S. suis is an important pathogen that causes various diseases in pigs, including meningitis, septicemia, pneumonia, endocarditis, and arthritis [
4]. Human infection with
S. suis has been reported in many countries, and several outbreaks have occurred in China, which has raised great public concern regarding
S. suis as an emerging pathogen [
1].
S. suis infection in humans has mainly been reported in countries with high population densities of pigs. A matched case-control study on the risk factors for human infection in Sichuan Province, where outbreaks have occurred, indicated that slaughtering, cutting carcasses of, and processing sick or dead pigs are the main risk factors for
S. suis infection in humans [
7]. Factors such as occupational or household exposure to pigs or pork may not be considered as risk factors. In some cases reported in Hong Kong and Vietnam, the patients did not report any exposure to pork [
8,
9]. In the present case, the patient was from Chungcheong Province in South Korea; many pig farms were present around her house, but she was not specifically exposed to pigs or pork. Pork is the main type of meat in Korea, and housewives may come in contact with raw pork during cooking. A study has reported that
S. suis was isolated from 55 of 406 palatine tonsillar samples of pigs in Korea [
10].
S. suis causes a systemic infection in humans, and meningitis is the most common and serious clinical manifestation [
2,
11]. Hearing loss is a frequent complication and has been reported in about half of the patients [
3]. Bacteremia is also a common finding; a report on the outbreaks in China showed a high frequency of severe sepsis with high mortality rate [
6]. Other clinical manifestations of
S. suis infection include endocarditis, pyogenic arthritis, and peritonitis [
12-
15]. In the present case, the patient had arthritis and bacteremia, and joint fluid and blood culture showed the growth of
S. suis. Although a CSF sample could not be obtained for culture, meningitis due to
S. suis was suspected by her clinical features of severe headache and neck stiffness. However, the results of CSF analysis, such as WBC count and glucose and lactate levels, were not consistent with bacterial meningitis. A previous report on cases in Vietnam showed that
S. suis is susceptible to penicillin, ceftriaxone, and vancomycin, and some strains are resistant to tetracycline (83.2% of the isolates), erythromycin (20%), and chloramphenicol (3.3%) [
8].