Transcript PowerPoint-presentation

Poster at the 15th ECCMID, April 2-5 2005, Copenhagen
Antibiotic Resistance among invasive pneumococcal Isolates from Southwest Sweden 1998-2001
Erik Backhaus1, Birger Trollfors2, Stefan Berg2, Berndt EB Claesson1, Rune Andersson. 1. 1Department of Infectious Diseases and Clinical Microbiology, Kärnsjukhuset, Skövde, 2Department of Paediatrics, The Queen Silvia Children's Hospital, Göteborg,SwedenCorrespondence:
[email protected]
The abstract has been slightly revised with addition of new data.
E-test
Distribution of MIC’s
Serotype distribution
Objectives
61 isolates with elevated MIC
Antibiotic agent
Streptococcus pneumoniae is a major human pathogen. In
Southwest Sweden, with a population of 1.8 million, 200 patients are
diagnosed each year with invasive pneumococcal disease. The rapid
emergence of isolates with decreased susceptibility to several
antibiotics is an increasing problem in many parts of the world. The
aim of the present study was to investigate the pattern of
susceptibility among invasive isolates, in order to see if the current
treatment policies are appropriate, and to see if there seems to be a
trend of increasing antibiotic resistance.
MIC 50
median
mg/L
0.016
0.190
0.190
0.125
0.125
0.5
Penicillin G
Erythromycin
Clindamycin
Tetracycline
Moxifloxacin
Trim /Sulfa 1/19***
MIC 90
90 percentile
mg/L
0.023
0.250
0.250
0.190
0.190
1
All isolates (827 patients)
827 invasive strains were tested. Of these, 766 were fully
susceptible and 61 (7.4%) were classified as Indeterminate (I) or
Resistant (R) for any of the tested antibiotics, according to the
Swedish Reference Group for Antibiotics system of species related
breakpoints. No isolate had a MIC>1.0 mg/L against penicillin (R).
22 isolates (2.7%) were classified as I to penicillin (MIC >0.06, 1.0
mg/L). 13 of them had MIC’s  0.5 mg/L. Among the 22 isolates
classified as I to penicillin 12 isolates were also I against cefotaxime
(MIC >0.12, 1.0 mg/L) (1.5%).
1
Other
1
Other
12,5%
17,8%
14,3%
12F
9V
9V
8,6%
15,6%
43,8%
8,5%
14
9N
14
19A
7,8%
8
23F
6B
7F
3
19F
7,8%
6B
4
19A
6A
Methods
Sensitivity pattern and serotypes
Number of S, I and R to six antibiotics
All clinical isolates of S. pneumoniae from blood, cerebrospinal and
joint fluid were collected at the laboratories in Göteborg, Skövde,
Borås, Uddevalla and Halmstad during 1998-2001. The MIC-values
for seven commonly used antibiotics (penicillin G, erythromycin,
clindamycin, tetracycline, moxifloxacin, cotrimoxazole and
cefotaxime) were determined with E-test (AB Biodisk) according to
standard methods.
Results
Antibiotic agent
Total
Penicillin G
Erythromycin
Clindamycin
Tetracycline
Moxifloxacin
Trim/Sulfa 1/19***
827
827
827
827
827
827
Sensitive
Indeterminate
Sensitivity pattern
Resistant
number
breakpoint**
number
number
805
797
821
811
826
815
<0.06 mg/L
<0.5 mg/L
<2 mg/L
<2 mg/L
<0.5 mg/L
<16 mg/L
22(2.7%)
n.r.*
n.r.*
n.r.*
n.r.*
21(2.5%)
0
30 (3.6%)
6 (0.7%)
16 (1.9%)
1 (0.1%)
0
number
Sensitive to all tested substances
breakpoint**
*not relevant
** Species related breakpoints according to the Swedish Reference Group for Antibiotics system.
*** Values on the MIC scale refer to the first component of the combination.
serotypes (no of isolates)
766
I or R to any substance
>1.0 mg/L
>0.5 mg/L
>2 mg/L
>2 mg/L
>0.5 mg/L
>32 mg/L
The other tested antibiotics showed the following results:
Erythromycin R (MIC >0.5 mg/L) 30 isolates (3.6%), clindamycin R
(MIC>2 mg/L) 6 isolates (0.7%), tetracycline R (MIC>2mg/L) 16
isolates (1,9%), and moxifloxacin R (MIC>0,5 mg/L) 1 isolate (0.1%).
There were no isolates classified as I for those antibiotics. There
were 21 isolates (2,5%) classified as I against cotrimoxazole (MIC
>16, 32 mg/L), but no R (MIC>32 mg/L).
61
- I or R to only one substance
Penicillin G (I)
Erythromycin (R)
Tetracycline (R)
Trim/Sulfa (I)
Moxifloxacin (R)
40
- I or R to more than one substance
PcG (I)+T/S (I)
PcG (I)+Tet (R)
PcG (I)+Tet (R)+T/S (I)
PcG (I)+Ery (R)+Clin(R)+Tet (R)
PcG (I)+Ery (R)+Clin(R)+Tet (R)+T/S (I)
Ery (R)+Clin(R)+Tet (R)
21
Total
3
24
6
6
1
19A(1), 19F(2)
14(24)
several
several
1
11
2
2
2
2
2
9V(8), 14(2), 6B(1)
14(1), 19F(1)
6A(1), 19A(1)
6B(1), 14(1)
19F(2)
6B(1), 14(1)
Conclusion
The proportion of invasive isolates of pneumococci with decreased
sensitivity to commonly used antibiotics is very low.
Our results indicate that there might be a clonal spread of isolates of
serotype 9V and 14 with reduced susceptibility to antibiotics.
827 61
Distribution of MIC values for 827 invasive strains of Streptococcus pneumoniae
Erythromycin
Penicillin G
Clindamycin
Tetracycline
400
S
400
I
R
S
400
S
R
R
S
500
Trimethoprim/sulphamethoxazole
Moxifloxacin
500
R
S
R
S
400
I
R
400
400
300
300
0
0
,006
,012
,008
,023
,016
,047
,032
,094
,064
MIC (mg/L)
,190
,125
,380
,250
,75
,50
1
2
200
200
100
100
Number
300
,125
,094
,250
,190
,500
,380
16
12
MIC (mg/L)
32
24
64
48
256
200
100
0
0
,064
1,5
300
100
100
100
200
Number
200
Number
200
300
Number
Number
Number
300
,064
,094
,125
,190
,250
,380
,500
256
,125
,094
128
MIC (mg/L)
0
0
,064
,250
,190
,500
,380
1
,750
2
1,5
4
3
MIC (mg/L)
16
8
6
12
64
32
24
,047
,064
,094
,125
,190
48
,250
,380
8
,064
,190
,125
MIC (mg/L)
,380
,250
,75
,50
1,500
1,0
3
2
MIC (mg/L)
6
4
32
8
64
48