Isolation of Kocuria Rosae in Blood Culture of a Patient With Unspecified Bronchopneumonia

Bacteria of the genus Kocuria spp., although part of the normal human commensal flora of the skin and mucous membranes, have shown increasing pathogenic potential, including in immunocompetent hosts. Reported infections range from urinary infections, peritonitis and endocarditis to mediastinitis. This case report details an atypical bronchopneumonia caused by Kocuria rosae, emphasizing the importance of precise microbiological diagnosis. A 19-year-old female patient presented to the emergency department with progressively severe flu-like symptoms, asthenia and loss of appetite. Her history included bronchial asthma since age 8, on continuous medication, with no allergies or previous comorbidities. On physical examination, decreased vesicular breath sounds with rhonchi and crackles at the left lung base were auscultated. Initial laboratory tests showed leukocytosis with left shift and elevated CRP. Viral panel for COVID-19 and influenza was negative. Chest CT revealed extensive consolidation in the left lower lobe with air bronchograms, surrounded by ground-glass opacities. Small centrilobular nodular ground-glass opacities were also noted in the right upper and lower lobes. Blood culture (BD BACTEC®) identified K. rosae with positivity in 10 hours. However, antimicrobial susceptibility testing was not performed due to lack of standardized methodology for this microorganism in current protocols. This limitation prevents precise determination of in vitro antimicrobial susceptibility and optimization of therapy, highlighting the need for further studies to establish standards. The patient was initially admitted to the ICU for 5 days and later transferred to the ward. Treatment included, sequentially, ceftriaxone (1g/18 days), sodium oxacillin (500 mg/8 days), azithromycin (500 mg/5 days) and linezolid (600 mg/10 days), in addition to respiratory physiotherapy. The final diagnosis was unspecified bronchopneumonia. The patient showed progressive clinical improvement with antibiotic therapy and physiotherapy, and was discharged on day 18 of hospitalization. This is the first known case of nonspecific bronchopneumonia caused by K. rosae. Blood culture is crucial for diagnosis. Reporting such rare cases is vital to guide more precise treatment, especially given the limited literature. Imaging studies are also important to confirm diagnosis and determine therapy duration.