First Department of Internal Medicine, Division of Respiratory Medicine, Infectious Disease and Allergology, Kansai Medical University, Japan.
National Hospital Organization Okinawa National Hospital, Japan.
J Infect Chemother. 2022 Oct;28(10):1353-1357. doi: 10.1016/j.jiac.2022.06.012. Epub 2022 Jul 8.
Legionella pneumophila is a major causative pathogen of community-acquired pneumonia (CAP), but recently the novel coronavirus disease 2019 (COVID-19) became the most common causative pathogen of CAP. Because L. pneumophila CAP is clinically distinct from bacterial CAPs, the Japan Society for Chemotherapy (JSC) developed a simple scoring system, the Legionella Score, using six parameters for the presumptive diagnosis of L. pneumophila pneumonia. We investigated the clinical and laboratory differences of L. pneumophila CAP and COVID-19 CAP and validated the Legionella Score in both CAP groups. We analyzed 102 patients with L. pneumophila CAP and 956 patients with COVID-19 CAP. Dyspnea and psychiatric symptoms were more frequently observed and cough was less frequently observed in patients with L. pneumophila CAP than those with COVID-19 CAP. Loss of taste and anosmia were observed in patients with COVID-19 CAP but not observed in those with L. pneumophila CAP. C-reactive protein and lactate dehydrogenase levels in L. pneumophila CAP group were significantly higher than in the COVID-19 CAP group. In contrast, sodium level in the L. pneumophila CAP group was significantly lower than in the COVID-19 CAP group. The median Legionella Score was significantly higher in the L. pneumophila CAP group than the COVID-19 CAP group (score 4 vs 2, p < 0.001). Our results demonstrated that the JSC Legionella Score had good diagnostic ability during the COVID-19 pandemic. However, physicians should consider COVID-19 CAP when loss of taste and/or anosmia are observed regardless of the Legionella Score.
嗜肺军团菌是社区获得性肺炎（CAP）的主要病原体，但最近新型冠状病毒病 2019（COVID-19）成为 CAP 的最常见病原体。由于嗜肺军团菌 CAP 在临床上与细菌性 CAP 不同，日本化疗学会（JSC）使用六个参数开发了一种简单的评分系统，即军团菌评分，用于推定诊断肺炎嗜肺军团菌。我们研究了嗜肺军团菌 CAP 和 COVID-19 CAP 的临床和实验室差异，并在两个 CAP 组中验证了军团菌评分。我们分析了 102 例嗜肺军团菌 CAP 患者和 956 例 COVID-19 CAP 患者。与 COVID-19 CAP 患者相比，嗜肺军团菌 CAP 患者更常出现呼吸困难和精神症状，而咳嗽较少。味觉和嗅觉丧失见于 COVID-19 CAP 患者，但未见于嗜肺军团菌 CAP 患者。嗜肺军团菌 CAP 组的 C 反应蛋白和乳酸脱氢酶水平明显高于 COVID-19 CAP 组。相反，嗜肺军团菌 CAP 组的钠水平明显低于 COVID-19 CAP 组。嗜肺军团菌 CAP 组的中位军团菌评分明显高于 COVID-19 CAP 组（评分 4 比 2，p<0.001）。我们的研究结果表明，在 COVID-19 大流行期间，JSC 军团菌评分具有良好的诊断能力。然而，无论军团菌评分如何，当出现味觉和/或嗅觉丧失时，医生都应考虑 COVID-19 CAP。
