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

Abstract

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.

Leclercia adecarboxylata as Emerging Pathogen in Human Infections: Clinical Features and Antimicrobial Susceptibility Testing

“…In our study, a recent exposition to an aquatic environment was identified in one patient (professional swimmer presenting with corneal abscess with keratitis), such as few cases in medical literature [9]. Until now, this bacterium was considered a low-virulence pathogen with uncertain pathogenicity in human infections [6,9,10]. In our 8 samples, L. adecarboxylata was considered as a clinically significant pathogen based on clinical presentations, except for 2 episodes (one patient with VAP and the second with UTI) when clinicians considered it as an asymptomatic carriage or colonization and they have been mistreated.…”

“…L. adecarboxylata is implicated in cases which involve endocarditis [15,16], catheterrelated bacteremia [10,17,18], bacteremia and cellulitis [5,6,9,19,20], urinary tract infections [6,21], pneumonia [5,22] and bacterial peritonitis, especially in peritoneal dialysis patient [7,[11][12][13][14], which was the case for the majority of our clinical presentations. L. adecarboxylata was most often found as a monomicrobial infection in immunocompromised patients, and as part of a polymicrobial infection in immunocompetent patients [5,12].…”

“…In this case series of L. adecarboxylata infections, we highlighted the pathogenicity of this aquatic agent in human pathology since the advancements in microbiology of highresolution methods such as MALDI-TOF MS, which led to accurate identification in early diagnosis and distinction of L. adecarboxylata from Escherichia spp. [5][6][7].…”

“…It can also be isolated from clinical specimens including blood, stool, sputum, urines and wound pus. With new identification methods such as matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), which is preferred for precise species identification over conventional methods, it is currently possible to obtain an accurate identification [5][6][7] of this pathogen. L. adecarboxylata is a 'novel' rare human pathogen, mostly affecting immunocompromised individuals or causing polymicrobial infections in immunocompetent patients.…”

Osteomyelitis and septic arthritis from rare pathogen leclercia adecarboxylata: A case study

“…9 Other literature has shown 91% of isolated pathogens were pan-sensitive to tested antibiotics leaving almost 10% resistant to identified antibiotics. 13 In a laboratory study, they investigated 101 Leclercia strains to 70 antimicrobial agents. They found that L. adecarboxylata was naturally resistant to multiple antibiotics including penicillin G, oxacillin, erythromycin, ketolides, linezolid, and rifampicin.…”