07:39am Monday 23 October 2017

Microbiologists and surgeons team up to study airway disease in ICU patients

SAN ANTONIO  — Not long ago, microbiologists at The University of Texas Health Science Center at San Antonio solved a longstanding medical mystery: A common pathogen, Mycoplasma pneumoniae, was known to be involved in disease pathways throughout the body, but no one knew how it worked. Then the microbiologists discovered a toxin produced by M. pneumoniae and began unraveling its secrets.

Now the microbiologists have teamed up with surgeons to study how M. pneumoniae affects patients in intensive care units.

A $190,000 grant from the National Trauma Institute (NTI) is allowing Health Science Center researchers to take their study into ICUs around the country, where they will try to determine how frequently M. pneumoniae infection occurs among patients on ventilators and how it impacts their outcomes.

The study is an example of translational – or “bench-to-bedside” – research, where scientists and clinicians work together to make sure discoveries quickly emerge from laboratories and start benefiting patients. At the same time, clinicians’ observations can spark new areas of inquiry in laboratories.

Joel B. Baseman, Ph.D., the study’s principal investigator and chairman of microbiology and immunology at the UT Health Science Center, calls the collaboration “a terrific marriage between the clinical and basic science disciplines.”

The study was one of seven funded this year by the nonprofit National Trauma Institute, which is committed to supporting translational research projects whose results may affect the practice of medicine in the near term. The National Trauma Institute’s goal is to reduce death and disability resulting from traumatic injuries.

The discovery of a toxin produced by M. pneumoniae, made in Dr. Baseman’s lab and first described in a 2006 publication, laid the groundwork for the current research. Dr. Baseman links the toxin to a range of acute and chronic airway diseases and puts it in the same category as toxins produced by the bacteria that cause pertussis, diphtheria and cholera.

The discovery was made by a team led by Dr. Baseman and T.R. Kannan, Ph.D., assistant professor of microbiology. Afterward, Dr. Baseman’s lab began taking the research in a number of new directions.

The ICU study resulted from conversations between Dr. Baseman and Stephen M. Cohn, M.D., F.A.C.S., professor of surgery at the Health Science Center. They discussed whether M. pneumoniae might be present in trauma patients, particularly in ICUs, and whether it might amplify their health problems.

“For many years we have been searching for a good explanation for why certain patients do extremely well in the ICU on ventilators, while others have an indolent process that ultimately leads to disability and death,” Dr. Cohn said.

Once the partnership between the departments of Microbiology and Surgery formed, Mark Muir, M.D., a surgical resident about to embark on a two-year research fellowship, took on the project. After training with Dr. Baseman’s team, in July 2008 Dr. Muir began the painstaking work of collecting samples from the ICU at University Hospital.

When a patient on a ventilator in the ICU underwent a bronchoscopy – a procedure that involves inserting an instrument into airways to examine them or take samples – the ICU team would take an extra sample and call Dr. Muir. With the consent of the patient’s family, Dr. Muir would take that sample and a blood sample back to the lab for processing. Because samples degrade in a relatively short time, Dr. Muir found himself coming in on nights and weekends to retrieve them.

“I wore out the hallway between the medical school and the hospital,” Dr. Muir said.

Researchers were able to enroll several dozen patients in the study, and a significant number of those tested positive for M. pneumoniae. Detailed results will be published in an upcoming issue of the journal CHEST.

The pilot project data were compelling enough to attract the grant from the National Trauma Institute, which allows researchers to expand the study to ICUs in other states. The researchers have already brought two ICUs, in Los Angeles and Boston, on board, and they’re in discussions with others. The expanded study seeks to validate the percentage of ICU patients on ventilators who carry M. pneumoniae and better establish whether and when the pathogen causes disease in this population.

Dr. Muir, who has completed his research fellowship, will continue to play a role in the study, but surgical resident Ashwini Kumar, M.D., has stepped up to take the lead.

Funding for Dr. Baseman’s original work on M. pneumoniae and for the ICU pilot project came from a center grant from the National Institutes of Health and from the Robert J. Kleberg, Jr. and Helen C. Kleberg Foundation.

Print contact: Sheila Hotchkin, (210) 567-3026


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