American College of Physicians: Internal Medicine — Doctors for Adults ®

Thursday, December 8, 2016

The how-to guide for Mycobacterium chimaera

A few cases at a time, the Mycobacterium chimaera outbreak associated with heater cooler units (HCU) continues to grow. For reasons unclear to me, the response from CDC and FDA to this train wreck in slow motion has been underwhelming. We continue to field calls from hospitals struggling to deal with an approach to the outbreak.

On today's IDSA list-serv (IDea Exchange) Dr. Luther Rhodes wrote: ”The silence is deafening. I call on those physicians with hands on experience in evaluating post open heart patients referred to ID for evaluation of concerns, signs or symptoms of possible NTM infection to speak up loudly and clearly. Lessons learned, protocols developed, evaluation and testing tools learned dealing with large scale regional patient notification should in my opinion be shared …”

We have posted several times on this topic, but I thought it might be useful to summarize how a hospital could approach this problem in a single post. To view older posts, type chimaera in the search box in the top right hand corner of your display.

Step 1: Determination of risk

Whether you have seen a case or not, the first question is whether your hospital has used the LivaNova Sorin T3 heater cooler unit (HCU) in the last six years. If the answer is no, there is no immediate action you need to take. If yes, then the investigation begins, as you must assume the units are contaminated, regardless of the manufacturing date.

Step 2: Risk mitigation

If you are currently using the LivaNova (Sorin) T3 unit, the most important risk mitigation strategy is to get the units out of the operating room. The molecular epidemiology clearly points to contamination of the HCUs at the manufacturing facility, which allows the units to produce an infectious bioaerosol that contaminates the operative field. Separation of this bioaerosol from the operative field is the key to eliminating the risk. Why the FDA won't clearly state this is very puzzling.

At the University of Iowa Hospitals and Clinics our engineers were able to quickly (within a few days) devise a solution by creating a 6” x 6” hole through the operating room wall on the semi-restricted side of the room. The area identified for creation of this portal was determined by hose access to the OR table with minimal interference with staff and equipment; access to power; and the ability to leave proper corridor width per life safety code.

Testing demonstrated that positive pressure was able to be maintained in the OR after creation of the portal. The portal itself with a sliding door was constructed of Corian in some cases and stainless steel in others. A hose protection mat was placed in the ORs to protect the HCU hoses and to provide a ramp effect for equipment to be relocated as needed during the cases. One advantage of the T3 HCU is that remotes can be purchased that allow the perfusionist in the OR to control the HCU located outside of the room.

Once the HCUs were moved out of the OR, we demonstrated no difficulty with appropriate heating or cooling. Remember, given the long incubation and detection period of these infections (maximum 6 years to date), if you do not eliminate the risk now, you will likely be chasing cases for many years with no end in sight.

We do not believe that culturing HCUs for M. chimaera is helpful. Most laboratories are not adept at performing environmental cultures for mycobacteria, so the negative predictive value of cultures in this setting is poor. In other words, if cultures are negative, you cannot assume that your machines are not contaminated. Moreover, even when cultures are performed in expert labs, the culture results for any given HCU are not consistent over time; they may be negative at first sampling, then positive on subsequent samples, or vice versa. And it has yet to be demonstrated that once a HCU has tested positive it can be successfully decontaminated, which is an additional reason that we believe that elimination of risk requires removal of the HCUs from the OR.

Follow manufacturer's recommendations for cleaning and disinfection of HCUs.

Step 3: Case identification and notification
1. Develop a line list of potentially exposed patients by determining exposure to HCUs over the past 6 years. At our hospital, we found that the easiest way to do this was to identify whether a perfusionist was assigned to the operative case as identified via billing records. It is important to note that you will need to include off pump cardiac cases, since the HCU is typically on “stand by” status, turned on and running in the OR, even if the patient is not on cardiopulmonary bypass. Also, cardiopulmonary bypass is not restricted to cardiac cases; some lung and liver transplants are performed with cardiopulmonary bypass.
2. Notify potentially exposed patients. We began by sending a letter, explaining the problem and asked patients to call a toll free number to speak with a nurse who did a symptom screen on the phone. Patient who screened positive, were advised to see their local physician or to come to a clinic that we set up for evaluation. A letter to physicians was included with the patient letter and patients were instructed to take the letter to their physician. Patients who did not call in response to the letter were contacted by phone and screened. Our marketing and communications group was very helpful in developing patient materials. They also prepared press releases and established a webpage on the hospital's website with information for patients and healthcare providers. It's important to note that patients who are asymptomatic presently will still be at risk for development of infection for several years, so they need to be instructed to seek medical attention should they develop symptoms in the future. The patients at highest risk are those with implants (e.g., cardiac valves, vascular prostheses, ventricular assist devices), though a few cases have been reported in patients without implants.
3. Notify referring providers and internal physicians who may end up seeing infected patients. We sent letters explaining the infection to all referring providers and broadcast emails to our providers internally. It's important for providers to think about this infection when they evaluate potentially exposed patients with culture-negative endocarditis, fever of unknown origin, unexplained weight loss, or unexplained granulomatous inflammatory processes, including sarcoidosis. Obviously it's important for your infectious diseases physicians to be made aware, but other physicians may be involved with cases as well. One of our cases was simultaneously being evaluated by a hematologist, a hepatologist, and an ophthalmologist for a disseminated granulomatous process. Once you have developed your list of potentially exposed patients, you can run it against a list of patients with the aforementioned diagnoses, and further review any patients who appear on both lists.
4. Ask your lab to produce a list of patients who had MAC isolated from blood, bone marrow or wounds in the last 6 years. Run this list against your list of potentially exposed patients to identify any matches for further review.
5. Any patient with a consistent syndrome should have 2-3 mycobacterial blood cultures obtained. If suspicion is high and mycobacterial blood cultures are negative, consider obtaining bone marrow biopsy for histopathology and culture.
6. If mycobacterial cultures grow MAC, depending on your lab's capabilities, you may need to send the isolates to a reference lab for species identification.
7. Report M. chimaera cases to the FDA via MedWatch.

Given that the implicated heater cooler unit is the predominant brand, many hospitals will be embarking on an investigation, so hopefully they will find this information of value.

Useful publications:
Latest review (Infection Control and Hospital Epidemiology), November 2016
IDWeek Presentation of US Multicenter Investigation, October 29, 2016
MMWR, October 14, 2016
CDC guidance
FDA guidance, October 15, 2016
Emerging Infectious Diseases, June 2016

Clinical Infectious Diseases, July 2015

Michael B. Edmond, MD, FACP, is a hospital epidemiologist in Iowa City, IA, with a focus on improving the quality and safety of health care, and sees patients in the inpatient and outpatient settings. This post originally appeared at the blog Controversies in Hospital Infection Prevention.

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Members of the American College of Physicians contribute posts from their own sites to ACP Internistand ACP Hospitalist. Contributors include:

Albert Fuchs, MD
Albert Fuchs, MD, FACP, graduated from the University of California, Los Angeles School of Medicine, where he also did his internal medicine training. Certified by the American Board of Internal Medicine, Dr. Fuchs spent three years as a full-time faculty member at UCLA School of Medicine before opening his private practice in Beverly Hills in 2000.

And Thus, It Begins
Amanda Xi, ACP Medical Student Member, is a first-year medical student at the OUWB School of Medicine, charter class of 2015, in Rochester, Mich., from which she which chronicles her journey through medical training from day 1 of medical school.

Ira S. Nash, MD, FACP, is the senior vice president and executive director of the North Shore-LIJ Medical Group, and a professor of Cardiology and Population Health at Hofstra North Shore-LIJ School of Medicine. He is Board Certified in Internal Medicine and Cardiovascular Diseases and was in the private practice of cardiology before joining the full-time faculty of Massachusetts General Hospital.

Zackary Berger
Zackary Berger, MD, ACP Member, is a primary care doctor and general internist in the Division of General Internal Medicine at Johns Hopkins. His research interests include doctor-patient communication, bioethics, and systematic reviews.

Controversies in Hospital Infection Prevention
Run by three ACP Fellows, this blog ponders vexing issues in infection prevention and control, inside and outside the hospital. Daniel J Diekema, MD, FACP, practices infectious diseases, clinical microbiology, and hospital epidemiology in Iowa City, Iowa, splitting time between seeing patients with infectious diseases, diagnosing infections in the microbiology laboratory, and trying to prevent infections in the hospital. Michael B. Edmond, MD, FACP, is a hospital epidemiologist in Iowa City, IA, with a focus on understanding why infections occur in the hospital and ways to prevent these infections, and sees patients in the inpatient and outpatient settings. Eli N. Perencevich, MD, ACP Member, is an infectious disease physician and epidemiologist in Iowa City, Iowa, who studies methods to halt the spread of resistant bacteria in our hospitals (including novel ways to get everyone to wash their hands).

db's Medical Rants
Robert M. Centor, MD, FACP, contributes short essays contemplating medicine and the health care system.

Suneel Dhand, MD, ACP Member
Suneel Dhand, MD, ACP Member, is a practicing physician in Massachusetts. He has published numerous articles in clinical medicine, covering a wide range of specialty areas including; pulmonology, cardiology, endocrinology, hematology, and infectious disease. He has also authored chapters in the prestigious "5-Minute Clinical Consult" medical textbook. His other clinical interests include quality improvement, hospital safety, hospital utilization, and the use of technology in health care.

Juliet K. Mavromatis, MD, FACP, provides a conversation about health topics for patients and health professionals.

Dr. Mintz' Blog
Matthew Mintz, MD, FACP, has practiced internal medicine for more than a decade and is an Associate Professor of Medicine at an academic medical center on the East Coast. His time is split between teaching medical students and residents, and caring for patients.

Everything Health
Toni Brayer, MD, FACP, blogs about the rapid changes in science, medicine, health and healing in the 21st century.

Vineet Arora, MD, FACP, is Associate Program Director for the Internal Medicine Residency and Assistant Dean of Scholarship & Discovery at the Pritzker School of Medicine for the University of Chicago. Her education and research focus is on resident duty hours, patient handoffs, medical professionalism, and quality of hospital care. She is also an academic hospitalist.

Glass Hospital
John H. Schumann, MD, FACP, provides transparency on the workings of medical practice and the complexities of hospital care, illuminates the emotional and cognitive aspects of caregiving and decision-making from the perspective of an active primary care physician, and offers behind-the-scenes portraits of hospital sanctums and the people who inhabit them.

Gut Check
Ryan Madanick, MD, ACP Member, is a gastroenterologist at the University of North Carolina School of Medicine, and the Program Director for the GI & Hepatology Fellowship Program. He specializes in diseases of the esophagus, with a strong interest in the diagnosis and treatment of patients who have difficult-to-manage esophageal problems such as refractory GERD, heartburn, and chest pain.

I'm dok
Mike Aref, MD, PhD, FACP, is an academic hospitalist with an interest in basic and clinical science and education, with interests in noninvasive monitoring and diagnostic testing using novel bedside imaging modalities, diagnostic reasoning, medical informatics, new medical education modalities, pre-code/code management, palliative care, patient-physician communication, quality improvement, and quantitative biomedical imaging.

Informatics Professor
William Hersh, MD, FACP, Professor and Chair, Department of Medical Informatics & Clinical Epidemiology, Oregon Health & Science University, posts his thoughts on various topics related to biomedical and health informatics.

David Katz, MD
David L. Katz, MD, MPH, FACP, is an internationally renowned authority on nutrition, weight management, and the prevention of chronic disease, and an internationally recognized leader in integrative medicine and patient-centered care.

Just Oncology
Richard Just, MD, ACP Member, has 36 years in clinical practice of hematology and medical oncology. His blog is a joint publication with Gregg Masters, MPH.

Kevin Pho, MD, ACP Member, offers one of the Web's definitive sites for influential health commentary.

MD Whistleblower
Michael Kirsch, MD, FACP, addresses the joys and challenges of medical practice, including controversies in the doctor-patient relationship, medical ethics and measuring medical quality. When he's not writing, he's performing colonoscopies.

Medical Lessons
Elaine Schattner, MD, FACP, shares her ideas on education, ethics in medicine, health care news and culture. Her views on medicine are informed by her past experiences in caring for patients, as a researcher in cancer immunology, and as a patient who's had breast cancer.

Mired in MedEd
Alexander M. Djuricich, MD, FACP, is the Associate Dean for Continuing Medical Education (CME), and a Program Director in Medicine-Pediatrics at the Indiana University School of Medicine in Indianapolis, where he blogs about medical education.

More Musings
Rob Lamberts, MD, ACP Member, a med-peds and general practice internist, returns with "volume 2" of his personal musings about medicine, life, armadillos and Sasquatch at More Musings (of a Distractible Kind).

David M. Sack, MD, FACP, practices general gastroenterology at a small community hospital in Connecticut. His blog is a series of musings on medicine, medical care, the health care system and medical ethics, in no particular order.

Reflections of a Grady Doctor
Kimberly Manning, MD, FACP, reflects on the personal side of being a doctor in a community hospital in Atlanta.

The Blog of Paul Sufka
Paul Sufka, MD, ACP Member, is a board certified rheumatologist in St. Paul, Minn. He was a chief resident in internal medicine with the University of Minnesota and then completed his fellowship training in rheumatology in June 2011 at the University of Minnesota Department of Rheumatology. His interests include the use of technology in medicine.

Technology in (Medical) Education
Neil Mehta, MBBS, MS, FACP, is interested in use of technology in education, social media and networking, practice management and evidence-based medicine tools, personal information and knowledge management.

Peter A. Lipson, MD
Peter A. Lipson, MD, ACP Member, is a practicing internist and teaching physician in Southeast Michigan. The blog, which has been around in various forms since 2007, offers musings on the intersection of science, medicine, and culture.

Why is American Health Care So Expensive?
Janice Boughton, MD, FACP, practiced internal medicine for 20 years before adopting a career in hospital and primary care medicine as a locum tenens physician. She lives in Idaho when not traveling.

World's Best Site
Daniel Ginsberg, MD, FACP, is an internal medicine physician who has avidly applied computers to medicine since 1986, when he first wrote medically oriented computer programs. He is in practice in Tacoma, Washington.

Other blogs of note:

American Journal of Medicine
Also known as the Green Journal, the American Journal of Medicine publishes original clinical articles of interest to physicians in internal medicine and its subspecialities, both in academia and community-based practice.

Clinical Correlations
A collaborative medical blog started by Neil Shapiro, MD, ACP Member, associate program director at New York University Medical Center's internal medicine residency program. Faculty, residents and students contribute case studies, mystery quizzes, news, commentary and more.

Interact MD
Michael Benjamin, MD, ACP member, doesn't accept industry money so he can create an independent, clinician-reviewed space on the Internet for physicians to report and comment on the medical news of the day.

PLoS Blog
The Public Library of Science's open access materials include a blog.

White Coat Rants
One of the most popular anonymous blogs written by an emergency room physician.

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