Laboratory diagnosis of legionnaires’ disease due to Legionella pneumophila serogroup 1: comparison of phenotypic and genotypic methods

• DOI: 10.1099/jmm.0.05464-0
• Publication Date: 2004-02-17T23:19:03Z
• Authors: Diane S.J. Lindsay; William H. Abraham; William Findlay; Peter Christie; Fiona Johnston; Giles F.S. Edwards
• Keywords: Legionella; Legionnaires' disease

Laboratory results of 67 cases legionnaires' disease caused by Legionella pneumophila serogroup (Sg) 1 spanning a 6-year period were analysed both phenotypic and genotypic methods. The methods compared urinary antigen enzyme immunoassay (EIA), an immunofluorescent antibody (IFA) test, direct fluorescent (DFA), culture 5S rRNA PCR with Southern blotting confirmation. Urine was available in 53 cases, which 35 (66%) positive, peak observed at 5-10 days after onset symptoms. IFA test positive 62 (92.5%) 56 (90.3%) producing greater than fourfold rise titre 6 (9.7%) giving presumptive high titres > or =1:128. There two peaks, one 10-15 another >25 onset. In 23 where samples available, DFA respectively 5 (22%) 10 (48%) cases. culture-positives disease. A Legionella-specific on patient serum 54 (80.5%) positivity 6-10 22 the full panel diagnostic for comparison. relative sensitivity specificity EIA 100%. gave values 93.8 95%. culture, although 100% specific, produced only low sensitivities, 19 42.8%, respectively. This study has shown that are valuable tests acute phase disease, excellent values. At present, species causing infection requires to be verified serology and/or but this could become unnecessary as new L. Sg 1-specific available.