scholarly journals In VitroandIn VivoCharacterization of CB-183,315, a Novel Lipopeptide Antibiotic for Treatment of Clostridium difficile

2012 ◽  
Vol 56 (10) ◽  
pp. 5023-5030 ◽  
Author(s):  
Carmela T. M. Mascio ◽  
Lawrence I. Mortin ◽  
Karen T. Howland ◽  
Andrew D. G. Van Praagh ◽  
Shuxin Zhang ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Limit Of Detection ◽  
Disease Onset ◽  
Serial Passage ◽  
Postantibiotic Effect ◽  
Hamster Model ◽  
Content Type ◽  
Lipopeptide Antibiotic ◽  
Time Kill

ABSTRACTCB-183,315 is a novel lipopeptide antibiotic structurally related to daptomycin currently in phase 3 clinical development forClostridium difficile-associated diarrhea (CDAD). We report here thein vitromechanism of action, spontaneous resistance incidence, resistance by serial passage, time-kill kinetics, postantibiotic effect, and efficacy of CB-183,315 in a hamster model of lethal infection.In vitrodata showed that CB-183,315 dissipated the membrane potential ofStaphylococcus aureuswithout inducing changes in membrane permeability to small molecules. The rate of spontaneous resistance to CB-183,315 at 8× the MIC was below the limit of detection inC. difficile. Under selective pressure by serial passage with CB-183,315 againstC. difficile, the susceptibility of the bacteria changed no more than 2-fold during 15 days of serial passages. At 16× the MIC, CB-183,315 produced a ≥3-log reduction ofC. difficilein the time-kill assay. The postantibiotic effect of CB-183,315 at 8× the MIC was 0.9 h. At 80× the MIC the postantibiotic effect was more than 6 h. In the hamster model of CDAD, CB-183,315 and vancomycin both demonstrated potent efficacy in resolving initial disease onset, even at very low doses. After the conclusion of dosing, CB-183,315 and vancomycin showed a similar dose- and time-dependent pattern with respect to rates of CDAD recurrence.

scholarly journals In VitroandIn VivoActivities of the Novel Ketolide RBx 14255 against Clostridium difficile

2012 ◽  
Vol 56 (11) ◽  
pp. 5986-5989 ◽  
Author(s):  
Manoj Kumar ◽  
Tarun Mathur ◽  
Tarani K. Barman ◽  
G. Ramkumar ◽  
Ashish Bhati ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Time Dependent ◽  
Kinetics Study ◽  
The Novel ◽  
Promising Candidate ◽  
Hamster Model ◽  
Bacterial Killing ◽  
Content Type ◽  
Time Kill

ABSTRACTThe MIC90of RBx 14255, a novel ketolide, againstClostridium difficilewas 4 μg/ml (MIC range, 0.125 to 8 μg/ml), and this drug was found to be more potent than comparator drugs. Anin vitrotime-kill kinetics study of RBx 14255 showed time-dependent bacterial killing forC. difficile. Furthermore, in the hamster model ofC. difficileinfection, RBx 14255 demonstrated greater efficacy than metronidazole and vancomycin, making it a promising candidate forC. difficiletreatment.

scholarly journals MBX-500, a Hybrid Antibiotic withIn VitroandIn VivoEfficacy against Toxigenic Clostridium difficile

2012 ◽  
Vol 56 (9) ◽  
pp. 4786-4792 ◽  
Author(s):  
Michelle M. Butler ◽  
Dean L. Shinabarger ◽  
Diane M. Citron ◽  
Ciarán P. Kelly ◽  
Sofya Dvoskin ◽  
...  
Keyword(s):  
Weight Gain ◽  
Clostridium Difficile ◽  
Severe Disease ◽  
Normal Weight ◽  
New Drugs ◽  
Hamster Model ◽  
Resistance Development ◽  
Content Type

ABSTRACTClostridium difficileinfection (CDI) causes moderate to severe disease, resulting in diarrhea and pseudomembranous colitis. CDI is difficult to treat due to production of inflammation-inducing toxins, resistance development, and high probability of recurrence. Only two antibiotics are approved for the treatment of CDI, and the pipeline for therapeutic agents contains few new drugs. MBX-500 is a hybrid antibacterial, composed of an anilinouracil DNA polymerase inhibitor linked to a fluoroquinolone DNA gyrase/topoisomerase inhibitor, with potential as a new therapeutic for CDI treatment. Since MBX-500 inhibits three bacterial targets, it has been previously shown to be minimally susceptible to resistance development. In the present study, thein vitroandin vivoefficacies of MBX-500 were explored against the Gram-positive anaerobe,C. difficile. MBX-500 displayed potency across nearly 50 isolates, including those of the fluoroquinolone-resistant, toxin-overproducing NAP1/027 ribotype, performing as well as comparator antibiotics vancomycin and metronidazole. Furthermore, MBX-500 was a narrow-spectrum agent, displaying poor activity against many other gut anaerobes. MBX-500 was active in acute and recurrent infections in a toxigenic hamster model of CDI, exhibiting full protection against acute infections and prevention of recurrence in 70% of the animals. Hamsters treated with MBX-500 displayed significantly greater weight gain than did those treated with vancomycin. Finally, MBX-500 was efficacious in a murine model of CDI, again demonstrating a fully protective effect and permitting near-normal weight gain in the treated animals. These selective anti-CDI features support the further development of MBX 500 for the treatment of CDI.

scholarly journals Antistaphylococcal Activity of TD-1792, a Multivalent Glycopeptide-Cephalosporin Antibiotic

2011 ◽  
Vol 56 (3) ◽  
pp. 1584-1587 ◽  
Author(s):  
Johanne Blais ◽  
Stacey R. Lewis ◽  
Kevin M. Krause ◽  
Bret M. Benton
Keyword(s):  
Staphylococcus Aureus ◽  
Multidrug Resistant ◽  
Postantibiotic Effect ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Highly Active ◽  
Antistaphylococcal Activity ◽  
Cephalosporin Antibiotic ◽  
Time Kill

ABSTRACTTD-1792 is a new multivalent glycopeptide-cephalosporin antibiotic with potent activity against Gram-positive bacteria. Thein vitroactivity of TD-1792 was tested against 527Staphylococcus aureusisolates, including multidrug-resistant isolates. TD-1792 was highly active against methicillin-susceptibleS. aureus(MIC90, 0.015 μg/ml), methicillin-resistantS. aureus, and heterogeneous vancomycin-intermediateS. aureus(MIC90, 0.03 μg/ml). Time-kill studies demonstrated the potent bactericidal activity of TD-1792 at concentrations of ≤0.12 μg/ml. A postantibiotic effect of >2 h was observed after exposure to TD-1792.

scholarly journals The HtrA-Like Protease CD3284 Modulates Virulence of Clostridium difficile

2014 ◽  
Vol 82 (10) ◽  
pp. 4222-4232 ◽  
Author(s):  
Dennis Bakker ◽  
Anthony M. Buckley ◽  
Anne de Jong ◽  
Vincent J. C. van Winden ◽  
Joost P. A. Verhoeks ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Virulence Factors ◽  
Pathogenic Bacteria ◽  
Microarray Data Analysis ◽  
Toxin A ◽  
Hamster Model ◽  
Golden Syrian Hamster ◽  
Content Type

ABSTRACTIn the past decade,Clostridium difficilehas emerged as an important gut pathogen. Symptoms ofC. difficileinfection range from mild diarrhea to pseudomembranous colitis. Besides the two main virulence factors toxin A and toxin B, other virulence factors are likely to play a role in the pathogenesis of the disease. In other Gram-positive and Gram-negative pathogenic bacteria, conserved high-temperature requirement A (HtrA)-like proteases have been shown to have a role in protein homeostasis and quality control. This affects the functionality of virulence factors and the resistance of bacteria to (host-induced) environmental stresses. We found that theC. difficile630 genome encodes a single HtrA-like protease (CD3284; HtrA) and have analyzed its rolein vivoandin vitrothrough the creation of an isogenic ClosTron-basedhtrAmutant ofC. difficilestrain 630Δerm(wild type). In contrast to the attenuated phenotype seen withhtrAdeletion in other pathogens, this mutant showed enhanced virulence in the Golden Syrian hamster model of acuteC. difficileinfection. Microarray data analysis showed a pleiotropic effect ofhtrAon the transcriptome ofC. difficile, including upregulation of the toxin A gene. In addition,the htrAmutant showed reduced spore formation and adherence to colonic cells. Together, our data show thathtrAcan modulate virulence inC. difficile.

scholarly journals Surotomycin Demonstrates LowIn VitroFrequency of Resistance and Rapid Bactericidal Activity in Clostridium difficile, Enterococcus faecalis, and Enterococcus faecium

2014 ◽  
Vol 58 (7) ◽  
pp. 3976-3982 ◽  
Author(s):  
Carmela T. M. Mascio ◽  
Laurent Chesnel ◽  
Grace Thorne ◽  
Jared A. Silverman
Keyword(s):  
Clostridium Difficile ◽  
Enterococcus Faecalis ◽  
Bactericidal Activity ◽  
Enterococcus Faecium ◽  
Limit Of Detection ◽  
Serial Passage ◽  
Cross Resistance ◽  
Content Type ◽  
Naive Control ◽  
Emergence Of Resistance

ABSTRACTSurotomycin (CB-183,315) is an orally administered, minimally absorbed, selective bactericidal cyclic lipopeptide in phase 3 development for the treatment ofClostridium difficile-associated diarrhea. The aim of this study was to evaluate the emergence of resistance inC. difficile(ATCC 700057 and three recent clinical isolates from the restriction endonuclease analysis groups BI, BK, and K), vancomycin-susceptible (VS)Enterococcus faecalis(ATCC 49452), vancomycin-resistant (VR)E. faecalis(ATCC 700802), VSEnterococcus faecium(ATCC 6569), and VRE. faecium(ATCC 51559) under anaerobic conditions. The rate of spontaneous resistance was below the limit of detection (<10−8to <10−9) for surotomycin at 16 and 32× the MIC for all isolates tested. Under selective pressure by serial passage,C. difficilegrew in a maximum of 4 μg/ml surotomycin (final MICs of 2 to 8 μg/ml [4- to 16-fold higher than those of the naive control]) at day 15, with the exception of theC. difficileBK strain, which grew in 16 to 32 μg/ml (final MICs of 8 to 32 μg/ml [16- to 64-fold higher than those of the naive control]). Enterococci remained relatively unchanged over 15 days, growing in a maximum of 8 μg/ml surotomycin (final MICs of 2 to 16 μg/ml [8- to 64-fold higher than those of the naive control]). Of the isolates tested, no cross-resistance to vancomycin, rifampin, ampicillin, metronidazole, or moxifloxacin was observed. Surotomycin at 20× MIC demonstrated equally rapid bactericidal activity (≥3-log-unit reduction in CFU/ml in ≤8 h) against naive and reduced-susceptibility isolates ofC. difficile, VSEnterococcus(VSE), and VREnterococcus(VRE), except forC. difficileBK (2.6-log-unit reductions for both). These results suggest that emergence of resistance to surotomycin againstC. difficile,E. faecalis, andE. faeciumis likely to be rare.

scholarly journals Bacteriophage Combinations Significantly Reduce Clostridium difficile GrowthIn Vitroand ProliferationIn Vivo

2015 ◽  
Vol 60 (2) ◽  
pp. 968-981 ◽  
Author(s):  
Janet Y. Nale ◽  
Janice Spencer ◽  
Katherine R. Hargreaves ◽  
Anthony M. Buckley ◽  
Przemysław Trzepiński ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Oral Delivery ◽  
Therapeutic Potential ◽  
Bacterial Load ◽  
Range Analysis ◽  
Hamster Model ◽  
Content Type ◽  
Phage Types ◽  
Specific Phage

ABSTRACTThe microbiome dysbiosis caused by antibiotic treatment has been associated with both susceptibility to and relapse ofClostridium difficileinfection (CDI). Bacteriophage (phage) therapy offers target specificity and dose amplificationin situ, but few studies have focused on its use in CDI treatment. This mainly reflects the lack of strictly virulent phages that target this pathogen. While it is widely accepted that temperate phages are unsuitable for therapeutic purposes due to their transduction potential, analysis of sevenC. difficilephages confirmed that this impact could be curtailed by the application of multiple phage types. Here, host range analysis of six myoviruses and one siphovirus was conducted on 80 strains representing 21 major epidemic and clinically severe ribotypes. The phages had complementary coverage, lysing 18 and 62 of the ribotypes and strains tested, respectively. Single-phage treatments of ribotype 076, 014/020, and 027 strains showed an initial reduction in the bacterial load followed by the emergence of phage-resistant colonies. However, these colonies remained susceptible to infection with an unrelated phage. In contrast, specific phage combinations caused the complete lysis ofC. difficilein vitroand prevented the appearance of resistant/lysogenic clones. Using a hamster model, the oral delivery of optimized phage combinations resulted in reducedC. difficilecolonization at 36 h postinfection. Interestingly, free phages were recovered from the bowel at this time. In a challenge model of the disease, phage treatment delayed the onset of symptoms by 33 h compared to the time of onset of symptoms in untreated animals. These data demonstrate the therapeutic potential of phage combinations to treat CDI.

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 The Phosphotransfer Protein CD1492 Represses Sporulation Initiation in Clostridium difficile

2016 ◽  
Vol 84 (12) ◽  
pp. 3434-3444 ◽  
Author(s):  
Kevin O. Childress ◽  
Adrianne N. Edwards ◽  
Kathryn L. Nawrocki ◽  
Sarah E. Anderson ◽  
Emily C. Woods ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Clostridium Difficile ◽  
Molecular Mechanisms ◽  
Toxin Production ◽  
Negative Regulator ◽  
Hamster Model ◽  
Content Type ◽  
Sporulation Initiation

The formation of spores is critical for the survival ofClostridium difficileoutside the host gastrointestinal tract. Persistence ofC. difficilespores greatly contributes to the spread ofC. difficileinfection (CDI), and the resistance of spores to antimicrobials facilitates the relapse of infection. Despite the importance of sporulation toC. difficilepathogenesis, the molecular mechanisms controlling spore formation are not well understood. The initiation of sporulation is known to be regulated through activation of the conserved transcription factor Spo0A. Multiple regulators influence Spo0A activation in other species; however, many of these factors are not conserved inC. difficileand few novel factors have been identified. Here, we investigated the function of a protein, CD1492, that is annotated as a kinase and was originally proposed to promote sporulation by directly phosphorylating Spo0A. We found that deletion ofCD1492resulted in increased sporulation, indicating that CD1492 is a negative regulator of sporulation. Accordingly, we observed increased transcription of Spo0A-dependent genes in theCD1492mutant. Deletion of CD1492 also resulted in decreased toxin productionin vitroand in decreased virulence in the hamster model of CDI. Further, theCD1492mutant demonstrated effects on gene expression that are not associated with Spo0A activation, including lowersigDandrstAtranscription, suggesting that this protein interacts with factors other than Spo0A. Altogether, the data indicate that CD1492 negatively affects sporulation and positively influences motility and virulence. These results provide further evidence thatC. difficilesporulation is regulated differently from that of other endospore-forming species.

scholarly journals A Mixture of Functionally Oligoclonal Humanized Monoclonal Antibodies That Neutralize Clostridium difficile TcdA and TcdB with High Levels ofIn VitroPotency ShowsIn VivoProtection in a Hamster Infection Model

2013 ◽  
Vol 20 (3) ◽  
pp. 377-390 ◽  
Author(s):  
Nicola L. Davies ◽  
Joanne E. Compson ◽  
Brendon MacKenzie ◽  
Victoria L. O'Dowd ◽  
Amanda K. F. Oxbrow ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Clostridium Difficile ◽  
Neutralizing Antibodies ◽  
Disease Process ◽  
Care Facility ◽  
Infection Model ◽  
Hamster Model ◽  
Content Type ◽  
Toxin Binding

ABSTRACTClostridium difficileinfections are a major cause of antibiotic-associated diarrhea in hospital and care facility patients. In spite of the availability of effective antibiotic treatments,C. difficileinfection (CDI) is still a major cause of patient suffering, death, and substantial health care costs.Clostridium difficileexerts its major pathological effects through the actions of two protein exotoxins, TcdA and TcdB, which bind to and disrupt gut tissue. Antibiotics target the infecting bacteria but not the exotoxins. Administering neutralizing antibodies against TcdA and TcdB to patients receiving antibiotic treatment might modulate the effects of the exotoxins directly. We have developed a mixture of three humanized IgG1 monoclonal antibodies (MAbs) which neutralize TcdA and TcdB to address three clinical needs: reduction of the severity and duration of diarrhea, reduction of death rates, and reduction of the rate of recurrence. The UCB MAb mixture showed higher potency in a variety ofin vitrobinding and neutralization assays (∼10-fold improvements), higher levels of protection in a hamster model of CDI (82% versus 18% at 28 days), and higher valencies of toxin binding (12 versus 2 for TcdA and 3 versus 2 for TcdB) than other agents in clinical development. Comparisons of the MAb properties also offered some insight into the potential relative importance of TcdA and TcdB in the disease process.

scholarly journals Novel Polymyxin Combination with the Antiretroviral Zidovudine Exerts Synergistic Killing against NDM-Producing Multidrug-ResistantKlebsiella pneumoniae

2019 ◽  
Vol 63 (4) ◽  
Author(s):  
Yu-Wei Lin ◽  
Nusaibah Abdul Rahim ◽  
Jinxin Zhao ◽  
Mei-Ling Han ◽  
Heidi H. Yu ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Polymyxin B ◽  
Multidrug Resistant ◽  
Combination Group ◽  
Infection Model ◽  
New Delhi ◽  
Content Type ◽  
Antimicrobial Synergy ◽  
Time Kill

ABSTRACTPolymyxins are used as a last-line therapy against multidrug-resistant (MDR) New Delhi metallo-β-lactamase (NDM)-producingKlebsiella pneumoniae. However, polymyxin resistance can emerge with monotherapy; therefore, novel strategies are urgently needed to minimize the resistance and maintain their clinical utility. This study aimed to investigate the pharmacodynamics of polymyxin B in combination with the antiretroviral drug zidovudine againstK. pneumoniae. Three isolates were evaluated in static time-kill studies (0 to 64 mg/liter) over 48 h. Anin vitroone-compartment pharmacokinetic/pharmacodynamic (PK/PD) model (IVM) was used to simulate humanized dosage regimens of polymyxin B (4 mg/liter as continuous infusion) and zidovudine (as bolus dose thrice daily to achieve maximum concentration of drug in broth [Cmax] of 6 mg/liter) againstK. pneumoniaeBM1 over 72 h. The antimicrobial synergy of the combination was further evaluated in a murine thigh infection model againstK. pneumoniae02. In the static time-kill studies, polymyxin B monotherapy produced rapid and extensive killing against all three isolates followed by extensive regrowth, whereas zidovudine produced modest killing followed by significant regrowth at 24 h. Polymyxin B in combination with zidovudine significantly enhanced the antimicrobial activity (≥4 log10CFU/ml) and minimized bacterial regrowth. In the IVM, the combination was synergistic and the total bacterial loads were below the limit of detection for up to 72 h. In the murine thigh infection model, the bacterial burden at 24 h in the combination group was ≥3 log10CFU/thigh lower than each monotherapy againstK. pneumoniae02. Overall, the polymyxin B-zidovudine combination demonstrates superior antimicrobial efficacy and minimized emergence of resistance to polymyxins.

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