scholarly journals Discovery of a novel antibacterial protein CB6-C to target methicillin-resistant Staphylococcus aureus

2022 ◽  
Vol 21 (1) ◽  
Author(s):  
Haipeng Zhang ◽  
Jingrui Chen ◽  
Yuehua Liu ◽  
Qijun Xu ◽  
Muhammad Inam ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Infections ◽  
Therapeutic Index ◽  
Lipoteichoic Acid ◽  
Multidrug Resistant ◽  
In Vivo Models ◽  
Methicillin Resistant ◽  
Antibacterial Protein ◽  
High Therapeutic Index

AbstractGiven a serious threat of multidrug-resistant bacterial pathogens to global healthcare, there is an urgent need to find effective antibacterial compounds to treat drug-resistant bacterial infections. In our previous studies, Bacillus velezensis CB6 with broad-spectrum antibacterial activity was obtained from the soil of Changbaishan, China. In this study, with methicillin-resistant Staphylococcus aureus as an indicator bacterium, an antibacterial protein was purified by ammonium sulfate precipitation, Sephadex G-75 column, QAE-Sephadex A 25 column and RP-HPLC, which demonstrated a molecular weight of 31.405 kDa by SDS-PAGE. LC–MS/MS analysis indicated that the compound was an antibacterial protein CB6-C, which had 88.5% identity with chitosanase (Csn) produced by Bacillus subtilis 168. An antibacterial protein CB6-C showed an effective antimicrobial activity against gram-positive bacteria (in particular, the MIC for MRSA was 16 μg/mL), low toxicity, thermostability, stability in different organic reagents and pH values, and an additive effect with conventionally used antibiotics. Mechanistic studies showed that an antibacterial protein CB6-C exerted anti-MRSA activity through destruction of lipoteichoic acid (LTA) on the cell wall. In addition, an antibacterial protein CB6-C was efficient in preventing MRSA infections in in vivo models. In conclusion, this protein CB6-C is a newly discovered antibacterial protein and has the potential to become an effective antibacterial agent due to its high therapeutic index, safety, nontoxicity and great stability.

Discovery of a Novel Antibacterial Protein CB6-C to Target Methicillin-Resistant Staphylococcus Aureus

2021 ◽  
Author(s):  
Haipeng Zhang ◽  
Yuehua Liu ◽  
Qijun Xu ◽  
Muhammad Inam ◽  
Chengguang He ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Therapeutic Index ◽  
Lipoteichoic Acid ◽  
Multidrug Resistant ◽  
In Vivo Models ◽  
Organic Reagents ◽  
Antibacterial Protein ◽  
Gram Positive Bacteria ◽  
High Therapeutic Index

Abstract Given the serious threat of multidrug-resistant bacterial pathogens to global healthcare, there is an urgent need to find effective antibacterial compounds to treat drug-resistant bacterial infections. In our previous studies, Bacillus velezensis CB6 with broad-spectrum antibacterial activity was obtained from the soil of Changbaishan, China. In this study, with MRSA as an indicator bacterium, an antibacterial protein was purified by ammonium sulfate precipitation, a Sephadex G-75 column, a QAE-Sephadex A 25 column and RP-HPLC, which demonstrated a molecular weight of 31405.48 Da by SDS-PAGE. LC-MS/MS analysis indicated that the compound was an antibacterial protein CB6-C, which had 88.5% homology with chitosanase Csn produced by Bacillus subtilis 168. An antibacterial protein CB6-C showed an effective antimicrobial activity against gram-positive bacteria (in particular, the MIC for MRSA was 16 μg/mL), low toxicity, thermostability, stability in different organic reagents and pH values, and an additive effect with conventionally used antibiotics. Mechanistic studies showed that an antibacterial protein CB6-C exerted anti-MRSA activity through destruction of lipoteichoic acid (LTA) on the cell wall. In addition, an antibacterial protein CB6-C was efficient in preventing MRSA infections in In Vivo models. In conclusion, this protein CB6-C is a newly discovered antibacterial protein and has the potential to become an effective antibacterial agent due to its high therapeutic index, safety, nontoxicity and great stability.

scholarly journals Impact of Bicarbonate-β-Lactam Exposures on Methicillin-Resistant Staphylococcus aureus (MRSA) Gene Expression in Bicarbonate-β-Lactam-Responsive vs. Non-Responsive Strains

Genes ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1650
Author(s):  
Selvi C. Ersoy ◽  
Blake M. Hanson ◽  
Richard A. Proctor ◽  
Cesar A. Arias ◽  
Truc T. Tran ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Ex Vivo ◽  
In Vivo Models ◽  
Methicillin Resistant ◽  
Genetic Perturbations ◽  
Functional Relevance

Methicillin-resistant Staphylococcus aureus (MRSA) infections represent a difficult clinical treatment issue. Recently, a novel phenotype was discovered amongst selected MRSA which exhibited enhanced β-lactam susceptibility in vitro in the presence of NaHCO3 (termed ‘NaHCO3-responsiveness’). This increased β-lactam susceptibility phenotype has been verified in both ex vivo and in vivo models. Mechanistic studies to-date have implicated NaHCO3-mediated repression of genes involved in the production, as well as maturation, of the alternative penicillin-binding protein (PBP) 2a, a necessary component of MRSA β-lactam resistance. Herein, we utilized RNA-sequencing (RNA-seq) to identify genes that were differentially expressed in NaHCO3-responsive (MRSA 11/11) vs. non-responsive (COL) strains, in the presence vs. absence of NaHCO3-β-lactam co-exposures. These investigations revealed that NaHCO3 selectively repressed the expression of a cadre of genes in strain 11/11 known to be a part of the sigB-sarA-agr regulon, as well as a number of genes involved in the anchoring of cell wall proteins in MRSA. Moreover, several genes related to autolysis, cell division, and cell wall biosynthesis/remodeling, were also selectively impacted by NaHCO3-OXA exposure in the NaHCO3-responsive strain MRSA 11/11. These outcomes provide an important framework for further studies to mechanistically verify the functional relevance of these genetic perturbations to the NaHCO3-responsiveness phenotype in MRSA.

scholarly journals Activities of Clindamycin, Daptomycin, Doxycycline, Linezolid, Trimethoprim-Sulfamethoxazole, and Vancomycin against Community-Associated Methicillin-Resistant Staphylococcus aureus with Inducible Clindamycin Resistance in Murine Thigh Infection and In Vitro Pharmacodynamic Models

2008 ◽  
Vol 52 (6) ◽  
pp. 2156-2162 ◽  
Author(s):  
Kerry L. LaPlante ◽  
Steven N. Leonard ◽  
David R. Andes ◽  
William A. Craig ◽  
Michael J. Rybak
Keyword(s):  
Staphylococcus Aureus ◽  
Inoculum Size ◽  
In Vivo Model ◽  
Infection Model ◽  
Time Curve ◽  
In Vivo Models ◽  
Methicillin Resistant ◽  
Inducible Clindamycin Resistance

ABSTRACT Controversy exists about the most effective treatment options for community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) and about the ability of these strains to develop inducible resistance to clindamycin during therapy. Using both in vitro pharmacodynamic and murine thigh infection models, we evaluated and compared several antimicrobial compounds against CA-MRSA. Strains with inducible macrolide lincosamide-streptogramin type B (iMLSB) resistance and strains in which resistance was noninducible were evaluated. Two levels of inocula (105 and 107) were evaluated for clindamycin activity in the in vivo model. In both models, the antimicrobial evaluation was performed in triplicate, and bacterial quantification occurred over 72 h, with drug doses that were designed to simulate the free drug area-under-the-concentration-time curve values (fAUCs) obtained from human samples. When the activity of clindamycin against the iMLSB strains was evaluated, constitutive resistance was noted at 24 h (MIC of >256), and failure was noted at an inoculum of ≥106 in the in vivo models. However, at a low inoculum (105) in the murine thigh-infection model, clindamycin demonstrated modest activity, reducing the CFU/thigh count for clindamycin resistance-inducible strains at 72 h (0.45 to 1.3 logs). Overall, administration of daptomycin followed by vancomycin demonstrated the most significant kill against all strains in both models. Against the clindamycin noninducible strain, clindamycin and doxycycline demonstrated significant kill. Doxycycline, linezolid, and trimethoprim-sulfamethoxazide (not run in the murine model) demonstrated bacteriostatic activity against clindamycin resistance-inducible isolates. This study demonstrates that clindamycin's activity against the iMLSB strains tested is partially impacted by inoculum size. At present, there are several alternatives that appear promising for treating clindamycin resistance-inducible strains of CA-MRSA.

scholarly journals Combining the FtsZ-Targeting Prodrug TXA709 and the Cephalosporin Cefdinir Confers Synergy and Reduces the Frequency of Resistance in Methicillin-Resistant Staphylococcus aureus

2016 ◽  
Vol 60 (7) ◽  
pp. 4290-4296 ◽  
Author(s):  
Malvika Kaul ◽  
Lilly Mark ◽  
Ajit K. Parhi ◽  
Edmond J. LaVoie ◽  
Daniel S. Pilch
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Infections ◽  
Drug Dose ◽  
Drug Induced ◽  
Methicillin Resistant ◽  
Content Type ◽  
Vancomycin Resistant ◽  
Emergence Of Resistance

ABSTRACTCombination therapy of bacterial infections with synergistic drug partners offers distinct advantages over monotherapy. Among these advantages are (i) a reduction of the drug dose required for efficacy, (ii) a reduced potential for drug-induced toxicity, and (iii) a reduced potential for the emergence of resistance. Here, we describe the synergistic actions of the third-generation oral cephalosporin cefdinir and TXA709, a new, FtsZ-targeting prodrug that we have developed with improved pharmacokinetics and enhancedin vivoefficacy against methicillin-resistantStaphylococcus aureus(MRSA) relative to earlier agents. We show that the active product of TXA709 (TXA707) acts synergistically with cefdinirin vitroagainst clinical isolates of MRSA, vancomycin-intermediateS. aureus(VISA), vancomycin-resistantS. aureus(VRSA), and linezolid-resistantS. aureus(LRSA). In addition, relative to TXA707 alone, the combination of TXA707 and cefdinir significantly reduces or eliminates the detectable emergence of resistance. We also demonstrate synergyin vivowith oral administration of the prodrug TXA709 and cefdinir in mouse models of both systemic and tissue (thigh) infections with MRSA. This synergy reduces the dose of TXA709 required for efficacy 3-fold. Viewed as a whole, our results highlight the potential of TXA709 and cefdinir as a promising combination for the treatment of drug-resistant staphylococcal infections.

scholarly journals 5-Dodecanolide interferes with biofilm formation and reduces the virulence of Methicillin-resistant Staphylococcus aureus (MRSA) through up regulation of agr system

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Alaguvel Valliammai ◽  
Sivasamy Sethupathy ◽  
Arumugam Priya ◽  
Anthonymuthu Selvaraj ◽  
James Prabhanand Bhaskar ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Bacterial Infections ◽  
Pcr Analysis ◽  
High Morbidity ◽  
Healthy Human ◽  
Methicillin Resistant ◽  
Gene Expression Studies ◽  
Human Infections

Abstract Methicillin resistant Staphylococcus aureus (MRSA) is a predominant human pathogen with high morbidity that is listed in the WHO high priority pathogen list. Being a primary cause of persistent human infections, biofilm forming ability of S. aureus plays a pivotal role in the development of antibiotic resistance. Hence, targeting biofilm is an alternative strategy to fight bacterial infections. The present study for the first time demonstrates the non-antibacterial biofilm inhibitory efficacy of 5-Dodecanolide (DD) against ATCC strain and clinical isolates of S. aureus. In addition, DD is able to inhibit adherence of MRSA on human plasma coated Titanium surface. Further, treatment with DD significantly reduced the eDNA synthesis, autoaggregation, staphyloxanthin biosynthesis and ring biofilm formation. Reduction in staphyloxanthin in turn increased the susceptibility of MRSA to healthy human blood and H2O2 exposure. Quantitative PCR analysis revealed the induced expression of agrA and agrC upon DD treatment. This resulted down regulation of genes involved in biofilm formation such as fnbA and fnbB and up regulation of RNAIII, hld, psmα and genes involved in biofilm matrix degradation such as aur and nuc. Inefficacy of DD on the biofilm formation of agr mutant further validated the agr mediated antibiofilm potential of DD. Notably, DD was efficient in reducing the in vivo colonization of MRSA in Caenorhabditis elegans. Results of gene expression studies and physiological assays unveiled the agr mediated antibiofilm efficacy of DD.

scholarly journals Impact of a Novel Anticoccidial Analogue on Systemic Staphylococcus aureus Infection in a Bioluminescent Mouse Model

Antibiotics ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 65
Author(s):  
Hang Thi Nguyen ◽  
Henrietta Venter ◽  
Lucy Woolford ◽  
Kelly Young ◽  
Adam McCluskey ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Infections ◽  
Survival Rates ◽  
Multidrug Resistant ◽  
Chemical Diversity ◽  
Clinical Effects ◽  
Synergistic Activity ◽  
Survival Times ◽  
Methicillin Resistant ◽  
Oral Doses

In this study, we investigated the potential of an analogue of robenidine (NCL179) to expand its chemical diversity for the treatment of multidrug-resistant (MDR) bacterial infections. We show that NCL179 exhibits potent bactericidal activity, returning minimum inhibitory concentration/minimum bactericidal concentrations (MICs/MBCs) of 1–2 µg/mL against methicillin-resistant Staphylococcus aureus, MICs/MBCs of 1–2 µg/mL against methicillin-resistant S. pseudintermedius and MICs/MBCs of 2–4 µg/mL against vancomycin-resistant enterococci. NCL179 showed synergistic activity against clinical isolates and reference strains of Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa in the presence of sub-inhibitory concentrations of colistin, whereas NCL179 alone had no activity. Mice given oral NCL179 at 10 mg/kg and 50 mg/kg (4 × doses, 4 h apart) showed no adverse clinical effects and no observable histological effects in any of the organs examined. In a bioluminescent S. aureus sepsis challenge model, mice that received four oral doses of NCL179 at 50 mg/kg at 4 h intervals exhibited significantly reduced bacterial loads, longer survival times and higher overall survival rates than the vehicle-only treated mice. These results support NCL179 as a valid candidate for further development to treat MDR bacterial infections as a stand-alone antibiotic or in combination with existing antibiotic classes.

scholarly journals Phage Therapy: A Potential Novel Therapeutic Treatment of Methicillin-Resistant Staphylococcus aureus

2021 ◽  
Author(s):  
Logan Gildea ◽  
Joseph Ayariga ◽  
James Abugri ◽  
Robert Villafane
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Infections ◽  
Phage Therapy ◽  
Treatment Method ◽  
Multidrug Resistant ◽  
Bacterial Strains ◽  
Antibiotic Resistant ◽  
Methicillin Resistant ◽  
Novel Treatment ◽  
Resistant Bacterial Strain

The emergence of multidrug-resistant bacterial strains, especially in the clinical setting, has renewed interest in alternative treatment methods. The utilization of prokaryotic viruses in phage therapy has demonstrated potential as a novel treatment method against multidrug-resistant bacterial infections. As the post-antibiotic era quickly approaches, the development and standardization of phage therapy is critically relevant to public health. This review serves to highlight the development of phage therapy against methicillin-resistant Staphylococcus aureus (MRSA), an antibiotic-resistant bacterial strain responsible for severe clinical infections.

scholarly journals Erianin against Staphylococcus aureus Infection via Inhibiting Sortase A

Toxins ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 385 ◽  
Author(s):  
Ping Ouyang ◽  
Xuewen He ◽  
Zhong-Wei Yuan ◽  
Zhong-Qiong Yin ◽  
Hualin Fu ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Infections ◽  
Hydrophobic Interactions ◽  
Multidrug Resistant ◽  
Vital Role ◽  
Surface Proteins ◽  
Dynamics Simulation ◽  
Sortase A

With continuous emergence and widespread of multidrug-resistant Staphylococcus aureus infections, common antibiotics have become ineffective in treating these infections in the clinical setting. Anti-virulence strategies could be novel, effective therapeutic strategies against drug-resistant bacterial infections. Sortase A (srtA), a transpeptidase in gram-positive bacteria, can anchor surface proteins that play a vital role in pathogenesis of these bacteria. SrtA is known as a potential antivirulent drug target to treat bacterial infections. In this study, we found that erianin, a natural bibenzyl compound, could inhibit the activity of srtA in vitro (half maximal inhibitory concentration—IC50 = 20.91 ± 2.31 μg/mL, 65.7 ± 7.2 μM) at subminimum inhibitory concentrations (minimum inhibitory concentrations—MIC = 512 μg/mL against S. aureus). The molecular mechanism underlying the inhibition of srtA by erianin was identified using molecular dynamics simulation: erianin binds to srtA residues Ile182, Val193, Trp194, Arg197, and Ile199, forming a stable bond via hydrophobic interactions. In addition, the activities of S. aureus binding to fibronectin and biofilm formation were inhibited by erianin, when co-culture with S. aureus. In vivo, erianin could improve the survival in mice that infected with S. aureus by tail vein injection. Experimental results showed that erianin is a potential novel therapeutic compound against S. aureus infections via affecting srtA.

scholarly journals In silicoidentification of novel peptides with antibacterial activity against multidrug resistantStaphylococcus aureus

2019 ◽  
Author(s):  
Linda B Oyama ◽  
Hamza Olleik ◽  
Ana Carolina Nery Teixeira ◽  
Matheus M Guidini ◽  
James A Pickup ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Peptides ◽  
In Silico ◽  
Multidrug Resistant ◽  
Biofilm Inhibition ◽  
Methicillin Resistant ◽  
Drug Candidates ◽  
Wide Range

AbstractHerein we report the identification and characterisation of two linear antimicrobial peptides (AMPs), HG2 and HG4, with activity against a wide range of multidrug resistant (MDR) bacteria, especially methicillin resistantStaphylococcus aureus(MRSA) strains, a highly problematic group of Gram-positive bacteria in the hospital and community environment. To identify the novel AMPs presented here, we employed the classifier model design, a feature extraction method using molecular descriptors for amino acids for the analysis, visualization, and interpretation of AMP activities from a rumen metagenomic dataset. This allowed for thein silicodiscrimination of active and inactive peptides in order to define a small number of promising novel lead AMP test candidates for chemical synthesis and experimental evaluation.In vitrodata suggest that the chosen AMPs are fast acting, show strong biofilm inhibition and dispersal activity and are efficacious in anin vivomodel of MRSA USA300 infection, whilst showing little toxicity to human erythrocytes and human primary cell linesex vivo. Observations from biophysical AMP-lipid-interactions and electron microscopy suggest that the newly identified peptides interact with the cell membrane and may be involved in the inhibition of other cellular processes. Amphiphilic conformations associated with membrane disruption are also observed in 3D molecular modelling of the peptides. HG2 and HG4 both preferentially bind to MRSA total lipids rather than with human cell lipids indicating that HG4 may form superior templates for safer therapeutic candidates for MDR bacterial infections.Author SummaryWe are losing our ability to treat multidrug resistant (MDR) bacteria, otherwise known as superbugs. This poses a serious global threat to human health as bacteria are increasingly acquiring resistance to antibiotics. There is therefore urgent need to intensify our efforts to develop new safer alternative drug candidates. We emphasise the usefulness of complementing wet-lab andin silicotechniques for the rapid identification of new drug candidates from environmental samples, especially antimicrobial peptides (AMPs). HG2 and HG4, the AMPs identified in our study show promise as effective therapies for the treatment of methicillin resistantStaphylococcus aureusinfections bothin vitroandin vivowhilst having little cytotoxicity against human primary cells, a step forward in the fight against MDR infections.

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