2004 - 2005年美国耐抗生素肺炎链球菌的流行病学变化
Changing epidemiology of antimicrobial-resistant Streptococcus pneumoniae in the United States, 2004-2005.
作者信息
Richter Sandra S, Heilmann Kristopher P, Dohrn Cassie L, Riahi Fathollah, Beekmann Susan E, Doern Gary V
机构信息
Department of Pathology, University of Iowa Carver College of Medicine, Iowa City, IA 52242-1009, USA.
出版信息
Clin Infect Dis. 2009 Feb 1;48(3):e23-33. doi: 10.1086/595857.
BACKGROUND
The impact of pediatric 7-valent pneumococcal conjugate vaccination (PCV-7) on the population of Streptococcus pneumoniae in the United States was examined by determining the serotypes, antimicrobial resistance profiles, and genetic relatedness of isolates from patients with invasive and noninvasive infections during the 2004-2005 respiratory illness season.
METHODS
Susceptibility testing, serotyping, and pulsed-field gel electrophoresis analysis were performed on 1647 S. pneumoniae isolates obtained from 41 US medical centers in 2004-2005 as part of a longitudinal antimicrobial resistance surveillance program. The results were compared with surveillance data from earlier periods.
RESULTS
From the 1999-2000 to the 2004-2005 respiratory illness season, the prevalence of isolates with intermediate penicillin resistance (minimum inhibitory concentration, 0.1-1 microg/mL) increased from 12.7% to 17.9%, prevalence of penicillin-resistant isolates (minimum inhibitory concentration, >or=2 microg/mL) decreased from 21.5% to 14.6%, and prevalence of isolates resistant to erythromycin increased from 25.7% to 29.1% among S. pneumoniae isolates. The prevalence of multidrug resistance among isolates did not change (22.4% in 1999-2000 and 20.0% in 2004-2005). Sixty different serotypes were recognized among the isolates from 2004-2005; predominant serotypes were 19A (14.5%), 3 (11.2%), 6A (7.1%), 19F (7%), and 11A (6%). Serotypes that were included in PCV-7 accounted for 16.3% of isolates; 28.4% of strains isolated had PCV-7-related serotypes, and the remaining 55.3% of isolates had serotypes that were unrelated to PCV-7. The serotype distribution of the penicillin-resistant S. pneumoniae population changed from 1999-2000 to 2004-2005, with an increase in the prevalence of serotype 19A (1.5% to 35.4%) and serotype 35B (1.2% to 12.5%) and a decrease in the prevalence of most PCV-7 serotypes, including 23F (16.1% to 5%), 9V (16.1% to 4.2%), 6B (13.7% to 3.8%), and 14 (18.5% to 2.9%).
CONCLUSIONS
The penicillin-resistant S. pneumoniae population has changed; most isolates are now closely related to 2 Pneumococcal Molecular Epidemiology Network clones that increased in prevalence from 1999-2000 to 2004-2005 (Taiwan(19F)-14 [14.6% to 36.7%; 60% were serotype 19A] and Utah(35B)-24 [0.9% to 16.3%]).
背景
通过确定2004 - 2005年呼吸道疾病季节期间侵袭性和非侵袭性感染患者分离株的血清型、抗菌药物耐药谱及基因相关性，研究了7价肺炎球菌结合疫苗（PCV - 7）对美国肺炎链球菌种群的影响。
方法
作为一项纵向抗菌药物耐药监测项目的一部分，对2004 - 2005年从美国41个医疗中心获得的1647株肺炎链球菌分离株进行了药敏试验、血清分型和脉冲场凝胶电泳分析。将结果与早期的监测数据进行比较。
结果
从1999 - 2000年到2004 - 2005年呼吸道疾病季节，肺炎链球菌分离株中青霉素中介耐药（最低抑菌浓度，0.1 - 1μg/mL）的患病率从12.7%增至17.9%，青霉素耐药分离株（最低抑菌浓度，≥2μg/mL）的患病率从21.5%降至14.6%，对红霉素耐药的分离株患病率从25.7%增至29.1%。分离株中的多重耐药患病率未发生变化（1999 - 2000年为22.4%，2004 - 2005年为20.0%）。在2004 - 2005年的分离株中识别出60种不同血清型；主要血清型为19A（14.5%）、3（11.2%）、6A（7.1%）、19F（7%）和11A（6%）。PCV - 7中包含的血清型占分离株的16.3%；分离出的菌株中有28.4%具有与PCV - 7相关的血清型，其余55.3%的分离株具有与PCV - 7不相关的血清型。1999 - 2000年至2004 - 2005年，青霉素耐药肺炎链球菌种群的血清型分布发生了变化，19A（1.5%至35.4%）和35B（1.2%至12.5%）的患病率增加，而包括23F（16.1%至5%）、9V（16.1%至4.2%）、6B（13.7%至3.8%）和14（18.5%至2.9%）在内的大多数PCV - 7血清型的患病率下降。
结论
青霉素耐药肺炎链球菌种群已发生变化；目前大多数分离株与2个肺炎球菌分子流行病学网络克隆密切相关，这2个克隆在1999 - 2000年至2004 - 2005年期间患病率增加（台湾（19F） - 14 [14.6%至36.7%；60%为19A血清型]和犹他（35B） - 24 [0.9%至16.3%]）。
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