Fulminant Streptococcus suis infection detected on peripheral blood smear: A case report.

Streptococcus suis, a gram-positive coccus, is recognized as an emerging zoonotic pathogen that causes serious infections in humans, such as bacterial meningitis and sepsis, with poor outcomes. The pathogen is known to be transmitted through the consumption of raw pork or occupational exposure to pigs. A previously healthy 38-year-old woman with occupational exposure to raw pork was presented to our emergency department with a clinical diagnosis of rapidly progressive septic shock. Peripheral blood smears detected chains of cocci inside granulocytes, which led to the early recognition of gram-positive cocci in short chains before the blood culture test results. Blood cultures later tested positive for S. suis serotype 2. The patient's condition deteriorated despite aggressive resuscitative measures including antibiotics, vasopressors, multiple blood transfusions, mechanical ventilation, and renal replacement therapy. Initiation of veno-arterial extracorporeal membrane oxygenation was ineffective, and the patient died 16 h after admission. The identification of bacteria in the peripheral blood smear indicated an overwhelming infection and led to the rapid recognition of bacteremia. Our report aims to raise awareness about fatal zoonotic pathogens and to promote the unique role of peripheral blood smears that could provide preliminary diagnostic information before blood culture results.

The first case report of infective endocarditis caused by Gemella taiwanensis.

Gemella is a facultative anaerobic Gram-positive coccus and a rare cause of infective endocarditis (IE). Gram staining may eventually misidentify the organism, which tends to easily decolorize and manifest as either Gram-negative or Gram-variable. Commercial biochemical tests are often used to identify Gemella, but the methods they employ sometimes lack accuracy. A 52-year-old woman was diagnosed with Gemella taiwanensis IE after initial identification of the pathogen as Gemella haemolysans using biochemical tests combined with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). She was treated successfully with penicillin, gentamicin, and mitral valve replacement. To our knowledge, this is the first case of IE confirmed by 16S rRNA gene and groEL sequencing to have been caused by G. taiwanensis. The accurate diagnosis of rare or difficult-to-identify pathogens is a major challenge for clinical microbiological laboratories. The concurrent use of molecular methods could lead to the recognition of new or different pathogens.