A Case for Sherlock:  Outbreak Investigation Strategies

A Case for Sherlock:  Outbreak Investigation StrategiesAn Air Show, Four Countries and an OutbreakAn Air Show, Four Countries and an Outbreak

Baylor University Medical Center

Baylor University Medical Center

Baylor University Medical Center Statistics

Baylor University Medical Center Statistics

37,238 admissions (including newborns) 4,298 babies born 56,570 emergency room visits 254,382 outpatient visits(excluding

home care and emergency department) 1200 licensed beds 1,250 physicians with active privileges 185 medical residents and fellows 5,225 employees

37,238 admissions (including newborns) 4,298 babies born 56,570 emergency room visits 254,382 outpatient visits(excluding

home care and emergency department) 1200 licensed beds 1,250 physicians with active privileges 185 medical residents and fellows 5,225 employees

Test QuestionTest Question

+ =+

Can you determine the correct answer to this question?

Possible AnswersPossible Answers

Meeting Friends for

Bowling league

High School Football

DO NOT ANSWER PHONE!!!

Meeting Friends for

Bowling league

High School Football

DO NOT ANSWER PHONE!!!

Call from LabCall from Lab

We have 2 patients with multi-drug resistant Acinetobacter baumanni SputumBronchial Washing

We have 2 patients with multi-drug resistant Acinetobacter baumanni SputumBronchial Washing

Questions to ask yourselfQuestions to ask yourself

What do I know about Acinetobacter baumanni?

Is this normal sensitivity? Is this the 1st time we have seen

this?What can I do at 4pm on Friday?

What do I know about Acinetobacter baumanni?

Is this normal sensitivity? Is this the 1st time we have seen

this?What can I do at 4pm on Friday?

Acinetobacter baumannii

Acinetobacter baumannii

Characteristics:• Gram negative aerobic coccobacillus• Common in environment worldwide

– Water– Soil– Human normal flora

• Rarely known as disease causing agent

Characteristics:• Gram negative aerobic coccobacillus• Common in environment worldwide

– Water– Soil– Human normal flora

• Rarely known as disease causing agent

Acinetobacter baumannii

Acinetobacter baumannii

• Increasingly identified in nosocomial outbreaks

– Intensive care units– Immunocompromised patients– Ventilator support

“CDC data indicate A. baumannii was responsible for 1% of all nosocomial infections and 4% of nosocomial pneumonia in the United States.”

• Increasingly identified in nosocomial outbreaks

– Intensive care units– Immunocompromised patients– Ventilator support

“CDC data indicate A. baumannii was responsible for 1% of all nosocomial infections and 4% of nosocomial pneumonia in the United States.”

Acinetobacter: Transmission

Acinetobacter: Transmission

Patient-to-patient via transient carriage on hands of HCW

Devices, equipment, or environmental surfaces contaminated from a patient

Patient-to-patient via transient carriage on hands of HCW

Devices, equipment, or environmental surfaces contaminated from a patient

MDR-ABMDR-AB

Resistant to all antibiotics testedVery little risk to healthy peopleCan survive on environmental

surfaces several days

Resistant to all antibiotics testedVery little risk to healthy peopleCan survive on environmental

surfaces several days

Isolate??Isolate??

Meets definition in your policy?Meets definition in your policy?

The decision to investigate is influenced by…

The decision to investigate is influenced by…

morbidity / mortalityunusual presentation – rare

disease, change in pattern, new disease

gut feel…could it be the real thing ….does it look like a duck, quack like a duck….?

morbidity / mortalityunusual presentation – rare

disease, change in pattern, new disease

gut feel…could it be the real thing ….does it look like a duck, quack like a duck….?

Call received from ID Physician

Call received from ID Physician

He has a patient at the rehab hospitalWas in Baylor ICU for 3 weeks

recentlyCulture of sputum shows a totally

resistant Acinetobacter baumanni. “Just thought you would like to know.”

He is really an interesting patient Flown to Baylor from Middle East with

injuries from ejecting from his jet.

He has a patient at the rehab hospitalWas in Baylor ICU for 3 weeks

recentlyCulture of sputum shows a totally

resistant Acinetobacter baumanni. “Just thought you would like to know.”

He is really an interesting patient Flown to Baylor from Middle East with

injuries from ejecting from his jet.

There are now 3 patients reported

Need to act quicklyNot “quick and dirty” but “quick

and clean”No one “right” list, but everyone

needs a checklist to ensure systematic approach and to ensure that you don’t miss any key steps.

Need to act quicklyNot “quick and dirty” but “quick

and clean”No one “right” list, but everyone

needs a checklist to ensure systematic approach and to ensure that you don’t miss any key steps.

Important Checklist Considerations

Important Checklist Considerations

Report to local Health Department, if reportable

Have specimens heldDetermine how high to

communicateDetermine PR, Risk Management

involvementCommunicate, communicate,

communicateWrite final report

Report to local Health Department, if reportable

Have specimens heldDetermine how high to

communicateDetermine PR, Risk Management

involvementCommunicate, communicate,

communicateWrite final report

Case FindingCase Finding

Be systematic and comprehensive in case finding. Case finding is determine the extent of the outbreak (who is affected? are there more cases than those that might have been the first to be reported? what is the geographic extent?)

Line list is like a spreadsheet with each row representing a case; each column is a key variable such as name or initials, date of onset of illness, diagnosis lab confirmed?, age, sex, etc.

Be systematic and comprehensive in case finding. Case finding is determine the extent of the outbreak (who is affected? are there more cases than those that might have been the first to be reported? what is the geographic extent?)

Line list is like a spreadsheet with each row representing a case; each column is a key variable such as name or initials, date of onset of illness, diagnosis lab confirmed?, age, sex, etc.

AAA

CINDEX CASE

4 N – ICU

• Trauma Unit

• Averages 630-670 patient days

• 4 – 4 bed pods, 2 – 3 bed pods

• Construction overhead

• Requires movement of patients away from noise.

Confirm existenceConfirm existence

Is this a cluster or outbreak?Real versus artifact – not all

apparent increases in disease reflect true increases. Some are due to artifacts of reporting – change in diagnostic test or case definition, improved reporting, heightened awareness, etc.

Is this a cluster or outbreak?Real versus artifact – not all

apparent increases in disease reflect true increases. Some are due to artifacts of reporting – change in diagnostic test or case definition, improved reporting, heightened awareness, etc.

2 more patients reported2 more patients reported

AA ACCBF D

Meeting CalledMeeting Called

Chief Nursing Officer ID physician ICU DirectorNursing ManagerDirector, Respiratory TherapyMicrobiology Lab

Chief Nursing Officer ID physician ICU DirectorNursing ManagerDirector, Respiratory TherapyMicrobiology Lab

Agenda for MeetingAgenda for Meeting

What has been reportedBrief education What has been identified so far -

Line ListingControl Measures that must be re-

enforcedHold all specimens for PFGE testingAny ideas of transmission modeDetermine next steps

What has been reportedBrief education What has been identified so far -

Line ListingControl Measures that must be re-

enforcedHold all specimens for PFGE testingAny ideas of transmission modeDetermine next steps

Continue InvestigationContinue Investigation

Index CaseIndex Case

F-16 fighter pilot Instructor for United Arab Emirates

F-16 fighter pilot Instructor for United Arab Emirates

United Arab EmiratesUnited Arab Emirates

Comprised of 7 emirates (states)Abu Dhabi is largestBorders Saudi Arabia and OmanNorth - Iranian military airportTake national defense seriouslyUAE Air Force 65,000 troopsVery well equipped Air Force2005 addition of 80 F-16’s

Comprised of 7 emirates (states)Abu Dhabi is largestBorders Saudi Arabia and OmanNorth - Iranian military airportTake national defense seriouslyUAE Air Force 65,000 troopsVery well equipped Air Force2005 addition of 80 F-16’s

Index Case Index Case

Apparently entered a loop too low or had a density altitude problem

F-16 hit the ground in full burner Pilot ejected Chute didn't have time to fully deploy Injuries included:

Flail chest Broken leg Back fractures Liver laceration etc.

Apparently entered a loop too low or had a density altitude problem

F-16 hit the ground in full burner Pilot ejected Chute didn't have time to fully deploy Injuries included:

Flail chest Broken leg Back fractures Liver laceration etc.

do

Index CaseIndex Case

2-3 Days in Abu Dhabi hospitalAir lifted to London hospital

Wound infected and debridedStop over in Iceland due to change

in conditionArrived at BUMC 1/24/06Discharged to Rehab facility on

2/14/06

2-3 Days in Abu Dhabi hospitalAir lifted to London hospital

Wound infected and debridedStop over in Iceland due to change

in conditionArrived at BUMC 1/24/06Discharged to Rehab facility on

2/14/06

Case DefinitionCase Definition

Standard case definition is essential so that all cases are classified the same way regardless of where they occur and who the investigators are.

Criteria – not only clinical features, but for outbreak need to specify time (have far back do you go to say that a case was part of this outbreak?),

Loose (sensitive) versus tight (specific) case definition – often looser early to capture as many possible cases as possible, then may narrow.

Standard case definition is essential so that all cases are classified the same way regardless of where they occur and who the investigators are.

Criteria – not only clinical features, but for outbreak need to specify time (have far back do you go to say that a case was part of this outbreak?),

Loose (sensitive) versus tight (specific) case definition – often looser early to capture as many possible cases as possible, then may narrow.

Descriptive EpidemiologyDescriptive Epidemiology

Time – begin with describing when people became ill/culture date. Usually displayed graphically with epidemic curve (“epi curve” for short) – histogram (not bar chart) with time on X axis, # cases on Y axis

Place – where were the patients located? Person – who are they? All ages, both

sexes, or restricted to just some groups?

Time – begin with describing when people became ill/culture date. Usually displayed graphically with epidemic curve (“epi curve” for short) – histogram (not bar chart) with time on X axis, # cases on Y axis

Place – where were the patients located? Person – who are they? All ages, both

sexes, or restricted to just some groups?

Prior to Intervention

0

1

2

3

4

5

1/24

/200

6

1/31

/200

6

2/7/

2006

2/14

/200

6

2/21

/200

6

2/28

/200

6

3/7/

2006

3/14

/200

6

3/21

/200

6

Nu

mb

er o

f C

ases

AA ACCBF D

4T

F G H I K

AA ACCBF

D

D

4W

E J L

MDR-ABCulture Source

0

2

4

6

8

10

12

14

16

18

Nu

mb

er

Routine Surv.

Surv. 5 2

Routine 11 8 5 4

Sputum Wound Urine Blood

MDR-AB Cultures by Date

0

1

2

3

4

5

1/24

/200

6

1/31

/200

6

2/7/

2006

2/14

/200

6

2/21

/200

6

2/28

/200

6

3/7/

2006

3/14

/200

6

3/21

/200

6

3/28

/200

6

4/4/

2006

4/11

/200

6

4/18

/200

6

4/25

/200

6

5/2/

2006

5/9/

2006

5/16

/200

6

Nu

mb

er

Intervention

Implement Control Measures

Implement Control Measures

Eliminate the source Interrupt mode of transmissionReduce susceptibility

Eliminate the source Interrupt mode of transmissionReduce susceptibility

Control MeasuresControl Measures

Maximum Isolation PrecautionsGowns and gloves on entry

Hand Hygiene..Hand Hygiene..HHCohort Patients with MDR-AB

Use reverse isolation for non MDR-ABTerminal Cleaning of RoomsEvaluation of common processesSurveillance cultures of patients

Maximum Isolation PrecautionsGowns and gloves on entry

Hand Hygiene..Hand Hygiene..HHCohort Patients with MDR-AB

Use reverse isolation for non MDR-ABTerminal Cleaning of RoomsEvaluation of common processesSurveillance cultures of patients

1

2

208

763

14

13

421

11

23

24

18

10 12

15 16

5

2219

17OR

ET

2526

27

Transmission Matrix – Spot Map

Baylor University Medical Center Dallas

Rep-PCR Typing Results 28-Apr-06

Culture by Date

0

1

2

3

4

5

Cultu

re P

ositi

ve

Intervention New Strain

One Year LaterOne Year Later

ConclusionConclusion

Investigation usually need to be done quickly, and always needs to be done well

Know your roleUse systematic approachKeep each step simple and

manageableCommunicate findings

Investigation usually need to be done quickly, and always needs to be done well

Know your roleUse systematic approachKeep each step simple and

manageableCommunicate findings

Acinetobacter OutbreaksAcinetobacter Outbreaks

Judy Prescott RN, BSN, CICJudy Prescott RN, BSN, CICBaylor University Medical Center

Dallas, Texas214-820-3456

judypr@baylorhealth.edu

Baylor University Medical CenterDallas, Texas214-820-3456

judypr@baylorhealth.edu