Greenville hospital officials say a fourth patient has now died after testing positive for a rare mycobacterial infection they may have contracted during surgery this year.
Greenville Health System officials on Monday released the preliminary findings of a three-month investigation into 15 infections at the hospital that were discovered in May. Investigators said they could not identify one specific process or piece of equipment that triggered the outbreak, but they think the Mycobacterium abscessus organism originated in a filtered ice machine that was used to cool patients’ blood during cardiac surgeries.
“We now believe that surgery processes involving the use of tap water may have inadvertently brought the organism into the perioperative environment,” GHS medical director of quality Robert Mobley Jr., said in a statement. “Although we use sterile water in or near the surgical sterile field, even something as seemingly safe as pre-surgery hand washing may have contributed.”
GHS says the infections are caused by an atypical mycobacterium, which is found naturally. Mobley said infections from the organism are typically rare and victims usually have an underlying medical condition. He said there are no specific symptoms that can identify an infection, but notes it is not contagious.
Hospital officials also said on Monday that a fourth patient had died, although they did not say when the death occurred. The hospital previously said last month that three patients with the infection had died, although they could not confirm if the infections were a contributing factor. Two other patients are still hospitalized.
Mycobacterium abscessus is normally found in soil and water around the United States and does not cause infections in normal, healthy individuals. It rarely causes surgical site infection, according to medical health regulators.
“The overwhelming majority of surgical patients treated at Greenville Memorial have not been affected by this rare mycobacterial infection, and we apologize for any concern that we may have caused among our patients or in the broader community,” Mobley said. “The infection has been associated with only a few specific types of invasive surgery. But we believe in transparency and thought it was important to notify the community about the infection out of extreme precaution to ensure their safety and to alert them about possible symptoms.”
Hospital officials said this was the first time they had seen an outbreak of surgical site infections involving mycobacterium. The bacterium is harmless in most circumstances, but can cause infections if it comes into contact with surgical patients whose immune systems have been weakened or compromised.
Greenville Health System said it will now install what may be the state’s first bacteriologic point-of-use water filters in a hospital operating room setting in the wake of a surgical infection that affected 15 patients. Other measures include eliminating slow-flow areas of internal water pipes, flushing scrub sinks for 10 minutes in the morning before first use and strengthening a machine’s manufacturer-recommended disinfectant schedule.
The state Department of Health and Environmental Control has given the hospital its own recommendations to put more safeguards in place for reusing water, including new bacteriologic filters and point of use filters at the sinks.
The Centers for Disease Control and Prevention (CDC) said similar investigations elsewhere have not identified a specific source of such mycobacterial infections. There are no national standards of care about whether hospitals should screen for this bacterium or how they should treat tap water inside the facility. Exposure pathways of potential concern also include inhalation and entry of organisms through abraded skin, according to the Environmental Protection Agency.
EPA regulations do not require that the mycobacterium be eradicated from water because it is not thought to be harmful to the general public under normal circumstances. The environmental bacteria are considered widespread and part of the natural flora of potable water in the U.S.