Wound care equipment linked to Acinetobacter outbreak
Pulsatile lavage equipment culprit behind several hospital infections; importance of strict infection control procedures reinforced.
Tighter rules governing the use of hand-held, high-pressure, water-pumping pulsatile lavage tools to wash and clean wounds should be adopted to improve wound care safety, according to infection control experts at The Johns Hopkins Hospital.
This assertion comes in response to an investigation of an Acinetobacter baumannii outbreak at the hospital during a two-month period in 2003.
Janice Carr; Jana Swenson
The bacterium infected 11 patients and was traced back to the use of pulsatile lavage equipment manufactured by Bard-Davol Inc. Three of these patients required admission to the ICU for sepsis and respiratory distress, according to a release.
In response, staff at Hopkins using the equipment are now required to wear masks, gowns and gloves during procedures. The procedures must also now be performed in private treatment rooms that are fully disinfected in between patients to reduce the risk of cross contamination between patients and hospital staff.
Additionally, the FDA and Bard-Davol Inc. have agreed to change the product’s labeling to include routine infection control procedures.
“Changes at Hopkins and results of the study should change the way this common procedure is performed at other acute-care hospitals and long-term care facilities,” said senior study investigator and hospital epidemiologist Trish Perl, MD.
Investigation begins
According to the study, infection control precautions are not routinely used during the procedure. Likewise, they are not included in pulsatile lavage equipment package labeling.
The study’s lead investigator, Lisa Maragakis, MD, and colleagues sought to investigate the outbreak and test the hypothesis that this equipment was the organism’s mode of transmission.
From Sept. 1 through Oct. 31, 2003, researchers reviewed the medical records of the 11 patients colonized or infected with multidrug-resistant A. baumannii, including the original five cluster patients and six other patients who were identified during the outbreak investigation.
Seven of the participating 11 patients met the case definition for the case-control study and were compared to 28 randomly selected controls with wounds but without A. baumannii.
Culture results from patient samples of blood, sputum, urine and wounds were also reviewed.
Specific isolates of A. baumannii were analyzed using pulsed-field gel electrophoresis to determine and track the spread of the specific strain of the bacterium involved in the outbreak.
Of the five original cluster patients, one was culture positive for a different strain of the bacterium upon admission, indicating that the infection was not picked up at the hospital and removing it from the investigation of hospital-based cases.
Among the remaining four patients, records showed that three had undergone pulsatile lavage treatment.
Subsequent culture testing of the open-space treatment room for performing the procedure showed widespread presence of A. baumannii on the disposable parts of the pulsatile lavage gun, including disposable tubing and suction canister, as well as on cleaned stretchers, the sink and nearby supply shelves.
Outbreak traced
Maragakis and colleagues found that all of the patients had cultures that grew A. baumannii during the outbreak period.
Six of the seven cases (86%) were treated with pulsatile lavage compared with four of the 28 controls (14%).
Investigators traced the infection to the pulsatile lavage tool and determined that the equipment sprayed the potentially dangerous bacteria into the air and onto surfaces in an open treatment room, with other patients nearby.
“These results confirm that pulsatile lavage was a significant risk factor for acquisition of multidrug-resistant A. baumannii,” the researchers concluded in the study.
Patients who had pulsatile lavage treatment were more than 30 times more likely to have infection than patients who were not treated with pulsatile lavage were, according to the release. Prior residence in a long-term care facility was also a significant risk factor, although no one facility was implicated, and it was unclear how this contributed to the outbreak.
“This was true even though staff correctly followed procedures for its use,” said Perl, also an associate professor of medicine and pathology at The Johns Hopkins University School of Medicine.
“Germs were spread when patients and staff came in close contact with each other during procedures and possibly when fewer equipment parts were changed between patients,” she said. “Guidelines for its use also applied only to health care workers, not to patients, prior to the outbreak.”
All other possible risk factors, including mechanical ventilation and administration of antimicrobial agents, were not found to be statistically significant.
Infection control precautions
Further investigation revealed that a change in the pulsatile lavage procedure had occurred two months prior to the outbreak.
As a cost-saving measure, the disposable suction canisters for the guns were replaced daily or when full, rather than between each patient.
“This case study shows the importance of infection control precautions when introducing a new technology or procedure for use in the health care setting,” said Maragakis, a clinical fellow at Hopkins.
“Pulsatile lavage is used for wound care in a variety of settings,” she added. “We want to make sure that those who perform the procedure know about the appropriate infection control precautions to prevent outbreaks of Acinetobacter or other antimicrobial-resistant bacteria, such as Pseudomonas, which is also a growing problem.”
Perl added that antimicrobial resistance affects patient safety because traditional medications are no longer effective in treating such infections.
“To solve the problem, we are increasingly forced to rely on our basic tools of scientific investigation: finding the initial contact point, or source, of infection and putting in place the necessary steps to prevent an outbreak from happening in the first place,” she said.
The specific strain of the bacterium involved in the outbreak has not reappeared, even after 11 months of follow-up testing. – by Tara Grassia
For more information:
- Maragakis LL, Cosgrove SE, Song X, et al. An outbreak of multidrug-resistant Acinetobacter baumannii associated with pulsatile lavage wound treatment. JAMA. 2004;292:3006-3011.
