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Guidelines for Investigating HAI Outbreaks

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Mandatory Outbreak Reporting

Acute care hospitals, long-term acute care hospitals (LTACHs), long-term care facilities (LTCFs), ambulatory surgical centers (ASCs) , freestanding birth centers, outpatient renal dialysis centers, or other defined healthcare facilities (ORS 442.015) are required to report to the local health authority under OAR 333-018-0000, specifically, OAR 333-018-0015; ORS 433.004:

  • Any known or suspected common-source outbreaks, including outbreaks associated with health care, regardless of whether the disease, infection, microorganism, or condition is specified in the reportable disease rule; or
  • Any uncommon illness of potential public health significance.

Local health authorities are empowered to investigate such outbreaks under OAR 333-019-0000, ORS 433.006.

Carbapenem-resistant Enterobacteriaceae is a reportable disease (OAR 333-018-0015; ORS 433.004).

Local health authorities need to report HAI outbreaks, including MDRO outbreaks, to the state communicable disease epidemiology program at 971-673-1111 within 24 hours of receiving an outbreak report.

Basic Definitions

Healthcare-associated infections (HAIs) are caused by a wide variety of bacteria, viruses, and fungi, and are often associated with medical devices and medical procedures. Some of the bacteria are multidrug-resistant organisms (MDRO).

Healthcare-associated MDROs of public health significance include:

Infection: Isolation of an organism, including a MDRO, from a patient specimen with symptoms of infection.

Colonization: Isolation of an organism, including a MDRO, from a patient specimen without symptoms of infection.

Acute care hospitals: Short- and long-term acute care hospitals (LTACHs).

Long-term care facilities: skilled nursing homes (SNFs), nursing homes (NH), assisted living (AL),residential care (RC).

Outbreaks in healthcare facilities:

  • General definitions: an “unusual” number of patients or residents with the same healthcare-associated infection, including MDROs, clustered by time and place.
  • Working definition: two or more patients or residents with a healthcare-associated infection in the same healthcare facility who have matching organism (genus, species), including MDROs, similar exposures, and onset dates within 12 months of each other.

Control Measures

Data Collection and Basic Descriptive Epidemiology

  • Track cases using the Healthcare Associated Infection Case Log (pdf). The log can be completed by hospital or LTCF infection control staff; establishing a single point of contact is recommended.
  • Use tools to get basic descriptive epidemiology, including an epidemic curve (i.e., cases by onset day).
  • Review facility’s microbiology laboratory for other cases of the same organism or MDRO within the last 12 months. If found, perform a limited chart review and note name, date of birth, source, room number, admission source, healthcare facility exposures.
  • Consider performing a patient prevalence survey (pdf) to assess burden of the organism or MDRO in healthcare facility and discuss with ACDP. Refer to the CRE Specimen Collection Protocol (pdf).
  • Monitor the outbreak for new cases for 6 months.
  • If ongoing transmission is identified, discuss performing further investigations  - e.g., environmental prevalence survey (pdf) - with ACDP.



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