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1.
Arq. Inst. Biol ; 87: e0142020, 2020. tab
Article in English | LILACS, VETINDEX | ID: biblio-1130108

ABSTRACT

The genus Streptomyces is associated with the ability to produce and excrete a variety of bioactive compounds, such as antibiotic, antifungal and antiviral. Biological active polyketide and peptide compounds with applications in medicine, agriculture and biochemical research are synthesized by PKS-I and NRPS genes. The evaluation of the presence of these genes associated with the biosynthesis of secondary metabolites in different phytopathogenic Streptomyces strains were performed using degenerated primers. The positive signal was observed in 58/63 Streptomyces strains for NRPS gene, 43/63 for PKS-I, and for PKS-II all the 63 strains showed positive signal of amplification. These strains also were tested with double layer agar-well technique against bacterial with clinical importance, and it was possible to observe the Streptomyces spp. strains were able to inhibit the growth of 14, 20, 13 and 3 isolates Gram-positive and Gram-negative bacteria, Staphylococcus aureus (ATCC 25923), Bacillus cereus (ATCC 14579), Pseudomonas aeruginosa (ATCC 27853) and Escherichia coli (ATCC 11775) respectively. The Streptomyces sp. strains IBSBF 2019 and IBSBF 2397 showed antibacterial activity against all four bacteria-target tested.(AU)


O gênero Streptomyces apresenta alta capacidade de produzir e excretar uma grande variedade de compostos biologicamente ativos, como antibióticos, antifúngicos e antivirais. Compostos biologicamente ativos de policetídeos e peptídeos com aplicações na medicina, agricultura e pesquisas bioquímicas são sintetizados pelos genes PKS-I e NRPS. A avaliação da presença desses genes associados à biossíntese de metabólitos secundários em diferentes linhagens de Streptomyces fitopatogênicas foi realizada através do uso de primers degenerados. O sinal positivo foi observado em 58/63 linhagens de Streptomyces para o gene NRPS, 43/63 para o gene PKS-I e, para o gene PKS-II, todas as 63 linhagens apesentaram o sinal positivo de amplificação. Essas linhagens também foram testadas através da técnica de dupla camada contra bactérias de importância clínica e foi possível observar que as linhagens de Streptomyces spp. foram capazes de inibir o crescimento de 14, 20, 13 e 3 isolados de bactérias Gram-positivas e Gram-negativas, Staphylococcus aureus (ATCC 25923), Bacillus cereus (ATCC 14579), Pseudomonas aeruginosa (ATCC 27853) e Escherichia coli (ATCC 11775), respectivamente. As linhagens de Streptomyces sp. ISBSF 2019 e 2397 apresentaram atividade antibacteriana contra todas as bactérias-alvo testadas.(AU)


Subject(s)
Pseudomonas aeruginosa/growth & development , Staphylococcus aureus/growth & development , Streptomyces/metabolism , Bacillus cereus/growth & development , Escherichia coli/growth & development , Anti-Bacterial Agents/metabolism , Peptide Synthases/genetics , Streptomyces/genetics , Gene Amplification , Polymerase Chain Reaction , Sequence Analysis, DNA , DNA Primers , Polyketide Synthases/genetics , Anti-Bacterial Agents/pharmacology
2.
Rev. Soc. Bras. Med. Trop ; 52: e20180152, 2019. tab, graf
Article in English | LILACS | ID: biblio-1041546

ABSTRACT

Abstract INTRODUCTION: Introducing new antibiotics to the clinic is critical. METHODS: We adapted a plate method described by Kawaguchi and coworkers in 20131 for detecting inhibitory airborne microorganisms. RESULTS: We obtained 51 microbial colonies antagonist to Chromobacterium violaceum, purified and retested them, and of these, 39 (76.5%) were confirmed. They comprised 24 bacteria, 13 fungi, and 2 yeasts. Among the fungi, eight (61.5%) produced active extracts. Among the bacterial, yeast, and fungal strains, 17 (44.7%) and 12 (31.6%) were active against Candida albicans and Candida parapsilosis, respectively. CONCLUSIONS: The proposed screening method is a rapid strategy for discovering potential antibiotic producers.


Subject(s)
Bacteria/isolation & purification , Candida/drug effects , Chromobacterium/drug effects , Air Microbiology , Quorum Sensing , Fungi/isolation & purification , Anti-Bacterial Agents/isolation & purification , Bacteria/metabolism , Colony Count, Microbial , Fungi/metabolism , Anti-Bacterial Agents/metabolism , Anti-Bacterial Agents/pharmacology
3.
Braz. j. microbiol ; 49(1): 169-176, Jan.-Mar. 2018. tab, graf
Article in English | LILACS | ID: biblio-889211

ABSTRACT

ABSTRACT Major health challenges as the increasing number of cases of infections by antibiotic multiresistant microorganisms and cases of Alzheimer's disease have led to searching new control drugs. The present study aims to verify a new way of obtaining bioactive extracts from filamentous fungi with potential antimicrobial and acetylcholinesterase inhibitory activities, using epigenetic modulation to promote the expression of genes commonly silenced. For such finality, five filamentous fungal species (Talaromyces funiculosus, Talaromyces islandicus, Talaromyces minioluteus, Talaromyces pinophilus, Penicillium janthinellum) were grown or not with DNA methyltransferases inhibitors (procainamide or hydralazine) and/or a histone deacetylase inhibitor (suberohydroxamic acid). Extracts from T. islandicus cultured or not with hydralazine inhibited Listeria monocytogenes growth in 57.66 ± 5.98% and 15.38 ± 1.99%, respectively. Increment in inhibition of acetylcholinesterase activity was observed for the extract from P. janthinellum grown with procainamide (100%), when compared to the control extract (39.62 ± 3.76%). Similarly, inhibition of acetylcholinesterase activity increased from 20.91 ± 3.90% (control) to 92.20 ± 3.72% when the tested extract was obtained from T. pinophilus under a combination of suberohydroxamic acid and procainamide. Concluding, increases in antimicrobial activity and acetylcholinesterase inhibition were observed when fungal extracts in the presence of DNA methyltransferases and/or histone deacetylase modulators were tested.


Subject(s)
Anti-Bacterial Agents/pharmacology , Cholinesterase Inhibitors/pharmacology , Penicillium/chemistry , Talaromyces/chemistry , Acetylcholinesterase/chemistry , Acetylcholinesterase/metabolism , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/metabolism , Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , Cholinesterase Inhibitors/chemistry , Cholinesterase Inhibitors/metabolism , Chromatin/metabolism , Listeria monocytogenes/drug effects , Listeria monocytogenes/enzymology , Listeria monocytogenes/growth & development , Penicillium/metabolism , Talaromyces/metabolism
4.
Braz. j. microbiol ; 48(4): 809-814, Oct.-Dec. 2017. graf
Article in English | LILACS | ID: biblio-889176

ABSTRACT

ABSTRACT This study aimed to describe a Bacillus subtilis expression system based on genetically modified B. subtilis. Abaecin, an antimicrobial peptide obtained from Apis mellifera, can enhance the effect of pore-forming peptides from other species on the inhibition of bacterial growth. For the exogenous expression, the abaecin gene was fused with a tobacco etch virus protease cleavage site, a promoter Pglv, and a mature beta-glucanase signal peptide. Also, a B. subtilis expression system was constructed. The recombinant abaecin gene was expressed and purified as a recombinant protein in the culture supernatant. The purified abaecin did not inhibit the growth of Escherichia coli strain K88. Cecropin A and hymenoptaecin exhibited potent bactericidal activities at concentrations of 1 and 1.5 µM. Combinatorial assays revealed that cecropin A and hymenoptaecin had sublethal concentrations of 0.3 and 0.5 µM. This potentiating functional interaction represents a promising therapeutic strategy. It provides an opportunity to address the rising threat of multidrug-resistant pathogens that are recalcitrant to conventional antibiotics.


Subject(s)
Antimicrobial Cationic Peptides/genetics , Antimicrobial Cationic Peptides/metabolism , Bacillus subtilis/genetics , Genetic Vectors/genetics , Insect Proteins/genetics , Insect Proteins/metabolism , Anti-Bacterial Agents/isolation & purification , Anti-Bacterial Agents/metabolism , Anti-Bacterial Agents/pharmacology , Antimicrobial Cationic Peptides/isolation & purification , Antimicrobial Cationic Peptides/pharmacology , Bacillus subtilis/metabolism , Escherichia coli/drug effects , Escherichia coli/growth & development , Gene Expression , Genetic Vectors/metabolism , Insect Proteins/isolation & purification , Insect Proteins/pharmacology , Protein Engineering , Protein Transport , Recombinant Proteins/genetics , Recombinant Proteins/isolation & purification , Recombinant Proteins/metabolism , Recombinant Proteins/pharmacology
5.
Electron. j. biotechnol ; 30: 39-47, nov. 2017. tab, graf
Article in English | LILACS | ID: biblio-1021362

ABSTRACT

Background: Juvenile Yoshitomi tilapia is often infected by pathogens and results in low-level survival rate. Bacillus subtilis, as a probiotic, may have beneficial effects on Y. tilapia with compound 1-deoxynojirimycin (DNJ), which has antibacterial activities. The effects of dietary probiotic supplementation on Y. tilapias were evaluated. Results: Juvenile Y. tilapia was fed with B. subtilis for 56 d. Y. tilapia was infected by Aeromonas hydrophila and survival rate was compared. Dietary B. subtilis increased weight gain rate, specific growth, food conversion ratios and food intake rate of Y. tilapia. The diet improved the cumulative survival rate (CSR) of juvenile Y. tilapia when the concentration of B. subtilis was more than 2.05 × 1010 cfu/kg and CSR reached a maximum rate when the concentration of bacillus was 4.23 × 1010 (P b 0.05). Meanwhile, B. subtilis improved total antioxidant capacity (TAC), spleen index, the activities of serum lysozyme, alkaline phosphatase (ALP), superoxide dismutase (SOD) and catalase (CAT) (P b 0.05). In contrast, B. subtilis reduced serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), malondialdehyde (MDA) and C3 complement (P b 0.05). DNJ was isolated from secondary metabolisms and proved to increase the levels of SOD, CAT and reduce the levels of AST, ALT and MDA at cell levels. After A. hydrophila infection, DNJ prevented the reduction in survival rate of Y. tilapia (P b 0.05). Conclusions: 1-Deoxynojirimycin from Bacillus subtilis can be used to improve the growth performance of juvenile Y. tilapia by affecting its antioxidant and antibacterial activities.


Subject(s)
1-Deoxynojirimycin/administration & dosage , Tilapia/growth & development , Tilapia/metabolism , Probiotics/administration & dosage , Superoxide Dismutase/drug effects , Survival , Aeromonas hydrophila/metabolism , Aquaculture , Alkaline Phosphatase/drug effects , Anti-Bacterial Agents/metabolism , Antioxidants/metabolism
6.
Braz. j. microbiol ; 47(3): 691-696, July-Sept. 2016. tab
Article in English | LILACS | ID: lil-788958

ABSTRACT

ABSTRACT This study highlights the prevalence of aminoglycoside-modifying enzyme genes and virulence determinants among clinical enterococci with high-level aminoglycoside resistance in Inner Mongolia, China. Screening for high-level aminoglycoside resistance against 117 enterococcal clinical isolates was performed using the agar-screening method. Out of the 117 enterococcal isolates, 46 were selected for further detection and determination of the distribution of aminoglycoside-modifying enzyme-encoding genes and virulence determinants using polymerase chain reaction -based methods. Enterococcus faecium and Enterococcus faecalis were identified as the species of greatest clinical importance. The aac(6')-Ie-aph(2")-Ia and ant(6')-Ia genes were found to be the most common aminoglycoside-modifying enzyme genes among high-level gentamicin resistance and high-level streptomycin resistance isolates, respectively. Moreover, gelE was the most common virulence gene among high-level aminoglycoside resistance isolates. Compared to Enterococcus faecium, Enterococcus faecalis harbored multiple virulence determinants. The results further indicated no correlation between aminoglycoside-modifying enzyme gene profiles and the distribution of virulence genes among the enterococcal isolates with high-level gentamicin resistance or high-level streptomycin resistance evaluated in our study.


Subject(s)
Male , Female , Gene Expression Regulation, Bacterial/drug effects , Gene Expression Regulation, Enzymologic/drug effects , Enterococcus/drug effects , Enterococcus/physiology , Drug Resistance, Bacterial , Aminoglycosides/metabolism , Aminoglycosides/pharmacology , Virulence/genetics , Microbial Sensitivity Tests , China/epidemiology , Prevalence , Gram-Positive Bacterial Infections/microbiology , Gram-Positive Bacterial Infections/epidemiology , Enterococcus/metabolism , Genes, Bacterial , Anti-Bacterial Agents/metabolism
7.
Braz. j. microbiol ; 47(2): 381-388, Apr.-June 2016. tab, graf
Article in English | LILACS | ID: lil-780828

ABSTRACT

Abstract Pan-drug resistant Gram-negative bacteria, being resistant to most available antibiotics, represent a huge threat to the medical community. Colistin is considered the last therapeutic option for patients in hospital settings. Thus, we were concerned in this study to demonstrate the membrane permeabilizing activity of colistin focusing on investigating its efficiency toward those pan-drug resistant isolates which represent a critical situation. We determined the killing dynamics of colistin against pan-drug resistant isolates. The permeability alteration was confirmed by different techniques as: leakage, electron microscopy and construction of an artificial membrane model; liposomes. Moreover, selectivity of colistin against microbial cells was also elucidated. Colistin was proved to be rapid bactericidal against pan-drug resistant isolates. It interacts with the outer bacterial membrane leading to deformation of its outline, pore formation, leakage of internal contents, cell lysis and finally death. Furthermore, variations in membrane composition of eukaryotic and microbial cells provide a key for colistin selectivity toward bacterial cells. Colistin selectively alters membrane permeability of pan-drug resistant isolates which leads to cell lysis. Colistin was proved to be an efficient last line treatment for pan-drug resistant infections which are hard to treat.


Subject(s)
Humans , Cell Membrane/metabolism , Gram-Negative Bacterial Infections/microbiology , Colistin/metabolism , Drug Resistance, Multiple, Bacterial , Gram-Negative Bacteria/metabolism , Anti-Bacterial Agents/metabolism , Microbial Sensitivity Tests , Cell Membrane/drug effects , Cell Membrane Permeability , Gram-Negative Bacterial Infections/drug therapy , Colistin/pharmacology , Gram-Negative Bacteria/isolation & purification , Gram-Negative Bacteria/drug effects , Gram-Negative Bacteria/ultrastructure , Anti-Bacterial Agents/pharmacology
8.
Braz. j. microbiol ; 46(3): 825-834, July-Sept. 2015. tab, ilus
Article in English | LILACS | ID: lil-755824

ABSTRACT

Lactobacillus sakei subsp. sakei 2a is a bacteriocinogenic lactic acid bacterium isolated from Brazilian pork sausage, capable of inhibiting the growth of microbial pathogens, mainly Listeria monocytogenes. In order to optimize bacteriocin production for industrial applications, this study evaluated the effect of supplementation of MRS broth with glucose, Tween 20, Tween 80, sodium citrate, potassium chloride and cysteine, and effect of the initial pH and temperature of incubation of the medium on production of bacteriocins by L. sakei 2a. Adding glucose and Tween 20 to the medium, an initial pH of 5.0 or 5.5, and incubation temperatures of 25 °C or 30 °C resulted to the highest bacteriocin yields. Thus, a 24 factorial design with the four variables was performed, and statistical analysis showed that it was an adequate model (R2 = 0.8296). In the studied range, the four parameters significantly influenced bacteriocin production, with the maximum yield produced at an initial pH between 5.5 and 7.0, a temperature between 25 and 30 °C and supplementation of the MRS broth with glucose from 3.25 to 6.0 g L−1 and Tween 20 from 0.575 to 1.15% (v/v). Response Surface Methodology analysis indicated that the highest bacteriocin production (12800 AU mL−1) occurred in the MRS broth supplemented with 5.5 g L−1 glucose and 1.05% Tween 20 at an initial pH of 6.28 and an incubation temperature of 25 °C. The amount of bacteriocin produced in commercial MRS broths under the same conditions was only 5600AU mL−1.

.


Subject(s)
Anti-Bacterial Agents/metabolism , Bacteriocins/metabolism , Culture Media/metabolism , Lactobacillus/growth & development , Lactobacillus/metabolism , Brazil , Glucose/metabolism , Lactobacillus/classification , Microbial Sensitivity Tests , Polysorbates/metabolism , Red Meat/microbiology , Surface Properties , Temperature
9.
Braz. j. microbiol ; 46(1): 149-154, 05/2015. tab
Article in English | LILACS | ID: lil-748264

ABSTRACT

Public health is facing a new challenge due to the alarming increase in bacterial resistance to most of the conventional antibacterial agents. It has been found that only minor cell damage is caused when exposed to sub-lethal levels of antimicrobial. Biofilms can play an important role in producing resistance, which is developed to reservoirs of pathogens in the hospital and cannot be easily removed. The aim of this study was to test whether the sub-lethal dose of antibiotics can induce biofilm formation of P. aeruginosa following incubating in the presence and absence of chlorhexidine. Standard antibiotic-micro broth 96-flat well plates were used for determination of MIC and biofilm assay. The adherence degree of biofilm was determined by estimation of OD630 nm values using ELISA reader. The mean 22 isolates of P. aeruginosa growing in culture with presence and absence of chlorhexidine, could exhibited the significant (p < 0.001) proportion of adherence followed incubation in sub minimal inhibitory concentrations (Sub-MIC) of cefotaxim, amoxicillin, and azithromycin in comparison with control (antibiotic-free broth), while the sub-MIC of ciprofloxacin revealed significant inhibition of biofilm. Conclusion: Incubating the isolates of P. aeruginosa to sub-MIC of antibiotics exhibited induction of biofilm in the presence of chlorhexidine.


Subject(s)
Anti-Bacterial Agents/metabolism , Anti-Infective Agents/metabolism , Biofilms/drug effects , Biofilms/growth & development , Chlorhexidine/metabolism , Growth Substances/metabolism , Pseudomonas aeruginosa/drug effects , Microbial Sensitivity Tests , Pseudomonas aeruginosa/physiology
10.
Braz. j. microbiol ; 45(4): 1221-1227, Oct.-Dec. 2014. ilus, graf, tab
Article in English | LILACS | ID: lil-741271

ABSTRACT

Metal nanoparticle synthesis is an interesting area in nanotechnology due to their remarkable optical, magnetic, electrical, catalytic and biomedical properties, but there needs to develop clean, non-toxic and environmental friendly methods for the synthesis and assembly of nanoparticles. Biological agents in the form of microbes have emerged up as efficient candidates for nanoparticle synthesis due to their extreme versatility to synthesize diverse nanoparticles with varying size and shape. In the present study, an eco favorable method for the biosynthesis of silver nanoparticles using marine bacterial isolate has been attempted. Very interestingly, molecular identification proved it as a strain of Ochrobactrum anhtropi. In addition, the isolate was found to have the potential to form silver nanoparticles intracellularly at room temperature within 24 h. The biosynthesized silver nanoparticles were characterized by UV-Vis spectroscopy, transmission electron microscope (TEM) and scanning electron microscope (SEM). The UV-visible spectrum of the aqueous medium containing silver nanoparticles showed a peak at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. The SEM and TEM micrographs revealed that the synthesized silver nanoparticles were spherical in shape with a size range from 38 nm - 85 nm. The silver nanoparticles synthesized by the isolate were also used to explore its antibacterial potential against pathogens like Salmonella Typhi, Salmonella Paratyphi, Vibrio cholerae and Staphylococcus aureus.


Subject(s)
Anti-Bacterial Agents/pharmacology , Nanoparticles/metabolism , Ochrobactrum/metabolism , Silver/pharmacology , Anti-Bacterial Agents/metabolism , Aquatic Organisms/classification , Aquatic Organisms/genetics , Aquatic Organisms/isolation & purification , Aquatic Organisms/metabolism , Cluster Analysis , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Gram-Negative Bacteria/drug effects , Microscopy, Electron , Nanoparticles/chemistry , Nanoparticles/ultrastructure , Ochrobactrum/classification , Ochrobactrum/genetics , Ochrobactrum/isolation & purification , Phylogeny , /genetics , Sequence Analysis, DNA , Spectrum Analysis , Silver/metabolism , Staphylococcus aureus/drug effects , Temperature , Time Factors
11.
Braz. j. microbiol ; 45(4): 1309-1315, Oct.-Dec. 2014. ilus, graf, tab
Article in English | LILACS | ID: lil-741281

ABSTRACT

The present study proposed the isolation of arsenic resistant bacteria from wastewater. Only three bacterial isolates (MNZ1, MNZ4 and MNZ6) were able to grow in high concentrations of arsenic. The minimum inhibitory concentrations of arsenic against MNZ1, MNZ4 and MNZ6 were 300 mg/L, 300 mg/L and 370 mg/L respectively. The isolated strains showed maximum growth at 37 ºC and at 7.0 pH in control but in arsenite stress Luria Bertani broth the bacterial growth is lower than control. All strains were arsenite oxidizing. All strains were biochemically characterized and ribotyping (16S rRNA) was done for the purpose of identification which confirmed that MNZ1 was homologous to Enterobacter sp. while MNZ4 and MNZ6 showed their maximum homology with Klebsiella pneumoniae. The protein profiling of these strains showed in arsenic stressed and non stressed conditions, so no bands of induced proteins appeared in stressed conditions. The bacterial isolates can be exploited for bioremediation of arsenic containing wastes, since they seem to have the potential to oxidize the arsenite (more toxic) into arsenate (less toxic) form.


Subject(s)
Anti-Bacterial Agents/metabolism , Arsenic/metabolism , Drug Resistance, Bacterial , Enterobacter/drug effects , Klebsiella pneumoniae/drug effects , Waste Water/microbiology , Arsenites/metabolism , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Enterobacter/classification , Enterobacter/growth & development , Enterobacter/isolation & purification , Hydrogen-Ion Concentration , Klebsiella pneumoniae/classification , Klebsiella pneumoniae/growth & development , Klebsiella pneumoniae/isolation & purification , Microbial Sensitivity Tests , Oxidation-Reduction , Proteome/analysis , Ribotyping , /genetics , Temperature
12.
Braz. j. microbiol ; 45(4): 1541-1550, Oct.-Dec. 2014. tab
Article in English | LILACS | ID: lil-741311

ABSTRACT

Lactic acid bacteria capable of producing bacteriocins and presenting probiotic potential open innovative technological applications in the dairy industry. In this study, a bacteriocinogenic strain (Lactococcus lactis subsp. lactis DF4Mi) was isolated from goat milk, and studied for its antimicrobial activity. The bacteriocin presented a broad spectrum of activity, was sensitive to proteolytic enzymes, resistant to heat and pH extremes, and not affected by the presence of SDS, Tween 20, Tween 80, EDTA or NaCl. Bacteriocin production was dependent on the components of the culture media, especially nitrogen source and salts. When tested by PCR, the bacteriocin gene presented 100% homology to nisin Z gene. These properties indicate that this L. lactis subsp. lactis DF4Mi can be used for enhancement of dairy foods safety and quality.


Subject(s)
Animals , Anti-Bacterial Agents/metabolism , Bacteriocins/metabolism , Lactococcus lactis/metabolism , Milk/microbiology , Amino Acid Sequence , Anti-Bacterial Agents/chemistry , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Bacteriocins/chemistry , Bacteriocins/genetics , Culture Media/chemistry , Detergents , DNA, Bacterial/genetics , Goats , Hydrogen-Ion Concentration , Lactococcus lactis/growth & development , Molecular Sequence Data , Polymerase Chain Reaction , Protein Stability , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Sodium Chloride/metabolism , Temperature
13.
Biomédica (Bogotá) ; 34(supl.1): 16-22, abr. 2014. tab
Article in Spanish | LILACS | ID: lil-712417

ABSTRACT

Introducción. Las betalactamasas de espectro extendido (BLEE) son un fenómeno de resistencia emergente de particular incidencia en América Latina. En Colombia existe poca información sobre los factores de riesgo asociados con su adquisición. Objetivo. Determinar los factores de riesgo que están asociados a la infección o colonización por Escherichia coli o Klebsiella pneumoniae productoras de BLEE en pacientes mayores de 18 años. Materiales y métodos. Se llevó a cabo un estudio de casos y controles con relación 1:1 en pacientes con aislamientos de E. coli o K. pneumoniae productoras de BLEE en cualquier tipo de muestra durante el periodo de enero de 2009 a noviembre de 2011 en el Hospital Universitario de San José. Resultados. Se estudiaron 110 casos y 110 controles; 62,7 % correspondió a E. coli y 37,3 %, a K. pneumoniae . Como factores de riesgo independiente en el análisis multivariado se encontraron la insuficiencia renal crónica (OR=2,99; IC 95%, 1,10-8,11; p=0,031), la cirugía urológica (OR=4,78; IC 95%, 1,35-16,87; p=0,015), el antecedente de uso de antibióticos en los tres meses anteriores (OR=2,24; IC 95%, 1,09-4,60; p=0,028), el origen hospitalario de la infección (OR=2,92; IC 95%, 1,39-6,13; p=0,004) y la hospitalización previa (OR=1,59; IC 95%, 1,03-2,46; p=0,036). Conclusión. Anticiparse al patrón de resistencia del microorganismo que infecta a un paciente con base en los factores de riesgo asociados permitiría la elección de un tratamiento antibiótico empírico apropiado, con el fin de lograr la disminución de la morbimortalidad de los pacientes.


.


Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Anti-Bacterial Agents/pharmacology , Drug Resistance, Multiple, Bacterial , Escherichia coli Infections/microbiology , Escherichia coli/enzymology , Klebsiella Infections/microbiology , Klebsiella pneumoniae/enzymology , beta-Lactams/pharmacology , Anti-Bacterial Agents/metabolism , Case-Control Studies , Colombia , Cross Infection/epidemiology , Cross Infection/microbiology , Drug Resistance, Multiple, Bacterial/genetics , Escherichia coli Infections/epidemiology , Escherichia coli/drug effects , Escherichia coli/genetics , Escherichia coli/isolation & purification , Immunocompromised Host , Klebsiella Infections/epidemiology , Klebsiella pneumoniae/drug effects , Klebsiella pneumoniae/genetics , Klebsiella pneumoniae/isolation & purification , Postoperative Complications/microbiology , Retrospective Studies , Risk Factors , Tertiary Care Centers , beta-Lactam Resistance/genetics , beta-Lactams/metabolism
14.
Clin. biomed. res ; 34(3): 281-286, 2014. tab, graf
Article in English | LILACS | ID: biblio-834465

ABSTRACT

Introduction: Enterococci have become the third leading cause of nosocomial bacteraemia, an infection which is significantly associated with the risk of developing infective endocarditis. Linezolid provides high rates of clinical cure and microbiologic success in complicated infections due to Enterococcus spp. However, several instances of emergence of resistance during linezolid treatment have been reported. The aim of this study was evaluate the activity of tigecycline against linezolidintermediate (LIE) and linezolid-resistant enterococcus faecalis(LRE) by the timekill assay. Methods: Five isolates of LRE and two isolates of LIE were used in this study. Minimum inhibitory concentration (MIC) was determined by broth dilution following the guidelines from the Clinical and Laboratory Standards Institute (CLSI). Time-kill assay was employed to access the in vitro response profile of tigecycline. Results: All seven isolates presented MIC of 0.125 ìg/mL. Tigecycline activity was individually evaluated according to CLSI criteria. This antibiotic showed bactericidal activity against three of the five isolates of LRE and bacteriostatic activity against the other isolates. Conclusions: Tigecycline presented both bacteriostatic and bactericidal activity against tested isolates, which is an important data that must be considered for new studies.


Subject(s)
Humans , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/metabolism , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/chemical synthesis , Enterococcus faecalis , Minocycline/analogs & derivatives , Minocycline/pharmacology , Culture Media
15.
Braz. j. microbiol ; 44(4): 1007-1034, Oct.-Dec. 2013. ilus, graf, tab
Article in English | LILACS | ID: lil-705250

ABSTRACT

The discovery of secondary metabolites produced by microorganisms (e.g., penicillin in 1928) and the beginning of their industrial application (1940) opened new doors to what has been the main medication source for the treatment of infectious diseases and tumors. In fact, approximately 80 years after the discovery of the first antibiotic compound, and despite all of the warnings about the failure of the "goose that laid the golden egg," the potential of this wealth is still inexorable: simply adjust the focus from "micro" to "nano", that means changing the look from microorganisms to nanograms of DNA. Then, the search for new drugs, driven by genetic engineering combined with metagenomic strategies, shows us a way to bypass the barriers imposed by methodologies limited to isolation and culturing. However, we are far from solving the problem of supplying new molecules that are effective against the plasticity of multi- or pan-drug-resistant pathogens. Although the first advances in genetic engineering date back to 1990, there is still a lack of high-throughput methods to speed up the screening of new genes and design new molecules by recombination of pathways. In addition, it is necessary an increase in the variety of heterologous hosts and improvements throughout the full drug discovery pipeline. Among numerous studies focused on this subject, those on polyketide antibiotics stand out for the large technical-scientific efforts that established novel solutions for the transfer/engineering of major metabolic pathways using transposons and other episomes, overcoming one of the main methodological constraints for the heterologous expression of major pathways. In silico prediction analysis of three-dimensional enzymatic structures and advances in sequencing technologies have expanded access to the metabolic potential of microorganisms.


Subject(s)
Animals , Humans , Anti-Bacterial Agents/metabolism , Biosynthetic Pathways/genetics , Biotechnology/methods , Drug Discovery/methods , Metagenomics/methods , Polyketides/metabolism , Anti-Bacterial Agents/isolation & purification , Biotechnology/trends , Drug Discovery/trends , Metabolic Engineering/methods , Metabolic Engineering/trends , Metagenomics/trends , Polyketides/isolation & purification , Secondary Metabolism
16.
Indian J Med Microbiol ; 2012 Jul-Sept; 30(3): 302-307
Article in English | IMSEAR | ID: sea-143974

ABSTRACT

Purpose: Many isolates of Serratia marcescens, a well-known opportunistic pathogen, can be multidrug resistant. Fluoroquinolones are among the most important groups of antibiotics used for treatment of these organisms. However, fluoroquinolone resistance among S. marcescens isolates is fast increasing. Drug extrusion through efflux pumps like SdeAB/ HasF is one of the major mechanisms of resistance to fluoroquinolones. This study was carried out to analyze, through gene expression analysis of sdeB, the relative contribution of this mechanism toward fluoroquinolone resistance in clinical isolates of Serratia. Materials and Methods: Total RNA from 45 clinical isolates of S. marcescens was isolated. Quantitative real-time RT PCR was performed on the extracted RNA to study the gene expression of sdeB and was normalized to the sdeB expression in the standard strain of S. marcescens. Results: Of the 45 isolates analyzed, sdeB expression was found to be elevated in 20 isolates (44%). Of these 20 isolates, eight (40%) were fully resistant to at least one of the fluoroquinolones studied. Conversely, of the 20 isolates that over-expressed sdeB, 12 (60%) were fully sensitive to all fluoroquinolones tested. Conclusions: Drug efflux pumps are an important means of fluoroquinolone resistance among clinically important species ofSerratia. The expression of these pumps can be up-regulated in the presence of antibiotics and have the potential for changing the phenotype from sensitive to resistant, thus contributing to therapeutic failures.


Subject(s)
Anti-Bacterial Agents/metabolism , Anti-Bacterial Agents/pharmacology , Drug Resistance, Multiple, Bacterial , Fluoroquinolones/metabolism , Fluoroquinolones/pharmacology , Gene Expression Profiling , Humans , Membrane Transport Proteins/biosynthesis , Membrane Transport Proteins/genetics , Real-Time Polymerase Chain Reaction , Serratia Infections/microbiology , Serratia marcescens/drug effects , Serratia marcescens/genetics , Serratia marcescens/isolation & purification
17.
Electron. j. biotechnol ; 15(2): 3-3, Mar. 2012. ilus, tab
Article in English | LILACS | ID: lil-640538

ABSTRACT

Different strategies have been used to overcome the difficulties to produce antimicrobial peptides. Here we used Intein Mediated Purification with an Affinity Chitin-binding Tag (IMPACT-System, New England Biolabs) for the expression of the antimicrobial peptide cecropin to reduce its sensitivity to intracellular proteases and use its inducible self-cleaving capability to remove the carrier. Cecropin was cloned into suitable expression vector pTYB11, and expression induced by IPTG in Escherichia coli ER2566. The use of 22ºC induction allowed the expression of cecropin with its intein carrier in soluble form. Cell extracts were purified by chitin affinity chromatography and intein-mediated splicing of the target protein was achieved by thiol addition, obtaining a final yield of 2.5 mg cecropin/l. Cecropin cleaved from the intein had its proper biologically active form, showing a micromolar antimicrobial activity against Vibrio ordalii, Vibrio alginolyticus and Escherichia coli.


Subject(s)
Humans , Anti-Bacterial Agents/metabolism , Cecropins/metabolism , Escherichia coli , Blotting, Western , Chromatography, Affinity , Chromatography, High Pressure Liquid , Cloning, Molecular , Gene Fusion , Inteins , Antimicrobial Cationic Peptides/metabolism , Recombinant Proteins
18.
Rev. Soc. Bras. Med. Trop ; 44(4): 441-446, July-Aug. 2011. tab
Article in English | LILACS | ID: lil-596592

ABSTRACT

INTRODUCTION: Extended spectrum β-lactamases (ESBLs) are enzymes that degrade β-lactam antibiotics and have been reported to be an important cause of nosocomial infection in worldwide. METHODS: During 2009, 659 enterobacteria strains were isolated from different clinical specimens and tested for ESBL production. The disk approximation test, combined disk method and addition of clavulanic acid were used for phenotypic detection of the ESBL-producing strains and PCR for detection of the blaTEM and blaCTX-M genes. RESULTS: Among the isolates, 125 were ESBL producers. The blaCTX-M and blaTEM genes were detected in 90.4% and 75% of the strains, respectively. Most strains were isolated from urine. Klebsiella pneumoniae was the most prevalent organism. Microorganisms presented high resistance to the antibiotics. CONCLUSIONS: These results support the need for extending ESBL detection methods to different pathogens of the Enterobacteriaceae family because these methods are only currently standardized by the CLSI for Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca and Proteus mirabilis. Carbapenems were the antibiotic class of choice for the treatment of infections caused by ESBL-producing Enterobacteriaceae.


INTRODUÇÃO: As β-lactamases de espectro ampliado (ESBLs) são enzimas que degradam os antibióticos β-lactâmicos e têm sido reportadas como uma importante causa de infecções hospitalares em todo o mundo. MÉTODOS: Em 2009, 659 enterobactérias foram isoladas de diferentes espécimes clínicos e testadas quanto à produção de ESBL. Os testes de aproximação do disco, disco combinado e adição do ácido clavulânico foram utilizados na detecção fenotípica das amostras produtoras de ESBL e PCR para a detecção dos genes blaTEM e blaCTX-M. RESULTADOS: Entre os isolados, 125 foram produtores de ESBL. Os genes blaCTX-M e blaTEM foram detectados em 90,4% e 75% das amostras, respectivamente. Com relação ao espécime clínico, a maioria das amostras foi isolada de urina. Klebsiella pneumoniae foi a espécie mais prevalente e o teste de susceptibilidade antimicrobiana mostrou uma elevada resistência dos microorganismos aos antibióticos testados. CONCLUSÕES: Estes resultados suportam a necessidade de se ampliar os métodos de detecção das ESBLs para os diferentes patógenos da família Enterobacteriaceae, uma vez que esses métodos estão padronizados pelo CLSI apenas para Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca e Proteus mirabilis. Os carbapenens foram os antibióticos de escolha para o tratamento de infecções causadas por enterobactérias produtoras de ESBL.


Subject(s)
Humans , Anti-Bacterial Agents/pharmacology , Cross Infection/microbiology , Enterobacteriaceae Infections/microbiology , Enterobacteriaceae/enzymology , beta-Lactam Resistance/genetics , beta-Lactamases/biosynthesis , Anti-Bacterial Agents/metabolism , Brazil , Enterobacteriaceae/drug effects , Enterobacteriaceae/genetics , Enterobacteriaceae/isolation & purification , Microbial Sensitivity Tests , Phenotype , beta-Lactam Resistance/drug effects
19.
Indian J Med Microbiol ; 2011 Jul-Sept; 29(3): 249-253
Article in English | IMSEAR | ID: sea-143825

ABSTRACT

Purpose: The newly emerging form of the so-called New Delhi Metallo-beta-lactamases (NDM-1) has been reported recently from patients worldwide and broadly thought as a potential source for the major global health problem. Thus, it is important to study the epidemiology of the so-called NDM-1 harbouring bacteria to prevent its further spread and to place effective control measures. The present study describes the use of the real-time polymerase chain reaction (PCR) assay for the detection of the bla NDM-1 gene using TaqMan probes among clinical isolates. Materials and Methods: Clinical isolates of Escherichia coli (11 strains), Klebsiella pneumoniae (17 strains) and Acinetobacter baumannii (six strains) that were resistant to either of the carbapenems (meropenem or imipenem) were included in the study. The presence of carbapenemases in such strains was confirmed using the modified Hodge test. A real-time PCR assay was optimized for the detection of NDM-1 using a cloned synthetic gene fragment followed by testing of the clinical isolates. The findings were further confirmed using PCR and gene sequencing. Results: TaqMan probe assay displayed a good detection limit with analytical sensitivity of the assay up to 10 copies of bla NDM-1 gene per reaction. The isolates of E. coli and K. pneumoniae revealed narrow range crossing point values (Cp values) between (12-17) cycles (mean Cp value 14), indicating number of bla NDM-1 gene copies of 106-108. The wider range of Cp values (15-34) cycles with a higher mean Cp value (23.6) was observed in A. baumannii with number of bla NDM-1 gene copies of 103-108. Conclusions: The study demonstrates that real-time PCR assay based on TaqMan chemistry is a useful technique for the detection of bla NDM-1 harbouring clinical isolates of E. coli, K. pneumoniae and A. baumannii. The assay has great precision in measuring the number of bla NDM-1 gene copies per specimen of DNA.


Subject(s)
Acinetobacter baumannii/drug effects , Acinetobacter baumannii/genetics , Acinetobacter baumannii/isolation & purification , Anti-Bacterial Agents/metabolism , Bacteriological Techniques/methods , Carbapenems/metabolism , Escherichia coli/drug effects , Escherichia coli/genetics , Escherichia coli/isolation & purification , Genes, Bacterial , Humans , Klebsiella pneumoniae/drug effects , Klebsiella pneumoniae/genetics , Klebsiella pneumoniae/isolation & purification , Real-Time Polymerase Chain Reaction/methods , beta-Lactam Resistance , beta-Lactamases/genetics , beta-Lactamases/metabolism
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