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Impact of anaerobic antibacterial spectrum on cystic fibrosis

Researchers from Children’s National Hospital found that broad spectrum antianaerobic therapy had greater and longer lasting effects on the lung microbiome of persons with cystic fibrosis.

Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the chloride ion channel encoding CF transmembrane conductance regulator gene, leading to multiple morbidities and early mortality. In a new clinical study, researchers from Children’s National Hospital found that broad spectrum antianaerobic therapy had greater and longer lasting effects on the lung microbiome of persons with CF.

They found this difference when comparing the microbiology and clinical outcomes in children with CF who were treated with “broad” or “narrow” antianaerobic antibiotics for exacerbations of their disease. While there are many factors that determine whether “narrow” or “broad” spectrum antibiotics are used, the data showed that the recovery of pulmonary function was similar between those groups.

“The findings prove that most providers are following best practices when treating patients with cystic fibrosis using the narrowest spectrum of antibiotics possible, and reserving broad spectrum agents for more advanced disease when culture data shows more resistant bacteria,” says  Michael Bozzella, the study’s lead author.

The study, published in the Pediatric Infectious Disease Journal, analyzed how the spectrum of antibiotics prescribed to patients with cystic fibrosis impacts the population of bacteria in their lungs how it ties back to lung function.

“Research like this improves antibiotic and antimicrobial stewardship,” said Bozzella. “When speaking with families and patients with cystic fibrosis, providers can be more aware of the relationship between lung microbiome, disease state, and antibiotics and create more holistic treatment plans.”

Dr. Bozzella did this research as a fellow at Children’s National and he’s now an Infectious Disease Attending Physician at Children’s Hospital Colorado. Additional authors from Children’s National include: Andrea Hahn, M.D., M.S., Hollis Chaney, M.D.Iman Sami Zakhari, M.D.Anastassios Koumbourlis, M.D., M.P.H. and Robert Freishtat, M.D., M.P.H.

mother helping child with inhaler

Beta-lactam and microbial diversity in cystic fibrosis

mother helping child with inhaler

The study, published in the Journal of Investigative Medicine, examined the hypotheses that beta-lactam antibiotic PK and PD is associated with changes in richness and alpha diversity following treatment of a pulmonary exacerbations and determined associations between antibiotic PK, PD, antibiotic resistance and lung function.

Cystic fibrosis (CF) is a chronic lung disease that affects more than 30,000 people in the United States and 70,000 people worldwide. While this chronic disease is characterized by acute pulmonary exacerbations that are frequently treated with antibiotics, the impact of antibiotics on airway microbial diversity remains a critical knowledge gap.

A new study led by researchers at Children’s National Hospital found that beta-lactam antibiotic pharmacokinetic (PK) and pharmacodynamic (PD) target attainment during treatment is associated with suppressed recovery of microbial diversity, following a pulmonary exacerbation in children and adolescents with CF.

“By laying the groundwork for understanding how antibiotic PK may influence microbial diversity following pulmonary exacerbation, we hope to identify improved ways to guide antibiotic therapy in persons with CF,” says Andrea Hahn, M.D., M.S., an infectious diseases specialist at Children’s National and lead author of the study.

The study, published in the Journal of Investigative Medicine, examined the hypotheses that beta-lactam antibiotic PK and PD is associated with changes in richness and alpha diversity following treatment of a pulmonary exacerbations and determined associations between antibiotic PK, PD, antibiotic resistance and lung function.

“Beta-lactam antibiotics are frequently used to treat pulmonary exacerbations in persons with CF, yet are not routinely optimized,” says Dr. Hahn. “This study demonstrates the importance of beta-lactam PK’s on changes within the airway microbiome and provides context for care providers regarding the potential long-term impacts of antibiotic use in persons with CF, to ensure that we are optimizing therapy with each pulmonary exacerbation.”

Additional authors from Children’s National include: Aszia Burrell, Hollis Chaney, M.D.Iman Sami Zakhari, M.D.Anastassios Koumbourlis, M.D., M.P.H. and Robert Freishtat, M.D., M.P.H.

Andrea Hahn

Pediatric Research names Andrea Hahn, M.D., M.S., early career investigator

Andrea Hahn

“I am honored to be recognized by Pediatric Research and the Society of Pediatric Research (SPR) at large,” said Dr. Hahn. “SPR is an amazing organization filled with excellent scientists, and to be highlighted by them for my work is truly affirming.”

For her work on the impact of bacterial functional and metabolic activity on acute episodes of cystic fibrosis, the journal Pediatric Research recognized Andrea Hahn, M.D., M.S., as Pediatric Research’s Early Career Investigator.

Cystic fibrosis is an autosomal recessive genetic disease, affecting more than 70,000 people worldwide. The condition’s morbidity and mortality are recurrent and result in a progressive decline of lung function.

“I am honored to be recognized by Pediatric Research and the Society of Pediatric Research (SPR) at large,” said Dr. Hahn. “SPR is an amazing organization filled with excellent scientists, and to be highlighted by them for my work is truly affirming.”

The exact mechanisms of the bacteria that chronically infect the airway triggering acute cystic fibrosis episodes, also known as pulmonary exacerbations, remain unclear. Dr. Hahn’s research is one of the few to explore this gap and found an association with long-chain fatty acid production in cystic fibrosis inflammation.

“As a physician-scientist, there are many competing priorities between developing and executing good science — including writing manuscripts and grants — and providing excellent patient care both directly and through hospital-wide quality improvement initiatives,” said Dr. Hahn. “It is often easier to have successes and feel both effective and appreciated on the clinical side. This recognition of my scientific contributions to the medical community is motivating me to continue pushing forward despite the setbacks that often come up on the research side.”

The exposure to many programs and institutions gave Dr. Hahn the foundation to create a research program at Children’s National that helps decipher the complexities of antibiotic treatment and how it changes the airway microbiome of people with cystic fibrosis. The program also explores the impacts of antibiotic resistance and beta-lactam pharmacokinetics/pharmacodynamics (PK/PD) — the oldest class of antibiotics used to treat infections.

Dr. Hahn believes that the people and environment at Children’s National Hospital allowed her to grow and thrive as a physician-scientist.

“I was initially funded through an internal K12 mechanism, which was followed up by Foundation support, which was only possible because of the strong mentorship teams I have been able to build here at Children’s National,” said Dr. Hahn. “My division chief has also been very supportive, providing me with both protected time as well as additional resources to build my research lab.”

She is particularly appreciative of Robert Freishtat, M.D., M.P.H, senior investigator at the Center for Genetic Medicine Research, and Mary Callaghan Rose (1943-2016).

“Robert Freishtat has been a great advocate for me, and I am indebted to him for my success thus far in my career,” said Dr. Hahn. “Likewise, I want to specifically recognize Mary Rose. She was a great scientist at Children’s National until her death in 2016. She gave me the initial opportunity and support to begin a career studying cystic fibrosis, and she is missed dearly.”

You can learn more about Dr. Hahn’s research in this Pediatric Research article.

girl with cystic fibrosis getting breathing treatment

The role of long-chain fatty acids in cystic fibrosis inflammation

girl with cystic fibrosis getting breathing treatment

A recent study sheds light on the microbiologic triggers for lung inflammation and pulmonary exacerbations in cystic fibrosis.

Cystic fibrosis is an autosomal recessive disease that affects more than 70,000 people worldwide and results in a progressive decline of lung function. Patients with cystic fibrosis experience intermittent episodes of acute worsening of symptoms, commonly referred to as pulmonary exacerbations. While Staphylococcus aureus and Pseudomonas aeruginosa are thought to contribute to both lung inflammation and pulmonary exacerbations, the microbiologic trigger for these events remains unknown. Andrea Hahn, M.D., M.S., and her colleagues at Children’s National Hospital recently shed light on this matter by studying the changes in bacterial metabolic pathways associated with clinical status and intravenous (IV) antibiotic exposure in cystic fibrosis patients.

The researchers found increased levels of long-chain fatty acids (LCFAs) after IV antibiotic treatment in patients with cystic fibrosis. LCFAs have previously been associated with increased lung inflammation in asthma, but this is the first report of LCFAs in the airway of people with cystic fibrosis. This research indicates that bacterial production of LCFAs may be a contributor to inflammation in people with cystic fibrosis and suggests that future studies should evaluate LCFAs as predictors of pulmonary exacerbations.

Additional authors from Children’s National include: Hollis Chaney, M.D., Iman Sami Zakhari, M.D., Anastassios Koumbourlis, M.D., M.P.H. and Robert Freishtat, M.D., M.P.H.

Read the full study in Pediatric Research.

Drs. Dewesh Agrawal, Andrew Dauber, Robert Freishtat, Vittorio Gallo

Four Children’s National Hospital leaders named to APS

Drs. Dewesh Agrawal, Andrew Dauber, Robert Freishtat, Vittorio Gallo

Drs. Dewesh Agrawal, Andrew Dauber, Robert Freishtat and Vittorio Gallo were named as 2021 American Pediatric Society members.

The American Pediatric Society (APS) has announced 55 new members, four of which are experts from Children’s National Hospital. Founded in 1888, the APS is the first and most prestigious academic pediatric organization in North America.

APS members are recognized child health leaders of extraordinary achievement who work together to shape the future of academic pediatrics. New members are nominated by current members through a process that recognizes individuals who have distinguished themselves as child health leaders, teachers, scholars, policymakers and/or clinicians.

“Our members represent the most distinguished and accomplished academic leaders in pediatrics whose outstanding work has advanced child health,” said APS President Steven Abman, M.D. “I am honored to welcome this exceptional group of individuals to the APS. The APS is especially looking forward to the active engagement of our membership with many exciting programs within the organization that are directed towards improvements in academic pediatric medicine, including more vigorous approaches to express our values of anti-racism, equity, diversity and inclusion.”

APS 2021 active new members from Children’s National are:

  • Dewesh Agrawal, M.D., vice-chair for Medical Education at Children’s National. Agrawal’s career has been marked by academic honors and teaching awards at every stage of his training and faculty employment. He has relentlessly devoted his energy to improving the educational experience for students, residents and fellows at Children’s National.
  • Andrew Dauber, M.D., M.M.Sc., chief of Endocrinology at Children’s National. Dr. Dauber’s leadership is reflected, nationally and internationally, in his ability to create research consortia, bringing together investigators to tackle complex questions. For example, he leads an NIH-funded consortium on the genetics of short statures, with multiple top children’s hospitals as partners. He also leads a large clinical trial testing a novel therapeutic agent for genetic short stature.
  • Robert Freishtat, M.D., M.P.H., senior investigator in the Center for Genetic Medicine of the Children’s National Research Institute (CNRI). Dr. Freishtat has authored or co-authored more than 100 articles and book chapters in the fields of pediatric lung injury, asthma, obesity, exosomes and emergency medicine. His research has been continuously funded by the NIH since 2003.
  • Vittorio Gallo, Ph.D., chief research officer at Children’s National and scientific director of CNRI. Dr. Gallo’s scientific success is attested to by over 130 peer-reviewed publications, many in very high-profile journals, as well as over 30 review articles and book chapters. He has received many national and international awards, including the NINDS Javits award in Neuroscience in 2018. Dr. Gallo has served on the editorial boards of many neuroscience journals, including Glia and the Annual Review in Neuroscience, and has been reviewing editor for the Journal of Neuroscience, all of which is a testament to the tremendous impact that his studies have had on the advancement of neurosciences.

“These new members represent multiple areas of Children’s National and have all leveraged the intersection of science, medicine and clinical education to make advances in their field of study,” said Stephen J. Teach, M.D., M.P.H., chair of the Department of Pediatrics at Children’s National. “Their work has, and will continue to, advance pediatric health care, and I congratulate them on their APS membership.”

bacterial extracellular vesicle

Once overlooked cellular messengers could combat antibiotic resistance

bacterial extracellular vesicle

Children’s National Hospital researchers for the first time have isolated bacterial extracellular vesicles from the blood of healthy donors. The team theorizes that the solar eclipse lookalikes contain important signaling proteins and chromatin, DNA from the human host.

Children’s National Hospital researchers for the first time have isolated bacterial extracellular vesicles from the blood of healthy donors, a critical step to better understanding the way gut bacteria communicate with the rest of the body via the bloodstream.

For decades, researchers considered circulating bacterial extracellular vesicles as bothersome flotsam to be jettisoned as they sought to tease out how bacteria that reside in the gut whisper messages to the brain.

There is a growing appreciation that extracellular vesicles – particles that cells naturally release – actually facilitate intracellular communication.

“In the past, we thought they were garbage or noise,” says Robert J. Freishtat, M.D., MPH, associate director, Center for Genetic Medicine Research at Children’s National Research Institute. “It turns out what we throw away is not trash.”

Kylie Krohmaly, a graduate student in Dr. Freishtat’s laboratory, has isolated from blood, extracellular vesicles from Escherichia coli and Haemophilus influenzae, common bacteria that colonize the gut, and validated the results via electron microscopy.

“The images are interesting because they look like they have a bit of a halo around them or penumbra,” Krohmaly says.

The team theorizes that the solar eclipse lookalikes contain important signaling proteins and chromatin, DNA from the human host.

“It’s the first time anyone has pulled them out of blood. Detecting them is one thing. Pulling them out is a critical step to understanding the language the microbiome uses as it speaks with its human host,” Dr. Freishtat adds.

Krohmaly’s technique is so promising that the Children’s National team filed a provisional patent.

The Children’s research team has devised a way to gum up the cellular works so that bacteria no longer become antibiotic resistant. Targeted bacteria retain the ability to make antibiotic-resistance RNA, but like a relay runner dropping rather than passing a baton, the bacteria are thwarted from advancing beyond that step. And, because that gene is turned off, the bacteria are newly sensitive to antibiotics – instead of resistant bacteria multiplying like clockwork these bacteria get killed.

“Our plan is to hijack this process in order to turn off antibiotic-resistance genes in bacteria,” Dr. Freishtat says. “Ultimately, if a child who has an ear infection can no longer take amoxicillin, the antibiotic would be given in tandem with the bacteria-derived booster to turn off bacteria’s ability to become antibiotic resistant. This one-two punch could become a novel way of addressing the antibiotic resistance process.”

ISEV2020 Annual Meeting presentation
(Timing may be subject to change due to COVID-19 safety precautions)
Oral with poster session 3: Neurological & ID
Saturday May 23, 2020, 5 p.m. to 5:05 p.m. (ET)
“Detection of bacterial extracellular vesicles in blood from healthy volunteers”
Kylie Krohmaly, lead author; Claire Hoptay, co-author; Andrea Hahn, M.D., MS, infectious disease specialist and co-author; Robert J. Freishtat, M.D., MPH, associate director, Center for Genetic Medicine Research at Children’s National Research Institute and senior author.