Draft Genome Sequences of Seven Legionella pneumophila Isolates from a Hot Water System of a Large Building

Gomez-Alvarez, Vicente; Boczek, Laura A.; King, Dawn; Pemberton, Adin; Pfaller, Stacy; Rodgers, Mark R.; Santo-Domingo, Jorge; Revetta, Randy P.

doi:10.1128/mra.00384-19

Cited by 3 publications

(4 citation statements)

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“…Sequence-based typing (SBT) analysis was performed in silico with legsta and multi-locus sequence typing (mlst) as described previously [ 94 ]. The phylogenetic tree was constructed combining the sequenced genomes from this study and a set of closely related genomes.…”

Section: Methodsmentioning

confidence: 99%

Legionella Diversity and Spatiotemporal Variation in the Occurrence of Opportunistic Pathogens within a Large Building Water System

et al. 2020

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Understanding Legionella survival mechanisms within building water systems (BWSs) is challenging due to varying engineering, operational, and water quality characteristics unique to each system. This study aimed to evaluate Legionella, mycobacteria, and free-living amoebae occurrence within a BWS over 18–28 months at six locations differing in plumbing material and potable water age, quality, and usage. A total of 114 bulk water and 57 biofilm samples were analyzed. Legionella culturability fluctuated seasonally with most culture-positive samples being collected during the winter compared to the spring, summer, and fall months. Positive and negative correlations between Legionella and L. pneumophila occurrence and other physiochemical and microbial water quality parameters varied between location and sample types. Whole genome sequencing of 19 presumptive Legionella isolates, from four locations across three time points, identified nine isolates as L. pneumophila serogroup (sg) 1 sequence-type (ST) 1; three as L. pneumophila sg5 ST1950 and ST2037; six as L. feeleii; and one as Ochrobactrum. Results showed the presence of a diverse Legionella population with consistent and sporadic occurrence at four and two locations, respectively. Viewed collectively with similar studies, this information will enable a better understanding of the engineering, operational, and water quality parameters supporting Legionella growth within BWSs.

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Section: Methodsmentioning

confidence: 99%

Legionella Diversity and Spatiotemporal Variation in the Occurrence of Opportunistic Pathogens within a Large Building Water System

et al. 2020

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“…DnaK M94I was identified in HA-1, HA-2, and HA-6 as well as in 64 other isolates ( Table S2 ). Metadata associated with the sequence assemblies did not support an enrichment of this mutation in isolates with an environmental experience of heat-shock exposure ( 69 , 70 ). Instead, the distribution of DnaK M94I was contingent on the isolates’ clustering in the subpopulation structure of the species ( 71 ).…”

Section: Resultsmentioning

confidence: 89%

Development of heat-shock resistance in Legionella pneumophila modeled by experimental evolution

Liang,

Cameron,

Faucher

2023

Appl Environ Microbiol

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Because it can grow in buildings with complex hot water distribution systems (HWDS), healthcare facilities recognize the waterborne bacterium Legionella pneumophila as a major nosocomial infection threat and often try to clear the systems with a pasteurization process known as superheat-and-flush. After this treatment, many facilities find that the contaminating populations slowly recover, suggesting the possibility of in situ evolution favoring increased survival in high-temperature conditions. To mimic this process in a controlled environment, an adaptive laboratory evolution model was used to select a wild-type strain of L. pneumophila for survival to transient exposures to temperatures characteristic of routine hot water use or failed pasteurization processes in HWDS. Over their evolution, these populations became insensitive to exposure to 55°C and developed the ability to survive short exposures to 59°C heat shock. Heat-adapted lineages maintained a higher expression of heat-shock genes during low-temperature incubation in freshwater, suggesting a pre-adaptation to heat stress. Although there were distinct mutation profiles in each of the heat-adapted lineages, each acquired multiple mutations in the DnaJ/DnaK/ClpB disaggregase complex, as well as mutations in chaperone htpG and protease clpX . These mutations were specific to heat-shock survival and were not seen in control lineages included in the experimental model without exposure to heat shock. This study supports in situ observations of adaptation to heat stress and demonstrates the potential of L. pneumophila to develop resistance to control measures. IMPORTANCE As a bacterium that thrives in warm water ecosystems, Legionella pneumophila is a key factor motivating regulations on hot water systems. Two major measures to control Legionella are high circulating temperatures intended to curtail growth and the use of superheat-and-flush pasteurization processes to eliminate established populations. Facilities often suffer recolonization of their hot water systems; hospitals are particularly at risk due to the severe nosocomial pneumoniae caused by Legionella . To understand these long-term survivors, we have used an adaptive laboratory evolution model to replicate this process. We find major differences between the mutational profiles of heat-adapted and heat-naïve L. pneumophila populations including mutations in major heat-shock genes like chaperones and proteases. This model demonstrates that well-validated treatment protocols are needed to clear contaminated systems and—in an analog to antibiotic resistance—the importance of complete eradication of the resident population to prevent selection for more persistent bacteria.

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“…At the time of publication, monthly sampling events confirmed the presence of L. pneumophila in the drinking water system. A 100-ml water sample was concentrated by membrane filtration (0.2 μm), and the subsequent selective recovery of L. pneumophila was performed as described by Gomez-Alvarez et al ( 7 ). Briefly, the concentrate was resuspended in 5 ml of Butterfield's phosphate buffer, and 100 μl was cultured on buffered CYE selective agar (catalogue number R110107; Remel, Lenexa, KS) for 5 days at 35°C.…”

Section: Announcementmentioning

confidence: 99%

“…A genomic library was prepared using the Nextera XT index kit (Illumina, Inc., San Diego, CA) and sequenced on the Illumina HiSeq 4000 platform (paired-end 150-nucleotide [nt] reads). Read processing was performed as described previously ( 7 ); short-read libraries were cleaned of adapters and phiX artifacts, error corrected, normalized (≤100×), and filtered to a minimum length of 100 nt (BBMap v38.67; ktrim=r k=23 mink=11 hdist=1 tbo tpe maxns=0 trimq=10 qtrim=r maq=12 minlength=100 ecco=t eccc=t ecct=t target=100). A long-read library was prepared using the ligation sequencing kit (1D SQK-LSK109) and the native barcoding kit (EXP-NBD104) on a MinION device (Oxford Nanopore Technologies [ONT], Inc., Oxford, UK).…”

Section: Announcementmentioning

confidence: 99%

Closed Genome and Plasmid Sequences of Legionella pneumophila AW-13-4, Isolated from a Hot Water Loop System of a Large Occupational Building

Gomez-Alvarez

Boczek

Raffenberg

et al. 2021

Microbiol Resour Announc

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Draft Genome Sequences of Seven Legionella pneumophila Isolates from a Hot Water System of a Large Building

Abstract: Public health data show that a significant fraction of the nation’s waterborne disease outbreaks are attributable to premise plumbing. We report the draft genome sequences of seven Legionella pneumophila serogroup 1 isolates from hot water lines of a large building.

Cited by 3 publications

References 18 publications

Legionella Diversity and Spatiotemporal Variation in the Occurrence of Opportunistic Pathogens within a Large Building Water System

Legionella Diversity and Spatiotemporal Variation in the Occurrence of Opportunistic Pathogens within a Large Building Water System

Development of heat-shock resistance in Legionella pneumophila modeled by experimental evolution

Closed Genome and Plasmid Sequences of Legionella pneumophila AW-13-4, Isolated from a Hot Water Loop System of a Large Occupational Building

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