社区获得性肺炎中军团菌感染的血清学诊断。

Sero diagnosis of Legionella infection in community acquired pneumonia.

机构信息

Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India.

出版信息

Indian J Med Res. 2010 Jan;131:92-6.

PMID:20167980

Abstract

BACKGROUND & OBJECTIVES: Legionella pneumophila has been increasingly recognized as an emerging pathogen responsible for community acquired pneumonia (CAP) worldwide. In India, the actual burden is not known. The present study was thus undertaken to see the presence of Legionella infection in patients with community acquired pneumonia admitted in a tertiary care centre in north India.

METHODS

Both children and adults (n=113) with symptoms of pneumonia were included in the study. Clinical samples (blood, urine, nasopharyngeal aspirates, bronchoalveolar lavage, sputum, etc.) were collected and subjected to culture and other tests. Enzyme linked immunosorbent assay (ELISA) was done by commercial kits for all the three classes of immunoglobulins (IgG, IgM & IgA). Urinary antigen was also detected using commercial kits. Culture was performed on 51 respiratory tract fluid samples. Serum samples of 44 healthy controls were also screened for the presence of anti-legionella antibodies (IgG, IgM & IgA).

RESULTS

Thirty one of the 113 cases (27.43%) were serologically positive. Anti-legionella IgG, IgM and IgA antibodies were positive in 7.96, 15.92 and 11.50 per cent patients respectively. In controls, seropositivity was 9.09 (4/44). IgA was positive in 3 and IgM, IgG combined in one. Antigenuria detection by Microwell ELISA kit showed 17.69 per cent positivity. Four antigenuria positive patients were also serologically positive; of these two patients were positive for IgM, hence considered as confirmed cases of Legionella infection. None of the sample was culture positive.

INTERPRETATION & CONCLUSIONS: Combination of serology and antigenuria detection may be a valuable tool for the diagnosis of Legionella infection in absence of culture positivity. In order to evaluate the actual burden of Legionella in community acquired pneumonia, further studies with larger samples need to be done.

摘要

背景与目的

嗜肺军团菌已被越来越多地认为是一种新兴的病原体，可导致全球社区获得性肺炎（CAP）。在印度，实际负担尚不清楚。因此，本研究旨在观察印度北部一家三级保健中心收治的社区获得性肺炎患者中军团菌感染的存在情况。

方法

本研究纳入了有肺炎症状的儿童和成人（n=113）。采集临床标本（血液、尿液、鼻咽抽吸物、支气管肺泡灌洗、痰等）并进行培养和其他检测。使用商业试剂盒进行酶联免疫吸附试验（ELISA），检测所有三类免疫球蛋白（IgG、IgM 和 IgA）。使用商业试剂盒检测尿抗原。对 51 份呼吸道液样本进行培养。还对 44 名健康对照者的血清样本进行了抗军团菌抗体（IgG、IgM 和 IgA）筛查。

结果

113 例患者中 31 例（27.43%）血清学阳性。抗军团菌 IgG、IgM 和 IgA 抗体阳性率分别为 7.96%、15.92%和 11.50%。在对照组中，血清阳性率为 9.09%（4/44）。IgA 阳性 3 例，IgM 和 IgG 联合阳性 1 例。微孔酶联免疫吸附试验试剂盒检测尿抗原显示阳性率为 17.69%。4 例尿抗原阳性患者血清学也呈阳性；其中 2 例患者 IgM 阳性，故被认为是军团菌感染的确诊病例。无样本培养阳性。