Temperature-Dependent Growth Modeling of Environmental and Clinical Legionella pneumophila Multilocus Variable-Number Tandem-Repeat Analysis (MLVA) Genotypes.
Legionella pneumophilacauses waterborne infections resulting in severe pneumonia. High-resolution genotyping ofL. pneumophilaisolates can be achieved by multiple-locus variable-number tandem-repeat analysis (MLVA). Recently, we found that different MLVA genotypes ofL. pneumophiladominated different sites in a small drinking-water network, with a genotype-related temperature and abundance regime. The present study focuses on understanding the temperature-dependent growth kinetics of the genotypes that dominated the water network. Our aim was to model mathematically the influence of temperature on the growth kinetics of different environmental and clinicalL. pneumophilagenotypes and to compare it with the influence of their ecological niches. Environmental strains showed a distinct temperature preference, with significant differences among the growth kinetics of the three studied genotypes (Gt4, Gt6, and Gt15). Gt4 strains exhibited superior growth at lower temperatures (25 and 30°C), while Gt15 strains appeared to be best adapted to relatively higher temperatures (42 and 45°C). The temperature-dependent growth traits of the environmental genotypes were consistent with their distribution and temperature preferences in the water network. Clinical isolates exhibited significantly higher growth rates and reached higher maximal cell densities at 37°C and 42°C than the environmental strains. Further research on the growth preferences ofL. pneumophilaclinical and environmental genotypes will result in a better understanding of their ecological niches in drinking-water systems as well as in the human body.IMPORTANCELegionella pneumophilais a waterborne pathogen that threatens humans in developed countries. The bacteria inhabit natural and man-made freshwater environments. Here we demonstrate that different environmentalL. pneumophilagenotypes have different temperature-dependent growth kinetics. Moreover,Legionellastrains that belong to the same species but were isolated from environmental and clinical sources possess adaptations for growth at different temperatures. These growth preferences may influence the bacterial colonization at specific ecological niches within the drinking-water network. Adaptations for growth at human body temperatures may facilitate the abilities of someL. pneumophilastrains to infect and cause illness in humans. Our findings may be used as a tool to improveLegionellamonitoring in drinking-water networks. Risk assessment models for predicting the risk of legionellosis should take into account not onlyLegionellaconcentrations but also the temperature-dependent growth kinetics of the isolates.
Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel.
Yehonatan
Y
Sharaby
Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel.
Sarah
S
Rodríguez-Martínez
Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel.
Olga
O
Oks
Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany.
Marina
M
Pecellin
Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel.
Hila
H
Mizrahi
Clinical Microbiology Laboratory, Baruch Padeh Poriya Medical Center, Poriya, Israel.|The Faculty of Medicine in the Galilee, Bar-Ilan University, Galilee, Israel.
Avi
A
Peretz
Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany.
Ingrid
I
Brettar
Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany.
Manfred G
MG
Höfle
Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel mhalpern@research.haifa.ac.il.|Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, Tivon, Israel.
Malka
M
Halpern
D004777:Environment; D004783:Environmental Microbiology; D005838:Genotype; D006801:Humans; D007700:Kinetics; D016952:Legionella pneumophila / Q000235:genetics* / Q000254:growth & development* / Q000302:isolation & purification; D007877:Legionnaires' Disease / Q000382:microbiology; D018598:Minisatellite Repeats; D008954:Models, Biological; D013696:Temperature; D014871:Water Microbiology
Legionella pneumophila; MLVA; MLVA-8 genotyping; genotype; growth curve; growth kinetics; lag phase; log phase; mathematical models; stationary phase; temperature