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Gut microbiota major source of K. pneumoniae infection in ICU patients
Gastrointestinal colonization of Klebsiella pneumoniae was a significant risk factor for subsequent infection among ICU patients, with nearly half of K. pneumoniae infections being caused by patients’ own microbiota, according to study results published in Clinical Infectious Diseases.
Claire L. Gorrie, a PhD student at the University of Melbourne, Australia, and colleagues reported that the findings are of “clinical significance in the ICU setting,” and that routine screening for K. pneumoniae colonization upon admission may reduce the risk for infection in colonized patients and transmission to others.
According to the researchers, previous studies have shown that gastrointestinal (GI) colonization of extended-spectrum beta-lactamase (ESBL) or carbapenemase-producing (CP) K. pneumoniae increase the risk for infection. However, they noted that the majority of health care-associated K. pneumoniae infections are not caused by ESBL or CP, and little is known about the frequency and relevance of general K. pneumoniae colonization. Therefore, Gorrie and colleagues conducted a 1-year, prospective cohort study to better understand the prevalence of colonization and its contribution to infection.
The researchers screened 498 ICU patients for rectal and throat carriage of K. pneumoniae shortly after admission. They used whole genome sequencing to characterize the bacteria and examined epidemiological data to identify potential transmission events.
The estimated rate of K. pneumoniae gastrointestinal carriage was 5.9% (95% CI, 3%-8%) among ICU patients who were admitted directly from the community, and 19% (95% CI, 13.6%-25.7%) among those with recent health care contact. The rate of K. pneumoniae infection among patients with GI colonization upon admission was 16%, which was significantly higher than the 3% rate among those with negative baseline cultures (OR = 6.9; 95% CI, 2.3-19.7).
Genomic data revealed that 49% of all K. pneumoniae infections diagnosed during the study period (n = 49) were associated with K. pneumoniae lineages unique to the individual patient. Additional information on 27 infected patients indicated that 48% had GI colonization at baseline.
During further investigations, the researchers identified five potential chains of intra-hospital K. pneumoniae transmission, representing just 12% of infections.
“This suggests that while measures to reduce cross-contamination between patients are necessary, they are not sufficient to eliminate [K. pneumoniae] infections in hospitalized patients, and measures to minimize the risk of infection with the patients’ own microbiome deserves significant attention,” Gorrie and colleagues wrote. – by Stephanie Viguers
Disclosures: The researchers report no relevant financial disclosures.