Greenville Health System will expand a new water filtration system to all of its campuses to prevent another outbreak like the one that infected 15 patients and may have contributed to the deaths of four of them.
Officials have linked the infection, Mycobacterium abscessus, to tap water at Greenville Memorial Hospital.
“The fact that it is in the tap water, we feel our responsibility is to just take the extensive steps to protect the patients once they’re in our environment,” said Dr. Robert Mobley Jr., medical director for quality and patient safety at Greenville Health System.
“We have not screened all those hospitals because once we found it was in the general water,” he added, “it would not change what we do because we duplicate the process for all our hospitals, whether it’s cleaning, sterilization, all that.”
Officials originally thought the source of the infection was a piece of equipment — an ice machine or a cardiac perfusion machine. But a preliminary investigation cleared them both, officials said.
Installing the new filtration system — which screens down to 2 microns, though average bacteria are 8 microns — is an extraordinary measure, Mobley said.
“This is a very unusual thing for organizations to do. It’s not standard by any means,” he said. “But we’ve taken that on so as to protect our patients.”
Mobley said he was aware of one other hospital in the country that installed the filtration system after an outbreak and that it has experienced no subsequent infections.
In the environment
Mycobacterium abscessus is common in the environment, typically found in soil and water, according to the U.S. Centers for Disease Control and Prevention. Healthy people drink it and bathe in it with no problem and officials say it’s safe to use.
State health officials issued a statement earlier this week saying that consuming even high levels of Mycobacterium abscessus isn’t typically a risk for infection.
But it has been known to cause infections in surgical patients, though that’s rare, according to CDC, which investigates about half a dozen cases a year.
GHS said the patients who were infected suffered from some serious underlying health conditions that could have made them more susceptible. Mobley said he couldn’t divulge the nature of those conditions for confidentiality reasons.
The first infection came to light in March, officials said. While most of the patients had undergone cardiac surgery, two had abdominal surgery and one a neurological operation, officials said.
All the patients who had cardiac surgery were infected at the site of their incisions, he said. Some may have had drainage, or a boil over the incision depending on where they were in the course of the infection, he said. But it’s not uncommon to see some inflammation or reaction after cardiac surgery, he said.
It was the fact that they saw more infections than usual that led them to perform the additional cultures that identified the mycobacterium, he said. That and the fact that the infections occurred so long after the surgery.
Mycobacterium has a long incubation period. It was 79 days in the average patient infected at GHS, officials said.
“Typically, if a patient has a sternal wound infection, it’s a closer proximity to time of the surgery,” Mobley said. “The time period was of concern.”
The hospital’s infection rate for heart surgery is 35 percent below the expected range, and it’s 45 percent below the expected range for surgery overall, he said.
The actual source of the infections may never be known, Mobley said. But he said previously that although sterile water is used on or near the patient, it’s possible pre-surgery hand washing may have contributed.
During the investigation, which looked at common elements between the patients, he said, in addition to the machines used in the surgeries, officials checked the operating room where they were performed and found the mycobacterium in the tap water after culturing the scrub sinks and other plumbing.
Subsequently, he said, they did an extensive cleaning of the OR, including the air handling system, before taking new cultures, which showed the bacteria were eradicated. Surrounding ORs serviced by a water system in the same corridor also were extensively cleaned, he said.
But because tap water comes into other ORs too, they were checked and no bacteria were found, he said.
Nonetheless, along with the new filtration system, the hospital is now also screening for the mycobacterium in addition to standard bacteria, he said.
Though a fifth patient was rumored to have died, Mobley said that wasn’t true.
“We heard that, too,” he said. “But we went back and checked with all our patients and there have been no more deaths. We’ve only had four deaths of the original 15 patients, and 11 people are still alive.”
No other infected patients or areas have been identified since June 1, according to officials, but GHS will continue to monitor the situation for four months.
GHS was following standard procedure prior to the infection, Mobley said. The steps taken since aren’t required.
“We felt it was our obligation to use every method we could to protect our patients,” he said. “The measures we’ve taken will make us an even better, safer place.”