Federal health officials say they are focusing on water as the potential source of the bacteria that infected 15 patients at Greenville Memorial Hospital in recent months and which may have contributed to the deaths of three of them.
The infection, atypical Mycobacterium abscessus, is part of the normal environment, in soil and dust, for example, according to the U.S. Centers for Disease Control and Prevention. It’s also often found in water supplies, said CDC epidemiologist Dr. Joe Perz.
“When we hear about surgical site infections involving these organisms, we’re thinking water sources,” Perz told The Greenville News.
“And that’s what we have focused on,” he said. “And any piece of equipment in the surgical environment that could have contact with water has to be looked at very carefully.”
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Hospital officials initially said they believed a piece of equipment in one operating room was the source of the infection. It was removed, along with any other potentially affected equipment and the OR was closed. And subsequently, only sterile water was used in surgical procedures, officials said.
On any given day, about one in 25 hospital patients around the country has at least one infection, according to the CDC.
About 722,000 hospital-acquired infections occurred in 2011 resulting in 75,000 deaths, according to the CDC’s latest report released in May. More than half occurred in patients outside of the intensive care unit.
And these infections cost the nation $45 billion a year in health care dollars, said Lisa McGiffert, director of the Safe Patient Project at Consumers Union, who said the number of infections is likely underestimated because not all hospitals report all infections.
The CDC collects information from hospitals on a variety of infections, including blood stream, urinary tract and surgical site infections, Perz said.
But it doesn’t have hard data on mycobacteria infections because they are not reportable, except for surgical site infections such as those that occurred at Greenville Memorial, and mycobacteria are an uncommon cause of infections, he said.
He estimated that the CDC consults on about half a dozen cases a year of mycobacteria infections, including one last year related to cosmetic surgery that involved 19 people from five states who’d had a procedure in the Dominican Republic.
Most of the patients at Greenville Memorial had undergone cardiac surgery, while two had abdominal surgery and one a neurological operation, officials said.
The first infection was traced back to March, officials said.
Appropriately processed surgical instruments and equipment should undergo sterilization so that it isn’t exposed to unsterile water before it comes into contact with the patient, said Dr. Alice Guh, another CDC epidemiologist. And that process should kill all bacteria as well, she said.
It is also possible for people to have the bacteria on their skin or clothing, Perz said, adding that “there have been investigations where we saw associations with particular health care workers.”
But based on what hospital officials reported to the CDC, they seem to have used good infection control standards, Guh said. So water seems the most likely culprit.
Only sterile water is used on the patient, Guh said. But if the primary source of an infection is believed to be tap water, facility plumbing is checked as part of standard protocol, she said.
Any other possible ways for unsterile water to be introduced to the patient, including hand hygiene, handling of injectables, wound care and use of ice post-operatively for pain and swelling also are investigated, she said. And the investigation, which also includes the state Department of Health and Environmental Control, is continuing.
“We wouldn’t be surprised if we could find these bacteria or similar bacteria in the water supply going to any U.S. hospital,” said Perz.
“Our challenge collectively is to think carefully about the potential pathways by which water from the building service could reach the patient, and in particular the site of their surgery or wound,” he said. “So we’re looking at everything, including handwashing, surgical scrub procedures ... and adequate drying and the like.”
Hospital officials said their investigation included examining two pieces of medical equipment in the OR that each use tap water, a potential source of mycobacteria.
“We are vigorously looking at any route in which water could have come in contact with the surgical field, but would like to stress that all GHS operating rooms have followed national standards of practice on OR sterilization of critical equipment,” officials said in a statement.
The outbreak was suspected in late May and officials began an investigation to try to locate the source, said Dr. Robert Mobley Jr., medical director of quality at Greenville Health System.
While preliminary evidence focused on ice from a filtered-water ice machine that is used to cool stop the heart without damaging heart tissue, he said, it was subsequently ruled out as a potential source. Nonetheless, the machine was removed from use on May 21, he said, adding that additional equipment used for cardiac surgery was also removed as of June 6 as information developed.
Part of the puzzle
While infections have been occurring for several months, conditions that existed six months ago may be different today, Perz said. It’s all part of the puzzle.
“If a hospital has disease bacteria present in the water supply, then you’d have to consider that there could be possible exposure at various points in the facility,” he said. “This manifested as a cluster of surgical site infections. It’s a curious feature there were no other infections elsewhere in the hospital.”
These infections can be hard to diagnose because mycobacteria inherently grow so slowly, Guh said.
“Oftentimes, patients present weeks and months after the initial exposure,” she said. “And the clinician may not be thinking of mycobacterium. It may not be at front of their mind.”
Mycobacteria infections are difficult to treat and may require additional surgeries, Guh said. Treatment, which can last six months to a year, usually consists of a cocktail of antibiotics — intravenous or oral — but depends on the nature and location of the infection, she said.
The way an infection like this contributes to a patient’s death depends on the individual, the severity of his condition, his immune status, the site of the infection and the treatment provided, Guh said.
“If a person is not in a good health status, an infection in and around their heart can be a very significant event and can result in severe morbidity and mortality,” she said. “A lot of infections occur in patients who have been in and out of the hospital and have underlying comorbidities.”