Case 3: Nosocomial infections and Surveillance/Outbreak Investigations

Upon reviewing the monthly statistics for C.difficile in your facility you note that there are seven cases of C.difficile associated disease (CDAD) on the gastrointestinal surgery floor in the past three weeks. You decide to investigate further and find that these are, indeed, laboratory confirmed cases and that all of them have been acquired in-hospital The number of cases is above the usual baseline for this ward.
Case Three Questions:
1. Describe the steps you would take to immediately investigate and control this outbreak.

“Epidemic associated infections often are clustered temporary or geographically suggesting that infections are from a common source (e.g. contaminated equipment or devices), …secondary to person-person transmission” (Lautenbach p. 143). With this in mind my immediate steps to control the outbreak would be to:

steps to control the outbreak
Step1. ensure all patients with confirmed cases of C.Difficile are on contact isolation precautions and those with suspected C. Difficile are tested (c.diff tool kit PDF) .

Step 2. I would implement a gastrointestinal illness algorithm “to immediately identify and implement Contact Precautions for patients with acute onset diarrhea” (c.diff tool kit PDF) and ensure stool samples are tested for this patient group and that contact precautions remain in place for the duration of diarrhea, then 48-72hrs after stools normalize(c.diff tool kit, p.8).

Step 3. Implement “A transmission risk assessment of each patient” (c.diff tool kit, p.8) to determine if further precautions required.
Step 4. Implement an infection control sheet for documentation in the chart that indicates when precautions are initiated and when they are discontinued along with a stool chart.

Step 4. Provide ongoing staff, patient and visitor education re: hand hygiene and infection prevention precautions

Patients with C.diff should be in a single room when possible, in shared room with other c.diff patients (each under contact precautions with their own personal commodes or if that is not possible, ensure the contact precautions in place for the patient’s bed space and immediate surroundings. ( c.diff tool kit PDF).

Special note: Deciding whether or not to close the gastrointestinal surgery floor would be based on “the severity of the illness, the size of the outbreak and the rate at which new cases are occurring” (Lautenbach p. 149). Deciding whether to limit new admissions to the floor would occur in consult “with the MHO, or designate for the management of outbreaks by IPC and the facility administrator is required under the public health act” (c.diff tool kit PDF)

I would then contact the lab to save all specimen “isolates that might be part of the outbreak” for C. diff strain comparison and outbreak source tracing (Lautenbach p. 145).

Steps to investigate the outbreak
The immediate steps I would take to investigate the outbreak would be to

Step1. test all patients on the unit and test rooms that had contained a C.diff treated patient after discharge and before new admission to ensure that current sterilization/cleaning measures are adequate so that the room and surfaces within it are not C.diff reservoirs.

Step2. Continue trace infection source or reservoir. Consider the OR if needed and lab test the OR and surgical equipment to ensure the equipment or OR itself is not the disease vector for transmitting the C. difficile. “Contamination of environmental surfaces along with lapses in infection control precautions…have been implicated repeatedly in outbreaks of…C.difficile” (Lautenbach p. 145).

Step3. Implement cleaning schedule and review cleaning practices such as the use of sporicidal cleaning agents. Ensure surfaces frequently touched by patients are cleaned twice daily (c.diff PDF, p8)

Step 4. Implement a discharge/transfer cleaning audit too.

In the event that the outbreak is traced back to a single patient, following up with public health may help prevent the spread in community. In the event the outbreak is traced back to equipment (surgical equipment not being able to be effectively sterilized), following up with the manufacturer may help prevent similar outbreaks in other institutions using the same devices.

Special note: Conducting an epidemiologic study would be a step (being mindful of resources) if there is “need to convince clinical staff that the proposed source or mechanism (of disease spread) suggested by chart reviews and observations is correct” and lab testing was unable to trace outbreak back to source.
2. Provide a case definition for this outbreak and provide the rationale for your answer.

A case definition states which individuals have symptoms or findings and specifies the time period: the time the symptoms began, were recognized and specifies the location associated with the onset of symptoms (lautenbach, p146). In this case the case definitions includes the seven patients on the gastrointestinal surgery floor who have laboratory confirmed cases of C. difficle over the last three week period. Our case definition is based on the laboratory confirmed data however this case definition may widen or narrow depending on the results of the investigation and the discovery of the final source of infection (infection reservoir). “How broad or narrow to make the case definition often depends on the frequency with which the organism or condition is encountered”(Lautenbach, p.146). At present our case definition has not expanded outside the GI surgery floor’s 7 confirmed cases

3. Staff are concerned about their risk for acquiring C.difficile. What is your response?

Staff should place C. diff infected patients on contact precautions to prevent transmission. Staff should glove and gown upon entering infected patients’ rooms or patient area. (PICNet, 2012).

Staff should follow good hand hygiene practices before and after patient contact. Soap and water is more effective than alcohol base handrub against C. Diff (Picnet, 2012, p. 6).

Staff should maintain patients on contact preautions for 48-72 hours after stools normalize (Picnet, 2012, p. 7)

Few staff will have risk factors for acquiring C. Diff. Risk factors for C. Diff are:

  • age over 65 years
  • prior hospitalizations
  • increased length of stay in an intensive care unit, ICU
  • nonsurgical admission to the hospital
  • exposure to broad spectrum antimicrobials
  • longer duration of antimicrobial use
  • exposure to multiple antimicrobials
  • exposure to acid supressive therapy
  • cancer chemotherapy
  • renal insufficiency
  • hemodialysis
  • nasogastric tube in-situ

4. Staff are also concerned that alcohol handrub may not be adequate. What is your reply?

Alcohol based hand rubs do not kill C. diff spores so hand washing with soap and water is necessary. (Lautenbach, p.224).
5. You decide to implement a system for monitoring the quality of cleaning. What types of monitoring might you consider and why? What are some of the newer adjunctive technologies to cleaning and disinfection of surfaces and equipment.

  • Develop a schedule to regularly review and evaluate all cleaning practices by an individual external to the unit. (PicNET, 2012, p.7 ).
  • Use sporicidal agents to address environmental contamination in areas associated with increased rates of CDI such as Sodium hypochlorite 1000 ppm – 5000 ppm and Hydrogen peroxide enhanced action formulation (PicNET, 2012, p.7)
  • UV light
  • Physical cleaning of surfaces is required in order to reduce the bioburden.
  • ensure pre-cleaning to reduce bioburden occurs before sporocidal cleaning
  • Insigate twice daily cleaning of frequently touched surfaces in the patient’s bed space and bathroom (Picnet, 2012, p8)
  • put in place a discharge/transfer cleaning audit tool for room cleaning when the patient is removed from Contact Precautions as well as upon transfer/discharge.


1. Lautenbach, E., Woeltje, K., and Malani, P. 2010. Practical HealthcareEpidemiology, 3rd ed.

2.  Provincial Infection Control Network of British Columbia: PICNet BC Clostridium difficile infection toolkit and clinical management algorithm at


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