Long-term survival of virulent tularemia pathogens outside a host in conditions that mimic natural aquatic environments.

Long-term survival of virulent tularemia pathogens outside a host in conditions that mimic natural aquatic environments. Appl Environ Microbiol. 2021 Jan 04;: Authors: Golovliov I, Bäckman S, Granberg M, Salomonsson E, Lundmark E, Näslund J, Busch JD, Birdsell D, Sahl JW, Wagner DM, Johansson A, Forsman M, Thelaus J Abstract Francisella tularensis, causative agent of the zoonotic disease tularemia, can cause seasonal outbreaks of acute febrile illness in humans with disease peaks in late summer to autumn. Interestingly, its mechanisms for environmental persistence between outbreaks are poorly understood. One hypothesis is that F. tularensis forms biofilm in aquatic environments. We utilized two fully virulent wild type strains: FSC200 (F. tularensis subsp. holarctica) and Schu S4 (F. tularensis subsp. tularensis); and three control strains: the attenuated Live Vaccine Strain (LVS; F. tularensis subsp. holarctica), a Schu S4 ΔwbtI mutant that is documented to form biofilms, and the low virulence U112 strain of the closely-related species Francisella novicida Strains were incubated in saline solution (0.9% NaCl) microcosms for 24 weeks at both 4°C and 20°C whereupon viability and biofilm formation were measured. These temperatures were selected to approximate winter and summer temperatures of fresh water in Scandinavia, respectively. U112 and Schu S4 ΔwbtI formed biofilms, but F. tularensis strains FSC200, Schu S4, and LVS did no...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research