Leuconostoc as an emerging pathogen in humans: an updated systematic review.

BACKGROUND: Leuconostoc belongs to the Lactobacillaceae family and is often mistaken for Enterococcus or Streptococcus. This pathogen is commonly found on plants and vegetables and in dairy products and wine. However, Leuconostoc has recently been recognized as an emerging human pathogen that can cause many types of infections. AIM: The purpose of this study was to systematically review all published literature on Leuconostoc infections and describe the epidemiological and microbiological characteristics, antimicrobial susceptibility, treatments and outcomes of infections in humans. METHODS: A systematic review of the literature on Leuconostoc published in the PubMed, Embase, Web of Science, and China National Knowledge Infrastructure (CNKI) databases (as of March 18, 2024) was conducted to obtain epidemiological, clinical, microbiological, therapeutic and outcome data for Leuconostoc infections. FINDINGS: A total of 86 studies involving 126 patients were included in the final analysis. The most common Leuconostoc infections were bloodstream infections, intracranial infections, and infective endocarditis. Comorbidities (neoplasms and gastrointestinal disorders), the use of antibiotics (especially vancomycin), the use of indwelling central venous catheters, and the use of parenteral nutrition were very common among patients. Genetic sequencing and broth microdilution or agar dilution methods were the most reliable methods for the identification of Leuconostoc and antimicrobial susceptibility testing, respectively. Leuconostoc lactis was the most common species identified in clinical practice. The most common treatment regimen was penicillin alone or in combination with aminoglycosides. CONCLUSIONS: The epidemiological characteristics, clinical features, microbiological characteristics, treatments, and outcomes of all published cases of Leuconostoc infection were reviewed in this study, and the findings will contribute to early clinical recognition of infections with this bacterium and improved treatment efficacy.