November 5, 2015 — A hospital in Pennsylvania announced last week that it had begun notifying 1,300 patients of their potential exposure to a deadly bacteria.Large Blog Image

So far, the hospital has confirmed that 8 surgical patients were infected with the bacteria, 4 — now 5 — of whom died. Hospital officials are acknowledging that the infection likely “contributed” to these deaths.

The infections were caused by “NTM” — or, nontuberculous mycobacteria — which may also be referred to as “atypical” mycobacteria.



  • Update (12/1/2015): As many as 9 patients may have been infected with mycobacteria following open-heart surgery performed at Wellspan York Hospital since 2011.
  • Update (11/11/2015): Four — now 5 — of these infected patients may have died due to a contaminated heater-cooler device.
  • Last month, the FDA and CDC notified the public of this device’s risk of patient infection, death.
  • U.S. public health officials investigated a similar outbreak last year at a hospital in South Carolina, but it’s cause remains unclear.
  • Update (11-10-2015): A second mycobacterial outbreak linked to a heater-cooler device has been confirmed at Penn State Milton S. Hershey Medical Center (Hershey, PA).

Each of the 1,300 “at risk” patients underwent open-heart surgery at Wellspan York Hospital, in York (PA), between Oct. 1, 2011 and July 24, 2015.Image 3

The hospital’s investigation — assisted by both the Pennsylvania Department of Health and the U.S. Centers for Disease Control and Prevention (CDC) — determined that a contaminated heater-cooler device was the source of the mycobacteria.

Heater-cooler devices are used in the operating room primarily to control the temperature of the patient’s blood during open-heart surgery, but they may also be used to provide heated and cooled water to other devices, including warming-cooling blankets.

Update — November 10, 2015:  A second mycobacterial outbreak linked to a heater-cooler device has been identified at Penn State Milton S. Hershey Medical Center (Hershey, PA): “Hershey Medical Center reports same infection seen in York Hospital patients” — York Dispatch (November 10, 2015)

Although these devices ordinarily do not come into direct contact with the patient, investigators have concluded that the heater-cooler device can emit contaminated aerosols into the operating room’s air, posing an infection risk.

Wellspan York’s heater-cooler device is manufactured by The Sorin Group (Germany).   

Mycobacterium chimaera

According to Wellspan York’s president, the outbreak was caused by Mycobacterium chimarea, which are commonly found in soil and water — and even in tap water.

These mycobacteria are not transmitted from one patient to another, however, and they are called “opportunistic” organisms, because they generally only infect patients who are already ill or have compromised immune systems.

Infections of M. chimaera are usually treatable, although patients may not know they are infected. These organisms grow slowly, causing infected patients not to display symptoms until several months later, or longer.

Acid-fast bacilli
Nontuberculous mycobacteria, or “NTM.” (From: CDC)

Symptoms of a mycobacterial infection include fever, pain, redness, and pus around the surgical incision.

Wellspan York decided to notify these 1,300 potentially exposed patients as a precaution, so that those who are infected can be treated.

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According to officials, Wellspan York’s patients are no longer at risk of infection because the hospital replaced its heater-cooler devices with new equipment in July.

Wellspan York issued a press release last week providing additional details about the outbreak: “WellSpan York Hospital Notifies Open-Heart Surgery Patients of Possible Infection Risk.”

Greenville Memorial Hospital’s mycobacterial outbreak in 2014

It’s unclear whether Wellspan York Hospital’s deadly outbreak could have been avoided.

But the circumstances of this outbreak are similar to those of another deadly outbreak that the Centers for Disease Control and Prevention (CDC) investigated last year in South Carolina at Greenville Memorial Hospital.

In that outbreak, health officials sought to identify the cause of several infections of mycobacteria that were also linked to open-heart surgical procedures.

M. abscessus
Mycobacterium abscessus (From: CDC)

Fifteen of the hospital’s patients were infected with M. abscessus, four of whom died. This type of NTM, like Wellspan York’s M. chimaera, may be found in soil or water.

But whereas M. abscessus grows rapidly, M. chimaera is a slow-growing type of NTM.

Greenville Memorial initially suspected the outbreak’s cause to be contaminated medical equipment used in the operating room, but officials could not link the deadly outbreak directly to any specific device.

But, as I wrote last year, Greenville Memorial officials removed the suspected equipment from the operating room, reporting that no new infections of mycobacteria have been identified.

Drawing attention to the heater-cooler device, the hospital issued a statement last year that read, in part, that this removed equipment — which the hospital used for cardiopulmonary perfusion — “used a closed system in which cooled or heated water encased in tubes is run in close proximity to patient blood (also encased in tubes) as part of a heating/cooling procedure used in cardiac surgeries.”

Documents reveal that, at the time of its outbreak in 2014, Greenville Memorial used the Stockert 3T — a heater-cooler device manufactured by The Sorin Group.


While not entirely convinced of the equipment’s role, Greenville Memorial concluded that contaminated tap water was to blame for its deadly outbreak in 2014.  

The hospital used tap water to fill the tank inside the heater-cooler device prior to performing open-heart surgery (although health officials now recommend using only sterile or filtered water).

In the popular article I wrote in June 2014 about Greenville Hospital’s outbreak — see: “4th Patient Dies, 15 Infected at Greenville Memorial Hospital Linked to Contaminated Tap Water” — I discuss the potential for contaminated medical equipment, including heater-cooler devices, to transmit deadly infections during open-heart surgery.Image 2

No federal safety alerts, notifications, recalls or warnings alerting U.S. hospitals to the potential risk of heater-cooler devices becoming contaminated with and transmitting infectious bacteria were issued in response to Greenville Memorial’s outbreak.

A national concern

I concluded last year that Greenville Memorial Hospital might be the tip of an iceberg with national implications, and that other U.S. hospitals had likely encountered similar types of mycobacterial outbreak following open-heart surgery.

Mycobacteria may be identified in the tap water of any hospital, suggesting that other hospitals performing open-heart surgery would reasonably be susceptible to the same type of deadly outbreak as Greenville Memorial’s.

Wellspan York’s outbreak — update: along with Hershey Medical Center’s outbreak, too — confirms that, indeed, mycobacterial outbreaks following open-heart surgery are a national concern and may be more widespread than realized.

As the York Dispatch newspaper reported two weeks ago, an epidemiologist at the CDC acknowledged my concerns about Greenville Memorial’s outbreak last year and that he has “heard comments” from colleagues suspecting that other previously investigated mycobacterial outbreaks in the U.S. may have been due to a contaminated heater-cooler device.

Hospitals were not aware of these suspicions, because federal officials did not publicize the risk of these devices until recently, after learning of Wellspan York’s outbreak.

Whether these types of outbreaks linked to contaminated heater-cooler devices could be caused by other microorganisms like fungi or Pseudomonas spp., not just mycobacteria, seems plausible, although the FDA and CDC have limited the scope of these outbreaks solely to mycobacteria.

Sorin’s first alert: July 2014

Last year, on July 14, 2014, The Sorin Group (the manufacturer of York Hospital’s implicated heater-cooler device) issued an “Important Information” alert that warned customers of the risk of just the type of outbreak that afflicted Wellspan York: mycobacterial infections associated with contamination of this company’s heater-cooler devices.

This alert further explained that strict adherence to the manufacturer’s cleaning, disinfection and maintenance procedures is necessary to prevent microbiological growth and the formation of biofilms inside the heater-cooler device — and, therefore, to prevent patient infections.

According to the York Dispatch, Wellspan York Hospital has not confirmed ever receiving this initial notice.

A European 2015 alert

The European Centre for Disease Prevention and Control (ECDC) — Europe’s version of the CDC in the U.S. — expressed concerned about the risk of mycobacterial infections during open-heart surgery months before the CDC.

In April, 2015, the ECDC issued a safety alert that read: “Since 2011, cases of infection caused by Mycobacterium chimaera have been detected in patients having previously undergone cardiac surgery in Europe.”

This alert also advised doctors to consider testing patients who have undergone open-heart surgery “specifically for slow-growing non-tuberculous mycobacteria such as M. chimaera” — adding that regulatory bodies should be “aware of the potential association of invasive cardiovascular infections caused by M. chimaera with heater-cooler units.”

(It is unclear whether the CDC was aware of the potential association between mycobacterial infections and heater-cooler devices when it investigated Greenville Memorial’s deadly outbreak in 2014.)

This preemptive action by the ECDC in April 2015 is reminiscent of Europe’s more prompt response to deadly “superbug” outbreaks linked to contaminated duodenoscopes.

Whereas this risk was first publicized in Europe in 2013 and 2014, the FDA did not notify U.S. hospitals until 2015 that the designs of duodenoscopes might cause their complex structures to retain infectious bacteria, even if they are cleaned as instructed by the manufacturer.

Sorin’s second alert: June 2015

The Sorin Group issued a second alert — called a “Field Safety Notice” —  a year later, in June 2015, alerting customers that failure to properly disinfect and otherwise maintain its heater-cooler devices (as detailed in the manufacturer’s instructions) poses an increased risk of organisms growing in the heater-cooler device and infecting patients.

According to this notice, “contamination of heater cooler units with other waterborne pathogens, like Mycobacterium abscessus …, has also been detected in the water of certain heater-cooler units.”

Mycobacterium abscessus was the type of mycobacteria that officials identified as the cause of Greenville Memorial’s deadly outbreak in 2014.

Among other advice, Sorin’s “Field Safety Notice” recommends that its “customers”:

  • on a bi-weekly basis, microbiologically sample the air in the operating room for non-tuberculous mycobacteria (when the heater-cooler device is operating); and
  • also on a bi-weekly basis, microbiologically monitor the quality of the water in the heater-cooler device for non-tuberculous mycobacteria;
  • change the water in the tank daily;
  • add 3% hydrogen peroxide to the heater-cooler device’s water tank to prevent microbial growth and to avoid biofilm build-up; and”
  • disinfect the device weekly to prevent mycobacterial growth.

Sorin emphasized in this notice the importance of users adhering to the manufacturer’s “new” and “updated” set of cleaning and disinfection procedures for its heater-cooler devices.

(Whether these procedures are sufficiently feasibility for hospital staffers to understand and perform reliably, meticulously and consistently to prevent bacterial growth inside heater-cooler devices is a reasonable question to ask.)

I first wrote about the importance of monitoring water over a decade ago in a peer-reviewed medical journal.

According to the York Dispatch, Wellspan York Hospital has confirmed receiving this second 2015 alert.

Cleaning protocols don’t “align” with manufacturer’s instructions

According to The York Dispatch, an internal review by hospital officials found that Wellspan York’s protocols for disinfecting the heater-cooler device “did not align with” the manufacturer’s original instructions.

Namely, the hospital acknowledges that it did not periodically disinfect the heater-cooler device — including its pump, heating and cooling tanks, fittings and all interconnecting tubing — using bleach.

An on-line manual for the Sorin Heater-Cooler System 3T (reference code: Version 02/2015 – CP_IFU_16-XX-XX_USA_014), along with this device’ picture, instructs users to perform the following bleach disinfecting step:

  • “Prior to operating the heater-cooler for the first time, when placing the system in storage and during regular operation, the (heater-cooler device’s) water circuits must be disinfected at intervals of 14 days. … (U)se Clorox Regular Bleach (active ingredient: 8.25% sodium hypochlorite)” or another type of approved disinfectant.

Whether the complexity of executing the device’s disinfection and maintenance procedures might explain, in part, why the hospital did not perform them is unclear.

A heater-cooler device recall

One month after releasing its safety field notice, The Sorin Group issued a class 2 recall of its Stockert Heater-Cooler System 3T on July 15, 2015.

The recall advises customers to properly maintain the heater-cooler device and strictly adhere to the manufacturer’s “new” instructions for use, which, according to the recall, were provided in Sorin’s “Field Safety Notice,” dated June 15, 2015.

This is a worldwide recall impacting 1,755 devices.

(According to this “Field Safety Notice,” its “Attachment 1” provides the company’s “new” instructions for cleaning and disinfecting the heater-cooler. But, I could not identify a page in the notice labeled “Attachment 1” — only pages labeled “Attachment 2” and “Attachment 3.”)

FDA, CDC alerts

Four months later, on October 15, 2015, the FDA issued a safety communication that, for the first time, publicized the risk of heater-cooler devices infecting patients with mycobacteria during cardiothoracic surgeries.

Two weeks after that, on October 27, 2015, the CDC published a similar notice, in part, to “raise awareness among health departments, healthcare facilities, and healthcare providers of the possible association between (mycobacterial) infections and use of heater-cooler devices.”

Recommendations to prevent infection

Both the CDC and FDA’s safety notices — along with Sorin’s “Field Safety Notice“(2015), “Important Information” alert (2014), and recall notice (2015)  — provide important information and advice for U.S. hospitals to prevent patient infections due to a heater-cooler devices contaminated with mycobacteria.

For example, the FDA now advises hospitals to use only sterile water or water that has been passed through a filter of less than or equal to 0.22 microns — not tap water — to rinse, fill, refill or top-off the water tanks in heater-cooler devices, because tap water can contain mycobacteria and cause infections if introduced into the sterile field.

The FDA also recommends that hospitals “use only sterile water or water that has been passed through a filter of less than or equal to 0.22 microns” when preparing ice for cooling patients during surgical procedures.

Readers are advised, too, to review the recommendations I provide in my 2014 article discussing the deadly outbreak at Greenville Memorial Hospital, as well as to read the European study published in Clinical Infectious Diseases, in July 2015, which warns about the risk of infections from aerosolized mycobacteria escaping from heater-cooler devices.

Lessons learned?

This article’s timeline of events suggests that Wellspan York Hospital’s deadly outbreak in 2015 might have been avoided, possibly, if U.S. officials had publicized sooner and more proactively the potential for heater-cooler devices filled with tap water to infect patients with mycobacteria.

To be certain, the risk of infection associated with the use of tap water in operating rooms has been known for decades.

But if a lesson can be learned from Greenville Memorial’s outbreak identified over a year earlier in June 2014, it may be that erring on the side of caution by publicizing evidence-based concerns about a device’s risks, both promptly and proactively, might forestall future deadly outbreaks.

Article by: Lawrence F Muscarella, PhD; posted: 11-5-2015; updated: 02-08-2017, Rev A.

Lawrence F Muscarella, PhD, is the president of LFM Healthcare Solutions, LLC, a solution-oriented company with the objective to improve healthcare safety through evidence-based consultations. Click here for more details.

Email:; Twitter: @MuskiePhD

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