Transcript Document

Salmonella Oranienburg Infections
associated with Fruit Salad Served in
Healthcare Settings—Northeastern
United States, June-July 2006
Beth Daly, MPH
Communicable Disease Epidemiologist
Communicable Disease Surveillance Section
NH Department of Health and Human Services
Division of Public Health Services
Salmonellosis
• US: >30,000 infections reported each year
• NH: 2nd most common bacterial foodborne
illness with 150-200 cases each year
• >2500 different serotypes
• Poultry and cattle serve as reservoirs
• Source of outbreaks include meat, produce,
ill food service workers, etc.
• Primarily diarrheal illness
• Illness lasts 2-5 days
• Incubation period 6-72 hours
NH Department of Health and Human Services
Division of Public Health Services
Salmonella Oranienburg
• 13th most common serotype of Salmonella
reported to CDC
– 495 cases reported in 2004 (1.4%)
• 9 outbreaks reported to CDC since 1996
• Outbreaks associated with meats and produce
– Ground beef, chicken, pizza, mango
NH Department of Health and Human Services
Division of Public Health Services
Salmonella Surveillance
• Mandated reporting of salmonellosis in NH
• Reports received from HCP, ICP, laboratories
• For each case reported there are an estimated
38 cases that go unreported
NH Department of Health and Human Services
Division of Public Health Services
NH Department of Health and Human Services
Division of Public Health Services
Pulsed Field Gel Electrophoresis
• Isolated bacteria from each case used
• DNA from the bacteria is restricted by an
enzyme and undergoes electophoresis to
produce a pattern or DNA fingerprint
• Patterns compared to determine if isolated
organisms are different, similar, or
indistinguishable
• Two-enzyme approach used
NH Department of Health and Human Services
Division of Public Health Services
PFGE Analysis
NH Department of Health and Human Services
Division of Public Health Services
Use of PFGE in Surveillance
• NH PHL performs PFGE on all isolates of:
– Campylobacter
– Salmonella
– Shigella
– Listeria
– E. coli O157:H7
• These patterns are entered into a national and
state database to look for “matches”
• This allows for recognize of local and multistate outbreaks
NH Department of Health and Human Services
Division of Public Health Services
Nosocomial Salmonellosis
• Uncommon in developed countries
• Healthcare facilities (HCF) don’t test for
salmonellosis in patients hospitalized >72
hours with diarrhea
– C. diff the most common cause of hospital
acquired diarrhea
• Since 1960, 56 outbreaks have been described
– Most often associated with food, feed, visitors, staff
– 9 occurred in the US, most recent in 2002 and 1996
NH Department of Health and Human Services
Division of Public Health Services
NH Outbreak
• July 19th: NH DHHS investigated a
salmonellosis outbreak at a local hospital
• Initially 5 cases identified
– 2 patients, 2 HCP, 1 cafeteria patron
• 3 of 5 cases determined to be S. Oranienburg
• Concerns about medical devices, ill HCP, or ill
FSW
• Challenging disease control approach
NH Department of Health and Human Services
Division of Public Health Services
Immediate Infection Control
• Active surveillance and exclusion among
staff in affected units
– Shift change sign-in
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•
•
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Mandatory in-service training to staff
Alert hospital-wide email
Inspection of hospital kitchen
Routine salmonellosis testing for patients
with diarrhea
NH Department of Health and Human Services
Division of Public Health Services
Multistate Outbreak Recognition
• July 19th: NH DHHS and MHD investigated
outbreak of S. Oranienburg at local hospital
• July 21st: MA DPH reported S. Oranienburg
cases at local LTCF
• NH cases and other northeastern states
report cases with the same PFGE pattern as
MA cases
• Xbal pattern uncommon and seen only 14
times prior to this cluster
• BlnI pattern not seen before
NH Department of Health and Human Services
Division of Public Health Services
Frequency of BlnI Patterns in S. Oranienburg
with the Xbal JJXX01.0056 Pattern, 1998-2006
Unknown
JJXA26.0005
JJXA26.0017
60
50
40
30
20
10
0
1998
1999
2000
2001
2002
2003
2004
2005
NH Department of Health and Human Services
Division of Public Health Services
2006
Methods- Case Finding
• Case Definition: culture-confirmed cases of S.
Oranienburg with
– Illness onset after June 1st
– Xbal pattern JJXX01.0056 and Blnl pattern
JJA26.0017 if available
• PulseNet queried weekly
• Announcements on listserves: foodborne
outbreaks, promed mail, SHEA, APIC, EIN
• Active case finding in affected facilities
NH Department of Health and Human Services
Division of Public Health Services
Methods- Hypothesis Generation
• Routine surveillance questionnaires reviewed
• Extended questionnaires administered to
small subset of cases
– 300 exposures including 234 food items
• Facilities with cases surveyed to determine
brand and distributor information for fruit
salad served in the facility
• 26 unaffected facilities in NH surveyed for
comparison
NH Department of Health and Human Services
Division of Public Health Services
Methods- Case Control Study
• Case control study conducted between
August 15th and September 6th
• Cases were eligible if
– Onset between June 15th and July 31st
– Experienced diarrhea
– Two enzyme match
– Could be interviewed
• Control selection was based on type of case
and eligible if
– No diarrhea since June 1st
– Must be on a solid diet
NH Department of Health and Human Services
Division of Public Health Services
Control Selection
• Patients exposed in HCF
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–
–
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7 day period before onset calculated
Dates of hospitalization during these 7 days
List of patients hospitalized on same days created
List randomized and selected until 3 controls found
• Healthcare Employees
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–
–
–
7 day period before onset calculated
Dates case worked during these 7 days
List of coworkers on same days created
List randomized and selected until 3 controls found
• Community Cases
– List of neighbors generated using reverse phone
– Closest neighbors called until 3 controls found
NH Department of Health and Human Services
Division of Public Health Services
Results- Geographic Distribution
• 42 cases in 10 states
and Canada:
MA (12)
NH (10)
NY (4)
PA (3)
VT (3)
Canada (2)
KY (2)
MD (2)
ME (2)
CT (1)
NJ (1)
NH Department of Health and Human Services
Division of Public Health Services
Results- Case Details
• Age: 8 months to 96 years (median=59)
31% over age 70
• Sex: 28 females (67%)
• Healthcare Relationship:
– 21 hospitalized patients or LTCF residents
– 9 healthcare employees
– 1 case who ate in hospital cafeteria
• Illness onset dates ranged from June 15th to
July 25th
NH Department of Health and Human Services
Division of Public Health Services
6/15/06
6/17/06
6/19/06
6/21/06
6/23/06
6/25/06
6/27/06
6/29/06
7/1/06
7/3/06
7/5/06
7/7/06
7/9/06
7/11/06
7/13/06
7/15/06
7/17/06
7/19/06
7/21/06
7/23/06
7/25/06
7/27/06
7/29/06
7/31/06
Number of Cases
Culture Confirmed Cases of Salmonella
Oranienburg by Date of Onset (n=22)
4
3
2
1
0
Date of Onset
NH Department of Health and Human Services
Division of Public Health Services
Results- Hypothesis Generation
• Interviews showed a high proportion of cases
consumed fruit salad in healthcare facilities
– 23 of 33 cases (70%) consumed fruit salad
– 19 of 23 consumed Brand X fruit in a HCF
• 10 (91%) of 11 facilities with cases served Brand X
fruit salad from Ontario, Canada
– Cantaloupe and honeydew melon
• 3 (15%) of 20 control facilities served Brand X
(OR=57, p-value=0.0005)
NH Department of Health and Human Services
Division of Public Health Services
Results- Case Control Study
• Illness significantly associated with fruit salad
consumption
– Any Fruit Salad= OR: 8.9, 95% CI: 2.3 - 35.5
– Fruit Salad in a HCF= OR: 6.0, 95% CI: 1.5 - 23.5
• Many fruit salad components also significant
• Significant correlations between many
individual components
• Multivariate analysis not feasible
• Specific component not statistically implicated
NH Department of Health and Human Services
Division of Public Health Services
Results- Matched Univariate
Food Item
Cases
(n=21)
Controls
(n=33)
Matched
OR
95% CI
N
%
N
%
Any Fruit Salad
14/20
70%
4/30
13%
8.9
2.3-35.5
Fruit Salad in a
Healthcare Facility
12/20
60%
4/30
13%
6.0
1.5-23.5
Cantaloupe in Fruit Salad
12/20
60%
2/30
7%
9.9
2.2-44.5
Honeydew in Fruit Salad
11/20
55%
1/30
3%
16.9
2.4-119.6
Watermelon in Fruit Salad
9/19
47%
2/30
7%
6.9
1.4-33.7
Pineapple in Fruit Salad
8/19
42%
1/29
4%
40.6
3.0-548.4
Red Grapes in Fruit Salad
7/20
35%
0/30
0%
9.8*
1.5-65.6
*Uses a 0.5 continuity correction
NH Department of Health and Human Services
Division of Public Health Services
Traceback and Product Investigation
• Several recent outbreaks of Salmonella
associated with cantaloupe and honeydew
– > 25 since 1984, 16 since 1998
– 1998 outbreak of S. Oranienburg in Ontario
Canada associated with cantaloupe
• FDA and CFIA conducted traceback and
traceforward investigations on August 24th
• Brand X Canadian facility inspected
• Cantaloupe and honeydew from California
• Unable to traceback to farm due to large
number of supplying brokers
NH Department of Health and Human Services
Division of Public Health Services
Challenges
• Affected population
– Other significant medical issues
– Age
– Mental status
• Distinguishing between primary and
secondary cases
• Infection control
• Identification of the source within the fruit
salad components
NH Department of Health and Human Services
Division of Public Health Services
Conclusions
• Interventions on farm may prevent produceassociated outbreaks
• Nosocomial salmonellosis rare in US
– Recognition is difficult due to stool testing
practices in hospitals
– May be difficult to distinguish between
primary and secondary cases
– Foodborne outbreaks in healthcare settings
can cause significant illness, costs, fear
NH Department of Health and Human Services
Division of Public Health Services
Acknowledgements
• Hospital ICP
• NH Disease Control and Laboratory Staff
• Collaborating States:
MA, NY, PA, VT, KY, MD, ME, CT, NJ
• CDC:
Dr. Christine Olson, MD, MPH, EISO
Dr. Michael Lynch, MD, MPH
NH Department of Health and Human Services
Division of Public Health Services