Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
Pediatr Infect Dis J. 2013 Jan;32(1):72-7. doi: 10.1097/INF.0b013e318270d850.
Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus are commonly carried in the nasopharynx of young children, and have been speculated to interact with each other. Although earlier studies used cultures alone to assess these interactions, the addition of real-time quantitative polymerase chain reaction (qPCR) provides further insight into these interactions. We compared results of culture and qPCR for the detection of these 3 bacteria in 446 nasopharynx samples collected from 360 healthy young children in a prospective cohort study in the Peruvian Andes. Patterns of concurrent bacterial colonization were studied using repeated measures logistic regression models with generalized estimating equations. Spearman correlation coefficients were used to assess correlations among bacterial densities. At a bacterial density <10 colony forming units/mL measured by qPCR, culture detected significantly less carriers (P < 0.0001) for all 3 pathogens, than at a bacterial density >10 colony forming units/mL. In addition, there was a positive association between S. pneumoniae and H. influenzae colonization measured by both culture (odds ratio [OR] 3.11-3.17, P < 0.001) and qPCR (OR 1.95-1.97, P < 0.01). The densities of S. pneumoniae and H. influenzae, measured by qPCR, were positively correlated (correlation coefficient 0.32, P < 0.001). A negative association was found between the presence of S. pneumoniae and Staphylococcus aureus in carriage with both culture (OR 0.45, P = 0.024) and qPCR (OR 0.61, P < 0.05). The impact of density on detection by culture and the observed density-related interactions support use of qPCR in additional studies to examine vaccine effects on diverse bacterial species.
肺炎链球菌、流感嗜血杆菌和金黄色葡萄球菌通常存在于幼儿的鼻咽部，并且被推测相互作用。尽管早期的研究仅使用培养物来评估这些相互作用，但实时定量聚合酶链反应（qPCR）的加入提供了对这些相互作用的进一步了解。我们比较了培养物和 qPCR 对 360 名秘鲁安第斯山区健康幼儿前瞻性队列研究中 446 个鼻咽样本中这 3 种细菌的检测结果。使用广义估计方程的重复测量逻辑回归模型研究了同时细菌定植的模式。使用 Spearman 相关系数评估细菌密度之间的相关性。在 qPCR 测量的细菌密度<10 个菌落形成单位/毫升时，与细菌密度>10 个菌落形成单位/毫升时相比，培养物检测到所有 3 种病原体的携带者显著减少（P<0.0001）。此外，培养物（比值比 [OR] 3.11-3.17，P<0.001）和 qPCR（OR 1.95-1.97，P<0.01）测量的肺炎链球菌和流感嗜血杆菌定植之间存在正关联。qPCR 测量的肺炎链球菌和流感嗜血杆菌的密度呈正相关（相关系数 0.32，P<0.001）。培养物和 qPCR 均发现肺炎链球菌和金黄色葡萄球菌共存存在负相关（OR 0.45，P=0.024；OR 0.61，P<0.05）。密度对培养物检测的影响以及观察到的与密度相关的相互作用支持在其他研究中使用 qPCR 来检查疫苗对多种细菌的影响。
