A Case of <i>Streptococcus iniae</i> Bacteremia Misdiagnosed by Biochemical Testing, but Diagnosed Definitively by Mass Spectrometry and 16S rRNA Gene Sequencing

A 76-year-old man was admitted to our hospital with a history of fever and difficulty in moving. Blood culture at admission grew β-hemolytic streptococci, identified by biochemical testing (BD CRYSTAL GP) as Streptococcus porcinus. S. porcinus is swine-derived streptococcal species, has been reported causative bacterium female genitourinary infection. The clinical background patient did not match the detected bacterium, so further MALDI-TOF MS 16S rRNA gene sequencing performed, which iniae. There are many case reports cellulitis caused this persons cooking infected fish, some arthritis, endocarditis, empyema. Reports iniae from Japan rare, since may be included identification databases, it might have correctly. In cases inconsistency between culture-identified organisms course, performing additional tests useful obtain an accurate diagnosis.