Refine
Document Type
- Article (19)
Language
- English (19)
Has Fulltext
- yes (19)
Is part of the Bibliography
- no (19)
Keywords
- - (16)
- antimicrobial resistance (4)
- virulence (3)
- ESBL- (2)
- One Health (2)
- antibiotic resistance (2)
- biofilm (2)
- next-generation sequencing (2)
- resistance (2)
- wildlife (2)
Institute
Publisher
- MDPI (13)
- Frontiers Media S.A. (3)
- BioMed Central (BMC) (2)
- Wiley (1)
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 problem, as infections have become increasingly difficult to treat. Here, we investigated the occurrence of ESBL-producing E. coli and K. pneumoniae in fecal samples from two black-headed gull colonies breeding on two nature conservation islands in Western Pomerania, Germany. In addition to cloacal samples from adult birds (n = 211) and their nestlings (n = 99) during the 2021 breeding season, collective fecal samples (n = 29) were obtained. All samples were screened for ESBL producers, which were then subjected to whole-genome sequencing. We found a total of 12 ESBL-producing E. coli and K. pneumoniae consisting of 11 E. coli and 1 K. pneumoniae, and including the international high-risk E. coli sequence types (ST)131, ST38, and ST58. Eight of the investigated strains had a MDR genotype and carried a large repertoire of virulence-associated genes, including the pap operon, which is important for urinary tract infections. In addition, we identified many genes associated with adherence, biofilm formation, iron uptake, and toxin production. Finally, our analysis revealed the close phylogenetic relationship of ST38 strains with genomes originating from human sources, underlining their zoonotic and pathogenic character. This study highlights the importance of the One Health approach, and thus the interdependence between human and animal health and their surrounding environment.
Abstract
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 investigate single phytochemicals and combinations, initial microdilution and checkerboard assays were used, followed by time‐kill assays to evaluate the obtained results. The research revealed that phenolic compounds on their own resulted in little or no inhibitory effects. During preliminary tests, most of the combinations resulted in indifference (134 [71.3%]). In all, 30 combinations led to antagonism (15.9%); however, 24 showed synergistic effects (12.8%). The main tests resulted in nine synergistic combinations for the treatment of four different bacteria strains, including two substances (3‐hydroxy‐6‐methoxyflavone, genistein) never tested before in such setup. Time‐kill curves for combinations with possible synergistic effects confirmed the results against Acinetobacter baumannii as the one with the greatest need for research.
Conclusions
The results highlight the potential use of antibiotic–phytocompound combinations for combating infections with multi‐resistant pathogens. Synergistic combinations could downregulate the resistance mechanisms of bacteria.
Significance and Impact of the Study
The aim of this study is to demonstrate the potential use of phenolic natural compounds in combination with conventional antibiotics against multidrug‐resistant bacteria of the ESKAPE group. Due to synergistic effects of natural phenolic compounds combined with antibiotics, pathogens that are already resistant to antibiotics could be resensitized as we were able to reduce their MICs back to sensitive. In addition, combination therapies could prevent the development of resistance by reducing the dose of antibiotics. This approach opens up the basis for future development of antimicrobial therapy strategies, which are so urgently needed in the age of multidrug‐resistant pathogens.
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 for different phenolic natural compounds like epigallocatechin gallate. This study demonstrates this effect for other structurally unrelated phenolics, namely octyl gallate, scutellarein and wedelolactone. To verify whether these structurally different compounds influence identical pathways of biofilm formation in E. coli a broad comparative RNA-sequencing approach was chosen with additional RT-qPCR to gain initial insights into the pathways affected at the transcriptomic level. Bioinformatical analysis of the RNA-Seq data was performed using DESeq2, BioCyc and KEGG Mapper. The comparative bioinformatics analysis on the pathways revealed that, irrespective of their structure, all compounds mainly influenced similar biological processes. These pathways included bacterial motility, chemotaxis, biofilm formation as well as metabolic processes like arginine biosynthesis and tricarboxylic acid cycle. Overall, this work provides the first insights into the potential mechanisms of action of novel phenolic biofilm inhibitors and highlights the complex regulatory processes of biofilm formation in E. coli.
Antimicrobial resistance (AMR) is a serious global health threat with extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales as the most critical ones. Studies on AMR in wild birds imply a possible dissemination function and indicate their potential role as sentinel animals. This study aimed to gain a deeper insight into the AMR burden of wild waterfowl by sampling semi-wild mallard ducks used as sentinels and to identify if AMR bacteria could be recommended to be added to the pathogens of public health risks to be screened for. In total, 376 cloacal and pooled fecal samples were collected from the sentinel plant over a period of two years. Samples were screened for ESBL-carrying E. coli and isolates found further analyzed using antimicrobial susceptibility testing and whole-genome sequencing. Over the sampling period, 4.26% (16/376) of the samples were positive for ESBL-producing E. coli. BlaCTX-M-1 and blaCTX-M-32 were the most abundant CTX-M types. Although none of the top global sequence types (ST) could be detected, poultry-derived ST115 and non-poultry-related STs were found and could be followed over time. The current study revealed low cases of ESBL-producing E. coli in semi-wild mallard ducks, which proves the suitability of sentinel surveillance for AMR detection in water-associated wildlife.
Highly Virulent and Multidrug-Resistant Escherichia coli Sequence Type 58 from a Sausage in Germany
(2022)
Studies have previously described the occurrence of multidrug-resistant (MDR) Escherichia coli in human and veterinary medical settings, livestock, and, to a lesser extent, in the environment and food. While they mostly analyzed foodborne E. coli regarding phenotypic and sometimes genotypic antibiotic resistance and basic phylogenetic classification, we have limited understanding of the in vitro and in vivo virulence characteristics and global phylogenetic contexts of these bacteria. Here, we investigated in-depth an E. coli strain (PBIO3502) isolated from a pork sausage in Germany in 2021. Whole-genome sequence analysis revealed sequence type (ST)58, which has an internationally emerging high-risk clonal lineage. In addition to its MDR phenotype that mostly matched the genotype, PBIO3502 demonstrated pronounced virulence features, including in vitro biofilm formation, siderophore secretion, serum resilience, and in vivo mortality in Galleria mellonella larvae. Along with the genomic analysis indicating close phylogenetic relatedness of our strain with publicly available, clinically relevant representatives of the same ST, these results suggest the zoonotic and pathogenic character of PBIO3502 with the potential to cause infection in humans and animals. Additionally, our study highlights the necessity of the One Health approach while integrating human, animal, and environmental health, as well as the role of meat products and food chains in the putative transmission of MDR pathogens.
Background: Klebsiella pneumoniae causes severe diseases including sepsis, pneumonia
and wound infections and is differentiated into hypervirulent (hvKp) and classic (cKp) pathotypes.
hvKp isolates are characterized clinically by invasive and multiple site infection and phenotypically
in particular through hypermucoviscosity and increased siderophore production, enabled by the
presence of the respective virulence genes, which are partly carried on plasmids. Methods: Here, we
analyzed two K. pneumoniae isolates of a human patient that caused severe multiple site infection.
By applying both genomic and phenotypic experiments and combining basic science with clinical
approaches, we aimed at characterizing the clinical background as well as the two isolates in-depth.
This also included bioinformatics analysis of a chromosomal virulence plasmid integration event.
Results: Our genomic analysis revealed that the two isolates were clonal and belonged to sequence
type 420, which is not only the first description of this K. pneumoniae subtype in Germany but also
suggests belonging to the hvKp pathotype. The latter was supported by the clinical appearance and
our phenotypic findings revealing increased siderophore production and hypermucoviscosity similar
to an archetypical, hypervirulent K. pneumoniae strain. In addition, our in-depth bioinformatics
analysis suggested the insertion of a hypervirulence plasmid in the bacterial chromosome, mediated
by a new IS5 family sub-group IS903 insertion sequence designated ISKpn74. Conclusion: Our study
contributes not only to the understanding of hvKp and the association between hypervirulence and
clinical outcomes but reveals the chromosomal integration of a virulence plasmid, which might lead
to tremendous public health implications.
Multi-drug resistant (MDR), gram-negative Enterobacteriaceae, such as Escherichia coli (E. coli) limit therapeutic options and increase morbidity, mortality, and treatment costs worldwide. They pose a serious burden on healthcare systems, especially in developing countries like Rwanda. Several studies have shown the effects caused by the global spread of extended-spectrum beta-lactamase (ESBL)-producing E. coli. However, limited data is available on transmission dynamics of these pathogens and the mobile elements they carry in the context of clinical and community locations in Sub-Saharan Africa. Here, we examined 120 ESBL-producing E. coli strains from patients hospitalized in the University Teaching Hospital of Butare (Rwanda), their attending caregivers as well as associated community members and livestock. Based on whole-genome analysis, the genetic diversification and phylogenetics were assessed. Moreover, the content of carried plasmids was characterized and investigated for putative transmission among strains, and for their potential role as drivers for the spread of antibiotic resistance. We show that among the 30 different sequence types (ST) detected were the pandemic clonal lineages ST131, ST648 and ST410, which combine high-level antimicrobial resistance with virulence. In addition to the frequently found resistance genes blaCTX–M–15, tet(34), and aph(6)-Id, we identified csg genes, which are required for curli fiber synthesis and thus biofilm formation. Numerous strains harbored multiple virulence-associated genes (VAGs) including pap (P fimbriae adhesion cluster), fim (type I fimbriae) and chu (Chu heme uptake system). Furthermore, we found phylogenetic relationships among strains from patients and their caregivers or related community members and animals, which indicates transmission of pathogens. Also, we demonstrated the presence and potential transfer of identical/similar ESBL-plasmids in different strains from the Rwandan setting and when compared to an external plasmid. This study highlights the circulation of clinically relevant, pathogenic ESBL-producing E. coli among patients, caregivers and the community in Rwanda. Combining antimicrobial resistance with virulence in addition to the putative exchange of mobile genetic elements among bacterial pathogens poses a significant risk around the world.
Multidrug-resistant gram-negative (MRGN) bacteria are a serious threat to global health. We used genomics tostudy MRGN obtained from houseflies in a tertiary Rwandan hospital. Our analysis revealed a high abundance ofdifferent MRGN includingE. colipathogenic lineage ST131 suggesting the important role of flies in disseminatinghighly virulent pathogens in clinical settings and beyond