Leclercia adecarboxylata as an emerging pathogen in human infections: a 13-year retrospective analysis in Southern Hungary.

Introduction: The clinical role of Leclercia adecarboxylata as an opportunistic pathogen in the context of human infections have been highlighted by multiple published case reports, describing these bacteria as novel or emerging pathogens. Methodology: The study included L. adecarboxylata isolates and laboratory data collected, corresponding to a 13-year time period (between 1 January 2005 and 31 December 2017). Presumptively identified L. adecarboxylata isolates were re-identified using VITEK 2 Compact ID/AST and MALDI-TOF MS analysis. Results: n = 34 isolates were verified by VITEK 2 system and MALDI-TOF. The fosfomycin-agar and CPS Elite agar were effective in the phenotypic differentiation of the isolates. N = 18 (52.9%) of L. adecarboxylata was considered as clinically significant pathogens (based on the clinical signs and symptoms), while n = 16 (47.1%) were considered as contaminants. These pathogens were isolated from wound/abscess samples (n = 9), urine samples (n = 6) and blood cultures (n = 3). 31 out of 34 isolates (91.2%) were pan-sensitive (i.e. wild type) to the tested antibiotics. The median age of affected patients was 57 years (range: 12-80 years), 11 out of 18 patients (61.1%) presented with underlying immunosuppression at the time of isolation. Conclusions: Based on the finding of this study, the actual (published) frequency of L. adecarboxylata infections needs to be re-evaluated as the risk of misidentification (and reporting the isolate as a pan-sensitive Escherichia coli) is high. Additional reporting of cases, both from a microbiological and clinical standpoint, could help clinicians develop a better understanding of the potential of this organism as a pathogen.