Department of Life Sciences, Manchester Metropolitan Universitygrid.25627.34, Manchester, United Kingdom.
Department of Natural Sciences, Manchester Metropolitan Universitygrid.25627.34, Manchester, United Kingdom.
Microbiol Spectr. 2022 Oct 26;10(5):e0041922. doi: 10.1128/spectrum.00419-22. Epub 2022 Aug 16.
Microbiological surveillance of airway secretions is central to clinical care in cystic fibrosis (CF). However, the efficacy of microbiological culture, the diagnostic gold standard for pathogen detection, has been increasingly questioned. Here we compared culture with targeted quantitative PCR (QPCR) for longitudinal detection of 2 key pathogens, Pseudomonas aeruginosa and Staphylococcus aureus. Prospectively collected respiratory samples taken from 20 pediatric and 20 adult CF patients over a period of 3-years were analyzed. Patients were eligible if considered free of chronic Pseudomonas infection within 12-months prior to start of study. QPCR revealed high levels of infection with both pathogens not apparent from culture alone. Pseudomonas and Staphylococcus were detected by culture on at least one sampling occasion in 12 and 29 of the patients, respectively. Conversely, both pathogens were detected in all 40 patients by QPCR. Classification of infection status also significantly altered in both pediatric and adult patients, where the number of patients deemed chronically infected with Pseudomonas and Staphylococcus increased from 1 to 28 and 9 to 34, respectively. Overall, Pseudomonas and Staphylococcus infection status classification changed respectively for 36 and 27 of all patients. In no cases did molecular identification lead to a patient being in a less clinically serious infection category. Pathogen detection and infection status classification significantly increased when assessed by QPCR in comparison to culture. This could have implications for clinical care of CF patients, including accuracy of infection diagnosis, relevant and timely antibiotic selection, antimicrobial resistance development, establishment of chronic infection, and cross-infection control. Chronic lung infection is the leading cause of morbidity and early mortality for people with cystic fibrosis (pwCF). Microbiological surveillance to detect lung pathogens is recommended as best practise in CF patient care. Here we studied pathogen detection in 40 pwCF over several years. We found that microbiological culture, the diagnostic gold standard, was significantly disparate to targeted culture-independent approaches for detection and determination of chronic infection status of two important pathogens in CF. Pathogen detection was significantly lower by culture and consequently infection status was also misclassified in most cases. In particular, the extent of chronic infection by both P. aeruginosa and S. aureus not realized with culture was striking. Our findings have implications for the development of infection and clinical care of pwCF. Future longitudinal studies with greater patient numbers will be needed to establish the full extent of the clinical implications indicated from this study.
气道分泌物的微生物监测是囊性纤维化 (CF) 临床护理的核心。然而，微生物培养的疗效，即病原体检测的诊断金标准，越来越受到质疑。在这里，我们比较了培养和靶向定量 PCR（QPCR）在 2 种关键病原体，铜绿假单胞菌和金黄色葡萄球菌的纵向检测中的作用。对 20 名儿科和 20 名成年 CF 患者在 3 年期间采集的前瞻性呼吸样本进行了分析。如果患者在研究开始前 12 个月内被认为没有慢性铜绿假单胞菌感染，则符合入选条件。QPCR 显示，两种病原体的感染水平均高于单独培养时的水平。在 12 名患者中，至少有一次采样时通过培养检测到铜绿假单胞菌和金黄色葡萄球菌，在 29 名患者中，分别通过培养检测到这两种病原体。相反，40 名患者均通过 QPCR 检测到这两种病原体。儿科和成年患者的感染状态分类也发生了显著变化，慢性感染铜绿假单胞菌和金黄色葡萄球菌的患者数量分别从 1 例增加到 28 例和从 9 例增加到 34 例。总体而言，36 名患者的感染状态分类发生了变化，27 名患者的感染状态分类发生了变化。在任何情况下，分子鉴定都不会导致患者的临床感染类别降低。与培养相比，通过 QPCR 进行评估时，病原体检测和感染状态分类显著增加。这可能对 CF 患者的临床护理产生影响，包括感染诊断的准确性、相关和及时的抗生素选择、抗菌药物耐药性的发展、慢性感染的建立以及交叉感染的控制。慢性肺部感染是囊性纤维化（CF）患者发病和早期死亡的主要原因。微生物监测以检测肺部病原体是 CF 患者护理的最佳实践。在这里，我们研究了 40 名 CF 患者在几年中的病原体检测情况。我们发现，微生物培养，即诊断金标准，与针对 CF 中两种重要病原体的靶向非培养方法相比，在检测和确定慢性感染状态方面存在显著差异。通过培养检测到的病原体数量明显较少，因此大多数情况下感染状态也被错误分类。特别是，通过培养无法发现的铜绿假单胞菌和金黄色葡萄球菌的慢性感染程度令人震惊。我们的研究结果对 CF 患者的感染和临床护理的发展有影响。需要进行更多患者的前瞻性纵向研究，以确定从这项研究中得出的临床意义的全部范围。
