Genetic diversity and evolutionary relationships among Legionella pneumophila clinical isolates, Portugal, 1987 to 2012

Abstract

The genetic diversity of 89 clinical Legionella isolates, collected between 1987 and 2012, in 22 hospitals from the five regions of Portugal, was analysed in this study using monoclonal antibodies (MAbs) of the Dresden panel and the sequence-based typing (SBT) protocol. The eBURST algorithm was used to infer levels of relatedness between isolates. All isolates collected were Legionella pneumophila, which were further characterised into four subgroups by MAbs, and 30 sequence types (STs) by SBT. Twelve of the STs were unique to Portugal; one of them (ST100) was represented by 32 epidemiologically related isolates. The ST44 was the profile with the highest number of epidemiologically unrelated isolates. The eBURST analyses indicate that, within the group formed by the 30 STs identified in this study, 17 STs were genetically close to at least another ST in the group. The comparison between the eBURST diagrams obtained with the STs from this study and the entire SBT database of the European Working Group for Legionella, showed that 24 (seven of them unique to Portugal) of our 30 STs were related with STs identified in others countries. These results suggest that the population of L. pneumophila clinical strains in Portugal includes both worldwide and local strains.

Legionella pneumophila and Other Legionella Species Isolated from Legionellosis Patients in Japan between 2008 and 2016

“…Among the 419 L. pneumophila isolates, 187 STs (including 126 singletons) were detected ( Table 3) (18). The IOD for the 419 clinical isolates (IOD of 0.984) was similar that that obtained by analyzing the 86 clinical isolates in our previous study (IOD of 0.979) (15) and was similar to the value obtained in a study conducted in Portugal (IOD of 0.972) (19). In the case of SG1 only, 372 isolates were divided into 159 STs, with the IOD being 0.980, which was similar to the finding for all SGs included and was greater than the IOD of 0.924 obtained in a study of sporadic cases conducted in the United States (20) and the IOD of 0.879 obtained in a study conducted in Belgium (21) .…”

A large community outbreak of Legionnaires’ disease in Vila Franca de Xira, Portugal, October to November 2014

“…In the largest outbreak with 449 confirmed cases in Murcia, Spain, in 2001, a microbiological link between cases and a hospital cooling tower was demonstrated in the months after the outbreak [5]. Timely collection of respiratory secretion specimens by hospitals and widespread environmental sampling in the early phase of the outbreak allowed identification of a microbiological link between the environment samples and patient isolates [6].…”

Characterization of Legionella pneumophila Populations by Multilocus Variable Number of Tandem Repeats (MLVA) Genotyping from Drinking Water and Biofilm in Hospitals from Different Regions of the West Bank

“…In a study conducted across the United States, ST1 was the most frequent sequence type between both clinical sporadic and environmental isolates, accounting for 25% and 49% of the total number of isolates, respectively [68]. In Europe, ST1 has also been reported as the most predominant sequence type among environmental isolates in Germany [71], England and Wales [60], Portugal [72], Spain [73], France [74] and Italy [75].…”