Long-term outcomes of patients with Streptococcus suis infection in Viet Nam: A case-control study

OBJECTIVES: Streptococcus suis is a zoonotic cause of severe meningitis and sepsis in humans. We aimed to assess the long-term outcomes in patients who survived S. suis infection, in particular the progress and impact of vestibulocochlear sequelae. METHODS: This case-control study evaluated outcomes of S. suis infection at discharge and 3 and 9 months post-discharge for 47 prospectively enrolled cases and at 11–34 months for 31 retrospectively enrolled cases. Outcomes in patients were compared to 270 controls matched for age, sex and residency. RESULTS: The prevalence ratio (PR) of moderate-to-complete hearing loss was 5.0(95%CI 3.6–7.1) in cases at discharge, 3.7(2.5–5.4) at 3 months, 3.2(2.2–4.7) at 9 months, and 3.1(2.1–4.4) in retrospective cases compared to controls. Hearing improvement occurred mostly within the first 3 months with a change in hearing level of 11.1%(95%CI 7.0–15.1%) compared to discharge. The PR of vestibular dysfunction was 2.4(95%CI 1.7–3.3) at discharge, 2.2(1.4–3.1) at 3 months, 1.8(1.1–2.5) at 9 months, and 1.8(1.1–2.6) for retrospective cases compared to controls. Cases also indicated more problems with mobility, self-care and usual activities. CONCLUSIONS: Both hearing and vestibular impairment were common and persist in cases. Appropriate patient management strategies are needed to reduce the incidence and impact of these sequelae.