Revista latinoamericana de microbiologia最新文献

Opioids like morphine, represent a major source of relief for most chronic moderate to severe nonmalignant pain. However, opioid abuse may lead to infections such as hepatitis and AIDS because opioids have been associated with suppressing various parameters of immune function including antimicrobial resistance, antibody production, monocyte-mediated phagocytosis, and both neutrophil and monocyte chemotaxis. We have previously reported immunopotentiating properties of non-peptidic opioid receptor selective agonists and antagonists. In this study, we evaluated the effects of the nonpeptidic delta-opioid receptor agonist (+)-4-((alpha R)-alpha-((2S, 5R)-4-allyl-2, 5-dimethyl-1-piperazinyl)-3-methoxybenzyl)-N, N-diethyl-benzamide (SNC 80) on chemotaxis of rat thymic and human peripheral blood mononuclear cells by using a modified Wilkinson chamber. Cell recruitment is an essential process in acute and chronic inflammatory responses. We observed that SNC 80 at concentrations of 10(-10), 10(-9), 10(-8), 10(-7), and 10(-6) M, significantly (p < 0.01) stimulated rat thymic (1.3, 1.55, 1.58, 1.75, and 1.8-fold increases respectively) and human leukocyte (1.13, 1.37, 1.43, 1.7, 1.83 fold-increases respectively) chemotaxis (demonstrated by checkerboard assays), compared with untreated control. The effects of SNC 80 on chemotaxis of rat and human leukocytes were antagonized by naloxone, indicating that the modulation of chemotaxis by SNC 80 is via a classic opioid receptor. The development and use of non-peptidic opioids like SNC 80 could have an immediate impact not only as potent analgesics, but in immunoregulation.

The importance of ecological concepts to understand the presence and growth of microorganisms in foods is presently recognized. The production of fermented foods under controlled conditions and its safety assurance depend on the knowledge and control of their microbiota. Traditional fermented foods are obtained by natural fermentations (in which no inoculum is added) and contain complex microbiotas, which are difficult to describe through the use of traditional microbiological methods. The microbial structure of these foods can be studied with different approaches. One of them consists on the typification of isolated microorganisms with methods based on DNA as RFLP, ribotyping, AFLP, ARDRA and RAPD. In order to detect non-culturable or not yet cultured microorganisms, nucleic acids are directly extracted from foods and the microbial diversity is determined from them. Examples of these techniques are the construction of 16S rDNA clone libraries and fingerprinting techniques, such as DGGE and TGGE. Recent advances on the application of these techniques on the study of fermented foods are presented.

Siderophores are compounds secreted under low iron stress, that act as a specific ferric iron chelate agents and due to their potentialities in the biological control of phytopathogenic fungi and bacteria, their study has been stimulated in recent years. Siderophores produced by different Pseudomonas species have been widely studied as biological agents and it is an alternative to take into account in the control of phytopathogenic microorganisms in agriculture. The purpose of this paper was to study the influence of some culture medium, and the iron concentration in the production of this metabolite. The experiments were carried out in a conventional batch system in succinate, glucose and glutamate medium. The highest metabolite concentration was obtained in glucose and glutamate medium. The increase of Fe(III) concentration, had a negative effect in siderophores production, especially above 10 microM. The evaluation of the studied media led to the conclusion that it is possible to increase the production of this metabolite by the strain of Pseudomonas aeruginosa PSS, in a glutamate medium without iron addition.

Paratuberculosis (Johne's disease) is a chronic enteritis that affects ruminants and is caused by Mycobacterium avium subsp. paratuberculosis (Map). The disease is worldwide spread and causes important economic losses. In Brazil, Map has already been isolated, but there are no enough epidemiological studies about its prevalence. In this study, 179 sera of dairy cows originated from Rio de Janeiro State, Brazil, were tested for the presence of anti-Map antibodies using two ELISAs. First one was an "in house" ELISA using a protoplasmic paratuberculosis antigen (PPA - Allied Monitor) as capture antigen and a monoclonal anti-bovine IgG conjugated to alkaline phosphatase (Sigma) and the other was "HerdChek Mpt" (IDEXX), used as standard method in this study. Fifty-nine (32.9%) samples were reactive in the PPA-ELISA. Sensitivity of ELISA-PPA in relation to HerdCheck was 47.5% and specificity was 86.8%, with 54/103 of false negatives and 10/76 of false positives. Positive predictive value of PPA-ELISA was calculated as 86% and efficiency as 64.2%. PPA-ELISA and HerdChek results were also compared by kappa test (k) and concordance index was 0.320. PPA-ELISA can be useful as a collective herd test and can be recommended as a screening test for identification of infected herds and foci of Johne's disease.

The term halophile is used for all those organisms belonging to hypersaline habitats; they constitute an interesting class of organisms able to compete successfully in salt water and to resist its denaturing effects. A wide diversity of microorganisms, prokaryotic and eukaryotic belong to this category. Halophile organisms have strategies allowing them not only to withstand osmotic stress, but also to function better in the presence of salt, in spite of maintaining high intracellular concentrations of salt, partly due to the synthesis of compatible solutes that allow them to balance their osmotic pressure. We describe the characteristics of some halophile organisms and D. hansenii (halophile yeast), that allow them to resist high concentrations of salt. The interest to know the great diversity microorganisms living in hypersaline habitats is growing, and has begun to be the center of recent investigations, since halophile organisms produce an wide variety of biomolecules that can be used for different applications. In this review we describe some mechanisms with which some halophile organisms count to resist the high concentration of salts, mainly NaCl.

The direct fluorescent antibody test (DFAT) for the diagnosis of Bovine Genital Campylobacteriosis was assessed for its detection limit, observer effect, sensitivity and specificity. In addition, the specificity of the fluorescent conjugate was tested against Campylobacter sp, Arcobacter sp, Helicobacter sp, E. coli and other bacteria from the preputial flora. Ten - fold dilutions of C. fetus subsp. venerealis NCTC 10354 in PBS or preputial washings with or without centrifugation were used. All experiments were done in duplicate by three observers. Positive and negative controls were included in each assay. The detection limits of DFAT were 10(4) CFU/ ml for PBS and non - centrifuged preputial washings and 10(2) CFU/ ml for centrifuged preputial washings. There was no observer effect. The sensitivity and specificity of DFAT were 92.59% and 88.89%, respectively. The DFAT was observed to be sensitive, specific and the effect of experienced observers was minimal on test performance.

The standard method for the diagnostic of leptospirosis is the microscopic agglutination test (MAT). Nevertheless, it is time-consuming and presents risk of infection for laboratory personal. Several attempts to simplify and reduce the time, skill and expense required for serological testing were made. Rapid slide agglutination tests (RSAT) have been used nowadays as a reliable screening test for the detection of acute and recent infections by many laboratories. The purpose of that study was to evaluate a new antigen preparation for the rapid diagnoses of acute canine leptospirosis and to compare it with MAT results in clinically suspect serum samples. Two hundred and thirteen serum samples from dogs of both sexes and different ages were tested and 141 (66.2%) animals were considered as positive by MAT. The most frequent serovar was icterohaemorrhagiae, followed by canicola. RSAT results were very similar to those observed on MAT, with 139 (65.3%) reactive animals. Correlation between RSAT and MAT was positive (0.82) and significant (p < 0.01). Concordance of results was of 93.4% (199/ 213) of the animals correctly diagnosed by RSAT. Considering MAT as the standard test, sensitivity of RSAT was calculated on 94.3% (133/141) and specificity on 91.7% (66/72).

Title: Serotypes and antimicrobial susceptibility of group B Streptococcus isolated from pregnant women in México

Background: Group B streptococci (SGB) are a leading cause of neonatal sepsis and meningitis. Women colonized might also develop pregnancy-associated infections including urinary tract infection, bacteremia and postpartum endometritis. There are nine different capsular types, and with the possibility of a GBS vaccine in the future; it is essential to understand which of these types are circulating. We determined the serotype distribution of isolated rectovaginal and urine GBS obtained from an obstetric population, and also their antibiotic sensitivity patterns.

Methods: A total of 101 strains were studied: SGB were confirmed by latex agglutination (Slidex Strepto-Kit bioMérieux), and the serotype was confirmed by latex agglutination (Pastorex Streptococcus B. Becton Dickinson, EUA). Antimicrobial susceptibility testing was performed by a Kirby-Bauer disk diffusion.

Results: All SGB were serologically typeable; 61.3% were type I, 25.7% were type II and only 12.8 were type III. All of them were 100% susceptible to beta lactam agents. Only 5.9% strains were resistant to erythromycin.

Conclusion: In the last years, no major changes have been observed in the distribution of serotypes of SGB in México, serotype I is still the most common. This makes us think of the possibility of a vaccine that includes serotypes I and II that represent close to 90% of the isolations.

Shigella boydii, Shigella flexneri, Shigella dysenteriae and Shigella sonnei were identified using gas chromatography instead of the traditional techniques. Their acid methyl esters profiles were determined using a gas chromatograph Hewlett Packard 5890A and a RSL-150 heliflex capillary column. A total of 192 samples were analyzed both reference strains (ATCC 8700, INDRE B2188, B2194 and B2199) and environmental isolates. 12 fatty acids were included in the profiles from which 3-hydroxytetradecanoic acid (peak 12), trans 9-octadecanoic acid (peak 22), heptadecanoic acid (peak 18) and octadecanoic acid (peak 23), were the most important for the differentiation of the species analyzed.

The proposed replacement of the gasoline oxygenate MTBE with ethanol represents potential economic and environmental quality benefits. However, these benefits may be offset to some extent by potential detrimental effects on groundwater quality and natural attenuation of released petroleum products. The objectives of this literature review are to bound the extent to which these impacts may occur, summarize the available information on the biodegradation of ethanol in the environment, assess the potential effect that biodegradation processes may have on the fate and transport of BTEX compounds, and provide recommendations for research to enhance related risk assessment and management decisions. Ethanol that reaches groundwater aquifers is likely to be degraded at much faster rates than other gasoline constituents. If the carbon source is not limiting, a preferential degradation of ethanol over BTEX may be observed under both aerobic and anaerobic conditions. Depending on the extent of the release, ethanol may exert a high biochemical oxygen demand that would contribute to the rapid depletion of dissolved oxygen in the groundwater. Thus, ethanol will likely be degraded predominantly under anaerobic conditions. None of the potential ethanol metabolites that could accumulate in groundwater are toxic, although some potential biodegradation by-products such as butyrate could adversely affect the taste and odor of drinking water sources. In addition, acetate and other volatile fatty acids could accumulate at high concentrations, causing a pH decrease in poorly buffered systems. It is unknown, however, whether the pH would decrease to a point that inhibits natural degradative processes. Inhibition of microbial, activity near the source is likely to occur as a result of exposure to high alcohol concentrations, and bactericidal effects are likely to occur when cells are exposed to ethanol concentrations exceeding 10,000 mg/L. However, the maximum allowable ethanol content in gasoline is 10% by volume in the United States. Thus, such high ethanol concentrations are unlikely to be encountered at sites contaminated with ethanol-gasoline blends, except near the fuel/water interfaces or in the case of neat ethanol releases. Downgradient of the source area, biodegradation is unlikely to be inhibited by alcohol toxicity as concentrations decrease exponentially with distance. The preferential degradation of fuel alcohols by indigenous microorganisms and the accompanying depletion of oxygen and other electron acceptors suggest that ethanol could hinder BTEX bioremediation. This is particularly important for the fate of benzene, which is the most toxic BTEX compound and the most recalcitrant under anaerobic conditions. Alternatively, ethanol represents a carbon and energy source that is likely to stimulate the growth of a variety of aerobic and anaerobic microbial populations, including those that can degrade BTEX compounds. A higher concentration of BTEX degra