Dagan R
Pediatric Infectious Disease Unit, Soroka University Medical Center, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
Clin Microbiol Infect. 2009 Apr;15 Suppl 3:16-20. doi: 10.1111/j.1469-0691.2009.02726.x.
Studies have shown that vaccination with seven-valent pneumococcal conjugate vaccine (PCV7) results in a decline in nasopharyngeal carriage of penicillin-resistant Streptococcus pneumoniae, in carriage of vaccine-type pneumococci, and in replacement by non-vaccine serotypes. Vaccines can reduce pneumococcal resistance in vaccinated and unvaccinated populations by reducing the carriage of antibiotic-resistant serotypes, which protects the vaccinated population and prevents spread of disease to others, and by decreasing antibiotic resistance through overall reduction in antibiotic use. However, while reducing the level of vaccine serotypes and drug-resistant serotypes in the nasopharynx, PCV7 also causes non-vaccine pneumococci replacement. The impact of serotype replacement on disease is not clearly understood. Pelton et al. surveyed two communities shortly after the introduction of the PCV7 immunization programme and found that while colonization with vaccine serotypes declined from 22% to 2% from 2000 to 2003, prevalence of non-vaccine serotypes increased from 7% to 16%. Although penicillin-resistant colonizing S. pneumoniae isolates initially declined, penicillin-intermediate isolates increased 2 years following PCV7 introduction. The change was primarily accounted for by an increase in penicillin-intermediate serotype 19A. Serotype 19A is the only serotype not affected by PCV7 that is prevalent worldwide, clinically important, and highly multidrug-resistant. A study by Hicks et al. established serotype 19A as the predominant post-PCV7 cause of invasive pneumococcal disease (IPD) in children and the elderly. An increase in IPD rates caused by antibiotic-resistant serotype 19A isolates can also occur without vaccination; reports indicate increases in regions characterized by extensive antibiotic use, underscoring the importance of strategies to contain antibiotic resistance.
研究表明，接种七价肺炎球菌结合疫苗（PCV7）可使耐青霉素肺炎链球菌的鼻咽部携带率下降，疫苗型肺炎球菌的携带率下降，并导致被非疫苗血清型取代。疫苗可通过减少抗生素耐药血清型的携带，在接种疫苗和未接种疫苗的人群中降低肺炎球菌耐药性，这既能保护接种疫苗的人群，又能防止疾病传播给他人，还能通过总体减少抗生素使用来降低抗生素耐药性。然而，在降低鼻咽部疫苗血清型和耐药血清型水平的同时，PCV7也会导致非疫苗肺炎球菌的取代。血清型取代对疾病的影响尚不清楚。佩尔顿等人在PCV7免疫规划实施后不久对两个社区进行了调查，发现从2000年到2003年，疫苗血清型的定植率从22%降至2%，而非疫苗血清型的患病率从7%增至16%。虽然最初耐青霉素的肺炎链球菌定植菌株有所下降，但在引入PCV7两年后，青霉素中介菌株增加。这一变化主要是由青霉素中介血清型19A的增加所致。血清型19A是唯一不受PCV7影响、在全球流行、具有临床重要性且高度耐多药的血清型。希克斯等人的一项研究确定血清型19A是儿童和老年人中PCV7接种后侵袭性肺炎球菌疾病（IPD）的主要病因。即使未接种疫苗，由耐抗生素血清型19A菌株引起的IPD发病率也可能增加；报告显示，在抗生素广泛使用的地区发病率有所上升，这凸显了控制抗生素耐药性策略的重要性。
