Infective Endocarditis Caused by Extended-Spectrum Beta-Lactamase-Producing Escherichia coli: A Case Report

Tsuneaki Kenzaka,1,2 Yuto Shinkura,1 Shizuo Kayama,3– 5 Liansheng Yu,3– 5 Sayoko Kawakami,3 Motoyuki Sugai,3– 5 Satoru Kawasaki1 1Department of Internal Medicine, Hyogo Prefectural Tamba Medical Center, Tanba, Japan; 2Division of Community Medicine and Career Development, Kobe University Graduate School of Medicine, Kobe, Japan; 3Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Tokyo, Japan; 4Department of Antimicrobial Resistance, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; 5Project Research Center for Nosocomial Infectious Diseases, Hiroshima University, Hiroshima, JapanCorrespondence: Tsuneaki KenzakaDivision of Community Medicine and Career Development, Kobe University Graduate School of Medicine, 2-1-5, Arata-cho, Hyogo-ku, Kobe, Hyogo, 652-0032, JapanTel +81-78-382-6732Fax +81-78-382-6283Email smile.kenzaka@jichi.ac.jpIntroduction: Extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) reportedly accounts for > 20% of E. coli infections and 2.0% of infective endocarditis cases. Nonetheless, there is a global paucity of reports on infective endocarditis caused by ESBL-EC.Case: An 83-year-old Japanese man who underwent mitral annuloplasty for mitral valve prolapse 5 years ago developed a fever of 38.5°C. The patient was hospitalized the first time for pyelonephritis and bacteremia due to ESBL-EC and treated successfully with the antimicrobial meropenem for 14 days. Two days after discharge, however, the patient was re-admitted with bacteremia due to ESBL-EC. He was treated successfully with the antimicrobial cefmetazole for 14 days. The patient was admitted to our institution for a third time due to bacteremia again, a day after discharge following meropenem antibiotic therapy. Transesophageal echocardiography showed vegetation in the anterior mitral valve annulus. Magnetic resonance imaging of the head showed septic cerebral embolism. The patient was diagnosed with infective endocarditis due to ESBL-EC and underwent mitral valve replacement. After 6 weeks of antibiotic therapy with meropenem and tobramycin, the patient recovered completely. The causative E. coli strain MS6396 was identified as the E. coli clone ST131 by multilocus sequence typing and confirmed the presence of blaCTX-M-27 ESBL gene.Conclusion: Only six cases of infective endocarditis associated with ESBL-EC have been reported in the past. Moreover, this is the first report of a patient with infective endocarditis bacteriologically or genetically analyzed for ESBL-EC. In future, factors that may cause infective endocarditis in ESBL-EC infections may be clarified through more thorough bacteriological/genetic analyses of ESBL-EC.Keywords: blaCTX-M-27 ESBL, ST131, E. coli, meropenem, infective endocarditis, bacteremia