1. Clinical and Microbiologic Characteristics of Group A Streptococcal Skin and Soft Tissue Infection in Children
謝旻玲1、沈靜芬1,3、蘇榆芳4、李冠賢1,3、何宗憲2、王世敏2、劉清泉1,3
國立成功大學醫學院附設醫院 小兒部1、急診部2、感染控制委員會3、
國立成功大學基礎醫學研究所4

2. Background
Group A streptococcus (GAS) can cause a variety of skin and soft tissue infections (SSTI).
The severity of GAS SSTI ranges from self-limited superficial skin infections, such as impetigo and erysipelas to fatal necrotizing fasciitis.
M protein, fimbrial protein located on the cell surface, is an important virulence factor.

3. Objective
To describe the clinical characteristics and microbiologic features of childhood GAS SSTIs.
To compare clinical and microbiologic differences between GAS SSTIs with different severities.

4. Materials and Methods Study design: retrospective, hospital-based
Study period: 1999 to 2011
Setting: a tertiary medical center
Enrolled criteria: < 18 year-old children with SSTIs and GAS isolated either from pus or blood

5. Definition & Category Superficial SSTI Intermediate SSTI Deep SSTI
Impetigo
Erysipelas
Carbuncle
Intermediate SSTI
Cellulitis
Subcutaneous abscess
Deep SSTI
Necrotizing fasciitis
Myositis or pyomyositis

6. Characteristics of GAS SSTIs in Children
Deep SSTI
n = 9
Intermediate SSTI
N = 30
Superficial SSTI
n = 23
F : M
5 : 4
14 : 16
8 : 15
Age, mean ± S.D
8.5 ± 4.0
9.1 ± 5.6
7.9 ± 4.3
Days of onset, mean ± S.D
3.8 ± 2.7
5.3 ± 13.7
9.1 ± 14.0
Fever, n (%)
9 (100)
19/29 (65.5)+
4 (17.4)＃
Trauma history, n (%)
2 (22.2)
10 (33.3)
4 (17.3)
Scarlet fever, n (%)
1 (11.1)
5 (16.7)
3 (13.0)
Toxic shock, n (%)
3 (33.0)*
0 (0)
0 (0)＃
Hospitalization rate, n (%)
20 (66.7)+
5 (21.7)＃
Hospitalization days
29.2 ± 30.2*
5.9 ± 2.6
3.8 ± 0.8＃
Antibiotic duration, days
74.1 ± 131.2*
11.5 ± 6.9
8.6 ± 4.3＃
Operation
6 (66.7)*
1 (3.3)
* : Deep versus Intermediate with statistically significance (P < 0.05)
+ : Intermediate versus superficial with statistically significance (P < 0.05)
＃ : Deep versus superficial with statistically significance (P < 0.05)

7. Laboratory Findings of GAS SSTIs in Children
Deep SSTIs
n = 9
Intermediate SSTIs
n = 30
Superficial SSTIs
n = 23
WBC (/mm3)
20078 ± 13625
16542 ± 7141
15400 ± 4047
Platelet (103/μL)
234.9 ± 135.5*
331.1 ± 104.3
273.6 ± 128.7
CRP (mg/L)
201.6 ± 128.1*
50.4 ± 44.2
49.9 ± 27.8＃
ESR (mm/hr)
40.9 ± 12.2
61.6 ± 35.6
30 ± 0
ORSA co-infection, n (%)
0 (0)
4 (13.3)
9 (39.1)＃
Blood culture
5 (55.6)*
1/23 (4.3)
0 (0)＃
Antimicrobial susceptibility
Penicillin
9/9 (100)
29/29 (100)
23 (100)
Cefazolin
8/8 (100)
28/29 (96.6)
Clindamycin
27/29 (93.1)
22 (95.7)
Erythromycin
7/9 (77.8)
22/29 (75.9)
19 (82.6)
Tetracycline
6/9 (66.7)
17/29 (58.6)+
6 (26.1)＃
* : Deep versus Intermediate with statistically significance (P < 0.05)
+ : Intermediate versus superficial with statistically significance (P < 0.05)
＃ : Deep versus superficial with statistically significance (P < 0.05)

9. Microbiologic features of GAS SSTIs in Children
Deep SSTI
n = 9
Intermediate
n = 30
Superficial SSTI
n = 23
Superantigen, n (%)
Spe A
Spe B
Spe C
Spe F
Spe G
Spe H
Spe J
Smez
Ssa
5 (55.6)
9 (100)
4 (44.4)
2 (22.2)
1 (11.1)
10 (33.3)
29 (96.7)
16 (53.3)
28 (93.3)
22 (73.3)
7 (23.3)
9 (30)
15 (50)
4 (17.4)＃
23 (100)
12 (52.2)
17 (73.9)
5 (21.7)
3 (13)＃
11 (47.8)
9 (39.1)
＃ : Deep versus superficial with statistically significance (P < 0.05) 9

10. Conclusion
M1 is the most prevalent type in deep skin and soft tissue infections.
SpeA and SpeJ tend to be present more in deep than in superficial skin and soft tissue infections.
Group A streptococcal SSTI remains a great challenge to clinicians since it may be accompanied with sepsis, toxic shock or even necrotizing fasciitis.
Prevention, prompt diagnosis and etiology identification were important in clinical management.

11. Thank you for your attention !

12. Discussion
Most frequently detected type in invasive isolates was emm1.
M1 was the strongest predictor for invasive infection.
Spea1–spea3 and spej, and smez are present statistically significantly more often in isolates from invasive infections.
Ssa, spec, and spei were more frequent in noninvasive isolates.
J. Inf. Dis. 2010; 202(1):20–28

13. Discussion When comparing NF with other invasive skin and soft tissue
infection, the presence of speC gene was significantly associated
with NF strains (66.7% vs. 21.1%, P ).
The predominant emm types of throat (emm49 and emm75)
samples were different from those of skin (emm44, emm81 and
emm112) samples.
Emm types 1, 3 and 12 were independent risk factors associated
with mortality in 5400 cases of invasive GAS infection
Ped. Inf. Dis
BMC Microbiol Sep 16;8:150
Clin Infect Dis. 2007;45(7):853

14. M1 M1 M1 M1 M1 M4
M22
M82
M57 M1
721
447
668
614
1770
1131 78
1870
1020
720