Carbapenem-Resistant Klebsiella pneumoniae Prosthetic Valve Endocarditis: A Feared Combination of Technology and Emerging Pathogens

Successful treatment of infective endocarditis due to pandrug-resistant Klebsiella pneumoniae with ceftazidime-avibactam and aztreonam

Pandrug-resistant (PDR) K. pneumoniae refractory to conventional treatment has been reported worldwide, causing a huge burden on the healthcare system, patient safety and the economy. K. pneumoniae is a prominent opportunistic pathogen causing hospital-acquired and community-acquired infections, but is rarely associated with infective endocarditis. Currently, there are sparse data guiding the optimal regimen when commonly used antibiotics fail, notably for the treatment of endocarditis infections. Here we report our experience in treating a 40-year-old female with PDR K. pneumoniae infection of cardiovascular implantable electronic device (CIED) and right-sided infective endocarditis. Initial susceptibility testing of the incriminated pathogen showed an apparent susceptibility to colistin but the prolonged course of colistin, gentamicin and meropenem did not resolve the infection. However, the synergistic combinations of aztreonam with ceftazidime-avibactam was able to overcome resistance and clear the infection rapidly. Genome sequencing showed that the PDR K. pneumoniae isolate belongs to the international high-risk clone ST14. The isolate harbored genes encoding NDM-1, OXA-48, CTX-M-14b, SHV-28 and OXA-1, explaining resistance to all β-lactams, including carbapenems. It carried the armA gene conferring resistance to all clinically important aminoglycosides and had alterations in GyrA, ParC and MgrB, explaining resistance to ciprofloxacin and colistin.

Infective endocarditis by Klebsiella species: a systematic review

This study aimed to systematically analyze all cases of infective endocarditis (IE) by Klebsiella species in the literature. A systematic review of PubMed, Scopus and Cochrane library (through 27^th January 2021) for studies providing epidemiological, clinical, microbiological as well as treatment data and outcomes of IE by Klebsiella species was performed. In this review, a total of 66 studies were included, providing data for 67 patients. A prosthetic valve was present in 16.4%, while the most common causative pathogen was K. pneumoniae followed by K. oxytoca. The aortic valve was the most commonly infected intracardiac site, followed by the mitral valve. The diagnosis was based on transthoracic echocardiography in 46.2%, while the diagnosis was set at autopsy in 9.2% of included patients. Blood cultures were positive in 93.8%. Fever and sepsis were the most frequent clinical presentations, followed by embolic phenomena, paravalvular abscess, and heart failure. Cephalosporins, aminoglycosides, and carbapenems were the most frequently used antimicrobials. Surgical treatment along with antimicrobials was performed in 37.3% of included patients. Clinical cure was noted in 80.3%, while the overall mortality was 19.4%. Infection at the aortic valve was independently associated with mortality by IE. This systematic review gives a comprehensive description of IE by Klebsiella and provides information on epidemiology, clinical manifestations, therapeutic strategies and their outcomes.