Outbreak Investigation Phicna Lect 2014

•Outbreak: Tell-Tale Signs, Investigations, Actions & Solutions

• SILVEROSE ANN A. ANDALES-BACOLCOL, M.D., FPCP, FPSMID

• Internal Medicine and Infectious Diseases

• OUTLINE of this LECTURE:

• I. Definition of terms• II. How outbreaks are recognized• III. Reasons for investigating outbreaks• IV. Constraints of outbreak investigation• V. Infection Control Measures• VI. Preparing for the Investigation• VII. Steps in conducting an outbreak investigation

in health care facilities• VIII. Case Study

• I. Definition of terms

• A. What is an outbreak? An incident in which two or more people who are

thought to have a common exposure experience a similar illness or proven infection.

The occurrence of more cases of a disease than expected: in a givenplace among a specific group of people orpopulation in a particular period oftime


• B. Epidemic- same as outbreak but more widespread or prolonged

l C. Healthcare-associated infections- are infections that occur in patients or healthcare

workers as a result of healthcare interventionsl D. Hospital-acquired infections

- Infections acquired during hospital stay which were not incubating at the time of admission


• E. Health Care Facilities- Hospital- Private physician’s office- Outpatient clinic

- Dialysis centers- Ambulatory surgery- Endoscopy units

- Long term care facilities- Nursing homes- Rehabilitation centers- Institutions for mentally or physically

handicapped

• II. How are outbreaks recognized?

A. By the clinician, infection control professional, nurse, or medical staff

B. By the laboratory personnel or microbiologist

C. By the patient or patient’s familyD. Hospital or healthcare-associated

infection routine surveillance dataE. Unusual agent, site or host

• When to Consider Nosocomial Transmissionof Infectious Diseases?

A cluster of similar infections occurs on one hospital unit or among similar patients

A cluster of infections associated with invasive devices occurs

HCWs and patients develop the same type of infection A cluster of infections with organisms typically

associated with hospital-acquired infections (MDR or opportunistic organisms)

• Determine Risk Factors for Disease or Nosocomial Infection

Host risk factors for HAI Invasive devices Severity of illness Underlying diseases (Malignancy, HIV) New technology (Chemo agents)

Environmental risk factors Location (ICU vs. Ward)

• III. Reasons for investigating outbreaks

A. Prevent additional cases in the current outbreakB. Prevent future outbreaksC. Assess prevention interventionsD. Learn about a new diseaseE. Learn something new about an old disease

• New sources• Unusual modes of transmission• Complications of new procedures

F. Reassure the publicG. Minimize economic and social disruption

• Negative Effects of Outbreaks

• Outbreaks cause Morbidity, mortality Prolongation of stay Additional procedures Increases cost Bad reputation

• IV. Constraints of Outbreak Investigation

A. Urgency to find source and prevent cases

B. Pressure for rapid conclusionsC. Pressures because of legal and

financial liabilityD. Delays can limit human/ environmental

samples for testing

• V. Infection Control Measures

Introduce preventive interventions before initiating or completing an investigation. Handwashing in-service sessions Close a unit to new admissions Remove a product or device

Carefully weigh the potential benefit of more drastic measures against the potential harm to patients currently residing in the facility

• VI. Preparing for the Investigation

All levels of the health care facility’s personnel must be committed. Hospital Administration Infection Control Unit Chief of the affected service Head Nurse or Supervisor Head of Microbiology Health care professionals (Doctors, nurses)


Consider availability of microbiologic isolates for antimicrobial sensitivity (or molecular typing)

Inform Microbiology Lab early Save specimens and isolates Be alert for additional isolates that may be

part of the outbreak


Identify the following: Resources (personnel, supplies, laboratory) Lead investigator Person responsible for statistical analysis of

the data

• VII. STEPS IN CONDUCTING AN OUTBREAK INVESTIGATION

• Step 1: Learn about the topic• Step 2: Establish the Existence of an Outbreak• Step 3: Verify the Diagnosis• Step 4: Define and Identify Cases• Step 5: Describe and orient the data in terms of

time, place, and person• Step 6: Develop Hypotheses• Step 7: Evaluate Hypotheses• Step 8: Refine Hypotheses and Draw Conclusions• Step 9: Implement Control and Prevention

Measures• Step 10: Communicate Findings

•Step 1: Learn about the topic

• Research about the disease through Infectious Diseases practitioner Clinical Epidemiologist Laboratory personnel Infection control/ Infectious

Diseases textbooks Medical Journals

• Step 2: Establish the Existence of an Outbreak

• IS THIS AN OUTBREAK?• More cases than expected in a given place

over a given time.• Determine the expected number of cases

for the area in the given time frame.• Compare the current number of cases with

the number from the previous weeks, months or years

Hospital surveillance records Hospital discharge records or census Morbidity and mortality records


• IS THIS A PSEUDO-OUTBREAK?• Clusters of positive cultures in patients

without evidence of disease (colonization)• A perceived increase in infections because

surveillance was not previously being conducted or because surveillance definitions, intensity or methods have changed


• What could cause an artificial increase (pseudo-outbreaks)? Alterations in surveillance system:

New personnel New definition New case finding method New procedure in reporting

Increased awareness New Laboratory procedure

New diagnostic tests, laboratory equipment New technician

New susceptible population New ward, increase in size of population

• Step 3: Verify the Diagnosis

• Ensure that the disease has been properly diagnosed.

• Be certain that the increase in diagnosed cases is not the result of a mistake in the laboratory.

• Confirm the diagnosis: Clinical syndrome (signs & symptoms) Epidemiologic risk (person, place, time) Laboratory & diagnostic tests

• Step 4: Define and Identify Cases

• Establish a case definition– Inclusion criteria:– A. Clinical criteria (symptoms, signs & onset)– B. Epidemiologic criteria (person, place, time)– C. Laboratory criteria (culture results & dates)– Case Classification:– A. Suspect/Possible- fewer of the typical clinical features– B. Probable- has the typical clinical features of the disease

without laboratory confirmation– C. Confirmed- has the typical clinical features of the

disease and laboratory confirmation– Exclusion Criteria(for suspect and probable)


• Identify and count cases Interview staff, patients Review patients records, log books, employee health

records Review lab records Infection surveillance data

Passive surveillance Send out letters describing the situation and ask for

reports Active surveillance

Do telephone surveys or visit the facilities to collect information


• Collect Case Data Identifying information Demographic information Clinical information Risk factor information

Underlying diseases Invasive procedures Surgical risk factors

Laboratory test results

• Step 4: Define and Identify Cases• Complete Line Listing

A table consisting of important variables such as identification number, age, sex, signs& symptoms, lab test results.

New cases are added to a line listing as they are identified.

• Case #

• Initials

• Date of report

• Date of onset

• Diagnosis

• Age

• Sex

• symptoms

• P.E.

• Labs

• 1 • MC • 2/13 • 2/4 • HAP • 67 • M • Cough, fever

• crackles

• CXR,

• Step 5: Describe and Orient the Data in Terms of Time, Place, and Person

• Descriptive Epidemiology

Provide a comprehensive description of an outbreak by showing its trend over time, its geographic extent (place), and the populations (people) affected by the disease.

• Time: Epidemic Curve

• Epidemic curve A graph of the number of cases by their date

of onset Gives a simple visual display of the outbreak’s

magnitude and time trend. Y axis= # of cases X axis= date of onset/time

•Epidemic Curve

• Epidemic Curve

• Place: “Spot Map”

• Ground floor • 2nd floor

• Blue Unit (vacant)

• Green Unit

• Red Unit

• Brown Unit

• Social

• Admin

• Kitchen

• Laundry

• Clinics

• Services

• Business

• Office

• Classes

• Technical

• 3

• 24

• 8

• 6• 2

• 7

• 4• 5• 1

4

• 9

• 1• 13

• 12• 1

1• 1

0

• 18• 1

7

• 16

• 15• 2

3• 2

2

• 21

• 20• 1

9

• 29

• 28

• 27

• 26

• 25

• 33 • 3

2

• 31

• 34

• 31

• 30

• 33

• 35

• 36

• 37

• 1• 2

• 3

• 4

• 8

• 7 • 6• 5

• 12

• 11

• 10

• 9

• 17

• 16

• 15

• 14• 1

3

• 24

• 19

• 18

• 23

• 22

• 21

• 20

• 27

• 26

• 25

• 28

• 29

• 30

• 31

• 32

• 33

• 35

• 36

• 37

• 38

• 39

• 40

• 41

• 42

• Person

• Determine what populations are at risk for the disease by characterizing by person. Age, gender Health status:

Increased susceptibility Risk factors Underlying disease

Exposures Procedures Drug, IV line

• Step 6: Develop Hypotheses

Formulate a hypothesis to explain why and how the outbreak occurred based on results of preliminary investigation.

Hypothesis should address the source of the agent, the mode of transmission, and the exposures that caused the disease. Clues from clinical syndrome Clues from etiologic agent Clues from case interviews (have in common?) Clues from existing knowledge base

• Step 7: Evaluate Hypotheses

Comparison of the hypotheses with the established facts.

Analytic Epidemiology Cohort studies

Compare groups of people who have been exposed to suspected risk factors with groups who have not been exposed.

Case-control studies Compare people with disease (case patients) with a

group of people without the disease (controls) Statistical Methods Lab and Environmental Studies

• Step 8: Refine Hypotheses and Draw Conclusions

When an outbreak occurs, you should consider what questions remain unanswered about the disease.

Draw conclusions from descriptive or analytic studies

Causal inferences

• Step 9: Implement and EvaluateControl and Prevention Measures

Should be implemented early Control strategies:

Reduce contact between susceptibles and potential infectives

Reduce probability source is infective Reduce infectiousness of infectious source

By treatment Reduce susceptibility of susceptible hosts

By treatment/prophylaxis or vaccination Interrupt transmission

Physical/Chemical methods Environmental/Engineering methods

• Prevention at Source of Infection

Human source: Isolation or treatment of the

human source

Length of time the patient is infectious after treatment must be known

• Prevention of Transmission

Contact and indirect contact: Prevent contact, wear gloves if contact

isnecessary, handwashing Airborne or Droplet:

Wearing mask with sufficient filtering ability.

Simple surgical mask sufficient for large droplet (as long as the mask is dry)

Masks with HEPA type filters for droplet nuclei

Food and water borne: Avoid suspected food and water

• Prevention: Protection of At Risk Person

Protection of susceptible

individuals

Immunization (passive or

active, if time permits)

Chemoprophylaxis

• Step 10: Communicate Findings

• 1. Communicate preliminary assessments and recommendations (letter, memo) Communicate any changes necessitated by the

outbreak analysis to the appropriate departments

2. Prepare interim/final report Issue a concluding report to the hospital or

healthcare facility committees

• VIII. CASE STUDY

An ICC nurse receives a report from the NICU of an increased number of cases of sepsis 2 toBurkholderia cepaciabloodstream infection among newborns who were delivered via normal spontaneous delivery from January1-31, 2013.

For the month of January 2013, 16 out of 59 newborn babies were treated for sepsis. For the 16 patients, blood cultures were taken during the first few hours of life (ranging from 6 hours to 24 hours). All blood cultures were positive forBurkholderia cepacia.

• OUTBREAK INVESTIGATION:CASE STUDY

• Step 1: Learn about the topic

• The ICC nurse looks upBurkholderia cepaciain her desk copy of Bergy’s Manual of Systematic Bacteriology and Infectious Diseases textbook by Mandell. She found out thatBurkholderia cepaciais a gram negative bacillus commonly found in soil and moist environments and capable of surviving and growing in nutrient-poor water. It is an important opportunistic pathogen in hospitalized and immunocompromised patients.


• Step 2: Establish the existence of an outbreak

• The NICU averages about 2 % infections per month. The rate of infection appeared to begin to rise around August.

• December’s BSI rate was 3% and January’s rate was 27%.

• There was no past record of BSI caused byBurkholderia cepacia.However, there were past records of BSI caused by other organisms(Pseudomonas aeruginosa and Staphylococcus aureus)


• Step 3: Verify the diagnosis

• The ICC nurse reviewed the charts and culture results of the 16 patients who developed BSI.

• She visited 5 of the patients with a positive culture forB. cepaciawho were still admitted.

• She asked the medical and nursing staff from NICU and DR if there were any new personnel, new practices, equipment or solutions used.



• The initial case definition is,“Any newborn baby developing a BSI following normal spontaneous delivery performed in the past 6 months. ”

• The ICC nurse called the micro lab and asked for 2 reports:

• one screening for Blood cultures from the NICU and another screening for any positiveBurkholderia cepaciacultures from the NICU from August 2012 to present.


• Step 5: Describe and Orient the Data in terms of time, place, and person

• All charts were reviewed using a data collection form developed by the ICC. Seven additional BSI’s were identified related to January 2013 deliveries.Burkholderia cepaciacaused five of the infections.

• Place

A total of 59 babies were delivered in the month of January. 35 babies were delivered via NSD while 24 were via CS. All 16 babies with BSI were delivered via NSD in Delivery Room # 3.

NSDs are performed in DR # 3 and 4. Cesarean Deliveries are performed in DR # 1 and 2

• Person

Obstetrician Xis associated with 9/16 deliveries of newborns who developedBurkholderia cepaciaBSI. She has been practicing for 10 years in the hospital.

Nurse A, a DR nurse assisted the deliveries of 16/16 knownBurkholderia cepaciaBSI cases. Records showed that she was newly hired and started on January 1, 2013

Nurse B, a NICU nurse performed newborn care to 8/16 babies who developedB. cepaciaBSI. She has been employed for 5 years.


• Step 6: Develop a Hypothesis

• It was decided to narrow down the case definition to:

• A BSI that is culture positive forBurkholderia cepaciain a newborn patient who was delivered via NSD in the month of January 2013.

• The tentative hypothesis is that patients are being exposed toBurkholderia cepaciain the Delivery Room or NICU.


• Step 7: Test the Hypothesis

• The ICC nurse notes that Obstetrician X was involved in 9/16 cases,

• Nurse B was involved in 8/16 cases, and Nurse A was involved in all 16/16 cases.

• She decides to determine if their presence during these deliveries is significant.


• Step 7: Test Hypotheses

The ICC nurse reviewed perinatal and intra-operative care by interviewing obstetricians, OB and Pedia residents, and other D.R. and NICU personnel and by observing a NSD procedure performed by Obstetrician X in D.R. # 3 where both Nurse A & Nurse B were assisting.

Nurse A prepared the patient in labor prior to NSD. Aseptic technique was performed. Cotton cherries pre-soaked in betadine solution was used for cleaning the perineal area. The umbilical cord was clamped using sterile clamps and was cut by a disposable sterile blade.



Nurse B assisted the Pediatrician in performing newborn care. Aseptic technique was performed while handling the baby. Sterile suction tubing was used for suctioning of airways. The newborn was bathed using pre-boiled water. Cord care was done using 70% isopropyl alcohol.



Environmental cultures were done to determine the source of the outbreak.

A culture of the ff. were done: Cotton cherries pre-soaked in Betadine solution

in DR #3 Betadine solution stored in big bottles at DR #3 Kelly pads in DR# 3 Pre-boiled water used for bathing newborns Bath tub used during bathing of newborns



• Result of cultures:

Cultures of cotton cherries pre-soaked in Betadine solution in DR #3 grewBurkholderia cepacia.



Newborn babies who were delivered via NSD in January 2013 developed Bloodstream infection due to exposure toBurkholderia cepaciain Delivery Room # 3.

The technique used by Nurse A in preparing patients in labor by using cotton cherries pre-soaked in contaminated Betadine solution for cleaning the perineal area caused the exposure of newborn babies toB. cepaciaduring delivery.


• Step 9: Implementing Control and Prevention Measures

The ICC nurse recommends a change in procedure in preparing patients in labor prior to NSD.

Cherries pre-soaked in betadine solution used for prep were not allowed in the DR. Sterile cotton cherries packed for single use and Betadine solution stored in small sterile containers were recommended.

Aseptic technique during delivery and newborn care was reinforced.

Nurse A was required to attend in-sevice ICC seminar.


• Step 10: Communicate Findings

All staff was informed of findings and the procedure change.

A written summary of findings was distributed to appropriate staff.

• STEPS IN CONDUCTING AN OUTBREAK INVESTIGATION

• Step 1: Learn about the topic• Step 2: Establish the Existence of an Outbreak• Step 3: Verify the Diagnosis• Step 4: Define and Identify Cases• Step 5: Describe and orient the data in terms of

time, place, and person• Step 6: Develop Hypotheses• Step 7: Evaluate Hypotheses• Step 8: Refine Hypotheses and Draw Conclusions• Step 9: Implement Control and Prevention

Measures• Step 10: Communicate Findings

• OUTBREAK INVESTIGATION WORKSHOP

• MECHANICS:

1. THE LINK NURSES SHALL BE DIVIDED INTO 4 SMALL GROUPS.

2. EACH GROUP SHALL BE GIVEN A CASE SCENARIO.

3. THE MEMBERS OF THE GROUP SHALL ANALYZE THE SCENARIO USING THE 10 STEPS OF OUTBREAK INVESTIGATION.

4. ONE REPRESENTATIVE FROM THE GROUP WILL PRESENT THEIR ANALYSIS AND RECOMMENDATIONS AT THE END OF THE GROUP SESSIONS.

• VIII. CASE STUDY

On March 2014, the ICU Link Nurse was the charge nurse on duty. Upon updating the cultures of patients, the link nurse has noticed that 4 out of 10 patients in the ICU have growth of Klebsiella Pneumoniae Carbapenemase (+) in their cultures.

The Link Nurse immediately notified the Infection Prevention and Control Office. The surveillance coordinator together with the Link Nurse conducted an on-the-spot audit of Infection Prevention and Control Practices of all healthcare workers at the ICU and reviewed the interactions that occurred with the patients.


– Step 1: Learn about the topic

• The link nurse reads aboutKlebsiella pneumoniae carbapenemasefrom

• the Infectious Diseases textbook by Mandell. She found out thatKlebsiella pneumoniae carbapenemaseis a gram negative bacteria which develop resistance to most antibiotics including cabapenems. It is a common cause of nosocomial infections such as UTI, pneumonia, and meningitis. It is an important opportunistic pathogen in hospitalized and immunocompromised patients.


• Step 2: Establish the existence of an outbreak

• The rate of infection due to KPC at the ICU appeared to begin to rise around March 2014.

• The KPC HAI rates for the past 6 months were reviewed.

• There were no HAIs 2 to KPC last October, November, January and February 2014.

• There was a past record of HAI 2 to KPC last December (2 cases of UTI).


– Step 3: Verify the diagnosis

• The ICU link nurse reviewed the charts and culture results of the 4 patients who developed HAI 2 to KPC.

• She correlated the culture results with the clinical findings of the patients.– Patient A.N.- VAP 2 to KPC– Patient B.L- VAP 2 to KPC– Patient N.D.- CAUTI 2 to KPC– Patient S.R.- Infected Decubitus

ulcer 2 to KPC

• OUTBREAK INVESTIGATION:CASE STUDY• Step 4: Define

and Identify Cases

• The initial case definition is,“Any ICU patient developing a HAI secondary to KPC in the month of March 2014. ”

• The ICU link nurse called the micro lab and asked for a report:

• A report screening for any positive culture ofKlebsiella pneumoniae carbapenemasefrom the ICU from March 1 to 31, 2014.

• OUTBREAK INVESTIGATION:CASE STUDY• Step 4: Define

and Identify Cases

• Line List:

• Name

• Isolate • Source

• Room #

• Date collected

• Date admitted at ICU

• Date transferred to floor

• A.N. • (+) KPC

• ETA • ICU 2 • 3/12/14 • 3/10/14 • 3/15/14

• B.L. • (+) KPC

• ETA • ICU 2 • 3/8/14 • 3/4/14 • 3/10/14

• N.D. • (+) KPC

• Urine • ICU 5 • 3/5/14 • 3/2/14 • 3/15/14

• S.R. • (+) KPC

• Wound

• ICU 9 • 3/8/14 • 3/5/14 • 3/11/14


• Step 5: Describe and Orient the Data in terms of time, place, and person

• All ICU charts were reviewed using a data collection form developed by the IPCO.

• Place

ICU 2 = 2 CASES (Patients B.L. & A.N.) ICU 5 = 1 CASE (Patient N.D.) ICU 9 = 1 CASE (Patient S.R.)

• Person

• RISK FACTORS FOR KPC HAI:

Patient A.N. was intubated since 3/08/2014. He is under the care of Dr. B. He was cared by NurseLoveon 3/8/2014.

Patient B.L. was intubated since 3/4/2014. He is under the care of Dr. A. He was cared by NurseCompetenceon 3/8/2014.

Patient N.D. has a foley catheter since 3/4/2014. He is under the care of Dr. A. He was cared by NurseCompassionon 3/5/2014.

Patient S.R. has a 2 x 2 bedsore observed since 3/5/2014. He is under the care of Dr. C. He was cared by NurseCompetenceon 3/8/2014. He was also handled by NurseCompassionon 3/5/2014.


• Step 6: Develop a Hypothesis

• The tentative hypothesis is thatKlebsiella pneumoniae carbapenemaseinfection is being transmitted from an index case to other patients in the ICU probably because of a break in infection control practices.


• Step 7: Test the Hypothesis

• The ICU link nurse notes that Nurse Compassion was involved in 2/4 cases and in the first case of KPC (patient N.D.)

• Nurse Competence was involved in 2/4 cases, and Nurse Love was involved in 1/4 cases.

• Dr. A was involved in 2/4 cases (B.L. and N.D.)

• She decides to determine if their presence are significant by conducting an audit of their practices.



• Audit of Healthcare Worker Practices:

• Nurse Competence has a hand hygiene compliance of 15%.

• • Nurse Compassion has a hand hygiene

compliance of 50%, but he uses the same gloves for draining the urinary bag.

• • Dr. B and A both have a hand hygiene

compliance of 30%.• • On 3/10/2014, Patient A.N. was immediately

admitted to the ICU-2 post-OR due to severe hemodynamic instability. The room has just been vacated by Patient B.L.



Environmental cultures at the ICU were done to determine the source of the outbreak.

A culture of the ff. were done: Bedrails at ICU Beds 2,5,9

Gloves used by Nurse Compassion for draining urine of patient N.D.



• Result of cultures:

Bedrails at ICU Beds 2 & 5 were positive for KPC

Gloves used by Nurse Compassion for draining urine of patient N.D. was positive for KPC



Patient N.D. with CAUTI 2 to KPC is the index case (infected March 5, 2014).

Nurse Compassion transmitted KPC from the urine of Patient N.D. to the wound of Patient S.R. on March 5, 2014 because she does not change gloves when draining the urine bag.

Patient B.L developed VAP 2 to KPC on March 8, 2014 which was transmitted from Patient S.R. through the contaminated hands of Nurse Competence (HHC of 15%).



The wound of Patient S.R. was infected with KPC on March 8, 2014 which was transmitted from patient B.L. through the contaminated hands of Nurse Competence (15% Hand hygiene compliance).

Patient A.N. developed VAP 2 to KPC on March 12, 2014 because of inadequate environmental cleaning of ICU 2 which was just vacated by Patient B.L. with VAP 2 to KPC.


• Step 9: Implementing Control and Prevention Measures

• The ICU link nurse recommends the following:

Implement contact precautions for all patients with KPC HAI and Droplet Precautions for all patients with VAP 2 to KPC.

Gloves used for draining urine should be disposed immediately after single use.

Routine environmental cleaning of all ICU cubicles should be done.

Nurse Competence and Nurse Compassion were required to attend in-sevice Infection Control seminar.

• OUTBREAK INVESTIGATION:CASE STUDY• Step 10:

Communicate Findings

All staff was informed of findings and the recommendations.

A written summary of findings was distributed to appropriate staff.

l Thank you for your attention!

• References:

http://www.cdc.nationalcenter for chronic disease prevention and health promotion.Outbreak Investigation

http://www.idready.org. Aragon, T., W. Enanoria, A Reingold.Conducting an outbreak investigation in 7 steps. Center for Infectious Disease Preparedness, UC Berkeley School of Public Health.

Outbreak investigation-Case Study by University of Michigan Hospitals and Health Centers, Infection Control & Epidemiology 2002.

Outbreak Investigation Phicna Lect 2014

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