacter/diagnóstico , Infecciones por Acinetobacter/tratamiento farmacológico , Infecciones por Acinetobacter/etiología , Acinetobacter baumannii/aislamiento & purificación , Anciano , Bacteriemia/diagnóstico , Bacteriemia/tratamiento farmacológico , Bacteriemia/etiología , Bacteriemia/microbiología , Infecciones Relacionadas con Catéteres/tratamiento farmacológico , Infecciones Relacionadas con Catéteres/etiología , Infecciones Relacionadas con Catéteres/microbiología , Catéteres de Permanencia/efectos adversos , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Forty-three Bacillus thuringiensis isolates from Brazil and 3 from Argentina were screened, using the polymerase chain reaction (PCR), for various coleoptera-specific cry genes. Seven isolates produced specific and/or nonspecific DNA fragments in a PCR reaction with primers specific for two coleopteran cry genes and 4 of these produced DNA fragments with primers specific for 7 known coleopteran cry genes. These isolates showed, by electron microscopy, the presence of spherical crystals. They also showed proteins of around 70 kDa which were immunologically similar to the Cry3Aa protein from B. thuringiensis subsp. tenebrionis. The 3 isolates from Argentina were toxic to T. molitor, and although no isolate from Brazil showed toxicity, they might show toxicity to another insect species.
Asunto(s)
Bacillus thuringiensis/aislamiento & purificación , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Toxinas Bacterianas , Escarabajos/fisiología , Endotoxinas/genética , Endotoxinas/metabolismo , Control Biológico de Vectores , Animales , Bacillus thuringiensis/clasificación , Bacillus thuringiensis/genética , Bacillus thuringiensis/metabolismo , Toxinas de Bacillus thuringiensis , Proteínas Bacterianas/química , Brasil , Endotoxinas/química , Proteínas Hemolisinas , Microscopía Electrónica , Reacción en Cadena de la Polimerasa/métodosRESUMEN
We have studied the activity of a calcium dependent transglutaminase (EC 2.3.2.13) during the growth of the parasite Plasmodium falciparum inside the infected human erythrocyte. There is only one detectable transglutaminase in the two-cell-system, and its origin is erythrocytic. No activity was detected in preparations of the parasite devoid of erythrocyte cytoplasm. The Michaelis Menten constants (Km) of the enzyme for the substrates N'N' dimethylcaseine and putrescine were undistinguishable whether the cell extracts used in their determination were obtained from normal or from infected red cells. The total activity of transglutaminase in stringently synchronized cultures, measured at 0.5 mM Ca2+, decreased with the maturation of the parasite. However, a fraction which became irreversibly activated and independent of calcium concentration was detected. The proportion of this fraction grew with maturation; it represented only 20% of the activity in 20 hr-old-trophozoites while in 48-hr-schizonts it was more than 85% of the total activity. The activation of this fraction of transglutaminase did not depend on an increase in the erythrocyte cytoplasmic calcium, since most of the calcium was shown to be located in the parasite.