Pfaller M A, Jones R N, Marshall S A, Edmond M B, Wenzel R P
Department of Pathology, University of Iowa College of Medicine, Iowa City 52242, USA.
Diagn Microbiol Infect Dis. 1997 Dec;29(4):259-63. doi: 10.1016/s0732-8893(97)00159-4.
Nosocomial blood stream infections due to streptococci represent an increasingly important problem, particularly among neutropenic cancer patients. This problem is compounded by the emerging resistance to antimicrobial agents commonly used for empiric or prophylactic treatment of hospitalized patients. In this study, we examined the species distribution and antimicrobial susceptibility profile of 295 streptococcal nosocomial blood stream isolates from more than 30 U.S. medical centers (SCOPE National Surveillance Program). Streptococci accounted for 5.9% of all nosocomial blood stream isolates reported. The viridans group streptococci (VGS) were the most frequently isolated streptococci (50.8%), followed by the beta-haemolytic streptococci (31.9%) and pneumococci (13.2%). The beta-haemolytic streptococci were dominated by serogroup B strains (63%), followed by serogroups A and G. Of these organisms, 193 strains were referred for subsequent monitor susceptibility testing. Approximately 14% of S. pneumoniae, 9.2% of VGS, and 0% of beta-haemolytic streptococci were resistant to penicillin. Ceftriaxone was highly active against virtually all isolates (93-100% susceptible) except the VGS (77% susceptible). The rank order for activity of the four agents tested against the 193 isolates was vancomycin > ceftriaxone > penicillin > erythromycin. Importantly, 69% of the penicillin intermediate and resistant strains of VGS were also resistant to at least one additional antimicrobial (31% resistant to ceftriaxone, 51% resistant to erythromycin, 15% resistant to both ceftriaxone and erythromycin). The relatively poor activity of erythromycin against virtually all streptococci and the frequent association of macrolide resistance with penicillin resistance among the VGS suggests that both macrolides and beta-lactam agents might have limited value as prophylactic agents for dental procedures and in empiric or prophylactic use in neutropenic patients.
由链球菌引起的医院血流感染是一个日益重要的问题，尤其在中性粒细胞减少的癌症患者中。住院患者经验性或预防性治疗常用抗菌药物出现的耐药性使这一问题更加复杂。在本研究中，我们检查了来自美国30多个医疗中心的295株医院血流链球菌分离株的菌种分布和抗菌药物敏感性概况（SCOPE国家监测项目）。链球菌占所有报告的医院血流分离株的5.9%。草绿色链球菌（VGS）是最常分离出的链球菌（50.8%），其次是β溶血性链球菌（31.9%）和肺炎链球菌（13.2%）。β溶血性链球菌以B血清群菌株为主（63%），其次是A和G血清群。这些菌株中，193株被送去进行后续的监测药敏试验。约14%的肺炎链球菌、9.2%的VGS和0%的β溶血性链球菌对青霉素耐药。除VGS外（77%敏感），头孢曲松对几乎所有分离株都具有高活性（93 - 100%敏感）。针对193株分离株测试的四种药物的活性排序为万古霉素>头孢曲松>青霉素>红霉素。重要的是，69%的VGS青霉素中介和耐药菌株也对至少一种其他抗菌药物耐药（31%对头孢曲松耐药，51%对红霉素耐药，15%对头孢曲松和红霉素都耐药）。红霉素对几乎所有链球菌的活性相对较差，且VGS中大环内酯类耐药与青霉素耐药频繁相关，这表明大环内酯类和β内酰胺类药物作为牙科手术预防性用药以及中性粒细胞减少患者经验性或预防性用药的价值可能有限。
