scholarly journals Thiosemicarbazide Derivatives Decrease the ATPase Activity of Staphylococcus aureus Topoisomerase IV, Inhibit Mycobacterial Growth, and Affect Replication in Mycobacterium smegmatis

2021 ◽  
Vol 22 (8) ◽  
pp. 3881
Author(s):  
Aleksandra Kowalczyk ◽  
Agata Paneth ◽  
Damian Trojanowski ◽  
Piotr Paneth ◽  
Jolanta Zakrzewska-Czerwińska ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Atpase Activity ◽  
Mycobacterium Smegmatis ◽  
Time Lapse ◽  
In Vivo Studies ◽  
Bacterial Cells ◽  
Small Molecular Weight ◽  
Topoisomerase Iv ◽  
Replication Process

Compounds targeting bacterial topoisomerases are of interest for the development of antibacterial agents. Our previous studies culminated in the synthesis and characterization of small-molecular weight thiosemicarbazides as the initial prototypes of a novel class of gyrase and topoisomerase IV inhibitors. To expand these findings with further details on the mode of action of the most potent compounds, enzymatic studies combined with a molecular docking approach were carried out, the results of which are presented herein. The biochemical assay for 1-(indol-2-oyl)-4-(4-nitrophenyl) thiosemicarbazide (4) and 4-benzoyl-1-(indol-2-oyl) thiosemicarbazide (7), showing strong inhibitory activity against Staphylococcus aureus topoisomerase IV, confirmed that these compounds reduce the ability of the ParE subunit to hydrolyze ATP rather than act by stabilizing the cleavage complex. Compound 7 showed better antibacterial activity than compound 4 against clinical strains of S. aureus and representatives of the Mycobacterium genus. In vivo studies using time-lapse microfluidic microscopy, which allowed for the monitoring of fluorescently labelled replisomes, revealed that compound 7 caused an extension of the replication process duration in Mycobacterium smegmatis, as well as the growth arrest of bacterial cells. Despite some similarities to the mechanism of action of novobiocin, these compounds show additional, unique properties, and can thus be considered a novel group of inhibitors of the ATPase activity of bacterial type IIA topoisomerases.

scholarly journals Evaluation of a bone filler scaffold for local antibiotic delivery to prevent Staphylococcus aureus infection in a contaminated bone defect

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Karen E. Beenken ◽  
Mara J. Campbell ◽  
Aura M. Ramirez ◽  
Karrar Alghazali ◽  
Christopher M. Walker ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bone Defect ◽  
Rabbit Model ◽  
In Vivo Studies ◽  
Bovine Bone ◽  
Bone Filler ◽  
Antibiotic Release ◽  
Local Antibiotic ◽  
Antibiotic Delivery

AbstractWe previously reported the development of an osteogenic bone filler scaffold consisting of degradable polyurethane, hydroxyapatite, and decellularized bovine bone particles. The current study was aimed at evaluating the use of this scaffold as a means of local antibiotic delivery to prevent infection in a bone defect contaminated with Staphylococcus aureus. We evaluated two scaffold formulations with the same component ratios but differing overall porosity and surface area. Studies with vancomycin, daptomycin, and gentamicin confirmed that antibiotic uptake was concentration dependent and that increased porosity correlated with increased uptake and prolonged antibiotic release. We also demonstrate that vancomycin can be passively loaded into either formulation in sufficient concentration to prevent infection in a rabbit model of a contaminated segmental bone defect. Moreover, even in those few cases in which complete eradication was not achieved, the number of viable bacteria in the bone was significantly reduced by treatment and there was no radiographic evidence of osteomyelitis. Radiographs and microcomputed tomography (µCT) analysis from the in vivo studies also suggested that the addition of vancomycin did not have any significant effect on the scaffold itself. These results demonstrate the potential utility of our bone regeneration scaffold for local antibiotic delivery to prevent infection in contaminated bone defects.

Cefotaxime and amikacin: results of in vitro and in vivo studies against Gram-negative bacteria and Staphylococcus aureus

1980 ◽  
Vol 6 (suppl A) ◽  
pp. 55-61 ◽  
Author(s):  
J. Klastersky ◽  
H. Gaya ◽  
S. H. Zinner ◽  
C. Bernard ◽  
J-C. Ryff ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
In Vivo Studies ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
And Staphylococcus Aureus

scholarly journals Small-Colony Mutants of Staphylococcus aureus Allow Selection of Gyrase-Mediated Resistance to Dual-Target Fluoroquinolones

2002 ◽  
Vol 46 (8) ◽  
pp. 2498-2506 ◽  
Author(s):  
Xiao-Su Pan ◽  
Penelope J. Hamlyn ◽  
Raquel Talens-Visconti ◽  
Fabiana L. Alovero ◽  
Ruben H. Manzo ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Drug Target ◽  
Quinolone Resistance ◽  
Second Step ◽  
Resistant Bacteria ◽  
Topoisomerase Iv ◽  
Small Colony ◽  
Dual Target ◽  
Selection Of

ABSTRACT Fluoroquinolones acting equally through DNA gyrase and topoisomerase IV in vivo are considered desirable in requiring two target mutations for emergence of resistant bacteria. To investigate this idea, we have studied the response of Staphylococcus aureus RN4220 to stepwise challenge with sparfloxacin, a known dual-target agent, and with NSFQ-105, a more potent sulfanilyl fluoroquinolone that behaves similarly. First-step mutants were obtained with both drugs but only at the MIC. These mutants exhibited distinctive small-colony phenotypes and two- to fourfold increases in MICs of NSFQ-105, sparfloxacin, and ciprofloxacin. No changes were detected in the quinolone resistance-determining regions of the gyrA, gyrB, grlA, or grlB gene. Quinolone-induced small-colony mutants shared the delayed coagulase response but not the requirement for menadione, hemin, or thymidine characteristic of small-colony variants, a subpopulation of S. aureus that is often defective in electron transport. Second-step mutants selected with NSFQ-105 had gyrA(S84L) alterations; those obtained with sparfloxacin carried a gyrA(D83A) mutation or a novel gyrB deletion (ΔRKSAL, residues 405 to 409) affecting a trypsin-sensitive region linking functional domains of S. aureus GyrB. Each mutation was associated with four- to eightfold increases in MICs of NSFQ-105 and sparfloxacin, but not of ciprofloxacin, which we confirm targets topoisomerase IV. The presence of wild-type grlB-grlA gene sequences in second-step mutants excluded involvement of topoisomerase IV in the small-colony phenotype. Growth revertants retaining mutant gyrA or gyrB alleles were quinolone susceptible, indicating that resistance to NSFQ-105 and sparfloxacin was contingent on the small-colony mutation. We propose that small-colony mutations unbalance target sensitivities, perhaps through altered ATP or topoisomerase levels, such that gyrase becomes the primary drug target. Breaking of target parity by genetic or physiological means eliminates the need for two target mutations and provides a novel mechanism for stepwise selection of quinolone resistance.

scholarly journals 204. Antagonistic Effect of Colistin on Vancomycin Activity Against Methicillin-Resistant Staphylococcus aureus in in vitro and in vivo Studies

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S120-S121
Author(s):  
Sungim Choi ◽  
Taeeun Kim ◽  
Seongman Bae ◽  
Eunmi Yang ◽  
Su-Jin Park ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Antagonistic Effect ◽  
In Vivo Studies ◽  
Infection Model ◽  
Methicillin Resistant ◽  
Checkerboard Assay ◽  
Mrsa Strains ◽  
Time Kill

Abstract Background There is a concern that the vancomycin MIC of methicillin-resistant Staphylococcus aureus (MRSA) could be increased by concomitant colistin administered against multidrug-resistant gram-negative pathogen. Methods We confirmed the molecular genotypes of MRSA blood isolates collected in a tertiary hospital in Seoul, South Korea, and selected representative strains from the community-associated MRSA strains (CA-MRSA, ST72-SCCmec IV) and hospital-acquired MRSA strains (HA-MRSA, ST5-SCCmec II). USA CA-MRSA (USA300, ST8-SCCmec IV) and MRSA standard strain (ATCC 43300, ST39-SCCmec II) were also used for comparison with representative. We identified changes of the vancomycin MIC in MRSA by colistin exposure in a checkerboard assay and performed a time-kill assay to evaluate the combined effect of vancomycin and colistin on MRSA. In addition, we administered vancomycin, colistin, and combination of two antibiotics, respectively, to a neutropenic murine thigh infection model to evaluate the in vivo antagonistic effect of colistin on vancomycin treatment. Results In the checkerboard assay, all 4 MRSA strains showed a tendency for the vancomycin MIC to increase along with increasing concentrations of colistin. However, the time-kill assay showed the antagonism of vancomycin and colistin only against ST5-MRSA, when vancomycin concentration was 2 times the vancomycin MIC (Figure 1). No antagonism was observed in other strains. In the murine thigh infection model of ST5-MRSA, vancomycin monotherapy showed a significant log CFU reduction compared with a combination of vancomycin and colistin at 24 hours, demonstrating the antagonistic effect of vancomycin and colistin combination (Figure 2). Conclusion This study showed that exposure of colistin to certain MRSA strains may reduce the susceptibility to vancomycin. Combination therapy with vancomycin and colistin for MDR pathogens infections might result in treatment failure for concurrent MRSA infection. Disclosures All authors: No reported disclosures.

scholarly journals The purine biosynthesis regulator PurR moonlights as a virulence regulator in Staphylococcus aureus

2019 ◽  
Vol 116 (27) ◽  
pp. 13563-13572 ◽  
Author(s):  
William E. Sause ◽  
Divya Balasubramanian ◽  
Irnov Irnov ◽  
Richard Copin ◽  
Mitchell J. Sullivan ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factors ◽  
Ex Vivo ◽  
Purine Biosynthesis ◽  
In Vivo Studies ◽  
Human Neutrophils ◽  
Infection Models ◽  
Genes Encoding ◽  
Virulence Regulator

The pathogen Staphylococcus aureus colonizes and infects a variety of different sites within the human body. To adapt to these different environments, S. aureus relies on a complex and finely tuned regulatory network. While some of these networks have been well-elucidated, the functions of more than 50% of the transcriptional regulators in S. aureus remain unexplored. Here, we assess the contribution of the LacI family of metabolic regulators to staphylococcal virulence. We found that inactivating the purine biosynthesis regulator purR resulted in a strain that was acutely virulent in bloodstream infection models in mice and in ex vivo models using primary human neutrophils. Remarkably, these enhanced pathogenic traits are independent of purine biosynthesis, as the purR mutant was still highly virulent in the presence of mutations that disrupt PurR’s canonical role. Through the use of transcriptomics coupled with proteomics, we revealed that a number of virulence factors are differentially regulated in the absence of purR. Indeed, we demonstrate that PurR directly binds to the promoters of genes encoding virulence factors and to master regulators of virulence. These results guided us into further ex vivo and in vivo studies, where we discovered that S. aureus toxins drive the death of human phagocytes and mice, whereas the surface adhesin FnbA contributes to the increased bacterial burden observed in the purR mutant. Thus, S. aureus repurposes a metabolic regulator to directly control the expression of virulence factors, and by doing so, tempers its pathogenesis.

scholarly journals Enhancement of Fluoroquinolone Activity by C-8 Halogen and Methoxy Moieties: Action against a Gyrase Resistance Mutant of Mycobacterium smegmatis and a Gyrase-Topoisomerase IV Double Mutant of Staphylococcus aureus

2001 ◽  
Vol 45 (10) ◽  
pp. 2703-2709 ◽  
Author(s):  
Tao Lu ◽  
Xilin Zhao ◽  
Xinying Li ◽  
Alex Drlica-Wagner ◽  
Jian-Ying Wang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Mycobacterium Smegmatis ◽  
Double Mutant ◽  
Structure Refinement ◽  
Fluoroquinolone Resistance ◽  
Wild Type ◽  
Topoisomerase Iv ◽  
Methoxy Groups ◽  
Bactericidal Activities ◽  
Mutant Cells

ABSTRACT The increasing prevalence of antibiotic resistance among bacterial pathogens prompted a microbiological study of fluoroquinolone structure-activity relationships with resistant mutants. Bacteriostatic and bactericidal activities for 12 fluoroquinolones were examined with a gyrase mutant of Mycobacterium smegmatis and a gyrase-topoisomerase IV double mutant of Staphylococcus aureus. For both organisms C-8 halogen and C-8 methoxy groups enhanced activity. The MIC at which 99% of the isolates tested were inhibited (MIC99) was reduced three- to fivefold for the M. smegmatis mutant and seven- to eightfold for theS. aureus mutant by C-8 bromine, chlorine, and methoxy groups. With both organisms a smaller reduction in the MIC99 (two- to threefold) was associated with a C-8 fluorine moiety. In most comparisons with M. smegmatis the response to a C-8 substituent was similar (within twofold) for wild-type and mutant cells. In contrast, mutant S. aureuswas affected more than the wild type by the addition of a C-8 substituent. C-8 halogen and methoxy groups also improved the ability to kill the two mutants and the respective wild-type cells when measured with various fluoroquinolone concentrations during an incubation period equivalent to four to five doubling times. Collectively these data help define a group of fluoroquinolones that can serve (i) as a base for structure refinement and (ii) as test compounds for slowing the development of fluoroquinolone resistance during infection of vertebrate hosts.

scholarly journals EFFECT OF VIRGIN COCONUT OIL ON MYCOBACTERIUM SMEGMATIS AND STAPHYLOCOCCUS AUREUS TREATED WITH EXTRACTS OF ZANTHOXYLUM ACANTHOPODIUM FRUIT

2021 ◽  
pp. 114-117
Author(s):  
HEDDY JULISTIONO ◽  
INTAN PERMATASARI SUSENO ◽  
NURUL HANDAYANI ◽  
RINI HANDAYANI ◽  
PUSPA DEWI LOTULUNG
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Mycobacterium Smegmatis ◽  
Coconut Oil ◽  
Assay Method ◽  
Bacterial Cells ◽  
Virgin Coconut Oil ◽  
Herbal Formulation ◽  
Hexane Extracts ◽  
And Staphylococcus Aureus

Objectives: To understand the potency of herbal formulation of virgin coconut oil (VCO) and andaliman (Zanthoxylum acanthopodium) fruit activity against microbes, effects of ethylene acetate and hexane extracts of fruit of andaliman on viability and ions leakages of Mycobacterium smegmatis dan Staphylococcus aureus treated with VCO has been investigated. Methods: Antibacterial activity of extracts of andaliman fruit, or VCO, or andaliman and VCO against M. smegmatis and S. aureus was investigated using MTT assay method. Membrane disruption of bacterial cells treated with the plant extract and VCO was determined by measuring potassium and sodium ions leakages using Atomic Adsorbtion Spectrophotometer. Results: VCO of 512 μg/ml did not have antibacterial activity. In M. smegmatis treated with andaliman hexane extract, presence VCO decreased both ions leakage whereas in S. aureus treated with ethyl acetate extract only sodium ion was decreased. In both microorganisms, VCO could not protect cells of both M. smegmatis and S. aureus from death caused by andaliman extracts. Conclusions: VCO prevented ions leakages of the bacteria treated with extract of andaliman but did not protects cells from death.

Pharmacology and Safety of SB-497115-GR, an Orally Active Small Molecular Weight TPO Receptor Agonist, in Chimpanzees, Rats and Dogs.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2063-2063 ◽  
Author(s):  
Teresa Sellers ◽  
Timothy Hart ◽  
Michael Semanik ◽  
Krishna Murthy
Keyword(s):  
Molecular Weight ◽  
Clinical Trials ◽  
Receptor Agonist ◽  
Fold Increase ◽  
Distinct Species ◽  
In Vivo Studies ◽  
Small Molecular Weight ◽  
Platelet Counts

Abstract SB 497115-GR is a small molecular weight Tpo receptor (TpoR) agonist that has properties similar to thrombopoietin (TPO), primarily inducing proliferation and differentiation of megakaryocytes from bone marrow progenitor cells. SB-497115-GR is being developed for the treatment of thrombocytopenias, such as immune thrombocytopenic purpura. In vitro and in vivo studies have demonstrated that SB-497115-GR has very distinct species specificity. SB-497115 or other molecules in this class induced dose dependent STAT activation in platelets from humans and chimpanzees but not in platelets from laboratory animal species commonly used in drug safety studies. In order to demonstrate in vivo activity of SB-497115-GR, a single dose and 5 daily dose pharmacology and safety study in chimpanzees was conducted. To support initiation of clinical trials, a comprehensive package of toxicology studies was conducted including studies up to 14 days duration in rats and dogs. All procedures involving the care and use of animals in these studies were reviewed and approved by the appropriate Institutional Animal Care and Use Committees. Female chimpanzees (1–3/group) were administered vehicle or SB-497115-GR at doses of 0.1 to 10 mg/kg/day by oral gavage. For toxicology studies, SB-497115-GR was administered orally to rats (10/sex/group) by gavage at doses of 3 to 40 mg/kg/day and to dogs (3/sex/group) by capsule at doses of 3 to 30 mg/kg/day for 14 days. SB-497115-GR was well tolerated in chimpanzees, rats and dogs at all doses tested. In chimpanzees, no treatment related increases in platelet counts were observed after administration of single doses of up to 10 mg/kg or 5 daily doses of up to 3 mg/kg/day. However, following 5 daily doses of 10 mg/kg/day SB-497115-GR, there was a 1.3- to 2.4-fold increase in circulating platelet counts in 3 chimpanzees. A similar change in reticulated platelet counts was observed preceding this increase. In contrast, there was no effect of treatment for up to 14 days on platelet counts in rats or dogs. In conclusion, SB-497115-GR, an orally bioavailable small molecular weight agonist of the TpoR, has been shown to increase platelet counts in chimpanzees. These in vivo data confirm the in vitro data demonstrating the unique species-specific effects of this novel Tpo receptor agonist on platelets and were predictive of a pharmacodynamic effect currently being observed in human clinical trials.

IN VIVO STUDIES ON ANTISTAPHYLOCOCCAL PENICILLINASE SERUM

1964 ◽  
Vol 10 (4) ◽  
pp. 507-512
Author(s):  
M. Goldner ◽  
R. J. Wilson
Keyword(s):  
Staphylococcus Aureus ◽  
Combined Treatment ◽  
Rabbit Antiserum ◽  
Staphylococcal Infection ◽  
In Vivo Studies ◽  
Laboratory Animals ◽  
Single Strain ◽  
Lethal Doses ◽  
Observation Period

Several workers have shown that laboratory animals are protected from penicillin-resistant Staphylococcus aureus infections by antiserum to Bacillus cereus penicillinase in conjunction with benzylpenicillin. This paper shows that antiserum to staphylococcal penicillinase has the same effect. Concentrated penicillinase from a single strain of staphylococcus was used to prepare a rabbit antiserum. Groups of rabbits were injected intravenously with lethal doses of the same strain of staphylococcus. They were either given no treatment or were treated with penicillin only, antiserum only, or combined penicillin and antiserum. Antiserum was given in a single dose or in multiple doses. Throughout the 3-week observation period, the mortality in the group of rabbits receiving combined treatment was significantly less than in any other group. It was concluded that it might be possible to use antistaphylococcal penicillinase serum in the treatment of penicillin-resistant staphylococcal infection.

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