ABSTRACTThe aim of this study is to explore the dispersion, clonality, and virulence ofLegionella pneumophilaserogroups 2 to 14 in the Greek environment. EightyL. pneumophilaserogroup 2 to 14 strains isolated from water distribution systems of hotels, hospitals, athletic venues, and ferries in Greece were tested by monoclonal antibodies (MAbs) for serogroup discrimination and molecularly by amplified fragment length polymorphism (AFLP) for genetic diversity. Fifty-six of 80 strains were also typed by the sequence-based typing (SBT) method. Αll strains were further analyzed for detection of two pathogenicity loci:Legionellavirhomologue (lvh) and repeats in structural toxin (rtxA). Thirty-seven strains (46.2%) belonged to serogroup 6, 26 strains (32.5%) to serogroup 3, and 7 (8.8%) to other serogroups (4, 5, 8, and 10). Ten strains (12.5%) were nontypeable (NT) into the known serogroups. Thirty-nine different AFLP types were found among the 80L. pneumophilaserogroup 2 to 14 strains, and 24 different SBT types were found among the 56 strains tested. Among the 80 strains, thelvhlocus was present in 75 (93.8%), thertxAlocus was found in 76 (95%), and both loci were found in 73 (91.3%) strains. This study showed that there is genetic variability ofL. pneumophilaserogroups 2 to 14 in the Greek environment as well as a high percentage of the pathogenicity loci. Ιntroducing an effective diagnostic test forL. pneumophilaserogroups 2 to 14 in urine and promoting the examination of respiratory specimens from patients hospitalized for pneumonia in Greek hospitals are essential.IMPORTANCEIn this study, the dispersion, clonality, and virulence of environmental isolates ofLegionella pneumophilaserogroups 2 to 14 (Lp2–14) in Greece were investigated. Genetic variability of Lp2–14 in the Greek environment was identified together with the presence of the pathogenicity loci in a high percentage of the isolates. Despite the high prevalence of Lp2–14 in the Greek environment, no clinical cases were reported, which may be due to underdiagnosis of the disease. Almost all the legionellosis cases are diagnosed in Greece by using the urine antigen test, which is specific for Lp1. There is an urgent need to improve the clinical diagnosis of legionellosis by introducing an effective diagnostic test for Lp2–14 in urine and by promoting the PCR examination of respiratory specimens from patients with compatible clinical symptoms.
A Predominant and Virulent Legionella pneumophila Serogroup 1 Strain Detected in Isolates from Patients and Water in Queensland, Australia, by an Amplified Fragment Length Polymorphism Protocol and Virulence Gene-Based PCR Assays
