Outbreak Investigation of Healthcare Associated Infections

Outbreak Investigation

of Healthcare-associated Infections

Ma. Liza Antoinette M. Gonzales, MD, MSc, FPPS,

Associate Professor, Department of Pediatrics

University of the Philippines Manila

Objectives of this session

• Define what is meant by an outbreak

• Discuss the steps of an outbreak

investigation in the hospital

• Apply the steps in a hypothetical

case of an outbreak

Healthcare-associated

Infections (HAI)

• Also referred to as “nosocomial” or “hospital-

acquired” infection, is defined as:

• An infection occurring in a patient during the

process of care in a health-care facility which

was not present or incubating at the time of

admission.

• Usually occur at 48 hours or more after

admission

• Includes infections acquired in the hospital but

appearing after discharge and occupational

infections among staff.

Garza D & Becan-McBride. Phlebotomy Handbook: Blood Collection Essentials, Seventh Edition 2005

Pearson Education.Copyright 2005

Nosocomial Infections

Risk Factors for HAI

• Prolonged use of invasive devices

• Inappropriate use of antibiotics

• High-risk and sophisticated procedures

• Immuno-suppression

• Severe underlying patient conditions

• Admission to the ICU

• Insufficient application of standard and

isolation precautions

• Inadequate infection control and

prevention measures

WHO, Infection Control. http://www.who.int/csr/bioriskreduction/infection_control/en/index.html

Risk Factors in settings with

limited resources:

• Inadequate

environmental hygienic

conditions and waste

disposal

• Poor infrastructure

• Insufficient equipment

• Understaffing

• Overcrowding

• Lack of procedure

• Poor knowledge and

application of basic

infection control

measures

• Lack of knowledge of

injection and blood

transfusion safety

• Absence of local and

national guidelines and

policies


Common Healthcare-associated

infections

• Blood-stream infection

• Central line-associated bloodstream

infections

• Hospital acquired / Ventilator-

associated pneumonia

• Catheter-associated urinary tract

infections

• Surgical site infections

What is an Outbreak?

• An Outbreak is defined as an increase in

occurrence of cases (HAI) above what is

expected in that population in that area

over a particular period of time

• Important to consider or establish

background rate

• One case of a rare occurrence or many

episodes of a common occurrence can be

an outbreak

CDC. Principles of Epidemiology in Public Health Practice . 3rd ed. Updated 2012

Epidemics and Clusters

• Epidemic - same as outbreak but used for

a wider geographic area

• Cluster - aggregation of cases in a given

area over a particular period without

regard to whether the number of cases is

more than expected; some are true

outbreaks, some are sporadic and

unrelated cases of the same or unrelated

disease

CDC. Principles of Epidemiology in Public Health Practice . 3rd ed. Updated 2012

Exercise 1

• Which of the following situations can be

an outbreak?

A. Two adult patients with COPD develop

pneumonia after admission to the general

medical wards

B. One patient in the surgical ward develops

purulent discharge on the surgical incision

site

C. 10 postpartum women develop abdominal

wound dehiscence after cesarean section

within 2 weeks

D. Two cases of varicella in the pediatric ICU

within 5 days

✔

✔

Reasons for Investigating

Outbreaks

• Identify the source and control

further transmission

• Develop strategies to prevent future

outbreaks

• Evaluate existing prevention

strategies

• Describe new diseases and learn

more about known diseases

• Address public concernReingold AL. Emerging Infectious Diseases 1998; 4 (1): 21-7.

Investigating an Outbreak


Systematic planning and

implementation of an outbreak

investigation is necessary

Outbreak Investigations:

The 10-Step Approach1. Identify investigation team and resources

2. Establish existence of an outbreak

3. Verify the diagnosis

4. Construct case definition

5. Find cases systematically and develop line listing

6. Perform descriptive epidemiology/develop

hypotheses

7. Evaluate hypotheses/perform additional studies as

necessary

8. Implement control measures

9. Communicate findings

10. Maintain surveillance

1. Identify the Investigation team

and resources

• Once an outbreak is suspected, notify

appropriate individuals and departments in the

institution (Chief of the affected service, head

nurse of the unit, hospital administration)

• Establish an Outbreak Investigation Team with

clear delineation of responsibilities

• Cooperation of various healthcare professionals

is essential for efficient investigation and

implementation of control measures

• Identify available resources: personnel,

supplies, laboratory

Who should be part of the

Outbreak Investigation Team?

• Infection control staff must be part

of the outbreak team.

• Other members:

– Local – Hospital Epi teams,

microbiologist, other trained medical or

clinical personnel

– National - Disease Investigation

Specialists; DOH-Epidemiology Bureau

– Others – WHO, Philippine FDA

2. Confirmation of Outbreak

• Confirm whether there is an

outbreak by reviewing the following:

– preliminary information on the number

of potential cases

– available microbiology

– severity of the problem

– demographic data of cases

– place and time

• Review definition of OUTBREAK

3. Verify the Diagnosis

• Review existing data

– Medical records/charts

– Surveillance records

– Microbiology

– Other Laboratory reports and records

• Interview unit medical/clinical personnel

and paramedical staff

• Clinical observations

• Contact Hospital Epidemiologist &

Infection Control team

• Conduct clinical testing if needed

4. Construct Case Definition

• Case definition is a set of standard criteria for

classifying whether a person has a particular

disease, syndrome, or other health condition.

• Decide what constitutes a case, what you are

looking for

• Narrow enough to focus efforts but broad

enough to catch all the cases

• Define 3 essential characteristics of disease:

Person, Place, Time

• A gradient of definition based on level of

evidence (as suspected, probable, or

definite/confirmed case) is often helpful

Case Definition

• Use previously published, validated

definitions if available and applicable

– e.g. CDC/NHSN Surveillance Definitions for

Specific Types of Infections 2017

• Where not available, use standardized

written case definitions to ensure precise

surveillance.

• Use the same definitions for accurate and

valid comparisons of data over time and

across institutions

CDC/NHSN 2017 Surveillance Definitions

for Specific Types of Infections

• Primary bloodstream infections (BSI): Laboratory-

confirmed bloodstream infections (LCBI) that are not

secondary to an infection at another body site

• Central line-associated BSI (CLABSI): A

laboratory-confirmed bloodstream infection (LCBI)

where central line (CL) or umbilical catheter (UC)

was in place for >2 calendar days on the date of

event, with day of device placement being Day 1,

AND the line was also in place on the date of event

or the day before.

CDC/NHSN 2017 Surveillance Definitions for

Specific Types of Infections

• Pneumonia (PNEU) - identified by using a

combination of imaging (new or progressing

abnormalities on chest imaging test), clinical(e.g.

New onset or worsening purulent sputum or cough,

or dyspnea or tachypnea and laboratory criteria

(culture of blood/respiratory specimens or

histopathologic test).

• Ventilator-associated pneumonia (VAP): A

pneumonia where the patient is on mechanical

ventilation for >2 calendar days on the date of event,

with day of ventilator placement being Day 1, AND

the ventilator was in place on the date of event or

the day before.

CDC/NHSN 2017 Surveillance Definitions for

Specific Types of Infections

• Non-Catheter-associated Urinary Tract Infection

(Non-CAUTI) - Patient has at least one of the ff:

fever, suprapubic tenderness, costovertebral angle

pain or tenderness, urinary frequency, urinary

urgency, dysuria AND has a urine culture with no

more than two species of organisms identified, one

of which is a bacterium of ≥105 CFU/ml.

• Catheter-associated UTI (CAUTI): A UTI where an

indwelling urinary catheter was in place for >2 days

or the day before AND patient has clinical signs and

symptoms of UTI AND has a urine culture with no

more than two species of organisms identified, one

of which is a bacterium of ≥105 CFU/ml.

Sample Case Definition: Outbreak of

Hospital-acquired Pneumonia

Person

Place

Time

Components of

Case DefinitionHospital-acquired Pneumonia

• Occurring after admission to ward A

• During May-August 2016

• New/progressing abnormalities on chest imaging test AND new onset or worsening purulent sputum/cough, or dyspnea or tachypnea AND positive culture of blood or resp. specimens

5. Find cases systematically

and develop line listing

• How do you find cases?

– Microbiology data

– Infection control or surveillance records

– Discussions with clinicians

– Pharmacy records

– Medical records

– Nursing charts

– Pathology reports

Develop Line Lists

• Line list - used to summarize information

• What to put on a Line List

– Demographic information (age, sex,

occupation, hospital numbr, date of

admission, date of surgery, etc)

– Clinical Data: Signs and Symptoms, Onset

dates and/or times, Outcomes, Lab results,

Antimicrobials, other Medications

– Exposure information : procedures or

surgery; medical devices or equipment

– Other potentially relevant data

Sample Line List from an Investigation

of Acute gastroenteritis

• Don’t get bogged down with case

definitions and capturing all cases

• Goal of Outbreak investigation is

NOT to find and describe every case

• Goal is to STOP THE OUTBREAK –

do not need to find every case

6. Perform Descriptive epidemiology

and develop hypotheses

• Examine the distribution of a disease in a

specific or defined population (“at-risk

population”)

• Describe the basic features of its

distribution in terms of Person, Place,

Time

• Assess Time-trend: Point source,

propagated or circulating, recurrent or

cyclical, seasonal, combination

• Conduct surveillance

Surveillance• Defined as: “The ongoing, systematic

collection, analysis, interpretation, and

dissemination of data regarding a health-

related event for use in public health

action to reduce morbidity and mortality

and to improve health.’’

• Basic components of a surveillance

system:

– Data collection

– Procedure for evaluating data and making

comparisons

– A means for disseminating the resultsCenters for Disease Control and Prevention. Updated guidelines for evaluating public health surveillance systems:

recommendations from the guidelines working group. MMWR 2001;50:1-35.

Retrospective Surveillance

• Retrospective surveillance

– Comprehensive review of sequential

events in the medical records and

examination of information even after

patient is discharged

– Avoids time-consuming efforts of

locating and reviewing charts

– Disadvantage: does not permit

interactions with ongoing caregivers or

verifying data collected

Active Surveillance

• Prevalence study (Cross-sectional study)

– Identify all patients with HAI hospitalized at a

given point time in the entire hospital, or on

selected units.

– Useful for conducting initial assessment of

current issues, before proceeding to a more

focused continuing active surveillance

programme.

– Outcome measure is a Prevalence Rate.

Active Surveillance

• Incidence study (Prospective, longitudinal)

– Detect new cases during the surveillance period

– Preferable if data can be collected regularly and patient

is still under the care of the institution

– Able to capture information in real time, interview

patient’s caregivers, interactively obtain or observe

findings that may not be recorded in the patient record

– More effective in detecting differences in infection

rates, to follow trends, to link infections to risk factors,

and for inter-hospital and inter-unit comparisons

– Outcome measure are Incidence rates, Attack rates,

and Infection ratio

Prevalence Study (Cross-sectional study)

Patient A

Patient B

Patient C

Patient D

Patient E

Patient F

Patient G

Patient H

Point Prevalence- assess

only HAIs active on the day

of the survey

7 days

Period Prevalence- include HAIs active on

the day of the survey and those active during

a predefined period before the survey day

Exercise: Compute HAI Prevalence rate

Patient A

Patient B

Patient C

Patient D

Patient E

Patient F

Patient G

Patient H

7 days

Point Prevalence2/8

(25%

)

Period Prevalence 5/8

(62.5%)

Incidence Study (Prospective)

Patient A

Patient B

Patient C

Patient D

Patient E

Patient F

Patient G

Patient H

Incidence of HAI2/8

(25%)

4 weeks

Epidemic Curves

• Graph used to depict the time

course of an outbreak or epidemic

• Provides a simple visual display of

the outbreak's magnitude and time

trend

• Graphs the number of cases by date

or time of onset of illness.

• Suggests type of exposure or time

of exposure

Time of Exposure is Possible if

Agent is known

Zack Moore, MD, MPH, Medical Epidemiologist. North Carolina Division of Public Health

Zack Moore, MD, MPH, Medical Epidemiologist. North Carolina Division of Public Health

Possible Agent can be Identified if

Exposure Time is known

Epidemic Curves

Environmental Sampling

• Vital part of investigation

• Should be done with (not instead of)

epidemiologic investigation

• Ideally, epidemiologic results guide sample

collection – should not be taken randomly

• Can support epidemiologic findings

• Positive or negative results can be misleading or

difficult to interpret (consider contamination)

• Understand limitations

Environmental and personnel culturing should NOT be

the first step in any outbreak investigation!

Calculation of HAI Rates

• The frequency of infection can be estimated by

prevalence and incidence rates

• Rates are obtained by dividing a numerator by a

denominator

• Numerator - event of interest which can be:

– number of infections

– number of infected patients observed

• Denominator - can be any of the following:

– Total population in which the event may occur (at-risk

population)

– Number of patient-days of risk

Ducel G et al. Prevention of hospital-acquired infections. A practical guide. WHO Geneva 2002.

Ways to Calculate HAI Rate

• Prevalence rate (%)

– Number of patients with HAI (total or specific

infection) at the time of study divided by

Total number of patients observed or exposed

at the same time X100

• Cumulative Incidence rate (Attack rate)

– Number of new infections acquired in a period

divided by Total number of patients observed

or exposed at the same time X100

Lee TB et al. . Recommended practices for surveillance: APIC,Inc.Am J Infect Control

2007;35:427-40; Ducel G et al. Prevention of hospital-acquired infections. A practical guide.

WHO Geneva 2002 .

Ways to Calculate HAI Rate

• Risk Adjusted Infection Rates – rates are

expressed in terms of specific exposures

rather than using an overall census

denominator.

– Incidence rate PER PATIENT-DAYS: number

of new HAI pooled throughout the month(s)

divided by the patient-days of stay x 1000

– Incidence rate PER DEVISE DAYS: number of

new HAI pooled throughout the month(s)

divided by the device-days x 1000 (e.g.

catheter days)

Lee TB et al. . Recommended practices for surveillance: APIC,Inc.Am J Infect Control

2007;35:427-40; Ducel G et al. Prevention of hospital-acquired infections. A practical guide.

WHO Geneva 2002 .

Exercises

Calculate the Surveillance rate for the following:

6.2

1. Nosocomial sepsis rate (Prevalence rate)

No. of At-risk patients in one

month (newly admitted

patients + patients carried

over from previous month)

No. of sepsis

cases

Prevalence Rate (%)

(no. of sepsis cases ÷ no.

at-risk patients)

242 15

1.6

2. Procedure-specific SSI rate (Incidence rate)

No. of cesarean section

operations in one month

Total No. of New

Skin/Soft tissue

infection

Incidence Rate (%)

(no. of new SSI ÷ no. of

cesarean sec performed)

122 2

Exercises

4. Ventilator-associated pneumonia rate (Incidence rate per

device days)

No. of ventilator

days in pediatric

ICU

No. of ventilator-

associated

pneumonias in

pediatric ICU

Rate per 1000

ventilator days (no. of

ventilator-associated

pneumonias ÷ no. of

ventilator days x 1000)

801 5

Calculate the Surveillance rate for the following:

6.2

3. Urinary tract Infection (Incidence rate per patient-days)

Total patients-days of stay

during specified time

period)

No. of

UTI cases

Rate per 1000 patient-

days (number of UTI ÷total patient-days x

1000)

989 11 11.1

Hypothesis Formulation

• Formulate hypothesis to explain the

observed increase in incidence

• Look into associations

• Formulate a hypothesis on the type

of infection (exogenous,

endogenous)

• Tentatively identify the source and

route of infection

7. Evaluate hypotheses and perform

additional studies as necessary

• Test hypothesis about the relationship of a

disease to a specific cause

• Determine Cause-effect relationship by

conducting an epidemiologic study that relates

the exposure of interest to the outcome of

interest

• Typical study designs: cohort, case-control,

experimental design

• Determine the appropriate approach to

surveillance depending on the issue being

surveyed and available resources

Analytical Epidemiologic

Studies• Cohort Studies (prospective or

retrospective)

– Include everyone who could have been

exposed

– A cohort study is feasible only when the

population is well defined and can be followed

over a period of time.

• Case-Control Studies (retrospective)

– Compare exposures among ill persons (case-

patients) and non-ill persons (controls)

Sample Study: Cohort

Risk Ratio = Risk in exposed group/ Risk in

unexposed group

Calculation: [a/a+b) ÷ c/c+d]

Ex. (25/53) ÷ (2/28) = 0.47/0.07 = 6.7

Interpretation: Exposed persons were 6.7x more

likely to develop HAI than those unexposed

HAI Cases No HAI

(Control)

total

Exposure 25 (a) 28 (b) 53

No exposure 2 (c) 26 (d) 28

Total 27 54 81

Sample Study: Case-Control

Odds Ratio: (No. exposed cases x No.unexposed

controls) divided by (No. exposed controls x

No.unexposed cases)

Calculation: [ad/ bc]

Example: 25x26/28 x 2 = = 650/56 = 11.6

Interpretation : Persons exposed had 11.6 times the

odds of developing HAI than persons not exposed

HAI Cases No HAI

(Control)

total

Exposure 25 (a) 28 (b) 53

No exposure 2 (c) 26 (d) 28

Total 27 54 81

Analytic Studies

• Can be useful for supporting your

hypothesis if no obvious source

identified

• Not always necessary

• Time consuming and challenging

• Small number of cases limits power


• Implement control measures to control the

outbreak

• Can occur at any point during outbreak

• Isolation, cohorting, drug or product recall

• Balance between preventing further

disease and protecting credibility and

reputation of institution

• Should be guided by epidemiologic results

in conjunction with environmental

investigation

Break the Chain of Infection

… stop the spread of Infectious

diseases

Hepatitis C Outbreak in Nevada

Endoscopy Center, 2008

• Potentially exposed > 50,000 patients to Hepatitis C and other infectious diseases; 8 acute hepatitis C cases linked directly, 10 hepatitis C cases possibly linked

• Identified breaches contributed to transmission:

– Reuse of syringes for more than one patient

– Reuse of single use vials of propofol for multiple patients

– Poor hand hygiene practicesMMWR May 16, 2008 / 57(19);513-7

General Infection Control Practices

that Prevent Nosocomial Infections

• Hand hygiene

• Standard (universal) precautions

• Isolation precautions : contact, droplet, and

airborne spread

• Environmental cleaning and disinfection

• Disinfection and sterilization of medical devices

and patient care equipment

• Enhanced healthcare provider education and

training

• Cohorting patients or staff

• Maintain adequate staffing levels

Siegel JD, et al. HICPAC 2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents

in Healthcare Settings, June 2007 ; Pittet D, et al Lancet Infect Dis 2006; 6:641.; Haley RW et al. Am J Epidemiol

1985; 121:182.; Whitehouse JD et al.. Compr Ther 1998; 24:71.

Sample Control measures

for Outbreak Management

Ducel G et al. Prevention of hospital-acquired infections. A practical guide. WHO Geneva 2002


• During the investigation of an outbreak, timely,

up-to-date information must be communicated to

the hospital administration, department or unit,

and in some cases, to the public.

• Develop a means for disseminating the results to

those who have a need to know (those involved

in improving those outcomes).

• Include measures to prevent such outbreaks in

the future.

• Media attention desirable if public action needed

Write the Final Report

• A final report on the outbreak

investigation should be prepared

• It should describe the outbreak,

interventions, and effectiveness, and

summarize the contribution of each team

member participating in the investigation.

• It should also make recommendations to

prevent future occurrence.

• This report can be in the medical

literature, and may be considered as a

legal document.


• Follow-up investigation to determine if

there are additional case-patients

• Decide if outbreak is over

• Document effectiveness of control

measures

• Determine if the outbreak has spread

outside its original area or the area where

the interventions were targeted.

Exercise:

Outbreak

Investigation of

HAI

Example of a Hospital

Outbreak Investigation

• March 25, 2017, a report was received that there

were 12 cases of neonatal sepsis in the Neonatal

intensive Care Unit (NICU).

• The first case was reported on March 4:

Klebsiella pneumoniae was isolated from a

preterm baby with severe respiratory distress.

• Within a period of three weeks from the day the

first case was reported, 11 neonates developed

culture proven K. pneumoniae septicemia.

• Nine of the 12 (7 male, 5 female) septicemic

neonates were preterm (75% preterm), 3 were

fullterm.

Example #1

• First clinical manifestation occurred at a mean of

4.8 + 0.43 days after admission (range 3-10days).

• Main presenting complaint: respiratory distress

associated with lethargy and feeding difficulties.

• Disseminated intravascular coagulation (DIC)

seen in 6 neonates

• Necrotizing enterocolitis (NEC) seen in 3

neonates

• Deaths: 10 deaths due to septic shock (83%).








hypotheses


necessary




Is there an Outbreak?

MonthTotal No. of

NICU patients

No. of

HCAI

HCAI

nosocomial)

infection)

Rate

January

2017 148 6 4.05%

February

2017 145 4 2.75%

March

2017 150 12 8.0%






Verify the diagnosis

• Review existing data

– Medical records/charts

– Surveillance records

– Microbiology

– Other Laboratory reports and records

• Interview unit medical/clinical

personnel and paramedical staff

• Clinical observations

Case Definition: Outbreak of

Sepsis (Bloodstream Infection)

Person

Place

• Patient ≤ 1 year of age has at least one of the ff SSx : fever (>38.0oC), hypothermia (<36.0oC), apnea, or bradycardia AND K. pneumoniaeidentified from blood is not related to an infection at another site

Time

Components of

Case Definition

Lab-Confirmed Bloodstream

Infection Criteria (LCBI)

• Occurring after admission to the NICU

• During March 1-31, 2017







Example #1: List of Patients with Klebsiella

pneumoniae Nosocomial Sepsis

Px AOG DOB Date of

onset

Umbilic

cannula

Mech.

Vent

NGT NEC DIC Died

1 Preterm 2/25/17 3/4/17 Y N Y Y N N

2 Fullterm 2/27/17 3/8/17 Y N N N Y Y

3 Fullterm 2/28/17 3/8/17 Y N N N N N

4 Preterm 2/28/17 3/10/17 Y Y Y N N Y

5 Preterm 2/28/17 3/10/17 N Y N N N Y

6 Preterm 3/3/17 3/10/17 Y Y N N N Y

7 Preterm 3/5/17 3/12/17 Y Y N N N Y

8 Fullterm 3/6/17 3/12/17 N N N N Y N

9 Preterm 3/9/17 3/14/17 Y Y N N Y Y

10 Preterm 3/20/17 3/24/17 Y Y N N Y Y

11 Preterm 3/21/17 3/25/17 Y Y N Y Y Y

12 Preterm 3/22/17 3/25/17 Y Y N Y Y Y








hypotheses

Example #1:

Epi Curve of NICU Outbreak

Point Source Epidemic

curve – suggests same

source over a relatively

brief period

What do we know about Klebsiella

pneumoniae sepsis?

• Klebsiella pneumoniae has been incriminated in

hospital acquired infections.

• This organism colonizes the bowel and skin and

is probably transmitted via medical staff hands.

• Nosocomial K. pneumoniae infection is

associated with a high mortality in neonates and

antimicrobial therapy in infections has been

complicated by the emergence of multi-resistant

strains.

Example #1: NICU admissions and

staffing• Average number of monthly NICU admissions: 145 (range

135 – 155)

• At any one time, there are 12-20 neonates requiring

mechanical ventilation

• Nurse staffing has always been a problem, as shown

below:

Level of Care Nurse-to-patient Ratio

Actual Optimal*

Newborns requiring only routine care 1:12-15 1:6- 8

Newborns in transition/ req close

observation

1:6-8 1:4

Newborns requiring intermediate care 1:6-8 1: 2-3

Newborns requiring intensive care 1:4 1: 1-2

*AAP and American College of Obstetricians Gynecologists. (2012). Guidelines for Perinatal Care, 7th Edition. Elk

Grove Village, IL; National Association of Neonatal Nurses. Position Statement #3009. Minimum RN Staffing in

NICUs. Revised July 2008.

Example #1: Environmental

Surveillance Culture Results

• Environmental surveillance cultures

identified the isolates to be the

following:

Bacterial Isolate Location

Klebsiella pneumoniae Ventilator tubings and rinsing

bottles

2 out of 6 sinks sampled in the high

risk area

Coagulase negative

Staphylococcus

2 Feeding cups out of 10 sampled

Enterobacter sp. 1 incubator out of 10 in the high risk

area

Example #1: Hypothesis on Possible

Sources of InfectionPotential exposure or

Source

Examples

Contaminated Medical

Device

ventilator tubings, suction tubings. Intravascular

lines (central or peripheral), umbilical cannula

Contaminated patient

care materials or

equipment

Drugs, IV fluids, thermometers, breastmilk

collection and storage equipment, feeding bottles

or feeding cups; malfunction of disinfection

/sterilization machines

Improper Procedures

or techniques

Improper handwashing and hand hygiene

procedures; Inadequate aseptic techniques in

intubation, suctioning, etc;

Environment inadequate or improper cleaning and

disinfection/sterilization ; contaminated or

ineffective disinfectants

Staffing High nurse-to-patient ratio; crossing of nurses

between ‘clean” and “infected” areas

Others Contaminated breastmilk

Others?








hypotheses


necessary


Case #1: What are the Infection

Control Measures recommended to

control this outbreak?Recomendations Yes or No

Hand hygiene

Standard (universal) precaution

Isolation precautions : contact, droplet, and airborne

spread

Environmental cleaning and disinfection

Disinfection and sterilization of medical devices and

patient care equipment

Enhanced healthcare provider education and training

Cohorting patients

Maintain adequate staffing levels

Others:

e.g. Closing of unit

Ye

s

Ye

s

Ye

s

Ye

s

Ye

s

Ye

s

Ye

s

Ye

s

Ye

s








hypotheses


necessary




Important Points

• Epidemiologic investigations are

essential to determine source of

outbreaks

• Be systematic, consider each step

• Follow the steps if appropriate

• Multiple steps may happen at once

• Might need to repeat steps