scholarly journals Safety, Tolerability, Systemic Exposure, and Metabolism of CRS3123, a Methionyl-tRNA Synthetase Inhibitor Developed for Treatment of Clostridium difficile, in a Phase 1 Study

2017 ◽  
Vol 61 (8) ◽  
Author(s):  
Seema U. Nayak ◽  
J. McLeod Griffiss ◽  
Jeffrey Blumer ◽  
Mary Ann O'Riordan ◽  
Wesley Gray ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Adverse Events ◽  
Intestinal Flora ◽  
Systemic Exposure ◽  
Trna Synthetase ◽  
Health Concern ◽  
Pharmacokinetic Analysis ◽  
Content Type ◽  
Wide Range ◽  
Methionyl Trna Synthetase

ABSTRACT Clostridium difficile causes antibiotic-associated diarrhea and is a major public health concern. Current therapies disrupt the protective intestinal flora, do not reliably prevent recurrent infections, and will be decreasingly effective should less susceptible strains emerge. CRS3123 is an oral agent that inhibits bacterial methionyl-tRNA synthetase and has potent activity against C. difficile and aerobic Gram-positive bacteria but little activity against Gram-negative bacteria, including anaerobes. This first-in-human, double-blind, placebo-controlled, dose escalation study evaluated the safety and systemic exposure of CRS3123 after a single oral dose in healthy adults. Five cohorts of eight subjects each received CRS3123 or placebo in a 3:1 ratio. Doses for the respective active arms were 100 mg, 200 mg, 400 mg, 800 mg, and 1,200 mg. Blood and urine were collected for pharmacokinetic analysis. CRS3123 concentrations were measured with validated LC-MS/MS techniques. There were no serious adverse events or immediate allergic reactions during administration of CRS3123. In the CRS3123-treated groups, the most frequent adverse events were decreased hemoglobin, headache, and abnormal urine analysis; all adverse events in the active-treatment groups were mild to moderate, and their frequency did not increase with dose. Although CRS3123 systemic exposure increased at higher doses, the increase was less than dose proportional. The absorbed drug was glucuronidated at reactive amino groups on the molecule, which precluded accurate pharmacokinetic analysis of the parent drug. Overall, CRS3123 was well tolerated over this wide range of doses. This safety profile supports further investigation of CRS3123 as a treatment for C. difficile infections. (This study has been registered at ClinicalTrials.gov under identifier NCT01551004.)

scholarly journals A Putative Cro-Like Repressor Contributes to Arylomycin Resistance in Staphylococcus aureus

2015 ◽  
Vol 59 (6) ◽  
pp. 3066-3074 ◽  
Author(s):  
Arryn Craney ◽  
Floyd E. Romesberg
Keyword(s):  
Staphylococcus Aureus ◽  
Ex Vivo ◽  
Transcriptional Regulator ◽  
Signal Peptidase ◽  
Health Concern ◽  
Resistant Bacteria ◽  
Type I ◽  
Wall Teichoic Acid ◽  
Content Type ◽  
Wide Range

ABSTRACTAntibiotic-resistant bacteria are a significant public health concern and motivate efforts to develop new classes of antibiotics. One such class of antibiotics is the arylomycins, which target type I signal peptidase (SPase), the enzyme responsible for the release of secreted proteins from their N-terminal leader sequences. Despite the essentiality, conservation, and relative accessibility of SPase, the activity of the arylomycins is limited against some bacteria, including the important human pathogenStaphylococcus aureus. To understand the origins of the limited activity againstS. aureus, we characterized the susceptibility of a panel of strains to two arylomycin derivatives, arylomycin A-C16and its more potent analog arylomycin M131. We observed a wide range of susceptibilities to the two arylomycins and found that resistant strains were sensitized by cotreatment with tunicamycin, which inhibits the first step of wall teichoic acid synthesis. To further understand howS. aureusresponds to the arylomycins, we profiled the transcriptional response ofS. aureusNCTC 8325 to growth-inhibitory concentrations of arylomycin M131 and found that it upregulates the cell wall stress stimulon (CWSS) and an operon consisting of a putative transcriptional regulator and three hypothetical proteins. Interestingly, we found that mutations in the putative transcriptional regulator are correlated with resistance, and selection for resistanceex vivodemonstrated that mutations in this gene are sufficient for resistance. The results begin to elucidate howS. aureuscopes with secretion stress and how it evolves resistance to the inhibition of SPase.

scholarly journals Mutations Associated with Reduced Surotomycin Susceptibility in Clostridium difficile and Enterococcus Species

2015 ◽  
Vol 59 (7) ◽  
pp. 4139-4147 ◽  
Author(s):  
Hannah M. Adams ◽  
Xiang Li ◽  
Carmela Mascio ◽  
Laurent Chesnel ◽  
Kelli L. Palmer
Keyword(s):  
Clostridium Difficile ◽  
Sequence Data ◽  
Acyl Carrier Protein ◽  
Serial Passage ◽  
Restriction Endonuclease Analysis ◽  
Health Concern ◽  
Content Type ◽  
Cyclic Lipopeptide ◽  
Illumina Sequence

ABSTRACTClostridium difficileinfection (CDI) is an urgent public health concern causing considerable clinical and economic burdens. CDI can be treated with antibiotics, but recurrence of the disease following successful treatment of the initial episode often occurs. Surotomycin is a rapidly bactericidal cyclic lipopeptide antibiotic that is in clinical trials for CDI treatment and that has demonstrated superiority over vancomycin in preventing CDI relapse. Surotomycin is a structural analogue of the membrane-active antibiotic daptomycin. Previously, we utilizedin vitroserial passage experiments to deriveC. difficilestrains with reduced surotomycin susceptibilities. The parent strains used included ATCC 700057 and clinical isolates from the restriction endonuclease analysis (REA) groups BI and K. Serial passage experiments were also performed with vancomycin-resistant and vancomycin-susceptibleEnterococcus faeciumandEnterococcus faecalis. The goal of this study is to identify mutations associated with reduced surotomycin susceptibility inC. difficileand enterococci. Illumina sequence data generated for the parent strains and serial passage isolates were compared. We identified nonsynonymous mutations in genes coding for cardiolipin synthase inC. difficileATCC 700057, enoyl-(acyl carrier protein) reductase II (FabK) and cell division protein FtsH2 inC. difficileREA type BI, and a PadR family transcriptional regulator inC. difficileREA type K. Among the 4 enterococcal strain pairs, 20 mutations were identified, and those mutations overlap those associated with daptomycin resistance. These data give insight into the mechanism of action of surotomycin againstC. difficile, possible mechanisms for resistance emergence during clinical use, and the potential impacts of surotomycin therapy on intestinal enterococci.

scholarly journals A Nutrient-Regulated Cyclic Diguanylate Phosphodiesterase Controls Clostridium difficile Biofilm and Toxin Production during Stationary Phase

2017 ◽  
Vol 85 (9) ◽  
Author(s):  
Erin B. Purcell ◽  
Robert W. McKee ◽  
David S. Courson ◽  
Elizabeth M. Garrett ◽  
Shonna M. McBride ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Stationary Phase ◽  
Nutrient Availability ◽  
Biofilm Formation ◽  
Biochemical Characterization ◽  
Toxin Production ◽  
Physiological Adaptation ◽  
Cyclic Diguanylate ◽  
Content Type ◽  
Wide Range

ABSTRACT The signaling molecule cyclic diguanylate (c-di-GMP) mediates physiological adaptation to extracellular stimuli in a wide range of bacteria. The complex metabolic pathways governing c-di-GMP synthesis and degradation are highly regulated, but the specific cues that impact c-di-GMP signaling are largely unknown. In the intestinal pathogen Clostridium difficile, c-di-GMP inhibits flagellar motility and toxin production and promotes pilus-dependent biofilm formation, but no specific biological functions have been ascribed to any of the individual c-di-GMP synthases or phosphodiesterases (PDEs). Here, we report the functional and biochemical characterization of a c-di-GMP PDE, PdcA, 1 of 37 confirmed or putative c-di-GMP metabolism proteins in C. difficile 630. Our studies reveal that pdcA transcription is controlled by the nutrient-regulated transcriptional regulator CodY and accordingly increases during stationary phase. In addition, PdcA PDE activity is allosterically regulated by GTP, further linking c-di-GMP levels to nutrient availability. Mutation of pdcA increased biofilm formation and reduced toxin biosynthesis without affecting swimming motility or global intracellular c-di-GMP. Analysis of the transcriptional response to pdcA mutation indicates that PdcA-dependent phenotypes manifest during stationary phase, consistent with regulation by CodY. These results demonstrate that inactivation of this single PDE gene is sufficient to impact multiple c-di-GMP-dependent phenotypes, including the production of major virulence factors, and suggest a link between c-di-GMP signaling and nutrient availability.

scholarly journals Pharmacokinetics of LFF571 and Vancomycin in Patients with Moderate Clostridium difficile Infections

2014 ◽  
Vol 59 (3) ◽  
pp. 1441-1445 ◽  
Author(s):  
Suraj G. Bhansali ◽  
Kathleen Mullane ◽  
Lillian S. L. Ting ◽  
Jennifer A. Leeds ◽  
Kristina Dabovic ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Diarrheal Disease ◽  
Systemic Exposure ◽  
Serum Levels ◽  
Controlled Study ◽  
Content Type ◽  
Drug Concentrations ◽  
End Of Treatment ◽  
To Receive

ABSTRACTClostridium difficileinfection causes diarrheal disease with potentially fatal complications. Although treatments are available, including vancomycin, metronidazole, and fidaxomicin, the recurrence of disease after therapy remains a problem. LFF571 is a novel thiopeptide antibacterial that showsin vitropotency againstC. difficilethat is comparable to or greater than that of other clinically used antibiotics. Here, we compare the pharmacokinetics (PK) of LFF571 and vancomycin in patients withC. difficileinfection as part of an early efficacy study. This multicenter, randomized, evaluator-blind, and active-controlled study evaluated the safety, efficacy, and pharmacokinetics of LFF571 in adults with primary episodes or first relapses of moderateC. difficileinfections. Patients were randomized to receive 200 mg of LFF571 or 125 mg of vancomycin four times daily for 10 days. The PK parameters were calculated from drug concentrations measured in serum and fecal samples. The systemic exposure following oral administration of 200 mg of LFF571 four times per day for 10 days in patients withC. difficileinfection was limited. The highest LFF571 serum concentration observed was 41.7 ng/ml, whereas the levels in feces at the end of treatment were between 107 and 12,900 μg/g. In comparison, the peak vancomycin level observed in serum was considerably higher, at 2.73 μg/ml; the levels of vancomycin in feces were not measured. Similar to healthy volunteers, patients withC. difficileinfections exhibited high fecal concentrations and low serum levels of LFF571. These results are consistent with the retention of LFF571 in the lumen of the gastrointestinal tract. (This study has been registered at ClinicalTrials.gov under registration no. NCT01232595.)

scholarly journals Development of Methionyl-tRNA Synthetase Inhibitors as Antibiotics for Gram-Positive Bacterial Infections

2017 ◽  
Vol 61 (11) ◽  
Author(s):  
Omeed Faghih ◽  
Zhongsheng Zhang ◽  
Ranae M. Ranade ◽  
J. Robert Gillespie ◽  
Sharon A. Creason ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Bacterial Species ◽  
Bacterial Load ◽  
Trna Synthetase ◽  
Resistant Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Methionyl Trna Synthetase

ABSTRACT Antibiotic-resistant bacteria are widespread and pose a growing threat to human health. New antibiotics acting by novel mechanisms of action are needed to address this challenge. The bacterial methionyl-tRNA synthetase (MetRS) enzyme is essential for protein synthesis, and the type found in Gram-positive bacteria is substantially different from its counterpart found in the mammalian cytoplasm. Both previously published and new selective inhibitors were shown to be highly active against Gram-positive bacteria with MICs of ≤1.3 μg/ml against Staphylococcus, Enterococcus, and Streptococcus strains. Incorporation of radioactive precursors demonstrated that the mechanism of activity was due to the inhibition of protein synthesis. Little activity against Gram-negative bacteria was observed, consistent with the fact that Gram-negative bacterial species contain a different type of MetRS enzyme. The ratio of the MIC to the minimum bactericidal concentration (MBC) was consistent with a bacteriostatic mechanism. The level of protein binding of the compounds was high (>95%), and this translated to a substantial increase in MICs when the compounds were tested in the presence of serum. Despite this, the compounds were very active when they were tested in a Staphylococcus aureus murine thigh infection model. Compounds 1717 and 2144, given by oral gavage, resulted in 3- to 4-log decreases in the bacterial load compared to that in vehicle-treated mice, which was comparable to the results observed with the comparator drugs, vancomycin and linezolid. In summary, the research describes MetRS inhibitors with oral bioavailability that represent a class of compounds acting by a novel mechanism with excellent potential for clinical development.

scholarly journals Multiple-Ascending-Dose Phase 1 Clinical Study of the Safety, Tolerability, and Pharmacokinetics of CRS3123, a Narrow-Spectrum Agent with Minimal Disruption of Normal Gut Microbiota

2019 ◽  
Vol 64 (1) ◽  
Author(s):  
Barbara K. Lomeli ◽  
Hal Galbraith ◽  
Jared Schettler ◽  
George A. Saviolakis ◽  
Wael El-Amin ◽  
...  
Keyword(s):  
Adverse Events ◽  
Gut Microbiota ◽  
Phase 1 ◽  
Toxin Production ◽  
Trna Synthetase ◽  
Serious Adverse Events ◽  
Content Type ◽  
Clostridioides Difficile ◽  
Clinically Significant ◽  
Microbiome Data

ABSTRACT CRS3123 is a novel small molecule that potently inhibits methionyl-tRNA synthetase of Clostridioides difficile, inhibiting C. difficile toxin production and spore formation. CRS3123 has been evaluated in a multiple-ascending-dose placebo-controlled phase 1 trial. Thirty healthy subjects, ages 18 to 45 years, were randomized into three cohorts of 10 subjects each, receiving either 200, 400, or 600 mg of CRS3123 (8 subjects per cohort) or placebo (2 subjects per cohort) by oral administration twice daily for 10 days. CRS3123 was generally safe and well tolerated, with no serious adverse events (SAEs) or severe treatment-emergent adverse events (TEAEs) reported. All subjects completed their assigned treatment and follow-up visits, and there were no trends in systemic, vital sign, or laboratory TEAEs. There were no QTcF interval changes or any clinically significant changes in other electrocardiogram (ECG) intervals or morphology. CRS3123 showed limited but detectable systemic uptake; although absorption increased with increasing dose, the increase was less than dose proportional. Importantly, the bulk of the oral dose was not absorbed, and fecal concentrations were substantially above the MIC90 value of 1 μg/ml at all dosages tested. Subjects receiving either of the two lower doses of CRS3123 exhibited minimal disruption of normal gut microbiota after 10 days of twice-daily dosing. CRS3123 was inactive against important commensal anaerobes, including Bacteroides, bifidobacteria, and commensal clostridia. Microbiome data showed favorable differentiation compared to other CDI therapeutics. These results support further development of CRS3123 as an oral agent for the treatment of CDI. (This study has been registered at Clinicaltrials.gov under identifier NCT02106338.)

scholarly journals Inhibitors of Methionyl-tRNA Synthetase Have Potent Activity against Giardia intestinalis Trophozoites

2015 ◽  
Vol 59 (11) ◽  
pp. 7128-7131 ◽  
Author(s):  
Ranae M. Ranade ◽  
Zhongsheng Zhang ◽  
J. Robert Gillespie ◽  
Sayaka Shibata ◽  
Christophe L. M. J. Verlinde ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Trna Synthetase ◽  
Giardia Intestinalis ◽  
Content Type ◽  
Mammalian Cell Lines ◽  
Protozoan Pathogen ◽  
Low Cytotoxicity ◽  
Novel Drug ◽  
Methionyl Trna Synthetase ◽  
Further Development

ABSTRACTThe methionyl-tRNA synthetase (MetRS) is a novel drug target for the protozoan pathogenGiardia intestinalis. This protist contains a single MetRS that is distinct from the human cytoplasmic MetRS. A panel of MetRS inhibitors was tested against recombinantGiardiaMetRS,Giardiatrophozoites, and mammalian cell lines. The best compounds inhibited trophozoite growth at 500 nM (metronidazole did so at ∼5,000 nM) and had low cytotoxicity against mammalian cells, indicating excellent potential for further development as anti-Giardiadrugs.

scholarly journals ComparativeIn VitroActivities of SMT19969, a New Antimicrobial Agent, against Clostridium difficile and 350 Gram-Positive and Gram-Negative Aerobic and Anaerobic Intestinal Flora Isolates

2013 ◽  
Vol 57 (10) ◽  
pp. 4872-4876 ◽  
Author(s):  
Ellie J. C. Goldstein ◽  
Diane M. Citron ◽  
Kerin L. Tyrrell ◽  
C. Vreni Merriam
Keyword(s):  
Staphylococcus Aureus ◽  
Clostridium Difficile ◽  
Intestinal Flora ◽  
Colonization Resistance ◽  
Gram Positive ◽  
Gram Negative ◽  
Content Type ◽  
Aerobic And Anaerobic ◽  
Group Species

ABSTRACTThe comparativein vitroactivity of SMT19969, a novel, narrow-spectrum, nonabsorbable agent, was studied against 50 ribotype-definedClostridium difficilestrains, 174 Gram-positive and 136 Gram-negative intestinal anaerobes, and 40 Gram-positive aerobes. SMT19969 was one dilution more active againstC. difficileisolates (MIC range, 0.125 to 0.5 μg/ml; MIC90, 0.25 μg/ml), including ribotype 027 strains, than fidaxomicin (range, 0.06 to 1 μg/ml; MIC90, 0.5 μg/ml) and two to six dilutions lower than either vancomycin or metronidazole. SMT19969 and fidaxomicin were generally less active against Gram-negative anaerobes, especially theBacteroides fragilisgroup species, than vancomycin and metronidazole, suggesting that SMT19969 has a lesser impact on the normal intestinal microbiota that maintain colonization resistance. SMT19969 showed limited activity against other Gram-positive anaerobes, includingBifidobacteriaspecies,Eggerthella lenta,Finegoldia magna, andPeptostreptococcus anaerobius, with MIC90s of >512, >512, 64, and 64 μg/ml, respectively.Clostridiumspecies showed various levels of susceptibility, withC. innocuumbeing susceptible (MIC90, 1 μg/ml) andC. ramosumandC. perfringensbeing nonsusceptible (MIC90, >512 μg/ml). Activity againstLactobacillusspp. (range, 0.06 to >512 μg/ml; MIC90, >512 μg/ml) was comparable to that of fidaxomicin and varied by species and strain. Gram-positive aerobic cocci (Staphylococcus aureus,Enterococcus faecalis,E. faecium, and streptococci) showed high SMT19969 MIC90values (128 to >512 μg/ml).

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