Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 15.424
Filtrar
1.
Sci Rep ; 12(1): 13992, 2022 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-35978046

RESUMO

Proteus mirabilis (P. mirabilis) is a frequent cause of catheter-associated urinary tract infections. This study aims to investigate the anti-infective effect of Alhagi maurorum extract (AME), the traditional medicinal plant in the middle east, on the biofilm-forming P. mirabilis isolates. Hydroalcoholic extract and oil of A. maurorum were characterized by HPLC and GC-MS. The antiproliferative, anti-biofilm, and bactericidal activity of AME at various concentrations were assessed by turbidity, crystal violet binding, and agar well diffusion assays, respectively. The AME's effect on adhesion and quorum sensing (QS) were investigated by in vitro adhesion assay on cell culture and agar overlay assay using Janthinobacterium lividum (ATCC 12472) as a biosensor strain. In addition, the expression level of selected genes involved in QS and biofilm regulation were determined by quantitative Real-Time PCR. Furthermore, the bladder phantom model was created to evaluate the assays and investigate the catheter's calcium deposition. The most effective chemical compounds found in AME were tamarixetin, quercetin, and trans-anethole. Although AME did not inhibit swarming motility, it reduced biofilm production and exerted a concentration-dependent anti-adhesive and anti-QS activity against P. mirabilis. AME also downregulated the expression level of selected genes involved in biofilm formation and QS. This study showed that AME as a natural compound reduced biofilm formation of P. mirabilis by targeting virulence factor genes, quorum sensing, and other strategies that include preventing the adhesion of P. mirabilis to the cells. The results suggest that A. maurorum extract might have the potential to be considered for preventing UTIs caused by P. mirabilis.


Assuntos
Biofilmes , Fabaceae , Extratos Vegetais , Plantas Medicinais , Proteus mirabilis , Percepção de Quorum , Ágar , Antibacterianos/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Cateteres/efeitos adversos , Cateteres/microbiologia , Fabaceae/química , Humanos , Fitoterapia , Extratos Vegetais/farmacologia , Plantas Medicinais/química , Proteus mirabilis/efeitos dos fármacos , Proteus mirabilis/genética , Proteus mirabilis/patogenicidade , Proteus mirabilis/fisiologia , Percepção de Quorum/efeitos dos fármacos , Percepção de Quorum/genética , Infecções Urinárias/microbiologia , Virulência/efeitos dos fármacos , Virulência/genética
2.
Annu Rev Microbiol ; 76: 503-532, 2022 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-35671532

RESUMO

Biofilms are a widely observed growth mode in which microbial communities are spatially structured and embedded in a polymeric extracellular matrix. Here, we focus on the model bacterium Vibrio cholerae and summarize the current understanding of biofilm formation, including initial attachment, matrix components, community dynamics, social interactions, molecular regulation, and dispersal. The regulatory network that orchestrates the decision to form and disperse from biofilms coordinates various environmental inputs. These cues are integrated by several transcription factors, regulatory RNAs, and second-messenger molecules, including bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP). Through complex mechanisms, V. cholerae weighs the energetic cost of forming biofilms against the benefits of protection and social interaction that biofilms provide.


Assuntos
Biofilmes , Vibrio cholerae , Proteínas de Bactérias/metabolismo , Biofilmes/crescimento & desenvolvimento , GMP Cíclico/metabolismo , Regulação Bacteriana da Expressão Gênica , Fatores de Transcrição/metabolismo , Vibrio cholerae/genética , Vibrio cholerae/fisiologia
3.
Microbiologyopen ; 11(1): e1261, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35212481

RESUMO

Candida auris is an emerging fungal superbug of worldwide interest. It is associated with high mortality rates and exhibits increased resistance to antifungals. Ultraviolet subtype C (UVC) light can be used to disinfect surfaces to mitigate its spread. The objectives of this study were (1) To investigate UVC disinfection performances and wavelength sensitivity of C. auris. (2) To evaluate the UVC dose required for the prevention of biofilm formation on stainless-steel, plastic (polystyrene), and poly-cotton fabric surfaces. C. auris was grown following standard procedures. The study utilized six different UVC LED arrays with wavelengths between 252 and 280 nm. Arrays were set at similar intensities, to obtain doses of 5-40 mJ cm-2 and similar irradiation time. Disinfection performance for each array was determined using log reduction value (LRV) and percentage reduction by comparing the controls against the irradiated treatments. Evaluation of the ability of 267 nm UVC LEDs to prevent C. auris biofilm formation was investigated using stainless-steel, plastic coupons, and poly-cotton fabric. Peak sensitivity to UVC disinfection was between 267 and 270 nm. With 20 mJ cm-2 , the study obtained ≥LRV3. On stainless-steel coupons, 30 mJ cm-2 was sufficient to prevent biofilm formation, while on plastic, this required 10 mJ cm-2 . A dose of 60 mJ cm-2 reduced biofilms on poly-cotton fabric significantly (R2 = 0.9750, p = 0.0002). The study may allow for the design and implementation of disinfection systems.


Assuntos
Biofilmes/crescimento & desenvolvimento , /efeitos da radiação , Raios Ultravioleta , Biofilmes/efeitos da radiação , /fisiologia , Resistência a Múltiplos Medicamentos/efeitos da radiação , Raios Ultravioleta/classificação
4.
Int J Mol Sci ; 23(3)2022 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-35162964

RESUMO

The branched aerobic respiratory chain in Bacillus cereus comprises three terminal oxidases: cytochromes aa3, caa3, and bd. Cytochrome caa3 requires heme A for activity, which is produced from heme O by heme A synthase (CtaA). In this study, we deleted the ctaA gene in B. cereus AH187 strain, this deletion resulted in loss of cytochrome caa3 activity. Proteomics data indicated that B. cereus grown in glucose-containing medium compensates for the loss of cytochrome caa3 activity by remodeling its respiratory metabolism. This remodeling involves up-regulation of cytochrome aa3 and several proteins involved in redox stress response-to circumvent sub-optimal respiratory metabolism. CtaA deletion changed the surface-composition of B. cereus, affecting its motility, autoaggregation phenotype, and the kinetics of biofilm formation. Strikingly, proteome remodeling made the ctaA mutant more resistant to cold and exogenous oxidative stresses compared to its parent strain. Consequently, we hypothesized that ctaA inactivation could improve B. cereus fitness in a nutrient-limited environment.


Assuntos
Bacillus cereus/crescimento & desenvolvimento , Proteínas de Bactérias/genética , Grupo dos Citocromos b/genética , Grupo dos Citocromos c/metabolismo , Citocromos a3/metabolismo , Citocromos a/metabolismo , Deleção de Genes , Proteínas de Membrana/genética , Bacillus cereus/genética , Bacillus cereus/metabolismo , Proteínas de Bactérias/metabolismo , Biofilmes/crescimento & desenvolvimento , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Heme/análogos & derivados , Heme/metabolismo , Estresse Oxidativo , Fenótipo , Proteômica , Transdução de Sinais
5.
Microbiol Spectr ; 10(1): e0176821, 2022 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-35196792

RESUMO

Carbapenem resistance of Acinetobacter baumannii poses challenges to public health. Biofilm contributes to the persistence of A. baumannii cells. This study was designed to investigate the genetic relationships among carbapenem resistance, polymyxin resistance, multidrug resistance, biofilm formation, and surface-associated motility and evaluate the antibiofilm effect of polymyxin in combination with other antibiotics. A total of 103 clinical A. baumannii strains were used to determine antibiotic susceptibility, biofilm formation capacity, and motility. Enterobacterial repetitive intergenic consensus (ERIC)-PCR fingerprinting was used to determine the genetic variation among strains. The distribution of 17 genes related to the resistance-nodulation-cell division (RND)-type efflux, autoinducer-receptor (AbaI/AbaR) quorum sensing, oxacillinases (OXA)-23, and insertion sequence of ISAba1 element was investigated. The representative strains were chosen to evaluate the gene transcription and the antibiofilm activity by polymyxin B (PB) in combination with merapenem, levofloxacin, and ceftazidime, respectively. ERIC-PCR-dependent fingerprints were found to be associated with carbapenem resistance and multidrug resistance. The presence of blaOXA-23 was found to correlate with genes involved in ISAba1 insertion, AbaI/AbaR quorum sensing, and AdeABC efflux. Carbapenem resistance was observed to be negatively correlated with biofilm formation and positively correlated with motility. PB in combination with ceftazidime displayed a synergistic antibiofilm effect against robust biofilm formed by an A. baumannii strain with deficiency in AbaI/AbaR quorum sensing. Our results not only clarify the genetic correlation among carbapenem resistance, biofilm formation, and pathogenicity in a certain level but also provide a theoretical basis for clinical applications of polymyxin-based combination of antibiotics in antibiofilm therapy. IMPORTANCE Deeper explorations of molecular correlation among antibiotic resistance, biofilm formation, and pathogenicity could provide novel insights that would facilitate the development of therapeutics and prevention against A. baumannii biofilm-related infections. The major finding that polymyxin B in combination with ceftazidime displayed a synergistic antibiofilm effect against robust biofilm formed by an A. baumannii strain with genetic deficiency in AbaI/AbaR quorum sensing further provides a theoretical basis for clinical applications of antibiotics in combination with quorum quenching in antibiofilm therapy.


Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/genética , Proteínas de Bactérias/genética , Biofilmes/efeitos dos fármacos , Ceftazidima/uso terapêutico , Polimixina B/uso terapêutico , Percepção de Quorum/genética , Infecções por Acinetobacter/tratamento farmacológico , Acinetobacter baumannii/crescimento & desenvolvimento , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Biofilmes/crescimento & desenvolvimento , Ceftazidima/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/genética , Quimioterapia Combinada/métodos , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase , Polimixina B/farmacologia , Percepção de Quorum/efeitos dos fármacos , beta-Lactamases/genética
6.
Viruses ; 14(2)2022 01 27.
Artigo em Inglês | MEDLINE | ID: mdl-35215857

RESUMO

Vibrio parahaemolyticus causes aquatic vibriosis. Its biofilm protects it from antibiotics; therefore, a new different method is needed to control V. parahaemolyticus for food safety. Phage therapy represents an alternative strategy to control biofilms. In this study, the lytic Vibrio phage vB_VpaP_FE11 (FE11) was isolated from the sewers of Guangzhou Huangsha Aquatic Market. Electron microscopy analysis revealed that FE11 has a typical podovirus morphology. Its optimal stability temperature and pH range were found to be 20-50 °C and 5-10 °C, respectively. It was completely inactivated following ultraviolet irradiation for 20 min. Its latent period is 10 min and burst size is 37 plaque forming units/cell. Its double-stranded DNA genome is 43,397 bp long, with a G + C content of 49.24% and 50 predicted protein-coding genes. As a lytic phage, FE11 not only prevented the formation of biofilms but also could destroy the formed biofilms effectively. Overall, phage vB_VpaP_FE11 is a potential biological control agent against V. parahaemolyticus and the biofilm it produces.


Assuntos
Bacteriófagos/fisiologia , Biofilmes/crescimento & desenvolvimento , Podoviridae/fisiologia , Vibrio parahaemolyticus/fisiologia , Vibrio parahaemolyticus/virologia , Bacteriólise , Bacteriófagos/classificação , Bacteriófagos/genética , Bacteriófagos/isolamento & purificação , Agentes de Controle Biológico , Genoma Viral , Especificidade de Hospedeiro , Terapia por Fagos , Filogenia , Podoviridae/classificação , Podoviridae/genética , Podoviridae/isolamento & purificação , Esgotos/virologia
7.
Microbiol Spectr ; 10(1): e0205621, 2022 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-35107361

RESUMO

The Gram-positive anaerobic bacterium Cutibacterium acnes is a major inhabitant of human skin and has been implicated in acne vulgaris formation and in the formation of multispecies biofilms with other skin-inhabiting organisms like Staphylococcus aureus and Candida albicans. Indoles are widespread in nature (even in human skin) and function as important signaling molecules in diverse prokaryotes and eukaryotes. In the present study, we investigated the antibacterial and antibiofilm activities of 20 indoles against C. acnes. Of the indoles tested, indole-3-carbinol at 0.1 mM significantly inhibited biofilm formation by C. acnes without affecting planktonic cell growth, and the anticancer drug 3,3'-diindolylmethane (DIM) at 0.1 mM (32 µg/mL) also significantly inhibited planktonic cell growth and biofilm formation by C. acnes, whereas the other indoles and indole itself were less effective. Also, DIM at 0.1 mM successfully inhibited multispecies biofilm formation by C. acnes, S. aureus, and C. albicans. Transcriptional analyses showed that DIM inhibited the expressions of several biofilm-related genes in C. acnes, and at 0.05 mM, DIM inhibited hyphal formation and cell aggregation by C. albicans. These results suggest that DIM and other indoles inhibit biofilm formation by C. acnes and have potential use for treating C. acnes associated diseases. IMPORTANCE Since indoles are widespread in nature (even in human skin), we hypothesized that indole and its derivatives might control biofilm formation of acne-causing bacteria (Cutibacterium acnes and Staphylococcus aureus) and fungal Candida albicans. The present study reports for the first time the antibiofilm and antimicrobial activities of several indoles on C. acnes. Of the indoles tested, two anticancer agents, indole-3-carbinol and 3,3'-diindolylmethane found in cruciferous vegetables, significantly inhibited biofilm formation by C. acnes. Furthermore, the most active 3,3'-diindolylmethane successfully inhibited multispecies biofilm formation by C. acnes, S. aureus, and C. albicans. Transcriptional analyses showed that 3,3'-diindolylmethane inhibited the expressions of several biofilm-related genes including lipase, hyaluronate lyase, and virulence-related genes in C. acnes, and 3,3'-diindolylmethane inhibited hyphal formation and cell aggregation by C. albicans. Our findings show that 3,3'-diindolylmethane offers a potential means of controlling acne vulgaris and multispecies biofilm-associated infections due to its antibiofilm and antibiotic properties.


Assuntos
Acne Vulgar/microbiologia , Antineoplásicos/farmacologia , Bactérias/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Candida albicans/efeitos dos fármacos , Indóis/farmacologia , Antibacterianos/farmacologia , Bactérias/crescimento & desenvolvimento , Candida albicans/crescimento & desenvolvimento , Humanos , Testes de Sensibilidade Microbiana , Filogenia , Propionibacteriaceae/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Virulência
8.
BMC Microbiol ; 22(1): 52, 2022 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-35148684

RESUMO

Citrus greening, also known as Huanglongbing (HLB), is a devastating citrus plant disease caused predominantly by Liberibacter asiaticus. While nearly all Liberibacter species remain uncultured, here we used the culturable L. crescens BT-1 as a model to examine physiological changes in response to the variable osmotic conditions and nutrient availability encountered within the citrus host. Similarly, physiological responses to changes in growth temperature and dimethyl sulfoxide concentrations were also examined, due to their use in many of the currently employed therapies to control the spread of HLB. Sublethal heat stress was found to induce the expression of genes related to tryptophan biosynthesis, while repressing the expression of ribosomal proteins. Osmotic stress induces expression of transcriptional regulators involved in expression of extracellular structures, while repressing the biosynthesis of fatty acids and aromatic amino acids. The effects of osmotic stress were further evaluated by quantifying biofilm formation of L. crescens in presence of increasing sucrose concentrations at different stages of biofilm formation, where sucrose-induced osmotic stress delayed initial cell attachment while enhancing long-term biofilm viability. Our findings revealed that exposure to osmotic stress is a significant contributing factor to the long term survival of L. crescens and, possibly, to the pathogenicity of other Liberibacter species.


Assuntos
Biofilmes/crescimento & desenvolvimento , Citrus/microbiologia , Viabilidade Microbiana , Pressão Osmótica , Doenças das Plantas/microbiologia , Liberibacter/patogenicidade , Liberibacter/fisiologia , Fatores de Tempo
9.
Nat Commun ; 13(1): 827, 2022 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-35149676

RESUMO

Nanozyme is a collection of nanomaterials with enzyme-like activity but higher environmental tolerance and long-term stability than their natural counterparts. Improving the catalytic activity and expanding the category of nanozymes are prerequisites to complement or even supersede enzymes. However, the development of hydrolytic nanozymes is still challenged by diverse hydrolytic substrates and following complicated mechanisms. Here, two strategies are informed by data to screen and predict catalytic active sites of MOF (metal-organic framework) based hydrolytic nanozymes: (1) to increase the intrinsic activity by finely tuned Lewis acidity of the metal clusters; (2) to improve the density of active sites by shortening the length of ligands. Finally, as-obtained Ce-FMA-MOF-based hydrolytic nanozyme is capable of cleaving phosphate bonds, amide bonds, glycosidic bonds, and even their mixture, biofilms. This work provides a rational methodology to design hydrolytic nanozyme, enriches the diversity of nanozymes, and potentially sheds light on future evolution of enzyme engineering.


Assuntos
Enzimas/química , Enzimas/metabolismo , Nanoestruturas/química , Biofilmes/crescimento & desenvolvimento , Catálise , Domínio Catalítico , Glicosídeo Hidrolases/química , Hidrólise , Íons , Ligantes , Estruturas Metalorgânicas/química , Metais , Monoéster Fosfórico Hidrolases/química
10.
Int J Mol Sci ; 23(3)2022 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-35163081

RESUMO

Extensive biofilm formation on materials used in restorative dentistry is a common reason for their failure and the development of oral diseases like peri-implantitis or secondary caries. Therefore, novel materials and strategies that result in reduced biofouling capacities are urgently sought. Previous research suggests that surface structures in the range of bacterial cell sizes seem to be a promising approach to modulate bacterial adhesion and biofilm formation. Here we investigated bioadhesion within the oral cavity on a low surface energy material (perfluorpolyether) with different texture types (line-, hole-, pillar-like), feature sizes in a range from 0.7-4.5 µm and graded distances (0.7-130.5 µm). As a model system, the materials were fixed on splints and exposed to the oral cavity. We analyzed the enzymatic activity of amylase and lysozyme, pellicle formation, and bacterial colonization after 8 h intraoral exposure. In opposite to in vitro experiments, these in situ experiments revealed no clear signs of altered bacterial surface colonization regarding structure dimensions and texture types compared to unstructured substrates or natural enamel. In part, there seemed to be a decreasing trend of adherent cells with increasing periodicities and structure sizes, but this pattern was weak and irregular. Pellicle formation took place on all substrates in an unaltered manner. However, pellicle formation was most pronounced within recessed areas thereby partially masking the three-dimensional character of the surfaces. As the natural pellicle layer is obviously the most dominant prerequisite for bacterial adhesion, colonization in the oral environment cannot be easily controlled by structural means.


Assuntos
Bactérias/metabolismo , Aderência Bacteriana , Biofilmes/crescimento & desenvolvimento , Película Dentária/fisiologia , Modelos Biológicos , Boca/fisiologia , Bactérias/crescimento & desenvolvimento , Película Dentária/química , Película Dentária/microbiologia , Humanos , Boca/química , Boca/microbiologia , Propriedades de Superfície
11.
Int J Mol Sci ; 23(3)2022 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-35163165

RESUMO

Recently, the drawbacks arising from the overuse of antibiotics have drawn growing public attention. Among them, drug-resistance (DR) and even multidrug-resistance (MDR) pose significant challenges in clinical practice. As a representative of a DR or MDR pathogen, Staphylococcus aureus can cause diversity of infections related to different organs, and can survive or adapt to the diverse hostile environments by switching into other phenotypes, including biofilm and small colony variants (SCVs), with altered physiologic or metabolic characteristics. In this review, we briefly describe the development of the DR/MDR as well as the classical mechanisms (accumulation of the resistant genes). Moreover, we use multidimensional scaling analysis to evaluate the MDR relevant hotspots in the recent published reports. Furthermore, we mainly focus on the possible non-classical resistance mechanisms triggered by the two important alternative phenotypes of the S. aureus, biofilm and SCVs, which are fundamentally caused by the different global regulation of the S. aureus population, such as the main quorum-sensing (QS) and agr system and its coordinated regulated factors, such as the SarA family proteins and the alternative sigma factor σB (SigB). Both the biofilm and the SCVs are able to escape from the host immune response, and resist the therapeutic effects of antibiotics through the physical or the biological barriers, and become less sensitive to some antibiotics by the dormant state with the limited metabolisms.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Biofilmes/crescimento & desenvolvimento , Farmacorresistência Bacteriana/genética , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/genética , Animais , Proteínas de Bactérias/genética , Biofilmes/efeitos dos fármacos , Regulação Bacteriana da Expressão Gênica , Humanos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/patogenicidade
12.
PLoS One ; 17(2): e0263059, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35108308

RESUMO

We used the method of measuring potential difference between two Ag|AgCl electrodes immersed directly into electrolyte solution with lower concentration and at different distances from membrane. The bacterial cellulose membrane was placed in horizontal plane in the membrane system with configurations with higher NaCl concentration and density under (A) and over the membrane (B). In both configurations at the initial moment the voltage between electrodes amounted to zero. After turning off mechanical stirring of solutions, in configuration A we observed the monotonic increase and next stabilization of voltage while in configuration B after short time dependent on the initial quotient of NaCl concentrations on the membrane we observed appearance of pulsations of measured voltage and gradual decrease of mean voltage over time. Smooth changes of voltage are connected with diffusional reconstruction of Concentration Boundary Layers (CBLs) while fast increase and subsequent pulsations of voltage are connected with the appearance of hydrodynamic instabilities (gravitational convection) near membrane imposed on diffusive reconstruction of thin layer. The time needed for the appearance of hydrodynamic instabilities in CBL depended nonlinearly on the initial ratio of electrolyte concentrations on the membrane.


Assuntos
Bactérias/metabolismo , Biofilmes/crescimento & desenvolvimento , Celulose/química , Eletrodos , Membranas Artificiais , Compostos de Prata/química , Prata/química , Difusão , Eletrólitos , Hidrodinâmica , Osmose , Permeabilidade , Polímeros
13.
Molecules ; 27(3)2022 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-35163933

RESUMO

The use of nitric oxide (NO) is emerging as a promising, novel approach for the treatment of antibiotic resistant bacteria and biofilm infections. Depending on the concentration, NO can induce biofilm dispersal, increase bacteria susceptibility to antibiotic treatment, and induce cell damage or cell death via the formation of reactive oxygen or reactive nitrogen species. The use of NO is, however, limited by its reactivity, which can affect NO delivery to its target site and result in off-target effects. To overcome these issues, and enable spatial or temporal control over NO release, various strategies for the design of NO-releasing materials, including the incorporation of photo-activable, charge-switchable, or bacteria-targeting groups, have been developed. Other strategies have focused on increased NO storage and delivery by encapsulation or conjugation of NO donors within a single polymeric framework. This review compiles recent developments in NO drugs and NO-releasing materials designed for applications in antimicrobial or anti-biofilm treatment and discusses limitations and variability in biological responses in response to the use of NO for bacterial eradiation.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Doadores de Óxido Nítrico/farmacologia , Bactérias/metabolismo , Biofilmes/efeitos dos fármacos
14.
Proc Natl Acad Sci U S A ; 119(7)2022 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-35145026

RESUMO

Bacteroides thetaiotaomicron is a gut symbiont that inhabits the mucus layer and adheres to and metabolizes food particles, contributing to gut physiology and maturation. Although adhesion and biofilm formation could be key features for B. thetaiotaomicron stress resistance and gut colonization, little is known about the determinants of B. thetaiotaomicron biofilm formation. We previously showed that the B. thetaiotaomicron reference strain VPI-5482 is a poor in vitro biofilm former. Here, we demonstrated that bile, a gut-relevant environmental cue, triggers the formation of biofilm in many B. thetaiotaomicron isolates and common gut Bacteroidales species. We determined that bile-dependent biofilm formation involves the production of the DNase BT3563 or its homologs, degrading extracellular DNA (eDNA) in several B. thetaiotaomicron strains. Our study therefore shows that, although biofilm matrix eDNA provides a biofilm-promoting scaffold in many studied Firmicutes and Proteobacteria, BT3563-mediated eDNA degradation is required to form B. thetaiotaomicron biofilm in the presence of bile.


Assuntos
Proteínas de Bactérias/metabolismo , Bacteroides thetaiotaomicron/enzimologia , Bile/metabolismo , Biofilmes/crescimento & desenvolvimento , Desoxirribonucleases/metabolismo , Regulação Bacteriana da Expressão Gênica/fisiologia , Proteínas de Bactérias/genética , Bacteroides thetaiotaomicron/genética , Bacteroides thetaiotaomicron/fisiologia , DNA Bacteriano/genética , DNA Bacteriano/metabolismo , Desoxirribonucleases/genética , Regulação Enzimológica da Expressão Gênica/fisiologia
15.
BMC Microbiol ; 22(1): 29, 2022 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-35042478

RESUMO

BACKGROUND: Asymptomatic bacteriuria (ASB) frequently occurs among all ages and may develop into urinary tract infections (UTIs). Hypervirulent Klebsiella pneumoniae (hvKP) has become a new threat to human health. In our study, we aimed to investigate the epidemiological characteristics of hvKP in population with ASB. RESULTS: A total of 61 K. pneumoniae isolates were collected from 7530 urine samples between October and December 2020. The strains were sensitive to most of the antimicrobial agents tested, but a polymyxin resistant strain was found (MIC>16 µg/mL). Three serotypes were detected, including K1 (16.4%, 10/61), K5 (1.6%, 1/61) and K57 (3.2%, 2/61). Four strains (KPNY9, KPNY31, KPNY40, and KPNY42) carried a combination of two or more hypervirulent markers (peg-344, iroB, iucA, prmpA, and prmpA2), and their survival rates after Galleria mellonella infection were lower than those of the other strains (40.0 vs. 70.0%), suggesting that they were hvKP. These hvKP strains with lower biofilm forming ability than classical K. pneumoniae (0.2625 ± 0.0579 vs. 0.6686 ± 0.0661, P = 0.033) were identified as belonging to K2-ST65, K2-ST86, K57-ST592, and K2-ST5559 (a new ST type). KPNY31 (ST5559) shared a close genetic relationship with KPNY42 (ST86) and other ST86 isolates, which have been detected in both nosocomial and community-acquired infections. CONCLUSIONS: The hvKP with relatively weak biofilm formation was detected in a population with ASB, which was more likely to cause bacteremia and serious consequences. A novel sequence type (ST5559) hvKP derived from ST86 was found. Therefore, hvKP should be monitored in the population with ASB.


Assuntos
Infecções Assintomáticas/epidemiologia , Bacteriúria/epidemiologia , Farmacorresistência Bacteriana Múltipla , Infecções por Klebsiella/epidemiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/patogenicidade , Adulto , Animais , Biofilmes/crescimento & desenvolvimento , Feminino , Humanos , Infecções por Klebsiella/etnologia , Infecções por Klebsiella/microbiologia , Infecções por Klebsiella/urina , Klebsiella pneumoniae/genética , Larva/microbiologia , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Mariposas/microbiologia , Filogenia , Fatores de Virulência/genética
16.
ACS Appl Mater Interfaces ; 14(5): 6307-6319, 2022 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-35099179

RESUMO

Biofilms are central to some of the most urgent global challenges across diverse fields of application, from medicine to industries to the environment, and exert considerable economic and social impact. A fundamental assumption in anti-biofilms has been that the coating on a substrate surface is solid. The invention of slippery liquid-infused porous surfaces─a continuously wet lubricating coating retained on a solid surface by capillary forces─has led to this being challenged. However, in situations where flow occurs, shear stress may deplete the lubricant and affect the anti-biofilm performance. Here, we report on the use of slippery omniphobic covalently attached liquid (SOCAL) surfaces, which provide a surface coating with short (ca. 4 nm) non-cross-linked polydimethylsiloxane (PDMS) chains retaining liquid-surface properties, as an antibiofilm strategy stable under shear stress from flow. This surface reduced biofilm formation of the key biofilm-forming pathogens Staphylococcus epidermidis and Pseudomonas aeruginosa by three-four orders of magnitude compared to the widely used medical implant material PDMS after 7 days under static and dynamic culture conditions. Throughout the entire dynamic culture period of P. aeruginosa, SOCAL significantly outperformed a typical antibiofilm slippery surface [i.e., swollen PDMS in silicone oil (S-PDMS)]. We have revealed that significant oil loss occurred after 2-7 day flow for S-PDMS, which correlated to increased contact angle hysteresis (CAH), indicating a degradation of the slippery surface properties, and biofilm formation, while SOCAL has stable CAH and sustainable antibiofilm performance after 7 day flow. The significance of this correlation is to provide a useful easy-to-measure physical parameter as an indicator for long-term antibiofilm performance. This biofilm-resistant liquid-like solid surface offers a new antibiofilm strategy for applications in medical devices and other areas where biofilm development is problematic.


Assuntos
Biofilmes/crescimento & desenvolvimento , Dimetilpolisiloxanos/química , Óleos de Silicone/química , Biofilmes/efeitos dos fármacos , Biomassa , Dimetilpolisiloxanos/farmacologia , Interações Hidrofóbicas e Hidrofílicas , Porosidade , Pseudomonas aeruginosa/fisiologia , Staphylococcus epidermidis/fisiologia , Propriedades de Superfície , Molhabilidade
17.
Mol Med ; 28(1): 10, 2022 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-35093033

RESUMO

BACKGROUND: Biofilm is a community of bacteria embedded in an extracellular matrix, which can colonize different human cells and tissues and subvert the host immune reactions by preventing immune detection and polarizing the immune reactions towards an anti-inflammatory state, promoting the persistence of biofilm-embedded bacteria in the host. MAIN BODY OF THE MANUSCRIPT: It is now well established that the function of immune cells is ultimately mediated by cellular metabolism. The immune cells are stimulated to regulate their immune functions upon sensing danger signals. Recent studies have determined that immune cells often display distinct metabolic alterations that impair their immune responses when triggered. Such metabolic reprogramming and its physiological implications are well established in cancer situations. In bacterial infections, immuno-metabolic evaluations have primarily focused on macrophages and neutrophils in the planktonic growth mode. CONCLUSION: Based on differences in inflammatory reactions of macrophages and neutrophils in planktonic- versus biofilm-associated bacterial infections, studies must also consider the metabolic functions of immune cells against biofilm infections. The profound characterization of the metabolic and immune cell reactions could offer exciting novel targets for antibiofilm therapy.


Assuntos
Biofilmes , Suscetibilidade a Doenças/imunologia , Suscetibilidade a Doenças/metabolismo , Interações Hospedeiro-Patógeno , Infecções/etiologia , Infecções/metabolismo , Neoplasias/complicações , Animais , Biofilmes/crescimento & desenvolvimento , Biomarcadores , Gerenciamento Clínico , Metabolismo Energético , Humanos , Sistema Imunitário/imunologia , Sistema Imunitário/metabolismo , Infecções/diagnóstico , Infecções/terapia , Neoplasias/etiologia , Neoplasias/metabolismo , Neoplasias/terapia , Especificidade de Órgãos
18.
Sci Rep ; 12(1): 1251, 2022 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-35075262

RESUMO

Staphylococcus aureus is an opportunistic, pathogenic bacteria that causes significant morbidity and mortality. As antibiotic resistance by S. aureus continues to be a serious concern, developing novel drug therapies to combat these infections is vital. Quorum sensing inhibitors (QSI) dampen S. aureus virulence and facilitate clearance by the host immune system by blocking quorum sensing signaling that promotes upregulation of virulence genes controlled by the accessory gene regulator (agr) operon. While QSIs have shown therapeutic promise in mouse models of S. aureus skin infection, their further development has been hampered by the suggestion that agr inhibition promotes biofilm formation. In these studies, we investigated the relationship between agr function and biofilm growth across various S. aureus strains and experimental conditions, including in a mouse model of implant-associated infection. We found that agr deletion was associated with the presence of increased biofilm only under narrow in vitro conditions and, crucially, was not associated with enhanced biofilm development or enhanced morbidity in vivo.


Assuntos
Proteínas de Bactérias/fisiologia , Biofilmes/crescimento & desenvolvimento , Staphylococcus aureus/fisiologia , Transativadores/fisiologia , Animais , Técnicas de Cultura , Feminino , Camundongos Endogâmicos BALB C , Percepção de Quorum
19.
APMIS ; 130(3): 181-192, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34978741

RESUMO

Mycobacterium tuberculosis (M. tuberculosis) Rv1002c encodes the protein O-mannosyltransferase (PMT), which catalyzes the transfer of mannose to serine or threonine residues of proteins. We explored the function of PMT in vitro and in vivo. Rv1002c protein was heterogeneously overexpressed in nonpathogenic Mycobacterium smegmatis (named as MS_Rv1002c). A series of trials including mass spectrometry, transmission electron microscope, biofilm formation and antibiotics susceptibility were performed to explore the function of PMT on bacterial survival in vitro. Mouse experiments were carried out to evaluate the virulence of PMT in vivo. PMT decreased the cell envelope permeability and promoted microbial biofilm formation. PMT enhanced the mycobacterial survival in vivo and inhibited the release of pro-inflammatory cytokines in serum. The function might be associated with an increased abundance of some mannoproteins in culture filtrate (CF). PMT is likely to be involved in mycobacterial survival both in vivo and in vitro due to increasing the mannoproteins abundance in CF.


Assuntos
Biofilmes/crescimento & desenvolvimento , Permeabilidade da Membrana Celular/fisiologia , Manosiltransferases/metabolismo , Mycobacterium tuberculosis/patogenicidade , Animais , Proteínas de Bactérias/metabolismo , Citocinas/metabolismo , Inflamação/metabolismo , Inflamação/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Mycobacterium smegmatis/metabolismo , Mycobacterium tuberculosis/metabolismo , Permeabilidade , Virulência/fisiologia
20.
PLoS One ; 17(1): e0261893, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35073323

RESUMO

Combating the spread of antimicrobial resistance (AMR) among bacteria requires a new class of antimicrobials, which desirably have a narrow spectrum because of their low propensity for the spread of AMR. Antimicrobial peptides (AMPs), which target the bacterial cell membrane, are promising seeds for novel antimicrobials because the cell membrane is essential for all cells. Previously, we reported the antimicrobial and haemolytic effects of a natural AMP, magainin 2 (Mag2), isolated from the skin of Xenopus laevis (the African clawed frog), four types of synthesised Mag2 derivatives, and three types of rationally designed AMPs on gram-positive and gram-negative bacteria. To identify novel antimicrobial seeds, we evaluated the effect of AMPs on Mycoplasma pneumoniae, which also exhibits AMR. We also evaluated the antimicrobial effects of an AMP, NK2A, which has been reported to have antimicrobial effects on Mycoplasma bovis, in addition to Mag2 and previously synthesised seven AMPs, on four strains of M. pneumoniae using colorimetric, biofilm, and killing assays. We found that three synthesised AMPs, namely 17base-Ac6c, 17base-Hybrid, and Block, had anti-M. pneumoniae (anti-Mp) effect at 8-30 µM, whereas others, including NK2A, did not have any such effect. For the further analysis, the membrane disruption activities of AMPs were measured by propidium iodide (PI) uptake assays, which suggested the direct interaction of AMPs to the cell membrane basically following the colorimetric, biofilm, and killing assay results. PI uptake assay, however, also showed the NK2A strong interaction to cell membrane, indicating unknown anti-Mp determinant factors related to the peptide sequences. Finally, we conclude that anti-Mp effect was not simply determined by the membrane disruption activities of AMPs, but also that the sequence of AMPs were important for killing of M. pneumoniae. These findings would be helpful for the development of AMPs for M. pneumoniae.


Assuntos
Antibacterianos , Biofilmes/efeitos dos fármacos , Desenho de Fármacos , Magaininas , Mycoplasma pneumoniae/fisiologia , Proteínas de Xenopus , Animais , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/farmacologia , Biofilmes/crescimento & desenvolvimento , Magaininas/síntese química , Magaininas/química , Magaininas/farmacologia , Mycoplasma bovis/fisiologia , Proteínas de Xenopus/síntese química , Proteínas de Xenopus/química , Proteínas de Xenopus/farmacologia , Xenopus laevis
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...