At least a dozen children who underwent cardiac surgery at Children's Hospital in New Orleans this summer have contracted a rare surgical-site infection caused by a type of bacteria commonly found in water, soil and dust, an investigation by the hospital has found.
The hospital described the bacteria, mycobacterium abscessus, as a "highly unusual cause of surgical wound infections," and blamed the outbreak on a piece of operating-room equipment used to regulate the temperature of patients on bypass.
The affected children have been hospitalized, and some are "very close to going home," said John F. Heaton, the hospital's senior vice president and chief medical officer.
Dozens of other potentially affected patients were urged to undergo an evaluation, even as the hospital stressed that the infections are "curable with a combination of antibiotics and surgical care of the incision."
"We were able to jump on this pretty quickly," Heaton said in a telephone interview Monday. "We surveil our patients pretty intensely, and when we had several patients present (symptoms) within a 72-hour period, that set off a red flag right away."
The hospital has set up a 24-hour hotline (504-896-2920) to field questions and requests for appointments, and it reached out by telephone to some 55 young patients who recently underwent heart surgery. The hospital also has replaced a heater-cooler unit believed to have spread the infection.
"This is the first time Children's Hospital has experienced a group of surgical-site infections caused by this bacteria," Heaton wrote in an Aug. 30 letter to patients. "Although we have not reached final conclusions, we are reaching out to the families of all patients possibly affected to alert you of the increased risk of wound infection and to provide care and heightened follow-up care for your child."
Known to contaminate medical devices, mycobacterium abscessus can cause a number of different infections, usually involving the skin, according to the Centers for Disease Control and Prevention. The bacteria are "distantly related to the ones that cause tuberculosis and leprosy," according to the CDC, but generally are treatable with antibiotics and removal of the affected tissue.
The hospital's investigation determined that a "small minority of patients" who underwent surgery at Children's between early June and July "have shown signs or symptoms of problems," which include swelling of the surgical incision, "wound drainage," redness and fever.
Because of the "slow onset and unusual nature of this infection," Heaton wrote, "we are notifying all patients of our concerns and findings."
"We regret that any of our patients could possibly be affected by this infection," he added. "Our thoughts are with those involved, and we apologize for any anxiety caused by this communication."
An investigation by the hospital traced the infections to a heater-cooler unit that Heaton described as commonly used in hospitals and "very difficult to completely disinfect."
He wrote that hospital leaders took "immediate action to address the issue," identifying the cause of the infections and proactively informing patients and "all relevant government agencies," including the Louisiana Office of Public Health and the CDC.
"Our response team has also consulted other hospitals that have dealt with the same issue in the past for guidance and information regarding lessons learned and best practices for treatment," Heaton wrote in the letter to patients. "It is our intention that no patient affected by this situation will incur additional clinical cost for resulting treatment or evaluation."
Kelly Zimmerman, a spokeswoman for the Louisiana Department of Health, described the outbreak as "something we hadn't seen before." She said state health officials made a number of recommendations to the hospital regarding patient notification and evaluation.
"The bacterium is not rare in the environment, but we have not seen very many outbreaks," Zimmerman said. "I don't have an exact number, but we believe there have only been about six cases across the United States in the recent past."
Children's Hospital traced the infections to a single operating room in which the contaminated heater-cooler unit was used. "This room has been terminally disinfected," the hospital said in a statement, "and our ongoing environmental surveillance of the operating rooms has not shown any contamination with the organism beyond the involved device."
The infections are not the first outbreak Children's Hospital has encountered in recent years. The hospital was sharply criticized a few years ago for nearly a half-dozen deaths between August 2008 and July 2009 that were attributed to a flesh-eating fungal infection, mucormycosis, believed to have been spread by contaminated bed linens.
The hospital did not notify affected families of that outbreak until it was revealed in a medical journal years later, and Heaton acknowledged at the time that the hospital could have connected the dots earlier if it had taken a broader view of death cases.
The hospital changed its linen suppliers, disinfected storage areas and began sterilizing linens for high-risk patients following that outbreak.