Antibiotic Resistance among invasive pneumococcal Isolates from Southwest Sweden 1998-2001
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Antibiotic Resistance among invasive pneumococcal Isolates from Southwest Sweden 1998-2001 All isolates (827 patients) 17,8% 8,6% 8,5% 14,3% Other 9V 9N 8 7F 6B 6A 4 3 23F 19A 14 12F 1 61 isolates with elevated MIC 12,5% 15,6% 7,8% 7,8% 43,8% Other 9V 6B 19F 19A 14 1 Erik Backhaus 1 , Birger Trollfors 2 , Stefan Berg 2 , Berndt EB Claesson 1 , Rune Andersson. 1 . 1 Department of Infectious Diseases and Clinical Microbiology, Kärnsjukhuset, Skövde, 2 Department of Paediatrics, The Queen Silvia Children's Hospital, Göteborg,SwedenCorrespondence: [email protected] ter at the 15 th ECCMID, April 2-5 2005, Copenhagen The abstract has been slightly revised with addition of new data. Objectives 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. Methods 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 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%). 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). 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. Antibiotic agent Total Sensitive Indeterminate Resistant numberbreakpoint** number number breakpoint** Penicillin G 827 805 < 0.06 mg/L 22(2.7%) 0 >1.0 mg/L Erythromycin 827 797 < 0.5 mg/L n.r.* 30 (3.6%) >0.5 mg/L Clindamycin 827 821 < 2 mg/L n.r.* 6 (0.7%) >2 mg/L Tetracycline 827 811 < 2 mg/L n.r.* 16 (1.9%) >2 mg/L Moxifloxacin 827 826 < 0.5 mg/L n.r.* 1 (0.1%) >0.5 mg/L Trim/Sulfa 1/19*** 827 815 < 16 mg/L 21(2.5%) 0 >32 mg/L ** 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. *not relevant Number of S, I and R to six antibiotics stribution of MIC values for 827 invasive strains of Streptococcus pneumoniae Distribution of MIC’s Serotype distribution Sensitivity pattern and serotypes E-test Penicillin G Erythromycin Clindamycin Moxifloxacin Trimethoprim/sulphamethoxazole MIC (mg/L) ,500 ,380 ,250 ,190 ,125 ,094 ,064 Number 400 300 200 100 0 256 128 64 48 32 24 16 12 S R MIC (mg/L) 256 ,500 ,380 ,250 ,190 ,125 ,094 ,064 Number 400 300 200 100 0 S R S ensitivity pattern num ber serotypes (no ofisolates) S ensitive to alltested substances 766 IorR to any substance 61 -IorR to only one substance 40 P enicillin G (I) 3 19A (1),19F(2) E rythrom ycin (R ) 24 14(24) Tetracycline (R ) 6 several Trim /S ulfa (I) 6 several M oxifloxacin (R ) 1 1 -IorR to m ore than one substance 21 P cG (I)+T/S (I) 11 9V (8),14(2),6B (1) P cG (I)+Tet(R ) 2 14(1),19F(1) P cG (I)+Tet(R )+T/S (I) 2 6A (1),19A (1) P cG (I)+E ry (R )+C lin(R )+Tet(R ) 2 6B (1),14(1) P cG (I)+E ry (R )+C lin(R )+Tet(R )+T/S (I) 2 19F(2) E ry (R )+C lin(R )+Tet(R ) 2 6B (1),14(1) Total 827 61 Tetracycline MIC (mg/L) ,750 ,500 ,380 ,250 ,190 ,125 ,094 ,064 Number 500 400 300 200 100 0 48 32 24 16 8 4 2 6 3 1,5 S R 1 12 64 MIC (mg/L) 1 ,75 ,50 ,380 ,250 ,190 ,125 ,094 ,064 ,047 ,032 ,023 ,016 ,012 ,008 ,006 Number 400 300 200 100 0 S I R 1,5 2 MIC (mg/L) 8 ,380 ,250 ,190 ,125 ,094 ,064 ,047 Number 500 400 300 200 100 0 S R MIC (mg/L) 32 8 6 4 3 2 1,500 1,0 ,75 ,50 ,380 ,250 ,190 ,125 ,064 Number 400 300 200 100 0 S I R 48 64 Antibiotic agent MIC 50 MIC 90 median 90 percentile mg/L mg/L Penicillin G 0.016 0.023 Erythromycin 0.190 0.250 Clindamycin 0.190 0.250 Tetracycline 0.125 0.190 Moxifloxacin 0.125 0.190 Trim /Sulfa 1/19*** 0.5 1
description
Antibiotic agent. MIC 50. MIC 90. 1. Other. 1. median. 90 percentile. Other. 12,5%. 14,3%. mg/L. mg/L. 17,8%. 12F. Penicillin G. 0.016. 0.023. 9V. 9V. 8,6%. Erythromycin . 0.190. 0.250. 14. 15,6%. 8,5%. Clindamycin . 0.190. 0.250. 43,8%. 9N. 14. 19A. Tetracycline . - PowerPoint PPT Presentation
Transcript of Antibiotic Resistance among invasive pneumococcal Isolates from Southwest Sweden 1998-2001
Antibiotic Resistance among invasive pneumococcal Isolates from Southwest Sweden 1998-2001
All isolates (827 patients)
17,8%
8,6%8,5%
14,3%
Other
9V
9N
8
7F
6B
6A
4
3
23F
19A
14
12F
1
61 isolates with elevated MIC
12,5%
15,6%
7,8%
7,8%
43,8%
Other
9V
6B
19F
19A
14
1
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]
Poster at the 15th ECCMID, April 2-5 2005, Copenhagen
The abstract has been slightly revised with addition of new data.
ObjectivesStreptococcus 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.
MethodsAll 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.
Results827 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%).
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).
ConclusionThe 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.
Antibiotic agent Total Sensitive Indeterminate Resistant
number breakpoint** number number breakpoint**
Penicillin G 827 805 <0.06 mg/L 22(2.7%) 0 >1.0 mg/L Erythromycin 827 797 <0.5 mg/L n.r.* 30 (3.6%) >0.5 mg/LClindamycin 827 821 <2 mg/L n.r.* 6 (0.7%) >2 mg/LTetracycline 827 811 <2 mg/L n.r.* 16 (1.9%) >2 mg/LMoxifloxacin 827 826 <0.5 mg/L n.r.* 1 (0.1%) >0.5 mg/LTrim/Sulfa 1/19*** 827 815 <16 mg/L 21(2.5%) 0 >32 mg/L
** 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.
*not relevant
Number of S, I and R to six antibiotics
Distribution of MIC values for 827 invasive strains of Streptococcus pneumoniae
Distribution of MIC’s Serotype distribution
Sensitivity pattern and serotypes
E-test
Penicillin G Erythromycin Clindamycin Moxifloxacin Trimethoprim/sulphamethoxazole
MIC (mg/L)
,500
,380
,250
,190
,125
,094
,064
Num
ber
400
300
200
100
0256
128
64
48
32
24
16
12
S R
MIC (mg/L)
256,500,380,250,190,125,094,064
Num
ber
400
300
200
100
0
S R
Sensitivity pattern number serotypes (no of isolates)
Sensitive to all tested substances 766
I or R to any substance 61
- I or R to only one substance 40 Penicillin G (I) 3 19A(1), 19F(2) Erythromycin (R) 24 14(24) Tetracycline (R) 6 several Trim/Sulfa (I) 6 several Moxifloxacin (R) 1 1
- I or R to more than one substance 21 PcG (I)+T/S (I) 11 9V(8), 14(2), 6B(1) PcG (I)+Tet (R) 2 14(1), 19F(1) PcG (I)+Tet (R)+T/S (I) 2 6A(1), 19A(1) PcG (I)+Ery (R)+Clin(R)+Tet (R) 2 6B(1), 14(1) PcG (I)+Ery (R)+Clin(R)+Tet (R)+T/S (I) 2 19F(2) Ery (R)+Clin(R)+Tet (R) 2 6B(1), 14(1)
Total 827 61
Tetracycline
MIC (mg/L)
,750
,500
,380
,250
,190
,125
,094
,064
Num
ber
500
400
300
200
100
0
48
32
24
16842
631,5
S R
1
12
64
MIC (mg/L)
1
,75
,50
,380
,250
,190
,125
,094
,064
,047
,032
,023
,016
,012
,008
,006
Num
ber
400
300
200
100
0
S I R
1,5
2
MIC (mg/L)
8,380,250,190,125,094,064,047
Num
ber
500
400
300
200
100
0
S R
MIC (mg/L)
32
8
6
4
3
2
1,500
1,0
,75
,50
,380
,250
,190
,125
,064
Num
ber
400
300
200
100
0
S I R
4864
Antibiotic agent MIC 50 MIC 90median 90 percentilemg/L mg/L
Penicillin G 0.016 0.023Erythromycin 0.190 0.250Clindamycin 0.190 0.250Tetracycline 0.125 0.190Moxifloxacin 0.125 0.190Trim /Sulfa 1/19*** 0.5 1
