Bacteraemia Caused by Kytococcus schroeteri in a Pneumonia Patient

Kytococci are a part of the normal skin microbiota of humans and can cause infections, particularly in patients with prosthetic devices or immunodeficiency. Due to insufficient identification methods and an intrinsic resistance to several β-lactams, infections due to Kytococci are a challenge to clinical microbiologists and clinicians]. Here, we report the first Korean case of bacteraemia due to Kytococcus schroeteri in a patient with pneumonia.

 A 55-year-old man was admitted to a tertiary-care hospital in Seoul, Korea, for evaluation of fever and dyspnea. The patient had no history of hypertension or diabetes mellitus. The patient had been living in a sanatorium because of quadriplegia resulting from a cerebral infarction diagnosed at age 20 years. Laboratory tests showed a leukocyte count of 12.89 × 109/L (neutrophil 83.6%) and a C-reactive protein level of 156.0 mg/L (normal range, 0.1-6.0 mg/L). A chest X-ray showed a large amount of pleural effusion and marked peribronchovascular markings in the left lung. Percutaneous catheter drainage of the pleural effusion was performed, but the pleural fluid culture did not yield any bacterial growth. The predominant organism of sputum cultures was α-Streptococcus species, which is thought to be part of the normal flora. A blood culture performed the day the patient was admitted showed Gram-positive cocci growth (isolate GNKS01) in an anaerobic blood culture vial, one of six total (three aerobic and three anaerobic).

Subculture of the blood culture fluid yielded small, slightly yellowpigmented, convex, catalase-positive, and non-haemolytic colonies on 5% sheep blood agar after 24 h of incubation in 6% CO2 at 35°C. Routine Gram staining of the smeared preparation showed Gram-variable cocci in pairs or tetrads. However, the isolate appeared to be Grampositive after shortening the destaining time from 3–4 sec to 1–2 sec. Morphologic evaluation using scanning electron microscopy (FE SEM S-800, Hitachi, Tokyo, Japan) showed spherical cells (1.0–1.5 μm in diameter) in pairs or tetrads.