Streptococcus castoreus, an uncommon group A Streptococcus in beavers

Corynebacterium ulcerans Infections in Eurasian Beavers (Castor fiber)

The Eurasian beaver (Castor fiber) has been reintroduced successfully in Germany since the 1990s. Since wildlife is an important source of zoonotic infectious diseases, monitoring of invasive and reintroduced species is crucial with respect to the One Health approach. Three Eurasian beavers were found dead in the German federal states of Bavaria, North Rhine-Westphalia and Baden-Wuerttemberg in 2015, 2021 and 2022, respectively. During post-mortem examinations, Corynebacterium (C.) ulcerans could be isolated from the abscesses of two beavers and from the lungs of one of the animals. Identification of the bacterial isolates at the species level was carried out by spectroscopic analysis using MALDI-TOF MS, FT-IR and biochemical profiles and were verified by molecular analysis based on 16-23S internal transcribed spacer (ITS) region sequencing. Molecular characterization of the C. ulcerans isolates using whole-genome sequencing (WGS) revealed a genome size of about 2.5 Mbp and a GC content of 53.4%. Multilocus sequence typing (MLST) analysis classified all three isolates as the sequence type ST-332. A minimum spanning tree (MST) based on cgMLST allelic profiles, including 1211 core genes of the sequenced C. ulcerans isolates, showed that the beaver-derived isolates clearly group on the branch of C. ulcerans with the closest relationship to each other, in close similarity to an isolate from a dog. Antibiotic susceptibility testing revealed resistance to clindamycin and, in one strain, to erythromycin according to EUCAST, while all isolates were susceptible to the other antimicrobials tested.

First Report of Streptococcus ruminantium in Wildlife: Phenotypic Differences with a Spanish Domestic Ruminant Isolate

Streptococcus ruminantium is a recent reclassification of the former Streptococcus suis serovar 33. Although knowledge about S. suis is extensive, information on S. ruminantium host range and pathogenic potential is still scarce. This bacterium has been isolated from lesions in domestic ruminants, but there are no reports in wild animals. Here, we provide information on lesions associated with S. ruminantium in Pyrenean chamois (Rupicapra pyrenaica) and domestic sheep from NE Spain, as well as phenotypic biopatterns and antimicrobial resistance (AMR) of the isolates. Overall, lesions caused by S. ruminantium were similar to those caused by S. suis, excluding polyserositis. Heterogeneity of the phenotypic profiles was observed within the S. ruminantium strains by VITEK-2, resulting in only two tests common to all S. ruminantium isolates and different from S. suis: Alpha-Galactosidase and Methyl-B-D-Glucopyranoside, both positive for S. suis and negative for S. ruminantium strains. Isolates from Pyrenean chamois were susceptible to all antimicrobials tested, except danofloxacin, whereas the domestic sheep isolate was resistant to tetracycline. In conclusion, S. ruminantium can cause infection and be associated with pathology in both wild and domestic ruminants. Due to its phenotypic diversity, a specific PCR is optimal for identification in routine diagnosis.

Streptococcus vicugnae sp. nov., isolated from faeces of alpacas (Vicugna pacos) and cattle (Bos taurus), Streptococcus zalophi sp. nov., and Streptococcus pacificus sp. nov., isolated from respiratory tract of California sea lions (Zalophus californianus)

Four novel independent strains of Streptococcus spp. were isolated from faeces of alpaca (SL1232^T), cattle (KCJ4950), and from respiratory tract of wild California sea lions (CSL7508^T, CSL7591^T). The strains were indole-, oxidase- and catalase-negative, non-spore-forming, non-motile Gram-positive cocci in short and long chains, facultative anaerobes. The 16S rRNA gene of SL1232^T and KCJ4950 shared 99.40-99.60% nucleotide similarity to strains of S. equinus, S. lutetiensis, S. infantarius, and the 16S rRNA gene of CSL7508^T and CSL7591^T demonstrated 98.72 and 98.92% similarity, respectively, to S. marimammalium. All other known Streptococcus species had the 16S rRNA gene sequence similarities of ≤95%. The genomes were sequenced for the novel strains. Average nucleotide identity (ANI) analysis for strains SL1232^T and KCJ4950, showed the highest similarity to S. equinus, S. lutetiensis, and S. infantarius with 85.21, 87.17, 88.47, 85.54, 87.47 and 88.89%, respectively, and strains CSL7508^T and CSL7591^T to S. marimammalium with 87.16 and 83.97%, respectively. Results of ANI were confirmed by pairwise digital DNA-DNA hybridization and phylogeny, which also revealed that the strains belong to three novel species of the genus Streptococcus. Phenotypical features of the novel species were in congruence with closely related members of the genus Streptococcus and gave negative reactions with the tested Lancefield serological groups (A-D, F and G). MALDI-TOF mass spectrometry supported identification of the species. Based on these data, we propose three novel species of the genus Streptococcus, for which the name Streptococcus vicugnae sp. nov. is proposed with the type strain SL1232^T (=NCTC 14341^T=DSM 110741^T=CCUG 74371^T), Streptococcus zalophi sp. nov. is proposed with the type strain CSL7508^T (=NCTC 14410^T=DSM 110742^T=CCUG 74374^T) and Streptococcus pacificus sp. nov. is proposed with the type strain CSL7591^T (=NCTC 14455^T=DSM 111148^T=CCUG 74655^T). The genome G+C content is 36.89, 34.85, and 35.34 % and draft genome sizes are 1906993, 1581094 and 1656080 bp for strains SL1232^T, CSL7508^T, and CSL7591^T, respectively.

Streptococcus catagoni sp. nov., isolated from the respiratory tract of diseased Chacoan peccaries (Catagonus wagneri)

Novel catalase-negative, Gram-stain-positive, beta-haemolytic, coccus-shaped organisms were isolated from Chacoan peccaries that died from respiratory disease. The initial API 20 Strep profiles suggested Streptococcus agalactiae with acceptable identification scores, but the 16S rRNA gene similarity (1548 bp) to available sequences of streptococci was below 98 %. Next taxa of the genus Streptococcus, displaying highest similarities to the strains from this study, were S. bovimastitidis NZ1587^T (97.5 %), S. iniae ATCC 29178^T (97.5 %), S. hongkongensis HKU30^T (97.4 %), S. parauberis DSM 6631^T (97.1 %), S. penaeicida CAIM 1838^T (97.1 %), S. pseudoporcinus DSM 18513^T (97.0 %), S. didelphis DSM 15616^T (96.6 %), S. ictaluri 707-05^T (96.6 %), S. uberis JCM 5709^T (96.5 %) and S. porcinus NCTC 10999^T (96.4 %). All other Streptococcus species had sequence similarities of below 96.4 %. A sodA gene as well as whole genome-based core genome phylogeny of three representative strains and 145 available Streptococcus genomes confirmed the unique taxonomic position. Interstrain average nucleotide identity (ANI) and amino acid identity (AAI) values were high (ANI >96 %; AAI 100%), but for other streptococci clearly below the proposed species boundary of 95-96 % (ANI <75 %; AAI <83 %). Results were confirmed by genome-to-genome distance calculations. Pairwise digital DNA-DNA hybridization estimates were high (>90 %) between the novel strains, but well below the species boundary of 70 % for closely related Streptococcus type strains (23.5-19.7 %). Phenotypic properties as obtained from extended biochemical profiles and MALDI-TOF mass spectrometry supported the outstanding rank. Based on the presented molecular and physiological data of the six strains, we propose a novel taxon for which we suggest the name Streptococcus catagoni sp. nov. with the type strain 99-1/2017^T (=DSM 110457^T=CCUG 74072^T) and five reference strains.