Analysis of an outbreak of Clostridium difficile infection controlled with enhanced infection control measures.
BACKGROUND
In October 2004, our Clostridium difficile infection (CDI) rate increased (relative risk, 3.51; 95% confidence interval: 2.96-4.16) from a baseline rate of 1.35 per 1000 patient-days. We describe the outbreak, the relationship between antibiotic use and CDI, and the effect of enhanced infection control measures (EICM) on CDI.


METHODS
Rates were calculated as positive C difficile toxin A or B tests among patients with nosocomial diarrhea per 1000 patient-days (duplicates removed). Antibiotic use was calculated as defined daily dose per 1000 patient-days. EICM consisted of (1) placing patients with diarrhea into empiric Contact Precautions, (2) cleaning with a bleach product in areas with CDI patients, and (3) requiring soap and water hand hygiene when caring for CDI patients. CDI rates were analyzed by chi(2) for trend. Time series methodology was used to examine the association between CDI and antibiotic use.


RESULTS
During the outbreak (October 2004-May 2005), we observed 144 excess cases of CDI. The CDI rate decreased after EICM were implemented (P < .0001) and has been maintained for 36 months beyond the outbreak. Multivariate analysis revealed positive associations between CDI rates and cefazolin use (P = .008) and levofloxacin/gatifloxacin use (P = .015).


CONCLUSIONS
Despite an association between some antibiotic use and CDI rates, we achieved sustained control of an outbreak using EICM without formulary changes or new antibiotic control policies. This suggests that patient-to-patient spread may be a more important cause of increased CDI rates.
Salgado
Cassandra D
CD
Department of Medicine, Division of Infectious Diseases, Medical University of South Carolina, 135 Rutledge Avenue, 12th Floor RT, Suite 1204, Charleston, SC 29425, USA. salgado@musc.edu
Mauldin
Patrick D
PD
Fogle
Pamela J
PJ
Bosso
John A
JA
D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001427:Bacterial Toxins / Q000032:analysis; D016360:Clostridioides difficile / Q000302:isolation & purification*; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control*; D004196:Disease Outbreaks; D004363:Drug Utilization / Q000706:statistics & numerical data; D004761:Enterocolitis, Pseudomembranous / Q000453:epidemiology* / Q000517:prevention & control*; D006235:Hand Disinfection / Q000379:methods; D006801:Humans; D017053:Infection Control / Q000379:methods*; D010356:Patient Isolation / Q000379:methods; D012499:Sanitation / Q000379:methods
D000900:Anti-Bacterial Agents; D001427:Bacterial Toxins