Hospital Outbreaks

Allison McGeer

Mount Sinai Hospital

416-586-3118

amcgeer@mtsinai.on.ca

Outbreaks

• Anything out of the ordinary

• An increase in the occurrence of a complication or disease above the background rate

• A statistically significant increase in the incidence of an infection

Why are hospitals a problem?PATHOGENS

– They concentrate virulent pathogens

ACCESS– By hands on care, they allow transmission of these

pathogens– By devices & parenteral therapy, they permit access

HOSTS– They admit susceptible hosts (elderly,

immunocompromised)– They make them more susceptible (chemotherapy, surgery)

Hospital Outbreaks

• 1 in 8 patients in Canadian hospitals acquire an infection as a result of their hospital stay– 5-10% of these are part of outbreaks

• Rate: 1/10,000 admissions (Wenzel, 1981) 1/12,000 admissions (Haley, 1985)

at least an equal number of “clusters”

Outbreaks to be prepared for:

• MRSA/VRE; S. aureus (nurseries); S. pneumoniae; GAS

• P. aeruginosa, Serratia, Salmonella; resistant gram negs (ICU)

• Legionella, Mycobacteria, C. difficile

• Scabies

• Candida, Aspergillus

• Influenza, Hepatitis A/B/C, SREV, Adeno

Outbreaks to be prepared for:• MRSA/VRE; S. aureus (nurseries); S.

pneumoniae; GAS• P. aeruginosa, Serratia, Salmonella;

resistant gram negs (ICU)• Legionella, Mycobacteria, C. difficile• Scabies• Candida, Aspergillus • Influenza, Hepatitis A/B/C, SREV, AdenoPEOPLE ARE THE RESERVOIR

TRANSMISSION FROM PERSON TO PERSON IS

THE PROBLEM

“Other” hospital outbreaks• E. coli O157:H7 in a salad served to patients, and

in cafeteria• Legionella pneumophila in water supply• Pseudomonas aeruginosa from water/sinks• Ralstonia picketii from contaminated normal

saline• Aspergillus fumigatus from an air conditioner• Serratia marcescens blood infections from

propofol• Candida spp. from vacuum seals in equipment for

preparation of TPN

Hospital vs. Community Outbreaks

• Reservoir/propagation– Reservoir is people (usually patients)– Propagation is person to person

• We provide medical care to patients, as well as outbreak management– Easier to get medical/laboratory information– Differences between goals more evident

Preparing for outbreaks - Prevention

• Physical structure• Private rooms• Adequate space – between patients, for cleaning• Adequate ventilation• Enough handwashing sinks, well-placed

• Design in purchased equipment• Glucometers• Needleless IV systems• Monitors for negative pressure rooms• Machines for cleaning/disinfecting endoscopes/ endoscopes

themselves• Cleaning/disinfection/sterilization

• Adequate policies• Adherence to policies

Preparing for outbreaks - Prevention

• Handwashing– Accessibility– Programs for compliance

• Education– Aseptic technique– Handwashing– Isolation precautions– Surveillance/reporting

Preparing for outbreaks

• Detection– surveillance, awareness– culture, lab processing protocols– thresholds, time frames

• Preservation of samples/isolates (typing)

Preparing for outbreaks

• Lines of communication– awareness among administrative staff– media relations

• Funding– microbiology lab services

• Policies for outbreak management

Goals of outbreak investigation/management

Outbreak types

• Cause unknown

• Control uncertain

• Disease severe/many cases

• Something to learn

• Cause is known• Exposure/transmission known• Control measures effective• Small number/non-severe cases• “Nothing to learn”

ManagementInvestigation

Outbreak investigation• Verify diagnosis • Confirm the outbreak• Develop a case definition• Obtain descriptive epidemiology• Develop a hypothesis• Test the hypothesis• Refine hypothesis/additional studies• Implement control and prevention measures• Communicate findings

Hospital outbreak investigation• Verify diagnosis• Confirm outbreak• Perform literature review/call experts• Develop a case definition• Obtain descriptive epidemiology• Open lines of communication• Implement control measures• Consider definitive investigation

Initial Investigation

1 Verify diagnosis

2 Confirm the existence of a problem- confirm the diagnosis

- review existing data (surveillance records, interviews, microbiology records, charts)

3 Perform a literature review/ call experts - reservoirs, mode of transmission

- things that went wrong

Initial Investigation4 Develop a case definition

- microbiology- other lab, radiology - clinical signs/symptoms- other (e.g. skin testing for TB)- set time/place parameters

5 Identify, count, describe cases - line listing- time/place person- describe nature and severity- plot epidemic curve

Initial Investigation

6 Open lines of communication- consider media strategy- ensure all isolates/potential isolates are saved

7 Implement control measures- enforce existing measures- supplement

Initial Investigation

8 Consider definitive investigation- formulate hypotheses- case control/cohort studies- cluster analysis

Problem #1

• 3 candidemias on 14th level at MSH in one month

• 14th level is gi medicine/general surgery – 68 beds– large oncology/IBD population– 25 pts per month on TPN

Problem #2

Invasive GAS disease, LTCFs

0

5

10

15

20

25

30

92 93 94 95 96 97 98 99 2000

Year

Nu

mbe

r o

f cas

es

Other presentations/articles

• http://www.idready.org/slides/03outbreak-slides.pdf

• http://www.dsf.health.state.pa.us/health/lib/health/Outbreak_Investigation.ppt

• http://www.wvdhhr.org/idep/PPTs/OutbreakInvestigation.ppt

• http://www.cdc.gov/ncidod/eid/vol4no1/reingold.htm