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Microbiology Spectrum Apr 2022Achromobacter denitrificans is an environmental opportunistic pathogen that is infecting a large number of immunocompromised patients. A more recently identified strain...
Achromobacter denitrificans is an environmental opportunistic pathogen that is infecting a large number of immunocompromised patients. A more recently identified strain from the historical collection of strains of Achromobacter denitrificans is Achromobacter mucicolens. In hosts with a variety of underlying diseases, spp. can induce a wide spectrum of disorders. Because of the bacterium's intrinsic genetic constitution and resistance gained over time, antibiotics are challenged to handle Due to the fact that is rare and its taxonomy is not completely understood, it is difficult to define clinical symptoms, acquisition risk factors, and thus the best therapeutic course of action. To help comprehend this intrinsic and acquired resistance, we analyzed the entire genome of the strain and utilized bioinformatics methods to estimate the strain's probable drug resistance profile. In our study, we have isolated and cultured a clinically important strain and subjected it to antimicrobial susceptibility tests against antibiotics in the Vitek 2 testing system. The strain's genome sequence as well as an investigation of 27 of its phenotypic traits provides important information regarding this pathogen. The genome of this strain possesses a number of antibiotic resistance genes that code for efflux pump systems and other antibiotic-regulating as well as -modifying enzymes. Our research analysis predicted genes involved in drug resistance, including genes for efflux pump systems, antibiotic efflux, antibiotic inactivation, and antibiotic target alteration. studies validated the genomic evidence for its ability to exhibit resistance against a wide range of antibiotics. Our investigation paves the way for more research on understanding the functioning of the key discovered genes that contribute toward the pathogenicity of and hence gives new information and treatment options for this emerging pathogen. species are well-known opportunistic human pathogens that can be found in water and soil and most commonly in hospital settings. They thrive in immunocompromised individuals, producing sporadic cases of pneumonia, septicemia, peritonitis, urinary tract infections, and other illnesses. strains are inherently resistant to a wide spectrum of antibiotics, making them difficult to treat promptly. The strain under study, , was notably resistant to various antibiotics, and the infection could be controlled only after several rounds of prescription medications at different doses. This consumed a lot of time and put the already immunosuppressed leukemic patient through a great ordeal. The study aimed to raise awareness about the importance of the bacterium's lethality, and doctors should evaluate the bacterium's potential for resistance before prescribing antibiotics. Sanitation and other precautions should also be implemented in hospitals and other public places.
Topics: Achromobacter; Achromobacter denitrificans; Anti-Bacterial Agents; Drug Resistance, Microbial; Genomics; Humans; Microbial Sensitivity Tests
PubMed: 35377213
DOI: 10.1128/spectrum.01916-21 -
BMC Infectious Diseases Aug 2021Bordetella avium, an aerobic bacterium that rarely causes infection in humans, is a species of Bordetella that generally inhabits the respiratory tracts of turkeys and...
BACKGROUND
Bordetella avium, an aerobic bacterium that rarely causes infection in humans, is a species of Bordetella that generally inhabits the respiratory tracts of turkeys and other birds. It causes a highly contagious bordetellosis. Few reports describe B. avium as a causative agent of eye-related infections.
CASE PRESENTATION
We report a case of acute infectious endophthalmitis associated with infection by B. avium after open trauma. After emergency vitrectomy and subsequent broad-spectrum antibiotic treatment, the infection was controlled successfully, and the patient's vision improved.
CONCLUSIONS
B. avium can cause infection in the human eye, which can manifest as acute purulent endophthalmitis. Nanopore targeted sequencing technology can quickly identify this organism. Emergency vitrectomy combined with lens removal and silicone oil tamponade and the early application of broad-spectrum antibiotics are key for successful treatment.
Topics: Bordetella; Bordetella avium; Cataract Extraction; Endophthalmitis; Humans; Vitrectomy
PubMed: 34412580
DOI: 10.1186/s12879-021-06546-1 -
Current Opinion in Microbiology Feb 2009Here we review the Bordetella virulence secretome with an emphasis on factors that translocate into target cells. Recent advances in understanding the functions of... (Review)
Review
Here we review the Bordetella virulence secretome with an emphasis on factors that translocate into target cells. Recent advances in understanding the functions of adenylate cyclase toxin, a type 1 secretion system (T1SS) substrate, and pertussis toxin, a type IV secretion system (T4SS) substrate, are briefly described and a compilation of additional secretion systems and secreted factors is provided. Particular attention is devoted to the Bsc type III secretion system (T3SS) and controversies surrounding it. Efforts to identify effector proteins, characterize in vitro and in vivo phenotypes, and the potential role of type III secretion during human infections are discussed.
Topics: Bacterial Proteins; Bacterial Toxins; Bordetella; Host-Pathogen Interactions; Humans; Membrane Transport Proteins; Protein Transport; Virulence Factors
PubMed: 19186097
DOI: 10.1016/j.mib.2009.01.001 -
FEMS Microbiology Reviews May 2011Pertussis, or whooping cough, is a highly contagious, acute respiratory disease of humans that is caused by the Gram-negative bacterial pathogen Bordetella pertussis. In... (Review)
Review
Pertussis, or whooping cough, is a highly contagious, acute respiratory disease of humans that is caused by the Gram-negative bacterial pathogen Bordetella pertussis. In the face of extensive global vaccination, this extremely monomorphic pathogen has persisted and re-emerged, causing approximately 300,000 deaths each year. In this review, we discuss the interaction of B. pertussis with the host mucosal epithelium and immune system. Using a large number of virulence factors, B. pertussis is able to create a niche for colonization in the human respiratory tract. The successful persistence of this pathogen is mainly due to its ability to interfere with almost every aspect of the immune system, from the inhibition of complement- and phagocyte-mediated killing to the suppression of T- and B-cell responses. Based on these insights, we delineate ideas for the rational design of improved vaccines that can target the 'weak spots' in the pathogenesis of this highly successful pathogen.
Topics: Animals; Bordetella pertussis; Humans; Mice; Virulence Factors; Whooping Cough
PubMed: 21204863
DOI: 10.1111/j.1574-6976.2010.00257.x -
Microbiology Spectrum Apr 2016Since the first description of Bordetella holmesii in 1995, almost 100 publications have contributed to the increasing knowledge of this emerging bacterium. Although... (Review)
Review
Since the first description of Bordetella holmesii in 1995, almost 100 publications have contributed to the increasing knowledge of this emerging bacterium. Although first reported to induce bacteremia mainly in immunocompromised patients, it has also been isolated in healthy persons and has shown the capacity to induce pertussis-like symptoms and other clinical entities, such as meningitis, arthritis, or endocarditis. Respiratory diseases are generally less severe than those induced by Bordetella pertussis. However, B. holmesii was found to have a higher capacity of invasiveness given the various infection sites in which it was isolated. The diagnosis is difficult, particularly as it is a slow-growing organism but also because respiratory infections are systematically misdiagnosed as B. pertussis. Treatment is delicate, as its susceptibility to macrolides (prescribed in respiratory infections) and ceftriaxone (used in invasive disease) is challenged. Regarding prevention, there is no consensus on prophylactic treatment following index cases and no vaccine is available. Epidemiological data are also sparse, with few prevalence studies available. In this chapter, we provide an overview of the current state of knowledge on B. holmesii.
Topics: Bordetella; Bordetella Infections; Ceftriaxone; Humans; Macrolides
PubMed: 27227292
DOI: 10.1128/microbiolspec.EI10-0003-2015 -
MBio Oct 2017Nearly all virulence factors in are activated by a master two-component system, BvgAS, composed of the sensor kinase BvgS and the response regulator BvgA. When BvgS is...
Nearly all virulence factors in are activated by a master two-component system, BvgAS, composed of the sensor kinase BvgS and the response regulator BvgA. When BvgS is active, BvgA is phosphorylated (BvgA~P), and virulence-activated genes (s) are expressed [Bvg(+) mode]. When BvgS is inactive and BvgA is not phosphorylated, virulence-repressed genes (s) are induced [Bvg(-) mode]. Here, we have used transcriptome sequencing (RNA-seq) and reverse transcription-quantitative PCR (RT-qPCR) to define the BvgAS-dependent regulon of Tohama I. Our analyses reveal more than 550 BvgA-regulated genes, of which 353 are newly identified. BvgA-activated genes include those encoding two-component systems (such as ), multiple other transcriptional regulators, and the extracytoplasmic function (ECF) sigma factor , which is needed for type 3 secretion system (T3SS) expression, further establishing the importance of BvgA~P as an apex regulator of transcriptional networks promoting virulence. Using transcription, we demonstrate that the promoter for is directly activated by BvgA~P. BvgA-FeBABE cleavage reactions identify BvgA~P binding sites centered at positions -41.5 and -63.5 in Most importantly, we show for the first time that genes for multiple and varied metabolic pathways are significantly upregulated in the Bvg(-) mode. These include genes for fatty acid and lipid metabolism, sugar and amino acid transporters, pyruvate dehydrogenase, phenylacetic acid degradation, and the glycolate/glyoxylate utilization pathway. Our results suggest that metabolic changes in the Bvg(-) mode may be participating in bacterial survival, transmission, and/or persistence and identify over 200 new s that can be tested for function. Within the past 20 years, outbreaks of whooping cough, caused by , have led to respiratory disease and infant mortalities, despite good vaccination coverage. This is due, at least in part, to the introduction of a less effective acellular vaccine in the 1990s. It is crucial, then, to understand the molecular basis of growth and infection. The two-component system BvgA (response regulator)/BvgS (histidine kinase) is the master regulator of virulence genes. We report here the first RNA-seq analysis of the BvgAS regulon in , revealing that more than 550 genes are regulated by BvgAS. We show that genes for multiple and varied metabolic pathways are highly regulated in the Bvg(-) mode (absence of BvgA phosphorylation). Our results suggest that metabolic changes in the Bvg(-) mode may be participating in bacterial survival, transmission, and/or persistence.
Topics: Bacterial Proteins; Bordetella pertussis; Gene Expression Regulation, Bacterial; Genes, Regulator; High-Throughput Nucleotide Sequencing; Promoter Regions, Genetic; Regulon; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Transcription Factors; Transcriptome; Virulence
PubMed: 29018122
DOI: 10.1128/mBio.01526-17 -
MBio May 2019encodes and expresses a flagellar apparatus. In contrast, , the causative agent of whooping cough, has historically been described as a nonmotile and nonflagellated...
encodes and expresses a flagellar apparatus. In contrast, , the causative agent of whooping cough, has historically been described as a nonmotile and nonflagellated organism. The previous statements that was a nonmotile organism were consistent with a stop codon located in the flagellar biosynthesis gene, , discovered when the Tohama I genome was sequenced and analyzed by Parkhill et al. in 2003 (J. Parkhill, M. Sebaihia, A. Preston, L. D. Murphy, et al., Nat Genet, 35:32-40, 2003, https://doi.org/10.1038/ng1227). The stop codon has subsequently been found in all annotated genomes. Parkhill et al. also showed, however, that contains all genetic material required for flagellar synthesis and function. We and others have determined by various transcriptomic analyses that these flagellar genes are differentially regulated under a variety of growth conditions. In light of these data, we tested for motility and found that both laboratory-adapted strains and clinical isolates can be motile. Upon isolation of motile , we discovered flagellum-like structures on the surface of the bacteria. motility appears to occur primarily in the Bvg(-) phase, consistent with regulation present in Motility can also be induced by the presence of fetal bovine serum. These observations demonstrate that can express flagellum-like structures, and although it remains to be determined if expresses flagella during infection or if motility and/or flagella play roles during the cycle of infection and transmission, it is clear that these data warrant further investigation. This report provides evidence for motility and expression of flagella by , a bacterium that has been reported as nonmotile since it was first isolated and studied. As with , cells can express and assemble a flagellum-like structure on their surface, which in other organisms has been implicated in several important processes that occur The discovery that is motile raises many questions, including those regarding the mechanisms of regulation for flagellar gene and protein expression and, importantly, the role of flagella during infection. This novel observation provides a foundation for further study of flagella and motility in the contexts of infection and transmission.
Topics: Bordetella bronchiseptica; Bordetella pertussis; Flagella; Flagellin; Gene Expression Regulation, Bacterial; Movement
PubMed: 31088927
DOI: 10.1128/mBio.00787-19 -
MBio Oct 2022Hereditary symbioses have the potential to drive transgenerational effects, yet the mechanisms responsible for transmission of heritable plant symbionts are still poorly...
Hereditary symbioses have the potential to drive transgenerational effects, yet the mechanisms responsible for transmission of heritable plant symbionts are still poorly understood. The leaf symbiosis between and the bacterium offers an appealing model system to study how heritable bacteria are transmitted to the next generation. Here, we demonstrate that inoculation of apical buds with a bacterial suspension is sufficient to colonize newly formed leaves and propagules, and to ensure transmission to the next plant generation. Flagellar motility is not required for movement inside the plant but is important for the colonization of new hosts. Further, tissue-specific regulation of putative symbiotic functions highlights the presence of two distinct subpopulations of bacteria in the leaf gland and at the shoot meristem. We propose that bacteria in the leaf gland dedicate resources to symbiotic functions, while dividing bacteria in the shoot tip ensure successful colonization of meristematic tissue, glands, and propagules. Compartmentalization of intrahost populations together with tissue-specific regulation may serve as a robust mechanism for the maintenance of mutualism in leaf symbiosis. Hereditary symbioses with bacteria are common in the animal kingdom, but relatively unexplored in plants. Several plant species form associations with bacteria in their leaves, which is called leaf symbiosis. These associations are highly specific, but the mechanisms responsible for symbiont transmission are poorly understood. Using the association between the yam species and as a model leaf symbiosis, we show that bacteria are distributed to specific leaf structures via association with shoot meristems. Flagellar motility is required for initial infection but does not contribute to spread within host tissue. We also provide evidence that bacterial subpopulations at the meristem or in the symbiotic leaf gland differentially express key symbiotic genes. We argue that this separation of functional symbiont populations, coupled with tight control over bacterial infection and transmission, explain the evolutionary robustness of leaf symbiosis. These findings may provide insights into how plants may recruit and maintain beneficial symbionts at the leaf surface.
Topics: Animals; Symbiosis; Alcaligenaceae; Plant Leaves; Bacteria; Plants
PubMed: 36040028
DOI: 10.1128/mbio.01033-22 -
Microbiological Reviews Dec 1980
Review
Topics: Animals; Anti-Bacterial Agents; Antigens, Bacterial; Bacterial Toxins; Bordetella; Bordetella Infections; Humans; Respiratory Tract Infections
PubMed: 7010115
DOI: 10.1128/mr.44.4.722-738.1980 -
Microbiology Spectrum Mar 2019Bacteria use a variety of mechanisms to translocate proteins from the cytoplasm, where they are synthesized, to the cell surface or extracellular environment or directly... (Review)
Review
Bacteria use a variety of mechanisms to translocate proteins from the cytoplasm, where they are synthesized, to the cell surface or extracellular environment or directly into other cells, where they perform their ultimate functions. Type V secretion systems (T5SS) use β-barrel transporter domains to export passenger domains across the outer membranes of Gram-negative bacteria. Distinct among T5SS are type Vb or two-partner secretion (TPS) systems in which the transporter and passenger are separate proteins, necessitating a mechanism for passenger-translocator recognition in the periplasm and providing the potential for reuse of the translocator. This review describes current knowledge of the TPS translocation mechanism, using filamentous hemagglutinin (FHA) and its transporter FhaC as a model. We present the hypothesis that the TPS pathway may be a general mechanism for contact-dependent delivery of toxins to target cells.
Topics: Adhesins, Bacterial; Bacterial Outer Membrane Proteins; Bordetella; Bordetella pertussis; Gram-Negative Bacteria; Hemagglutinins; Membrane Transport Proteins; Models, Molecular; Secretory Pathway; Type V Secretion Systems; Virulence; Virulence Factors, Bordetella; Whooping Cough
PubMed: 30927348
DOI: 10.1128/microbiolspec.PSIB-0024-2018