AUTHOR=Sreenath K. , Chaudhry Rama , Vinayaraj E. V. , Dey A. B. , Kabra S. K. , Thakur Bhaskar , Guleria Randeep 

TITLE=Distribution of Virulence Genes and Sequence-Based Types Among Legionella pneumophila Isolated From the Water Systems of a Tertiary Care Hospital in India

JOURNAL=Frontiers in Public Health

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2020.596463

DOI=10.3389/fpubh.2020.596463

ISSN=2296-2565

ABSTRACT=<p><bold>Background:</bold> Legionnaires' disease (LD) is a potentially fatal pneumonia predominantly caused by infection due to <italic>Legionella pneumophila</italic> although more than 50 other <italic>Legionella</italic> species are described. Water systems contaminated with <italic>Legionella</italic> spp. are the implicated sources of Legionnaires' disease. In this study, we aimed to assess <italic>Legionella</italic> contamination in the water sources of a tertiary care hospital and to determine the virulence properties and molecular characteristics of <italic>L. pneumophila</italic> environmental isolates.</p><p><bold>Methods:</bold> During May 2015 through August 2018, a total of 201 hospital water samples were tested for <italic>L. pneumophila</italic> by standardized culture procedures; environmental isolates were examined for the presence of two virulence genes: <italic>Legionella vir homolog (lvh)</italic> and <italic>repeats in structural toxin (rtxA)</italic> by PCR. The genotyping of isolates was performed by sequence-based typing (SBT) according to the protocol of the European Study Group for <italic>Legionella</italic> Infections (ESGLI).</p><p><bold>Results:</bold><italic>L. pneumophila</italic> was isolated from 38/201 (18.9%) water samples; among the 46 isolates, the <italic>lvh</italic> locus was present in 45 (97.8%), the <italic>rtxA</italic> locus was found in 45 (97.8%), and both loci were found in 44 (95.7%) isolates. A total of 23 sequence types (STs) were identified among the 44 isolates (index of discrimination [IOD] of 0.929), and 11/23 (47.8%) STs were new to the ESGLI database.</p><p><bold>Conclusions:</bold> The study results showed genetic diversity in <italic>L. pneumophila</italic> isolates from the hospital environment along with a high percentage of pathogenicity loci. Besides, certain STs may have an increased ability to cause legionellosis, thus requires specific infection control and prevention strategies whenever identified.</p>