Reemergence of emm1 and a changed superantigen profile for group a streptococci causing invasive infections:: Results from a nationwide study
Reemergence of emm1 and a changed superantigen profile for group a streptococci causing invasive infections:: Results from a nationwide study
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DOI：
10.1128/jcm.43.4.1789-1796.2005
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发表时间：
2005-04-01
影响因子：
9.4
通讯作者：
Konradsen, HB
中科院分区：
文献类型：
--
作者：
Ekelund, K;Skinhoj, P;Konradsen, HB
1999年至2002年间，作为国家监测的一部分，从丹麦临床微生物科收到了496株侵袭性A群链球菌（GAS）分离株，随后从治疗患者的临床医生那里收到了487份（98%）问卷。检测emm型及链球菌超抗原（SAg）基因。侵袭性GAS感染的发生率平均为每年2.3 / 10万。无局灶性症状的菌血症（27%）与丹毒（20%）是最常见的临床诊断。10%的患者发生链球菌中毒性休克综合征，其中56%死亡。30天内的总病死率为23%。共鉴定出47种不同的emm类型，其中emm1、emm3、emm4、emm12、emm28和emm89在493株现有分离株中占72%。在4年期间，emm1的存在从1999年的16%增加到2002年的40%。同时，emm3的存在从1999年的23%下降到2002年的2%。emm1分离株主要携带speA，但频率从1999年的94%下降到2002年的71%，而emm1特异性speC的流行率从25%上升到53%。从历史的角度来看，这可以解释为emm1的再次出现，并可能表明可能引入新的emm1亚克隆。然而，在研究期间，这种复发并没有导致临床表现的任何显著变化。我们的研究结果显示了侵袭性GAS感染的复杂性，emm和SAg基因的发病率和分布随时间的变化而变化，这强调了持续流行病学和分子研究的必要性。
Between 1999 and 2002, 496 invasive group A streptococcal (GAS) isolates from clinical microbiological departments in Denmark and subsequently 487 (98%) questionnaires from the clinicians treating the patients were received as part of a national surveillance. emm types and streptococcal superantigen (SAg) genes were determined. The incidence of invasive GAS infections was on average 2.3 per 100,000 per year. Bacteremia with no focal symptoms (27%) was together with erysipelas (20%) the most prevalent clinical diagnoses. Streptococcal toxic shock syndrome occurred in 10% of patients, of which 56% died. The overall case fatality rate within 30 days was 23%. In total, 47 different emm types were identified, of which emm1, emm3, emm4, emm12, emm28, and emm89 were identified in 72% of the 493 available isolates. During the 4-year period the presence of emm1 increased from 16% in 1999 to 40% in 2002. Concurrently, the presence of emm3 decreased from 23% in 1999 to 2% in 2002. The emm1 isolates predominantly carried speA, although the frequency decreased from 94% in 1999 to 71% in 2002, whereas the emm1-specific prevalence of speC increased from 25 to 53%. In a historical perspective, this could be interpreted as a reemergence of emm1 and could indicate a possible introduction of a new emm1 subclone. However, this reemergence did not result in any significant changes in the clinical manifestations during the study period. Our results show the complexity of invasive GAS infections, with time-dependent variations in the incidence and distribution of emm and SAg genes, which emphasizes the need for continuous epidemiological and molecular investigations.