Surveillance of Healthcare-

Associated Infections

Learning Objectives

1. Explain the purpose or aims of surveillance.2. Discuss how to establish a system for

healthcare-associated infection surveillance.

3. Differentiate between continuous surveillance and periodic prevalence surveys.

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Time involved

• 45 minutes

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What is Surveillance?

The systematic observation of the occurrence and distribution of disease within a population and of the events that increase or decrease the risk of the disease occurrence

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Aims of HAI Surveillance - 1

Identification of problems and prioritising infection prevention and control (IP&C) activities

Assisting the development of IP&C policies and associated clinical practices

Detecting changes in the endemicity of an HAI or an adverse event

Detecting changes in compliance with IP&C policies

Detecting outbreaks of adverse events

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Aims of HAI Surveillance - 2

Establishing the effectiveness of an intervention

Identifying whether the current program meets benchmarks

Establishing data for an evidence-based plan to improve care and to meet accreditation or regulatory requirements

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Establishing a Frameworkfor SurveillanceInfection surveillance framework includes:

Assessing the population Selecting the outcome or process for surveillance Using surveillance definitions Collecting surveillance data Calculating and analyzing surveillance rates Applying risk stratification Reporting and using surveillance information

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Assessment of the Population

Assessment should evaluate:1. High risk populations 2. High volume procedures, interventions 3. High impact infections 4. High cost infections

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Outcome vs. Process

• Outcome Surveillance• Decreasing risk and costs• Identify gaps

• Process Surveillance• Identify care delivery issues

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What to consider in establishing a surveillance framework - 1 Is it necessary to survey the entire health care

facility or only focus on high-risk patient groups or procedures or commonly performed procedures?

Have rates increased in certain groups/procedures /interventions?

What is the most important IP&C-related process that is likely to be associated with this rate?

How will a standard, validated, and reproducible definition of infection be applied?

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What to consider in establishing a surveillance framework - 2 Should continuous surveillance or point

prevalence surveys be used? How will the data be collected, stored, retrieved,

summarized, and interpreted? How will results to clinicians be provided in a

timely manner? How will the information be used to continue to

lower infection rates?

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Types of Surveillance

Continuous surveillance or periodic prevalence surveys

Alert-based surveillance Post-discharge surveillance

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Continuous Surveillance - 1

Undertaken prospectively Best way to establish trends and distribution

of HAI incidence Can be active, passive, or a combination of

both Active surveillance involves daily visits to

patient wards/care units to assess patients at-risk of HAI

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Continuous Surveillance - 2

Case finding using active and passive surveillance by an IP&C practitioner increases correct detection of HAIs

Only incidence cases of HAI should be reported

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Prevalence Surveys

A good substitute for continuous surveillance Performed on a single day or week

Can show the magnitude of HAI, highlight problems requiring more investigation, and identify changing patterns of HAIs

Can be used to target areas or services where infection rates are suspected to be high

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Prevalence Survey: Line listing

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Area: _______________________________________

Month/quarter Year

Resident/patient

Identifiers

HAI

(No=0/Yes=1)

HAI

Name Bed Number Type of HAI Microorganism

Antibiotic

Treatment

Alert-based Surveillance - 1

Monitor specific clinical conditions surgical site infections caused by Group A

Streptococcus meningococcal meningitis

Is a part of the ICP team daily work Aims to warn of early outbreaks and allow rapid

control procedures

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Alert-based Surveillance - 2

Alert organism surveillance Continuous monitoring of specific microorganisms

identified by the microbiology laboratory Simple and cheap, and can be automated in

computerised laboratories Can show trends of specific microorganisms in

different wards over time Allows the IP&C team to formulate preventive

actions

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Post-discharge Surveillance

A method of identifying patients with a HAI after leaving the facility

Often used for surgical site infection (SSI) detection

Will identify more infections and therefore yield a higher SSI rate

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How to Conduct Post-Discharge Surveillance A letter sent home with the patient to

complete and return A questionnaire to the patients’ medical

practitioner

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Definitions for HAI

An infection occurring during the process of care in a health-care facility which was not present or incubating at the time of admission

Includes infections acquired in the health-care facility but appearing after discharge and also occupational infections among health-care workers

A cut-off point 48 hours after admission is typically used to distinguish between HAI and community infections

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What are standards or thresholds for HAI rates? Infection rates vary according to the definition

used Comparisons should only be made if the same

set of definitions is used and applied in exactly the same manner

More meaningful to use surveillance data from same institution to measure trends to alert staff of increasing problems to monitor the effectiveness of interventions

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Surveillance Statistics: Rates

Rates are calculated with a numerator (number of persons with the infection) divided by a denominator (number of persons at risk for the infection)

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Incidence Rate

Incidence rate (%)

No. of patients diagnosed with new HAI during the surveillance period x 100 No. of patients at-risk of HAI during the same period

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Prevalence Rate - 1

• The number of cases of active HAI in a defined patient population

• May be new cases or ones that developed before the survey timeframe and are still active

• Prevalence rate• the proportion of patients in the population who

have an active infection at the time of the survey

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Prevalence Rate - 2

Number of new and existing cases of specific HAI during the specified survey period x 100 Total number of patients surveyed for HAI during the specified survey period

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Incidence Density Rates Based on an accumulation of person-time units with

a statistically rare numerator (e.g., CLABSI) Convention is to multiply the proportion by 1,000 to

be expressed as per 1,000 patient/bed/catheter days

Calculation of Incidence density

number of new specific HAI during the surveillance reporting period x 1000 Person-time of susceptible patients at risk during the same surveillance period

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Utilisation Ratio

Number of devices per number of patient-days A measure of the total patient-days in which a

high-risk device was used Can be used as a marker for risk of infection Calculate the utilisation ratios for each unit with

a denominator that reflects only those patients at-risk

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Calculation of Utilisation Ratio

Urinary catheter utilisation ratio

= Total number of urinary catheter-days Total number of patient-days

Central catheter utilisation ratio

= Total number of central catheter-days Total number of patient-days

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Number device-associated infections for a site x 1,000

Number of device-daysInfection rate per 1,000 device-days

Device-Associated Infection Rates

Catheter-Associated Urinary Tract Infection Rate

Number of catheter-associated UTI x 1000 Number of catheter-days D

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Infection rate of catheter-associated UTI per 1000 catheter-days

Frequency of Data Analysis

Incidence data usually analysed periodically to establish rates

Typically calculated at the end of every month or quarter

Prevalence data analysed immediately at the end of the survey to establish a rate that reflects that survey period

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Summary - 1 There should be a written surveillance plan for the

health care facility including definitions used how data are collected the frequency of data collection who is responsible for surveillance activities

Surveillance activities should support a system that can identify risk factors for infection and other adverse

events implement risk-reduction measures monitor the effectiveness of interventions

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Summary - 2

Surveillance plays a critical role in identifying outbreaks, emerging infectious diseases, antibiotic-resistance organisms, and bioterrorist events so that infection prevention and control measures can be instituted

Surveillance program in healthcare organisations should be integrated to include infection prevention, performance improvement, patient safety and public health activities

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References• Lee TB, et al. Recommended practices for surveillance: Association

for Professionals in Infection Control and Epidemiology (APIC), Inc. Am J Infect Control 2007; 35: 427-440.

• McLaws ML, Taylor P. The Hospital Infection Standardised Surveillance (HISS) programme: analysis of a two-year pilot. J Hosp Infect 2003; 53 (4): 260-268.

• Best Practices for Surveillance of Health Care-Associated Infections, 2008, Ontario Ministry of Health and Long-Term Care/Public Health Division/Provincial Infectious Diseases Advisory Committee, Canada. http://www.health.gov.on.ca/patient_safety/pro/cdad/toolkit_ricn/rep_pidac_hai_best_prac.pdf

• European Centre for Disease Prevention and Control. Surveillance http://www.ecdc.europa.eu/en/activities/surveillance/Pages/Activities_Surveillance.aspx

• VICNISS Hospital Acquired Infection Surveillance System. State Government Victoria, Australia. http://www.vicniss.org.au/

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Epi Info

Epi Info, a free software package can be downloaded from the Centers for Diseases Control and Prevention, http://wwwn.cdc.gov/epiinfo/html/downloads.htm, with a desktop calculator version accessed from http://wwwn.cdc.gov/epiinfo/html/prevVersion.htm.

Alternatively, a free calculator written in Excel is available at www.pedro.org.au/wp-content/uploads/CIcalculator.xls

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Quiz1. The purposes of establishing an HAI surveillance system

include which of the following?a. Identification of HAI problems within an organizationb. Detecting outbreaks of HAIsc. Establishing data for improving patient outcomesd. All of the above

2. Which of these types of surveillance can be used as a substitute for continuous surveillance of HAIs?

a. Post discharge b. Alert based c. Prevalence d. Prospective

3. A written surveillance plan is an important component of the infection prevention and control programme. (T/F).

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International Federation of Infection Control• IFIC’s mission is to facilitate international networking in

order to improve the prevention and control of healthcare associated infections worldwide. It is an umbrella organisation of societies and associations of healthcare professionals in infection control and related fields across the globe .

• The goal of IFIC is to minimise the risk of infection within healthcare settings through development of a network of infection control organisations for communication, consensus building, education and sharing expertise.

• For more information go to http://theific.org/

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