scholarly journals Cerecidins, Novel Lantibiotics from Bacillus cereus with Potent Antimicrobial Activity

2014 ◽  
Vol 80 (8) ◽  
pp. 2633-2643 ◽  
Author(s):  
Jian Wang ◽  
Li Zhang ◽  
Kunling Teng ◽  
Shutao Sun ◽  
Zhizeng Sun ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Multidrug Resistant ◽  
Regulator Gene ◽  
Gram Positive ◽  
Content Type ◽  
Pcr Screening ◽  
Gram Positive Bacteria ◽  
Immunity Genes ◽  
Natural Variants ◽  
Vancomycin Resistant

ABSTRACTLantibiotics are ribosomally synthesized and posttranslationally modified antimicrobial peptides that are widely produced by Gram-positive bacteria, including many species of theBacillusgroup. In the present study, one novel gene cluster coding lantibiotic cerecidins was unveiled inBacillus cereusstrain As 1.1846 through genomic mining and PCR screening. The designatedcerlocus is different from that of conventional class II lantibiotics in that it included seven tandem precursorcerAgenes, one modification gene (cerM), two processing genes (cerTandcerP), one orphan regulator gene (cerR), and two immunity genes (cerFandcerE). In addition, one unprecedented quorum sensing component,comQXPA, was inserted betweencerMandcerR. The expression of cerecidins was not detected in this strain ofB. cereus, which might be due to repressed transcription ofcerM. We constitutively coexpressedcerAgenes andcerMinEscherichia coli, and purified precerecidins were proteolytically processed with the endoproteinase GluC and a truncated version of putative serine protease CerP. Thus, two natural variants of cerecidins A1 and A7 were obtained which contained two terminal nonoverlapping thioether rings rarely found in lantibiotics. Both cerecidins A1 and A7 were active against a broad spectrum of Gram-positive bacteria. Cerecidin A7, especially its mutant Dhb13A, showed remarkable efficacy against multidrug-resistantStaphylococcus aureus(MDRSA), vancomycin-resistantEnterococcus faecalis(VRE), and evenStreptomyces.

scholarly journals Activities of Oxadiazole Antibacterials against Staphylococcus aureus and Other Gram-Positive Bacteria

2018 ◽  
Vol 62 (8) ◽  
Author(s):  
Sara Ceballos ◽  
Choon Kim ◽  
Derong Ding ◽  
Shahriar Mobashery ◽  
Mayland Chang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Gram Positive ◽  
Methicillin Resistant ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Vancomycin Resistant Enterococci ◽  
Vancomycin Resistant ◽  
Mrsa Strains

ABSTRACT The activities of four oxadiazoles were investigated with 210 methicillin-resistant Staphylococcus aureus (MRSA) strains. MIC50 and MIC90 values of 1 to 2 and 4 μg/ml, respectively, were observed. We also evaluated the activity of oxadiazole ND-421 against other staphylococci and enterococci and in the presence of oxacillin for selected MRSA strains. The MIC for ND-421 is lowered severalfold in combination with oxacillin, as they synergize. The MIC90 of ND-421 against vancomycin-resistant enterococci is ≤1 μg/ml.

scholarly journals Resistance of Gram-Positive Bacteria to Current Antibacterial Agents and Overcoming Approaches

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2888 ◽  
Author(s):  
Buthaina Jubeh ◽  
Zeinab Breijyeh ◽  
Rafik Karaman
Keyword(s):  
Turning Point ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Gram Positive ◽  
Medical Interventions ◽  
Gram Positive Bacteria ◽  
New Antibiotics ◽  
Vancomycin Resistant ◽  
New Treatments ◽  
Emergence Of Resistance

The discovery of antibiotics has created a turning point in medical interventions to pathogenic infections, but unfortunately, each discovery was consistently followed by the emergence of resistance. The rise of multidrug-resistant bacteria has generated a great challenge to treat infections caused by bacteria with the available antibiotics. Today, research is active in finding new treatments for multidrug-resistant pathogens. In a step to guide the efforts, the WHO has published a list of the most dangerous bacteria that are resistant to current treatments and requires the development of new antibiotics for combating the resistance. Among the list are various Gram-positive bacteria that are responsible for serious healthcare and community-associated infections. Methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecium, and drug-resistant Streptococcus pneumoniae are of particular concern. The resistance of bacteria is an evolving phenomenon that arises from genetic mutations and/or acquired genomes. Thus, antimicrobial resistance demands continuous efforts to create strategies to combat this problem and optimize the use of antibiotics. This article aims to provide a review of the most critical resistant Gram-positive bacterial pathogens, their mechanisms of resistance, and the new treatments and approaches reported to circumvent this problem.

Redox-active cationic organoiron complex: a promising lead structure for developing antimicrobial agents with activity against Gram-positive pathogens including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium

RSC Advances ◽  
2015 ◽  
Vol 5 (105) ◽  
pp. 86421-86427 ◽  
Author(s):  
Alaa S. Abd-El-Aziz ◽  
Christian Agatemor ◽  
Nola Etkin ◽  
David P. Overy ◽  
Russell G. Kerr
Keyword(s):  
Antimicrobial Agents ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Multidrug Resistant ◽  
Gram Positive ◽  
Lead Structure ◽  
Gram Positive Bacteria ◽  
Redox Active ◽  
Vancomycin Resistant ◽  
Organoiron Complexes ◽  
Multidrug Resistant Strain

A redox-active, cationic organoiron complexes active against multidrug-resistant strain of Gram-positive bacteria is presented as a potential new lead structure for the design of antimicrobial agents.

scholarly journals Comparative Analysis of Antimicrobial Activities of Valinomycin and Cereulide, the Bacillus cereus Emetic Toxin

2011 ◽  
Vol 77 (8) ◽  
pp. 2755-2762 ◽  
Author(s):  
Marcel H. Tempelaars ◽  
Susana Rodrigues ◽  
Tjakko Abee
Keyword(s):  
Antimicrobial Activity ◽  
Comparative Analysis ◽  
Membrane Potential ◽  
Bacillus Cereus ◽  
Antimicrobial Activities ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Ph Range ◽  
Main Component

ABSTRACTCereulide and valinomycin are highly similar cyclic dodecadepsipeptides with potassium ionophoric properties. Cereulide, produced by members of theBacillus cereusgroup, is known mostly as emetic toxin, and no ecological function has been assigned. A comparative analysis of the antimicrobial activity of valinomycin produced byStreptomycesspp. and cereulide was performed at a pH range of pH 5.5 to pH 9.5, under anaerobic and aerobic conditions. Both compounds display pH-dependent activity against selected Gram-positive bacteria, includingStaphylococcus aureus,Listeria innocua,Listeria monocytogenes,Bacillus subtilis, andBacillus cereusATCC 10987. Notably,B. cereusstrain ATCC 14579 and the emeticB. cereusstrains F4810/72 and A529 showed reduced sensitivity to both compounds, with the latter two strains displaying full resistance to cereulide. Both compounds showed no activity against the selected Gram-negative bacteria. Antimicrobial activity against Gram-positive bacteria was highest at alkaline pH values, where the membrane potential (ΔΨ) is the main component of the proton motive force (PMF). Furthermore, inhibition of growth was observed in both aerobic and anaerobic conditions. Determination of the ΔΨ, using the membrane potential probe DiOC2(3) (in the presence of 50 mM KCl) in combination with flow cytometry, demonstrated for the first time the ability of cereulide to dissipate the ΔΨ in sensitive Gram-positive bacteria. The putative role of cereulide production in the ecology of emeticB. cereusis discussed.

scholarly journals In Vitro Activities of a New Ketolide, ABT-773, against Multidrug-Resistant Gram-Positive Cocci

2001 ◽  
Vol 45 (12) ◽  
pp. 3640-3643 ◽  
Author(s):  
Kavindra V. Singh ◽  
Kumthorn Malathum ◽  
Barbara E. Murray
Keyword(s):  
Staphylococcus Aureus ◽  
Enterococcus Faecium ◽  
Multidrug Resistant ◽  
Gram Positive ◽  
Methicillin Resistant ◽  
Gram Positive Bacteria ◽  
Vancomycin Resistant ◽  
Almost All ◽  
Gram Positive Cocci

ABSTRACT The in vitro activities of ABT-773 were evaluated against 324 strains of gram-positive bacteria, including multidrug-resistantStaphylococcus spp. and Enterococcus spp. ABT-773 had lower MIC ranges, MICs at which 50% of isolates are inhibited (MIC50s), and MIC90s than erythromycin or clindamycin for almost all isolates tested. The MICs of ABT-773 were also lower than those of quinupristin-dalfopristin (Q-D) for methicillin-susceptible Staphylococcus aureus,Rhodococcus spp., and Streptococcus spp., while the MICs of Q-D were lower than those of ABT-773 for methicillin-resistant S. aureus and Enterococcus faecium, including vancomycin-resistant isolates.

scholarly journals In Vitro Activities of Daptomycin, Vancomycin, Linezolid, and Quinupristin-Dalfopristin against Staphylococci and Enterococci, Including Vancomycin- Intermediate and -Resistant Strains

2000 ◽  
Vol 44 (4) ◽  
pp. 1062-1066 ◽  
Author(s):  
Michael J. Rybak ◽  
Ellie Hershberger ◽  
Tabitha Moldovan ◽  
Richard G. Grucz
Keyword(s):  
Multidrug Resistant ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Vancomycin Resistant Enterococci ◽  
Alternative Drug ◽  
Potential Alternative ◽  
Resistant Strains ◽  
Vancomycin Resistant ◽  
Time Kill

ABSTRACT The in vitro activity of daptomycin was compared with those of vancomycin, linezolid, and quinupristin-dalfopristin against a variety (n = 203) of gram-positive bacteria, including methicillin-resistant Staphylococcus aureus and S. epidermidis (MRSA and MRSE, respectively), vancomycin-resistant enterococci (VRE), and vancomycin-intermediate S. aureus(VISA). Overall, daptomycin was more active against all organisms tested, except Enterococcus faecium and VISA, against which its activity was similar to that of quinupristin-dalfopristin. In time-kill studies with MRSA, MRSE, VRE, and VISA, daptomycin demonstrated greater bactericidal activity than all other drugs tested, killing ≥3 log CFU/ml by 8 h. Daptomycin may be a potential alternative drug therapy for multidrug-resistant gram-positive organisms and warrants further investigation.

scholarly journals Pharmacodynamics of ClpP-Activating Antibiotic Combinations against Gram-Positive Pathogens

2019 ◽  
Vol 64 (1) ◽  
Author(s):  
Nader Mroue ◽  
Anu Arya ◽  
Autumn Brown Gandt ◽  
Cameron Russell ◽  
Angel Han ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
High Density ◽  
Infection Model ◽  
Drug Resistant ◽  
Gram Positive ◽  
Bacterial Killing ◽  
Resistance Development ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Vancomycin Resistant

ABSTRACT It is often difficult to cure endocarditis, osteomyelitis, and device-associated infections caused by Gram-positive pathogens, despite therapy with clinically appropriate antibiotics. This may be due to antibiotic tolerance or resistance development. Acyldepsipeptides (ADEPs) are a class of bactericidal compounds active against a variety of clinically important Gram-positive bacteria, including staphylococci, streptococci, and enterococci. ADEPs activate caseinolytic protease P (ClpP), killing high-density, nondividing cultures of bacteria that are tolerant to approved classes of antibiotics. Acyldepsipeptide analog 4 (ADEP4) was active against a panel of drug-resistant Gram-positive pathogens in MIC assays, with no preexisting resistance detected. Killing of stationary-phase cultures was observed when ADEP4 was combined with multiple classes of approved antibiotics. Additionally, a hollow-fiber infection model was used to assess the effects of ADEP4 antibiotic combinations on bacterial killing and resistance development. These studies were performed on high-density cultures of methicillin-resistant S. aureus (MRSA), methicillin-susceptible S. aureus (MSSA), and vancomycin-resistant Enterococcus faecalis (VRE). None of the approved antibiotics linezolid, ampicillin, and oxacillin tested alone had bactericidal activity under these conditions. ADEP4 initially caused killing, but regrowth of the culture was apparent within 96 h due to resistance. Combinations of ADEP4 with linezolid or oxacillin caused substantially improved killing of MRSA or MSSA cultures, respectively, and no regrowth due to resistance was observed. The combination of ADEP4 and ampicillin eradicated cultures of VRE to the limit of detection within 52 h. These data suggest that combining ClpP activators with traditional antibiotics may be a good strategy to treat complicated Gram-positive infections.

scholarly journals The Mechanism of Action of Ginkgolic Acid (15:1) against Gram-Positive Bacteria Involves Cross Talk with Iron Homeostasis

2022 ◽  
Author(s):  
Zewen Wen ◽  
Yuxi Zhao ◽  
Zhengyang Gong ◽  
Yuanyuan Tang ◽  
Yanpeng Xiong ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Natural Product ◽  
Iron Homeostasis ◽  
Multidrug Resistant ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Ginkgolic Acid ◽  
Wide Range ◽  
Novel Antibiotics

The increasing emergence of infectious diseases associated with multidrug-resistant Gram-positive pathogens has raised the urgent need to develop novel antibiotics. GA (15:1) is a natural product derived from Ginkgo biloba and possesses a wide range of bioactivities, including antimicrobial activity.

scholarly journals Antimicrobial Nodule-Specific Cysteine-Rich Peptides Induce Membrane Depolarization-Associated Changes in the Transcriptome of Sinorhizobium meliloti

2013 ◽  
Vol 79 (21) ◽  
pp. 6737-6746 ◽  
Author(s):  
Hilda Tiricz ◽  
Attila Szűcs ◽  
Attila Farkas ◽  
Bernadett Pap ◽  
Rui M. Lima ◽  
...  
Keyword(s):  
Stress Responses ◽  
Sinorhizobium Meliloti ◽  
Antimicrobial Agents ◽  
Cellular Functions ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Peptide Family ◽  
Wide Range ◽  
Natural Target

ABSTRACTLeguminous plants establish symbiosis with nitrogen-fixing alpha- and betaproteobacteria, collectively called rhizobia, which provide combined nitrogen to support plant growth. Members of the inverted repeat-lacking clade of legumes impose terminal differentiation on their endosymbiotic bacterium partners with the help of the nodule-specific cysteine-rich (NCR) peptide family composed of close to 600 members. Among the few tested NCR peptides, cationic ones had antirhizobial activity measured by reduction or elimination of the CFU and uptake of the membrane-impermeable dye propidium iodide. Here, the antimicrobial spectrum of two of these peptides, NCR247 and NCR335, was investigated, and their effect on the transcriptome of the natural targetSinorhizobium melilotiwas characterized. Both peptides were able to kill quickly a wide range of Gram-negative and Gram-positive bacteria; however, their spectra were only partially overlapping, and differences were found also in their efficacy on given strains, indicating that the actions of NCR247 and NCR335 might be similar though not identical. Treatment ofS. meliloticultures with either peptide resulted in a quick downregulation of genes involved in basic cellular functions, such as transcription-translation and energy production, as well as upregulation of genes involved in stress and oxidative stress responses and membrane transport. Similar changes provoked mainly in Gram-positive bacteria by antimicrobial agents were coupled with the destruction of membrane potential, indicating that it might also be a common step in the bactericidal actions of NCR247 and NCR335.

scholarly journals In Vitro and In Vivo Activities of DA-7867, a New Oxazolidinone, against Aerobic Gram-Positive Bacteria

2005 ◽  
Vol 49 (6) ◽  
pp. 2498-2500 ◽  
Author(s):  
Eun Jeong Yoon ◽  
Yeong Woo Jo ◽  
Sung Hak Choi ◽  
Tae Ho Lee ◽  
Jae Keol Rhee ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Streptococcus Pneumoniae ◽  
Gram Positive ◽  
Methicillin Resistant ◽  
Gram Positive Bacteria ◽  
Vancomycin Resistant Enterococci ◽  
Infection Models ◽  
Vancomycin Resistant

ABSTRACT In vitro and in vivo activities of DA-7867 were assessed against methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and penicillin-resistant Streptococcus pneumoniae. All isolates were inhibited by DA-7867 at ≤0.78 μg/ml, a four-times-lower concentration than that of inhibition by linezolid. For murine infection models, DA-7867 also exhibited greater efficacy than linezolid against all isolates tested.

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