Multicenter study of the impact of community-onset Clostridium difficile infection on surveillance for C. difficile infection.
OBJECTIVE
To evaluate the impact of cases of community-onset, healthcare facility (HCF)-associated Clostridium difficile infection (CDI) on the incidence and outbreak detection of CDI.


METHODS
A retrospective multicenter cohort study.


METHODS
Five university-affiliated, acute care HCFs in the United States.


METHODS
We collected data (including results of C. difficile toxin assays of stool samples) on all of the adult patients admitted to the 5 hospitals during the period from July 1, 2000, through June 30, 2006. CDI cases were classified as HCF-onset if they were diagnosed more than 48 hours after admission or as community-onset, HCF-associated if they were diagnosed within 48 hours after admission and if the patient had recently been discharged from the HCF. Four surveillance definitions were compared: cases of HCF-onset CDI only (hereafter referred to as HCF-onset CDI) and cases of HCF-onset and community-onset, HCF-associated CDI diagnosed within 30, 60, and 90 days after the last discharge from the study hospital (hereafter referred to as 30-day, 60-day, and 90-day CDI, respectively). Monthly CDI rates were compared. Control charts were used to identify potential CDI outbreaks.


RESULTS
The rate of 30-day CDI was significantly higher than the rate of HCF-onset CDI at 2 HCFs (P < .01). The rates of 30-day CDI were not statistically significantly different from the rates of 60-day or 90-day CDI at any HCF. The correlations between each HCF's monthly rates of HCF-onset CDI and 30-day CDI were almost perfect (rho range, 0.94-0.99; P < .001). Overall, 12 time points had a CDI rate that was more than 3 standard deviations above the mean, including 11 time points identified using the definition for HCF-onset CDI and 9 time points identified using the definition for 30-day CDI, with discordant results at 4 time points ((kappa = 0.794; P < .001).


CONCLUSIONS
Tracking cases of both community-onset and HCF-onset, HCF-associated CDI captures significantly more CDI cases, but surveillance of HCF-onset, HCF-associated CDI alone is sufficient to detect an outbreak.
Dubberke
Erik R
ER
Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA. edubberk@im.wustl.edu
Butler
Anne M
AM
Hota
Bala
B
Khan
Yosef M
YM
Mangino
Julie E
JE
Mayer
Jeanmarie
J
Popovich
Kyle J
KJ
Stevenson
Kurt B
KB
Yokoe
Deborah S
DS
McDonald
L Clifford
LC
Jernigan
John
J
Fraser
Victoria J
VJ
D000328:Adult; D016360:Clostridioides difficile / Q000302:isolation & purification*; D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000382:microbiology; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology; D003625:Data Collection / Q000379:methods*; D004196:Disease Outbreaks; D004761:Enterocolitis, Pseudomembranous / Q000453:epidemiology* / Q000382:microbiology; D006785:Hospitals, University / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D018571:Sentinel Surveillance; D014481:United States / Q000453:epidemiology