A set of 25 strains belonging to clade V of Mannheimia mainly isolated from cattle was investigated and is proposed to represent Mannheimia indoligenes sp. nov. The species can be separated from the other validly published species of the genus by pheno- and genotype. Only indole separates M. indoligenes and Mannheimia varigena while two to seven characters separate M. indoligenes from other species of Mannheimia . Thirteen strains belonging to biogroups 6, 7, 8C, 9, 10, 12 and UG5 formed a monophyletic group based on 16S rRNA gene sequence comparisons with 98–100 % similarity. Eight of these strains were further included in the whole genome comparison. Digital DNA–DNA hybridization showed that the similarities between the suggested type strain M14.4 T and the other strains of M. indoligenes were 62.9 % or higher. The average nucleotide identity was 95.5 % or higher between M14.4 T and the other strains of the species. The rpoB gene sequence similarity was 95–100 % within M. indoligenes . MALDI-TOF allowed a clear separation from other Mannheimia species further supporting classification as a novel species and making it the diagnostic identification tool of choice for M. indoligenes . The type strain is M14.4 T (=CCUG 77347 T =DSM 116804 T ) isolated from a cattle tongue in Scotland.
Five strains of an unidentified Gram-positive, catalase-negative, chain-forming coccus-shaped organism recovered from sheep in Scotland were characterized using phenotypic and molecular taxonomic methods. Based on morphological and biochemical criteria, the strains were tentatively identified as streptococci but they did not appear to correspond to any recognised species of the genus. Comparative 16S rRNA gene sequencing showed the strains were highly related to each other and confirmed their placement in the genus Streptococcus, with a maximum nucleotide identity of around 97 % to extant species. Best matches were with Streptococcus hillyeri followed by Streptococcus porci. Average nucleotide identity and in silico DNA-DNA hybridization values determined from whole-genome sequence were also consistent with the group representing a novel species. Best matches, again seen to S. hillyeri, followed by S. porci and S. plurextorum, were below accepted cut-off values for species delineation. Based on biochemical criteria and molecular genetic evidence, it is proposed that the unknown isolates from sheep be assigned to a new species of the genus Streptococcus as Streptococcus caledonicus sp. nov. The type strain of Streptococcus caledonicus is S784/96/1T=CCUG 73951T=NCTC 14363T.
Two strains of a previously undescribed Arcanobacterium-like bacterium were isolated from a dead harbour porpoise and a dead sallow deer. Biochemical testing and PAGE analysis of whole-cell proteins indicated that the strains were phenotypically closely related to each other and distinct from previously described Actinomyces and Arcanobacterium species. Comparative 16S rRNA gene sequencing studies showed the bacterium to be a hitherto unknown subline within the genus Arcanobacterium. Based on phylogenetic and phenotypic evidence, it is proposed that the unknown bacterium be classified as Arcanobacterium pluranimalium sp. nov. The type strain of Arcanobacterium pluranimalium is CCUG 42575T (= CIP 106442T).
Escherichia coli O86:K61 has long been associated with outbreaks of infantile diarrhea in humans and with diarrheal disease in many animal species. Studies in the late 1990s identified E. coli O86:K61 as the cause of mortality in a variety of wild birds, and in this study, 34 E. coli O86:K61 isolates were examined. All of the isolates were nonmotile, but most elaborated at least two morphologically distinct surface appendages that were confirmed to be type 1 and curli fimbriae. Thirty-three isolates were positive for the eaeA gene encoding a gamma type of intimin. No phenotypic or genotypic evidence was obtained for elaboration of Shiga-like toxins, but most isolates possessed the gene coding for the cytolethal distending toxin. Five isolates were selected for adherence assays performed with tissue explants and HEp-2 cells, and four of these strains produced attaching and effacing lesions on HEp-2 cells and invaded the cells, as determined by transmission electron microscopy. Two of the five isolates were inoculated orally into 1-day-old specific-pathogen-free chicks, and both of these isolates colonized, invaded, and persisted well in this model. Neither isolate produced attaching and effacing lesions in chicks, although some pathology was evident in the alimentary tract. No deaths were recorded in inoculated chicks. These findings are discussed in light of the possibility that wild birds are potential zoonotic reservoirs of attaching and effacing E. coli.
Diphtheria is a potentially life-threatening infection in humans. The three species capable of causing diphtheria are: Corynebacterium diphtheriae , C. ulcerans and C. pseudotuberculosis . Although UK cases are rare, recently there has been an increase in reported toxigenic C. ulceransassociated with companion animals. Potentially toxigenic corynebacteria are sent to the National Reference Laboratory, Public Health England (PHE), London, UK for species confirmation, determination of presence of the diphtheria toxin gene by real-time PCR, and confirmation of toxin expression by the Elek test. We reviewed submissions of C. ulcerans between January 2006 and November 2019. Fifty-three isolates of toxigenic C. ulcerans were received, 29 from humans and 24 from animals. The most common animal hosts were dogs (15) and cats (7), but isolates were also received from a horse and a captive rhinoceros. Multi-locus sequence typing (MLST) data were derived from whole genome sequencing. In three human cases, C. ulcerans was isolated from companion animals and in all three, typing data supported an epidemiological link between human and animal hosts. The sequence types (STs) for these linked isolates were ST331 (human and dog, human and cat) and ST551 (human and cat). Although MLST data are limited, the finding of the same ST (ST331) from canine and feline sources indicates that strains can be carried by both hosts. Management of diphtheria cases is an important public health issue. Typing data can support epidemiological linkage and identify possible sources, allowing the potential intervention and treatment of animals thus avoiding onward transmission.
Extension of known ecological niches of Brucella has included the description of two novel species from marine mammals. Brucella pinnipedialis is associated predominantly with seals, while two major Brucella ceti clades, most commonly associated with porpoises or dolphins respectively, have been identified. To date there has been limited characterisation of Brucella isolates obtained from marine mammals outside Northern European waters, including North American waters. To address this gap, and extend knowledge of the global population structure and host associations of these Brucella species, 61 isolates from marine mammals inhabiting North American waters were subject to molecular and phenotypic characterisation enabling comparison with existing European isolates. The majority of isolates represent genotypes previously described in Europe although novel genotypes were identified in both B. ceti clades. Harp seals were found to carry B. pinnipedialis genotypes previously confined to hooded seals among a diverse repertoire of sequence types (STs) associated with this species. For the first time Brucella isolates were characterised from beluga whales and found to represent a number of distinct B. pinnipedialis genotypes. In addition the known host range of ST27 was extended with the identification of this ST from California sea lion samples. Finally the performance of the frequently used diagnostic tool Bruce-ladder, in differentiating B. ceti and B. pinnipedialis, was critically assessed based on improved knowledge of the global population structure of Brucella associated with marine mammals.
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