Isopropoxy Benzene Guanidine Kills Staphylococcus aureus Without Detectable Resistance

Serious infections caused by multidrug-resistant Staphylococcus aureus clearly urge the development of new antimicrobial agents. Drug repositioning has emerged as an alternative approach that enables us to rapidly identify effective drugs. We first reported a guanidine compound, isopropoxy benzene guanidine, had potent antibacterial activity against S. aureus. Unlike conventional antibiotics, repeated use of isopropoxy benzene guanidine had a lower probability of resistance section. We found that isopropoxy benzene guanidine triggered membrane damage by disrupting the cell membrane potential and cytoplasmic membrane integrity. Furthermore, we demonstrated that isopropoxy benzene guanidine is capable of treating invasive MRSA infections in vivo studies. These findings provided strong evidence that isopropoxy benzene guanidine represents a new chemical lead for novel antibacterial agent against multidrug-resistant S. aureus infections.

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Isopropoxy benzene guanidine kills Staphylococcus aureus without detectable resistance

10.1101/2020.03.10.986687 ◽

2020 ◽

Author(s):

Xiufeng Zhang ◽

Xianfeng Peng ◽

Yixing Lu ◽

Jie Hao ◽

Fangping Li ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Drug Repurposing ◽

Multidrug Resistant ◽

Resistant Bacteria ◽

Health Crisis ◽

Pyrimidine Synthesis ◽

Conventional Antibiotics ◽

Induced Changes ◽

Effective Drugs

AbstractAntibiotic resistance is a serious public health crisis. The challenge caused by Staphylococcus aureus infections clearly urges the development of novel antimicrobial therapy. Drug repurposing has emerged as an alternative approach to rapidly identify effective drugs against multidrug-resistant bacteria. Recently, substituted benzene guanidine compounds have been used as leading structures to discover new promising drugs in both synthetic and medicinal chemistry. We investigated the antimicrobial activity of an analog of substituted benzene guanidine compounds (isopropoxy benzene guanidine) and further explored its antibacterial mechanism against S. aureus. Isopropoxy benzene guanidine had a MIC of 0.125-4μg/ml against S. aureus and displayed potent activity against S. aureus by disrupting cell membrane. Unlike conventional antibiotics, repeated use of isopropoxy benzene guanidine had a low probability of resistance section. The most substantial isopropoxy benzene guanidine-induced changes occurred in transcript levels of membrane transport functions-regulated genes, and genes involved in purine- and pyrimidine-synthesis pathway and virulence factors. Furthermore, in vivo studies demonstrated that isopropoxy benzene guanidine is capable of treating invasive MRSA infections. These findings provided strong evidence that isopropoxy benzene guanidine represents a new chemical lead for novel antibacterial agent against multidrug-resistant S. aureus infections.

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Design, Overproduction and Purification of the Chimeric Phage Lysin MLTphg Fighting against Staphylococcus aureus

Processes ◽

10.3390/pr8121587 ◽

2020 ◽

Vol 8 (12) ◽

pp. 1587

Author(s):

Feng Wang ◽

Xiaohang Liu ◽

Zhengyu Deng ◽

Yao Zhang ◽

Xinyu Ji ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Bacterial Infections ◽

Antimicrobial Agents ◽

Multidrug Resistant ◽

Resistant Bacteria ◽

Antibiotic Resistant ◽

E Coli ◽

Conventional Antibiotics ◽

Phage Lysin ◽

Shed Light

With the increasing spread of multidrug-resistant bacterial pathogens, it is of great importance to develop alternatives to conventional antibiotics. Here, we report the generation of a chimeric phage lysin, MLTphg, which was assembled by joining the lysins derived from Meiothermus bacteriophage MMP7 and Thermus bacteriophage TSP4 with a flexible linker via chimeolysin engineering. As a potential antimicrobial agent, MLTphg can be obtained by overproduction in Escherichia coli BL21(DE3) cells and the following Ni-affinity chromatography. Finally, we recovered about 40 ± 1.9 mg of MLTphg from 1 L of the host E. coli BL21(DE3) culture. The purified MLTphg showed peak activity against Staphylococcus aureus ATCC6538 between 35 and 40 °C, and maintained approximately 44.5 ± 2.1% activity at room temperature (25 °C). Moreover, as a produced chimera, it exhibited considerably improved bactericidal activity against Staphylococcus aureus (2.9 ± 0.1 log10 reduction was observed upon 40 nM MLTphg treatment at 37 °C for 30 min) and also a group of antibiotic-resistant bacteria compared to its parental lysins, TSPphg and MMPphg. In the current age of growing antibiotic resistance, our results provide an engineering basis for developing phage lysins as novel antimicrobial agents and shed light on bacteriophage-based strategies to tackle bacterial infections.

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Arginine Is a Critical Substrate for the Pathogenesis of Pseudomonas aeruginosa in Burn Wound Infections

mBio ◽

10.1128/mbio.02160-16 ◽

2017 ◽

Vol 8 (2) ◽

Cited By ~ 16

Author(s):

Jake Everett ◽

Keith Turner ◽

Qiuxian Cai ◽

Vernita Gordon ◽

Marvin Whiteley ◽

...

Keyword(s):

Antimicrobial Agents ◽

Hospital Setting ◽

Multidrug Resistant ◽

Burn Patients ◽

Burn Wound ◽

Burn Wounds ◽

Resistant Strains ◽

High Doses ◽

Ubiquitous Presence

ABSTRACT Environmental conditions affect bacterial behavior and can greatly influence the course of an infection. However, the environmental cues that elicit bacterial responses in specific infection sites are relatively unknown. Pseudomonas aeruginosa is ubiquitous in nature and typically innocuous. However, it is also one of the most prevalent causes of fatal sepsis in burn wound patients. The aim of this study was to determine the impact of environmental factors, specifically the availability of arginine, on the pathogenesis of P. aeruginosa in burn wound infections. Comparison of burned versus noninjured tissue revealed that l-arginine (l-Arg) was significantly depleted in burn wounds as a consequence of elevated arginase produced by myeloid-derived suppressor cells. We also observed that l-Arg was a potent chemoattractant for P. aeruginosa, and while low concentrations of l-Arg increased P. aeruginosa’s swimming motility, high concentrations resulted in diminished swimming. Based on these observations, we tested whether the administration of exogenous l-Arg into the burn wound could attenuate the virulence of P. aeruginosa in thermally injured mice. Administration of l-Arg resulted in decreased P. aeruginosa spread and sepsis and increased animal survival. Taken together, these data demonstrate that the availability of environmental arginine greatly influences the virulence of P. aeruginosa in vivo and may represent a promising phenotype-modulating tool for future therapeutic avenues. IMPORTANCE Despite our growing understanding of the pathophysiology of burn wounds and the evolution of techniques and practices to manage infections, sepsis remains a significant medical concern for burn patients. P. aeruginosa continues to be a leader among all causes of bacteremic infections due to its tendency to cause complications in immunocompromised patients and its ubiquitous presence in the hospital setting. With the unforgiving emergence of multidrug-resistant strains, it is critical that alternative strategies to control or prevent septic infections in burn patients be developed in parallel with novel antimicrobial agents. In this study, we observed that administration of l-Arg significantly reduced bacterial spread and sepsis in burned mice infected with P. aeruginosa. Given the safety of l-Arg in high doses and its potential wound-healing benefits, this conditionally essential amino acid may represent a useful tool to modulate bacterial behavior in vivo and prevent sepsis in burn patients. IMPORTANCE Despite our growing understanding of the pathophysiology of burn wounds and the evolution of techniques and practices to manage infections, sepsis remains a significant medical concern for burn patients. P. aeruginosa continues to be a leader among all causes of bacteremic infections due to its tendency to cause complications in immunocompromised patients and its ubiquitous presence in the hospital setting. With the unforgiving emergence of multidrug-resistant strains, it is critical that alternative strategies to control or prevent septic infections in burn patients be developed in parallel with novel antimicrobial agents. In this study, we observed that administration of l-Arg significantly reduced bacterial spread and sepsis in burned mice infected with P. aeruginosa. Given the safety of l-Arg in high doses and its potential wound-healing benefits, this conditionally essential amino acid may represent a useful tool to modulate bacterial behavior in vivo and prevent sepsis in burn patients.

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Activity of Debio1452, a FabI Inhibitor with Potent Activity against Staphylococcus aureus and Coagulase-Negative Staphylococcus spp., Including Multidrug-Resistant Strains

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.05119-14 ◽

2015 ◽

Vol 59 (5) ◽

pp. 2583-2587 ◽

Cited By ~ 20

Author(s):

Robert K. Flamm ◽

Paul R. Rhomberg ◽

Nachum Kaplan ◽

Ronald N. Jones ◽

David J. Farrell

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Agents ◽

Fatty Acid Biosynthesis ◽

Multidrug Resistant ◽

Coagulase Negative Staphylococcus ◽

Significant Activity ◽

Coagulase Negative Staphylococci ◽

Content Type ◽

Mrsa Strains ◽

Human Infections

ABSTRACTStaphylococcus aureusand coagulase-negative staphylococci (CoNS) are responsible for a wide variety of human infections. The investigational antibacterial Debio1450 (previously AFN-1720), a prodrug of Debio1452 (previously AFN-1252), specifically targets staphylococci without significant activity against other Gram-positive or Gram-negative species. Debio1452 inhibits FabI, an enzyme critical to fatty acid biosynthesis in staphylococci. The activity of Debio1452 against CoNS, methicillin-susceptibleS. aureus(MSSA), and methicillin-resistantS. aureus(MRSA), including significant clones, was determined. A globally diverse collection of 574 patient isolates from 35 countries was tested that included CoNS (6 species, 103 strains), MSSA (154 strains), MRSA (163 strains), and molecularly characterized strains (includingspa-typed MRSA clones; 154 strains). The isolates were tested for susceptibility by CLSI broth microdilution methods against Debio1452 and 10 comparators. The susceptibility rates for the comparators were determined using CLSI and EUCAST breakpoint criteria. AllS. aureusand CoNS strains were inhibited by Debio1452 concentrations of ≤0.12 and ≤0.5 μg/ml, respectively. The MIC50s for MSSA, MRSA, and molecularly characterized MRSA strains were 0.004 μg/ml, and the MIC90s ranged from 0.008 to 0.03 μg/ml. The MICs were higher for the CoNS isolates (MIC50/90, 0.015/0.12 μg/ml). AmongS. aureusstrains, resistance was common for erythromycin (61.6%), levofloxacin (49.0%), clindamycin (27.6%), tetracycline (15.7%), and trimethoprim-sulfamethoxazole (7.0%). Debio1452 demonstrated potent activity against MSSA, MRSA, and CoNS. Debio1452 showed significantly greater activity overall (MIC50, 0.004 μg/ml) than the other agents tested against these staphylococcal species, which included dominant MRSA clones and strains resistant to currently utilized antimicrobial agents.

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Efficient Killing of Multidrug-Resistant Intracellular Bacteria by AIEgens in Vivo

10.26434/chemrxiv.12579611 ◽

2020 ◽

Author(s):

Ying Li ◽

Fei Liu ◽

Jiangjiang Zhang ◽

Xiaoye Liu ◽

Peihong Xiao ◽

...

Keyword(s):

Membrane Damage ◽

Multidrug Resistant ◽

Host Cells ◽

Comparable Efficacy ◽

Intracellular Bacteria ◽

New Agents ◽

Immune Clearance ◽

Infected Cells ◽

Dose Levels

<a>Bacteria infected cells acting as “Trojan horses” not only protect bacteria from antibiotic therapies and immune clearance, but also increase the dissemination of pathogens from the initial sites of infection. Antibiotics are hard and insufficient to treat such hidden intracellular bacteria, especially the multidrug</a>-resistant (MDR) bacteria. Herein, aggregation-induced emission luminogens (AIEgens) such as TBPs showed potent broad-spectrum bactericidal activity against both <a></a><a>extracellular and intracellular</a> Gram-positive pathogens at low-dose levels. TBPs triggered reactive oxygen species (ROS)-mediated membrane damage to kill bacteria, regardless of light irradiation. Additionally, such AIEgens activated mitochondria dependent autophagy to eliminate intracellular bacteria in host cells. Compared to the routinely used vancomycin in clinics, TBPs showed comparable efficacy against methicillin-resistant Staphylococcus aureus (MRSA) in vivo. Our studies demonstrate that AIEgens are promising new agents for the treatment of MDR bacteria associated infections.

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Identification and Analysis of Bacterial Protein Secretion Inhibitors Utilizing a SecA-LacZ Reporter Fusion System

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.44.6.1418-1427.2000 ◽

2000 ◽

Vol 44 (6) ◽

pp. 1418-1427 ◽

Cited By ~ 35

Author(s):

L. E. Alksne ◽

P. Burgio ◽

W. Hu ◽

B. Feld ◽

M. P. Singh ◽

...

Keyword(s):

Protein Secretion ◽

Antimicrobial Agents ◽

Membrane Integrity ◽

Enzyme Linked Immunosorbent Assay ◽

Reporter Construct ◽

Central Protein ◽

Bona Fide ◽

Membrane Bound ◽

Protein Components

ABSTRACT Protein secretion is an essential process for bacterial growth, yet there are few if any antimicrobial agents which inhibit secretion. An in vivo, high-throughput screen to detect secretion inhibitors was developed based on the translational autoregulation of one of the central protein components, SecA. The assay makes use of a SecA-LacZ fusion reporter construct in Escherichia coli which is induced when secretion is perturbed. Several compounds, including two natural product extracts, which had the ability to induce the reporter fusion were identified and the MICs of these compounds forStaphylococcus aureus strain MN8 were found to be ≤128 μg/ml. Enzyme-linked immunosorbent assay, Western blotting, and immunoprecipitation techniques were used to analyze the affects of these compounds on protein secretion. Six representative compounds presented here appear to be bona fide secretion inhibitors but were found to have deleterious effects on membranes. It was concluded that, while the method described here for identifying inhibitors of secretion is valid, screens such as this, which are directed against the membrane-bound portion of a pathway, may preferentially identify compounds which affect membrane integrity.

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Novel Antibiotic Combinations of Diverse Subclasses for Effective Suppression of Extensively Drug-Resistant Methicillin-Resistant Staphylococcus aureus (MRSA)

International Journal of Microbiology ◽

10.1155/2020/8831322 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Shumyila Nasir ◽

Muhammad Sufyan Vohra ◽

Danish Gul ◽

Umm E Swaiba ◽

Maira Aleem ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Clavulanic Acid ◽

Antimicrobial Agents ◽

Methicillin Resistant Staphylococcus Aureus ◽

Multidrug Resistant ◽

Methicillin Resistant ◽

Development Of Resistance ◽

Amoxicillin Clavulanic Acid ◽

Combination Antibiotics ◽

Time Kill

The emergence of multidrug-resistant pathogens such as methicillin-resistant Staphylococcus aureus (MRSA), the chief etiological agent for a range of refractory infections, has rendered all β-lactams ineffective against it. The treatment process is further complicated with the development of resistance to glycopeptides, primary antibiotics for treatment of MRSA. Antibiotic combination therapy with existing antimicrobial agents may provide an immediate treatment option. Minimum inhibitory concentrations (MICs) of 18 different commercially available antibiotics were determined along with their 90 possible pairwise combinations and 64 triple combinations to filter out 5 best combinations. Time-Kill kinetics of these combinations were then analyzed to find collateral bactericidal combinations which were then tested on other randomly selected MRSA isolates. Among the top 5 combinations including levofloxacin-ceftazidime; amoxicillin/clavulanic acid-tobramycin; amoxicillin/clavulanic acid-cephradine; amoxicillin/clavulanic acid-ofloxacin; and piperacillin/tazobactam-tobramycin, three combinations were found to be collaterally effective. Levofloxacin-ceftazidime acted synergistically in 80% of the tested clinical MRSA isolates. First-line β-lactams of lower generations can be used effectively against MRSA infection when used in combination. Antibiotics other than glycopeptides may still work in combination.

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Macrocolony of NDM-1 Producing Enterobacter hormaechei subsp. oharae Generates Subpopulations with Different Features Regarding the Response of Antimicrobial Agents and Biofilm Formation

Pathogens ◽

10.3390/pathogens8020049 ◽

2019 ◽

Vol 8 (2) ◽

pp. 49 ◽

Cited By ~ 2

Author(s):

Flávia Roberta Brust ◽

Luana Boff ◽

Danielle da Silva Trentin ◽

Franciele Pedrotti Rozales ◽

Afonso Luís Barth ◽

...

Keyword(s):

Antimicrobial Agents ◽

Galleria Mellonella ◽

Polymyxin B ◽

Multidrug Resistant ◽

Biofilm Production ◽

Depth Study ◽

Enterobacter Hormaechei ◽

Type 3

Enterobacter cloacae complex has been increasingly recognized as a nosocomial pathogen representing the third major Enterobacteriaceae species involved with infections. This study aims to evaluate virulence and antimicrobial susceptibility of subpopulations generated from macrocolonies of NDM-1 producing Enterobacter hormaechei clinical isolates. Biofilm was quantified using crystal violet method and fimbrial genes were investigated by PCR. Susceptibility of antimicrobials, alone and combined, was determined by minimum inhibitory concentration and checkerboard assays, respectively. Virulence and efficacy of antimicrobials were evaluated in Galleria mellonella larvae. Importantly, we verified that some subpopulations that originate from the same macrocolony present different biofilm production ability and distinct susceptibility to meropenem due to the loss of blaNDM-1 encoding plasmid. A more in-depth study was performed with the 798 macrocolony subpopulations. Type 3 fimbriae were straightly related with biofilm production; however, virulence in larvae was not statistically different among subpopulations. Triple combination with meropenem–rifampicin–polymyxin B showed in vitro synergistic effect against all subpopulations; while in vivo this treatment showed different efficacy rates for 798-1S and 798-4S subpopulations. The ability of multidrug resistant E. hormaechei isolates in generating bacterial subpopulations presenting different susceptible and virulence mechanisms are worrisome and may explain why these infections are hardly overcome.

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Efficacy of NZ2114, a Novel Plectasin-Derived Cationic Antimicrobial Peptide Antibiotic, in Experimental Endocarditis Due to Methicillin-Resistant Staphylococcus aureus

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00453-11 ◽

2011 ◽

Vol 55 (11) ◽

pp. 5325-5330 ◽

Cited By ~ 38

Author(s):

Yan Q. Xiong ◽

Wessam Abdel Hady ◽

Antoine Deslandes ◽

Astrid Rey ◽

Laurent Fraisse ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Maximum Effect ◽

Peptide Antibiotic ◽

Time Curve ◽

Cationic Antimicrobial Peptide ◽

Unbound Fraction ◽

Methicillin Resistant ◽

Content Type ◽

Conventional Antibiotics

ABSTRACTCationic antimicrobial peptides (CAPs) play important roles in host immune defenses. Plectasin is a defensin-like CAP isolated from the saprophytic fungusPseudoplectania nigrella. NZ2114 is a novel variant of plectasin with potent activity against Gram-positive bacteria. In this study, we investigated (i) thein vivopharmacokinetic and pharmacodynamic (PK/PD) characteristics of NZ2114 and (ii) thein vivoefficacy of NZ2114 in comparison with those of two conventional antibiotics, vancomycin or daptomycin, in an experimental rabbit infective endocarditis (IE) model due to a methicillin-resistantStaphylococcus aureus(MRSA) strain (ATCC 33591). All NZ2114 regimens (5, 10, and 20 mg/kg of body weight, intravenously [i.v.], twice daily for 3 days) significantly decreased MRSA densities in cardiac vegetations, kidneys, and spleen versus those in untreated controls, except in one scenario (5 mg/kg, splenic MRSA counts). The efficacy of NZ2114 was clearly dose dependent in all target tissues. At 20 mg/kg, NZ2114 showed a significantly greater efficacy than vancomycin (P< 0.001) and an efficacy similar to that of daptomycin. Of importance, only NZ2114 (in 10- and 20-mg/kg regimens) prevented posttherapy relapse in cardiac vegetations, kidneys, and spleen, while bacterial counts in these target tissues continued to increase in vancomycin- and daptomycin-treated animals. Thesein vivoefficacies were equivalent and significantly correlated with three PK indices investigated:fCmax/MIC (the maximum concentration of the free, unbound fraction of a drug in serum divided by the MIC),fAUC/MIC (where AUC is the area under the concentration-time curve), andf%T>MIC(%T>MICis the cumulative percentage of a 24-h period that the drug concentration exceeds the MIC under steady-state pharmacokinetic conditions), as analyzed by a sigmoid maximum-effect (Emax) model (R2> 0.69). The superior efficacy of NZ2114 in this MRSA IE model suggests the potential for further development of this compound for treating serious MRSA infections.

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New Antimicrobial Bioactivity against Multidrug-Resistant Gram-Positive Bacteria of Kinase Inhibitor IMD0354

Antibiotics ◽

10.3390/antibiotics9100665 ◽

2020 ◽

Vol 9 (10) ◽

pp. 665

Author(s):

Iliana E Escobar ◽

Alexis White ◽

Wooseong Kim ◽

Eleftherios Mylonakis

Keyword(s):

Staphylococcus Aureus ◽

Kinase Inhibitor ◽

Cell Attachment ◽

Multidrug Resistant ◽

Resistant Bacteria ◽

Gram Positive ◽

C Elegans ◽

Vancomycin Resistant ◽

High Concentrations

Multidrug-resistant pathogens pose a serious threat to human health. For decades, the antibiotic vancomycin has been a potent option when treating Gram-positive multidrug-resistant infections. Nonetheless, in recent decades, we have begun to see an increase in vancomycin-resistant bacteria. Here, we show that the nuclear factor-kappa B (NF-κB) inhibitor N-[3,5-Bis(trifluoromethyl)phenyl]-5-chloro-2-hydroxybenzamide (IMD0354) was identified as a positive hit through a Caenorhabditis elegans–methicillin-resistant Staphylococcus aureus (MRSA) infection screen. IMD0354 was a potent bacteriostatic drug capable of working at a minimal inhibitory concentration (MIC) as low as 0.06 µg/mL against various vancomycin-resistant strains. Interestingly, IMD0354 showed no hemolytic activity at concentrations as high as 16 µg/mL and is minimally toxic to C. elegans in vivo with 90% survival up to 64 µg/mL. In addition, we demonstrated that IMD0354′s mechanism of action at high concentrations is membrane permeabilization. Lastly, we found that IMD0354 is able to inhibit vancomycin-resistant Staphylococcus aureus (VRSA) initial cell attachment and biofilm formation at sub-MIC levels and above. Our work highlights that the NF-κB inhibitor IMD0354 has promising potential as a lead compound and an antimicrobial therapeutic candidate capable of combating multidrug-resistant bacteria.

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