Risk Factors for Klebsiella infections among hospitalized patients with Pre-Existing Colonization

Abstract Background Klebsiella commonly colonizes the intestinal tract of hospitalized patients and is a leading cause of healthcare-associated infections. Colonization is associated with subsequent infection, but the factors determining this progression are unclear. Methods Intensive care and hematology/oncology patients were screened for Klebsiella colonization by rectal swab culture and monitored for infection for 90 days after a positive swab. Electronic medical records were analyzed for patient factors associated with subsequent infection, and variables of potential significance in bivariable analysis were used to build a final multivariable model. Concordance between colonizing and infecting isolates was assessed by wzi capsular gene sequencing. Results Among 2087 hospital encounters from 1978 colonized patients, 90 cases of infection (4.3%) were identified. Mean time to infection was 20.6 ±24.69 (range 0-91, median 11.5) days. Of 86 typed cases, 68 unique wzi types were identified and 69 cases (80.2%) were colonized with an isolate of the same type prior to infection. Based on multivariable modeling, overall comorbidities, depression and low albumin level at the time of rectal swab were independently associated with subsequent Klebsiella infection. Conclusions Despite the high diversity of colonizing strains of Klebsiella, there is high concordance with subsequent infecting isolates and progression to infection is relatively quick. Readily accessible data from the medical record could be used by clinicians to identify colonized patients at increased risk of subsequent Klebsiella infection. Importance Klebsiella is a leading cause of healthcare-associated infections. Patients who are intestinally colonized with Klebsiella are at significantly increased risk of subsequent infection, but only a subset of colonized patients progress to disease. Colonization offers a potential window of opportunity to intervene and prevent these infections, if the patients at greatest risk could be identified. To identify patient factors associated with infection in colonized patients, we studied 1978 colonized patients. We found that patients with a higher burden of underlying disease in general, depression in particular, and low albumin in a blood test were more likely to be a case of infection. However, these variables did not completely predict infection, suggesting that other host and microbial factors may also be important. The average time to infection was 3 weeks, suggesting that there is time to intervene and prevent Klebsiella infections in hospitalized patients.