Clinical Scorecard: Asymptomatic carriage may fuel C difficile spread
At a Glance
Category
Detail
Condition
Clostridioides difficile colonization and infection
Key Mechanisms
The study modeled importation and within-unit transmission, including asymptomatic colonization (AC), symptomatic C difficile infection (CDI), environmental contamination, and room connections.
Target Population
Patients admitted to leukemia and hematopoietic cell transplant units
Care Setting
Two leukemia and hematopoietic cell transplant units at a single health care facility
Key Highlights
In 1,000 simulations, 51% of new colonizations were attributed to importation and 49% to within-unit transmission.
Among imported colonizations, 87% involved patients admitted with AC.
Patients with AC were the modeled source of 92% of transmission events resulting in new colonization; CDI contributed relatively little.
The transmission model estimated 3.9 new colonizations per week, compared with 0.9 identified by the observation model.
Source-attribution estimates were weakly constrained by limited testing data, and the study was conducted at one facility.
Guideline-Based Recommendations
Diagnosis
Study surveillance used stool samples and rectal swabs at enrollment and weekly until discharge for C difficile culture and NAAT; clinically indicated toxin enzyme immunoassay testing identified CDI.
Management
The authors stated that interventions targeting AC could reduce CDI by reducing onward transmission from AC or progression from AC to CDI.
Monitoring & Follow-up
Testing identified a minority of acquisition events in the model; the observation model estimated 0.9 new colonizations per week versus 3.9 in the transmission model.
Risks
Most patients modeled as AC did not progress to CDI.
The model's source-attribution estimates had wide ranges because calibration used data from 18 CDI cases and 85 AC cases.
The single-facility setting and incomplete contact-network data limit generalizability; family and visitor transmission was not included.
Patient & Prescribing Data
Of 421 patients admitted during the study period, 384 (91%) consented to testing in two leukemia and hematopoietic cell transplant units.
The article reports no prescribing or drug-treatment data. It notes that most patients modeled as AC did not progress to CDI.
Clinical Best Practices
Interpret modeled transmission estimates in light of the study's limited testing data and single-facility design.
Recognize that the study's testing approach detected fewer acquisition events than the transmission model estimated.
The authors identified colonization, environmental contamination, and cleaning rates as the modeled factors to which new colonizations were most sensitive.
