A CULTURE NEGATIVE ENDOCARDITIS CAUSED BY HYPERVIRULENT KLEBSIELLA PNEUMONIAE (ST23) DIAGNOSED FROM PCR OF VEGETATION

Abstract

Intro: Hypervirulent Klebsiella pneumoniae (hvKp) has been recognized an emerging pathogen that can cause life-threading infections including liver abscess, and endophthalmitis in Eastern Asia. However, clinical feature of infective endocarditis (IE) caused by hvKp is still unknown. Methods: Case Description; A 47-year-old male with no past medical history developed 3 days of fever, chills. He was admitted due to altered mental status (GCS E4V4M6), and his blood pressure was 134/91 mmHg, pulse rate was 109 bpm, and body temperature was 101.48°F (38.6°C). A petechiae on the conjunctiva, both palms, and left sole were found. Vegetation with perforation on the mitral valve was found by transthoracic echocardiogram. Blood cultures were negative with no current antimicrobial exposure. Infective endocarditis was confirmed according to modified Duke criteria. Intravenous vancomycin with cefepime was administrated as empiric antimicrobial therapy for blood culture- negative endocarditis (BCNE). A mitral valve replacement was performed according to the mitral valve perforation. The 16S rRNA gene sequence of vegetation from the mitral valve showed Klebsiella pneumoniae. The multi-locus sequence typing (MLST) revealed the sequence type (ST) 23, and virulence genes (rmpA, rpmA2) were also positive for PCR from the vegetation. Following valve replacement, an adenocarcinoma in descending colon was found and a left hemicolectomy was performed. Findings: Several reports showed that hvKp IE was caused by hematogenous spread from other foci such as pyogenic liver abscess. Although colon cancer could be the entry for hvKp for the current case, no abscesses including liver were found. Primary infective endocarditis caused by hvKp is extremely rare but underestimated in the case of BCNE. Conclusion: This is the first report of blood culture-negative hvKp endocarditis confirmed by 16S rRNA gene sequencing with virulence gene detection from vegetation. In the case of BCNE with rapid progression of unstable hemodynamic status, hvKp should be considered a causable pathogen.