Category Archives: C. diff. Research Community

Researchers From North Carolina State University Find That Antibiotics Give C.diff. Nutrient-Rich Environment

Using a mouse model, researchers from North Carolina State University have found that antibiotic use creates a “banquet” for Clostridium difficile (C. diff), by altering the native gut bacteria that would normally compete with C. diff for nutrients. The findings could lead to the development of probiotics and other strategies for preventing C. diff infection.

C. diff is a harmful bacterium that can cause severe, recurrent and sometimes fatal infections in the gut. Although the bacteria are commonly found throughout our environment, C. diff infections primarily occur in patients who are taking, or who have recently finished taking, antibiotics.

“We know that antibiotics are major risk factors for C. diff infection because they alter the gut microbiota, or composition of bacteria in the gut, by eliminating the bacteria that are normally there,” says Casey Theriot, assistant professor of infectious disease at NC State and corresponding author of a paper describing the research. “Our latest work suggests that the microbiota may provide natural resistance to C. diff colonization by competing with C. diff for nutrients in that environment; specifically, for an amino acid called proline.”

Theriot and postdoctoral fellow Joshua Fletcher introduced C. diff to antibiotic-treated mice and monitored their gut environment at four intervals: 0, 12, 24, and 30 hours after introduction. They conducted metabolomic and RNA sequencing analysis of the gut contents and the C. diff at these time points to find out which nutrients the bacteria were “eating.” Metabolomics allowed the team to trace the abundance of the nutrients in the gut, and RNA analysis indicated which genes in the C. diff were active in metabolizing nutrients.

The researchers found that the amount of proline in the gut decreased as the population of C. diff increased. Additionally, the amount of a proline byproduct called 5-aminovalerate also increased, indicating that C. diff was metabolizing the proline. The RNA analysis further confirmed C. diff‘s use of proline, as genes related to proline metabolism in C. diff increased during the early stages of colonization, when proline was abundant.

“We’ve been able to show that in the absence of competition C. diff is metabolizing proline and other amino acids in the mouse model, using it as fuel to survive and thrive,” Theriot says. “Hopefully this information could lead to the development of better probiotics, or ‘good’ bacteria that can outcompete C. diff for nutrients in the gut. The ultimate goal is to control these bacteria in ways that don’t rely solely on antibiotics.”

To review article in its entirety please click on the following link to be redirected:

https://www.sciencedaily.com/releases/2018/03/180328204122.htm

Rutgers University and International Scientists Have Determined the Molecular Target and Mechanism of the Antibacterial Drug fidaxomicin (Trade Name Dificid)

Fidaxomicin was approved in 2011 for treatment of the CDC “urgent threat” bacterial pathogen Clostridium difficile (C. diff) and currently is one of two front-line drugs for treatment of C. diff.

A team of Rutgers University and international scientists has determined the molecular target and mechanism of the antibacterial drug fidaxomicin (trade name Dificid).

Resource:  https://www.sciencedaily.com/releases/2018/03/180329141050.htm

Fidaxomicin also exhibits potent antibacterial activity against other CDC “serious threat” bacterial pathogens, including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Staphylococcus aureus (VRSA), and the tuberculosis bacterium, Mycobacterium tuberculosis. However, the low solubility and low systemic bioavailability of fidaxomicin have precluded use of fidaxomicin for treatment of MRSA, VRSA, and tuberculosis.

To design next-generation fidaxomicin derivatives with improved clinical activity against C. diff and useful clinical activity against MRSA, VRSA, and tuberculosis, it is essential to know how the drug binds to and inhibits its molecular target, bacterial RNA polymerase, the enzyme responsible for bacterial RNA synthesis.

In a paper published in Molecular Cell today, the researchers report results of cryo-electron microscopy (cryo-EM) and single molecule spectroscopy analyses showing how fidaxomicin binds to and inhibits bacterial RNA polymerase.

The researchers report a cryo-EM structure of fidaxomicin bound to Mycobacterium tuberculosis RNA polymerase at 3.5 Å resolution. The structure shows that fidaxomicin binds at the base of the RNA polymerase “clamp,” a part of RNA polymerase that must swing open to allow RNA polymerase to bind to DNA and must swing closed to allow RNA polymerase to hold onto DNA. The structure further shows that fidaxomicin traps the RNA polymerase “clamp” in the open conformation.

The researchers also report results of single-molecule fluorescence spectroscopy experiments that confirm that fidaxomicin traps the RNA polymerase “clamp” in the open conformation and that define effects of fidaxomicin on the dynamics of clamp opening and closing.

The researchers show that fidaxomicin inhibits bacterial RNA polymerase through a binding site and mechanism that differ from those of rifamycins, another class of antibacterial drugs that target bacterial RNA polymerase. The finding that fidaxomicin inhibits bacterial RNA polymerase functions through a different, non-overlapping binding site and mechanism explains why fidaxomicin is able to kill bacterial pathogens resistant to rifamycins and why fidaxomicin is able to function additively when combined with rifamycins.

The new results enable rational, structure-based design of new, improved fidaxomicin derivatives with higher antibacterial potency, higher solubility, and higher systemic bioavailability. Based on the structure of fidaxomicin bound to its target, the researchers identified atoms of fidaxomicin that are not important for binding to the target and thus that can be modified without compromising the ability to bind to the target. The researchers then developed chemical procedures that allow selective attachment of new chemical groups at those atoms, including new chemical groups that can improve potency, solubility, or systemic bioavailability.

“The results set the stage for development of improved fidaxomicin derivatives, particularly improved fidaxomicin derivatives having the solubility and systemic bioavailability needed for treatment of systemic infections, such as MRSA and tuberculosis,” said Ebright, Board of Governors Professor of Chemistry and Chemical Biology and Laboratory Director at the Waksman Institute of Microbiology at Rutgers, who led the research.

In addition to Richard H. Ebright, the research team included Wei Lin, David Degen, Abhishek Mazumder, Dongye Wang, Yon W. Ebright, Richard Y. Ebright, Elena Sineva, Matthew Gigliotti, Aashish Srivastava, Sukhendu Mandal, Yi Jiang, Ruiheng Yin, and Dennis Thomas from Rutgers University; Kalyan Das from KU Leuven; Zhening Zhang and Edward Eng from the National Resource for Automated Molecular Microscopy and the Simons Electron Microscopy Center; Stefano Donadio from NAICONS Srl.; Haibo Zhang and Changsheng Zhang from the Chinese Academy of Sciences Guangzhou.

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https://www.sciencedaily.com/releases/2018/03/180329141050.htm

Immuron Announced First Patients Enrolled In Phase 1/2 (first-in-human) Clinical Trials For Immuron’s IMM-529 For Treatment of C.difficile Infections

The Australian biopharmaceutical company Immuron announced that the first patients have enrolled in phase 1/2 (first-in-human) clinical trials for Immuron’s IMM-529, an oral immunotherapeutic medication for treatment of Clostridium difficile infections (CDI).

As published in MD Mag February 16, 2018

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http://www.mdmag.com/medical-news/a-powerful-new-weapon-in-the-fight-against-clostridium-difficile-infection

According to Dan Peres, MD, senior vice president and head of medical development at Immuron, IMM-529 “has shown promise in successfully treating Clostridium-difficile” through its “unique delivery of antibodies.”

If the trials are successful, IMM-529 may be a powerful new weapon in the global fight against CDI. Peres reports that IMM-529 that has been effective in preclinical studies for prophylactic use, treatment of disease, and the prevention of recurrence in relation to CDI, and that the company is excited to enroll the first patients.

The placebo-controlled study to test the safety, tolerability and efficacy of IMM-529 will take place at Hadassah Medical Center in Jerusalem and include 60 CDI diagnosed patients in the 28 day study.

Patients enrolled in the study, led by Yoseph Caraco, MD, head of the clinical pharmacology unit at Hadassah Medical Center, will receive IMM-529 or a placebo 3 times a day during the 28 -day trial period, and be monitored for 2 additional months, determining any recurrence of the disease.

In a statement, Caraco said that he was optimistic about IMM-529 based on pre-clinical trial results and that IMM-529 could “be the answer we’re all looking for” when it comes to treatment of CDI.

IMM-529 targets CDI in 2 ways: by neutralizing toxin B (TcdB), a cytotoxin responsible for inflammation and diarrhea that characterizes CDI, and by binding Clostridium difficile spores and vegetative cells preventing further colonization. Caraco reported that IMM-529 approaches CDI by “targeting the main virulence factors of the disease with only minor disturbance to the natural biome” which could be extremely valuable in treating CDI.

In the earlier pre-clinical proof-of-concept study by led by Dena Lyras, MD, PhD with Monash University in Melbourne, Australia, IMM-529 was shown to be 80% effective in both the treatment of and prevention of CDI without the use of antibiotics.

In a December 2015 statement from Immuron, Lyras stated that she was “excited by the potential of these therapeutics in treating patients with both the acute and the relapse phase, of the disease.”

According to data supplied by the American Gastroenterological Association, approximately 500,000 people in the US are diagnosed with CDI each year, and CDI-associated deaths range from 14,000 to 30,000 per year.

In the European Union, according to a 2016 study led by Alessandro Cassini, MD, with the European Centre for Disease Prevention and Control in Stockholm, Sweden, more than 150,000 cases of hospital-acquired CDI infections (134,053–173,089; 95% CI) occur each year.

According to Immuron, the cost of CDI globally (calculated by CIDRAP, the Center for Infectious Disease and Policy at the University of Minnesota) is an estimated annual economic burden of more than $10 billion and increases in hypervirulent and antibiotic-resistant strains have led to CDI becoming a major medical concern.

Caraco stated that CDI poses “a growing risk amongst a greater population of patients, including those recently treated with antibiotics, the elderly, institutionalized and hospitalized.”

If IMM-529 is found to be safe and effective in clinical trials, it could prove a significant boon to the global fight against CDI at all 3 stages of the disease.

Surotomycin Failed To Show Benefit Over Vancomycin In a Pivotal Phase 3 Trial To Treat C. difficile Infections

A similar proportion of patients with Clostridium difficile infection showed clinical response at the end of treatment with surotomycin vs. vancomycin in a pivotal phase 3 trial.

However, surotomycin did not demonstrate superiority for key secondary endpoints including sustained clinical response and clinical response over time, and therefore failed to show benefit over vancomycin.

 

As published :  https://www.healio.com/gastroenterology/infection/news/online/%7B3531418d-42aa-4092-a9f2-55ba2ce6dcda%7D/surotomycin-meets-non-inferiority-endpoint-fails-to-show-benefit-over-vancomycin-in-c-difficile

This follows previously reported results of a parallel phase 3 trial in which surotomycin failed to meet non-inferiority criteria relative to vancomycin for primary and key secondary endpoints.

“Surotomycin has a narrow spectrum of activity, demonstrating low resistance rates and rapid activity against C. difficile with similar dose- and time-dependent pharmacodynamics to vancomycin in resolving CDI in a hamster model,” Sahil Khanna, MBBS, of the division of gastroenterology and hepatology at the Mayo Clinic in Rochester, Minn., told Healio Gastroenterology and Liver Disease.

In this second phase 3 trial, “surotomycin demonstrated non-inferiority to vancomycin for CDI clinical response at end of treatment. It was similar to vancomycin for sustained clinical cure.”

In this double-blind, international multicenter trial, Khanna and colleagues randomly assigned 285 patients with confirmed CDI to receive 250 mg oral surotomycin twice daily alternating with placebo twice daily, and 292 to receive 125 mg oral vancomycin four times daily for 10 days.

At the end of treatment, clinical response with surotomycin (83.4%) was non-inferior to vancomycin (82.1%), with a difference of 1.4% (95% CI, 4.9-7.6).

Through 30 to 40 days of follow-up, clinical response over time was not superior to surotomycin, nor was sustained clinical response (63.3% vs. 59%; difference, 4.3%; 95% CI, 3.6-12.2).

Both treatments were generally well tolerated, with typical treatment-emergent adverse events occurring in 52.4% of patients treated with surotomycin and 60.1% of those treated with vancomycin.

“Interestingly, in the hypervirulent strain of CDI, recurrence rate was lower for surotomycin vs. vancomycin,” Khanna said, though he and colleagues noted in the study manuscript that “this finding is nominal due to a lack of multiplicity control.”

Based on the results of these trials, the surotomycin development program has been discontinued, but “the non-inferiority of surotomycin to vancomycin observed in the current trial is in contrast with the parallel trial,” investigators wrote. – by Adam Leitenberger

Disclosures: This study was funded by Merck. Khanna reports he has served as an advisor to Summit Pharmaceuticals and serves as a consultant to Rebiotix and Assembly Biosciences. Please see the full study for a list of all other researchers’ relevant financial disclosures.

SOURECE:  https://www.healio.com/gastroenterology/infection/news/online/%7B3531418d-42aa-4092-a9f2-55ba2ce6dcda%7D/surotomycin-meets-non-inferiority-endpoint-fails-to-show-benefit-over-vancomycin-in-c-difficile

Researchers From Loyola Medicine Retrospectively Studied 100 Vancomycin Taper and Pulse Treatment Patients Treated For Recurrent C. difficile Infection

A tapered and pulsed regimen with vancomycin — with diligent follow-up — can achieve significant cure rates in recurrent Clostridium difficile (C. difficile) infected patients, according to a new study.

Researchers from Loyola Medicine retrospectively studied 100 vancomycin taper and pulse treatment patients treated for recurrent C. difficile infection between January 1, 2009 and December 31, 2014. Their clinic, the study authors wrote, has been a referral center for the infection for the past decade.

To read the article in its entirety please click on the following link:

http://www.mdmag.com/medical-news/pulsed-and-tapered-vancomycin-likely-route-to-recurrent-clostridium-difficile-cure

However, despite the guidelines for treatment of recurrent C. difficile infection being not too different than recurrent episodes – except for the use of vancomycin when the case is severe – there have not been many studies on this vancomycin taper and pulsed dosing. 

The researchers observed that after a referral, the confirmed recurrent C. difficile patients were treated with a vancomycin taper and pulse regimen: a taper of vancomycin to once-daily, followed by alternate day dosing; or once-daily followed by alternate day dosing; followed by every third day, for at least 2 weeks. After this regimen, all patients had 90-day follow-up documentation.

On average, the patients in the clinic were on their third C. difficile diarrhea episode. Half of the patients had also received a standard course of vancomycin, while another third had received some type of vancomycin taper regimen, the researchers said.

Despite the fact that many of these patients were a “treatment experienced” population, 75% of the patients who received a supervised vancomycin taper and pulsed regimen achieved a cure,  study author Stuart Johnson  MD, . He added that the results were further improved for patients who received the expended pulse phase: 81% achieved a cure.

“The findings were not unexpected to us, but I think that many clinicians will be surprised how well a deliberate, prolonged vancomycin taper and pulse regimen – with careful follow up – works,” Johnson said.

There were no significant differences among the patients in terms of gender, age, concomitant antibiotics, proton pump inhibitor use, histamine receptor-2 blocker use, or patients with a regimen greater than 10 weeks in length, the researchers continued.

The researchers added that their finding of improved cure rates with alternate-day dosing plus every third day dosing over strictly alternate-day dosing is consistent with the hypothesis that pulsed dosing can promote a cyclical decrease in spore burden, they wrote. This can also permit the resetting of normal microbiota in the gut.

Johnson concluded that the clinical implications of the study show most recurrent C. difficile patients do not need fecal microbiota transplant (FMT).

“FMT has received an enormous amount of press and this procedure is now widely available throughout the US,” Johnson said. “FMT is attractive because it addresses one of the primary mechanisms involved with recurrent C. difficile infection, a marked disruption of the resident bacteria that populate the intestine and provide an important host defense against C. difficile.

Although physicians screen donor feces for “known pathogens,” not all is known of the potential complications to come from FMT, Johnson said.

“In addition, it appears that efficacy with a carefully supervised vancomycin taper and pulse regimen compare to that achieved with FMT,” Johnson said.

The study, “Vancomycin Taper and Pulsed Regimen with careful Follow up for Patients with Recurrent Clostridium difficile Infection,” was published in the journal Clinical Infectious Diseases.

Norman B. Javitt, M.D. Is Welcomed As a Member Of the C Diff Foundation, R & D Committee

We are pleased to welcome
Norman B. Javitt, M.D. to the
C Diff Foundation.

Dr. Javitt has an extensive professional career in health care.  New York University Medical Center: Instructor, then Assistant Professor Medicine where his career was devoted mostly to research in liver disease, specifically in inborn errors of cholesterol metabolism affecting newborns, and to teaching medical students.

Cornell University Medical School-New York Hospital:  Associate Professor of Medicine, then Professor of medicine and Chief, Division of Gastroenterology the research program continued to grow, attracting many fellows from all over the world.  Also provided care for private patients, both children and adults, with difficult liver problems.

New York University Medical Center:  Professor of Medicine and of Pediatrics, Division chairman Hepatic Diseases April, Research professor 2015-presnt.  At NYUMC Dr. Javitt has been focusing on C. difficile research  and teaching medical students and house staff.  His research interest has also expand to many areas of cholesterol synthesis and metabolism other than just liver disease.

Dr. Javitt has published research papers in age-related macular degeneration, in vitro fertilization, and Alzheimer’s disease.  He has also published more than 150 research papers, in addition to several books and review articles, and presented work at numerous professional meetings and symposia throughout the world.  His work has been supported by the National Institutes of Health, by private foundations and Pharmaceutical companies.  Dr. Javitt is welcomed by fellow researchers in the Research and Development Committee Chaired by Professor Simon M. Cutting, Ph.D…

C. diff. May Carry Risks in Preoperative and Postoperative Patients

 

There are risks for acquiring a C. difficile infection (CDI).

The risks range from the overuse of Antibiotics, Immunosuppressed patients, prolonged hospital stays, being a patient in a long-term care facility, and for the senior population.

There may also be a risk for the surgical patients and the following study explains the study and the results:

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A lengthy study of four surgical specialties has determined that Clostridium difficile infection (CDI) is a major risk factor for postoperative patients, although incidences varied.

Although it has been shown that CDI is associated with increased cost, morbidity and mortality in patients after surgery, this is the first to examine C. difficile rates across multiple surgical specialties (Infect Control Hosp Epidemiol 2017:1-4. doi: 10.1017/ice.2017.158).

“This study has great importance as the landscape of repayment for elective surgical procedures changes,” said the study’s lead author, James Bernatz, MD, a surgeon with the Department of Orthopedics and Rehabilitative Medicine at University of Wisconsin Hospital and Clinics, in Madison. “With more surgeries being reimbursed as bundled payments, hospitals are pressured to limit costs. As C. diff infection has been found to increase length of stay by one week and double the cost of care, it is clearly a postoperative complication to be avoided.”

Dr. Bernatz and his colleagues conducted the study at a 592-bed tertiary care academic center. They used the hospital’s quality improvement database to review admissions to the orthopedic surgery, neurosurgery, trauma surgery and general surgery units from January 2014 through July 2016. Those patients who underwent an inpatient surgical procedure, and did not meet the exclusion criteria, were surveyed.

Case patients were defined as those who underwent an inpatient procedure and subsequently developed a health care–associated CDI, which was defined as a positive polymerase chain reaction (PCR) test result for C. difficile toxin gene recorded more than 72 hours after admission and within 12 weeks of discharge.

They found 52 cases of CDI among 11,310 surgical admissions to four hospital units: general surgery, neurology, orthopedics and trauma. In all 52 cases, patients had a PCR-positive test result more than 72 hours after admission and within 12 weeks of discharge, making the incidence rate 0.80 cases per 1,000 patient-days. The trauma unit had the highest rate at 9.5 CDI cases per 1,000 admissions (11 cases over 1.160 admissions during the study period). General surgery had 30 cases among 3,447 admissions for a rate of 8.7; orthopedics had six cases among 4,339 admissions for a rate of 1.4; and neurology had five cases among 2,364 admissions for a rate of 2.1.

A number of risk factors were surveyed, including the use of antibiotics.

Regarding antibiotic use, the researchers found that the odds of CDI increased 3.34-fold when the perioperative antibiotic is continued more than 24 hours after surgery, outside of the perioperative window. Antibiotic use, other than the perioperative antibiotic, while in the hospital also was associated with 2.2 times greater odds of CDI. And exposure to antibiotics as long as six months before surgery increases the odds of CDI more than threefold.

“Although the surgeon cannot necessarily control the antibiotics prescribed to their patients in the year leading up to surgery, they can control antibiotic administration in the perioperative and postoperative period,” Dr. Bernatz said. “Antibiotics should be limited to one prophylactic preoperative dose, unless 24 hours of antibiotics are indicated. In the immediate postoperative period, antibiotics should be used judiciously.”

Other significant risk factors included number of hospital admissions in the past year and proton pump inhibitor or histamine type 2 receptor blocker use in the previous six months. “Previous studies have shown a correlation between CDI and hospital admission in the previous 3 months,” the researchers wrote. “Our study reports that this association extends to 12 months. We found that the number of hospital admissions in the past year increases the odds of CDI by 133% for each admission.”

A higher American Society of Anesthesiologists (ASA) physical status classification also was a significant risk factor for CDI; ASA IV or V patients were 15 times more likely to develop CDI than those with ASA class I or II disease, according to the researchers.

Dr. Bernatz said additional research is needed to further reveal these links. “Other studies could examine the rate of C. diff infection between operations within one subspecialty to determine if certain operative variables or patient characteristics affect the postoperative risk of C. diff infection,” he said.