Severe cochlear inflammation and vestibular syndrome in an experimental model of Streptococcus suis infection in mice

Abstract

Hearing impairment is a common and frequently permanent sequel of Streptococcus suis meningitis in humans. Nevertheless, mechanisms underlying the development of cochlear damage have not been addressed so far. In the present work, we characterized a mouse model of suppurative labyrinthitis and meningitis induced by a systemic infection with S. suis and studied the impact of the injected bacterial dosage on the progression of such inflammatory events. We observed that high infection doses of bacteria lead to sustained bacteremia, with an increase in the permeability of the blood-labyrinth and blood-brain barriers, causing suppurative labyrinthitis and meningitis, respectively. However, in mice infected with a low dose of S. suis, bacteria disappeared quickly from blood, hence, cochlear inflammation and meningitis were not consistent features. This model of S. suis infection seems ideal to evaluate novel drugs that may help alleviate the negative consequences of such important sequelae of S. suis-induced meningitis and labyrinthitis.

Capsular Sialic Acid of Streptococcus suis Serotype 2 Binds to Swine Influenza Virus and Enhances Bacterial Interactions with Virus-Infected Tracheal Epithelial Cells

“…In swine, S. suis is mainly transmitted by aerosols, and airborne transmission among pigs has been clearly demonstrated (34). S. suis cells play a certain role in mixed respiratory infections, although it is not considered a primary cause of swine pneumonia (1), indicating that it also uses the respiratory tract as a transient passage before reaching the bloodstream and causing bacteremia, which is essential for the pathogen to cause meningitis (35). The actual early mechanisms used by this pathogen to interact with epithelial cells and to further invade the bloodstream are poorly understood.…”

Streptococcus suis: a re-emerging pathogen associated with occupational exposure to pigs or pork products. Part II – Pathogenesis

“…According to these authors, rather cochlear sepsis, resulting from passage of the organism from the sub-arachnoid space to the perilymph via the cochlear aqueduct, might be primarily responsible for the hearing loss complicating bacterial meningitis caused by S. suis. This view has been supported by the results obtained by Dominguez-Punaro et al [15], who observed that mice infected with a high doses of S. suis bacteria developed sustained bacteraemia, with an increase in the permeability of the blood-labyrinth and blood-brain barriers, resulting in suppurative labyrinthitis and meningitis.…”

Use of Tetravalent Galabiose for Inhibition of Streptococcus Suis Serotype 2 Infection in a Mouse Model

“…The pathogenesis and virulence mechanisms involved in S. suis serotype 2 infections are still unclear, although a number of mouse models have been developed [6,25,26,28,29,31] and despite the fact that in vitro assays examining specific virulence mechanisms have been generated [32,33,34,35]. …”

“…A number of experimental animal models for evaluation of virulence of S. suis serotype 2 isolates have been developed in mice and pigs [25]. At present there is no standardized animal model for studying S. suis infection, and this has caused some confusion in designating strains as virulent or non-virulent.…”

“…At present there is no standardized animal model for studying S. suis infection, and this has caused some confusion in designating strains as virulent or non-virulent. In several studies, the mouse has proven to be a suitable animal model for the infection with S. suis serotype 2, and one of the early experiments by Williams and co-workers determined that the behavior of the bacterium in mice resembled what had previously been reported in pigs [25,26]. Different murine models for the study of S. suis infections have been developed involving different experimental setups [27,28,29].…”