Surveillance of antimicrobial resistance Liselotte Högberg Swedish Institute for Infectious Disease Control E-mail: liselotte.hogberg@smi.ki.se.

Surveillance of antimicrobial resistance

Liselotte Högberg

Swedish Institute for Infectious Disease Control

E-mail: liselotte.hogberg@smi.ki.se

OVERVIEWBasic principles

Why, what, how and who?

Antimicrobial surveillance in Sweden

Different types of surveillance

Validity of surveillance data

Sensitivity, specificity

WHY?

- Defining/updating treatment guidelines

- Identifying needs for infection control measures

- Monitoring the impact of interventions to improve antimicrobial use and control spread of infection

Basic principles

Basic principles

• Should be focused on pathogens of greatest public health importance

• Should include pathogens that are readily transmissible

• Should provide information for action at local and national levels

WHAT?

Basic principles

HOW ?

• Comprehensive surveillance

• Sentinel surveillance

• Point-prevalence studies

Basic principles

Comprehensive surveillance

- Includes the whole population at risk

- Aiming to capture all cases

- Involves large number of clinicians and laboratories – only limited set of data

Basic principles

Sentinel surveillance

- Indicator data for rest of population

- Suitable when prolonged and detailed data is required

- Target approach (instead of representative sample) might be suitable

Basic principles

Point prevalence studies

- Useful for validation of representativity of surveillance data

- Evaluation of interventions

Basic principles

WHO ?

• General population vs. hospital in-patients

• Clinical reports

• Laboratory reports

Basic principles

Clinical data Laboratory data

+ timely information on clinical disease

+ possibility to get detailed patient information

- dependent on accuracy and consistency in diagnosis and timely and complete reporting

+ objective confirmation of the diagnosis

+ opportunity for detailed characterisation of the causative organism

- less timely

- often few clinical details

DATA SOURCE

Numerators for surveillance• Data should relate to a single episode of

illness in a patient

• Microbiological data: only the first positive culture from the patient from each disease episode should be reported

• Microbiological data: qualitative or quantitative

Basic principles

Examples of antimicrobial surveillance projects

ANNUAL REPORTS

DANMAP – Denmark

FIRE – Finland

NORM – Norway

SWEDRES – Sweden

EARSS (www.earss.rivm.nl)

RESEARCH/INDUSTRY INITATIVES

Alexander project

Sentry

Basic principles

Examples of antimicrobial surveillance systems

ANNUAL REPORTS

DANMAP – Denmark

FIRE – Finland

NORM – Norway

SWEDRES – Sweden

EARSS (www.earss.rivm.nl)

RESEARCH/INDUSTRY INTITATIVES

Alexander project

Sentry

Basic principles

AMR surveillance in Sweden

Antimicrobial resistance surveillance in Sweden

1. Mandatory case notification

2. Annual resistance surveillance and quality control programme (RSQC)

3. Sentinel surveillance

4. EARSS

AMR surveillance in Sweden

Antimicrobial resistance surveillance in Sweden

Mandatory case notification

Comprehensive surveillance of all cases of MRSA, VRE and penicillin-resistant pneumococci (PRP) to the Swedish Institute for Infectious Disease Control

Mandatory for both the clinician having seen the patient and the laboratory diagnosing the pathogen

Basic patient data: age, sex, place of residence

Data presented as incidence figures (population denominator)

AMR surveillance in Sweden

Antimicrobial resistance surveillance in Sweden

Annual resistance surveillance and quality control programme (RSQC)Each laboratory report resistance data for at least 100 consecutive bacteria per year

Includes S. pneumoniae, S. aureus, E. coli, S. pyogenes, H. pylori, E. faecalis/faecium

No patient data avilable

Detailed resistance data

Data presented as proportion (% resistant isolates/ all isolates)

AMR surveillance in Sweden

Antimicrobial resistance surveillance in Sweden

Sentinel surveillance

Data mainly derived from special investigations by devoted laboratories

At present includes salmonella, shigella, campylobacter, N. gonorrhoeae, N. meningitidis

Quality of data varies

AMR surveillance in Sweden

Antimicrobial resistance surveillance in Sweden

EARSS

Funded by DG SANCO of the European Commission

Surveillance of antmicrobial susceptibility of invasive infections of S. aureus, S. pneumoniea, E. coli, E. faecalis/faecium

27 countries participates

www.earss.rivm.nl

EARSS: Proportion PRP isolates in year 2000

AMR surveillance in Sweden

INFORMATION FEEDBACK

ResNet (www.srga.org/resnet_sok.htm)

Electronic database containing data from RSQC, EARSS and sentinel surveillance

SwedRes (www.smittskyddsinstitutet.se)

Annual report on Swedish antibiotic utilisation and resistance in human and veterinary medicine

Data validity

PRP (penicillin-resistant pneumococci)

Streptococcus pneumoniae MIC PcG >= 0,5 mg/L

Notifiable in Sweden since 1996

Increasing resistance problem internationally

Surveillance data available from mandatory data, RSQC and EARSS

Data validity

0

1

2

3

4

5

6

7

1997 1998 1999 2000 2001 2002 2003

Year

Incidence/ 100 000 inh (PRP MIC PcG >= 0,5 mg/L)

Data validity

0

1

2

3

4

5

6

7

1997 1998 1999 2000 2001 2002 2003

Year

Incidence/ 100 000 inh (PRP MIC PcG >= 0,5 mg/L)

RSQC rate (PRP MIC >= 0,12 mg/L)

Data validity

0

1

2

3

4

5

6

7

1997 1998 1999 2000 2001 2002 2003

Year

Incidence/ 100 000 inh (PRP MIC PcG >= 0,5 mg/L)

RSQC rate (PRP MIC >= 0,12 mg/L)

EARSS rate (Invasive PRP >= 0,12 mg/L)

Data validity

0

1

2

3

4

5

6

7

1997 1998 1999 2000 2001 2002 2003

Year

Incidence/ 100 000 inh (PRP MIC PcG >= 0,5 mg/L)

RSQC rate (PRP MIC >= 0,12 mg/L)

EARSS rate (Invasive PRP >= 0,12 mg/L)

PRP rate (PRP MIC PcG >= 0,5 mg/L)

Data validity

Nasopharyngeal cultures/1000 inhabitants in Sweden 1998-2003

0

5

10

15

20

25

1998 1999 2000 2001 2002 2003Year

NP

H c

ult

ure

s /

10

00

in

ha

bit

an

ts

Changes in culturing propensity

0

10000

20000

30000

40000

50000

60000

70000

80000

0 2000 4000 6000 8000 10000 12000

S. pneumoniae

Nas

op

har

yng

eal

cult

ure

s

Data validity

Ideal surveillance data

• Maximum specificity– Limit false positives

• Maximum sensitivity– Captures all true positives

– Determination of break-points at laboratories– Transient nasal carriage (MRSA)

Data validity

Specificity

• Methodological problems at the laboratory

• Reporting bias from laboratories

Data validity

Determinants for sensitivity

1. Contact with health care services

2. The pathogen is isolated

3. The case is reported

There is a risk for bias in each step!

Data validity

Contact with health care services

• Accessibility– Better access to physicians in large cities

• Costs– Free health care for children, cost recovery

systems

• Socio - economy, tradition

• Screening/contact tracing initiatives

Data validity

Routines for contact tracing

for PRP

MIC PcG > 0,5 mg/L

Multi-resistance or high MIC-values

Individual

Isolation of the pathogen

• Cultures from all cases/only on therapeutic failures?

• Tradition in culturing propensity

• Economical obstacles

• Fear of time-consuming contact tracing

Data validity

Nasopharyngeal culturing propensity in Sweden 1998-2002

(Number of nasopharyngeal cultures/1000 inhabitants)

Data validity

Who is sampled?

CarriageDiseaseAntibiotic treatment

Treatment failure

Data validity

PRP incidence/1000 inhabitants (all cases) in area G and M

0

5

10

15

20

25

30

35

40

1998 1999 2000 2001 2002

Year

PR

P in

cid

en

ce

/ 1

00

00

0 in

h

G

M

Data validity

PRP incidence (only index cases) in area G and M

0

1

2

3

4

5

6

1998 1999 2000 2001 2002

Year

PR

P i

nc

ide

nc

e /

10

0 0

00

in

h G

M

Data validity

Summary: Basic principles• Obtaining appropriate specimens from

the infected individual• Successful isolation of the causative

organisms• Accurate determination of antimicrobial

resistance• Data collection, collation and analysis• Dissemination of appropriate information

for action

Summary