Factors Associated with an Outbreak of Clostridium Difficile Infection Among Patients at a Kansas Hospital, November 2013

BACKGROUND: On November 25, 2013, a hospital notified the Kansas Department of Health and Environment of a possible outbreak of Clostridium difficile infection among hospitalized patients. An outbreak investigation was initiated to identify cases, characterize the scope of illnesses and to recommend appropriate prevention and control measures.

METHODS: A retrospective case study was conducted; patients were interviewed using a standardized questionnaire. In addition, records of patient admission, symptoms, procedures, medication history, unit/room movements, laboratory results, and infection control interventions were abstracted for patients diagnosed with hospital-onset of C. difficile from November 4, 2013 to December 23, 2013. Cases were defined according to the Centers for Disease Control and Prevention’s (CDC) National Healthcare Safety Network 2013 case definition of laboratory-identified hospital-onset and community-onset C. difficile infection. Incidence rate comparisons among outbreak cases and background cases (January – October, 2013) and total inpatient-days were performed using a Poisson test.

RESULTS: Eleven patients met the case definition of having hospital-onset C. difficile. Prior to this outbreak, between January and October, 2013, the incidence rate of hospital-onset C. difficile was 4.3 per 10,000 patient-days and community-onset rate was 10.8 per 10,000 patient-days. In November, the hospital experienced significant increases in hospital-onset C. difficile with a rate of 21.6 per 10,000 patient-days (p<0.0001) and community-onset with a rate of 27.3 per 10,000 patient-days (p=0.017).  Risk factors presented are for patients with hospital-onset C. difficile infections that were identified as part of the outbreak. All patients had medical procedures during hospitalization and seven (64%) had gastrointestinal procedures. All patients were prescribed antibiotics during their hospitalization before onset of symptoms. Seven (64%) received broad spectrum cephalosporins, clindamycin, or fluoroquinolones. Eight (73%) were taking proton pump inhibitors. Prior to onset of symptoms, 10 patients (91%) stayed in a unit where a patient with C. difficile stayed within the previous 10 days. These patients developed onset of symptoms within 2 to 9 days (median = 5.5 days) of admission to the unit. Infection prevention staff worked with environmental service staff to implement CDC’s terminal cleaning checklist in these units. The hospital enhanced patient isolation to 48 hours after symptom resolution.

CONCLUSIONS: An increase in patients diagnosed with community-onset C. difficile at the hospital likely contributed to an increase in patients diagnosed with hospital-onset C. difficile. To decrease the risk of transmission, it is recommended that the hospital maintain vigilant adherence to adequate environmental cleaning, improve hand hygiene compliance and implement an antimicrobial stewardship program.