Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 56.350
Filtrar
1.
Virulence ; 14(1): 2150455, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36599817

RESUMEN

Paracoccin (PCN), a Paracoccidioides brasiliensis glycoprotein, has been reported to play roles in fungal biology and paracoccidioidomycosis pathogenesis. Lectin and chitinase domains account for the PCN's dual roles as an immunomodulatory agent and virulence factor. Soluble PCN injected in P. brasiliensis infected mice, by interacting with TLRs' N-glycans, drives the host immune response toward a protective Th1 axis. Otherwise, mice infection with yeasts overexpressing PCN (ov-PCN) revealed that PCN acts as a fungal virulence factor, thanks to its chitinase activity on the cell wall, resulting in resistance to phagocytes' fungicidal activity and development of severe paracoccidioidomycosis. Because antifungal drug administration follows the disease diagnosis, we studied the PCN effect on yeast resistance or susceptibility to antifungal agents. Using a paracoccidioidomycosis model developed in Galleria mellonella larvae, we confirmed the observation, in the murine host, that ov-PCN yeasts display maximum virulence compared to wild-type (wt-PCN) or PCN-silenced (kd-PCN) yeasts. PCN overexpression accounted for the highest susceptibility of P. brasiliensis to antifungal and reduced relative mRNA expression of genes encoding proteins related to cell wall remodeling. The lowest virulence, detected in infection with kd-PCN yeasts, correlated with the lowest susceptibility to antifungals and impact on genes for cell wall remodeling. So, we defined that the grade of endogenous PCN production influences the P. brasiliensis virulence and susceptibility to antifungal drugs, as well as the expression of genes related to cell wall remodeling. We postulate that this variable gene expression is mechanistically associated with P. brasiliensis virulence changes.


Asunto(s)
Mariposas Nocturnas , Paracoccidioides , Paracoccidioidomicosis , Animales , Ratones , Antifúngicos/farmacología , Antifúngicos/metabolismo , Virulencia , Larva , Paracoccidioidomicosis/microbiología , Paracoccidioides/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Mariposas Nocturnas/metabolismo , Factores de Virulencia/genética , Factores de Virulencia/metabolismo
2.
Biomolecules ; 13(1)2023 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-36671522

RESUMEN

Campylobacter jejuni is likely the most common bacterial cause of gastroenteritis worldwide, responsible for millions of cases of inflammatory diarrhea characterized by severe abdominal cramps and blood in the stool. Further, C. jejuni infections are associated with post-infection sequelae in developed countries and malnutrition and growth-stunting in low- and middle-income countries. Despite the increasing prevalence of the disease, campylobacteriosis, and the recognition that this pathogen is a serious health threat, our understanding of C. jejuni pathogenesis remains incomplete. In this review, we focus on the Campylobacter secretion systems proposed to contribute to host-cell interactions and survival in the host. Moreover, we have applied a genomics approach to defining the structural and mechanistic features of C. jejuni type III, IV, and VI secretion systems. Special attention is focused on the flagellar type III secretion system and the prediction of putative effectors, given that the proteins exported via this system are essential for host cell invasion and the inflammatory response. We conclude that C. jejuni does not possess a type IV secretion system and relies on the type III and type VI secretion systems to establish a niche and potentiate disease.


Asunto(s)
Infecciones por Campylobacter , Campylobacter jejuni , Gastroenteritis , Humanos , Campylobacter jejuni/metabolismo , Virulencia , Proteínas Bacterianas/metabolismo , Infecciones por Campylobacter/metabolismo , Infecciones por Campylobacter/microbiología , Factores de Virulencia/metabolismo
3.
Int J Mol Sci ; 24(2)2023 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-36674819

RESUMEN

Salmonella Typhimurium is a Gram-negative intestinal pathogen that can infect humans and a variety of animals, causing gastroenteritis or serious systemic infection. Replication within host macrophages is essential for S. Typhimurium to cause systemic infection. By analyzing transcriptome data, the expression of yhjC gene, which encodes a putative regulator in S. Typhimurium, was found to be significantly up-regulated after the internalization of Salmonella by macrophages. Whether yhjC gene is involved in S. Typhimurium systemic infection and the related mechanisms were investigated in this study. The deletion of yhjC reduced the replication ability of S. Typhimurium in macrophages and decreased the colonization of S. Typhimurium in mouse systemic organs (liver and spleen), while increasing the survival rate of the infected mice, suggesting that YhjC protein promotes systemic infection by S. Typhimurium. Furthermore, by using transcriptome sequencing and RT-qPCR assay, the transcription of several virulence genes, including spvD, iroCDE and zraP, was found to be down-regulated after the deletion of yhjC. Electrophoretic mobility shift assay showed that YhjC protein can directly bind to the promoter region of spvD and zraP to promote their transcription. These findings suggest that YhjC contributes to the systemic virulence of S. Typhimurium via the regulation of multiple virulence genes and YhjC could represent a promising target to control S. Typhimurium infection.


Asunto(s)
Salmonelosis Animal , Salmonella typhimurium , Humanos , Ratones , Animales , Salmonella typhimurium/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Virulencia/genética , Factores de Transcripción/metabolismo , Factores de Virulencia/genética
4.
J Agric Food Chem ; 71(3): 1405-1416, 2023 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-36644843

RESUMEN

Infestation of rice with the bacterium Xanthomonas oryzae pv. oryzicola (Xoc) causes the serious disease bacterial leaf streak (BLS). We studied the effect of ethylicin, a broad-spectrum bactericide, on Xoc both in vivo and in vitro. Ethylicin increases the defensive enzyme activities and defensive genes expression of rice. Ethylicin also significantly inhibited Xoc activity in vitro compared with other commercial bactericides. The half-maximal effective concentration (EC50) of ethylicin was 2.12 µg/mL. It has been shown that ethylicin can inhibit Xoc quorum sensing through the production of extracellular polysaccharides and enzymes, which disrupt the Xoc cell membrane. We used proteomic analysis to identify two oxidative phosphorylation pathway proteins (ACU12_RS13405 and ACU12_RS13355) which affected the virulence of Xoc and validated them using quantitative real-time polymerase chain reaction (qRT-PCR). The results indicate that ethylicin can increase the defense responses of rice and control Xoc proliferation.


Asunto(s)
Oryza , Xanthomonas , Proteínas Bacterianas/metabolismo , Proteómica , Virulencia , Xanthomonas/genética , Oryza/metabolismo , Enfermedades de las Plantas/microbiología
5.
BMC Microbiol ; 23(1): 27, 2023 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-36690941

RESUMEN

BACKGROUND: Listeria monocytogenes are Gram-positive rods, which are the etiological factor of listeriosis. L. monocytogenes quickly adapts to changing environmental conditions. Since the main source of rods is food, its elimination from the production line is a priority. The study aimed to evaluate the influence of selected stress factors on the growth and survival of L. monocytogenes strains isolated from food products and clinical material. RESULTS: We distinguished fifty genetically different strains of L. monocytogenes (PFGE method). Sixty-two percent of the tested strains represented 1/2a-3a serogroup. Sixty percent of the rods possessed ten examined virulence genes (fbpA, plcA, hlyA, plcB, inlB, actA, iap, inlA, mpl, prfA). Listeria Pathogenicity Island 1 (LIPI-1) was demonstrated among 38 (76.0%) strains. Majority (92.0%) of strains (46) were sensitive to all examined antibiotics. The most effective concentration of bacteriophage (inhibiting the growth of 22 strains; 44.0%) was 5 × 108 PFU. In turn, the concentration of 8% of NaCl was enough to inhibit the growth of 31 strains (62.0%). The clinical strain tolerated the broadest pH range (3 to 10). Five strains survived the 60-min exposure to 70˚C, whereas all were alive at each time stage of the cold stress experiment. During the stress of cyclic freezing-defrosting, an increase in the number of bacteria was shown after the first cycle, and a decrease was only observed after cycle 3. The least sensitive to low nutrients content were strains isolated from frozen food. The high BHI concentration promoted the growth of all groups. CONCLUSIONS: Data on survival in stress conditions can form the basis for one of the hypotheses explaining the formation of persistent strains. Such studies are also helpful for planning appropriate hygiene strategies within the food industry.


Asunto(s)
Listeria monocytogenes , Listeriosis , Humanos , Microbiología de Alimentos , Listeriosis/microbiología , Virulencia/genética , Factores de Virulencia/genética , Proteínas Bacterianas/genética
6.
Zhongguo Dang Dai Er Ke Za Zhi ; 25(1): 1-4, 2023 Jan 15.
Artículo en Chino | MEDLINE | ID: mdl-36655656

RESUMEN

Since the global pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2020, the virus has been evolving through mutations to acquire enhanced infectivity but reduced virulence. With a wide vaccination coverage among Chinese population, China is entering a new stage of SARS-CoV-2 infection control. The Working Group for the Prevention and Control of Neonatal SARS-CoV-2 Infection in the Perinatal Period of the Editorial Committee of Chinese Journal of Contemporary Pediatrics released the first and second editions of perinatal and neonatal management plan for prevention and control of SARS-CoV-2 infection in January and March 2020, respectively. In order to follow up new prevention and control needs, it is necessary to update the management plan to better guide clinical practice. Therefore, the Working Group formulated the 3rd-edition plan.


Asunto(s)
COVID-19 , Embarazo , Recién Nacido , Femenino , Humanos , Niño , COVID-19/prevención & control , COVID-19/epidemiología , SARS-CoV-2 , Pandemias/prevención & control , China/epidemiología , Virulencia
7.
Genome Med ; 15(1): 3, 2023 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-36658655

RESUMEN

BACKGROUND: Klebsiella pneumoniae (Kp) Gram-negative bacteria cause nosocomial infections and rapidly acquire antimicrobial resistance (AMR), which makes it a global threat to human health. It also has a comparatively rare hypervirulent phenotype that can lead to severe disease in otherwise healthy individuals. Unlike classic Kp, canonical hypervirulent strains usually have limited AMR. However, after initial case reports in 2015, carbapenem-resistant hypervirulent Kp has increased in prevalence, including in China, but there is limited understanding of its burden  in other geographical regions. METHODS: Here, we examined the largest collection of publicly available sequenced Kp isolates (n=13,178), containing 1603 different sequence types (e.g. ST11 15.0%, ST258 9.5%), and 2174 (16.5%) hypervirulent strains. We analysed the plasmid replicons and carbapenemase and siderophore encoding genes to understand the movement of hypervirulence and AMR genes located on plasmids, and their convergence in carbapenem-resistant hypervirulent Kp. RESULTS: We identified and analysed 3034 unique plasmid replicons to inform the epidemiology and transmission dynamics of carbapenem-resistant hypervirulent Kp (n=1028, 7.8%). We found several outbreaks globally, including one involving ST11 strains in China and another of ST231 in Asia centred on India, Thailand, and Pakistan. There was evidence of global flow of Kp, including across multiple continents. In most cases, clusters of Kp isolates are the result of hypervirulence genes entering classic strains, instead of carbapenem resistance genes entering canonical hypervirulent ones. CONCLUSIONS: Our analysis demonstrates the importance of plasmid analysis in the monitoring of carbapenem-resistant and hypervirulent strains of Kp. With the growing adoption of omics-based technologies for clinical and surveillance applications, including in geographical regions with gaps in data and knowledge (e.g. sub-Saharan Africa), the identification of the spread of AMR will inform infection control globally.


Asunto(s)
Carbapenémicos , Infecciones por Klebsiella , Humanos , Carbapenémicos/farmacología , Klebsiella pneumoniae , Virulencia/genética , Plásmidos/genética , beta-Lactamasas/genética , Genómica , Antibacterianos/farmacología , Infecciones por Klebsiella/epidemiología , Infecciones por Klebsiella/microbiología
8.
Viruses ; 15(1)2023 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-36680295

RESUMEN

Equine viral arteritis is an infectious disease of equids caused by equine arteritis virus (EAV), an RNA virus of the family Arteriviridae. Dendritic cells (DC) are important modulators of the immune response with the ability to present antigen to naïve T cells and can be generated in vitro from monocytes (MoDC). DC are important targets for many viruses and this interaction is crucial for the establishment-or rather not-of an anti-viral immunity. Little is known of the effect EAV has on host immune cells, particularly DC. To study the interaction of eqDC with EAV in vitro, an optimized eqMoDC system was used, which was established in a previous study. MoDC were infected with strains of different genotypes and pathogenicity. Virus replication was determined through titration and qPCR. The effect of the virus on morphology, phenotype and function of cells was assessed using light microscopy, flow cytometry and in vitro assays. This study confirms that EAV replicates in monocytes and MoDC. The replication was most efficient in mature MoDC, but variable between strains. Only the virulent strain caused a significant down-regulation of certain proteins such as CD14 and CD163 on monocytes and of CD83 on mature MoDC. Functional studies conducted after infection showed that EAV inhibited the endocytic and phagocytic capacity of Mo and mature MoDC with minimal effect on immature MoDC. Infected MoDC showed a reduced ability to stimulate T cells. Ultimately, EAV replication resulted in an apoptosis-mediated cell death. Thus, EAV evades the host anti-viral immunity both by inhibition of antigen presentation early after infection and through killing infected DC during replication.


Asunto(s)
Equartevirus , Animales , Caballos , Equartevirus/genética , Monocitos , Virulencia , Células Dendríticas , Diferenciación Celular
9.
Food Microbiol ; 111: 104190, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-36681396

RESUMEN

Temperature is a major determinant of Listeria (L.) monocytogenes adherence and biofilm formation on abiotic surfaces. However, its role on gene regulation of L. monocytogenes mature biofilms has not been investigated. In the present study, we aimed to evaluate the impact of temperature up- and down-shift on L. monocytogenes biofilms gene transcription. L. monocytogenes strain EGD-e biofilms were first developed on stainless steel surfaces in Brain Heart Infusion broth at 20 °C for 48 h. Then, nutrient broth was renewed, and mature biofilms were exposed to 10 °C, 20 °C or 37 °C for 24 h. Biofilm cells were harvested and RNA levels of plcA, prfA, hly, mpl, plcB, sigB, bapL, fbpA, fbpB, lmo2178, lmo0880, lmo0160, lmo1115, lmo 2089, lmo2576, lmo0159 and lmo0627 were evaluated by quantitative RT-PCR. The results revealed an over-expression of all genes tested in biofilm cells compared to planktonic cells. When biofilms were further allowed to proliferate at 20 °C for 24 h, the transcription levels of key virulence, stress response and putative binding proteins genes plcA, sigB, fbpA, fbpB, lmo1115, lmo0880 and lmo2089 decreased. A temperature-dependent transcription for sigB, plcA, hly, and lmo2089 genes was observed after biofilm proliferation at 10 °C or 37 °C. Our findings suggest that temperature differentially affects gene regulation of L. monocytogenes mature biofilms, thus modulating attributes such as virulence, stress response and pathogenesis.


Asunto(s)
Listeria monocytogenes , Listeria , Listeria monocytogenes/fisiología , Virulencia/genética , Temperatura , Biopelículas , Listeria/genética
10.
Food Microbiol ; 111: 104192, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-36681391

RESUMEN

Many niche-dependent barriers along the poultry production continuum favour the survival of certain Salmonella serovars over others. Historically, the presence of particular serovars has been determined by niche-specific genes which encode resistance to selective pressures such as host defenses and industrial antimicrobial practices. Over the past decade, Canada has witnessed unexplained shifts in the Salmonella landscape in the poultry sector. Several formerly minor Salmonella serovars, including S. Kentucky and S. Reading, have recently increased in prevalence in live chickens and turkeys, respectively, in British Columbia (BC). The purpose of this research was to investigate the genomic features of the top poultry-associated Salmonella spp. in BC, to probe for serovar-specific characteristics that could address the recently shifting balance of serovars along the poultry continuum. By examining the quantity and diversity of antimicrobial resistance (AMR) genes, virulence factors (VFs), Salmonella Pathogenicity Islands (SPIs), and plasmids across 50 poultry-associated S. enterica isolates using whole genome sequencing and antimicrobial resistance profiling, we have identified serovar-specific differences that likely influence niche survival. Specifically, isolates in our collection from predominantly human pathogenic serovars (S. I 4, [5], 12:i: , S. Typhimurium, and S. Enteritidis) were found to share the IncFIB(S) and IncFII(S) plasmids which carry important VFs known to aid in human host infection. Additionally, these strains held the lowest number of AMR genes, and the highest number of unique SPIs which also facilitate virulence. However, other serovars containing a greater diversity and abundance of resistance genes have been increasing across the poultry sector. S. Kentucky was found to carry unique AMR genes, VFs, SPIs, and plasmids that could bolster persistence in farm and processing environments. Overall, S. Kentucky also had comparatively high levels of intra-serovar genetic variability when compared to other prominent serovars from our collection. In addition, one of our two S. Reading isolates had high carriage of both AMR genes and VFs relative to other isolates in our collection. As the poultry-associated Salmonella landscape continues to evolve in Canada, future studies should monitor the genetic composition of prominent serovars across poultry production to maintain up-to-date risk assessments of these foodborne pathogens to consumers.


Asunto(s)
Aves de Corral , Salmonella enterica , Humanos , Animales , Virulencia/genética , Colombia Británica , Kentucky , Pollos , Salmonella , Factores de Virulencia/genética , Serogrupo , Farmacorresistencia Bacteriana Múltiple/genética , Antibacterianos/farmacología
12.
World J Gastroenterol ; 29(1): 190-199, 2023 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-36683715

RESUMEN

BACKGROUND: In recent years, associations between specific virulence markers of Helicobacter pylori (H. pylori) and gastrointestinal disorders have been suggested. AIM: To investigate the presence of virulence factors including vacuolating cytotoxin A genotypes (s1m1, s1m2, s2m1, and s2m2), cytotoxin-associated gene A (CagA), and urease activity in H. pylori strains isolated from Arab and Jewish populations in northern Israel and to assess associations between these factors and patients' demographics and clinical outcomes. METHODS: Patients (n = 108) who underwent gastroscopy at the Baruch Padeh Medical Center, Poriya due to symptomatic gastroduodenal pathologies as part of H. pylori diagnosis were enrolled in the study. Gastric biopsy specimens were collected from the antrum of the stomach. Clinical condition was assessed by clinical pathology tests. Bacteria were isolated on modified BD Helicobacter Agar (BD Diagnostics, Sparks, MD, United States). Bacterial DNA was extracted, and PCR was performed to detect CagA and vacuolating cytotoxin A genes. Urease activity was assessed using a rapid urease test. RESULTS: A significant correlation was found between disease severity and patient ethnicity (P = 0.002). A significant correlation was found between CagA presence and the s1m1 genotype (P = 0.02), which is considered the most virulent genotype. Further, a higher level of urease activity was associated with isolates originating from the Jewish population. Moreover, higher urease activity levels were measured among CagA-/s1m1 and CagA-/s2m2 isolates. CONCLUSION: Our study highlights the importance of incorporating molecular methods for detection of virulence markers of H. pylori in order to tailor optimal treatments for each patient. Further investigation should be performed regarding associations between H. pylori virulence factors and ethnicity.


Asunto(s)
Infecciones por Helicobacter , Helicobacter pylori , Humanos , Adulto , Proteínas Bacterianas/genética , Antígenos Bacterianos/genética , Virulencia/genética , Ureasa , Factores de Virulencia/genética , Genotipo , Infecciones por Helicobacter/epidemiología
13.
Int J Oral Sci ; 15(1): 4, 2023 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-36631439

RESUMEN

Periodontitis is the most widespread oral disease and is closely related to the oral microbiota. The oral microbiota is adversely affected by some pharmacologic treatments. Systemic antibiotics are widely used for infectious diseases but can lead to gut dysbiosis, causing negative effects on the human body. Whether systemic antibiotic-induced gut dysbiosis can affect the oral microbiota or even periodontitis has not yet been addressed. In this research, mice were exposed to drinking water containing a cocktail of four antibiotics to explore how systemic antibiotics affect microbiota pathogenicity and oral bone loss. The results demonstrated, for the first time, that gut dysbiosis caused by long-term use of antibiotics can disturb the oral microbiota and aggravate periodontitis. Moreover, the expression of cytokines related to Th17 was increased while transcription factors and cytokines related to Treg were decreased in the periodontal tissue. Fecal microbiota transplantation with normal mice feces restored the gut microbiota and barrier, decreased the pathogenicity of the oral microbiota, reversed the Th17/Treg imbalance in periodontal tissue, and alleviated alveolar bone loss. This study highlights the potential adverse effects of long-term systemic antibiotics-induced gut dysbiosis on the oral microbiota and periodontitis. A Th17/Treg imbalance might be related to this relationship. Importantly, these results reveal that the periodontal condition of patients should be assessed regularly when using systemic antibiotics in clinical practice.


Asunto(s)
Microbiota , Periodontitis , Humanos , Ratones , Animales , Disbiosis , Antibacterianos/farmacología , Virulencia , Periodontitis/inducido químicamente , Citocinas
14.
Emerg Microbes Infect ; 12(1): 2165969, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36628606

RESUMEN

Previous studies have shown that the increased prevalent ST764 clone in China, Japan, and other Asian areas. However, the knowledge of the genetic features and virulence characteristics of methicillin-resistant Staphylococcus aureus (MRSA) ST764 in China is still limited. In this study, we identified 52 ST764-SCCmec type II isolates collected from five cities in China between 2014 and 2021. Whole genome sequencing showed that the most common staphylococcal protein A (spa) types of ST764 in China were t002 (55.78%) and t1084 (40.38%). Virulence assays showed that ST764-t1084 isolates had high haemolytic activity and α-toxin levels. Of the critical regulatory factors affecting α-toxin production, only the SaeRS was highly expressed in ST764-t1084 isolates. Mouse abscess model indicated that the virulence of ST764-t1084 isolates was comparable to that of S. aureus USA300-LAC famous for its hypervirulence. Interestingly, ST764-t002 isolates exhibited stronger biofilm formation and cell adhesion capacities than ST764-t1084 isolates. This seems to explain why ST764-t002 subclone has become more prevalent in China in recent years. Phylogenetic analysis suggested that all ST764 isolates from China in Clade III were closely related to KUN1163 (an isolate from Japan). Notably, genomic analysis revealed that the 52 ST764 isolates did not carry arginine catabolic mobile element (ACME), which differed from ST764 isolates in Japan. Additionally, most ST764 isolates (69.23%) harboured an obvious deletion of approximately 5 kb in the SCCmec II cassette region compared to KUN1163. Our findings shed light on the potential global transmission and genotypic as well as phenotypic characteristics of ST764 lineage.


Asunto(s)
Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Animales , Ratones , Staphylococcus aureus Resistente a Meticilina/genética , Antibacterianos , Filogenia , Infecciones Estafilocócicas/epidemiología , Staphylococcus aureus , Virulencia , Genotipo , Factores de Virulencia/genética
15.
Chem Commun (Camb) ; 59(8): 1014-1017, 2023 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-36645064

RESUMEN

Acyl-homoserine lactone synthases make specific AHL quorum sensing signals to aid virulence in Gram-negative bacteria. Here, we use solution NMR spectroscopy to demonstrate that the carrier protein-enzyme interface accurately reveals substrate recognition mechanisms in two quorum signal synthases.


Asunto(s)
Proteínas Bacterianas , Proteínas Portadoras , Proteínas Portadoras/metabolismo , Proteínas Bacterianas/metabolismo , Bacterias Gramnegativas/metabolismo , Percepción de Quorum , Virulencia , Acil-Butirolactonas/química , Acil-Butirolactonas/metabolismo
16.
Sci Signal ; 16(767): eabm0488, 2023 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-36626577

RESUMEN

Escherichia coli are part of the normal intestinal microbiome, but some enterohemorrhagic E. coli (EHEC) and enteropathogenic E. coli (EPEC) strains can cause potentially life-threatening gastroenteritis. Virulence factors underlying the ability of EHEC and EPEC to cause disease include those encoded in the locus of the enterocyte effacement (LEE) pathogenicity island. Here, we demonstrated that EsrL, a small RNA present in many E. coli strains, promoted pathogenicity, adhesion, and biofilm formation in EHEC and EPEC. PhoB, the response regulator of the two-component system that controls cellular responses to phosphate, directly repressed esrL expression under low-phosphate conditions. A phosphate-rich environment, similar to that of the human intestine, relieved PhoB-mediated repression of esrL. EsrL interacted with and stabilized the LEE-encoded regulator (ler) transcript, which encodes a transcription factor for LEE genes, leading to increased bacterial adhesion to cultured cells and colonization of the rabbit colon. EsrL also bound to and stabilized the fimC transcript, which encodes a chaperone that is required for the assembly of type 1 pili, resulting in enhanced cell adhesion in pathogenic E. coli and enhanced biofilm formation in pathogenic and nonpathogenic E. coli. Our findings demonstrate that EsrL stimulates the expression of virulence genes in both EHEC and EPEC under phosphate-rich conditions, thus promoting the pathogenicity of EHEC and EPEC in the nutrient-rich gut environment.


Asunto(s)
Proteínas de Escherichia coli , Escherichia coli , Animales , Humanos , Conejos , Escherichia coli/genética , Escherichia coli/metabolismo , Virulencia/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Fosfatos/metabolismo , Biopelículas , Regulación Bacteriana de la Expresión Génica
17.
Artículo en Inglés | MEDLINE | ID: mdl-36674132

RESUMEN

This paper provides a snapshot on the pathogenic traits within CoNS isolated from ready-to-eat (RTE) food. Eighty-five strains were subjected to biofilm and slime production, as well as biofilm-associated genes (icaA, icaD, icaB, icaC, eno, bap, bhp, aap, fbe, embP and atlE), the insertion sequence elements IS256 and IS257 and hemolytic genes. The results showed that the most prevalent determinants responsible for the primary adherence were eno (57.6%) and aap (56.5%) genes. The icaADBC operon was detected in 45.9% of the tested strains and was correlated to slime production. Moreover, most strains carrying the icaADBC operon simultaneously carried the IS257 insertion sequence element. Among the genes encoding for surface proteins involved in the adhesion to abiotic surfaces process, atlE was the most commonly (31.8%) followed by bap (4.7%) and bhp (1.2%). The MSCRAMMs, including fbe and embp were detected in the 11.8% and 28.2% of strains, respectively. A high occurrence of genes involved in the hemolytic toxin production were detected, such as hla_yiD (50.6%), hlb (48.2%), hld (41.2%) and hla_haem (34.1%). The results of the present study revealed an unexpected occurrence of the genes involved in biofilm production and the high hemolytic activity among the CoNS strains, isolated from RTE food, highlighting that this group seems to be acquiring pathogenic traits similar to those of S. aureus, suggesting the need to be included in the routine microbiological analyses of food.


Asunto(s)
Coagulasa , Infecciones Estafilocócicas , Humanos , Coagulasa/genética , Staphylococcus aureus/genética , Virulencia , Infecciones Estafilocócicas/microbiología , Reacción en Cadena de la Polimerasa , Staphylococcus/genética , Biopelículas , Elementos Transponibles de ADN
18.
Int J Mol Sci ; 24(2)2023 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-36674496

RESUMEN

The matrix (M) protein of Newcastle disease virus (NDV) contains large numbers of unevenly distributed basic residues, but the precise function of most basic residues in the M protein remains enigmatic. We previously demonstrated that the C-terminus (aa 264-313) of M protein interacted with the extra-terminal (ET) domain of chicken bromodomain-containing protein 2 (chBRD2), which promoted NDV replication by downregulating chBRD2 expression and facilitating viral RNA synthesis and transcription. However, the key amino acid sites determining M's interaction with chBRD2/ET and their roles in the replication and pathogenicity of NDV are not known. In this study, three basic residues-R283, R286, and K288-in the NDV M protein were verified to be responsible for its interaction with chBRD2/ET. In addition, mutation of these basic residues (R283A/R286A/K288A) in the M protein changed its electrostatic pattern and abrogated the decreased expression of endogenic chBRD2. Moreover, a recombinant virus harboring these mutations resulted in a pathotype change of NDV and attenuated viral replication and pathogenicity in chickens due to the decreased viral RNA synthesis and transcription. Our findings therefore provide a better understanding of the crucial biological functions of M's basic residues and also aid in understanding the poorly understood pathogenesis of NDV.


Asunto(s)
Pollos , Virus de la Enfermedad de Newcastle , Animales , Virus de la Enfermedad de Newcastle/genética , Pollos/genética , Virulencia/genética , Mutación , Replicación Viral/genética , ARN Viral/metabolismo
19.
Int J Mol Sci ; 24(2)2023 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-36674786

RESUMEN

Pseudomonas aeruginosa is an opportunistic pathogen encoding several virulence factors in its genome, which is well-known for its ability to cause severe and life-threatening infections, particularly among cystic fibrosis patients. The organism is also a major cause of nosocomial infections, mainly affecting patients with immune deficiencies and burn wounds, ventilator-assisted patients, and patients affected by other malignancies. The extensively reported emergence of multidrug-resistant (MDR) P. aeruginosa strains poses additional challenges to the management of infections. The aim of this study was to compare the incidence rates of selected virulence-factor-encoding genes and the genotype distribution amongst clinical multidrug-sensitive (MDS) and MDR P. aeruginosa strains. The study involved 74 MDS and 57 MDR P. aeruginosa strains and the following virulence-factor-encoding genes: lasB, plC H, plC N, exoU, nan1, pilA, and pilB. The genotype distribution, with respect to the antimicrobial susceptibility profiles of the strains, was also analyzed. The lasB and plC N genes were present amongst several P. aeruginosa strains, including all the MDR P. aeruginosa, suggesting that their presence might be used as a marker for diagnostic purposes. A wide variety of genotype distributions were observed among the investigated isolates, with the MDS and MDR strains exhibiting, respectively, 18 and 9 distinct profiles. A higher prevalence of genes determining the virulence factors in the MDR strains was observed in this study, but more research is needed on the prevalence and expression levels of these genes in additional MDR strains.


Asunto(s)
Infecciones por Pseudomonas , Factores de Virulencia , Humanos , Factores de Virulencia/genética , Pseudomonas aeruginosa , Virulencia/genética , Farmacorresistencia Bacteriana Múltiple/genética , Antibacterianos/farmacología , Infecciones por Pseudomonas/epidemiología , Infecciones por Pseudomonas/tratamiento farmacológico , Genotipo , Pruebas de Sensibilidad Microbiana
20.
Int J Mol Sci ; 24(2)2023 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-36674895

RESUMEN

Calcium/calmodulin-dependent protein kinase (CaMK), a key downstream target protein in the Ca2+ signaling pathway of eukaryotes, plays an important regulatory role in the growth, development and pathogenicity of plant fungi. Three AaCaMKs (AaCaMK1, AaCaMK2 and AaCaMK3) with conserved PKC_like superfamily domains, ATP binding sites and ACT sites have been cloned from Alternaria alternata, However, their regulatory mechanism in A. alternata remains unclear. In this study, the function of the AaCaMKs in the development, infection structure differentiation and pathogenicity of A. alternata was elucidated through targeted gene disruption. The single disruption of AaCaMKs had no impact on the vegetative growth and spore morphology but significantly influenced hyphae growth, sporulation, biomass accumulation and melanin biosynthesis. Further expression analysis revealed that the AaCaMKs were up-regulated during the infection structure differentiation of A. alternata on hydrophobic and pear wax substrates. In vitro and in vivo analysis further revealed that the deletion of a single AaCaMKs gene significantly reduced the A. alternata conidial germination, appressorium formation and infection hyphae formation. In addition, pharmacological analysis confirmed that the CaMK specific inhibitor, KN93, inhibited conidial germination and appressorium formation in A. alternata. Meanwhile, the AaCaMKs genes deficiency significantly reduced the A. alternata pathogenicity. These results demonstrate that AaCaMKs regulate the development, infection structure differentiation and pathogenicity of A. alternata and provide potential targets for new effective fungicides.


Asunto(s)
Fungicidas Industriales , Pyrus , Pyrus/microbiología , Virulencia/genética , Alternaria , Fungicidas Industriales/farmacología , Fungicidas Industriales/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...