OBJECTIVES

: To investigate on S. suis infection risk factors in human and to provide an update on evidences regarding clinical presentations and outcomes of the disease.

METHODS

: We searched eight relevant databases using the MeSH terms “Streptococcus suis” OR “Streptococcus suis AND infection” limited in human with no time nor language restriction. Articles were included if there were risk factors and also describing at least 4 patients. A meta-analysis was performed to identify the association between risk behaviors and S. suis infection.

RESULTS

: Out of 4,999 articles identified, 32 and 3 studies were included for systematic review and meta-analysis respectively. Among 32 included studies, a total of 1,454 Streptococcus suis cases were reported. S. suis patients were generally adult males and the elderly. The mean age ranged between 37 to 63 years. Meningitis was the most common clinical manifestation, and deafness was the most common sequelae found among survivors. The main risk factors associated with acquiring S. suis infection included raw pork consumption, pig-related occupation, pigs or pork exposure, and underlying diseases contributing to immunocompromised condition. History of skin injury during exposure or before infection was noted only a small percentage in some studies.

A total of 850 participants in 3 studies were included in meta-analysis. Raw pork consumption [pooled OR 8.24, 95% CI 2.30-29.50], exposure to pigs or pork [pooled OR 3.67, 95% CI 2.58-5.23], pig-related occupation [pooled OR 7.13, 95% CI 2.51, 20.24] and male sex [pooled OR 4.12, 95% CI 2.74-6.21] were found to be significantly associated with S. suis infection.

CONCLUSIONS

: Raw pork consumption, exposure to pigs or pork, pig-related occupation and male sex were significant risk factors in acquiring S. suis infection. Setting up an effective screening protocol and public health interventions would be effective to enhance understanding about the disease.