Superbugs Common in Patients on Mechanical Ventilation

BOSTON — Acinetobacter baumannii and Candida auris were common among patients receiving mechanical ventilation in both acute care hospitals and long-term care facilities, particularly the latter, according to data from the Maryland Multi-Drug Resistant Organism Prevention Collaborative.

Among the 482 patients receiving mechanical ventilation who had samples collected, 30.7% had A. baumannii — 59.5% being carbapenem-resistant A. baumannii, and 6.6% had C. auris, reported Anthony Harris, MD, MPH, of the University of Maryland School of Medicine in Baltimore, during the IDWeek annual meeting.

Of note, patients in long-term care facilities were more likely to be colonized with A. baumannii (relative risk [RR] 7.66, 95% CI 5.11-11.50, P<0.001), carbapenem-resistant A. baumannii (RR 5.48, 95% CI 3.38-8.91, P<0.001), and C. auris (RR 1.97, 95% CI 0.99-3.92, P=0.05) compared with patients in acute care hospitals, according to the findings, which were also published in JAMA.

Nine patients with cultures positive for C. auris were previously unreported to the Maryland Department of Health, Harris noted.

“The preponderance of emerging pathogens found among patients receiving mechanical ventilation in the long-term care setting may represent a particularly high-risk population (e.g., patients who are chronically ill and receiving ventilation for long periods and who are frequently transferred between acute care hospitals and long-term care facilities), or may reflect differences in infection prevention practices between these settings,” the authors wrote.

Belinda Ostrowsky, MD, an infectious disease specialist from New York and co-chair of the late-breaking session where the findings were presented, pointed out that “patients tend to stay in long-term care facilities longer than in acute care facilities, and that might be a factor why the long-term facilities are more likely to have patients who harbor these pathogens.”

A. baumannii and C. auris are both listed by the CDC in the highest category of “urgent” antibiotic-resistant threats due to limited effective antimicrobials. Recent WHO and other public health guidance have stressed the importance of surveillance to identify patients who are colonized with these pathogens.

“Identifying patients with colonization allows for implementation of contact and enhanced barrier precautions, enhanced environmental cleaning, appropriate selection of empirical antibiotics, and other strategies to prevent spread of infection, which is critical due to the limited effective treatment options,” Harris and team wrote. “To our knowledge, no statewide point or period prevalence survey has been performed for C. auris, and only 1 prior statewide survey (2009) has been performed for A. baumannii.”

In his oral presentation, Harris made a plea for additional studies that target long-term care facilities in other states, also noting that “more work needs to be done on pathogen burden decolonization treatments.”

While its known that these pathogens exist in mechanically ventilated patients, “further surveillance is necessary,” Ostrowsky told MedPage Today. “But whether states can perform the type of study done in Maryland is a question. It takes a great deal of coordination and cooperation to do this.”

For this study, the Maryland Multi-Drug Resistant Organism Prevention Collaborative performed a statewide cross-sectional point prevalence of patients receiving mechanical ventilation admitted to 33 acute care hospitals and 18 long-term care facilities from March to June 2023. The survey participation rate was 100%.

Surveillance cultures, including sputum, perianal, arm/leg, and axilla/groin, were obtained from all 482 patients receiving mechanical ventilation. Sputum, perianal, and arm/leg cultures were tested for A. baumannii, and antibiotic susceptibility testing was performed. Axilla/groin cultures were tested by polymerase chain reaction for C. auris.

Harris and team noted that the survey was limited to patients receiving mechanical ventilation, and the prevalence of A. baumannii cannot be generalized to patients in other healthcare settings. In addition, surveillance cultures were obtained from certain specific sites, and by not including other sites known to potentially harbor A. baumannii and C. auris, the colonization rates may have been underestimated.

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