Harris Aaron M, Bramley Anna M, Jain Seema, Arnold Sandra R, Ampofo Krow, Self Wesley H, Williams Derek J, Anderson Evan J, Grijalva Carlos G, McCullers Jonathan A, Pavia Andrew T, Wunderink Richard G, Edwards Kathryn M, Winchell Jonas M, Hicks Lauri A
Centers for Disease Control and Prevention, Atlanta, Georgia.
Le Bonheur Children's Hospital, Memphis, Tennessee.
Open Forum Infect Dis. 2017 Feb 10;4(1):ofx014. doi: 10.1093/ofid/ofx014. eCollection 2017 Winter.
Specimens collected after antibiotic exposure may reduce culture-based bacterial detections. The impact on culture-independent diagnostic tests is unclear. We assessed the effect of antibiotic exposure on both of these test results among patients hospitalized with community-acquired pneumonia (CAP).
Culture-based bacterial testing included blood cultures and high-quality sputum or endotracheal tube (ET) aspirates; culture-independent testing included urinary antigen testing (adults) for and and polymerase chain reaction (PCR) on nasopharyngeal and oropharyngeal (NP/OP) swabs for and . The proportion of bacterial detections was compared between specimens collected before and after either any antibiotic exposure (prehospital and/or inpatient) or only prehospital antibiotics and increasing time after initiation of inpatient antibiotics.
Of 4678 CAP patients, 4383 (94%) received antibiotics: 3712 (85%) only inpatient, 642 (15%) both inpatient and prehospital, and 29 (<1%) only prehospital. There were more bacterial detections in specimens collected before antibiotics for blood cultures (5.2% vs 2.6%; < .01) and sputum/ET cultures (50.0% vs 26.8%; < .01) but not urine antigen (7.0% vs 5.7%; = .53) or NP/OP PCR (6.7% vs 5.4%; = .31). For all diagnostic testing, bacterial detections declined with increasing time between inpatient antibiotic administration and specimen collection.
Bacteria were less frequently detected in culture-based tests collected after antibiotics and in culture-independent tests that had longer intervals between antibiotic exposure and specimen collection. Bacterial yield could improve if specimens were collected promptly, preferably before antibiotics, providing data for improved antibiotic selection.
抗生素使用后采集的样本可能会减少基于培养的细菌检测。对非培养诊断测试的影响尚不清楚。我们评估了抗生素使用对社区获得性肺炎（CAP）住院患者这两种测试结果的影响。
基于培养的细菌检测包括血培养和高质量痰标本或气管内导管（ET）吸出物；非培养检测包括成人的尿抗原检测（针对 和 ）以及对鼻咽和口咽（NP/OP）拭子进行的聚合酶链反应（PCR）检测（针对 和 ）。比较了在任何抗生素使用（院前和/或住院期间）之前和之后或仅院前使用抗生素后采集的样本以及住院抗生素开始使用后时间延长时细菌检测的比例。
在4678例CAP患者中，4383例（94%）接受了抗生素治疗：3712例（85%）仅在住院期间使用，642例（15%）在住院和院前均使用，29例（<1%）仅在院前使用。抗生素使用前采集的血培养样本（5.2%对2.6%； <.01）和痰/ET培养样本（50.0%对26.8%； <.01）中细菌检测更多，但尿抗原检测（7.0%对5.7%； =.53）或NP/OP PCR检测（6.7%对5.4%； =.31）并非如此。对于所有诊断测试，细菌检测随着住院抗生素给药与样本采集之间时间的增加而下降。
在抗生素使用后采集的基于培养的测试以及抗生素暴露与样本采集间隔时间较长的非培养测试中，细菌检测频率较低。如果能及时采集样本，最好在使用抗生素之前采集，细菌检出率可能会提高，从而为改进抗生素选择提供数据。
