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International Journal of Environmental... Aug 2020is an important gram-negative opportunistic pathogen that causes a variety of infectious diseases, including urinary tract infections, bacteremia, pneumonia, and liver... (Review)
Review
is an important gram-negative opportunistic pathogen that causes a variety of infectious diseases, including urinary tract infections, bacteremia, pneumonia, and liver abscesses. With the emergence of multidrug-resistant (MDR) and () strains, the rapid spread of these clinical strains in geography is particularly worrying. However, the detailed mechanisms of virulence and antibiotic resistance in are still not very clear. Therefore, studying and elucidating the pathogenic mechanisms and drug resistance mechanism of infection are important parts of current medical research. In this paper, we systematically summarized the virulence, biofilm, and antibiotic tolerance mechanisms of , and explored the application of whole genome sequencing and global proteomics, which will provide new clues for clinical treatment of .
Topics: Anti-Bacterial Agents; Biofilms; Drug Resistance, Microbial; Genes, Bacterial; Humans; Klebsiella Infections; Klebsiella pneumoniae; Polymerase Chain Reaction; Virulence; Virulence Factors
PubMed: 32872324
DOI: 10.3390/ijerph17176278 -
Toxins Sep 2021is a clinically important pathogen that causes a wide range of human infections, from minor skin infections to severe tissue infection and sepsis. has a high level of... (Review)
Review
is a clinically important pathogen that causes a wide range of human infections, from minor skin infections to severe tissue infection and sepsis. has a high level of antibiotic resistance and is a common cause of infections in hospitals and the community. The rising prevalence of community-acquired methicillin-resistant (CA-MRSA), combined with the important severity of infections in general, has resulted in the frequent use of anti-staphylococcal antibiotics, leading to increasing resistance rates. Antibiotic-resistant continues to be a major health concern, necessitating the development of novel therapeutic strategies. uses a wide range of virulence factors, such as toxins, to develop an infection in the host. Recently, anti-virulence treatments that directly or indirectly neutralize toxins have showed promise. In this review, we provide an update on toxin pathogenic characteristics, as well as anti-toxin therapeutical strategies.
Topics: Anti-Bacterial Agents; Staphylococcus aureus; Toxins, Biological; Virulence; Virulence Factors
PubMed: 34678970
DOI: 10.3390/toxins13100677 -
PLoS Pathogens Oct 2020First described in 2009 in Japan, the emerging multidrug-resistant fungal pathogen Candida auris is becoming a worldwide public health threat that has been attracting... (Review)
Review
First described in 2009 in Japan, the emerging multidrug-resistant fungal pathogen Candida auris is becoming a worldwide public health threat that has been attracting considerable attention due to its rapid and widespread emergence over the past decade. The reasons behind the recent emergence of this fungus remain a mystery to date. Genetic analyses indicate that this fungal pathogen emerged simultaneously in several different continents, where 5 genetically distinct clades of C. auris were isolated from distinct geographical locations. Although C. auris belongs to the CTG clade (its constituent species translate the CTG codon as serine instead of leucine, as in the standard code), C. auris is a haploid fungal species that is more closely related to the haploid and often multidrug-resistant species Candida haemulonii and Candida lusitaniae and is distantly related to the diploid and clinically common fungal pathogens Candida albicans and Candida tropicalis. Infections and outbreaks caused by C. auris in hospitals settings have been rising over the past several years. Difficulty in its identification, multidrug resistance properties, evolution of virulence factors, associated high mortality rates in patients, and long-term survival on surfaces in the environment make C. auris particularly problematic in clinical settings. Here, we review progress made over the past decade on the biological and clinical aspects of C. auris. Future efforts should be directed toward understanding the mechanistic details of its biology, epidemiology, antifungal resistance, and pathogenesis with a goal of developing novel tools and methods for the prevention, diagnosis, and treatment of C. auris infections.
Topics: Antifungal Agents; Candida; Candidiasis; Drug Resistance, Fungal; Humans; Saccharomycetales; Virulence
PubMed: 33091071
DOI: 10.1371/journal.ppat.1008921 -
Molecular Biology Reports Oct 2021Acinetobacter baumannii has become a major concern for scientific attention due to extensive antimicrobial resistance. This resistance causes an increase in mortality... (Review)
Review
Acinetobacter baumannii has become a major concern for scientific attention due to extensive antimicrobial resistance. This resistance causes an increase in mortality rate because strains resistant to antimicrobial agents are a major challenge for physicians and healthcare workers regarding the eradication of either hospital or community-based infections. These strains with emerging resistance are a serious issue for patients in the intensive care unit (ICU). Antibiotic resistance has increased because of the acquirement of mobile genetic elements such as transposons, plasmids, and integrons and causes the prevalence of multidrug resistance strains (MDR). In addition, an increase in carbapenem resistance, which is used as last line antibiotic treatment to eliminate infections with multidrug-resistant Gram-negative bacteria, is a major concern. Carbapenems resistant A. baumannii (CR-Ab) is a worldwide problem. Because these strains are often resistant to all other commonly used antibiotics. Therefore, pathogenic multi-drug resistance A. baumannii (MDR-Ab) associated infections become hard to eradicate. Plasmid-mediated resistance causes outbreaks of extensive drug-resistant. A. baumannii (XDR-Ab). In addition, recent outbreaks relating to livestock and community settings illustrate the existence of large MDR-Ab strain reservoirs within and outside hospital settings. The purpose of this review, proper monitoring, prevention, and treatment are required to control (XDR-Ab) infections. Attachment, the formation of biofilms and the secretion of toxins, and low activation of inflammatory responses are mechanisms used by pathogenic A. baumannii strain. This review will discuss some aspects associated with antibiotics resistance in A. baumannii as well as cover briefly phage therapy as an alternative therapeutic treatment.
Topics: Acinetobacter baumannii; Biofilms; Drug Resistance, Multiple, Bacterial; Hospitals; Host-Pathogen Interactions; Humans; Quorum Sensing; Virulence
PubMed: 34460060
DOI: 10.1007/s11033-021-06690-6 -
Infection, Genetics and Evolution :... Apr 2021Cryptococcus neoformans is a dimorphic fungus that causes lethal meningoencephalitis mainly in immunocompromised individuals. Different morphotypes enable this... (Review)
Review
Cryptococcus neoformans is a dimorphic fungus that causes lethal meningoencephalitis mainly in immunocompromised individuals. Different morphotypes enable this environmental fungus and opportunistic pathogen to adapt to different natural niches and exhibit different levels of pathogenicity in various hosts. It is well-recognized that C. neoformans undergoes bisexual or unisexual reproduction in vitro to generate genotypic, morphotypic, and phenotypic diversity, which augments its ability for adaptation. However, if and how sexual reproduction and the meiotic machinery exert any direct impact on the infection process is unclear. This review summarizes recent discoveries on the regulation of cryptococcal life cycle and morphogenesis, and how they impact cryptococcal pathogenicity. The potential role of the meiotic machinery on ploidy regulation during cryptococcal infection is also discussed. This review aims to stimulate further investigation on links between fungal morphogenesis, sexual reproduction, and virulence.
Topics: Cryptococcus neoformans; Humans; Morphogenesis; Reproduction; Virulence
PubMed: 33497839
DOI: 10.1016/j.meegid.2021.104731 -
Annual Review of Immunology Apr 2023The innate immune system detects pathogens via germline-encoded receptors that bind to conserved pathogen ligands called pathogen-associated molecular patterns (PAMPs).... (Review)
Review
The innate immune system detects pathogens via germline-encoded receptors that bind to conserved pathogen ligands called pathogen-associated molecular patterns (PAMPs). Here we consider an additional strategy of pathogen sensing called effector-triggered immunity (ETI). ETI involves detection of pathogen-encoded virulence factors, also called effectors. Pathogens produce effectors to manipulate hosts to create a replicative niche and/or block host immunity. Unlike PAMPs, effectors are often diverse and rapidly evolving and can thus be unsuitable targets for direct detection by germline-encoded receptors. Effectors are instead often sensed indirectly via detection of their virulence activities. ETI is a viable strategy for pathogen sensing and is used across diverse phyla, including plants, but the molecular mechanisms of ETI are complex compared to simple receptor/ligand-based PAMP detection. Here we survey the mechanisms and functions of ETI, with a particular focus on emerging insights from animal studies. We suggest that many examples of ETI may remain to be discovered, hiding in plain sight throughout immunology.
Topics: Humans; Animals; Pathogen-Associated Molecular Pattern Molecules; Virulence; Innate Immunity Recognition
PubMed: 36750319
DOI: 10.1146/annurev-immunol-101721-031732 -
Microbiology and Molecular Biology... Nov 2019is a highly versatile pathogen capable of causing infections in a wide range of domestic and wild animals as well as in humans and nonhuman primates. Despite over... (Review)
Review
is a highly versatile pathogen capable of causing infections in a wide range of domestic and wild animals as well as in humans and nonhuman primates. Despite over 135 years of research, the molecular basis for the myriad manifestations of pathogenesis and the determinants of phylogeny remain poorly defined. The current availability of multiple genome sequences now makes it possible to delve into the underlying genetic mechanisms of fitness and virulence. Using whole-genome sequences, the genotypes, including the capsular genotypes, lipopolysaccharide (LPS) genotypes, and multilocus sequence types, as well as virulence factor-encoding genes of isolates from different clinical presentations can be characterized rapidly and accurately. Putative genetic factors that contribute to virulence, fitness, host specificity, and disease predilection can also be identified through comparative genome analysis of different isolates. However, although some knowledge about genotypes, fitness, and pathogenesis has been gained from the recent whole-genome sequencing and comparative analysis studies of , there is still a long way to go before we fully understand the pathogenic mechanisms of this important zoonotic pathogen. The quality of several available genome sequences is low, as they are assemblies with relatively low coverage, and genomes of isolates from some uncommon host species are still limited or lacking. Here, we review recent advances, as well as continuing knowledge gaps, in our understanding of determinants contributing to virulence, fitness, host specificity, disease predilection, and phylogeny of .
Topics: Animals; Genetic Variation; Genome, Bacterial; Genomics; Genotype; Host Specificity; Humans; Pasteurella Infections; Pasteurella multocida; Phylogeny; Virulence; Virulence Factors
PubMed: 31484691
DOI: 10.1128/MMBR.00014-19 -
International Journal of Molecular... Jul 2020Microbial virulence factors encompass a wide range of molecules produced by pathogenic microorganisms, enhancing their ability to evade their host defenses and cause...
Microbial virulence factors encompass a wide range of molecules produced by pathogenic microorganisms, enhancing their ability to evade their host defenses and cause disease [...].
Topics: Bacteria; Humans; Virulence; Virulence Factors
PubMed: 32727013
DOI: 10.3390/ijms21155320 -
Trends in Plant Science Feb 2023Botrytis cinerea, a widespread plant pathogen with a necrotrophic lifestyle, causes gray mold disease in many crops. Massive secretion of enzymes and toxins was long... (Review)
Review
Botrytis cinerea, a widespread plant pathogen with a necrotrophic lifestyle, causes gray mold disease in many crops. Massive secretion of enzymes and toxins was long considered to be the main driver of infection, but recent studies have uncovered a rich toolbox for B. cinerea pathogenicity. The emerging picture is of a multilayered infection process governed by the exchange of factors that collectively contribute to disease development. No plant shows complete resistance against B. cinerea, but pattern-triggered plant immune responses have the potential to significantly reduce disease progression, opening new possibilities for producing B. cinerea-tolerant plants. We examine current B. cinerea infection models, highlight knowledge gaps, and suggest directions for future studies.
Topics: Virulence; Botrytis; Plant Diseases
PubMed: 36184487
DOI: 10.1016/j.tplants.2022.08.024 -
Virulence Dec 2024The genus includes human, animal, insect, and plant pathogens as well as many symbionts and harmless bacteria. Within this genus are and the complex, with four human... (Review)
Review
The genus includes human, animal, insect, and plant pathogens as well as many symbionts and harmless bacteria. Within this genus are and the complex, with four human pathogenic species that are highly related at the genomic level including the causative agent of plague, . Extensive laboratory, field work, and clinical research have been conducted to understand the underlying pathogenesis and zoonotic transmission of these pathogens. There are presently more than 500 whole genome sequences from which an evolutionary footprint can be developed that details shared and unique virulence properties. Whereas the virulence of now seems in apparent homoeostasis within its flea transmission cycle, substantial evolutionary changes that affect transmission and disease severity continue to ndergo apparent selective pressure within the other that cause intestinal diseases. In this review, we will summarize the present understanding of the virulence and pathogenesis of , highlighting shared mechanisms of virulence and the differences that determine the infection niche and disease severity.
Topics: Animals; Humans; Yersinia; Virulence; Yersinia pestis; Plague; Yersinia Infections
PubMed: 38389313
DOI: 10.1080/21505594.2024.2316439