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75,693 result(s) for "human pathogen"
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Prevalence of Vibrio spp. in Seafood from German Supermarkets and Fish Markets
This study investigates the prevalence of Vibrio spp. in seafood from supermarkets and fish markets in Berlin, Germany. A total of 306 seafood samples, including shrimp and mussels, were bought from supermarkets between March 2023 and January 2024. Samples were analysed using the ISO standard method and multiplex PCR to identify V. parahaemolyticus, V. alginolyticus, V. cholerae and V. vulnificus. The results indicated an overall Vibrio spp. prevalence of 56%. Among the positive samples, the most prevalent species found was V. parahaemolyticus (58%), followed by V. alginolyticus (42%), V. cholerae non-O1/non-O139 (25%), and V. vulnificus (4%). Samples obtained from supermarkets exhibited a lower prevalence (50%) than those received from fish markets (91%). Virulence genes such as ctxA, tdh, or trh were not detected in the respective Vibrio species. Nevertheless, the high prevalence underscores the need and urgency of continuous seafood surveillance.
Differential interaction of Salmonella enterica serovars with lettuce cultivars and plant-microbe factors influencing the colonization efficiency
The availability of knowledge of the route of infection and critical plant and microbe factors influencing the colonization efficiency of plants by human pathogenic bacteria is essential for the design of preventive strategies to maintain safe food. This research describes the differential interaction of human pathogenic Salmonella enterica with commercially available lettuce cultivars. The prevalence and degree of endophytic colonization of axenically grown lettuce by the S. enterica serovars revealed a significant serovar–cultivar interaction for the degree of colonization (S. enterica CFUs per g leaf), but not for the prevalence. The evaluated S. enterica serovars were each able to colonize soil-grown lettuce epiphytically, but only S. enterica serovar Dublin was able to colonize the plants also endophytically. The number of S. enterica CFU per g of lettuce was negatively correlated to the species richness of the surface sterilized lettuce cultivars. A negative trend was observed for cultivars Cancan and Nelly, but not for cultivar Tamburo. Chemotaxis experiments revealed that S. enterica serovars actively move toward root exudates of lettuce cultivar Tamburo. Subsequent micro-array analysis identified genes of S. enterica serovar Typhimurium that were activated by the root exudates of cultivar Tamburo. A sugar-like carbon source was correlated with chemotaxis, while also pathogenicity-related genes were induced in presence of the root exudates. The latter revealed that S. enterica is conditioned for host cell attachment during chemotaxis by these root exudates. Finally, a tentative route of infection is described that includes plant-microbe factors, herewith enabling further design of preventive strategies.
Pantoea: insights into a highly versatile and diverse genus within the Enterobacteriaceae
The bacterial genus Pantoea comprises many versatile species that have been isolated from a multitude of environments. Pantoea was delineated as a genus approximately 25 years ago, but since then, approximately 20 species have been identified having a diversity of characteristics. Isolates from water and soil have been harnessed for industrial purposes including bioremediation, and the degradation of herbicides and other toxic products. Other isolates possess nitrogen fixation and plant growth-promoting capabilities, which are currently being explored for agricultural applications. Some isolates are antibiotic producers, and have been developed into biocontrol agents for the management of plant diseases. Pantoea is also known to form host associations with a variety of hosts, including plants, insects and humans. Although often thought of as a plant pathogen, recent evidence suggests that Pantoea is being frequently isolated from the nosocomial environment, with considerable debate as to its role in human disease. This review will explore this highly versatile group and its capabilities, its known associations, and the underlying genetic and genomic determinants that drive its diversity and adaptability. This review synthesizes what is currently known about the diverse enterobacterial group, Pantoea, which not only exhibits versatility in both host and non-host environments, but also shows biotechnological promise.
Insights into the temperature responses of Pseudomonas species in beneficial and pathogenic host interactions
Pseudomonas species are metabolically versatile bacteria able to exploit a wide range of ecological niches. Different Pseudomonas species can grow as free-living cells, biofilms, or associated with plants or animals, including humans, and their ecological success partially lies in their ability to grow and adapt to different temperatures. These bacteria are relevant for human activities, due to their clinical importance and their biotechnological potential for different applications such as bioremediation and the production of biopolymers, surfactants, secondary metabolites, and enzymes. In agriculture, some of them can act as plant growth promoters and are thus used as inoculants, whereas others, like P. syringae pathovars, can cause disease in commercial crops. This review aims to provide an overview of the temperature-response mechanisms in Pseudomonas species, looking for novel features or strategies based on techniques such as transcriptomics and proteomics. We focused on temperature-dependent traits mainly associated with virulence, host colonization, survival, and production of secondary metabolites. We analyzed human, animal, and plant pathogens and plant growth-promoting Pseudomonas species, including P. aeruginosa , P. plecoglossicida , several P. syringae pathovars, and P. protegens . Our aim was to provide a comprehensive view of the relevance of temperature-response traits in human and animal health and agricultural applications. Our analysis showed that features relevant to the bacterial-host interaction are adjusted to the environmental or host temperature regardless of the optimal growth temperature in the laboratory, and thus contribute to improving bacterial fitness. Key points • In Pseudomonas species, temperature impacts the bacterial-host interaction. • Interaction traits are expressed at temperatures different from the optimal reported. • The bacterial-host interaction could be affected by climate change.
More than 18,000 effectors in the Legionella genus genome provide multiple, independent combinations for replication in human cells
The genus Legionella comprises 65 species, among which Legionella pneumophila is a human pathogen causing severe pneumonia. To understand the evolution of an environmental to an accidental human pathogen, we have functionally analyzed 80 Legionella genomes spanning 58 species. Uniquely, an immense repository of 18,000 secreted proteins encoding 137 different eukaryotic-like domains and over 200 eukaryotic-like proteins is paired with a highly conserved type IV secretion system (T4SS). Specifically, we show that eukaryotic Rho- and Rab-GTPase domains are found nearly exclusively in eukaryotes and Legionella. Translocation assays for selected Rab-GTPase proteins revealed that they are indeed T4SS secreted substrates. Furthermore, F-box, U-box, and SET domains were present in >70% of all species, suggesting that manipulation of host signal transduction, protein turnover, and chromatin modification pathways are fundamental intracellular replication strategies for legionellae. In contrast, the Sec-7 domain was restricted to L. pneumophila and seven other species, indicating effector repertoire tailoring within different amoebae. Functional screening of 47 species revealed 60% were competent for intracellular replication in THP-1 cells, but interestingly, this phenotype was associated with diverse effector assemblages. These data, combined with evolutionary analysis, indicate that the capacity to infect eukaryotic cells has been acquired independently many times within the genus and that a highly conserved yet versatile T4SS secretes an exceptional number of different proteins shaped by interdomain gene transfer. Furthermore, we revealed the surprising extent to which legionellae have coopted genes and thus cellular functions from their eukaryotic hosts, providing an understanding of how dynamic reshuffling and gene acquisition have led to the emergence of major human pathogens.
Immunotherapies against human bacterial and fungal infectious diseases: A review
Nations’ ongoing struggles with a number of novel and reemerging infectious diseases, including the ongoing global health issue, the SARS-Co-V2 (severe acute respiratory syndrome coronavirus 2) outbreak, serve as proof that infectious diseases constitute a serious threat to the global public health. Moreover, the fatality rate in humans is rising as a result of the development of severe infectious diseases brought about by multiple drug-tolerant pathogenic microorganisms. The widespread use of traditional antimicrobial drugs, immunosuppressive medications, and other related factors led to the establishment of such drug resistant pathogenic microbial species. To overcome the difficulties commonly encountered by current infectious disease management and control processes, like inadequate effectiveness, toxicities, and the evolution of drug tolerance, new treatment solutions are required. Fortunately, immunotherapies already hold great potential for reducing these restrictions while simultaneously expanding the boundaries of healthcare and medicine, as shown by the latest discoveries and the success of drugs including monoclonal antibodies (MAbs), vaccinations, etc. Immunotherapies comprise methods for treating diseases that specifically target or affect the body’s immune system and such immunological procedures/therapies strengthen the host’s defenses to fight those infections. The immunotherapy-based treatments control the host’s innate and adaptive immune responses, which are effective in treating different pathogenic microbial infections. As a result, diverse immunotherapeutic strategies are being researched more and more as alternative treatments for infectious diseases, leading to substantial improvements in our comprehension of the associations between pathogens and host immune system. In this review we will explore different immunotherapies and their usage for the assistance of a broad spectrum of infectious ailments caused by various human bacterial and fungal pathogenic microbes. We will discuss about the recent developments in the therapeutics against the growing human pathogenic microbial diseases and focus on the present and future of using immunotherapies to overcome these diseases. Graphical Abstract The graphical abstract shows the therapeutic potential of different types of immunotherapies like vaccines, monoclonal antibodies-based therapies, etc., against different kinds of human Bacterial and Fungal microbial infections.
Rapid green synthesis of silver nano particles from Ziziphus mauritiana and antibacterial activity against human pathogens
A novel green source Ziziphus mauritiana fresh young leaves was opted to synthesize silver nanoparticles and analyze its antibacterial activity. The bioactive compounds present in the plant extracts reduced silver ions to NPs, indicated by change in color from red to dark brown. In this study, we have successfully synthesized nanoparticles using Z. mauritiana aqueous leaf extract as a reducing agent and the reaction process of synthesized nanoparticles was monitored by UV-Vis spectroscopy. The UV-Vis absorption peak showed maximum adsorption at 420 nm confirmed the silver nanoparticles synthesis. Further characterization was carried out by FTIR and the results recorded a downward shift of absorption the bands between 400 to 4000 cm-1 indicates the formation of silver nanoparticles. Finally, the present research was exploited to study the antibacterial activity of synthesized nanoparticles produced Z. mauritiana was studied using different pathogenic bacteria such as Salmonella sp., Proteus sp., Bacillus sp., Klebsiella pneumonia and E.coli from the well diffusion results, the synthesized silver nanoparticles displayed the best antibacterial property as compared to the antibiotic has been reported in this paper. To the best of our knowledge, this is the first report that the Z. mauritiana aqueous extract facilitate the synthesis of silver nanoparticles and also exhibits antibacterial activity.
The global emergence of a novel Streptococcus suis clade associated with human infections
Streptococcus suis , a ubiquitous bacterial colonizer in pigs, has recently extended host range to humans, leading to a global surge of deadly human infections and three large outbreaks since 1998. To better understand the mechanisms for the emergence of cross‐species transmission and virulence in human, we have sequenced 366 S. suis human and pig isolates from 2005 to 2016 and performed a large‐scale phylogenomic analysis on 1,634 isolates from 14 countries over 36 years. We show the formation of a novel human‐associated clade (HAC) diversified from swine S. suis isolates. Phylogeographic analysis identified Europe as the origin of HAC, coinciding with the exportation of European swine breeds between 1960s and 1970s. HAC is composed of three sub‐lineages and contains several healthy‐pig isolates that display high virulence in experimental infections, suggesting healthy‐pig carriers as a potential source for human infection. New HAC‐specific genes are identified as promising markers for pathogen detection and surveillance. Our discovery of a human‐associated S. suis clade provides insights into the evolution of this emerging human pathogen and extend our understanding of S. suis epidemics worldwide. SYNOPSIS The increasing incidences of human infections caused by Streptococcus suis indicate that this bacterium may undergo adaptive evolution in humans. In this study, a novel clade of S. suis strongly associated with human infections was identified. Large‐scale genomic analysis on clinical strains from human patients and pigs have revealed three distinct bacterial clades, i.e. healthy‐pig clade, disease‐pig clade, and human‐associated clade (HAC). HAC isolates displayed high virulence potential in animal models. Several HAC strains were isolated from healthy‐pigs, suggesting these healthy‐pig carriers might be a potential source for human infection. The origin of HAC was pointed to West Europe, with subsequent spread to other continents, including South America, North America, Africa and Asia. The discriminative markers identified for HAC are useful diagnostic tools for routine surveillance of S. suis in environments and animals, including asymptomatic livestock. Graphical Abstract The increasing incidences of human infections caused by Streptococcus suis indicate that this bacterium may undergo adaptive evolution in humans. In this study, a novel clade of S. suis strongly associated with human infections was identified.
A comparative genomics study of 23 Aspergillus species from section Flavi
Section Flavi encompasses both harmful and beneficial Aspergillus species, such as Aspergillus oryzae, used in food fermentation and enzyme production, and Aspergillus flavus, food spoiler and mycotoxin producer. Here, we sequence 19 genomes spanning section Flavi and compare 31 fungal genomes including 23 Flavi species. We reassess their phylogenetic relationships and show that the closest relative of A. oryzae is not A. flavus, but A. minisclerotigenes or A. aflatoxiformans and identify high genome diversity, especially in sub-telomeric regions. We predict abundant CAZymes (598 per species) and prolific secondary metabolite gene clusters (73 per species) in section Flavi. However, the observed phenotypes (growth characteristics, polysaccharide degradation) do not necessarily correlate with inferences made from the predicted CAZyme content. Our work, including genomic analyses, phenotypic assays, and identification of secondary metabolites, highlights the genetic and metabolic diversity within section Flavi.
Human Pathogen Colonization of Lettuce Dependent Upon Plant Genotype and Defense Response Activation
Fresh produce contaminated with human pathogens may result in foodborne disease outbreaks that cause a significant number of illnesses, hospitalizations, and death episodes affecting both public health and the agribusiness every year. The ability of these pathogens to survive throughout the food production chain is remarkable. Using a genetic approach, we observed that leaf colonization by serovar Typhimurium 14028s ( Typhimurium 14028s) and O157:H7 was significantly affected by genetic diversity of lettuce ( L. and L.). In particular, there was a significant variation among 11 lettuce genotypes in bacterial attachment, internalization, and apoplastic persistence after surface- and syringe-inoculation methods. We observed a significant correlation of the bacterial leaf internalization rate with stomatal pore traits (width and area). Moreover, bacterial apoplastic populations significantly decreased in 9 out of 11 lettuce genotypes after 10 days of surface inoculation. However, after syringe infiltration, populations of O157:H7 and Typhimurium 14028s showed positive, neutral, or negative net growth in a 10-day experimental period among seedlings of different lettuce types. The relative ability of the bacteria to persist in the apoplast of lettuce genotypes after syringe inoculation was minimally altered when assessed during a longer period (20 days) using 3.5- to 4-week-old plants. Interestingly, contrasting bacterial persistence in the lettuce genotypes Red Tide and Lollo Rossa was positively correlated with significant differences in the level of reactive oxygen species burst and callose deposition against Typhimurium 14028s and O157:H7 which are related to plant defense responses. Overall, we characterized the genetic diversity in the interaction between lettuce genotypes and enterobacteria Typhimurium 14028s and O157:H7 and discovered that this genetic diversity is linked to variations in plant immune responses towards these bacteria. These results provide opportunities to capitalize on plant genetics to reduce pathogen contamination of leaves.