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1.
Food Microbiol ; 111: 104208, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36681392

RESUMO

Induced electric field (IEF), as an alternative non-conventional processing technique, is utilized to sterilize liquid foods. In this study, the survival and sublethal injury of S. aureus under IEF were investigated in 0.85% normal saline, and the inactivation mechanism of IEF was expounded. The plate count results showed that the sublethal injury rates remained above 90% after IEF treatment for more than 8.4 s, and 7.1 log CFU/mL of S. aureus was completely inactivated after 14 s IEF treatment. Scanning electron microscopy and transmission electron microscope images showed that IEF caused the destruction of cell membrane and internal substructure, and the damage to intracellular substructure was more severe. Altered membrane integrity or permeability was demonstrated through flow cytometry and confocal laser scanning microscope analysis, and the different damage to cells was quantified by propidium iodide & 5-carboxy fluorescein diacetate single and double staining. In addition, IEF treatment also decreased the membrane potential and esterase activity of S. aureus cells. Putative inactivation mechanism of IEF against S. aureus is a complex process, and its apoptosis is the result of the combination of several factors, which provide a basis for understanding the inactivation mechanism of IEF.


Assuntos
Anti-Infecciosos , Staphylococcus aureus , Staphylococcus aureus/fisiologia , Membrana Celular , Microscopia Eletrônica de Varredura
2.
Chem Commun (Camb) ; 59(5): 587-590, 2023 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-36524690

RESUMO

Staphylococcus aureus uses small peptides to assess its population densisty (i.e., quorum sensing) and regulate virulence at high cell number. Here, we report the design and synthesis of peptidomimetics based on these native signals that strongly block this communication pathway in all four specificity groups of S. aureus.


Assuntos
Peptidomiméticos , Infecções Estafilocócicas , Humanos , Staphylococcus aureus/fisiologia , Peptidomiméticos/farmacologia , Peptidomiméticos/metabolismo , Percepção de Quorum , Proteínas de Bactérias/metabolismo , Peptídeos/metabolismo
3.
Biomater Adv ; 145: 213238, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36527962

RESUMO

The eradication of bacteria embedded in biofilms is among the most challenging obstacles in the management of chronic wounds. These biofilms are found in most chronic wounds; moreover, the biofilm-embedded bacteria are considerably less susceptible to conventional antimicrobial treatment than the planktonic bacteria. Antimicrobial peptides and their mimics are considered attractive candidates in the pursuit of novel therapeutic options for the treatment of chronic wounds and general bacterial eradication. However, some limitations linked to these membrane-active antimicrobials are making their clinical use challenging. Novel innovative delivery systems addressing these limitations represent a smart solution. We hypothesized that incorporation of a novel synthetic mimic of an antimicrobial peptide in liposomes could improve its anti-biofilm effect as well as the anti-inflammatory activity. The small synthetic mimic of an antimicrobial peptide, 7e-SMAMP, was incorporated into liposomes (~280 nm) tailored for skin wounds and evaluated for its potential activity against both biofilm formation and eradication of pre-formed biofilms. The 7e-SMAMP-liposomes significantly lowered inflammatory response in murine macrophages (~30 % reduction) without affecting the viability of macrophages or keratinocytes. Importantly, the 7e-SMAMP-liposomes completely eradicated biofilms produced by Staphylococcus aureus and Escherichia coli above concentrations of 6.25 µg/mL, whereas in Pseudomonas aeruginosa the eradication reached 75 % at the same concentration. Incorporation of 7e-SMAMP in liposomes improved both the inhibition of biofilm formation as well as biofilm eradication in vitro, as compared to non-formulated antimicrobial, therefore confirming its potential as a novel therapeutic option for bacteria-infected chronic wounds.


Assuntos
Anti-Infecciosos , Peptídeos Antimicrobianos , Animais , Camundongos , Lipossomos , Anti-Infecciosos/farmacologia , Staphylococcus aureus/fisiologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Biofilmes
4.
J Dairy Sci ; 106(2): 1370-1382, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36526461

RESUMO

Intramammary infections (IMI) are common in nonlactating dairy cattle and are expected to impair mammary growth and development and reduce future milk production. The objective of this study was to histologically evaluate how IMI alter tissue structure in growing and developing heifer mammary glands. A total of 18 nonpregnant, nonlactating heifers between 11 and 14 mo of age were used in the present study. Heifers received daily supraphysiological injections of estradiol and progesterone for 14 d to stimulate rapid mammary growth and development. One-quarter of each heifer was subsequently infused with Staphylococcus aureus (CHALL) while a second quarter served as an uninfected control (UNINF). Heifers were randomly selected and euthanized either the last day of hormonal injections to observe IMI effects on mammary gland growth (GRO), or 13 d post-injections, to observe IMI effects on mammary development (DEV). Mammary tissues were collected from the center and edge parenchymal regions of each mammary gland for morphometric tissue area evaluation. For GRO tissues, CHALL quarters had less epithelial tissue area and marginally more intralobular stroma tissue area than UNINF quarters. Tissue areas occupied by luminal space, extralobular stroma, adipose, and lobular tissue were similar. For DEV tissues, area occupied by epithelium, luminal space, intralobular stroma, and extralobular stroma did not differ between quarter treatments, but UNINF quarters had more adipose tissue area and marginally less lobular area than CHALL quarters. Results indicate that IMI in growing and developing mammary glands reduces mammary epithelial growth and alters mammary gland development by impairing epithelial branching into the mammary fat pad. Taken together, these tissue changes before calving may have adverse effects on milk production. Therefore, an important focus should be placed on improving udder health in replacement heifers through management strategies that mitigate the deleterious effects of IMI and promote the positive development of the mammary gland.


Assuntos
Doenças dos Bovinos , Mastite Bovina , Infecções Estafilocócicas , Bovinos , Feminino , Animais , Staphylococcus aureus/fisiologia , Leite , Mastite Bovina/patologia , Infecções Estafilocócicas/veterinária , Progesterona/farmacologia , Glândulas Mamárias Animais , Doenças dos Bovinos/patologia
5.
Sci Rep ; 12(1): 21846, 2022 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-36528648

RESUMO

Chronic wounds cannot heal due to impairment of regeneration, mainly caused by the persistent infection of multispecies biofilms. Still, the effects of biofilm wound infection and its interaction with the host are not fully described. We aimed to study functional biofilms in physiological conditions in vitro, and their potential effects in health and regeneration in vivo. Therefore, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis were seeded in collagen-based scaffolds for dermal regeneration. After 24 h, scaffolds had bacterial loads depending on the initial inoculum, containing viable biofilms with antibiotic tolerance. Afterwards, scaffolds were implanted onto full skin wounds in mice, together with daily supervision and antibiotic treatment. Although all mice survived their health was affected, displaying fever and weight loss. After ten days, histomorphology of scaffolds showed high heterogeneity in samples and within groups. Wounds were strongly, mildly, or not infected according to colony forming units, and P. aeruginosa had higher identification frequency. Biofilm infection induced leucocyte infiltration and elevated interferon-γ and interleukin-10 in scaffolds, increase of size and weight of spleen and high systemic pro-calcitonin concentrations. This functional and implantable 3D biofilm model allows to study host response during infection, providing a useful tool for infected wounds therapy development.


Assuntos
Infecções por Pseudomonas , Infecção dos Ferimentos , Camundongos , Animais , Infecções por Pseudomonas/microbiologia , Infecção dos Ferimentos/microbiologia , Biofilmes , Pseudomonas aeruginosa , Staphylococcus aureus/fisiologia , Antibacterianos/farmacologia
6.
PLoS One ; 17(12): e0276795, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36520793

RESUMO

The prevalence and virulence of pathogens such as methicillin-resistant Staphylococcus (S.) aureus (MRSA), which can cause recurrent skin infections, are of significant clinical concern. Prolonged antibiotic exposure to treat or decolonize S. aureus contributes to development of antibiotic resistance, as well as depletion of the microbiome, and its numerous beneficial functions. We hypothesized an engineered skin probiotic with the ability to selectively deliver antimicrobials only in the presence of the target organism could provide local bioremediation of pathogen colonization. We constructed a biosensing S. epidermidis capable of detecting the presence of S. aureus quorum sensing autoinducer peptide and producing lysostaphin in response. Here, we demonstrate in vitro activity of this biosensor and present and discuss challenges to deployment of this and other engineered topical skin probiotics.


Assuntos
Staphylococcus aureus Resistente à Meticilina , Probióticos , Infecções Estafilocócicas , Humanos , Staphylococcus aureus/fisiologia , Antibacterianos/uso terapêutico , Virulência , Probióticos/uso terapêutico , Infecções Estafilocócicas/tratamento farmacológico , Testes de Sensibilidade Microbiana
7.
Front Cell Infect Microbiol ; 12: 1038253, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36325465

RESUMO

The nasogastric enteral feeding tubes (NEFTs) used to feed preterm infants are commonly colonized by bacteria with the ability to form complex biofilms in their inner surfaces. Among them, staphylococci (mainly Staphylococcus epidermidis and Staphylococcus aureus) and some species belonging to the Family Enterobacteriaceae are of special concern since they can cause nosocomial infections in this population. NETF-associated biofilms can also include lactic acid bacteria (LAB), with the ability to compete with pathogenic species for nutrients and space. Ecological interactions among the main colonizers of these devices have not been explored yet; however, such approach could guide future strategies involving the pre-coating of the inner surfaces of NEFTs with well adapted LAB strains in order to reduce the rates of nosocomial infections in neonatal intensive care units (NICUs). In this context, this work implied the formation of dual-species biofilms involving one LAB strain (either Ligilactobacillus salivarius 20SNG2 or Limosilactobacillus reuteri 7SNG3) and one nosocomial strain (either Klebsiella pneumoniae 9SNG3, Serratia marcescens 10SNG3, Staphylococcus aureus 45SNG3 or Staphylococcus epidermidis 46SNG3). The six strains used in this study had been isolated from the inner surface of NEFTs. Changes in adhesion ability of the pathogens were characterized using a culturomic approach. Species interactions and structural changes of the resulting biofilms were analyzed using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). No aggregation was observed in dual-species biofilms between any of the two LAB strains and either K. pneumoniae 9SNG3 or S. marcescens 10SNG3. In addition, biofilm thickness and volume were reduced, suggesting that both LAB strains can control the capacity to form biofilms of these enterobacteria. In contrast, a positive ecological relationship was observed in the combination L. reuteri 7SNG3-S. aureus 45SNG3. This relationship was accompanied by a stimulation of S. aureus matrix production when compared with its respective monospecies biofilm. The knowledge provided by this study may guide the selection of potentially probiotic strains that share the same niche with nosocomial pathogens, enabling the establishment of a healthier microbial community inside NEFTs.


Assuntos
Infecção Hospitalar , Lactobacillales , Infecções Estafilocócicas , Humanos , Recém-Nascido , Staphylococcus aureus/fisiologia , Recém-Nascido Prematuro , Biofilmes , Staphylococcus epidermidis , Enterobacteriaceae , Serratia marcescens , Klebsiella pneumoniae
8.
ACS Nano ; 16(10): 16549-16562, 2022 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-36218160

RESUMO

Pathogenic bacterial infection and poor native tissue integration are two major issues encountered by biomaterial implants and devices, which are extremely hard to overcome within a single surface, especially for those without involvement of antibiotics. Herein, a self-adaptive surface that can transform from non-antibiotic antibacterial actions to promotion of cell proliferation is developed by in situ assembly of bacteriostatic 3,3'-diaminodipropylamine (DADP)-doped zeolitic imidazolate framework-8 (ZIF-8) on bio-inspired nanopillars. Initially, the nanocomposite surface shows impressive antibacterial effects, even under severe bacterial infection, due to the combination of mechano-bactericidal activity from a nanopillar structure and bacteriostatic activity contributed by pH-responsive release of DADP. After the complete degradation of the ZIF-8 layer, the refurbished nanopillars not only can still physically rupture bacterial membrane but also facilitate mammalian cell proliferation, due to the obvious difference in cell size. More strikingly, the nanocomposite surface totally avoids the usage of antibiotics, eradicating the potential risk of antimicrobial resistance, and the surface exhibited excellent histocompatibility and lower inflammatory response properties as revealed by in vivo tests. This type of self-adaptive surface may provide a promising alternative for addressing the intractable implant-associated requirements, where antibiotic-free antibacterial activity and native tissue integration are both highly needed.


Assuntos
Nanocompostos , Zeolitas , Animais , Antibacterianos/farmacologia , Antibacterianos/química , Staphylococcus aureus/fisiologia , Materiais Biocompatíveis/farmacologia , Bactérias , Proliferação de Células , Mamíferos
9.
Molecules ; 27(20)2022 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-36296467

RESUMO

(1) Background: Staphylococcus aureus (S. aureus) is one of the most frequent causes of biofilm-associated infections. With the emergence of antibiotic-resistant, especially methicillin-resistant S. aureus (MRSA), there is an urgent need to discover novel inhibitory compounds against this clinically important pathogen. In this study, we evaluated the antimicrobial and anti-biofilm activity of 11 compounds, including phenyl propenes and phenolic aldehydes, eugenol, ferulic acid, sinapic acid, salicylaldehyde, vanillin, cinnamoyl acid, and aldehydes, against drug-resistant S. aureus isolates. (2) Methods: Thirty-two clinical S. aureus isolates were obtained from Alkhidmat Diagnostic Center and Blood Bank, Karachi, Pakistan, and screened for biofilm-forming potential, and susceptibility/resistance against ciprofloxacin, chloramphenicol, ampicillin, amikacin, cephalothin, clindamycin, streptomycin, and gentamicin using the Kirby-Bauer disk diffusion method. Subsequently, 5 representative clinical isolates were selected and used to test the antimicrobial and anti-biofilm potential of 11 compounds using both qualitative and quantitative assays, followed by qPCR analysis to examine the differences in the expression levels of biofilm-forming genes (ica-A, fnb-B, clf-A and cna) in treated (with natural compounds and their derivatives) and untreated isolates. (3) Results: All isolates were found to be multi-drug resistant and dominant biofilm formers. The individual Minimum Inhibitory Concentration (MIC) of natural compounds and their analogues ranged from 0.75-160 mg/mL. Furthermore, the compounds, Salicylaldehyde (SALI), Vanillin (VAN), α-methyl-trans-cinnamaldehyde (A-MT), and trans-4-nitrocinnamic acid (T4N) exhibited significant (15-92%) biofilm inhibition/reduction percentage capacity at the concentration of 1-10 mg/mL. Gene expression analysis showed that salicylaldehyde, α-methyl-trans-cinnamaldehyde, and α-bromo-trans-cinnamaldehyde resulted in a significant (p < 0.05) downregulation of the expression of ica-A, clf-A, and fnb-A genes compared to the untreated resistant isolate. (4) Conclusions: The natural compounds and their analogues used in this study exhibited significant antimicrobial and anti-biofilm activity against S. aureus. Biofilms persist as the main concern in clinical settings. These compounds may serve as potential candidate drug molecules against biofilm forming S. aureus.


Assuntos
Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Humanos , Staphylococcus aureus/fisiologia , Staphylococcus aureus Resistente à Meticilina/fisiologia , Clindamicina/uso terapêutico , Amicacina , Cefalotina/uso terapêutico , Eugenol/uso terapêutico , Infecções Estafilocócicas/tratamento farmacológico , Aldeídos , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Biofilmes , Testes de Sensibilidade Microbiana , Ciprofloxacina/uso terapêutico , Gentamicinas , Ampicilina/uso terapêutico , Cloranfenicol/uso terapêutico , Estreptomicina
10.
Adv Exp Med Biol ; 1386: 397-424, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36258081

RESUMO

The human pathogens Pseudomonas aeruginosa and Staphylococcus aureus are frequently co-isolated from chronic wounds or cystic fibrosis patient airways. Clinical studies analysing the impact of co-infection on patient clinical outcomes lead to contradictory results. However, laboratory approaches suggest that the two pathogens co-colonize the same infection niches and form a mixed-species biofilm, therefore favouring their resistance to antibiotics and immune response. In parallel, many recent studies have focused on the different interactions between the two bacterial species. It has long been recognized that P. aeruginosa usually outcompetes S. aureus, and the molecular mechanisms involved in this state of bacterial competition are now well understood. However, several recent studies show that interactions between P. aeruginosa and S. aureus can be diverse and evolve over time. Thus, many CF isolates of P. aeruginosa and S. aureus can coexist and develop cooperative behaviours. In this chapter, we will provide an overview of the current knowledge on the mixed populations of P. aeruginosa and S. aureus, from their mechanisms of establishment to their impacts on bacterial physiology and clinical outcomes.


Assuntos
Coinfecção , Infecções Estafilocócicas , Humanos , Staphylococcus aureus/fisiologia , Pseudomonas aeruginosa/fisiologia , Coinfecção/microbiologia , Infecções Estafilocócicas/microbiologia , Biofilmes , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico
11.
Molecules ; 27(18)2022 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-36144496

RESUMO

In this study, we describe the semisynthesis of cost-effective photosensitizers (PSs) derived from chlorophyll a containing different substituents and using previously described methods from the literature. We compared their structures when used in photodynamic inactivation (PDI) against Staphylococcus aureus, Escherichia coli, and Candida albicans under different conditions. The PSs containing carboxylic acids and butyl groups were highly effective against S. aureus and C. albicans following our PDI protocol. Overall, our results indicate that these nature-inspired PSs are a promising alternative to selectively inactivate microorganisms using PDI.


Assuntos
Fotoquimioterapia , Fármacos Fotossensibilizantes , Candida albicans , Ácidos Carboxílicos , Clorofila A , Escherichia coli , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/química , Staphylococcus aureus/fisiologia
12.
Infect Immun ; 90(11): e0023722, 2022 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-36165627

RESUMO

Cystic fibrosis (CF) disease is characterized by lifelong infections with pathogens such as Staphylococcus aureus, leading to eventual respiratory failure. Small colony variants (SCVs) of S. aureus have been linked to worse clinical outcomes for people with CF. Current studies of SCV pathology in vivo are limited, and it remains unclear whether SCVs directly impact patient outcomes or are a result of late-stage CF disease. To investigate this, we generated a stable menadione-auxotrophic SCV strain by serially passaging a CF isolate of S. aureus with tobramycin, an aminoglycoside antibiotic commonly administered for coinfecting Pseudomonas aeruginosa. This SCV was tobramycin resistant and showed increased tolerance to the anti-staphylococcal combination therapy sulfamethoxazole-trimethoprim. To better understand the dynamics of SCV infections in vivo, we infected CF rats with this strain compared with its normal colony variant (NCV). Analysis of bacterial burden at 3 days postinfection indicated that NCVs and SCVs persisted equally well in the lungs, but SCV infections ultimately led to increased weight loss and neutrophilic inflammation. Additionally, cellular and histopathological analyses showed that in CF rats, SCV infections yielded a lower macrophage response. Overall, these findings indicate that SCV infections may directly contribute to lung disease progression in people with CF.


Assuntos
Fibrose Cística , Infecções Estafilocócicas , Ratos , Animais , Staphylococcus aureus/fisiologia , Fibrose Cística/microbiologia , Tobramicina/farmacologia , Tobramicina/uso terapêutico , Infecções Estafilocócicas/microbiologia , Antibacterianos/efeitos adversos , Pulmão/microbiologia , Inflamação
13.
Front Cell Infect Microbiol ; 12: 928220, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36061863

RESUMO

Antimicrobial peptides (AMPs) may be the most promising substitute for antibiotics due to their effective bactericidal activity and multiple antimicrobial modes against pathogenic bacteria. In this study, a new functional gene named Spgillcin was identified in Scylla paramamosain, which encoded 216 amino acids of mature peptide. In vivo, Spgillcin was dominantly expressed in the gills of male and female crabs, offering the highest expression level among all tested organs or tissues. The expression pattern of Spgillcin was significantly altered when challenged by Staphylococcus aureus, indicating a positive immune response. In vitro, a functional truncated peptide Spgillcin177-189 derived from the amino acid sequence of Spgillcin was synthesized and showed a broad-spectrum and potent antibacterial activity against several bacterial strains, including the clinical isolates of multidrug-resistant (MDR) strains, with a range of minimum inhibitory concentrations from 1.5 to 48 µM. Spgillcin177-189 also showed rapid bactericidal kinetics for S. aureus and Pseudomonas aeruginosa but did not display any cytotoxicity to mammalian cells and maintained its antimicrobial activity in different conditions. Mechanistic studies indicated that Spgillcin177-189 was mainly involved in the disruption of cell membrane integrity where the membrane components lipoteichoic acid and lipopolysaccharide could significantly inhibit the antimicrobial activity in a dose-dependent manner. In addition, Spgillcin177-189 could change the membrane permeability and cause the accumulation of intracellular reactive oxygen species. No resistance was generated to Spgillcin177-189 when the clinical isolates of methicillin-resistant S. aureus and MDR P. aeruginosa were treated with Spgillcin177-189 and then subjected to a long term of continuous culturing for 50 days. In addition, Spgillcin177-189 exerted a strong anti-biofilm activity by inhibiting biofilm formation and was also effective at killing extracellular S. aureus in the cultural supernatant of RAW 264.7 cells. Taken together, Spgillcin177-189 has strong potential as a substitute for antibiotics in future aquaculture and medical applications.


Assuntos
Braquiúros , Staphylococcus aureus Resistente à Meticilina , Animais , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/genética , Peptídeos Catiônicos Antimicrobianos/farmacologia , Proteínas de Artrópodes/metabolismo , Bactérias/metabolismo , Braquiúros/genética , Feminino , Masculino , Mamíferos/metabolismo , Testes de Sensibilidade Microbiana , Staphylococcus aureus/fisiologia
14.
J Antimicrob Chemother ; 77(12): 3265-3269, 2022 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-36124848

RESUMO

INTRODUCTION: Levofloxacin and rifampicin are the preferred treatment for prosthetic joint infection (PJI) caused by Staphylococcus aureus, especially when managed with implant retention (DAIR). However, a significant variability of success has been reported, which could be related to intrinsic characteristics of the microorganism. Our aim was to evaluate the variability in the anti-biofilm response to levofloxacin and rifampicin in a clinical collection of S. aureus. MATERIAL AND METHODS: Eleven levofloxacin- and rifampicin-susceptible S. aureus isolates causing PJI managed with DAIR were included. Levofloxacin, rifampicin and levofloxacin + rifampicin were tested in an in vitro static biofilm model in microtitre plates, where 48 h biofilms were challenged with antimicrobials during 24 h. Additionally, two genetically similar strains were tested in the CDC Biofilm Reactor, where 48 h biofilms were treated during 56 h. Antimicrobial activity was assessed by viable biofilm-embedded cells recount, and by crystal violet staining. RESULTS: All antimicrobial regimens showed significant anti-biofilm activity, but a notable scattering in the response was observed across all strains (inter-strain coefficient of variation for levofloxacin, rifampicin and levofloxacin + rifampicin of 22.8%, 35.8% and 34.5%, respectively). This variability was tempered with the combination regimen when tested in the biofilm reactor. No correlation was observed between the minimal biofilm eradicative concentration and the antimicrobial activity. Recurrent S. aureus isolates exhibited higher biofilm-forming ability compared with strains from resolved infections (7.6 log10 cfu/cm2±0.50 versus 9.0 log10 cfu±0.07). CONCLUSIONS: Significant variability may be expected in response to levofloxacin and rifampicin among biofilm-embedded S. aureus. A response in the lower range, together with other factors of bad prognosis, could be responsible of treatment failure.


Assuntos
Artrite Infecciosa , Infecções Estafilocócicas , Humanos , Staphylococcus aureus/fisiologia , Levofloxacino/farmacologia , Levofloxacino/uso terapêutico , Rifampina/farmacologia , Rifampina/uso terapêutico , Infecções Estafilocócicas/tratamento farmacológico , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Biofilmes
15.
Sci Rep ; 12(1): 14963, 2022 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-36056144

RESUMO

Staphylococcus aureus adapts to different environments by sensing and responding to diverse environmental cues. The responses are coordinately regulated by regulatory proteins, and small regulatory RNAs at the transcriptional and translational levels. Here, we characterized teg58, a SarA repressed sRNA, using ChIP-Seq and RNA-Seq analysis of a sarA mutant. Phenotypic and genetic analyses indicated that inactivation of teg58 led to reduced biofilm formation in a process that is independent of SarA, agr, PIA, and PSMs. RNA-Seq analysis of teg58 mutant revealed up-regulation of arginine biosynthesis genes (i.e., argGH) as well as the ability of the mutant to grow in a chemical defined medium (CDM) lacking L-arginine. Exogenous L-arginine or endogenous induction of argGH led to decreased biofilm formation in parental strains. Further analysis in vitro and in vivo demonstrated that the specific interaction between teg58 and the argGH occurred at the post-transcriptional level to repress arginine synthesis. Biochemical and genetic analyses of various arginine catabolic pathway genes demonstrated that the catabolic pathway did not play a significant role in reduced biofilm formation in the teg58 mutant. Overall, results suggest that teg58 is a regulatory sRNA that plays an important role in modulating arginine biosynthesis and biofilm formation in S. aureus.


Assuntos
Pequeno RNA não Traduzido , Infecções Estafilocócicas , Arginina/metabolismo , Proteínas de Bactérias/metabolismo , Biofilmes , Regulação Bacteriana da Expressão Gênica , Humanos , Pequeno RNA não Traduzido/genética , Pequeno RNA não Traduzido/metabolismo , Infecções Estafilocócicas/genética , Staphylococcus aureus/fisiologia , Transativadores/metabolismo
16.
Microb Pathog ; 172: 105789, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36176246

RESUMO

The aim of this study was to evaluate and compare the ability of two S. aureus strains with different adaptation genotypes (low and high) to the bovine mammary gland (MG) to establish an intramammary infection (IMI) and induce an immune response after an experimental challenge in lactating cows. Two isolates (designated 806 and 5011) from bovine IMI with different genotypic profiles, harboring genes involved in adherence and biofilm production, belonging to different capsular polysaccharide (CP) type, accessory gene regulator (agr) group, pulsotype (PT) and sequence type/clonal complex (ST/CC) were selected. Strains 806 and 5011 were associated with low (nonpersistent-NP) and high (persistent-P) adaptation to the MG, respectively. Strain 806 (NP) was characterized as agr group II, cap5 positive and ST350; strain 5011 (P) agr group I, cap8 positive and CC188. Three groups of clinically healthy cows, 4 cows/treatment group, were inoculated by the intramammary route with strain 806 (NP), strain 5011 (P) and pyrogen-free saline solution. All mammary quarters challenged with strain 806 (NP) developed mild clinical mastitis between 1 and 7 d post inoculation (pi). Quarters challenged with strain 5011 (P) developed a persistent IMI; bacteria were recovered from milk from d 7 pi and up to d 56 pi. In quarters inoculated with strain 806 (NP) the inflammatory response induced was greater and earlier than the one induced by strain 5011 (P), since a somatic cell count (SCC) peak was observed at d 2 pi, while in quarters inoculated with strain 5011 (P) no variations in SCC were observed until d 4 pi reaching the maximum values at d 14 pi; indicating a lower and delayed initial inflammatory response. The highest levels of nitric oxide (NO) and lactoferrin (Lf) detected in milk from quarters inoculated with both S. aureus strains coincided with the highest SCC at the same time periods, indicating an association with the magnitude of inflammation. The high levels of IL-1ß induced by strain 806 (NP) were associated with the highest SCC detected (d 2 pi); while quarters inoculated with strain 5011 (P) showed similar IL-1ß levels to those found in control quarters. In quarters inoculated with strain 806 (NP) two peaks of IL-6 levels on d 2 and 14 pi were observed; while in quarters inoculated with strain 5011 (P) IL-6 levels were similar to those found in control quarters. The strain 806 (NP) induced a higher total IgG and IgG1 response; while strain 5011 (P) generated a higher IgG2 response (even against the heterologous strain). The present study demonstrated that S. aureus strains with different genotype and adaptability to bovine MG influence the local host immune response and the course and severity of the infectious process.


Assuntos
Mastite Bovina , Infecções Estafilocócicas , Feminino , Bovinos , Animais , Staphylococcus aureus/fisiologia , Mastite Bovina/microbiologia , Lactação , Óxido Nítrico , Solução Salina , Interleucina-6/genética , Lactoferrina , Infecções Estafilocócicas/microbiologia , Leite/microbiologia , Contagem de Células/veterinária , Genótipo , Imunidade , Imunoglobulina G/genética , Glândulas Mamárias Animais/microbiologia
17.
Elife ; 112022 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-36154945

RESUMO

Long-range material transport is essential to maintain the physiological functions of multicellular organisms such as animals and plants. By contrast, material transport in bacteria is often short-ranged and limited by diffusion. Here, we report a unique form of actively regulated long-range directed material transport in structured bacterial communities. Using Pseudomonas aeruginosa colonies as a model system, we discover that a large-scale and temporally evolving open-channel system spontaneously develops in the colony via shear-induced banding. Fluid flows in the open channels support high-speed (up to 450 µm/s) transport of cells and outer membrane vesicles over centimeters, and help to eradicate colonies of a competing species Staphylococcus aureus. The open channels are reminiscent of human-made canals for cargo transport, and the channel flows are driven by interfacial tension mediated by cell-secreted biosurfactants. The spatial-temporal dynamics of fluid flows in the open channels are qualitatively described by flow profile measurement and mathematical modeling. Our findings demonstrate that mechanochemical coupling between interfacial force and biosurfactant kinetics can coordinate large-scale material transport in primitive life forms, suggesting a new principle to engineer self-organized microbial communities.


Assuntos
Microbiota , Infecções Estafilocócicas , Animais , Humanos , Pseudomonas aeruginosa/fisiologia , Staphylococcus aureus/fisiologia , Infecções Estafilocócicas/microbiologia , Bactérias
18.
Nature ; 609(7925): 166-173, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35948634

RESUMO

During infection, inflammatory monocytes are thought to be key for bacterial eradication, but this is hard to reconcile with the large numbers of neutrophils that are recruited for each monocyte that migrates to the afflicted tissue, and the much more robust microbicidal functions of the neutrophils. However, unlike neutrophils, monocytes have the capacity to convert to situationally specific macrophages that may have critical functions beyond infection control1,2. Here, using a foreign body coated with Staphylococcus aureus and imaging over time from cutaneous infection to wound resolution, we show that monocytes and neutrophils are recruited in similar numbers with low-dose infection but not with high-dose infection, and form a localization pattern in which monocytes surround the infection site, whereas neutrophils infiltrate it. Monocytes did not contribute to bacterial clearance but converted to macrophages that persisted for weeks after infection, regulating hypodermal adipocyte expansion and production of the adipokine hormone leptin. In infected monocyte-deficient mice there was increased persistent hypodermis thickening and an elevated leptin level, which drove overgrowth of dysfunctional blood vasculature and delayed healing, with a thickened scar. Ghrelin, which opposes leptin function3, was produced locally by monocytes, and reduced vascular overgrowth and improved healing post-infection. In sum, we find that monocytes function as a cellular rheostat by regulating leptin levels and revascularization during wound repair.


Assuntos
Leptina , Monócitos , Neovascularização Fisiológica , Infecções Estafilocócicas , Staphylococcus aureus , Cicatrização , Adipócitos/citologia , Adipócitos/metabolismo , Animais , Cicatriz , Grelina/metabolismo , Leptina/metabolismo , Macrófagos/citologia , Macrófagos/metabolismo , Camundongos , Monócitos/citologia , Monócitos/metabolismo , Neutrófilos/citologia , Neutrófilos/imunologia , Infecções Estafilocócicas/metabolismo , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/patologia , Staphylococcus aureus/fisiologia
19.
NPJ Biofilms Microbiomes ; 8(1): 62, 2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35909185

RESUMO

Biofilm engineering has emerged as a controllable way to fabricate living structures with programmable functionalities. The amyloidogenic proteins comprising the biofilms can be engineered to create self-assembling extracellular functionalized surfaces. In this regard, facultative amyloids, which play a dual role in biofilm formation by acting as adhesins in their native conformation and as matrix scaffolds when they polymerize into amyloid-like fibrillar structures, are interesting candidates. Here, we report the use of the facultative amyloid-like Bap protein of Staphylococcus aureus as a tool to decorate the extracellular biofilm matrix or the bacterial cell surface with a battery of functional domains or proteins. We demonstrate that the localization of the functional tags can be change by simply modulating the pH of the medium. Using Bap features, we build a tool for trapping and covalent immobilizing molecules at bacterial cell surface or at the biofilm matrix based on the SpyTag/SpyCatcher system. Finally, we show that the cell wall of several Gram-positive bacteria could be functionalized through the external addition of the recombinant engineered Bap-amyloid domain. Overall, this work shows a simple and modulable system for biofilm functionalization based on the facultative protein Bap.


Assuntos
Proteínas de Bactérias , Infecções Estafilocócicas , Amiloide/metabolismo , Proteínas Amiloidogênicas/genética , Proteínas Amiloidogênicas/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biofilmes , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/fisiologia
20.
J Dairy Sci ; 105(9): 7705-7718, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35879165

RESUMO

Mastitis in cattle is a major health problem as well as incurring high costs for the dairy industry. To assess the suitability of precision-cut bovine udder slices (PCBUS) for bovine mastitis studies, we infected PCBUS with 2 different Staphylococcus aureus strains. Accordingly, we investigated both the tissue response to infection based on immune mediators at the mRNA and protein levels and the invasion of bacteria within the tissue. The studied proteins represent immune mediators of early inflammation [IL-1ß, tumor necrosis factor-α (TNF-α), prostaglandin E2 (PGE2)] and showed a time-dependent increase in concentration. Infection of PCBUS with S. aureus resulted in increased expression of proinflammatory cytokines and chemokines such as TNF-α, C-C motif chemokine ligand 20 (CCL20), IL-1ß, IL-6, and IL-10, but not C-X-C motif chemokine ligand 8 (CXCL8), lingual antimicrobial peptide (LAP), or S100 calcium binding protein A9 (S100A9) at the mRNA level. To compare the data acquired with this model, we carried out investigations on primary bovine mammary epithelial cells. Our results showed that the immune responses of both models-PCBUS and primary bovine mammary epithelial cells-were similar. In addition, investigations using PCBUS enabled us to demonstrate adherence of bacteria in the physiological cell network. These findings support the use of PCBUS in studies designed to further understand the complex pathophysiological processes of infection and inflammation in bovine mastitis and to investigate alternative therapies for mastitis.


Assuntos
Doenças dos Bovinos , Mastite Bovina , Infecções Estafilocócicas , Animais , Bactérias , Bovinos , Doenças dos Bovinos/patologia , Quimiocinas , Células Epiteliais/microbiologia , Feminino , Fatores Imunológicos , Inflamação/patologia , Inflamação/veterinária , Ligantes , Glândulas Mamárias Animais/microbiologia , Mastite Bovina/microbiologia , RNA Mensageiro , Infecções Estafilocócicas/veterinária , Staphylococcus aureus/fisiologia , Fator de Necrose Tumoral alfa
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