Streptococcus suis Infection and Hearing Loss

Abstract

Streptococcus suis is a zoonotic pathogen that can cause severe systemic infections in pigs and humans. Meningitis and septicemia are the critical clinical manifestations of the cases. Hearing loss (HL) reported by up to one-half of the patients is one of the striking features of the S. suis infection at presentation or a few days later (Wertheim et al., Clin Infect Dis 48:617–625, 2009; Huang et al., J Microbiol Immunol Infect 38:306–313, 2005). In addition to HL, vestibular dysfunction is another common complication among patients.

In recent years, the number of cases of S. suis infection has notably increased, with the highest prevalence in Southeast Asia, in which the swine consumption rate is high. Moreover, most patients are seen in Vietnam and Thailand (Rayanakorn et al., Sci Rep 8:13,358, 2018). The mortality among S. suis meningitis cases is lower than the cases caused by other causative agents; however, some authors reported a higher neurological sequelae ratio than other bacterial meningitis (Edmond et al., Lancet Infect Dis 10:317–328, 2010). Although pig or occupational exposure is not documented in all cases of S. suis infection, pigs and pig-related occupations, including farming and works involving meat processing, seem to be the significant risk factor for human S. suis infection. The risk of infection among the general population or other risk factors such as eating habits should not be underestimated for S. suis diseases (Rayanakorn et al., Sci Rep 8:13,358, 2018; Mai et al., Clin Infect Dis 2008;46:659–667).