RESUMO
Interest in developing antibacterial polymers as synthetic mimics of host defense peptides (HPDs) has accelerated in recent years to combat antibiotic-resistant bacterial infections. Positively charged moieties are critical in defining the antibacterial activity and eukaryotic toxicity of HDP mimics. Most examples have utilized primary amines or guanidines as the source of positively charged moieties, inspired by the lysine and arginine residues in HDPs. Here, we explore the impact of amine group variation (primary, secondary, or tertiary amine) on the antibacterial performance of HDP-mimicking ß-peptide polymers. Our studies show that a secondary ammonium is superior to either a primary ammonium or a tertiary ammonium as the cationic moiety in antibacterial ß-peptide polymers. The optimal polymer, a homopolymer bearing secondary amino groups, displays potent antibacterial activity and the highest selectivity (low hemolysis and cytotoxicity). The optimal polymer displays potent activity against antibiotic-resistant bacteria and high therapeutic efficacy in treating MRSA-induced wound infections and keratitis as well as low acute dermal toxicity and low corneal epithelial cytotoxicity. This work suggests that secondary amines may be broadly useful in the design of antibacterial polymers.
Assuntos
Aminas/química , Antibacterianos/uso terapêutico , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Peptídeos/uso terapêutico , Infecções Estafilocócicas/tratamento farmacológico , Infecção dos Ferimentos/tratamento farmacológico , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Escherichia coli/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Ceratite/tratamento farmacológico , Ceratite/microbiologia , Ceratite/patologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Camundongos , Testes de Sensibilidade Microbiana , Peptídeos/química , Peptídeos/farmacologia , Polímeros/química , Infecções Estafilocócicas/microbiologia , Infecção dos Ferimentos/microbiologiaRESUMO
BACKGROUND: A high mortality rate is associated with about 80% of all infections worldwide, mainly due to antimicrobial resistance. Various antimicrobial and cytotoxic activities have been proposed for Meliaceae species. This study aimed to evaluate the in vitro anti-virulence and cytotoxic effect of the leaf extracts of Aphanamixis polystachya, Toona ciliata and Melia azedarach against five MRSA strains and on three cancer cell lines, followed by biological correlation to their encompassed phytoconstituents. MATERIAL AND METHODS: We explored three plants of this family against a panel of Methicillin-resistant Staphylococcus aureus (MRSA) strains and several cancer cell lines to select the most promising candidates for further in vivo and preclinical studies. The phytochemical composition was evaluated by UHPLC-QTOF-MS untargeted profiling. Cell viability was assessed by SRB assay. Minimum Inhibitory Concentration was carried out by using the agar micro-dilution technique. Inhibition of biofilm formation and preformed biofilm disruption were assessed spectrophotomertically, according to the Sultan and Nabil method (2019). RESULTS: A total of 279 compounds were putatively annotated to include different phytochemical classes, such as flavonoids (108), limonoids/terpenoids (59), phenolic acids (49) and lower-molecular-weight phenolics (39). A. polystachya extract showed the most potent cytotoxic activity against Huh-7, DU-145 and MCF-7 cell lines (IC50 = 3, 3.5 and 13.4 µg mL-1, respectively), followed by M. azedarach, with no effect recorded for T. ciliata extract. Furthermore, both A. polystachya and M. azedarach extracts showed promising anti-virulence and antimicrobial activities, with A. polystachya being particularly active against MRSA. These two latter extracts could inhibit and disrupt the biofilm, formed by MRSA, at sub-lethal concentrations. Interestingly, the extracts inhibited hemolysin-α enzyme, thus protecting rabbit RBCs from lysis. A. polystachya extract reduced the pigmentation and catalase enzyme activity of tested pigmented strains better than M. azedarach at both tested sub-MICs. Consequently, susceptibility of the extract-treated cells to oxidant killing by 200 mM H2O2 increased, leading to faster killing of the cells within 120 min as compared to the extract-non-treated cells, likely due to the lower antioxidant-scavenging activity of cells exhibiting less staphyloxanthin production. CONCLUSION: These findings suggested that both A. polystachya and M. azedarach natural extracts are rich in bioactive compounds, mainly limonoids, phenolics and oxygenated triterpenoids, which can combat MRSA biofilm infections and could be considered as promising sources of therapeutic cytotoxic, antibiofilm and anti-virulence agents.
Assuntos
Antibacterianos/farmacologia , Meliaceae/química , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Compostos Fitoquímicos/análise , Compostos Fitoquímicos/farmacologia , Antibacterianos/química , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Biofilmes/efeitos dos fármacos , Linhagem Celular Tumoral , Cromatografia Líquida de Alta Pressão , Humanos , Espectrometria de Massas , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Testes de Sensibilidade Microbiana , Análise Multivariada , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Folhas de Planta/química , Virulência/efeitos dos fármacosRESUMO
The emergence of multidrug-resistant bacteria poses a threat to global health and necessitates the development of additional in vivo active antibiotics with diverse modes of action. Directly targeting menaquinone (MK), which plays an important role in bacterial electron transport, is an appealing, yet underexplored, mode of action due to a dearth of MK-binding molecules. Here we combine sequence-based metagenomic mining with a motif search of bioinformatically predicted natural product structures to identify six biosynthetic gene clusters that we predicted encode MK-binding antibiotics (MBAs). Their predicted products (MBA1-6) were rapidly accessed using a synthetic bioinformatic natural product approach, which relies on bioinformatic structure prediction followed by chemical synthesis. Among these six structurally diverse MBAs, four make up two new MBA structural families. The most potent member of each new family (MBA3, MBA6) proved effective at treating methicillin-resistant Staphylococcus aureus infection in a murine peritonitis-sepsis model. The only conserved feature present in all MBAs is the sequence 'GXLXXXW', which we propose represents a minimum MK-binding motif. Notably, we found that a subset of MBAs were active against Mycobacterium tuberculosis both in vitro and in macrophages. Our findings suggest that naturally occurring MBAs are a structurally diverse and untapped class of mechanistically interesting, in vivo active antibiotics.
Assuntos
Antibacterianos/metabolismo , Antibacterianos/uso terapêutico , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Vitamina K 2/metabolismo , Animais , Farmacorresistência Bacteriana Múltipla , Feminino , Humanos , Macrófagos/efeitos dos fármacos , Macrófagos/microbiologia , Metagenômica/métodos , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Camundongos , Testes de Sensibilidade Microbiana , Mycobacterium tuberculosis/efeitos dos fármacos , Peritonite/tratamento farmacológico , Peritonite/microbiologia , Infecções Estafilocócicas/tratamento farmacológico , Vitamina K 2/isolamento & purificaçãoRESUMO
The herbal plant Angelica gigas (A. gigas) has been used in traditional medicine in East Asian countries, and its chemical components are reported to have many pharmacological effects. In this study, we showed that a bioactive ingredient of A. gigas modulates the functional activity of macrophages and investigated its effect on inflammation using a sepsis model. Among 12 different compounds derived from A. gigas, decursinol angelate (DA) was identified as the most effective in suppressing the induction of TNF-α and IL-6 in murine macrophages. When mice were infected with a lethal dose of methicillin-resistant Staphylococcus aureus (MRSA), DA treatment improved the mortality and bacteremia, and attenuated the cytokine storm, which was associated with decreased CD38+ macrophage populations in the blood and liver. In vitro studies revealed that DA inhibited the functional activation of macrophages in the expression of pro-inflammatory mediators in response to microbial infection, while promoting the bacterial killing ability with an increased production of reactive oxygen species. Mechanistically, DA treatment attenuated the NF-κB and Akt signaling pathways. Intriguingly, ectopic expression of an active mutant of IKK2 released the inhibition of TNF-α production by the DA treatment, whereas the inhibition of Akt resulted in enhanced ROS production. Taken together, our experimental evidence demonstrated that DA modulates the functional activities of pro-inflammatory macrophages and that DA could be a potential therapeutic agent in the management of sepsis.
Assuntos
Benzopiranos/farmacologia , Butiratos/farmacologia , Macrófagos/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Sepse/patologia , Angelica/química , Angelica/metabolismo , Animais , Benzopiranos/química , Butiratos/química , Modelos Animais de Doenças , Interleucina-6/metabolismo , Estimativa de Kaplan-Meier , Lipopolissacarídeos/farmacologia , Macrófagos/citologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , NF-kappa B/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Células RAW 264.7 , Espécies Reativas de Oxigênio/metabolismo , Sepse/microbiologia , Sepse/mortalidade , Transdução de Sinais/efeitos dos fármacos , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Myristicafragrans Houtt. (Nutmeg) is a widely known folk medicine across several parts of Asia, particularly used in antimicrobial treatment. Bacterial resistance involves the expression of efflux pump systems (chromosomal norA and mepA) in methicillin-resistant Staphylococcus aureus (MRSA). Crude extract (CE) and essential oil (EO) obtained from nutmeg were applied as efflux pump inhibitors (EPIs), thereby enhancing the antimicrobial activity of the drugs they were used in. The major substances in CE and EO, which function as EPIs, in a descending order of % peak area include elemicin, myristicin, methoxyeugenol, myristicin, and asarone. Here, we investigated whether the low amount of CE and EO used as EPIs was sufficient to sensitize MRSA killing using the antibiotic ciprofloxacin, which acts as an efflux system. Interestingly, synergy between ciprofloxacin and CE or EO revealed the most significant viability of MRSA, depending on norA and mepA, the latter being responsible for EPI function of EO. Therefore, CE and EO obtained from nutmeg can act as EPIs in combination with substances that act as efflux systems, thereby ensuring that the MRSA strain is susceptible to antibiotic treatment.
Assuntos
Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Myristica/química , Óleos Voláteis/farmacologia , Infecções Estafilocócicas/tratamento farmacológico , Derivados de Alilbenzenos/farmacologia , Ciprofloxacina/farmacologia , Dioxolanos/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Humanos , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Testes de Sensibilidade Microbiana , Óleos Voláteis/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Sementes/química , Infecções Estafilocócicas/microbiologiaRESUMO
The emergence and spread of antimicrobial resistance have been of serious concern to human health and the management of bacterial infectious diseases. Effective treatment of these diseases requires the development of novel therapeutics, preferably free of side effects. In this regard, natural products are frequently conceived to be potential alternative sources for novel antibacterial compounds. Herein, we have evaluated the antibacterial activity of the epicarp extracts of the Malaysian cultivar of yellow rambutan fruit (Nephelium lappaceum L.) against six pathogens namely, Bacillus subtilis, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Pseudomonas aeruginosa, Klebsiella pneumoniae and Salmonella enterica. Among a series of solvent extracts, fractions of ethyl acetate and acetone have revealed significant activity towards all tested strains. Chemical profiling of these fractions, via HPLC, LC-MS and GC-MS, has generated a library of potentially bioactive compounds. Downstream virtual screening, pharmacological prediction, and receptor-ligand molecular dynamics simulation have eventually unveiled novel potential antibacterial compounds, which can be extracted for medicinal use. We report compounds like catechin, eplerenone and oritin-4-beta-ol to be computationally inhibiting the ATP-binding domain of the chaperone, DnaK of P. aeruginosa and MRSA. Thus, our work follows the objective to propose new antimicrobials capable of perforating the barrier of resistance posed by both the gram positives and the negatives.
Assuntos
Infecções Bacterianas/tratamento farmacológico , Produtos Biológicos/farmacologia , Extratos Vegetais/farmacologia , Sapindaceae/química , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/patogenicidade , Infecções Bacterianas/microbiologia , Infecções Bacterianas/patologia , Produtos Biológicos/química , Farmacorresistência Bacteriana/efeitos dos fármacos , Frutas/química , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/patogenicidade , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Testes de Sensibilidade Microbiana , Extratos Vegetais/química , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/patogenicidade , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/patogenicidadeRESUMO
PURPOSE: The production of alternative novel antimicrobial agents is considered an efficient way to cope with multidrug resistance among pathogenic bacteria. E50-52 and Ib-AMP4 antimicrobial peptides (AMPs) have illustrated great proven antibacterial effects. The aim of this study was recombinant production of these AMPs and investigation of their synergistic effects on methicillin-resistant Staphylococcus aureus (MRSA). METHOD: At first, the codon optimized sequences of the Ib-AMP4 (UniProt: 024006 (PRO_0000020721), and E50-52 (UniProtKB: P85148) were individually ligated into the pET-32α vector and transformed into E. coli. After the optimization of production and purification steps, the MIC (Minimum inhibitory concentration), time kill and growth kinetic tests of recombinant proteins were determined against MRSA. Finally, the in vivo wound healing efficiency was tested. RESULTS AND CONCLUSION: The recorded MIC of recombinant Trx-Ib-AMP4, Trx-E50-52 against MRSA bacterium were 0.375 and 0.0875 mg/mL respectively. The combination application of the produced AMPs by the checkerboard method confirmed their synergic activity. The results of the time-kill showed sharply decrease of the number of viable cells with over five time reductions in log10 CFU/mL by the combination of Trx-E50-52 and Trx-IbAMP4 at 2 × MIC within 240 min. The growth kinetic results confirmed the combination of Trx-E50-52 and Trx-IbAMP4 had much greater success in the reduction of over 50 % of MRSA suspensions' turbidity within the first hour. Wound healing assay and histological analysis of infected mice treated with Trx-Ib-AMP4 or Trx-E50-52 compared with those treated with a combination of Trx-Ib-AMP4 and Trx-E50-52 showed significant synergic effects.
Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Infecções Estafilocócicas/tratamento farmacológico , Infecções Cutâneas Estafilocócicas/tratamento farmacológico , Ferimentos não Penetrantes/tratamento farmacológico , Animais , Antibacterianos/biossíntese , Peptídeos Catiônicos Antimicrobianos/biossíntese , Peptídeos Catiônicos Antimicrobianos/genética , Clonagem Molecular , Sinergismo Farmacológico , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Masculino , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Testes de Sensibilidade Microbiana , Ratos , Ratos Wistar , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética , Proteínas Recombinantes/farmacologia , Pele/efeitos dos fármacos , Pele/lesões , Pele/microbiologia , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/patologia , Infecções Cutâneas Estafilocócicas/microbiologia , Infecções Cutâneas Estafilocócicas/patologia , Cicatrização/efeitos dos fármacos , Ferimentos não Penetrantes/microbiologia , Ferimentos não Penetrantes/patologiaRESUMO
The preparation of ointments from natural compounds is essential for accelerating infected wounds. This study investigated the effects of topical uses of gold nanoparticles (Au)/perlite (Au/Perl) nanocomposites (NCs) by the help of Urtica dioica extract and its chitosan-capped derivative (Chit) on methicillin-resistant Staphylococcus aureus (MRSA)-infected wound healing in a mouse model. Furthermore, Au/Perl/Chit nanocomposite was prepared using protonated chitosan solution. The physicochemical properties of the as-synthesized nanocomposites were also investigated. The effects of Au/Perl/Chit NC were assessed by antibacterial, histopathological parameters as well as molecular evaluations. Then, they were compared with synthetic agent of mupirocin. The results revealed that Au/Perl NC was mesoporous and spherical in a range of 13-15 nm. Topical administration of Au/Perl/Chit ointment accelerated wound healing by reducing bacteria colonization and wound rate enhancing collagen biosynthesis and re-epithelialization, the expressions of IL-10, PI3K, AKT, bFGF, and COL1A genes, which is in agreement with the obtained results for mupirocin. In conclusion, the results strongly demonstrated that administration of ointments prepared from Au/Perl and Au/Perl/Chit nanocomposites stimulates MRSA-infected wound healing by decreasing the length of healing time and regulating PI3K/AKT/bFGF signaling pathway and is a promising candidate in stimulating MRSA-infected wound regeneration.
Assuntos
Óxido de Alumínio/farmacologia , Antibacterianos/farmacologia , Antioxidantes/farmacologia , Quitosana/farmacologia , Compostos de Ouro/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Dióxido de Silício/farmacologia , Pele/efeitos dos fármacos , Infecções Cutâneas Estafilocócicas/tratamento farmacológico , Urtica dioica/metabolismo , Cicatrização/efeitos dos fármacos , Óxido de Alumínio/metabolismo , Animais , Antibacterianos/metabolismo , Antioxidantes/metabolismo , Proliferação de Células/efeitos dos fármacos , Quitosana/análogos & derivados , Quitosana/metabolismo , Modelos Animais de Doenças , Composição de Medicamentos , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Fibroblastos/microbiologia , Fibroblastos/patologia , Compostos de Ouro/metabolismo , Química Verde , Masculino , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Camundongos , Camundongos Endogâmicos BALB C , Células NIH 3T3 , Nanopartículas , Nanotecnologia , Transdução de Sinais , Dióxido de Silício/metabolismo , Pele/metabolismo , Pele/microbiologia , Pele/patologia , Infecções Cutâneas Estafilocócicas/metabolismo , Infecções Cutâneas Estafilocócicas/microbiologia , Infecções Cutâneas Estafilocócicas/patologia , Fatores de TempoRESUMO
Staphylococcus aureus can cause both acute and recurrent persistent infections such as peritonitis, endocarditis, abscesses, osteomyelitis, and chronic wound infections. Effective therapies to treat persistent disease are paramount. However, the mechanisms of S. aureus persistence are poorly understood. In this study, we performed a comprehensive and unbiased high-throughput mutant screen against a transposon-insertion mutant library of S. aureus USA300 and focused on the role of argJ encoding an acetyltransferase in the arginine biosynthesis pathway, whose transposon insertion caused a significant defect in persister formation using multiple drugs and stresses. Genetic complementation and arginine supplementation restored persistence in the argJ transposon insertion mutant while generation of mutations on the active site of the ArgJ protein caused a defect in persistence. Quantitative RT-PCR analysis showed that the genes encoded in the arg operon were over-expressed under drug stressed conditions and in stationary phase cultures. In addition, the argJ mutant had attenuated virulence in both mouse and C. elegans. Our studies identify a new mechanism of persistence mediated by arginine metabolism in S. aureus. These findings provide not only novel insights about the mechanisms of S. aureus persistence but also offer novel therapeutic targets that may help to develop more effective treatment of persistent S. aureus infections.
Assuntos
Acetiltransferases/genética , Proteínas de Bactérias/genética , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Infecções Estafilocócicas/microbiologia , Fatores de Virulência/genética , Acetiltransferases/metabolismo , Animais , Antibacterianos/farmacologia , Arginina/biossíntese , Proteínas de Bactérias/metabolismo , Vias Biossintéticas/genética , Caenorhabditis elegans , Elementos de DNA Transponíveis/genética , Modelos Animais de Doenças , Farmacorresistência Bacteriana/efeitos dos fármacos , Farmacorresistência Bacteriana/genética , Feminino , Biblioteca Gênica , Genes Bacterianos/efeitos dos fármacos , Ensaios de Triagem em Larga Escala , Humanos , Staphylococcus aureus Resistente à Meticilina/enzimologia , Staphylococcus aureus Resistente à Meticilina/genética , Camundongos , Mutação/efeitos dos fármacos , Virulência/efeitos dos fármacos , Virulência/genética , Fatores de Virulência/metabolismoRESUMO
RATIONALE: Methicillin-resistant Staphylococcus aureus (MRSA) has been established as an important cause of severe community-acquired pneumonia (CAP) with very high mortality. Panton-Valentine leukocidin (PVL) producing MRSA has been reported to be associated with necrotizing pneumonia and worse outcome. The incidence of community-acquired MRSA (CA-MRSA) pneumonia is very low, as only a few CA-MRSA pneumonia cases were reported in the last few years. We present a case of severe CAP caused by PVL-positive MRSA with ensuing septic shock. PATIENT CONCERNS: A 68-year-old male with no concerning medical history had developed a fever that reached 39.0°C, a productive cough that was sustained for 5 days, and hypodynamia. He was treated with azithromycin and alexipyretic in a nearby clinic for 2 days in which the symptoms were alleviated. However, 1 day later, the symptoms worsened, and he was taken to a local Chinese medicine hospital for traditional medicine treatment. However, his clinical condition deteriorated rapidly, and he then developed dyspnea and hemoptysis. DIAGNOSIS: CA-MRSA pneumonia and septic shock. The sputum culture showed MRSA. Polymerase chain reaction of MRSA isolates was positive for PVL genes. INTERVENTIONS: Mechanical ventilation, fluid resuscitation, and antibiotic therapy were performed. Antibiotic therapy included mezlocillin sodium/sulbactam sodium, linezolid, and oseltamivir. OUTCOMES: He died after 12âhours of treatment. LESSONS: This is a report of severe pneumonia due to PVL-positive CA-MRSA in a healthy adult. CA-MRSA should be considered a pathogen of severe CAP, especially when combined with septic shock in previously healthy individuals.
Assuntos
Pneumonia Associada a Assistência à Saúde/etiologia , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Infecções Estafilocócicas/complicações , Idoso , Antibacterianos/uso terapêutico , Tosse/etiologia , Pneumonia Associada a Assistência à Saúde/tratamento farmacológico , Pneumonia Associada a Assistência à Saúde/microbiologia , Humanos , Hipocinesia/etiologia , Linezolida/uso terapêutico , Masculino , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Mezlocilina/uso terapêutico , Oseltamivir/uso terapêutico , Choque Séptico/etiologia , Choque Séptico/mortalidade , Choque Séptico/fisiopatologiaRESUMO
Staphylococcus aureus is one of the most dreadful infectious agents, responsible for high mortality and morbidity in both humans and animals. The increased prevalence of multidrug-resistant (MDR) Staphylococcus aureus strains has limited the number of available treatment options, which calls for the development of alternative and effective modalities against MDR S. aureus. Endolysins are bacteriophage-derived antibacterials, which attack essential conserved elements of peptidoglycan that are vital for bacterial survival, making them promising alternatives or complements to existing antibiotics for tackling such infections. For developing endolysin lysin-methicillin-resistant-5 (LysMR-5) as an effective antimicrobial agent, we evaluated its physical and chemical characteristics, and its intrinsic antibacterial activity against staphylococcal strains, including methicillin-resistant Staphylococcus aureus (MRSA). In this study, we cloned, expressed, and purified LysMR-5 from S. aureus phage MR-5. In silico analysis revealed that LysMR-5 harbors two catalytic and one cell wall-binding domain. Biochemical characterization and LC-MS analysis showed that both catalytic domains were active and had no dependence on divalent ions for their action, Zn2+ exerted a negative effect. The optimal lytic activity of the endolysin was at 37 °C/pH 7.0 and in the presence of ≥ 300 mM concentration of NaCl. Circular dichroism (CD) demonstrated a loss in secondary structure with an increase in temperature confirming the thermosensitive nature of endolysin. Antibacterial assays revealed that LysMR-5 was active against diverse clinical isolates of staphylococci. It showed high lytic efficacy against S. aureus ATCC 43300, as an endolysin concentration as low as 15 µg/ml was sufficient to achieve maximum lytic activity within 30 min and it was further confirmed by scanning electron microscopy. Our results indicate that rapid and strong bactericidal activity of LysMR-5 makes it a valuable candidate for eradicating multidrug-resistant S. aureus.
Assuntos
Endopeptidases/farmacologia , Infecções Estafilocócicas/tratamento farmacológico , Fagos de Staphylococcus/genética , Animais , Antibacterianos/efeitos adversos , Antibacterianos/uso terapêutico , Humanos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Staphylococcus aureus Resistente à Meticilina/virologia , Peptidoglicano/genética , Infecções Estafilocócicas/microbiologiaRESUMO
Delafloxacin is a novel fluoroquinolone with activity against Gram-positive, Gram-negative, and atypical pathogens, including fluoroquinolone-nonsusceptible methicillin-resistant Staphylococcus aureus (MRSA). The microbiological results of a phase 3 clinical trial in adults with community-acquired pneumonia (CAP) comparing delafloxacin (300 mg intravenously [i.v.] with the option to switch to 450 mg orally every 12 h) to moxifloxacin (400 mg i.v. with the option to switch to 400 mg orally once a day [QD]) were determined. Patients from 4 continents, predominately Europe but also South America and Asia, were enrolled. The microbiological intent-to-treat (MITT) population included 520 patients, and 60.5% of these patients had a bacterial pathogen identified. Multiple diagnostic methods were employed, including culture, serology, PCR, and urinary antigen tests. Based on baseline MIC90 values, delafloxacin exhibited at least 16-fold greater activity than moxifloxacin for Gram-positive and fastidious Gram-negative pathogens. Delafloxacin retained activity against resistant phenotypes found in Streptococcus pneumoniae (penicillin-, macrolide-, and multiple-drug resistant), Haemophilus species (ß-lactamase producing and macrolide nonsusceptible), and S. aureus (MRSA and fluoroquinolone-nonsusceptible methicillin-susceptible S. aureus [MSSA]). The microbiological success rates were 92.7% for S. pneumoniae (87.5% for penicillin-resistant S. pneumoniae [PRSP]), 92.6% for S. aureus (100% for MRSA), 100% for Escherichia coli, 82.4% for Klebsiella pneumoniae, 100% for Klebsiella oxytoca, 100% for Moraxella catarrhalis, 91.7% for Haemophilus influenzae, 88.6% for Haemophilus parainfluenzae, 96.7% for Mycoplasma pneumoniae, 93.1% for Legionella pneumophila, and 100% for Chlamydia pneumoniae There was little correlation between MICs and outcomes, with a high proportion of favorable outcomes observed across all delafloxacin baseline MIC values. Delafloxacin may be considered a treatment option as monotherapy for CAP in adults, where broad-spectrum coverage including MRSA activity is desirable.
Assuntos
Antibacterianos/uso terapêutico , Fluoroquinolonas/uso terapêutico , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/patogenicidade , Macrolídeos/uso terapêutico , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Testes de Sensibilidade Microbiana , Moxifloxacina/uso terapêutico , Pneumonia Bacteriana/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/patogenicidade , Streptococcus pneumoniae/efeitos dos fármacos , Streptococcus pneumoniae/patogenicidadeRESUMO
There is an urgent need for new antibacterial strategies to overcome the emergence of antibiotic resistance. Antibacterial photodynamic therapy (APDT) may be an effective method to deliver photosensitizers for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. Here, we report that the photosensitizer hypocrellin A (HA) loaded into lipase-sensitive methoxy poly (ethylene glycol)-block-poly(ε-caprolactone) (mPEG-PCL) micelles showed high anti-MRSA activity in vitro and in vivo by PDT. Once the micelles come into contact with bacteria that secrete lipase, the PCL is degraded to release HA. Our results showed that the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of mPEG-PCL/HA micelles after light irradiation were 0.69 and 1.38â¯mg/L (HA concentration), respectively. In the dark, the MIC and MBC of the micelles were 250 and 500 mg/L (HA concentration), respectively. The fluorescent stain results further demonstrated the photodynamic antibacterial activity of mPEG-PCL/HA micelles. The survival rate of mice subjected to experimental acute peritonitis increased to 86% after treated with the micelles. The polymeric micelles showed low hemolytic activity and biocompatibility, simultaneously preventing aggregation in vivo and enhancing the water solubility of HA. Thus, the photosensitizer HA loaded micelles could be used as APDT for infections caused by bacteria without antibiotic resistance.
Assuntos
Lipase/química , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Perileno/análogos & derivados , Polímeros/química , Quinonas/química , Quinonas/uso terapêutico , Animais , Antibacterianos/química , Antibacterianos/uso terapêutico , Portadores de Fármacos/química , Feminino , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Camundongos , Micelas , Testes de Sensibilidade Microbiana , Perileno/química , Perileno/uso terapêutico , Fenol , FotoquimioterapiaRESUMO
Adults with cystic fibrosis (CF) frequently harbor Staphylococcus aureus, which is increasingly antibiotic resistant. Telavancin is a once-daily rapidly bactericidal antibiotic active against methicillin-, linezolid-, and ceftaroline-resistant S. aureus Because CF patients experience alterations in pharmacokinetics, the optimal dose of telavancin in this population is unknown. Adult CF patients (n = 18) admitted for exacerbations received 3 doses of telavancin 7.5 mg/kg of body weight (first 6 patients) or 10 mg/kg (final 12 patients) every 24 h (q24h). Population pharmacokinetic models with and without covariates were fitted using the nonparametric adaptive grid algorithm in Pmetrics. The final model was used to perform 5,000-patient Monte Carlo simulations for multiple telavancin doses. The best fit was a 2-compartment model describing the volume of distribution of the central compartment (Vc ) as a multiple of total body weight (TBW) and the volume of distribution of the central compartment scaled to total body weight (Vθ) normalized by the median observed value (Vc = Vθ × TBW/52.1) and total body clearance (CL) as a linear function of creatinine clearance (CRCL) (CL = CLNR + CLθ × CRCL), where CLNR represents nonrenal clearance and CLθ represents the slope term on CRCL to estimate renal clearance. The mean population parameters were as follows: Vθ, 4.92 ± 0.76 liters · kg-1; CLNR, 0.59 ± 0.30 liters · h-1; CLθ, 5.97 × 10-3 ± 1.24 × 10-3; Vp (volume of the peripheral compartment), 3.77 ± 1.41 liters; Q (intercompartmental clearance), 4.08 ± 2.17 liters · h-1 The free area under the concentration-time curve (fAUC) values for 7.5 and 10 mg/kg were 30 ± 4.6 and 52 ± 12 mg · h/liter, respectively. Doses of 7.5 mg/kg and 10 mg/kg achieved 76.5% and 100% probability of target attainment (PTA) at a fAUC/MIC threshold of >215, respectively, for MIC of ≤0.12 mg/liter. The probabilities of reaching the acute kidney injury (AKI) threshold AUC (763 mg · h · liter-1) for these doses were 0% and 0.96%, respectively. No serious adverse events occurred. Telavancin 10 mg/kg yielded optimal PTA and minimal risk of AKI, suggesting that this FDA-approved dose is appropriate to treat acute pulmonary exacerbations in CF adults. (The clinical trial discussed in this study has been registered at ClinicalTrials.gov under identifier NCT03172793.).
Assuntos
Aminoglicosídeos/farmacocinética , Aminoglicosídeos/uso terapêutico , Antibacterianos/farmacocinética , Antibacterianos/uso terapêutico , Fibrose Cística/tratamento farmacológico , Fibrose Cística/microbiologia , Lipoglicopeptídeos/farmacocinética , Lipoglicopeptídeos/uso terapêutico , Adulto , Algoritmos , Feminino , Humanos , Masculino , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Método de Monte Carlo , Estudos Prospectivos , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologiaRESUMO
Background & objectives: Although there are reports of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) across the globe, there is a lack of reliable data on hVISA in India. The present study was undertaken to determine the rate of hVISA among the methicillin-resistant Staphylococcus aureus (MRSA) isolates, and to compare the brain heart infusion agar with vancomycin 4 µg/ml (BHIV4) method with population analysis profile-area under the curve (PAP-AUC) method for the detection of hVISA and to study the distribution of mobile genetic element that carries methicillin-resistance gene SCCmec (Staphylococcal cassette chromosome mec) types among these isolates. Methods: BHIV4 and PAP-AUC methods were employed to detect hVISA among 500 clinical isolates of MRSA. SCCmec typing of these isolates was performed by multiplex polymerase chain reaction. The clinical presentation, treatment with vancomycin and outcome was documented for patients with hVISA. Results: The rate of hVISA was 12.4 per cent by PAP-AUC method. Sensitivity, specificity, PPV, NPV and kappa agreement of BHIV4 with PAP-AUC was 58.06, 93.15, 54.55, 94.01 per cent and 0.498, respectively. The isolation of hVISA was significantly (P<0.01) higher in patients admitted to intensive care units and wards than in patients attending the outpatient departments. Only 38 per cent of the patients received vancomycin as therapy. Majority of the hVISA isolates carried SCCmec type V or IV. Interpretation & conclusions: The rate of hVISA isolation in our study was 12.4 per cent. The sensitivity of the BHIV4 screening test was low, and was in moderate agreement with PAP-AUC test. SCCmec type V was the predominant type seen in half of the isolates. More studies need to be done in different parts of the country on a large number of isolates to confirm our findings.
Assuntos
Proteínas de Bactérias/genética , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Proteínas de Ligação às Penicilinas/genética , Infecções Estafilocócicas/genética , Vancomicina/uso terapêutico , Antibacterianos/efeitos adversos , Antibacterianos/uso terapêutico , Área Sob a Curva , Meios de Cultura/química , Meios de Cultura/farmacologia , Humanos , Índia/epidemiologia , Sequências Repetitivas Dispersas/genética , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Testes de Sensibilidade Microbiana , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Vancomicina/efeitos adversos , Resistência a Vancomicina/genéticaRESUMO
Patients often face the challenge of antibiotic-resistant bacterial infections and lengthy tissue reconstruction after surgery. Herein, human hair-melanosome derivatives (HHMs), comprising keratins and melanins, are developed using a simple "low-temperature alkali heat" method for potentially personalized therapy. The mulberry-shaped HHMs have an average width of â¼270 nm and an average length of â¼700 nm, and the negatively charged HHMs can absorb positively charged Lysozyme (Lyso) to form the HHMs-Lyso composites through electrostatic interaction. These naturally derived biodegradable nanostructures act as exogenous killers to eliminate methicillin-resistant Staphylococcus aureus (MRSA) infection with a high antibacterial efficacy (97.19 ± 2.39%) by synergistic action of photothermy and "Lyso-assisted anti-infection" in vivo. Additionally, HHMs also serve as endogenous regulators of collagen alpha chain proteins through the "protein digestion and absorption" signaling pathway to promote tissue reconstruction, which was confirmed by quantitative proteomic analysis in vivo. Notably, the 13 upregulated collagen alpha chain proteins in the extracellular matrix (ECM) after HHMs treatment demonstrated that keratin from HHMs in collagen-dependent regulatory processes serves as a notable contributor to augmented wound closure. The current paradigm of natural material-tissue interaction regulates the cell-ECM interaction by targeting cell signaling pathways to accelerate tissue repair. This work may provide insight into the protein-level pathways and the potential mechanisms involved in tissue repair.
Assuntos
Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Fototerapia , Proteômica , Infecções Estafilocócicas/tratamento farmacológico , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Linhagem Celular , Humanos , Melanossomas/efeitos dos fármacos , Meticilina/química , Meticilina/farmacologia , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Camundongos , Testes de Sensibilidade Microbiana , Muramidase/química , Muramidase/farmacologia , Nanoestruturas/química , Nanoestruturas/uso terapêutico , Infecções Estafilocócicas/genética , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/patologia , Cicatrização/efeitos dos fármacos , Cicatrização/genéticaRESUMO
Postinfluenza bacterial superinfections cause increased morbidity and mortality compared with singular infection with influenza during both pandemics and seasonal epidemics. Vaccines and current treatments provide limited benefit, a rationale to conduct studies utilizing alternative therapies. FY1 and an optimized version, MEDI8852, anti-influenza HA mAbs, have been shown to neutralize influenza virus during singular influenza infection. MEDI4893*, an anti-Staphylococcus aureus α-toxin mAb, has been shown to improve survival when administered prophylactically prior to S. aureus pneumonia. Our objective was to determine if mAbs can improve survival during postinfluenza bacterial pneumonia. We administered FY1 in a murine model of postinfluenza methicillin-resistant S. aureus (MRSA) pneumonia and observed improved survival rates when given early during the course of influenza infection. Our findings indicate decreased lung injury and increased uptake and binding of bacteria by macrophages in the mice that received FY1 earlier in the course of influenza infection, corresponding to decreased bacterial burden. We also observed improved survival when mice were treated with a combination of FY1 and MEDI4893* late during the course of postinfluenza MRSA pneumonia. In conclusion, both FY1 and MEDI4893* prolong survival when used in a murine model of postinfluenza MRSA pneumonia, suggesting pathogen-specific mAbs as a possible therapeutic in the context of bacterial superinfection.
Assuntos
Antibacterianos/uso terapêutico , Antivirais/uso terapêutico , Influenza Humana/tratamento farmacológico , Pneumonia Estafilocócica/tratamento farmacológico , Superinfecção/tratamento farmacológico , Animais , Antibacterianos/farmacologia , Anticorpos Monoclonais/farmacologia , Anticorpos Monoclonais/uso terapêutico , Anticorpos Monoclonais Humanizados/farmacologia , Anticorpos Monoclonais Humanizados/uso terapêutico , Antivirais/farmacologia , Anticorpos Amplamente Neutralizantes/farmacologia , Anticorpos Amplamente Neutralizantes/uso terapêutico , Modelos Animais de Doenças , Quimioterapia Combinada/métodos , Humanos , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H1N1/patogenicidade , Influenza Humana/imunologia , Influenza Humana/mortalidade , Influenza Humana/virologia , Pulmão/imunologia , Pulmão/microbiologia , Pulmão/virologia , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Masculino , Staphylococcus aureus Resistente à Meticilina/imunologia , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Camundongos , Neutrófilos/efeitos dos fármacos , Neutrófilos/imunologia , Pneumonia Estafilocócica/imunologia , Pneumonia Estafilocócica/microbiologia , Pneumonia Estafilocócica/mortalidade , Superinfecção/imunologia , Superinfecção/microbiologia , Superinfecção/mortalidade , Análise de Sobrevida , Resultado do TratamentoRESUMO
The ever-growing global crisis of multidrug-resistant bacteria has triggered a tumult of activity in the design and development of antibacterial formulations. Here, atomically thin antimony selenide nanosheets (Sb2Se3 NSs), a minimal-toxic and low-cost semiconductor material, were explored as a high-performance two-dimensional (2D) antibacterial nanoagent via a liquid exfoliation strategy integrating cryo-pretreatment and polyvinyl pyrrolidone (PVP)-assisted exfoliation. When cultured with bacteria, the obtained PVP-capped Sb2Se3 NSs exhibited intrinsic long-term antibacterial capability, probably due to the reactive oxygen species generation and sharp edge-induced membrane cutting during physical contact between bacteria and nanosheets. Upon near-infrared laser irradiation, Sb2Se3 NSs achieved short-time hyperthermia sterilization because of strong optical absorption and high photothermal conversion efficiency. By virtue of the synergistic effects of these two broad-spectrum antibacterial mechanisms, Sb2Se3 NSs exhibited high-efficiency inhibition of conventional Gram-negative Escherichia coli, Gram-positive methicillin-resistant Staphylococcus aureus, and wild bacteria from a natural water pool. Particularly, these three categories of bacteria were completely eradicated after being treated with Sb2Se3 NSs (300 µM) plus laser irradiation for only 5 min. In vivo wound healing experiment further demonstrated the high-performance antibacterial effect. In addition, Sb2Se3 NSs depicted excellent biocompatibility due to the biocompatible element constitute and bioinert PVP modification. This work enlightened that atomically thin Sb2Se3 NSs hold great promise as a broad-spectrum 2D antibacterial nanoagent for various pathogenic bacterial infections.
Assuntos
Antimônio/farmacologia , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Antibacterianos/química , Antibacterianos/farmacologia , Antimônio/química , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Humanos , Hipertermia Induzida/métodos , Raios Infravermelhos , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Nanoestruturas/administração & dosagem , Nanoestruturas/química , Fototerapia , Povidona/químicaRESUMO
Recurrent epidemics of drug-resistant Staphylococcus aureus illustrate the rapid lapse of antibiotic efficacy following clinical implementation. Over the last decade, community-associated methicillin-resistant S. aureus (MRSA) has emerged as a dominant cause of infections, and this problem is amplified by the hyper-virulent nature of these isolates. Herein, we report the discovery of a fungal metabolite, apicidin, as an innovative means to counter both resistance and virulence. Owing to its breadth and specificity as a quorum-sensing inhibitor, apicidin antagonizes all MRSA agr systems in a non-biocidal manner. In skin challenge experiments, the apicidin-mediated abatement of MRSA pathogenesis corresponds with quorum-sensing inhibition at in vivo sites of infection. Additionally, we show that apicidin attenuates MRSA-induced disease by potentiating innate effector responses, particularly through enhanced neutrophil accumulation and function at cutaneous challenge sites. Together, these results indicate that apicidin treatment represents a strategy to limit MRSA virulence and promote host defense.
Assuntos
Imunidade Inata/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Peptídeos Cíclicos/farmacologia , Percepção de Quorum/efeitos dos fármacos , Infecções Estafilocócicas/imunologia , Animais , Células Cultivadas , Avaliação Pré-Clínica de Medicamentos , Feminino , Interações Hospedeiro-Patógeno/efeitos dos fármacos , Interações Hospedeiro-Patógeno/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Coelhos , Infecções Estafilocócicas/microbiologia , Virulência/efeitos dos fármacosRESUMO
BACKGROUND: Multi-drug resistance in microorganisms is a serious problem at national as well as at a global level. Many researches have suggested alternatives to antibiotics with minimal or no major side effects. LAB is one of the most human-friendly probiotic strains known to mankind from times immemorial. With the objective to deal with progressing antibiotic resistance among microorganisms, the present work demonstrates the inhibitory activity of LAB consortium against MDR clinical isolates. METHODS: Total of nine hospital isolates of staphylococci were obtained and distinguished as S.aureus and coagulase-negative Staphylococcus (CoNS) based on their ability to ferment mannitol and form clumping with citrated plasma. All the test organisms were tested for antibiotic sensitivity with HiMedia (India) Octadisc Combi 92. Sets of L .plantarum, L .acidophilus and L.casei var. rhamnosus were prepared and tested against a standard culture of S.aureus NCIM 2129 by agar well diffusion method. To identify the primary source of substances responsible for inhibitory action, whole broth, cell-free supernatant, and cell lysate was prepared from the above-mentioned set. These were tested for their inhibitory action initially against standard S.aureus NCIM 2127, followed by clinical isolates. RESULTS: The antibiotic sensitivity profile revealed that all clinical isolates were multi-drug resistant. The maximum inhibitory potential was seen in a combination of the three LAB in the ratio 1:1:1. Highest antagonistic activity was observed with whole broth and cell lysate of LAB consortium. In liquid broth assay, the cell lysate of LAB consortium astoundingly exhibited up to 85% inhibition of multi-drug resistant Staphylococcus isolates. CONCLUSIONS: Our results suggest antagonistic role of LAB metabolites against methicillin resistant staphylococci.