Kluyvera Infections in Humans: A Systematic Review

Kluyvera species are Gram-negative rods, catalase-positive, oxidase-negative, and glucose-fermenting members of the Enterobacteriaceae family. Although often considered saprophytic, Kluyvera can cause opportunistic infections, particularly in immunocompromised individuals, with severe underlying medical conditions. The objective of this study was to identify and evaluate all published cases of human infections by Kluyvera spp., through a systematic literature review.

We searched PubMed and Scopus databases for articles providing data related to the epidemiology, clinical features, and microbiology of Kluyvera human infections.

In total, 73 studies provided information on 97 patients with Kluyvera infections. The mean age of the patients was 39.5 years and most (53.6%) were females. The most frequently reported types of infection were bacteremia, urinary tract infections, intra-abdominal infections, and soft tissue infections, and more than half of them were community-acquired. Comorbidities were common in majority of the patients, and almost half of these were immunosuppressed. K. ascorbata was the most commonly identified species (59.8%), followed by Kluyvera cryocrescens (23.7%), Kluyvera intermedia (3.1%), and Kluyvera georgiana (1.0%). High rates of resistance were recorded for ampicillin (78.1%), 1st-generation cephalosporins (52.1%), and 2nd-generation cephalosporins (43.8%). Third-generation cephalosporins were the most commonly used antibiotics, followed by aminoglycosides. The outcome was favorable for the majority of the patients (89.2%). The mortality rate attributed to the infection was 4.3%.

Early detection of Kluyvera species is critical for effective infection control and antimicrobial stewardship, as these opportunistic pathogens are known to act as reservoirs for antibiotic resistance genes.