Properties of Beta-lactamase from Neisseria gonorrhoeae

Beta-lactamase activity was studied in Neisseria gonorrhoeae strains. Optimum temperature was found to be 37 C. The enzyme was inactivated at temperatures higher than 60 C, but remained active during storage at low temperatures (4 C, -30 C and -70 C) for two months. Enzyme activity was observed within a pH range of 5.8-8.0, while the optimum pH was 7.0-7.2. Addition of Ni^2+, Fe^2+, Fe^3+, Mn^2+ and p-chloromercurybenzoate to the reaction buffer exerted a negative effect upon the activity, whereas Hg^2+ and ethylene diamine tetra-acetic acid produced complete inhibition. These results would indicate the presence of -SH groups at the catalytic site of the enzyme

In vitro Comparison of Disk Diffusion and Agar Dilution Antibiotic Susceptibility Test Methods for Neisseria gonorrhoeae

At present, most Neisseria gonorrhoeae testing is done with beta-lactamase and agar dilution tests with common therapeutic agents. Generally, in bacteriological diagnosis laboratories in Argentina, study of antibiotic susceptibility of N.gonorrhoeae is based on beta-lactamase determination and agar dilution method with common therapeutic agents. The National Committee for Clinical Laboratory Standards (NCCLS) has recently described a disk diffusion test that produces results comparable to the reference agar dilution method for antibiotic susceptibility of N.gonorrhoeae, using a dispersion diagram for analyzing the correlation between both techniques. We obtained 57 gonococcal isolates from patients attending a clinic for sexually transmitted diseases in Tucuman, Argentina. Antibiotic susceptibility tests using agar dilution and disk diffusion techniques were compared. The established NCCLS interpretive criteria for both susceptibility methods appeared to be applicable to domestic gonococcal strains. The correlation between the MIC's and the zones of inhibition was studied for penicillin, ampicillin, cefoxitin, spectinomycin, cefotaxime, cephaloridine, cephalexin, tetracycline, norfloxacin and kanamycin. Dispersion diagrams showed a high correlation between both methods. {P

Microbial flora variations in the respiratory tract of mice

A stable microbial system in the respiratory tract acts as an important defense mechanism against pathogenic microorganisms. Perturbations in this system may allow pathogens to establish. In an ecological environment such as the respiratory tract, there are many diverse factors that play a role in the establishment of the indigenous flora. In the present work we studied the normal microbial flora of different areas of the respiratory tract of mice and their evolution from the time the mice were born. Our interest was to know which were the dominant groups of microorganisms in each area, which were the first capable of colonizing and which dominated over time to be used as probiotic microorganisms. Our results show that Gram negative facultatively anaerobic bacilli and strict anaerobic microorganisms were the last ones to appear in the bronchia, while aerobic and Gram positive cocci were present in all the areas of the respiratory tract. The number of facultative aerobes and strict anaerobes were similar in the nasal passage, pharynx instilled and trachea, but lower in bronchia. The dominant species were Streptococcus viridans and Staphylococcus saprophyticcus, followed by S. epidermidis, Lactobacilli and S. cohnii I which were present on every studied days but at different proportions. This paper is the first part of a research topic investigating the protective effect of the indigenous flora against pathogens using the mice as an experimental model

Microbial flora variations in the respiratory tract of mice

A stable microbial system in the respiratory tract acts as an important defense mechanism against pathogenic microorganisms. Perturbations in this system may allow pathogens to establish. In an ecological environment such as the respiratory tract, there are many diverse factors that play a role in the establishment of the indigenous flora. In the present work we studied the normal microbial flora of different areas of the respiratory tract of mice and their evolution from the time the mice were born. Our interest was to know which were the dominant groups of microorganisms in each area, which were the first capable of colonizing and which dominated over time to be used as probiotic microorganisms. Our results show that Gram negative facultatively anaerobic bacilli and strict anaerobic microorganisms were the last ones to appear in the bronchia, while aerobic and Gram positive cocci were present in all the areas of the respiratory tract. The number of facultative aerobes and strict anaerobes were similar in the nasal passage, pharynx instilled and trachea, but lower in bronchia. The dominant species were Streptococcus viridans and Staphylococcus saprophyticcus, followed by S. epidermidis, Lactobacilli and S. cohnii I which were present on every studied days but at different proportions. This paper is the first part of a research topic investigating the protective effect of the indigenous flora against pathogens using the mice as an experimental model

Conjugated linoleic acid in Bufalo (Bubalus bubalis) milk from Argentine

Conjugated linoleic acid (CLA), a naturally occurring anticarcinogen found in dairy products, has received increasing attention in recent years. Twelve lactating Murrah river buffaloes (Bubalus bubalis) were used to study profile long-chain fatty acids in milk fat. Buffaloes were fed with natural pasture ad libitum. Milk samples were collected in the morning. Animals were separated by stage lactation (3-4 months). The composition of milk samples and fatty acids profile was analyzed. Milk was refrigerated, homogenized and pasteurized for evaluating any possible effect of treatment on cis9, trans11 octadecadienoic acid (CLA) level. Results show that 59% of long chain fatty acids are saturated. C16:0 was the most abundant fatty acid in buffalo milk and C18:1 the major unsaturated fatty acid. CLA level in buffalo milk was 4.83 mg/g of fatty acid methyl ester (FAME). There was a positive correlation between CLA and trans-11 C18:1 vaccenic acid. Any treatment of buffalo raw milk modified significantly CLA content or other fatty acids. Milk fat content of trans11 C18:1 and CLA were closely related (r = 0.90). A high quality of buffalo milk was obtained after a diet based only on cultured of pasture carried out in Northwest Argentine.Fil: Van Nieuwenhove, Carina Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; ArgentinaFil: Gonzalez, Silvia Nelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Perez Chaia, Adriana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Pesce de Ruiz Holgado, Aida Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentin

Vaginal bacterial microflora modifications during the growth of healthy cows

The aim of this work was first, to determine the predominant groups capable of colonizing the vagina and maintaining high numbers with time. The normal microbial flora of the cow's vagina and its evolution from weaning to service was then studied using standard microbiological methods. The results show that the most dominant bacteria belong to the streptococci, followed by the staphylococci, with similar levels during the whole study period. Enterobacteriaceae and lactobacilli were present at very low levels, the latter increasing during the cow's growth, suggesting some kind of hormonal influence. The results will allow the selection of micro-organisms with probiotic characteristics, classified as GRAS (Generally Regarded as Safe), to be used in the prevention of infections in the vaginal tract of cows, such as metritis, which produces delayed periods between partum and conception, and consequent economic losses.Fil: Otero, María Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Saavedra, Maria Lucila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Silva De Ruiz, C.. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Wilde, O.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Pesce de Ruiz Holgado, Aida Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Nader, Maria Elena Fatima. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentin

Estimation of vaginal probiotic lactobacilli growth parameters with the application of the Gompertz model

Lactobacilli are widely described as probiotic microorganisms used to restore the ecological balance of different animal or human tracts. For their use as probiotics, bacteria must show certain characteristics or properties related to the ability of adherence to mucosae or epithelia or show inhibition against pathogenic microorganisms. It is of primary interest to obtain the highest biomass and viability of the selected microorganisms. In this report, the growth of seven vaginal lactobacilli strains in four different growth media and at several inoculum percentages was compared, and the values of growth parameters (lag phase time, maximum growth rate, maximum optical density) were obtained by applying the Gompertz model to the experimental data. The application and estimation of this model is discussed, and the evaluation of the growth parameters is analyzed to compare the growth conditions of lactobacilli. Thus, these results in lab experiments provide a basis for testing different culture conditions to determine the best conditions in which to grow the probiotic lactobacilli for technological applications.Les lactobacilles sont généralement décrits comme étant des micro-organismes probiotiques utilisés pour rétablir l’équilibre écologique de diverses canalisations animales ou humaines. Pour être considérées comme probiotiques, les bactéries doivent présenter certaines caractéristiques ou propriétés liées à la capacité à adhérer aux muqueuses ou aux épithéliums, ou à inhiber certains micro-organismes pathogènes. Il est donc du plus grand intérêt d’obtenir un importante biomasse et un viabilité élevée des micro-organismes sélectionnés. Dans cet rapport, nous avons comparé la croissance de sept souches de lactobacilles vaginaux dans quatre différents milieux de culture et à divers pourcentages d’inoculation, et les valeurs des paramètres de croissance (temps de phase de latence, taux de croissance maximum, densité optique maximale) ont été obtenus en appliquant aux données expérimentales le modèle de Gompertz. L’application et l’évaluation de ce modèle est discuté, et les paramètres de croissance sont estimés et analysés afin de comparer les conditions de croissance des lactobacilles. Ainsi, les résultats des expériences en laboratoire fournissent une base pour l’analyse de différentes conditions de culture dans le but de déterminer les meilleures conditions sous lesquelles devraient être cultivées les lactobacilles probiotiques pour des procédés technologiques.Fil: Juárez Tomás, María Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Bru Chauve, Elena Magdalena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Pesce de Ruiz Holgado, Aida Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Nader, Maria Elena Fatima. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentin

Identification and nucleotide sequence of genes involved in the synthesis of lactocin 705, a two-peptide bacteriocin from Lactobacillus casei CRL 705

The structural gene determinants of lactocin 705, a bacteriocin produced by Lactobacillus casei CRL 705, have been amplified from a plasmid of approximately 35 kb and sequenced. Lactocin 705 is a class IIb bacteriocin, whose activity depends upon the complementation of two peptides (705α and 705β) of 33 amino acid residues each. These peptides are synthesized as precursors with signal sequences of the double-glycine type, which exhibited high identities with the leader peptides of plantaricin S and J from Lactobacillus plantarum, brochocin C from Brochotrix campestris, sakacin P from Lactobacillus sake, and the competence stimulating peptides from Streptococcus gordonii and Streptococcus mitis. However, the two mature bacteriocins 705α and 705β do not show significant similarity to other sequences in the databases.Fil: Cuozzo, Sergio Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Sesma, Fernando Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Palacios, Jorge Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Pesce de Ruiz Holgado, Aida Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Raya, Raul Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentin

Effect of Lactobacillus reuteri on the prevention of hypercholesterolemia in mice

Administration of Lactobacillus reuteri CRL 1098 (104 cells/d) to mice for 7 d before inducing hypercholesterolemia (by feeding mice with a fat-enriched diet for the subsequent 7 d) was evaluated. At this low dose, L. reuteri was effective in preventing hypercholesterolemia in mice, producing a 17% increase in the ratio of high-density lipoprotein to low-density lipoprotein. Total cholesterol and triglycerides decreased by 22 and 33%, respectively, in the group that was not fed the lactobacilli. The hypocholesterolemic effect produced by L. reuteri CRL 1098 might be considered as indirect evidence of the permanency of the lactobacilli in the gut.Fil: Taranto, Maria Pia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Medici, Marta Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Perdigon, Gabriela del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Pesce de Ruiz Holgado, Aida Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Font, Graciela Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentin