Resistance phenotype and virulence potential of Leclercia adecarboxylata strains isolated from different sources

Introduction. Leclercia adecarboxylata is a member of Enterobacterales, often considered an opportunistic pathogen. Recent reports have highlighted L. adecarboxylata as an emerging pathogen harbouring virulence and resistance determinants.Gap statement. Little information exists on virulence and resistance determinants in L. adecarboxylata strains isolated from environmental, food, and clinical samples.Aim. To determine the presence of resistance and virulence determinants and plasmid features in L. adecarboxylata strains isolated from environmental, food, and clinical samples, as well as their phylogenetic relationship.Results. All strains tested showed resistance to β-lactams and quinolones but were sensitive to aminoglycosides and nitrofurans. However, even though fosfomycin resistance is considered a characteristic trait of L. adecarboxylata, the resistance phenotype was only observed in 50 % of the strains; bla TEM was the most prevalent BLEE gene (70 %), while the quinolone qnrB gene was observed in 60 % of the strains. Virulence genes were differentially observed in the strains, with adhesion-related genes being the most abundant, followed by toxin genes. Finally, all strains carried one to seven plasmid bands ranging from 7 to 125 kbps and harboured several plasmid addiction systems, such as ParDE, VagCD, and CcdAB in 80 % of the strains.Conclusions. L. adecarboxylata is an important emerging pathogen that may harbour resistance and virulence genes. Additionally, it has mobilizable genetic elements that may contribute to the dissemination of genetic determinants to other bacterial genera.

Cross-Over Pathogenic Bacteria Detected in Infected Tomatoes (Solanum lycopersicum L.) and Peppers (Capsicum annuum L.) in Bulgaria

The ability of certain human pathogens to adapt to plants without losing their virulence toward people is a major concern today. Thus, the aim of the present work was the investigation of the presence of cross-over pathogenic bacteria in infected tomato and pepper plants. The objects of the study were 21 samples from seven different parts of the plants and three from tomato rhizosphere. In total, 26 strains were isolated, identified by MALDI-TOF, and phenotypically characterized. The PCR amplification of the rpoB gene was applied as an approach for the rapid detection of cross-over pathogens in plant samples. A great bacterial diversity was revealed from tomato samples as nine species were identified (Leclercia adecarboxylata, Pseudesherichia vulneris, Enterobacter cancerogenus, Enterobacter cloacae, Enterobacter bugandensis, Acinetobacter calcoaceticus, Pantoea agglomerans, Pantoea ananatis, and Pectobacterium carotovorum). Polymicrobial contaminations were observed in samples T2 (tomato flower) and T10 (tomato fruit). Five species were identified from pepper samples (P. agglomerans, L. adecarboxylata, Pseudomonas sp., Pseudomonas putida, and Enterococcus sp.). Antibiotic resistance patterns were assigned in accordance with EFSA recommendations. All isolates showed varying resistance to the tested antibiotics. The genetic basis for the phenotypic antibiotic resistance was not revealed. No genes for the virulence factors were found among the population. To our knowledge, this is the first overall investigation of tomato and pepper cross-over pathogenic bacterial populations in Bulgaria.

Leclercia adecarboxylata infective endocarditis in a man with mitral stenosis: A case report and review of the literature

BACKGROUND

Infective endocarditis (IE) is a rare disease with a high mortality rate. Leclercia adecarboxylata (L. adecarboxylata) is a movable Gram-negative bacillus of enterobacteriaceae, and it can rarely be a pathogen which often affects immunodeficient patients. There are about three cases of immunocompetent patients with monomicrobial L. adecarboxylata infection. There are only three reported cases of IE caused by L. adecarboxylata in the world. The mitral valve is often affected in IE, and the prognosis for IE with mitral valve lesions is often poor.

CASE SUMMARY

A 51-year-old man was found to have moderate to severe mitral stenosis on echocardiography. He came to our Cardiothoracic Surgery Department for surgical management. A diastolic murmur was heard on auscultation of the heart in the mitral region. On the second day of hospitalisation, he presented with slurred speech, reduced muscle strength in the left limb, and acute cerebral infarction on cranial computed tomography. Surgical treatment was decided to postpone. On the ninth day of admission, the patient developed a sudden high fever and shock and was transferred to the Cardiac Intensive Care Unit, where echocardiogram revealed an anterior mitral valve leaflet vegetation. After empirical anti-infective treatment with vancomycin (1g q12h), an emergency valve replacement was performed. Bacterial culture identified L. adecarboxylata. Anti-infective treatment with piperacillin-tazobactam (4.5g q8h) was added for 4 wk. Follow-up echocardiography showed normal bioprosthetic valve function after mitral valve replacement.

CONCLUSION

We report the first case of L. adecarboxylata IE in China, and clinicians should pay attention to this pathogen.

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

(1) Background: Leclercia adecarboxylata (L. adecarboxylata) is a gram-negative bacillus of the Enterobacteriaceae family, which is uncommonly isolated from clinical specimens. L. adecarboxylata is considered as an aquatic opportunistic pathogen and most of the human infections are polymicrobial and usually occur in immunocompromised hosts. (2) Methods: In this retrospective study, we included all L. adecarboxylata strains since the introduction of MALDI-TOF MS in the Microbiology Department of Nord Franche-Comté Hospital, France (from 1 March 2015 to 31 July 2019). We studied demographic characteristics, comorbidities, characteristics of the current infection and outcome as well as antimicrobial susceptibility testing in all isolates. (3) Results: A total of 8 samples were identified (in 6 patients (4M/2F), with a recurrent L. adecarboxylata infection in 2 patients). The patients’ mean age was 66.2 years (range: 19–84). All patients were considered as immunocompetent, except a peritoneal dialysis patient with kidney transplantation. An exposition to an aquatic environment was identified in one patient. The most prevalent clinical feature was catheter-associated male urinary tract infection (in 3 cases) followed by ventilator-associated pneumonia (in 2 cases). One of 6 patients presented L. adecarboxylata bacteremia. L. adecarboxylata was part of a polymicrobial infection in 4 patients. The isolates showed a high susceptibility to all tested antibiotics, except one strain, which was resistant to fosfomycin. All patients with L. adecarboxylata infection were treated with antibiotics with a favorable outcome. (4) Conclusion: This study confirms the pathogenicity of L. adecarboxylata, even in immunocompetent patients, with a high susceptibility to antibiotics.