Lonks John R.
Miriam Hospital, 164 Summit Avenue, Providence, RI 02906, USA.
Curr Infect Dis Rep. 2004 Feb;6(1):7-12. doi: 10.1007/s11908-004-0018-1.
Respiratory tract infections are treated empirically. Treatment is based on the likely pathogens and their antibiotic susceptibility. The most common respiratory tract pathogen is Streptococcus pneumoniae. In the United States, approximately 25% to 30% of S. pneumoniae are resistant to erythromycin and other macrolides. There are two mechanisms of resistance: ribosomal methylation that causes high-level resistance, and an efflux pump that causes low-level resistance. Macrolides are ineffective in animal models that use pneumococcal isolates with the methylase- or efflux-mediated resistance mechanisms. There are many case reports that describe clinical failure and isolation of a macrolide-resistant pneumococcus while a patient receives macrolide treatment. Two recent studies that included macrolide-susceptible and macrolide-resistant pneumococci showed that breakthrough bacteremia in patients receiving macrolide treatment occurred only with macrolide-resistant isolates. Study of bacteremic disease ensures the pathogenic role of the pneumococcus; however, it underestimates the true clinical impact of macrolide resistance.
呼吸道感染通常采用经验性治疗。治疗方案基于可能的病原体及其抗生素敏感性。最常见的呼吸道病原体是肺炎链球菌。在美国，约25%至30%的肺炎链球菌对红霉素和其他大环内酯类抗生素耐药。耐药机制有两种：导致高水平耐药的核糖体甲基化，以及导致低水平耐药的外排泵。在使用具有甲基化或外排介导耐药机制的肺炎球菌分离株的动物模型中，大环内酯类抗生素无效。有许多病例报告描述了患者接受大环内酯类治疗时出现临床治疗失败以及分离出耐大环内酯类肺炎球菌的情况。最近两项纳入了对大环内酯类敏感和耐药肺炎球菌的研究表明，接受大环内酯类治疗的患者出现突破性菌血症仅与耐大环内酯类分离株有关。对菌血症性疾病的研究确定了肺炎球菌的致病作用；然而，它低估了大环内酯类耐药的真正临床影响。
