Methicillin resistant Staphylococcus aureus (MRSA)

in the Nordic countries

Petter ElstrømAdvisor

Norwegian Institute of Public Health

Objective

Prevent establishment of MRSA in hospitals

• Increased rate of MRSA enforce changes in empiric treatment of S. aureus-infections

• Changes in antibiotic-guidelines will lead to more resistant bacteria and increase the cost

Historical overview • Penicillin G introdused in 1941• Penicillin resistant (-lactamase prod.) S.aureus isolated

in 1942• Meticillin introdused in 1959 as the first -lactamase resistant penicillin• Meticillin resistant S.aureus first described in 1961• In late sixties MRSA was identified as a nosokomial

pathogen • In late nineties reduced sensitivity against Vancomycin

(VISA) was reported • Vancomycin resistant S.aureus (VRSA) isolated in 2002

First ”MRSA-wave”• Meticillin resistant first described in 1961• Worldwide spread of a single arcaic clone

Second “MRSA-wave”• Outbreaks in hospitals• 5 dominant clones

Third “MRSA-wave”• CA-MRSA• Evolution of ”old” clones• Continually new MRSA-strains discovered

Historical overview

CA-MRSA

• Both epidemiological and microbiological definition

• Increased incidence among people outside hospitals• Young people with no known risk factors for MRSA

• Differ genetically from strains inside hospitals– SCCmec IV, PVL

• Less resistant• Mainly skin- and soft tissue infections Occasionally

severe infections (necrotizing pneumonia)

Changed epidemiology

• Earlier:– Imported cases

– Related to hospital admission or employment

• Now:– Most domestic cases

– Increasing rate of cases not related to hospitals

– Often no known risk factors for MRSA

– Outbreaks in nursing homes

MRSA in western Europe

Source: www.earss.rivm.nl

Proportion of invasive isolates resistant to methicillin 2003

MRSA in England og Wales

0

5

10

15

20

25

30

35

40

45

50

Proportion (%) of MRSA i blood culture, 1989-2002

MRSA in the Nordic countries

*Estimated for 2005

Source: http://www.srga.org/SSAC/doc/2005/SSAC_MRSAreport_2004.pdf

0

5

10

15

20

25

30

Year

Inc

ide

nc

e (

No

/10

0.0

00

) Sweden

Finland

Denmark

Norway

Iceland

MRSA in DenmarkDistribution by place of transmission

0

50

100

150

200

250

300

1999 2000 2001 2002 2003 2004

No

. of c

ases

CO-MRSA

HA-MRSA

Imported

Source: Robert Skov, State serum institute, Sept. 2005

MRSA i Danmark

0

5

10

15

20

25

30

35

40

45

<1 1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 >81

Age group

No

. of

ca

se

s

CA-MRSA

HA-MRSA

Distribution by age group, 2003

Source: Robert Skov, State serum institute, Sept. 2005

MRSA in Sweden

Community

Hospital

Primary care

Home for the elderly

Abroad (communityand hospital)

Unknown

S

2003 2004

Source: Otto Cars, Smittskyddsinstitutet, sept. 2005

Distribution by place of transmission

MRSA in NorwayNo. of cases, 1995 – 15.nov. 2005

0

50

100

150

200

250

300

350

400

450

500

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

No

. of

ca

se

s

Infection Colonization

0

2

4

6

8

10

12

14

16

18

20

No

. pe

r 1

00

00

0 2004

15. nov. 05

MRSA in NorwayProportion by county, 2004 - 2005

MRSA in NorwayDistribution by place of transmission

0

20

40

60

80

100

120

140

160

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

No

. o

f ca

ses

Domestic

Imported

Unknown

Hospitalized:

MRSA in NorwayDistribution by place of infection onset

0

20

40

60

80

100

120

140

160

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

No

. o

f ca

ses

Yes

No

Unknown

Reported outbreaks in health care institutions

0

1

2

3

4

5

6

7

2002 2003 2004 2005

Sykehus Sykehjem

MRSA in Norway

2003: 2 hospitals, 3 nursing homes

2004: 2 hospitals, 4 nursing homes

2005: 8 nursing homes

Challenges

• Increasing incidence of MRSA• Changing epidemiology• Bacterial evolution• Laboratorial methods are not optimal• Lack in knowledge• Differs in national and regional guidelines• Compliance of infection control measures are

not optimal

Actions

• Coordinate the guidelines in the Nordic countries • Discuss and coordinate advices and guidelines in

Norway• Better survey through genotyping of all isolates• Continue rational use of antibiotics• Science

• High quality in hygiene and other infection control measures