Leuconostoc mesenteroides periprosthetic knee infection, an unusual fastidious Gram-positive bacteria: a case report

Conjugates of Chloramphenicol Amine and Berberine as Antimicrobial Agents

In order to obtain antimicrobial compounds with improved properties, new conjugates comprising two different biologically active agents within a single chimeric molecule based on chloramphenicol (CHL) and a hydrophobic cation were synthesized and studied. Chloramphenicol amine (CAM), derived from the ribosome-targeting antibiotic CHL, and the plant isoquinoline alkaloid berberine (BER) are connected by alkyl linkers of different lengths in structures of these conjugates. Using competition binding, double reporter system, and toeprinting assays, we showed that synthesized CAM-Cn-BER compounds bound to the bacterial ribosome and inhibited protein synthesis like the parent CHL. The mechanism of action of CAM-C5-BER and CAM-C8-BER on the process of bacterial translations was similar to CHL. Experiments with bacteria demonstrated that CAM-Cn-BERs suppressed the growth of laboratory strains of CHL and macrolides-resistant bacteria. CAM-C8-BER acted against mycobacteria and more selectively inhibited the growth of Gram-positive bacteria than the parent CHL and the berberine derivative lacking the CAM moiety (CH₃-C8-BER). Using a potential-sensitive fluorescent probe, we found that CAM-C8-BER significantly reduced the membrane potential in B. subtilis cells. Crystal violet assays were used to demonstrate the absence of induction of biofilm formation under the action of CAM-C8-BER on E. coli bacteria. Thus, we showed that CAM-C8-BER could act both on the ribosome and on the cell membrane of bacteria, with the alkylated berberine fragment of the compound making a significant contribution to the inhibitory effect on bacterial growth. Moreover, we showed that CAM-Cn-BERs did not inhibit eukaryotic translation in vitro and were non-toxic for eukaryotic cells.

Leuconostoc, a masquerading pathogen in oral cancer patient: A rare case report

Osteoradionecrosis is the most common cause of mandibular osteomyelitis. Here we are reporting a case of osteomyelitis of the mandible caused by Leuconostoc mesenteroides spp cremoris. The frequency of Leuconostoc infections are under reported mainly due to its difficult identification. Non pathogenic organism like leuconostoc can cause infection in the immunocompromised and should warrant proper microbial identification and adequate targeted treatment to manage the patients.

Multilocus Sequence Typing of Leuconostoc mesenteroides Strains From the Qinghai-Tibet Plateau

Leuconostoc mesenteroides strains were a type of epiphytic bacterium widely used in fermented foods and products in the biochemical and pharmaceutical industries but data on its presence in foods from Qinghai-Tibet Plateau in China was scarce. In this study, molecular analysis based on multilocus sequence typing (MLST) with eight housekeeping genes (pyrG, groeL, rpoB, recA, uvrC, murC, carB, and pheS) was carried out on 45 L. mesenteroides strains isolated from different plants and dairy products from Qinghai-Tibet Plateau in China. The objective of this study was to perform genetic diversity analysis and explore the relationship between strains and isolate samples or separate regions. A total of 25 sequence types (STs) were identified with a diversity of up to 55.6%, which were grouped into one clonal complexes (CCs), 3 doublets and 17 singletons by eBURST. The results of minimum spanning tree and clustering analysis indicated these L. mesenteroides strains from the Qinghai-Tibet Plateau were relatively weakly related to the isolated region. However, there was a close relationship between the genotypes of L. mesenteroides strains and the type of the isolated sample, which was consistent with the results of API 50CH. The MLST scheme presented in this study provides a shareable and comparable sequence database and enhances our knowledge of the population diversity of L. mesenteroides strains which will be further used for the selection of industrial strains.

Scientific Opinion on the update of the list of QPS-recommended biological agents intentionally added to food or feed as notified to EFSA (2017-2019)

The qualified presumption of safety (QPS) was developed to provide a safety pre-assessment within EFSA for microorganisms. Strains belonging to QPS taxonomic units (TUs) still require an assessment based on a specific data package, but QPS status facilitates fast track evaluation. QPS TUs are unambiguously defined biological agents assessed for the body of knowledge, their safety and their end use. Safety concerns are, where possible, to be confirmed at strain or product level, and reflected as 'qualifications'. Qualifications need to be evaluated at strain level by the respective EFSA units. The lowest QPS TU is the species level for bacteria, yeasts and protists/algae, and the family for viruses. The QPS concept is also applicable to genetically modified microorganisms used for production purposes if the recipient strain qualifies for the QPS status, and if the genetic modification does not indicate a concern. Based on the actual body of knowledge and/or an ambiguous taxonomic position, the following TUs were excluded from the QPS assessment: filamentous fungi, oomycetes, streptomycetes, Enterococcus faecium, Escherichia coli and bacteriophages. The list of QPS-recommended biological agents was reviewed and updated in the current opinion and therefore now becomes the valid list. For this update, reports on the safety of previously assessed microorganisms, including bacteria, yeasts and viruses (the latter only when used for plant protection purposes) were reviewed, following an Extensive Literature Search strategy. All TUs previously recommended for 2016 QPS list had their status reconfirmed as well as their qualifications. The TUs related to the new notifications received since the 2016 QPS opinion was periodically evaluated for QPS status in the Statements of the BIOHAZ Panel, and the QPS list was also periodically updated. In total, 14 new TUs received a QPS status between 2017 and 2019: three yeasts, eight bacteria and three algae/protists.

Update of the list of QPS-recommended biological agents intentionally added to food or feed as notified to EFSA 7: suitability of taxonomic units notified to EFSA until September 2017

The qualified presumption of safety (QPS) concept was developed to provide a harmonised generic pre-evaluation to support safety risk assessments of biological agents performed by EFSA's scientific Panels. The identity, body of knowledge, safety concerns and antimicrobial resistance of valid taxonomic units were assessed. Safety concerns identified for a taxonomic unit are, where possible and reasonable in number, considered to be 'qualifications' which should be assessed at the strain level by the EFSA's scientific Panels. No new information was found that would change the previously recommended QPS taxonomic units and their qualifications. The BIOHAZ Panel confirms that the QPS approach can be extended to a genetically modified production strain if the recipient strain qualifies for the QPS status, and if the genetic modification does not indicate a concern. Between April and September 2017, the QPS notification list was updated with 46 applications for market authorisation. From these, 14 biological agents already had QPS status and 16 were not included as they are filamentous fungi or enterococci. One notification of Streptomyces K-61 (notified as former S. griseoviridis) and four of Escherichia coli were not considered for the assessment as they belong to taxonomic units that were excluded from further evaluations within the current QPS mandate. Eight notifications of Bacillus thuringiensis and one of an oomycete are pending the reception of the complete application. Two taxonomic units were evaluated: Kitasatospora paracochleata, which had not been evaluated before, and Komagataella phaffii, previously notified as Pichia pastoris included due to a change in the taxonomic identity. Kitasatospora paracochleata cannot be granted QPS status due to lack of information on its biology and to its possible production of toxic secondary metabolites. The species Komagataella phaffii can be recommended for the QPS list when used for enzyme production.

Acute Endophthalmitis Caused by Leuconostoc spp. following Intravitreal Bevacizumab Injection

We present a case of acute endophthalmitis caused by <i>Leuconostoc</i> spp. following intravitreal bevacizumab injection. An 86-year-old immunocompetent female developed acute endophthalmitis after intravitreal injection of bevacizumab for neovascular age-related macular degeneration. The patient presented with pain, visual acuity of hand motions, hypopyon, and dense vitritis 96 h after treatment. She was treated with vitreous and anterior chamber tap followed by intravitreal injections of 1 mg vancomycin, 2.25 mg ceftazidime, and 400 μg dexamethasone. Cultures revealed growth of <i>Leuconostoc</i> spp., a genus of gram-positive bacteria that is inherently resistant to vancomycin. Due to persistent inflammation, pars plana vitrectomy (PPV) with intravitreal injection of 0.4 mg amikacin was performed 16 days later, followed by resolution of endophthalmitis and return of vision to 20/40. In conclusion, the management of acute endophthalmitis caused by <i>Leuconostoc</i> spp., a gram-positive coccobacillus, can be particularly challenging due to its inherent resistance to vancomycin. PPV with intravitreal amikacin led to resolution of endophthalmitis. Our case expands the number of cases of endophthalmitis caused by <i>Leuconostoc</i> spp. and highlights the possibility of <i>Leuconostoc</i>-related endophthalmitis in an outpatient setting in an immunocompetent host.