Phenotypic and Genotypic Characteristics of Members of the Genus Streptobacillus

Abstract

The genus Streptobacillus (S.) remained monotypic for almost 90 years until two new species were recently described. The type species, S. moniliformis, is one of the two etiological agents of rat bite fever, an under-diagnosed, worldwide occurring zoonosis. In a polyphasic approach field isolates and reference strains of S. moniliformis, S. hongkongensis, S. felis as well as divergent isolates were characterized by comparison of molecular data (n = 29) and from the majority also by their physiological as well as proteomic properties (n = 22). Based on growth-independent physiological profiling using VITEK2-compact, API ZYM and the Micronaut system fastidious growth-related difficulties could be overcome and streptobacilli could definitively be typed despite generally few differences. While differing in their isolation sites and dates, S. moniliformis isolates were found to possess almost identical spectra in matrix-assisted laser desorption ionization—time of flight mass spectrometry and Fourier transform infrared spectroscopy. Spectroscopic methods facilitated differentiation of S. moniliformis, S. hongkongensis and S. felis as well as one divergent isolate. Sequencing of 16S rRNA gene as well as functional genes groEL, recA and gyrB revealed only little intraspecific variability, but generally proved suitable for interspecies discrimination between all three taxa and two groups of divergent isolates.

Oceanivirga salmonicida gen. nov., sp. nov., a member of the Leptotrichiaceae isolated from Atlantic salmon (Salmo salar)

“…The major fatty acids C 16 : 0 , C 18 : 0 , C 18 : 1 !9c and C 18 : 2 !6,9c/ 18 : 0 ANTE were in accordance with those found for other members of the same family before (Eisenberg et al, 2016a, 2016b, Pins et al, 1996, Rowbotham, 1983, Rygg & Bruun, 1992 Table 2.…”

“…The evaluation of average nucleotide identity (ANI) analyses has proven to be well-suited for species delineation in Streptobacillus species (Eisenberg et al, 2015a(Eisenberg et al, , 2016b(Eisenberg et al, , 2016c and superior to DNA-DNA hybridization [DDH; Fig. 3.…”

Approved and novel strategies in diagnostics of rat bite fever and otherStreptobacillusinfections in humans and animals

“…13,16,18,22 Isolates from rats, mice, turkeys and humans were shown to belong to the same species. 31 Reports on possible infections in other livestock species date decades back into the last century. 17,20 However, as these strains are physically not available, reports are not fully in congruence with the genotypic and phenotypic properties of S. moniliformis.…”

“…31,51 In liquid media (e.g. tryptone soy broth) with addition of serum, streptobacillary growth can be detected after 2-7 d as typical "puff-ball" or "bread crumb-like" appearance.…”

“…24 We have recently employed another commercially available biochemical system (Merlin Micronaut, Bornheim, Germany) that was specifically adapted to the growth of Streptobacillus. 31 A choice of suitable biochemical tests is given in Table 1. In summary, Streptobacillus species can be indicated by a combination of growth and micromorphological characteristics together with some important, congruently negative resulting key reactions like cytochrome oxidase, catalase, urease, and nitrate reduction, Voges-Proskauer-reaction and indole production.…”