RESUMEN
AIM OF THIS STUDY: The aim of this study was to compare the mycobacteria growth indicator tube and solid culture for recovery of complex tuberculosis mycobacteria from blood. PATIENTS AND METHODS: One hundred and twenty-five specimens from 67 Djiboutian patients with a positive serologic diagnosis of HIV and fever were collected in an Isolator tube. After centrifugation and washing with phosphate-buffer, smears were prepared from the pellet for auramin staining. The remaining sediment was suspended in 1 ml of buffer. One half was inoculated into two MGIT (incubation at 30 and 37 degrees C into Bactec 960) and the other onto two Loewenstein-Jensen and two Coletsos medium (incubation at 30 and 37 degrees C). RESULTS: Eight cultures were contaminated: three on solid medium and MGIT simultaneously, five in MGIT only (three coagulase negative staphylococci, five enterobacteria). Fourteen strains of M. tuberculosis (six patients) and three M. canettii (two patients) (12 on solid media and MGIT, five in MGIT only) were recovered. The mean time to detection was 32.8 days for solid medium and 20.4 days for MGIT. Of a total of 25 patients with culture-proven tuberculosis, two patients had a positive blood culture only, six had blood and other specimens positive culture, 17 had a non blood specimens positive culture only. CONCLUSION: MGIT processed into Bactec 960 is a viable tool for the detection of complexe tuberculosis mycobacteria from blood and the high-frequency of these mycobacteremia in HIV infected patients from country where the prevalence of tuberculosis is high is confirmed. However, the cost/benefit ratio of this bacteriologic diagnosis had to be evaluated in developping country.
Asunto(s)
Bacteriemia/microbiología , Técnicas Bacteriológicas/métodos , Mycobacterium tuberculosis/aislamiento & purificación , Tuberculosis/microbiología , Adulto , Bacteriemia/complicaciones , Técnicas Bacteriológicas/instrumentación , Sangre/microbiología , Líquido Cefalorraquídeo/microbiología , Medios de Cultivo , Djibouti/epidemiología , Femenino , Fiebre/etiología , Contenido Digestivo/microbiología , Infecciones por VIH/sangre , Infecciones por VIH/complicaciones , Infecciones por VIH/epidemiología , Humanos , Masculino , Mycobacterium/crecimiento & desarrollo , Mycobacterium/aislamiento & purificación , Infecciones por Mycobacterium/sangre , Infecciones por Mycobacterium/complicaciones , Infecciones por Mycobacterium/epidemiología , Infecciones por Mycobacterium/microbiología , Mycobacterium tuberculosis/crecimiento & desarrollo , Prevalencia , Estudios Prospectivos , Sensibilidad y Especificidad , Tuberculosis/sangre , Tuberculosis/complicaciones , Tuberculosis/epidemiologíaRESUMEN
Serotyping is one of the most used techniques for typing Pseudomonas aeruginosa strains. During chronic infections, and especially in cystic fibrosis, the decrease of lipopolysaccharide production is responsible for difficulties in determining O antigens. The possibility of serotyping can be simply restored by using a primary culture broth containing amikacin (1/6 of the strain MIC for this antibiotic); this is due to the ability of this antibiotic to inhibit alginate production. This technique allowed us to determine the serotype of 108 non-serotypable strains of P. aeruginosa isolated in 14 different hospitals. Among these isolates, serotype O:1 and O:13, had a high prevalence; the origin is a deficiency in D-glucose and L-rhamnose, required for the synthesis of lipopolysaccharide. In contrast, these sugars are not present in lipopolysaccharide of O:12, and these strains are always serotypable. The main protein is Alg C; this bifunctional enzyme is required in the exopolysaccharide and lipopolysaccharide production, according stress conditions in the bacterial-cells' environment. Determination of the serotype, as Antibiogram, is essential for genotypic inquiries.
Asunto(s)
Técnicas de Tipificación Bacteriana/métodos , Pseudomonas aeruginosa/clasificación , Humanos , Infecciones por Pseudomonas/diagnóstico , Pseudomonas aeruginosa/aislamiento & purificaciónRESUMEN
In France all but one of the serological tests used to screen blood donations rely on ELISA-based techniques. The exception is malaria antibody detection that is performed by the indirect fluorescent antibody technique using commercially available kits. The reagent kit used at the French Army Blood Bank (FABB) is Falciparum-Spot IF (bioMerieux). However since the antigens in this kit are obtained from group A1 red blood cell cultures, false positive results can occur due to binding of natural antiglobulins. Over a 10-month period at the FABB, we disqualified a total of 55 donations (5.02% of total donations) because of positive Falciparum-Spot IF@1000 test results. Most disqualified donations (84%) involved donations with group O red blood cells. In the present retrospective study, these 55 disqualified donations were used to compare the specificity of three other serological tests used for detection of malaria antibodies: Falciparum-SpotIF after elimination of natural antiglobulins by absorption and neutralization with Witebski reagent and Paludix (Diagast). Use of all three techniques provided a specificity gain of over 87% but elimination using Witebski reagent led to a loss of sensitivity. At the FABB we have been using the Falciparum-Spot IF kit after elimination of natural antiglobulins since April 2001. Only 1.62% of donations tested have been disqualified due to the presence of malaria antibodies including 52% with group O red blood cells.
Asunto(s)
Anticuerpos Antiprotozoarios/análisis , Donantes de Sangre , Malaria Falciparum/diagnóstico , Malaria Falciparum/transmisión , Transfusión Sanguínea , Ensayo de Inmunoadsorción Enzimática , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , Malaria Falciparum/prevención & control , Sensibilidad y Especificidad , Pruebas SerológicasRESUMEN
Scytalidium dimidiatum is a fungus found mainly in tropical and subtropical zones. Infection can cause a benign disease closely resembling dermatophytosis. In immunocompromised hosts, Scytalidium dimidiatum can also lead to phaehyphomycosis. Although awareness of these hyphae remains limited in developed countries, their incidence is growing due to increasing immigration and tourism. The rising incidence is well illustrated by three patients who presented onyxis and squamous-like manifestations on the arch of the foot upon returning from trips overseas and in whom various treatments were unsuccessful. In all three cases, culture in non-selective Sabouraud medium identified Scytalidium dimidiatum. These findings underline the need for laboratory testing before undertaking local or systemic treatment of onyxis especially since this pathogen can cause systemic disease. Study of ribosome genes showed that Scytalidium hyalinum is an homologous unpigmented mutant form of Scytalidium dimidatum. No antifungal agent has been effective for management of superficial manifestations and prevention depends mainly on the use of appropriate footwear in endemic areas.