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

M Lourdes Abarca,Carlos Neila-Ibáñez,Enric Vidal,Virginia Aragon,Xavier Fernández Aguilar,Ester Pintado,Roser Velarde

doi:10.3390/microbiolres13010008

M Lourdes Abarca, Carlos Neila-Ibáñez + Show 5 more

Open Access

https://doi.org/10.3390/microbiolres13010008

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Abstract

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.

Highlights

In the case of the domestic sheep, where S. ruminantium CCGMV928 was isolated from, multiple white to yellowish nodular suppurative lesions of 0.5 to 2 cm in diameter were detected in the liver (Figure 2A,B)
The classified as S. suis serovar 33, has been assessed for the first time in wildlife
The diverse diverse ERIC-PCR profiles and biochemical characteristics among strains isolated in PyrERIC-PCR profiles and biochemical characteristics among strains isolated in Pyrenean enean chamois in different years suggest a high S. ruminantium diversity in NE Spain

Summary

Introduction

Serovar 33 of Streptococcus suis, one of the most important swine bacterial pathogens worldwide [3], has recently been reclassified as a species nova, Streptococcus ruminantium [4]. All S. ruminantium isolates, except two that were recovered from a milk-feeding robot and a bulk tank milk [5,6], have been isolated from domestic ruminants (cattle, sheep, and goat), but none from wildlife species. Despite the lack of epidemiological information, S. ruminantium could be a colonizer of the upper respiratory tract of ruminants, similar to S. suis in piglets. S. ruminantium by partial 16S rRNA gene sequence and specific PCR These strains represent the first report of S. ruminantium in wildlife worldwide and the first report in domestic ruminants in Spain

Main Necropsy Findings

Isolates Characterization

Histopathology

Results

Discussion