Investigación de Trichomonas vaginalis durante el embarazo mediante diferentes metodologías / Investigation of Trichomonas vaginalis through different methodologies during pregnancy

Los objetivos del trabajo fueron conocer la prevalencia de tricomonosis en pacientes embarazadas y evaluar la utilidad de diferentes metodologías para su diagnóstico. Se estudiaron prospectivamente 223 mujeres embarazadas. Trichomonas vaginalis se investigó utilizando distintos exámenes microscópicos, cultivo en medio sólido y medio líquido. Se evaluó la sensibilidad y especificidad de la microscopía considerando a los cultivos en ambos medios como método de referencia. La prevalencia del parásito obtenida por cultivo (medio líquido más medio sólido) fue de 4,5% (10/223) siendo la detección por examen en fresco, coloración de May-Grunwald Giemsa, fresco con solución acética formolada (SAF)/azul de metileno y por cultivo en medio sólido y líquido de 1,3%, 1,8%, 1,8% y 4,5% respectivamente. La sensibilidad del examen en fresco fue 30%, para el May-Grunwald Giemsa y el SAF/azul de metileno fue 40%. Utilizando conjuntamente los tres exámenes microscópicos, la sensibilidad se elevó al 50% y la especificidad fue 100% para todos los exámenes microscópicos. El cultivo en medio líquido detectó el 100% de los casos positivos , mientras que el medio sólido sólo el 50%. Por la baja sensibilidad de la microscopía para T. vaginalis, en embarazadas asintomáticas recomendamos la utilización del cultivo en medio líquido durante el embarazo, para instaurar un tratamiento precoz.

The aim of this study was to conduct a survey regarding the prevalence of trichomoniasis in pregnant patients and to evaluate the utility of different diagnostic methods. Two hundred and twenty three vaginal swab specimens from pregnant women were prospectively examined. Trichomonas vaginalis was investigated by various microscopic examinations, solid culture medium and liquid culture medium. The sensitivity and specificity of microscopy were evaluated by considering both culture media as the "gold standards". The prevalence of T. vaginalis obtained by both culture media (liquid plus solid media) was 4.5% (10/223). The prevalence of T. vaginalis obtained by direct smear, May-Grunwald Giemsa staining, sodium acetate-acetic acid-formalin (SAF)/Methylene blue staining-fixing technique, solid medium and liquid medium was 1.3%, 1.8%, 1.8% and 4.5%, respectively. The sensitivity of the direct smear was 30 %, but for the May- Grunwald Giemsa staining and the SAF/Methylene blue staining-fixing technique was 40%. Considering the three microscopic examinations altogether, the sensitivity rose to 50% and the specificity was 100% for all of them. The solid medium detected only 50% of the positive cases; the liquid medium detected 100%. Due to the low sensitivity obtained with microscopy in asymptomatic pregnant patients, we recommend the use of the liquid medium during pregnancy, in order to provide an early treatment.

Prevalencia de candidiasis vaginal en embarazadas: Identificación de levaduras y sensibilidad a los antifúngicos / Prevalence of vaginal candidiasis in pregnant women: Identification of yeasts and susceptibility to antifungal agents

La mujer embarazada es más susceptible tanto a la colonización como a la infección vaginal por levaduras. El objetivo de este trabajo fue determinar la prevalencia de levaduras aisladas de exudados vaginales de mujeres embarazadas y evaluar la sensibilidad a los antifúngicos de uso frecuente. Se estudiaron 493 pacientes en el período comprendido desde diciembre de 1998 hasta febrero de 2000. La prevalencia de Candida spp. fue 28% (Candida albicans 90,4%, Candida glabrata 6,3%, Candida parapsilosis 1,1%, Candida kefyr 1,1%, especies no identificadas 1,1%). Se determinó la sensibilidad a fluconazol, ketoconazol, itraconazol y nistatina por el método de difusión en agar Shadomy. Todos los aislamientos de C. albicans, C. kefyr y C. parapsilosis fueron sensibles in vitro a los antifúngicos probados, mientras que 1 de 6 aislamientos de C. glabrata presentó resistencia extendida a todos los azoles, pero sensibilidad a nistatina. En mujeres embarazadas C. albicans fue la levadura más frecuentemente aislada de exudados vaginales y continúa siendo ampliamente sensible a los antifúngicos; sólo en C. glabrata se observó resistencia a los azoles. Se recomienda la identificación de la levadura a nivel de especie particularmente en el caso de falla terapéutica y en infecciones recidivantes o crónicas.

Pregnant women are more susceptible to both vaginal colonization and infection by yeast. Our objectives were to determine the prevalence in pregnant women of yeasts isolated from vaginal exudates and their susceptibility to current antifungal drugs. A total of 493 patients was studied between December 1998 and February 2000. The prevalence of Candida spp. was 28% (Candida albicans 90.4%; Candida glabrata 6.3%; Candida parapsilosis 1.1%, Candida kefyr 1.1%; unidentified species 1.1%). The diffusion test in Shadomy agar was employed to determine the susceptibility to fluconazole, ketoconazole, itraconazole and nistatine. All C. albicans, C. kefyr and C. parapsilosis isolates were susceptible in vitro to the antifungal agents tested, while 1 in 6 C. glabrata isolates showed resistance to azole drugs; all strains were susceptible to nistatine. In pregnant women, C. albicans was the yeast most frequently isolated from vaginal exudates; it continues to be highly susceptible to antifungal drugs. Azole resistance was detected only among C. glabrata isolates. Identification to the species level is recommended, specially in cases of treatment failure and recurrent or chronic infection.

Detección de la actividad de desoxiribonucleasa (DNasa) en cepas de Clostridium chauvoei / [Deoxyribonuclease activity detection in Clostridium chauvoei strains]

Beta toxin of C. chauvoei has desoxiribonuclease (DNase) activity which is regarded as one of its virulence factors. The production of DNase was detected in strains isolated from bovines, using as controls C. chauvoei ATCC 10092, and C. perfringens Type A and C. septicum, both laboratory isolates. The enzyme activity was made evident on a DNA substrate observing the macroscopic degradation. A simple methodology was developed using a commercial medium for DNase test, with the incorporation of sterile horse serum. Each strain was streaked on the surface of the medium, incubated in anaerobic atmosphere at 37 degrees C for 48 hours. The plates were revealed with HCI 1 N. The appearance of a clear and transparent zone around and under the microbial growing was considered a positive reaction. Enzyme activity was detected in 10 of 12 strains and also in the controls. The serum addition to the commercial basal medium allows the optimum development of the microorganism showing the enzymatic digestion zone.

Portación de estreptococo grupo B en mujeres embarazadas / [Group B Streptococcus carriers among pregnant women]

Streptococcus agalactiae--group B streptococci (GBS)--is a main cause of severe neonatal infections with a high mortality rate. The detection of pregnant GBS carriers (5-35

) allows intrapartum administration of antibiotic prophylaxis to these women and prevents perinatal infection. We studied the prevalence of GBS in 259 patients between 28 and 37 weeks gestation from April 2000 to March 2002. The anorectum (AR) and vaginal introitus swabs (VI) were cultured in selective Todd-Hewitt broth containing colistin (10 micrograms/ml) and nalidixic acid (15 micrograms/ml) while vaginal swabs (VFS) were cultured following conventional methods. A total of 47 strains of EGB were isolated from 259 patients (18.15

). The prevalence in different samples were: 5.40

in AR and 17.76

in VI + AR (reference method). The isolates were tested against penicillin, ceftriaxone, erythromycin, clindamycin, vancomycin, gentamicin and streptomycin to determine the minimum inhibitory concentration. The resistance phenotypes of erythromycin-resistant GBS were determined by the double-disk test. All strains were susceptible to penicillin, ceftriaxone and vancomycin, only one strain was erythromycin and clindamycin resistant by IMLSB mechanism. None of the isolated strains had a high resistant level to aminoglycosides. The sensitivity of cultures increased when selective broths were used as the primary detection method.

Ensayos de citotoxicidad y actividad antiviral de extractos crudos y semipurificados de hojas verdes de Melia azedarach L / [Assays of cytotoxicity and antiviral activity of crude and semipurified extracts of green leaves of Melia azedarach L.]

Crude extracts from fresh green leaves of Melia azedarach L contain an antiviral factor (FAV) able to inhibit the replication of several animal viruses, e.g. Polio, VSV, HSV, FMDV, Sindbis, Junín, Pichinde and Tacaribe in Vero or BHK-21 cells. Crude preparations were subjected to different steps of purification like chromatography on Sephadex G-100 and DEAE-Sephadex. The antiviral activity of G-100 and DEAE fractions was fully conserved, whereas contaminating proteins were lost. Two types of cytotoxicity tests were performed with the different fractions. Two-fold serial dilutions of each of them were added to preformed monolayers of Vero or BHK-21 cells and cellular viability was tested. While crude extracts were toxic at low dilutions (less than or equal to 1:10), G-100 and DEAE fractions were not. The other cytotoxicity assay consisted in seeding the cells in the presence of different concentrations of each fraction. G-100 fraction affected cell growth at low dilutions (less than or equal to 1:5), while DEAE fraction did not. It should be remarked that the purification procedure rendered a partial purified DEAE fraction with an increased specific activity (antiviral activity/mg of protein). It is concluded that an antiviral factor devoid of toxicity exists in M. azedarach L extracts, which exhibited a broad spectrum of antiviral activity.