Comparison of tracheal aspirate and bronchoalveolar lavage samples in the microbiological diagnosis of lower respiratory tract infection in pediatric patients.
Comparison of tracheal aspirate and bronchoalveolar lavage samples in the microbiological diagnosis of lower respiratory tract infection in pediatric patients.
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DOI：
10.1002/ppul.26049
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发表时间：
2022-10
影响因子：
3.1
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中科院分区：
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气管抽吸物（TA）和支气管肺泡灌洗（BAL）标本的细菌培养物可用于评估人工气道患者的下呼吸道感染（LRTI）。TA收集在资源有限或危重疾病的情况下可能是有利的。在儿科人群中比较这些诊断方式的文献很少。对52例接受人工气道LRTI评价的儿科患者进行单中心回顾性分析。所有患者均采集TA标本进行半定量革兰氏染色和培养，然后在48小时内进行BAL。LRTI的微生物学诊断定义为BAL样品具有>25%的中性粒细胞和>104 CFU/ml的一种或多种细菌物种的生长。将TA的检测特征与作为参比标准品的这些BAL结果进行比较。还评估了微生物鉴定的一致性。总体而言，24例患者（47%）符合使用BAL作为诊断标准的LRTI标准。与BAL相比，分离微生物阳性的TA样本对急性LRTI的敏感性较差，无论革兰氏染色半定量白色血细胞（WBC）计数如何。使用微生物生长和至少“中等”WBC的TA诊断阈值产生93%的特异性。当通过TA鉴定微生物时，阳性预测值最高。通过半定量分析，对于无WBC的TA样品，有或无生物体生长的阴性预测值>70%。所有患者培养菌种的完全一致性为58%，在气管内插管患者中观察到更高的一致性。TA获得的培养物在诊断急性LRTI中的作用仍然有限，这一点在我们的队列中与BAL结果的相关性较差。在患者人群和气道类型中诊断LRTI的最佳策略仍然难以捉摸。
Bacterial cultures from tracheal aspirates (TA) and bronchoalveolar lavage (BAL) specimens can be used to assess patients with artificial airways for lower respiratory tract infections (LRTI). TA collection may be advantageous in situations of limited resources or critical illness. Literature comparing these diagnostic modalities in pediatric populations is scarce. Single center, retrospective analysis of 52 pediatric patients with an artificial airway undergoing evaluation for LRTI. All patients had a TA specimen collected for semi-quantitative Gram stain and culture followed by BAL within 48 hours. Microbiologic diagnosis of LRTI was defined as a BAL sample with >25% neutrophils and growth of >104 CFU/ml of one or more bacterial species. The test characteristics of TA were compared to these BAL results as the reference standard. Concordance in micro-organism identification was also assessed. Overall, 24 patients (47%) met criteria for LRTI using BAL as the diagnostic standard. TA samples positive for an isolated organism had poor sensitivity for acute LRTI when compared to BAL, regardless of semi-quantitative white blood cell (WBC) count by Gram stain. Using a TA diagnostic threshold of organism growth and at least “moderate” WBC yielded a specificity of 93%. Positive predictive value was highest when an organism was identified by TA. Negative predictive value was >70% for TA samples with no WBC by semi-quantitative analysis, with or without growth of an organism. Complete concordance of cultured species was 58% for all patients, with a higher rate seen among those with endotracheal tubes. The role of cultures obtained by TA remains limited for the diagnosis of acute LRTI as demonstrated by the poor correlation to BAL results within our cohort. Optimal strategies for diagnosing LRTI across patient populations and airway types remain elusive.