Sebastian Guenther

Universität Greifswald · Institute of Pharmacy

Clinically relevant ESBL-producing multi-resistant Escherichia coli have been on the rise for years. Initially restricted to mostly a clinical context, recent findings prove their prevalence in extra-clinical settings independent of the original occurrence of antimicrobial resistance in the environment. To get further insights into the complex ecol...

The use of whole-genome phylogenetic analysis has revolutionized our understanding of the evolution and spread of many important bacterial pathogens due to the high resolution view it provides. However, the majority of such analyses do not consider the potential role of accessory genes when inferring evolutionary trajectories. Moreover, the recentl...

Multidrug-resistant gram-negative pathogens such as Escherichia coli have become increasingly difficult to treat and therefore alternative treatment options are needed. Targeting virulence factors like biofilm formation could be one such option. Inhibition of biofilm-related structures like curli and cellulose formation in E. coli has been shown fo...

Species of the genus Drosera, known for carnivorous plants, such as sundew, have been traditionally used for centuries as medicinal plants. Efficacy-determining compounds are naphthoquinones and flavonoids. Flavonoids possess a broad spectrum of bioactive properties, including biofilm inhibitory activity. Biofilms render antibiotics ineffective, co...

Screening for biofilm inhibition by purified natural compounds is difficult due to compounds’ chemical diversity and limited commercial availability, combined with time- and cost-intensiveness of the laboratory process. In silico prediction of chemical and biological properties of molecules is a widely used technique when experimental data availabi...

The methanolic extract of the leaves of Acacia nilotica ssp. kraussiana showed inhibition of multidrug resistant E. coli biofilm in a concentration of 50 µg/mL. The 20% and 30% methanol SPE fractions were the most potent fractions, and they inhibited E. coli biofilm formation in a concentration of 25 µg/mL. Five compounds were isolated from the 20%...

The global spread of multidrug-resistant Escherichia coli threatens human, animal, and environmental health. Despite the recognition of water bodies as potential reservoirs, research on antimicrobial resistance (AMR) and antibiotic residues in the Baltic Sea is limited. In this study, we examined the presence of ESBL-producing E. coli in surface wa...

Background Convergence of Klebsiella pneumoniae (KP) pathotypes has been increasingly reported in recent years. These pathogens combine features of both multidrug-resistant and hypervirulent KP. However, clinically used indicators for hypervirulent KP identification, such as hypermucoviscosity, appear to be differentially expressed in convergent KP...

The global spread of multidrug-resistant Escherichia coli threatens human, animal, and environmental health. Despite the recognition of water bodies as potential reservoirs, research on AMR in the Baltic Sea is limited. In this study, we examined the presence of ESBL-producing E. coli in surface water in northeastern Germany. We then conducted phen...

Epidermal melanin synthesis determines an individual’s skin color. In humans, melanin is formed by melanocytes within the epidermis. The process of melanin synthesis strongly depends on a range of cellular factors, including the fine-tuned interplay with reactive oxygen species (ROS). In this context, a role of cold atmospheric plasma (CAP) on mela...

Biofilms of pathogenic bacteria are responsible for persistent infections in humans, therefore investigations of biofilm formation and treatment strategies are required. The gram‐negative enterobacterium Escherichia (E.) coli is the most common pathogen causing chronic or recurring urinary tract infections. Metabolomics approaches targeted the bact...

Hypermucoviscosity in Klebsiella pneumoniae is often related to the overexpression of capsular polysaccharides, regulated by complex biosynthetic mechanisms in response to external cues. However, little is known about the processes involved in hypermucoviscosity in convergent K. pneumoniae , which combine extensive drug resistance with high bacteri...

Background: Klebsiella pneumoniae (KP), often multidrug-resistant (MDR), is a significant public health concern and frequently associated with various diseases including urinary-tract infection. In addition, in recent years, an increasing number of studies reports on the emergence of convergent KP that combine MDR with hypervirulence leading to sev...

Ethiopians have deep‐rooted traditions of using plants to treat ailments affecting humans and domesticated animals. Approximately 80% of the population continues to rely on traditional medicine, including for the prevention and treatment of viral diseases. Many antiviral plants are available to and widely used by communities in areas where access t...

Introduction Horse clinics are hotspots for the accumulation and spread of clinically relevant and zoonotic multidrug-resistant bacteria, including extended-spectrum β-lactamase producing (ESBL) Enterobacterales. Although median laparotomy in cases of acute equine colic is a frequently performed surgical intervention, knowledge about the effects of...

Urbanization, industrialization, and intensification of agriculture have led to considerable heavy metal pollution across the globe, harming our ecosystems. Concentrations of arsenic (As), cadmium (Cd), copper (Cu), and lead (Pb) have been analysed in 249 eggshells collected between 2006 and 2021 from 83 female Common Cranes ( Grus grus ) nesting w...

Purpose: Identification of new biofilm inhibiting compounds through ethnopharmacological investigation and testing their synergistic potential with antibiotics to exploit new therapeutic options in the treatment of infections with multiresistant E. coli. Methods: In this study, we investigated 22 medicinal plants, which have been traditionally use...

Monographs of the European Pharmacopoeia (Ph. Eur.) are the basis for quality control of medicinal plants and therefore important to ensure the consistency, quality, safety, and efficacy of phytopharmaceuticals. The traditional medicinal plant sundew ( Drosera sp.) has disappeared from therapy due to nature conservation, but can now be cultivated s...

Land use change, mainly in terms of intensification of agriculture, urbanization, and industrialization has led to considerable pollution across the globe. Heavy metals are considered as major pollutants harming our ecosystems. Besides top level predators, long-living, omnivorous species, like Common cranes (Grus grus) are considered particularly v...

Traditionelle Arzneipflanzen werden oft zur Behandlung von Infektionskrankheiten eingesetzt und sind in vielen Ländern des globalen Südens, insbesondere in Simbabwe, noch heute einige der am häufigsten sowie kostengünstigsten eingesetzten Arzneien [1]. In dieser Studie wurden 22 traditionell bei Infektionskrankheiten eingesetzte Pflanzenextrakte au...

Horse clinics are hotspots for the accumulation and spread of clinically relevant and zoonotic multidrug-resistant bacteria, including extended-spectrum β-lactamase producing (ESBL) Enterobacterales. Although median laparotomy in cases of acute equine colic is a frequently performed surgical intervention, knowledge about the effects of peri-operati...

The goal of this study was to assess the anticancer efficacy of chlorojanerin against various cancer cells. The effects of chlorojanerin on cell cytotoxicity, cell cycle arrest, and cell apoptosis were examined using MTT assay, propidium iodide staining, and FITC Annexin V assay. RT-PCR was employed to determine the expression levels of apoptosis-r...

Background: Klebsiella pneumoniae, which is frequently associated with hospital- and community-acquired infections, contains multidrug-resistant (MDR), hypervirulent (hv), non-MDR/non-hv as well as convergent representatives. It is known that mostly international high-risk clonal lineages including sequence types (ST) 11, 147, 258, and 307 drive th...

Simple Summary Among its role within the commensal bacterial flora, Escherichia coli (E. coli) is known as a cause of intestinal or extraintestinal diseases in pets and their owners. In order to reveal factors associated with the carriage of extended spectrum beta-lactamase-producing Escherichia coli in dogs, rectal swabs from 1000 dogs visiting a...

Introduction and objective: Candidiasis is a fungal infection caused by yeasts from the Ogenus Candida. Considering increasing antifungal resistance rates the activity was analyzed of natural compounds to eradicate Candida spp. The aim of the study was to check the antifungal activity of selected essential oil compounds (EOCs; thymol, menthol, euge...

Investigation of the antibacterial activity of ammonium hexafluorosilicates against one of the main oral pathogens that causes caries - Streptococcus mutans.

Multidrug-resistant (MDR) Enterobacterales, including extended-spectrum β‑lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae, not only emerge in healthcare settings but also in other habitats, such as livestock and wildlife. The spread of these pathogens, which often combine resistance with high-level virulence, is a growing prob...

Combination therapy is used to retard the selection of malaria parasite strains resistant to individual components of a combination of drugs. This approach has proved to be a success in the combination of sulphadoxine and pyrimethamine, which targets two different steps in the folate pathway of malaria parasites. However, after the success of this...

The study aimed to examine the influence of a rotating magnetic field (RMF) of two different frequencies (5 and 50 Hz) on the expression of regulatory (agrA, hld, rot) and staphylococcal enterotoxin (SE—sea, sec, sel) genes as well as the production of SEs (SEA, SEC, SEL) by the Staphylococcus aureus FRI913 strain cultured on a medium supplemented...

The aim of the study was to evaluate the clonal relatedness and antimicrobial susceptibility in 52 Staphylococcus aureus strains isolated from cut wound infections in non-related community patients and to determine the presence of selected virulence genes. To analyse the clonal relatedness of investigated strains, pulsed-field gel electrophoresis (...

The ability of extensively drug-resistant (XDR) Klebsiella pneumoniae to rapidly acquire resistance to novel antibiotics is a global concern. Moreover, Klebsiella clonal lineages that successfully combine resistance and hypervirulence have increasingly occurred during the last years. However, the underlying mechanisms of counteracting fitness costs...

In the search for alternative treatment options for infections with multi-resistant germs, traditionally used medicinal plants are currently being examined more intensively. In this study, the antimicrobial and anti-biofilm activities of 14 herbal drugs were investigated. Nine of the tested drugs were traditionally used in Europe for treatment of l...

This communication introduces the first-time application of high-resolution continuum-source molecular absorption spectrometry (HR CS MAS) for the quantification of a peptide. The graphite furnace technique was employed and the tripeptide glutathione (GSH) served as a model compound. Based on measuring sulfur in terms of carbon monosulfide (CS), a...

Almost one-third of all proteins require metal ions as an essential component in key biological processes and approximately half of all enzymes are associated with one or more metal ions. The naturally occurring selenium is very toxic at higher levels, but few bacteria can reduce it into the less toxic insoluble elemental selenium. Selenium is requ...

Aim: To verify synergistic effects we investigated the antimicrobial activity of seven phenolic phytochemicals (gallic acid; epicatechin; epigallocatechin gallate; daidzein; genistein; myricetin; 3-hydroxy-6-methoxyflavone) in combination with six antibiotics against multidrug-resistant isolates from the ESKAPE group. Methods and results: To inv...

Medicinal plants have been traditionally used to treat cancer in Ethiopia. However, very few studies have reported the in vitro anticancer activities of medicinal plants that are collected from different agro-ecological zones of Ethiopia. Hence, the main aim of this study was to screen the cytotoxic activities of 80% methanol extracts of 22 plants...

Beta glucans are complex glucose polymers well known for their immune modulatory properties. Therefore they are used and advertised in dietary supplements. Unfortunately there is no standardized test system for quality control of such health-related foods. This approach combined wet chemical and enzyme-based quantification methods (e.g. aniline blu...

Minimal inhibitory concentration-based pharmacokinetic/pharmacodynamic (PK/PD) indices are commonly applied to antibiotic dosing optimisation, but their informative value is limited, as they do not account for bacterial growth dynamics over time. We aimed to comprehensively characterise the exposure–effect relationship of levofloxacin against Esche...

Previous research identified veterinary clinics as hotspots with respect to accumulation and spread of multidrug resistant extended-spectrum β-lactamase(ESBL)-producing Escherichia coli (EC). Therefore, promoting the prudent use of antibiotics to decrease selective pressure in that particular clinical environment is preferable to enhance biosecurit...

To increase our understanding of bacterial intestinal colonization in animal populations lacking substantial anthropogenic influence we studied the diversity of E. coli in cormorants from the pristine West-Mongolian steppe. E. coli were isolated from individual birds of two cormorant colonies located on small islands in lakes at least 100 km away f...

The colonization of broilers with extended-spectrum β-lactamase- (ESBL-) and plasmid-mediated AmpC β-lactamase- (pAmpC-) producing Enterobacteriaceae has been extensively studied. However, only limited data on intervention strategies to reduce the colonization throughout the fattening period are available. To investigate practically relevant manage...

Background Antibiotic-resistant Klebsiella pneumoniae are a major cause of hospital- and community-acquired infections, including sepsis, liver abscess, and pneumonia, driven mainly by the emergence of successful high-risk clonal lineages. The K. pneumoniae sequence type (ST) 307 lineage has appeared in several different parts of the world after fi...

Strain CS-1 T , a novel facultative anaerobic bacterium, was isolated from the larval gastrointestinal tract of the biting midge, Culicoides sonorensis , a vector of the epizootic haemorrhagic disease virus and the bluetongue virus. Cells were Gram-stain-positive, non-motile, non-spore-forming, pleomorphic rods. Optimal growth occurred at pH 7.5 an...

In vitro antiproliferative activities of the 80% methanol extracts of 21 traditionally used Ethiopian medicinal plants were studied using human acute myeloid leukemia (MV4-11) cell line. Among the tested plants, Euphorbia schimperiana Scheele and Gnidia involucrata Steud. ex A. Rich. exhibited significant antiproliferative activity with GI50 values...

Background In addition to the broad dissemination of pathogenic extended-spectrum beta-lactamase (ESBL)-producing Escherichia (E.) coli in human and veterinary medicine and the community, their occurrence in wildlife and the environment is a growing concern. Wild birds in particular often carry clinically relevant ESBL-producing E. coli. Objective...

Airborne bacteria are a general problem in medical or health care facilities with a high risk for nosocomial infections. Rooms with a continuous airflow, such as operation theaters, are of particular importance due to a possible dissemination and circulation of pathogens including multidrug‐resistant microorganisms. In this regard, a cold atmospher...

Escherichia coli colonization and infection results in formation of adhesion patterns which in turn contribute to pathotyping of intestinal E. coli. The adhesion patterns of 282 E. coli isolates on different cell lines were determined to establish various adhesion patterns such as diffusely distributed, microcolonies, chains and clumps. Only two st...

Background: Following the ban on antimicrobial usage for growth promotion in animal husbandry in the EU, non-antimicrobial agents including heavy metal ions (e.g. zinc and copper), prebiotics or probiotics have been suggested as alternatives. Zinc has extensively been used in pig farming, particularly during weaning of piglets to improve animal he...

Understanding the complex interactions of microbial communities including bacteria, archaea, parasites, viruses and fungi of the gastrointestinal tract (GIT) associated with states of either health or disease is still an expanding research field in both, human and veterinary medicine. GIT disorders and their consequences are among the most importan...

Extended-spectrum beta-lactamase- (ESBL-) and AmpC beta-lactamase- (AmpC-) producing Enterobacteriaceae pose a risk for both human and animal health. For livestock, highest prevalences have been reported in broiler chickens, which are therefore considered as a reservoir of multidrug-resistant bacteria. The possibility of transfer to humans either b...

The efficient multifunctionalization by one‐pot or cascade catalytic systems has developed as an important research field, but is often challenging due to incompatibilities or cross‐reactivities of the catalysts leading to side product formation. Herein we report the stereoselective preparation of cis‐ and trans‐4‐aminocyclohexanol from the potenti...

Imine reductases (IREDs) allow the one‐step preparation of optically active secondary and tertiary amines by reductive amination of ketones. Until now, mainly α‐chiral amines have been prepared by this route. In this study, we explored the possibility of synthesizing β‐chiral amines, a class of compounds which is also frequently found as structural...

Objective: To determine the prevalence and genetic relatedness of blaCTX-M-type extended spectrum-β-lactamase (ESBL)-producing Escherichia coli at the human-animal interface in Pakistan. Materials and Methods: A total of 150 human, cattle, and poultry fecal samples (50 each) were screened for ESBL-producing E. coli using ESBL CHROMagar®. Bacterial...

Carbapenems are considered one of few remaining treatment options against multidrug-resistant Gram-negative pathogens in human clinical settings. The occurrence of carbapenemase-producing Enterobacteriaceae in livestock and food is a major public health concern. Particularly the occurrence of VIM-1-producing Salmonella Infantis in livestock farms i...

The pathogenic ESBL-producing E. coli lineage ST648 is increasingly reported from multiple origins. Our study of a large and global ST648 collection from multiple hosts (87 whole-genome sequences) combining core and accessory genomics with functional analyses and in vivo experiments suggests that ST648 is a nascent and generalist lineage, lacking c...

[This corrects the article DOI: 10.3389/fcimb.2018.00271.].

ESBL-producing Klebsiella pneumoniae (K. pneumoniae) represent an increasing problem both in human and veterinary medicine. As SHV-2 - encoding K. pneumoniae were recently detected in the broiler production we were interested in investigating a possible transmission along the broiler production chain and furthermore, in evaluating their possible im...

Highlights • Cross-contamination with ESBL-producing potential pathogenic strains was shown by WGS. • Chicken meat from originally ESBL-free broilers became contaminated in the slaughterhouse. • Scalding and defeathering were critical contamination steps during carcass processing. Abstract Extended-spectrum beta-lactamase- (ESBL-) producing Kleb...

Ascariasis is a widespread soil-transmitted helminth infection caused by the intestinal roundworm Ascaris lumbricoides in humans, and the closely related Ascaris suum in pigs. Progress has been made in understanding interactions between helminths and host immune cells, but less is known concerning the interactions of parasitic nematodes and the hos...

Background Extended spectrum beta lactamase (ESBL)-producing extraintestinal pathogenic Escherichia coli infections are of global interest because of their clinical and economic impact. The ESBL resistance genes disseminate through plasmids, and are found in successful global lineages such as ST131 and ST648. The carriage of plasmids has been sugge...