Synergistic effect between two bacteriocin-like inhibitory substances produced by Lactobacilli Strains with inhibitory activity for Streptococcus agalactiae.

Group B streptococci (GBS) are bacterial species that colonize the vagina in pregnant women and as such may cause serious infections in neonates that passed through the birth channel. The objective of this work was to study the inhibitory activities produced by each bacteriocin-like inhibitory substance (BLIS) of Lactobacillus rhamnosus L60 and Lactobacillus fermentum L23, and the effects of the combined BLIS-es of these lactobacilli on GBS. The interactions between the BLIS-es were assessed by qualitative and quantitative methods on agar plates. The minimum inhibitory concentrations (MICs) and fractional inhibitory concentrations (FICs) were determined by a modification of the broth microdilution and checkerboard methods, respectively. Antibiotic susceptibilities of all S. agalactiae strains were assayed and the results of these tests were evaluated for statistical significance. A 7.5% of GBS isolates were recovered from 760 pregnant women and 91% of those strains were susceptible to each BLIS produced by L. fermentum, L. rhamnosus, and also to a mixture of them. The comparisons among the BLIS-es showed statistically significant differences, with a combination of the BLIS-es from the two Lactobacillus species being better than the BLIS of each one alone (P < 0.05) as GBS growth inhibitors. Synergistic activities between the BLIS-es were found on 100% of susceptible GBS strains, MICs ranges of BLIS of L23 and L60 were 80-160 and 160-320 UA ml(-1), respectively. By the checkerboard method, the BLIS-es combination showed synergistic effect on all sensitive strains tested, with values of FICs ranging from 0.131 to 0.218. The BLIS-es produced by these lactobacilli of vaginal origin were able to inhibit S. agalactiae isolates. The results indicate that these strains may have probiotic potential for the control of GBS in women and may consequently prevent GBS infections in newborns.

Surveillance of Aflatoxin and Microbiota Related to Brewer's Grain Destined for Swine Feed in Argentina.

Córdoba province in the center of Argentina is an important area of swine production. The use of industry by-product (brewer's grain) as feedstuff for swine is a regular practice and increases animal performance on these animals production. The occurrence of aflatoxin contamination is global, causing severe problems especially in developing countries. No reports on aflatoxin B(1) production, micoflora, and potential aflatoxin B(1) producing microorganism from brewer's grain are available. The aims of this study were (1) to isolate the microbiota species from brewer's grain, (2) to determine aflatoxin B(1) natural contamination levels, and (3) to determine the ability of Aspergillus section Flavi isolates to produce aflatoxins in vitro. Physical properties, total fungal counts, lactic acid bacteria, and fungal genera distribution were determined on this substrate. In 65% of the samples, fungal counts were higher than recommended by GMP, and lactic bacterium counts ranged from 1.9 × 10(5) to 4.4 × 10(9) CFU g(-1). Aspergillus spp. prevailed over other fungal genera. Aspergillus flavus was the prevalent species followed by A. fumigatus. Aflatoxin B(1) levels in the samples were higher than the recommended limits (20 ng g(-1)) for complementary feedstuffs. Several Aspergillus section Flavi strains were able to produce aflatoxin B(1) in vitro. Inadequate storage conditions promote the proliferation of mycotoxin-producing fungal species. Regular monitoring of feeds is required in order to prevent chronic and acute toxic syndromes related to this kind of contamination.

Antimicrobial activity, inhibition of urogenital pathogens, and synergistic interactions between lactobacillus strains.

Lactobacillus fermentum strain L23 and L. rhamnosus strain L60 were selected as an alternative treatment to prevent or treat urogenital infections based on their probiotic properties and production of bacteriocins. The objectives of the present work were to study the inhibitory activities of these two bacteriocin-producing strains, and to analyze the interactions between pairs of bacteriocins that inhibit urogenital pathogens. Antimicrobial activity tests of L23 and L60 were performed by a diffusion method with 207 bacterial strains, isolated from female patients presenting a urogenital infection. Inhibitory substances interaction tests were carried out by using a streak-diffusion method on agar plates. One hundred percent of the clinical isolates showed sensitivity to the antimicrobial substances produced by L23 and L60. The selected lactobacilli produced larger inhibition halos when compared to several antibiotics commonly used for treating these infections. Synergistic interactions and indifferent interactions were recorded in 68.6% and 31.4% of the cases, respectively. No antagonistic interactions were observed. In conclusion, the bacteriocin-producing strains L23 and L60 are potential candidates for probiotic prophylaxis and treatment of urogenital disorders in women.

Purification and partial characterization of novel bacteriocin L23 produced by Lactobacillus fermentum L23.

Lactobacillus fermentum strain L23 produced a small bacteriocin, designated bacteriocin L23, with an estimated molecular mass of < 7000 Da. Isolation, purification, and partial characterization of bacteriocin L23 are described. It displayed a wide inhibitory spectrum including both Gram-negative and Gram-positive pathogenic strains and two species of Candida. The antibacterial activity of cell-free culture supernatant fluid was not affected by catalase or urease but was abolished by the proteolytic enzymes trypsin and protease VI. Bacteriocin L23 was heat stable (60 min at 100 degrees C) and showed inhibitory activity over a wide pH range (4.0 to 7.0). The proteinaceous compound was isolated from cell-free culture supernatant fluid and purified. Crude bacteriocin sample was prepared by a process of ammonium sulfate precipitation, gel filtration, thin-layer chromatography, bioautography, and reversed-phase HPLC.

Relevamiento de las enfermedades de transmision sexual en la region de Rio Cuarto / Survey of sexually transmitted diseases in the region of Rio Cuarto

Las enfermedades de transmisión sexual (ETS) conforman el grupo más frecuente de enfermedades infecciosas de declaración obligatoria. La identificación de nuevos patógenos y una distribución más amplia, ha hecho que sean consideradas uno de los problemas de salud pública más importantes. El objetivo de este trabajo fue conocer el estado actual de las ETS y comparar métodos diagnósticos para diferentes infecciones en la población estudiada. Se procesaron muestras de flujos vaginales, materiales endocervicales y exudados uretrales de 1060 pacientes, durante 3 años, de las que 583 fueron positivas para uno o más microorganismos, correspondiendo a 493 mujeres y 90 hombres. Los microorganismos hallados en mujeres fueron: Gardnerella vaginalis (39.3 por ciento), Candida albicans (21.1 por ciento), Trichomonas vaginalis (17.3 per ciento), Chlamydia trachomatis (11.3 por ciento); Neisseria gonorrhoeae (3.2 por ciento); Mycoplasma hominis; Ureaplasma urealyticum (6.5 por ciento) y Treponema pallidum (1.4 por ciento). Las asociaciones fueron, Gardnerella vaginalis con Trichomona vaginalis (5.5 por ciento); Gardnerella vaginalis con Candida albicans (4.9 por ciento); Trichomonas vaginalis con Neisseira gonorrhoeae (2.2 por ciento) y Gardnerella vaginalis con Chlamydia trachomatis (1.9 por ciento). En hombres la uretritis gonocócicas (UG) representó en 37.7 por ciento, las uretritis no gonocócica (UNG) 55.6 por ciento y Treponema pallidum 6.7 por ciento. Se observó disminución de sífilis, UG y cervicitis gonocócica, aumentando la prevalencia de las uretritis y cervicitis no gonocócicas. De este trabajo se desprende la necesidad de dar mayor énfasis en la búsqueda de Chlamydia trachomatis, por el riesgo de transmisión vertical en el embarazo. A pesar de ciertas fluctuaciones la incidencia de las ETS en nuestro medio, sigue siendo elevada.

Relevamiento de las enfermedades de transmision sexual en la region de Rio Cuarto / Survey of sexually transmitted diseases in the region of Rio Cuarto

Las enfermedades de transmisión sexual (ETS) conforman el grupo más frecuente de enfermedades infecciosas de declaración obligatoria. La identificación de nuevos patógenos y una distribución más amplia, ha hecho que sean consideradas uno de los problemas de salud pública más importantes. El objetivo de este trabajo fue conocer el estado actual de las ETS y comparar métodos diagnósticos para diferentes infecciones en la población estudiada. Se procesaron muestras de flujos vaginales, materiales endocervicales y exudados uretrales de 1060 pacientes, durante 3 años, de las que 583 fueron positivas para uno o más microorganismos, correspondiendo a 493 mujeres y 90 hombres. Los microorganismos hallados en mujeres fueron: Gardnerella vaginalis (39.3 por ciento), Candida albicans (21.1 por ciento), Trichomonas vaginalis (17.3 per ciento), Chlamydia trachomatis (11.3 por ciento); Neisseria gonorrhoeae (3.2 por ciento); Mycoplasma hominis; Ureaplasma urealyticum (6.5 por ciento) y Treponema pallidum (1.4 por ciento). Las asociaciones fueron, Gardnerella vaginalis con Trichomona vaginalis (5.5 por ciento); Gardnerella vaginalis con Candida albicans (4.9 por ciento); Trichomonas vaginalis con Neisseira gonorrhoeae (2.2 por ciento) y Gardnerella vaginalis con Chlamydia trachomatis (1.9 por ciento). En hombres la uretritis gonocócicas (UG) representó en 37.7 por ciento, las uretritis no gonocócica (UNG) 55.6 por ciento y Treponema pallidum 6.7 por ciento. Se observó disminución de sífilis, UG y cervicitis gonocócica, aumentando la prevalencia de las uretritis y cervicitis no gonocócicas. De este trabajo se desprende la necesidad de dar mayor énfasis en la búsqueda de Chlamydia trachomatis, por el riesgo de transmisión vertical en el embarazo. A pesar de ciertas fluctuaciones la incidencia de las ETS en nuestro medio, sigue siendo elevada. (AU)