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1.
Environ Microbiol ; 26(5): e16654, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38779707

RESUMO

Vibrios, a group of bacteria that are among the most abundant in marine environments, include several species such as Vibrio cholerae and Vibrio parahaemolyticus, which can be pathogenic to humans. Some species of Vibrio contain prophages within their genomes. These prophages can carry genes that code for toxins, such as the zonula occludens toxin (Zot), which contribute to bacterial virulence. Understanding the association between different Vibrio species, prophages and Zot genes can provide insights into their ecological interactions. In this study, we evaluated 4619 Vibrio genomes from 127 species to detect the presence of prophages carrying the Zot toxin. We found 2030 potential prophages with zot-like genes in 43 Vibrio species, showing a non-random association within a primarily modular interaction network. Some prophages, such as CTX or Vf33, were associated with specific species. In contrast, prophages phiVCY and VfO3K6 were found in 28 and 20 Vibrio species, respectively. We also identified six clusters of Zot-like sequences in prophages, with the ZOT2 cluster being the most frequent, present in 34 Vibrio species. This analysis helps to understand the distribution patterns of zot-containing prophages across Vibrio genomes and the potential routes of Zot-like toxin dissemination.


Assuntos
Genoma Bacteriano , Prófagos , Vibrio , Prófagos/genética , Vibrio/genética , Vibrio/virologia , Toxinas Bacterianas/genética , Proteínas de Bactérias/genética , Vibrio parahaemolyticus/genética , Vibrio parahaemolyticus/virologia , Filogenia , Endotoxinas
2.
J Invertebr Pathol ; 194: 107829, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36167186

RESUMO

Photorhabdus insect related proteins A & B (PirA, PirB) from Photorhabdus and Xenorhabdus bacteria exhibit both oral and injectable toxicity against lepidopteran and dipteran insect pest. The pirA, pirAt (encoding 6 N-terminal truncated PirA), pirB genes, pirA-pirB (with ERIC sequences), pirA-pirB-mERIC (modified pirA-pirB with mutated ERIC sequences) and polycistronic-pirAB were cloned and expressed in Escherichia coli. However, PirA protein was expressed in insoluble form and therefore the pirA gene was modified to produce PirAt. Moreover, pirA-pirB-mERIC, polycistronic-pirAB and co-transformed pirA/pirB genes were not expressed in the studied prokaryotic expression systems. None of the single purified proteins or mixtures of the individually expressed and purified proteins were toxic to mosquito larvae of Aedes aegypti and Culex quinquefasciatus. However, PirA-PirB protein mixtures purified from pirA-pirB operon plasmid were toxic to A. aegypti and C. quinquefasciatus larvae with LC50 values of 991 and 614 ng/ml, respectively. The presence of ERIC sequences between the two orfs of the pirA-pirB operon could help to obtain the proteins in biologically active form. Further, results confirm that PirA-PirB proteins of P. akhurstii subsp. akhurstii K-1 are binary insecticidal toxins and ERIC sequences could play an important role in expression of Pir proteins. Reports of biophysical characterization of individually purified PirAt, PirB and expressed PirA-PirB toxin mixture could provide the structural insight into these proteins.


Assuntos
Toxinas Bacterianas , Photorhabdus , Xenorhabdus , Animais , Proteínas de Bactérias/química , Toxinas Bacterianas/química , Toxinas Bacterianas/genética , Toxinas Bacterianas/toxicidade , Escherichia coli , Proteínas de Insetos/metabolismo , Larva/metabolismo , Photorhabdus/metabolismo , Xenorhabdus/genética , Xenorhabdus/metabolismo
3.
Toxins (Basel) ; 14(5)2022 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-35622541

RESUMO

Invasive nostocalean cyanobacteria (INC) were first reported in tropical regions and are now globally spreading rapidly due to climate change, appearing in temperate regions. INC require continuous monitoring for water resource management because of their high toxin production potential. However, it is difficult to analyze INC under a microscope because of their morphological similarity to nostocalean cyanobacteria such as the genus Aphanizomenon. This study calculates the gene copy number per cell for each target gene through quantitative gene analysis on the basis of genus-specific primers of genera Cylindrospermopsis, Sphaerospermopsis, and Cuspidothrix, and the toxin primers of anatoxin-a, saxitoxin, and cylindrospermopsin. In addition, quantitative gene analysis was performed at eight sites in the Nakdong River to assess the appearance of INC and their toxin production potential. Genera Cylindrospermopsis and Sphaerospermopsis did not exceed 100 cells mL-1 at the maximum, with a low likelihood of related toxin occurrence. The genus Cuspidothrix showed the highest cell density (1759 cells mL-1) among the INC. Nakdong River has potential for the occurrence of anatoxin-a through biosynthesis by genus Cuspidothrix because the appearance of this genus coincided with that of the anatoxin-a synthesis gene (anaF) and the detection of the toxin by ELISA.


Assuntos
Aphanizomenon , Toxinas Bacterianas , Cianobactérias , Cylindrospermopsis , Aphanizomenon/genética , Toxinas Bacterianas/análise , Toxinas Bacterianas/genética , Cianobactérias/genética , República da Coreia , Rios/microbiologia
4.
Am J Infect Control ; 47(12): 1415-1419, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31324491

RESUMO

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is common in medical institutions. We sought to examine the prevalence of S aureus on environmental surfaces in nursing homes and to obtain molecular information on contaminating strains. METHODS: A total of 259 environmental samples were collected from 7 different nursing homes in Northeast Ohio (NEO), from suburban, urban, and rural settings. The presence of the mecA and PVL genes was determined, and spa typing was performed in order to identify molecular types. RESULTS: The prevalence of S aureus was 28.6% (74/259). The prevalence of MRSA and methicillin-susceptible S aureus was 20.1% (52/259) and 8.5% (22/259), respectively. S aureus contamination in suburban, urban, and rural sites was 25.7% (38/148), 45.9% (34/74), and 5.4% (2/37), respectively. MRSA was detected in 16.9% (25/148) of suburban samples and 36.5% (27/74) of urban samples. No MRSA was found in rural samples. Nursing homes from urban areas had a significantly higher (P < .001) prevalence of S aureus compared to nursing homes from suburban and rural sites. Areas with high nurse touch rates were the most commonly contaminated. CONCLUSIONS: We found differences in the prevalence of S aureus and MRSA in nursing homes in different regions of NEO. Part of these differences may result from transfers from hospitals; the urban nursing homes had 4 to 15 hospitals nearby, whereas suburban and rural locations had 1 to 3 hospitals within the area.


Assuntos
Contaminação de Equipamentos/estatística & dados numéricos , Fômites/microbiologia , Instituição de Longa Permanência para Idosos , Staphylococcus aureus Resistente à Meticilina/genética , Casas de Saúde , Infecções Estafilocócicas/epidemiologia , Idoso , Idoso de 80 Anos ou mais , Antígenos de Bactérias/genética , Proteínas de Bactérias/genética , Toxinas Bacterianas/genética , Técnicas de Tipagem Bacteriana , Contaminação de Equipamentos/prevenção & controle , Exotoxinas/genética , Feminino , Humanos , Leucocidinas/genética , Assistência de Longa Duração/organização & administração , Masculino , Staphylococcus aureus Resistente à Meticilina/classificação , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Ohio/epidemiologia , Proteínas de Ligação às Penicilinas/genética , Prevalência , Serviços de Saúde Rural , Infecções Estafilocócicas/prevenção & controle , Infecções Estafilocócicas/transmissão , Serviços de Saúde Suburbana , Serviços Urbanos de Saúde
5.
PLoS Comput Biol ; 15(4): e1006946, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-31022176

RESUMO

Bacterial Toxin-Antitoxin systems (TAS) are involved in key biological functions including plasmid maintenance, defense against phages, persistence and virulence. They are found in nearly all phyla and classified into 6 different types based on the mode of inactivation of the toxin, with the type II TAS being the best characterized so far. We have herein developed a new in silico discovery pipeline named TASmania, which mines the >41K assemblies of the EnsemblBacteria database for known and uncharacterized protein components of type I to IV TAS loci. Our pipeline annotates the proteins based on a list of curated HMMs, which leads to >2.106 loci candidates, including orphan toxins and antitoxins, and organises the candidates in pseudo-operon structures in order to identify new TAS candidates based on a guilt-by-association strategy. In addition, we classify the two-component TAS with an unsupervised method on top of the pseudo-operon (pop) gene structures, leading to 1567 "popTA" models offering a more robust classification of the TAs families. These results give valuable clues in understanding the toxin/antitoxin modular structures and the TAS phylum specificities. Preliminary in vivo work confirmed six putative new hits in Mycobacterium tuberculosis as promising candidates. The TASmania database is available on the following server https://shiny.bioinformatics.unibe.ch/apps/tasmania/.


Assuntos
Antitoxinas , Toxinas Bacterianas , Bases de Dados de Proteínas , Antitoxinas/química , Antitoxinas/genética , Toxinas Bacterianas/química , Toxinas Bacterianas/genética , Análise por Conglomerados , Biologia Computacional/métodos , Cadeias de Markov , Software
6.
FEMS Microbiol Ecol ; 95(4)2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30830210

RESUMO

The Gram-negative bacterium Vibrio parahaemolyticus (Vp) is a major cause of illness associated with the consumption of raw or undercooked seafood, primarily oysters. This species is a natural member of the bacterial community in brackish waters and is bioaccumulated by oysters through filter feeding. Only a subset of strains is thought to be pathogenic. Currently known virulence markers include the gene for the thermostable direct hemolysin (tdh). In this work we analyzed water and oysters for total Vp and strains encoding tdh from 26 oyster-growing areas of the Puget Sound and Pacific coast of Washington state in 2007 and 2008. In addition, possible plankton-associated Vp were assessed from net tow samples. The density of both total and tdh+ Vp in the water column were considerably higher in 2008 than 2007. However, the concentrations of both total and tdh+ Vp in the oyster tissue was similar for both years. A high proportion of Vp strains in the water column was found to be tdh+ in both 2007 and 2008; however, tdh+ strains were detected at much lower levels in oysters. The data show that analysis of Vp density in the oysters is a better risk assessment tool than density in the overlying water column.


Assuntos
Ostreidae/microbiologia , Vibrio parahaemolyticus/isolamento & purificação , Microbiologia da Água , Animais , Toxinas Bacterianas/genética , Proteínas Hemolisinas/genética , Plâncton/microbiologia , Medição de Risco , Água do Mar/microbiologia , Vibrio parahaemolyticus/genética , Vibrio parahaemolyticus/patogenicidade , Virulência/genética , Washington
7.
BMC Microbiol ; 19(1): 11, 2019 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-30634926

RESUMO

BACKGROUND: Arcobacter faecis and A. lanthieri are two newly classified species of genus Arcobacter. The prevalence and distribution of virulence, antibiotic resistance and toxin (VAT) genes in these species are required to assess their potential pathogenic health impacts to humans and animals. This study (i) developed species- and gene-specific primer pairs for the detection of six virulence, two antibiotic resistance, and three toxin genes in two target species; (ii) optimized eight single-tube multiplex and three monoplex PCR protocols using the newly developed species- and gene-specific primers; and (iii) conducted specificity and sensitivity evaluations as well as validation of eleven mono- and multiplex PCR assays by testing A. faecis (n= 29) and A. lanthieri (n= 10) strains isolated from various fecal and agricultural water sources to determine the prevalence and distribution of VAT genes and assess the degree of pathogenicity within the two species. RESULTS: Detection of all ten and eleven target VAT genes, and expression of cytolethal distending toxin (cdtA, cdtB and cdtC) genes in A. faecis and A. lanthieri reference strains with high frequency in field isolates suggest that they are potentially pathogenic strains. These findings indicate that these two species can pose a health risk to humans and animals. CONCLUSIONS: The study results show that the developed mono- and multiplex PCR (mPCR) assays are simple, rapid, reliable and sensitive for the simultaneous assessment of the potential pathogenicity and antibiotic resistance profiling of tet(O) and tet(W) genes in these two newly discovered species. Also, these assays can be useful in diagnostic and analytical laboratories to determine the pathotypes and assessment of the virulence and toxin factors associated to human and animal infections.


Assuntos
Arcobacter , Toxinas Bacterianas/genética , Técnicas de Tipagem Bacteriana/métodos , Resistência Microbiana a Medicamentos/genética , Infecções por Bactérias Gram-Negativas/microbiologia , Reação em Cadeia da Polimerase , Virulência/genética , Animais , Arcobacter/efeitos dos fármacos , Arcobacter/genética , Arcobacter/patogenicidade , Técnicas de Tipagem Bacteriana/normas , Genes Bacterianos/genética , Infecções por Bactérias Gram-Negativas/diagnóstico , Humanos , Reação em Cadeia da Polimerase Multiplex/normas , Reação em Cadeia da Polimerase/normas , Sensibilidade e Especificidade
8.
Toxins (Basel) ; 10(11)2018 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-30441856

RESUMO

Staphylococcus aureus is a nosocomial pathogen that can cause chronic to persistent infections. Among different mediators of pathogenesis, toxin-antitoxin (TA) systems are emerging as the most prominent. These systems are frequently studied in Escherichia coli and Mycobacterial species but rarely explored in S. aureus. In the present study, we thoroughly analyzed the S. aureus genome and screened all possible TA systems using the Rasta bacteria and toxin-antitoxin database. We further searched E. coli and Mycobacterial TA homologs and selected 67 TA loci as putative TA systems in S. aureus. The host inhibition of growth (HigBA) TA family was predominantly detected in S. aureus. In addition, we detected seven pathogenicity islands in the S. aureus genome that are enriched with virulence genes and contain 26 out of 67 TA systems. We ectopically expressed multiple TA genes in E. coli and S. aureus that exhibited bacteriostatic and bactericidal effects on cell growth. The type I Fst toxin created holes in the cell wall while the TxpA toxin reduced cell size and induced cell wall septation. Besides, we identified a new TA system whose antitoxin functions as a transcriptional autoregulator while the toxin functions as an inhibitor of autoregulation. Altogether, this study provides a plethora of new as well as previously known TA systems that will revitalize the research on S. aureus TA systems.


Assuntos
Toxinas Bacterianas/genética , Toxinas Bacterianas/imunologia , Staphylococcus aureus/genética , Staphylococcus aureus/imunologia , Sistemas Toxina-Antitoxina/genética , Biologia Computacional , Escherichia coli/genética , Escherichia coli/imunologia , Mycobacterium/genética , Mycobacterium/imunologia
10.
Genome Biol ; 19(1): 94, 2018 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-30021593

RESUMO

BACKGROUND: Fitness costs imposed on bacteria by antibiotic resistance mechanisms are believed to hamper their dissemination. The scale of these costs is highly variable. Some, including resistance of Staphylococcus aureus to the clinically important antibiotic mupirocin, have been reported as being cost-free, which suggests that there are few barriers preventing their global spread. However, this is not supported by surveillance data in healthy communities, which indicate that this resistance mechanism is relatively unsuccessful. RESULTS: Epistasis analysis on two collections of MRSA provides an explanation for this discord, where the mupirocin resistance-conferring mutation of the ileS gene appears to affect the levels of toxins produced by S. aureus when combined with specific polymorphisms at other loci. Proteomic analysis demonstrates that the activity of the secretory apparatus of the PSM family of toxins is affected by mupirocin resistance. As an energetically costly activity, this reduction in toxicity masks the fitness costs associated with this resistance mutation, a cost that becomes apparent when toxin production becomes necessary. This hidden fitness cost provides a likely explanation for why this mupirocin-resistance mechanism is not more prevalent, given the widespread use of this antibiotic. CONCLUSIONS: With dwindling pools of antibiotics available for use, information on the fitness consequences of the acquisition of resistance may need to be considered when designing antibiotic prescribing policies. However, this study suggests there are levels of depth that we do not understand, and that holistic, surveillance and functional genomics approaches are required to gain this crucial information.


Assuntos
Antibacterianos/farmacologia , Epistasia Genética , Aptidão Genética/efeitos dos fármacos , Genoma Bacteriano , Isoleucina-tRNA Ligase/genética , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Mupirocina/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/biossíntese , Toxinas Bacterianas/genética , Farmacorresistência Bacteriana , Evolução Molecular , Loci Gênicos , Isoleucina-tRNA Ligase/metabolismo , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/metabolismo , Testes de Sensibilidade Microbiana , Mutação , Proteômica/métodos
11.
Sci Rep ; 7: 40660, 2017 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-28106142

RESUMO

Bicomponent pore-forming leukocidins are a family of potent toxins secreted by Staphylococcus aureus, which target white blood cells preferentially and consist of an S- and an F-component. The S-component recognizes a receptor on the host cell, enabling high-affinity binding to the cell surface, after which the toxins form a pore that penetrates the cell lipid bilayer. Until now, six different leukocidins have been described, some of which are host and cell specific. Here, we identify and characterise a novel S. aureus leukocidin; LukPQ. LukPQ is encoded on a 45 kb prophage (ΦSaeq1) found in six different clonal lineages, almost exclusively in strains cultured from equids. We show that LukPQ is a potent and specific killer of equine neutrophils and identify equine-CXCRA and CXCR2 as its target receptors. Although the S-component (LukP) is highly similar to the S-component of LukED, the species specificity of LukPQ and LukED differs. By forming non-canonical toxin pairs, we identify that the F-component contributes to the observed host tropism of LukPQ, thereby challenging the current paradigm that leukocidin specificity is driven solely by the S-component.


Assuntos
Leucocidinas/genética , Leucocidinas/metabolismo , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo , Animais , Toxinas Bacterianas/genética , Toxinas Bacterianas/metabolismo , Bovinos , Sobrevivência Celular , Ordem dos Genes , Doenças dos Cavalos/microbiologia , Cavalos , Especificidade de Hospedeiro , Humanos , Neutrófilos/metabolismo , Filogenia , Ligação Proteica , Receptores de Interleucina-8B/metabolismo , Infecções Estafilocócicas/microbiologia
12.
Environ Pollut ; 222: 94-100, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28082132

RESUMO

The common soil arthropod Folsomia candida can survive well when fed only maize pollen and thus may be exposed to insecticidal proteins by ingesting insect-resistant genetically engineered maize pollen containing Bacillus thuringiensis (Bt) proteins when being released into the soil. Laboratory experiments were conducted to assess the potential effects of Cry1Ab/Cry2Aj-producing transgenic Bt maize (Shuangkang 12-5) pollen on F. candida fitness. Survival, development, and the reproduction were not significantly reduced when F. candida fed on Bt maize pollen rather than on non-Bt maize pollen, but these parameters were significantly reduced when F. candida fed on non-Bt maize pollen containing the protease inhibitor E-64 at 75 µg/g pollen. The intrinsic rate of increase (rm) was not significantly reduced when F. candida fed on Bt maize pollen but was significantly reduced when F. candida fed on non-Bt maize pollen containing E-64. The activities of antioxidant-related enzymes in F. candida were not significantly affected when F. candida fed on Bt maize pollen but were significantly increased when F. candida fed on non-Bt pollen containing E-64. The results demonstrate that consumption of Bt maize pollen containing Cry1Ab/Cry2Aj has no lethal or sublethal effects on F. candida.


Assuntos
Artrópodes/efeitos dos fármacos , Proteínas de Bactérias/metabolismo , Endotoxinas/metabolismo , Proteínas Hemolisinas/metabolismo , Inseticidas/metabolismo , Controle Biológico de Vetores , Pólen/química , Zea mays , Ração Animal/efeitos adversos , Ração Animal/análise , Animais , Artrópodes/enzimologia , Artrópodes/metabolismo , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/genética , Proteínas de Bactérias/toxicidade , Toxinas Bacterianas/genética , Toxinas Bacterianas/metabolismo , Toxinas Bacterianas/farmacologia , China , Endotoxinas/genética , Endotoxinas/toxicidade , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/toxicidade , Inseticidas/toxicidade , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Precursores de Proteínas/genética , Precursores de Proteínas/metabolismo , Solo/química
13.
Curr Genet ; 63(1): 69-74, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27276988

RESUMO

Toxin-antitoxin (TA) loci were first described as killing systems for plasmid maintenance. The surprisingly abundant presence of TA loci in bacterial chromosomes has stimulated an extensive research in the recent decade aimed to understand the biological importance of these potentially deadly systems. Accumulating evidence suggests that the evolutionary success of genomic TA systems could be explained by their ability to increase bacterial fitness under stress conditions. While TA systems remain quiescent under favorable growth conditions, the toxins can be activated in response to stress resulting in growth suppression and development of stress-tolerant dormant state. Yet, several studies suggest that the TA-mediated stress protection is costly and traded off against decreased fitness under normal growth conditions. Here, we give an overview of the fitness benefits of the chromosomal TA systems, and discuss the costs of TA-mediated stress protection.


Assuntos
Antitoxinas/genética , Antitoxinas/metabolismo , Toxinas Bacterianas/genética , Toxinas Bacterianas/metabolismo , Adaptação Biológica , Fenômenos Fisiológicos Bacterianos , Meio Ambiente , Regulação Bacteriana da Expressão Gênica , Aptidão Genética , Viabilidade Microbiana , Estresse Fisiológico
14.
Appl Microbiol Biotechnol ; 101(7): 2747-2766, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28013405

RESUMO

D2C7-(scdsFv)-PE38KDEL (D2C7-IT) is a novel recombinant Pseudomonas exotoxin A-based immunotoxin (IT), targeting both wild-type epidermal growth factor receptor (EGFRwt) and mutant EGFR variant III (EGFRvIII) proteins overexpressed in glioblastomas. Initial pre-clinical testing demonstrated the anti-tumor efficacy of D2C7-IT against orthotopic glioblastoma xenograft models expressing EGFRwt, EGFRvIII, or both EGFRwt and EGFRvIII. A good laboratory practice (GLP) manufacturing process was developed to produce sufficient material for a phase I/II clinical trial. D2C7-IT was expressed under the control of the T7 promoter in Escherichia coli BLR (λ DE3). D2C7-IT was produced by a 10-L batch fermentation process and was then purified from inclusion bodies using anion exchange, size exclusion, and an endotoxin removal process that achieved a yield of over 300 mg of purified protein. The final vialed batch of D2C7-IT for clinical testing was at a concentration of 0.12 ± 0.1 mg/mL, the pH was at 7.4 ± 0.4, and endotoxin levels were below the detection limit of 10 EU/mL (1.26 EU/mL). The stability of the vialed D2C7-IT has been monitored over a period of 42 months through protein concentration, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), isoelectric focusing, size exclusion chromatography, cytotoxicity, sterility, and pH measurements. The vialed D2C7-IT is currently being tested in a phase I/II clinical trial by intratumoral convection-enhanced delivery for 72 h in patients with recurrent glioblastoma (NCT02303678, D2C7 for Adult Patients with Recurrent Malignant Glioma; clinicaltrials.gov ).


Assuntos
Imunotoxinas/metabolismo , ADP Ribose Transferases/genética , Adulto , Toxinas Bacterianas/genética , Linhagem Celular Tumoral , Ensaios Clínicos Fase I como Assunto , Ensaios Clínicos Fase II como Assunto , Estabilidade de Medicamentos , Eletroforese em Gel de Poliacrilamida , Receptores ErbB/genética , Receptores ErbB/metabolismo , Escherichia coli/genética , Exotoxinas/genética , Fermentação , Glioblastoma/tratamento farmacológico , Humanos , Imunotoxinas/química , Imunotoxinas/genética , Imunotoxinas/uso terapêutico , Controle de Qualidade , Fatores de Virulência/genética , Exotoxina A de Pseudomonas aeruginosa
15.
World J Microbiol Biotechnol ; 33(1): 17, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27900629

RESUMO

α-Toxin, a pore-forming toxin secreted by most Staphylococcus aureus, plays critical role in the pathogenesis associated with various infectious diseases. The USA300 which is a major international epidemic methicilin-resisrant S. aureus has spread rapidly to multiple countries and become an emerging public health concern. In this study, the in vitro efficacy of Dracorhodin Perochlorate (DP) against USA300 virulence was evaluated. Using susceptibility testing, immunoblots, rabbit blood haemolytic assay and real-time RT-PCR, we observed that the α-toxin production was decreased when USA300 was co-cultured with different sub-inhibitory concentration of DP. Further, the protective effect of DP against USA300-mediated injury of human alveolar epithelial cells (A549) and MH-S cells was evaluated by cytotoxicity assays, and the result revealed that DP, at final concentration of 16 µg/ml, is a potent antagonist for USA300-mediated cell damage. Importantly, those beneficial effects might partially correlate with hla and RNAIII suppression by DP, leading to the inhibition of α-toxin production in culture supernatant. Overall, these results suggest that DP could attenuate the virulence of USA300 by decreasing α-toxin production without inhibiting bacterial growth, and this compound may represent an ideal candidate for the development of anti-virulence agent combating S. aureus infection.


Assuntos
Antibacterianos/farmacologia , Toxinas Bacterianas/genética , Toxinas Bacterianas/metabolismo , Benzopiranos/farmacologia , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/metabolismo , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Animais , Linhagem Celular , Sobrevivência Celular , Regulação para Baixo , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Humanos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Coelhos , Virulência/efeitos dos fármacos
16.
Biosens Bioelectron ; 81: 317-323, 2016 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-26985584

RESUMO

This study describes a simple and sensitive approach for visual and point-of-care detection of P. aeruginosa and its toxin genes based on multiple loop-mediated isothermal amplification (mLAMP) and lateral flow nucleic acid biosensor (LFNAB). Differentiation of the internal standard gene ecfX and toxin genes (ExoS and ExoU) in P. aeruginosa was determined using FITC-, hex-and digoxin-modified primers in the mLAMP process. In the presence of biotin-and FITC- (hex-, digoxin-) modified primers and Bst DNA polymerase large fragments, the mLAMP produced numerous biotin- and FITC- (hex-, digoxin-) attached duplex DNA products. The products were detected by LFNAB through dual immunoreactions (anti-biotin antibodies on the gold nanoparticle (Au-NP) and biotin on the duplex, anti-FITC (hex, digoxin) antibodies on the LFNAB test line and FITC (hex, digoxin) on the duplex). The accumulation of Au-NPs produced a characteristic red band, enabling visual detection of P. aeruginosa and its toxin genes without instrumentation. After systematic optimization of LFNAB preparation and detecting conditions, the current approach was capable of detecting concentrations as low as 20 CFU/mL P. aeruginosa or its toxin genes within 50min without complicated instrument, which is more sensitive than PCR. Therefore, this approach provides a simple, pollution free, sensitive, and low-cost point-of-care test for the detection of P. aeruginosa and its toxin genes.


Assuntos
ADP Ribose Transferases/genética , Proteínas de Bactérias/genética , Toxinas Bacterianas/genética , Técnicas Biossensoriais/instrumentação , Sistemas Automatizados de Assistência Junto ao Leito , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/genética , Toxinas Biológicas/genética , Técnicas Biossensoriais/economia , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Água Potável/microbiologia , Humanos , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico/economia , Técnicas de Amplificação de Ácido Nucleico/instrumentação , Sistemas Automatizados de Assistência Junto ao Leito/economia , Pseudomonas aeruginosa/isolamento & purificação , Reprodutibilidade dos Testes , Rios/microbiologia , Microbiologia da Água
17.
Hum Exp Toxicol ; 35(8): 818-32, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26437792

RESUMO

Probiotics are live microorganisms ingested for the purpose of conferring a health benefit on the host. Development of new probiotics includes the need for safety evaluations that should consider factors such as pathogenicity, infectivity, virulence factors, toxicity, and metabolic activity. Clostridium butyricum MIYAIRI 588(®) (CBM 588(®)), an anaerobic spore-forming bacterium, has been developed as a probiotic for use by humans and food animals. Safety studies of this probiotic strain have been conducted and include assessment of antimicrobial sensitivity, documentation of the lack of Clostridium toxin genes, and evaluation of CBM 588(®) on reproductive and developmental toxicity in a rodent model. With the exception of aminoglycosides, to which anaerobes are intrinsically resistant, CBM 588(®) showed sensitivity to all antibiotic classes important in human and animal therapeutics. In addition, analysis of the CBM 588(®) genome established the absence of genes for encoding for α, ß, or ε toxins and botulin neurotoxins types A, B, E, or F. There were no deleterious reproductive and developmental effects observed in mice associated with the administration of CBM 588(®) These data provide further support for the safety of CBM 588(®) for use as a probiotic in animals and humans.


Assuntos
Anormalidades Induzidas por Medicamentos , Antibacterianos/farmacologia , Toxinas Bacterianas/genética , Clostridium butyricum/genética , Probióticos/toxicidade , Reprodução/efeitos dos fármacos , Anormalidades Induzidas por Medicamentos/etiologia , Animais , Toxinas Botulínicas/genética , Clostridium butyricum/efeitos dos fármacos , Farmacorresistência Bacteriana , Enterotoxinas/genética , Feminino , Masculino , Camundongos , Camundongos Endogâmicos ICR , Testes de Sensibilidade Microbiana , Neurotoxinas/genética , Gravidez , Probióticos/farmacologia , Probióticos/normas
18.
Microb Pathog ; 86: 1-9, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26055540

RESUMO

The oral cavity is regarded as a relevant site for Staphylococcus aureus colonization. However, characterization of virulence mechanisms of oral S. aureus remains to be uncovered. In this study, twenty one S. aureus strains isolated from the oral cavity of Tunisian patients were screened for adherence, invasion and cytotoxicity against HeLa cells. In addition, the presence of adhesins (icaA, icaD, can, fnbA and fnbB) and α-hemolysin (hla) genes in each strain was achieved by polymerase chain reaction (PCR). Our finding revealed that oral S. aureus strains were able to adhere and invade epithelial cells, with variable degrees (P < 0.05). Moreover they exhibited either low (23.8%) or moderate (76.2%) cytotoxic effects. In addition 76.2% of strains were icaA and icaD positive and 90.5% harbor both the fnbA and the fnbB gene. While the cna gene was detected in 12 strains (57.2%). Furthermore, the hla gene encoding the α-toxin was found in 52.4% of the isolates. All these virulence factors give to S. aureus the right qualities to become a redoubtable pathogen associated to oral infections.


Assuntos
Aderência Bacteriana , Endocitose , Staphylococcus aureus/fisiologia , Staphylococcus aureus/patogenicidade , Adesinas Bacterianas/genética , Toxinas Bacterianas/genética , Sobrevivência Celular , Células HeLa , Proteínas Hemolisinas/genética , Humanos , Reação em Cadeia da Polimerase , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/citologia , Staphylococcus aureus/isolamento & purificação , Tunísia , Virulência
19.
Clin Microbiol Infect ; 20(11): O904-10, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24674056

RESUMO

In June 2012, Israeli guidelines for laboratories were published defining the recommended methods for diagnosis of Clostridium difficile infection (CDI). We conducted this survey to examine the effects of the new recommendations on the proportions of rejected and positive samples by the different methods. A survey was mailed to the directors of all general hospital (GH) and health maintenance organization (HMO) clinical microbiology laboratories. The report was divided into two periods, before and after implementation of the guidelines. Surveys were completed by 13/28 GH laboratories and 5/6 HMO laboratories. All 18 of these laboratories used C. difficile toxin (CDT) enzyme immunoassay alone during the first period of the survey. In the second period, nine laboratories (Group A) used CDT-PCR: two of them used this method exclusively while the other seven used it to resolve most (>90%) of the discrepant results (glutamate dehydrogenase antigen (GDH) +/CDT-]. The other nine laboratories (Group B) used combined GDH/CDT assay, using CDT PCR in only a minority (<20%) of GDH+/CDT- cases. The overall proportion of rejected samples increased from 9.5% in the first period to 13.9% in the second (p<0.001). Between the first and second periods the proportion of positive samples increased from 9.0% to 11.6% in group A laboratories (p<0.001), but decreased from 12.9% to 9.7% in group B laboratories (p<0.001). Implementation of the guidelines has resulted in a significant increase in the proportion of rejected samples and in the proportion testing positive, suggesting more appropriate test utilization and improved sensitivity in the laboratory diagnosis of CDI.


Assuntos
Técnicas Bacteriológicas/métodos , Clostridioides difficile/isolamento & purificação , Infecções por Clostridium/diagnóstico , Infecções por Clostridium/epidemiologia , Diarreia/diagnóstico , Diarreia/epidemiologia , Antígenos de Bactérias/análise , Toxinas Bacterianas/análise , Toxinas Bacterianas/genética , Infecções por Clostridium/microbiologia , Coleta de Dados , Diarreia/microbiologia , Monitoramento Epidemiológico , Política de Saúde , Hospitais Gerais , Humanos , Israel , Técnicas de Diagnóstico Molecular/métodos , Guias de Prática Clínica como Assunto
20.
Lett Appl Microbiol ; 58(5): 401-7, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24286182

RESUMO

UNLABELLED: A specific latex agglutination test (LAT) based on anti-PA (protective antigen) antibodies having detection limit of 5 × 10(4) formalin treated Bacillus anthracis cells or 110 ng of PA was optimized in this study. The optimized LAT could detect anthrax toxin in whole blood as well as in serum from the animal models of anthrax infection. The protocol is a simple and promising method for the specific detection of bacteria causing anthrax under routine laboratory, as well as in field, conditions without any special equipments or expertise. SIGNIFICANCE AND IMPACT OF THE STUDY: The article presents the first report of a latex agglutination test for the specific identification of the cultures of bacteria causing anthrax. As the test is targeting one of anthrax toxic protein (PA), this can also be used to determine virulence of suspected organisms. At the same time, the same LAT can be used directly on whole blood or sera samples under field conditions for the specific diagnosis of anthrax.


Assuntos
Antraz/diagnóstico , Antraz/microbiologia , Antígenos de Bactérias/genética , Bacillus anthracis/isolamento & purificação , Toxinas Bacterianas/genética , Testes de Fixação do Látex/métodos , Animais , Antraz/imunologia , Bacillus anthracis/genética , Bacillus cereus , Cobaias , Testes de Fixação do Látex/economia , Limite de Detecção , Coelhos , Proteínas Recombinantes/genética
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