Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 9.870
Filtrar
1.
J Appl Microbiol ; 130(1): 265-277, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32619289

RESUMEN

AIMS: Relatively, few anti-biofilm polysaccharides against Pseudomonas aeruginosa were done to investigate the underlying molecular mechanism. Exopolysaccharide EPS273 can clearly reduce biofilm formation and infection of P. aeruginosa. This study aims to investigate its anti-biofilm and anti-infection mechanism on transcriptional level. METHODS AND RESULTS: Herein, we used an RNA-Seq transcriptomic approach to investigate the underlying anti-biofilm and anti-infection mechanism of EPS273. The expression levels of a large number of genes were changed after P. aeruginosa PAO1 was treated with EPS273. Especially, the genes related to biofilm formation, such as gene involved in production of extracellular matrix and virulence factor, genes involved in flagella and cell motility and genes involved in iron acquisition. Notably, the expression levels of genes involved in regulatory and signal transduction were markedly downregulated, such as two-component system PhoP-PhoQ and quorum sensing (QS) system LasI/LasR and RhlI/RhlR. Furthermore, when genes phoP and phoQ were disrupted, respectively, the reduction of biofilm formation and cell motility in mutant △phoP or △phoQ was also detected. CONCLUSION: EPS273 may exert its anti-biofilm and anti-infection function by downregulating gene expression of two-component system PhoP-PhoQ and QS systems LasI/LasR and RhlI/RhlR of P. aeruginosa, which further regulated expression of genes involved in biofilm formation. SIGNIFICANCE AND IMPACT OF THE STUDY: Our data will expand understanding of anti-biofilm mechanisms of polysaccharides on transcriptomic level.


Asunto(s)
Antibacterianos/farmacología , Biopelículas/efectos de los fármacos , Polisacáridos/farmacología , Pseudomonas aeruginosa/efectos de los fármacos , Transcriptoma/efectos de los fármacos , Proteínas Bacterianas/genética , Biopelículas/crecimiento & desarrollo , Matriz Extracelular/efectos de los fármacos , Matriz Extracelular/genética , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Pseudomonas aeruginosa/fisiología , Percepción de Quorum/efectos de los fármacos , Percepción de Quorum/genética , Factores de Virulencia/genética
2.
Odontology ; 109(1): 18-28, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32279229

RESUMEN

Porphyromonas gingivalis is a keystone pathogen and major colonizer in host tissue which plays a pivotal role in periodontitis among the other polymicrobial infections. Increasing facts demonstrate that curcumin has antibacterial activity and anti-biofilm effect against the periodontopathogens through diverse mechanisms that have a positive impact on periodontal health. The present study was aimed to elucidate the effect of curcumin on biofilm formation and virulence factor gene expression of P. gingivalis. By using gene expression studies, we exploited the mechanism of anti-biofilm effects of curcumin on P. gingivalis. The minimum inhibitory concentration and minimum bactericidal concentration of curcumin for both ATCC and clinical strains of P. gingivalis were found to be 62.5 and 125 µg ml-1 respectively. Curcumin prevented bacterial adhesion and biofilm formation in a dose-dependent manner. Further, curcumin attenuated the virulence of P. gingivalis by reducing the expression of genes coding for major virulence factors, including adhesions (fimA, hagA, and hagB) and proteinases (rgpA, rgpB, and kgp). The results indicated that curcumin has shown anti-biofilm as well as antibacterial activity against P. gingivalis. Further, curcumin because of its pleiotropic actions could be a simple and inexpensive therapeutic strategy in the treatment of periodontal disease.


Asunto(s)
Curcumina , Porphyromonas gingivalis , Adhesinas Bacterianas/genética , Biopelículas , Curcumina/farmacología , Expresión Génica , Factores de Virulencia/genética
3.
BMC Infect Dis ; 20(1): 909, 2020 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-33261585

RESUMEN

BACKGROUND: The objective of this study was to evaluate the virulence of P. aeruginosa ventilator-associated pneumonia (VAP) strains (cases) in terms of biofilm production and other phenotypic and genotypic virulence factors compared to P. aeruginosa strains isolated from other infections (controls). METHODS: Biofilm production was tested to assess biomass production and metabolic activity using crystal violet binding assay and XTT assay, respectively. Pigment production (pyocyanin and pyoverdine) was evaluated using cetrimide agar. Virulence genes were detected by conventional multiplex PCR and virulence was tested in an in vivo model in Galleria mellonella larvae. RESULTS: We did not find statistically significant differences between VAP and no-VAP strains (p > 0.05) regarding biofilm production. VAP strains had no production of pyocyanin after 24 h of incubation (p = 0.023). The distribution of virulence genes between both groups were similar (p > 0.05). VAP strains were less virulent than non-VAP strains in an in vivo model of G. mellonella (p < 0.001). CONCLUSION: The virulence of VAP-Pseudomonas aeruginosa does not depend on biofilm formation, production of pyoverdine or the presence of some virulence genes compared to P. aeruginosa isolated from non-invasive locations. However, VAP strains showed attenuated virulence compared to non-VAP strains in an in vivo model of G. mellonella.


Asunto(s)
Neumonía Asociada al Ventilador/microbiología , Infecciones por Pseudomonas/microbiología , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/patogenicidad , Biopelículas , Genotipo , Humanos , Reacción en Cadena de la Polimerasa Multiplex , Oligopéptidos/metabolismo , Fenotipo , Pseudomonas aeruginosa/metabolismo , Piocianina/metabolismo , Ventiladores Mecánicos/efectos adversos , Virulencia/genética , Factores de Virulencia/genética
4.
PLoS One ; 15(12): e0235583, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33320853

RESUMEN

BACKGROUND: Escherichia coli O157 is an emerging foodborne pathogen of great public health concern. It has been associated with bloody diarrhoea, haemorrhagic colitis and haemolytic uremic syndrome in humans. Most human infections have been traced to cattle and the consumption of contaminated cattle products. In order to understand the risk associated with the consumption of cattle products, this study sought to investigate the prevalence and identify virulence genes in E. coli O157 from cattle in Cameroon. METHOD: A total of 512 rectal samples were obtained and analysed using conventional bacteriological methods (enrichment on modified Tryptone Soy Broth and selective plating on Cefixime-Tellurite Sorbitol Mac-Conkey Agar) for the isolation of E. coli O157. Presumptive E. coli O157 isolates were confirmed serologically using E. COLIPROTM O157 latex agglutination test and molecularly using PCR targeting the rfb gene in the isolates. Characterisation of the confirmed E. coli O157 strains was done by amplification of stx1, stx2, eaeA and hlyA virulence genes using both singleplex and multiplex PCR. RESULTS: E. coli O157 was detected in 56 (10.9%) of the 512 samples examined. The presence of the virulence genes stx2, eaeA and hylA was demonstrated in 96.4% (54/56) of the isolates and stx1 in 40 (71.4%) of the 54. The isolates exhibited three genetic profiles (I-III) with I (stx1, stx2, eaeA and hlyA) being the most prevalent (40/56; 71.4%) while two isolates had none of the virulence genes tested. CONCLUSION: A proportion of cattle slaughtered in abattoirs in Buea are infected with pathogenic E. coli O157 and could be a potential source of human infections. We recommend proper animal food processing measures and proper hygiene be prescribed and implemented to reduce the risk of beef contamination.


Asunto(s)
Infecciones por Escherichia coli/microbiología , Escherichia coli O157/genética , Factores de Virulencia/genética , Virulencia/genética , Animales , Camerún , Bovinos , Proteínas de Escherichia coli/genética , Microbiología de Alimentos/métodos , Perfil Genético , Carne/microbiología , Reacción en Cadena de la Polimerasa/métodos , Prevalencia
5.
PLoS One ; 15(12): e0239107, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33320859

RESUMEN

Avian Pathogenic Escherichia coli (APEC) cause colibacillosis leading to significant economic losses in the poultry industry. This laboratory-based study aimed at establishing stocks of avian pathogenic Escherichia coli lytic bacteriophages, for future development of cocktail products for colibacillosis management. The study determined the antibiotic susceptibility; phylogenetic categories, occurrence of selected serotypes and virulence genes among Escherichia coli stock isolates from chicken colibacillosis cases; and evaluated bacteriophage activity against the bacteria. Escherichia coli characterization was done through phenotypic and multiplex PCR methods. Bacteriophage isolation and preliminary characterization was achieved using the spot assay and overlay plating techniques. Fifty-six (56) isolates were phenotypically confirmed as E. coli and all exhibited resistance to at least one antimicrobial agent; while multi-drug resistance (at least three drugs) was encountered in 50 (89.3%) isolates. The APEC isolates mainly belonged to phylogroups A and D, representing 44.6% and 39.3%, respectively; whereas serotypes O1, O2 and O78 were not detected. Of the 56 isolates, 69.6% harbored at least one virulence gene, while 50% had at least four virulence genes; hence confirmed as APEC. Virulence genes, ompT and iutA were the most frequent in 33 (58.9%) and 32 (57.1%) isolates respectively; while iroN least occurred in 23 (41.1%) isolates. Seven lytic bacteriophages were isolated and their host range, at 1×108 PFU/ml, varied from 1.8% to 17.9% of the 56 APEC isolates, while the combined lytic spectrum was 25%. Phage stability was negatively affected by increasing temperatures with both UPEC04 and UPEC10 phages being undetectable at 70°C; whereas activity was detected between pH 2 and 12. The high occurrence of APEC isolates resistant against the commonly used antibiotics supports the need for alternative strategies of bacterial infections control in poultry. The low host range exhibited by the phages necessitates search for more candidates before in-depth phage characterization and application.


Asunto(s)
Bacteriófagos/genética , Infecciones por Escherichia coli/virología , Escherichia coli/virología , Enfermedades de las Aves de Corral/virología , Animales , Antibacterianos/farmacología , Pollos/microbiología , Pollos/virología , Colifagos/genética , Escherichia coli/efectos de los fármacos , Proteínas de Escherichia coli/genética , Filogenia , Uganda , Virulencia/genética , Factores de Virulencia/genética
6.
Nat Commun ; 11(1): 6246, 2020 12 07.
Artículo en Inglés | MEDLINE | ID: mdl-33288753

RESUMEN

Vibrio cholerae is an aquatic microbe that can be divided into three subtypes: harmless environmental strains, localised pathogenic strains, and pandemic strains causing global cholera outbreaks. Each type has a contact-dependent type VI secretion system (T6SS) that kills neighbouring competitors by translocating unique toxic effector proteins. Pandemic isolates possess identical effectors, indicating that T6SS effectors may affect pandemicity. Here, we show that one of the T6SS gene clusters (Aux3) exists in two states: a mobile, prophage-like element in a small subset of environmental strains, and a truncated Aux3 unique to and conserved in pandemic isolates. Environmental Aux3 can be readily excised from and integrated into the genome via site-specific recombination, whereas pandemic Aux3 recombination is reduced. Our data suggest that environmental Aux3 acquisition conferred increased competitive fitness to pre-pandemic V. cholerae, leading to grounding of the element in the chromosome and propagation throughout the pandemic clade.


Asunto(s)
Proteínas Bacterianas/genética , Recombinación Genética , Sistemas de Secreción Tipo VI/genética , Vibrio cholerae/genética , Factores de Virulencia/genética , Proteínas Bacterianas/clasificación , Proteínas Bacterianas/metabolismo , Secuencia de Bases , Cólera/epidemiología , Cólera/microbiología , Humanos , Modelos Genéticos , Familia de Multigenes , Pandemias , Filogenia , Homología de Secuencia de Ácido Nucleico , Sistemas de Secreción Tipo VI/metabolismo , Vibrio cholerae/clasificación , Vibrio cholerae/patogenicidad , Virulencia/genética , Factores de Virulencia/metabolismo
7.
Mem Inst Oswaldo Cruz ; 115: e200370, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33174903

RESUMEN

BACKGROUND: Bacillus anthracis is the aetiologic agent of anthrax, a re-emerging, septicaemic, haemorrhagic and lethal disease that affects humans, domestic ruminants and wildlife. Plasmids pXO1 and pXO2 are attributes that confer pathogenicity to B. anthracis strains. This bacterium was used as biological weapon in the World Wars and in the biological attack in the United States of America at 2001. B. anthracis is classified as a Tier 1 bioterrorism agent by the Centers for Diseases Control and Prevention. Anthrax is recognised as a re-emerging disease. Several studies concerning the dynamics of B. anthracis cycle in soil revealed that nonpathogenic B. anthracis strains due to lack of pXO2 plasmid are commonly found in some types of soil. OBJECTIVES: This study aimed isolation and identification of B. anthracis spores in soil samples of the state of Rio de Janeiro, Brazil. METHODS: Phenotypic and genotypic approaches were used to identify isolates including MALDI-TOF/MS, motility test, susceptibility to gamma phage and penicillin, survey for pag and cap genes as surrogates of pXO1 and pXO2 plasmids, respectively, and sequencing of 16SrRNA-encoding gene. Physicochemical analysis of the soil samples were carried out to describe soil characteristics. FINDINGS: We observed the presence of one B. anthracis pXO1+ and pXO2- isolated from clay loam soil; one B. anthracis-like strain pXO1+ and pXO2-isolated from loamy sand; and 10 Bacillus spp. strains sensitive to phage-gamma that need better characterisation to define which their species were recovered from loamy sand. MAIN CONCLUSIONS: This work showed promising results and it was the first study to report results from an active surveillance for B. anthracis in Brazil.


Asunto(s)
Bacillus anthracis/aislamiento & purificación , ADN Bacteriano/genética , Plásmidos/análisis , Reacción en Cadena de la Polimerasa/métodos , Microbiología del Suelo , Esporas Bacterianas , Factores de Virulencia/genética , Antígenos Bacterianos , Bacillus anthracis/genética , Bacillus anthracis/patogenicidad , Toxinas Bacterianas , Brasil , ADN Bacteriano/análisis , Humanos , Plásmidos/genética , Análisis de Secuencia de ADN , Suelo , Virulencia
8.
Front Immunol ; 11: 582102, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33193390

RESUMEN

The suppressor of cytokine signaling (SOCS) family of intracellular checkpoint inhibitors has received little recognition compared to other checkpoint inhibitors. Two members of this family, SOCS1 and SOCS3, are indispensable, since SOCS1 knockout in mice results in neonatal death due to interferon gamma (IFNγ) induced inflammatory disease, and SOCS3 knockout leads to embryonic lethality. We have shown that SOCS1 and SOCS3 (SOCS1/3) function as virus induced intrinsic virulence factors for influenza A virus, EMC virus, herpes simplex virus 1 (HSV-1), and vaccinia virus infections. Other viruses such as pathogenic pig enteric coronavirus and coronavirus induced severe acute respiratory syndrome (SARS) spike protein also induce SOCS virus intrinsic virulence factors. SOCS1/3 exert their viral virulence effect via inhibition of type I and type II interferon (IFN) function. Specifically, the SOCS bind to the activation loop of receptor-associated tyrosine kinases JAK2 and TYK2 through the SOCS kinase inhibitory region (KIR), which inhibits STAT transcription factor activation by the kinases. Activated STATs are required for IFN function. We have developed a small peptide antagonist of SOCS1/3 that blocks SOCS1/3 inhibitory activity and prevents virus pathogenesis. The antagonist, pJAK2(1001-1013), is comprised of the JAK2 activation loop, phosphorylated at tyrosine 1007 with a palmitate for cell penetration. The remarkable thing about SOCS1/3 is that it serves as a broad, simple tool of perhaps most pathogenic viruses to avoid innate host IFN defense. We suggest in this Perspective that SOCS1/3 antagonist is a simple counter measure to SOCS1/3 and should be an effective mechanism as a prophylactic and/or therapeutic against the COVID-19 pandemic that is caused by coronavirus SARS-CoV2.


Asunto(s)
/tratamiento farmacológico , /fisiología , Proteína 1 Supresora de la Señalización de Citocinas/inmunología , Proteína 3 Supresora de la Señalización de Citocinas/inmunología , Factores de Virulencia/inmunología , Animales , /virología , Humanos , Interferones/genética , Interferones/inmunología , Ratones , Proteína 1 Supresora de la Señalización de Citocinas/genética , Proteína 3 Supresora de la Señalización de Citocinas/genética , Factores de Virulencia/genética
9.
Nat Commun ; 11(1): 5968, 2020 11 24.
Artículo en Inglés | MEDLINE | ID: mdl-33235212

RESUMEN

Escherichia coli is the leading cause of urinary tract infection, one of the most common bacterial infections in humans. Despite this, a genomic perspective is lacking regarding the phylogenetic distribution of isolates associated with different clinical syndromes. Here, we present a large-scale phylogenomic analysis of a spatiotemporally and clinically diverse set of 907 E. coli isolates, including 722 uropathogenic E. coli (UPEC) isolates. A genome-wide association approach identifies the (P-fimbriae-encoding) papGII locus as the key feature distinguishing invasive UPEC, defined as isolates associated with severe UTI, i.e., kidney infection (pyelonephritis) or urinary-source bacteremia, from non-invasive UPEC, defined as isolates associated with asymptomatic bacteriuria or bladder infection (cystitis). Within the E. coli population, distinct invasive UPEC lineages emerged through repeated horizontal acquisition of diverse papGII-containing pathogenicity islands. Our findings elucidate the molecular determinants of severe UTI and have implications for the early detection of this pathogen.


Asunto(s)
Adhesinas de Escherichia coli/genética , Transferencia de Gen Horizontal/genética , Islas Genómicas/genética , Escherichia coli Uropatógena , ADN Bacteriano/genética , Infecciones por Escherichia coli/microbiología , Fimbrias Bacterianas/genética , Genoma Bacteriano , Estudio de Asociación del Genoma Completo , Humanos , Filogenia , Sistema Urinario/microbiología , Infecciones Urinarias/microbiología , Escherichia coli Uropatógena/genética , Escherichia coli Uropatógena/patogenicidad , Factores de Virulencia/genética
10.
Parasitol Res ; 119(11): 3803-3815, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33006041

RESUMEN

Trypanosoma cruzi is the etiological agent of Chagas disease, whose clinical outcome ranges from asymptomatic individuals to chronic fatal megasyndromes. Despite being central to pathogenesis, the regulation of parasite virulence factors' expression remains largely unknown. In this work, the relative expression of several parasite virulence factors between two TcI strains (Ninoa, low virulence and Qro, high virulence) was assessed by qRT-PCR of total and of polysome-associated mRNA, as well as by western blots. Trypomastigotes were also incubated with specific anti-sense morpholino oligonucleotides to block the translation of a selected virulence factor, calreticulin, in both strains. Ninoa trypomastigotes showed significantly lower levels of trypomastigote-decay acceleration factor, complement regulatory protein, complement C2 receptor inhibitor trispanning, and glycoproteins 82 and 90 mRNAs compared with Qro. There was a significantly lower recruitment of complement regulatory protein and complement C2 receptor inhibitor trispanning mRNAs to polysomes and higher recruitment of MASP mRNA to monosomes in Ninoa strain. Calreticulin mRNA displayed both a higher total mRNA level and recruitment to translationally active polysomes in the Ninoa strain (low virulence) than in the Qro strain (high virulence). When calreticulin was downregulated by ≈ 50% by anti-sense morpholino oligonucleotides, a significant decrease of parasite invasion in mammalian cells was found in both strains. Calreticulin downregulation, however, only increased significantly the activation of the complement system by Ninoa trypomastigotes. These results suggest a role for the regulation of virulence factors' gene expression in the differential virulence among T. cruzi strains. Furthermore, a possible function of calreticulin in parasite invasion not related to its binding to complement factors is shown.


Asunto(s)
Regulación de la Expresión Génica , Genes Protozoarios/genética , Trypanosoma cruzi/genética , Trypanosoma cruzi/patogenicidad , Factores de Virulencia/genética , Virulencia/genética , Animales , Western Blotting , Calreticulina/genética , Enfermedad de Chagas/parasitología , Chlorocebus aethiops , Cobayas , ARN Mensajero/metabolismo , Células Vero
11.
PLoS One ; 15(10): e0240834, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33075055

RESUMEN

Bacterial "stand-alone" response regulators (RRs) are pivotal to the control of gene transcription in response to changing cytosolic and extracellular microenvironments during infection. The genome of group A Streptococcus (GAS) encodes more than 30 stand-alone RRs that orchestrate the expression of virulence factors involved in infecting multiple tissues, so causing an array of potentially lethal human diseases. Here, we analysed the molecular epidemiology and biological associations in the coding sequences (CDSs) and upstream intergenic regions (IGRs) of 35 stand-alone RRs from a collection of global GAS genomes. Of the 944 genomes analysed, 97% encoded 32 or more of the 35 tested RRs. The length of RR CDSs ranged from 297 to 1587 nucleotides with an average nucleotide diversity (π) of 0.012, while the IGRs ranged from 51 to 666 nucleotides with average π of 0.017. We present new evidence of recombination in multiple RRs including mga, leading to mga-2 switching, emm-switching and emm-like gene chimerization, and the first instance of an isolate that encodes both mga-1 and mga-2. Recombination was also evident in rofA/nra and msmR loci with 15 emm-types represented in multiple FCT (fibronectin-binding, collagen-binding, T-antigen)-types, including novel emm-type/FCT-type pairings. Strong associations were observed between concatenated RR allele types, and emm-type, MLST-type, core genome phylogroup, and country of sampling. No strong associations were observed between individual loci and disease outcome. We propose that 11 RRs may form part of future refinement of GAS typing systems that reflect core genome evolutionary associations. This subgenomic analysis revealed allelic traits that were informative to the biological function, GAS strain definition, and regional outbreak detection.


Asunto(s)
Regulación Bacteriana de la Expresión Génica/genética , Streptococcus pyogenes/genética , Streptococcus pyogenes/metabolismo , Antígenos Bacterianos/genética , Proteínas de la Membrana Bacteriana Externa/genética , Proteínas Bacterianas/genética , Proteínas Portadoras/metabolismo , Simulación por Computador , ADN Bacteriano/genética , ADN Intergénico/metabolismo , Infecciones Estreptocócicas/genética , Factores de Virulencia/genética
12.
Sci Rep ; 10(1): 17108, 2020 10 13.
Artículo en Inglés | MEDLINE | ID: mdl-33051473

RESUMEN

Processing of animal carcasses and other animal wastes in rendering plants is a significant source of antibiotic resistant microorganisms. The main goal of this study was to investigate the resistance to 18 antibacterial agents including ß-lactams, fluoroquinolones, colistin and virulence factors (iss, tsh, cvaC, iutA, papC, kps and ibeA genes) in 88 Escherichia coli strains isolated from a rendering plant over 1 year period. ESBL (Extended-spectrum beta-lactamases) and plasmid-mediated Amp were screened by interpretative reading of MIC. ESBL phenotype was detected in 20.4% of samples and high level of resistance to fluoroquinolone was found in 27.2% of strains. Cephalosporinase CTX-M1, cephamycinase CMY-2, integrase 1 and transposon 3 genes were detected by PCR. Furthermore, there were found three CMY-2 producing E. coli with O25b-ST131, resistant to the high level of enrofloxacin and containing the gene encoding the ferric aerobactin receptor (iutA). One enrofloxacin resistant E. coli strain possessed iss, ibeA, kps and papC virulence genes also with CMY-2, integrase1 and Tn3. ST131 E. coli with CMY-2 has a zoonotic potential and presents a serious health risk to humans.


Asunto(s)
Farmacorresistencia Bacteriana , Escherichia coli/efectos de los fármacos , Industria para Empaquetado de Carne , Animales , Antibacterianos/farmacología , Escherichia coli/genética , Escherichia coli/aislamiento & purificación , Escherichia coli/patogenicidad , Pruebas de Sensibilidad Microbiana , Reacción en Cadena de la Polimerasa , Virulencia/genética , Factores de Virulencia/genética , Resistencia betalactámica
13.
PLoS Pathog ; 16(10): e1008917, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-33017449

RESUMEN

Babesia bovis causes a pathogenic form of babesiosis in cattle. Following invasion of red blood cells (RBCs) the parasite extensively modifies host cell structural and mechanical properties via the export of numerous proteins. Despite their crucial role in virulence and pathogenesis, such proteins have not been comprehensively characterized in B. bovis. Here we describe the surface biotinylation of infected RBCs (iRBCs), followed by proteomic analysis. We describe a multigene family (mtm) that encodes predicted multi-transmembrane integral membrane proteins which are exported and expressed on the surface of iRBCs. One mtm gene was downregulated in blasticidin-S (BS) resistant parasites, suggesting an association with BS uptake. Induced knockdown of a novel exported protein encoded by BBOV_III004280, named VESA export-associated protein (BbVEAP), resulted in a decreased growth rate, reduced RBC surface ridge numbers, mis-localized VESA1, and abrogated cytoadhesion to endothelial cells, suggesting that BbVEAP is a novel virulence factor for B. bovis.


Asunto(s)
Babesia bovis/patogenicidad , Babesiosis/parasitología , Células Endoteliales/parasitología , Eritrocitos/parasitología , Animales , Babesia bovis/genética , Bovinos , Enfermedades de los Bovinos/parasitología , Proteínas de la Membrana , Parásitos/patogenicidad , Proteómica/métodos , Factores de Virulencia/genética
14.
PLoS One ; 15(10): e0239924, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33036018

RESUMEN

The prevalence of carbapenem-resistant Enterobacterales (CRE) in the Arabian Peninsula is predicted to be high, as suggested from published case reports. Of particular concern, is carbapenem-resistant E. coli (CR-EC), due to the importance of this species as a community pathogen. Herein, we conducted a comprehensive molecular characterization of putative CR-EC strains from Oman. We aim to establish a baseline for future molecular monitoring. We performed whole-genome sequencing (WGS) for 35 putative CR-EC. Isolates were obtained from patients at multiple centers in 2015. Genetic relatedness was investigated using several typing approaches such as MLST, SNP calling, phylogroup and CRISPR typing. Maxiuium likelihood SNP-tree was performed by RAxML after variant calling and removal of recombination regions with Snippy and Gubbins, respectively. Resistance genes, plasmid replicon types, virulence genes, and prophage were also characterised. The online databases CGE, CRISPRcasFinder, Phaster and EnteroBase were used for the in silico analyses. Screening for mutations in genes regulating the expression of porins and efflux pump as well as mutations lead to fluoroquinolones resistance were performed with CLC Genomics Workbench. The genetic diversity suggests a polyclonal population structure with 21 sequence types (ST), of which ST38 being the most prevalent (11%). SNPs analysis revealed possible transmission episodes. Whereas, CRISPR typing helped to spot outlier strains belonged to phylogroups other than B2 which was CRISPR-free. The virulent phylogroups B2 and D were detected in 4 and 9 isolates, respectively. In some strains bacteriophages acted as vectors for virulence genes. Regarding resistance to ß-lactam, 22 were carbapenemase producers, 3 carbapenem non-susceptible but carbapenemase-negative, 9 resistant to expanded-spectrum cephalosporins, and one isolate with susceptibility to cephalosporins and carbapenems. Thirteen out of the 22 (59%) carbapenemase-producing isolates were NDM and 7 (23%) were OXA-48-like which mirrors the situation in Indian subcontinent. Two isolates co-produced NDM and OXA-48-like enzymes. In total, 80% (28/35) were CTX-M-15 producers and 23% (8/35) featured AmpC. The high-risk subclones ST131-H30Rx/C2, ST410-H24RxC and ST1193-H64RxC were detected, the latter associated with NDM. To our knowledge, this is the first report of ST1193-H64Rx subclone with NDM. In conclusion, strains showed polyclonal population structure with OXA-48 and NDM as the only carbapenemases in CR-EC from Oman. We detected the high-risk subclone ST131-H30Rx/C2, ST410-H24RxC and ST1193-H64RxC. The latter was reported with carbapenemase gene for the first time here.


Asunto(s)
Carbapenémicos/farmacología , Infecciones por Escherichia coli , Proteínas de Escherichia coli/genética , Escherichia coli , Resistencia betalactámica/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Bases de Datos Genéticas , Escherichia coli/clasificación , Escherichia coli/efectos de los fármacos , Escherichia coli/aislamiento & purificación , Infecciones por Escherichia coli/epidemiología , Infecciones por Escherichia coli/microbiología , Femenino , Genes Bacterianos , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Omán , Plásmidos , Factores de Virulencia/genética , Adulto Joven
15.
PLoS One ; 15(10): e0240978, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33125394

RESUMEN

International lineages, such as Salmonella Typhimurium sequence type (ST) 19, are most often associated with foodborne diseases and deaths in humans. In this study, we compared the whole-genome sequences of five S. Typhimurium strains belonging to ST19 recovered from clinical human stool samples in North Carolina, United States. Overall, S. Typhimurium strains displayed multidrug-resistant profile, being resistance to critically and highly important antimicrobials including ampicillin, ticarcillin/clavulanic acid, streptomycin and sulfisoxazole, chloramphenicol, tetracycline, respectively. Interestingly, all S. Typhimurium strains carried class 1 integron (intl1) and we were able to describe two genomic regions surrounding blaCARB-2 gene, size 4,062 bp and 4,422 bp for S. Typhimurium strains (HS5344, HS5437, and HS5478) and (HS5302 and HS5368), respectively. Genomic analysis for antimicrobial resistome confirmed the presence of clinically important genes, including blaCARB-2, aac(6')-Iaa, aadA2b, sul1, tetG, floR, and biocide resistance genes (qacEΔ1). S. Typhimurium strains harbored IncFIB plasmid containing spvRABCD operon, as well as rck and pef virulence genes, which constitute an important apparatus for spreading the virulence plasmid. In addition, we identified several virulence genes, chromosomally located, while the phylogenetic analysis revealed clonal relatedness among these strains with S. enterica isolated from human and non-human sources obtained in European and Asian countries. Our results provide new insights into this unusual class 1 integron in virulent S. Typhimurium strains that harbors a pool of genes acting as potential hotspots for horizontal gene transfer providing readily adaptation to new surrounds, as well as being crucially required for virulence in vivo. Therefore, continuous genomic surveillance is an important tool for safeguarding human health.


Asunto(s)
Farmacorresistencia Bacteriana Múltiple , Infecciones por Salmonella/microbiología , Salmonella typhimurium/clasificación , Factores de Virulencia/genética , beta-Lactamasas/genética , Antibacterianos/farmacología , Genoma Bacteriano , Humanos , Integrones , Pruebas de Sensibilidad Microbiana , Filogenia , Plásmidos/genética , Salmonella typhimurium/genética , Salmonella typhimurium/aislamiento & purificación , Salmonella typhimurium/patogenicidad , Estados Unidos , Secuenciación Completa del Genoma
16.
Acta Odontol Latinoam ; 33(2): 104-111, 2020 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-32920612

RESUMEN

Candida dubliniensis (Cd) and Candida albicans (Ca) are the most frequently isolated yeasts in HIV+ patients. Some of the enzymes produced by these yeasts are considered virulence factors since they contribute to pathogenicity of Candida spp. The aim of the present study was to compare production of enzymes such as phospholipase (Ph), proteinase (P), and hemolysin (H) by Cd and Ca strains isolated from periodontal HIV-positive patients receiving and not receiving highly active antiretroviral therapy (HAART). Subgingival biofilm samples were obtained using paper points, and a sample of oral mucosa was taken using a swab. Phenotypic and molecular methods were used to isolate 39 strains of Candida, including 25 strains of Cd and 14 strains of Ca, obtained from 33 periodontal pocket samples and 6 oral mucosa samples collected from 15 HIV+ patients (8 receiving and 7 not receiving HAART). Malt egg-yolk agar, albumin agar and blood agar were used to evaluate pH, P and H production respectively. The strains were inoculated in duplicate and incubated at 37 ºC. Colony and halo diameters were measured. A greater proportion of Ca was observed in patients not receiving HAART, and a higher proportion of Cd was observed in those under HAART, Chi2 p< 0.001. Phospholipase production was observed in 92.9% percent of isolated Ca strains but in none of the isolated Cd strains. Proteinase production was high in Ca and Cd strains isolated from patients not receiving HAART. Hemolysin production was observed in all the studied strains, though it was significantly higher (p=0.04) in Ca and Cd strains isolated from patients not receiving HAART. To sum up, the proportion of Candida dubliniensis strains was highest in the subgingival biofilm of patients receiving HAART, and Cd strains were found to express fewer virulence factors than Ca strains.


Asunto(s)
Terapia Antirretroviral Altamente Activa/métodos , Biopelículas/crecimiento & desarrollo , Candida albicans/enzimología , Candida albicans/aislamiento & purificación , Candida/enzimología , Candida/aislamiento & purificación , Candidiasis Bucal/microbiología , Encía/microbiología , Infecciones por VIH/complicaciones , Candida/clasificación , Candida/genética , Candida albicans/genética , Candidiasis Bucal/complicaciones , Genotipo , Infecciones por VIH/microbiología , Humanos , Mucosa Bucal/microbiología , Fenotipo , Reacción en Cadena de la Polimerasa , Factores de Virulencia/genética
17.
Int J Food Microbiol ; 335: 108852, 2020 Dec 16.
Artículo en Inglés | MEDLINE | ID: mdl-32932210

RESUMEN

Bagged, pre-cut and prewashed lettuce products are marketed as ready to eat. This concept poses a food safety concern, due to lack of efficient hurdles to eliminate possible microbial contaminants from the fresh produce and/or the processing itself. Aeromonas spp. are potential foodborne pathogens that are frequently isolated from lettuce. High counts of, e.g., A. hydrophila have been found in retail ready-to-eat (RTE) vegetable salads. The aim of this study was to assess the general microbiological quality, the occurrence and diversity of potential human pathogenic mesophilic Aeromonas spp. of retail RTE lettuce products. Additionally, temperature-dependent growth kinetic parameters of Aerobic Plate Counts (APC) and Aeromonas spp. in one selected RTE lettuce product, rocket lettuce, were quantified by performing storage experiments at 4 °C, 8 °C and 12 °C. The Aeromonas isolates were further characterized regarding pathogenic traits and phylogenetic relationship. The overall hygienic quality of the lettuce products was unsatisfactory, as 60% of the products had an APC level higher than 7.0 log CFU/g. Presumptive Aeromonas spp. were detected in 52% of the samples, levels ranging from approximately 2.0-6.0 log CFU/g. Significantly lower counts of APC and Aeromonas spp. were found in uncut and unwashed products. Presumptive Aeromonas spp. were able to proliferate in rocket lettuce stored at 4 °C (µmax = 0.39 ± 0.06/d and µmax = 0.43 ± 0.05/d for lettuce from producers A and B, respectively), and µmax was approximately 2× higher at 8 °C and 3× higher at 12 °C. Eighty-four percent of the collected isolates were identified as A. media, based on partial gyrB sequencing. Additionally A. salmonicida and A. bestiarum were detected. The pathogenic potential in this material was high, most of the isolates harbored at least one of the toxin genes, act, ast, alt.


Asunto(s)
Aeromonas/crecimiento & desarrollo , Lechuga/microbiología , Temperatura , Verduras/microbiología , Aeromonas/clasificación , Aeromonas/aislamiento & purificación , Recuento de Colonia Microbiana , Comida Rápida/microbiología , Contaminación de Alimentos , Microbiología de Alimentos , Almacenamiento de Alimentos , Noruega , Filogenia , Factores de Virulencia/genética
18.
PLoS Genet ; 16(9): e1008744, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32956370

RESUMEN

Qsp1 is a secreted quorum sensing peptide required for virulence of the fungal meningitis pathogen Cryptococcus neoformans. Qsp1 functions to control cell wall integrity in vegetatively growing cells and also functions in mating. Rather than acting on a cell surface receptor, Qsp1 is imported to act intracellularly via the predicted oligopeptide transporter Opt1. Here, we identify a transcription factor network as a target of Qsp1. Using whole-genome chromatin immunoprecipitation, we find Qsp1 controls the genomic associations of three transcription factors to genes whose outputs are regulated by Qsp1. One of these transcription factors, Cqs2, is also required for the action of Qsp1 during mating, indicating that it might be a shared proximal target of Qsp1. Consistent with this hypothesis, deletion of CQS2 impacts the binding of other network transcription factors specifically to Qsp1-regulated genes. These genetic and genomic studies illuminate mechanisms by which an imported peptide acts to modulate eukaryotic gene expression.


Asunto(s)
Cryptococcus neoformans/genética , Percepción de Quorum/genética , Factores de Transcripción/genética , Ciclo Celular/genética , Pared Celular/metabolismo , Criptococosis/microbiología , Proteínas Fúngicas/genética , Regulación Fúngica de la Expresión Génica/genética , Genómica , Meningitis Fúngica/genética , Péptidos/genética , Factores de Transcripción/metabolismo , Virulencia/genética , Factores de Virulencia/genética
19.
J Med Microbiol ; 69(11): 1308-1318, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32930658

RESUMEN

Introduction. Streptococcus pyogenes is a diverse virulent synthesis pathogen responsible for invasive systemic infections. Establishment of antibiotic resistance in the pathogen has produced a need for new antibiofilm agents to control the biofilm formation and reduce biofilm-associated resistance development.Aim. The present study investigates the in vitro antibiofilm activity of eucalyptol against S. pyogenes.Methodology. The antibiofilm potential of eucalyptol was assessed using a microdilution method and their biofilm inhibition efficacy was visualized by microscopic analysis. The biochemical assays were performed to assess the influence of eucalyptol on virulence productions. Real-time PCR analysis was performed to evaluate the expression profile of the virulence genes.Results. Eucalyptol showed significant antibiofilm potential in a dose-dependent manner without affecting bacterial growth. Eucalyptol at 300 µg ml-1 (biofilm inhibitory concentration) significantly inhibited the initial stage of biofilm formation in S. pyogenes. However, eucalyptol failed to diminish the mature biofilms of S. pyogenes at biofilm inhibitory concentration and it effectively reduced the biofilm formation on stainless steel, titanium, and silicone surfaces. The biochemical assay results revealed that eucalyptol greatly affects the cell-surface hydrophobicity, auto-aggregation, extracellular protease, haemolysis and hyaluronic acid synthesis. Further, the gene-expression analysis results showed significant downregulation of virulence gene expression upon eucalyptol treatment.Conclusion. The present study suggests that eucalyptol applies its antibiofilm assets by intruding the initial biofilm formation of S. pyogenes. Supplementary studies are needed to understand the mode of action involved in biofilm inhibition.


Asunto(s)
Antibacterianos/farmacología , Biopelículas/efectos de los fármacos , Eucaliptol/farmacología , Streptococcus pyogenes/efectos de los fármacos , Streptococcus pyogenes/genética , Factores de Virulencia/genética , Adhesión Bacteriana/efectos de los fármacos , Expresión Génica , Interacciones Hidrofóbicas e Hidrofílicas , Pruebas de Sensibilidad Microbiana , Streptococcus pyogenes/patogenicidad , Virulencia
20.
J Med Microbiol ; 69(11): 1285-1292, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32945764

RESUMEN

Introduction. Papiliotrema laurentii, formerly Cryptococcus laurentii, is typically isolated from environmental sources, but also occasionally from clinical specimens. Other close relatives may be misidentified as P. laurentii by phenotypic methods. P. laurentii usually lacks melanin; however, melanin-forming strains have also been isolated.Hypothesis/Gap Statement. Although melanin production by encapsulated budding yeasts is considered a major virulence factor, the comparative pathogenicity of melanin-forming and non-melanized environmental strains of P. laurentii has rarely been studied.Aim. We performed phenotypic and molecular identification and determined the genotypic heterogeneity among P. laurentii isolates. We also studied the pathogenicity of melanin-forming and non-melanized strains in normal and immunosuppressed mice.Methodology. Eleven environmental isolates were tested for their identity by Vitek2 and/or ID32C systems, and by PCR-sequencing of the internal transcribed spacer (ITS) region and D1/D2 domains of ribosomal DNA (rDNA). Genotypic heterogeneity was studied by sequence comparisons. The pathogenicity of melanized and non-melanized P. laurentii strains was studied in intravenously infected normal and immunosuppressed BALB/c mice.Results. Phenotypic methods identified seven of the environmental isolates, while PCR-sequencing of the ITS region and D1/D2 domains of rDNA detected two and five isolates, respectively, as P. laurentii. Sequence comparisons demonstrated genotypic heterogeneity among P. laurentii. The remaining four environmental isolates yielded expected results. None of the normal mice infected with 105 cells of melanized/non-melanized P. laurentii strains died. Infection of immunosuppressed mice with 107 cells caused higher mortality with non-melanized P. laurentii, while viable counts in brain/lung tissue were higher in mice infected with a melanized strain and were detectable for up to 14 days.Conclusion. Phenotypic methods lacked specificity, but PCR-sequencing of D1/D2 domains correctly identified P. laurentii and sequence comparisons demonstrated the genotypic heterogeneity of the isolates. Both melanized and non-melanized strains at a higher dose caused mortality in immunosuppressed mice and persisted in brain/lung tissue up to 14 days post-infection.


Asunto(s)
Basidiomycota/genética , Basidiomycota/patogenicidad , Microbiología Ambiental , Variación Genética , Micosis/microbiología , Animales , Basidiomycota/clasificación , ADN de Hongos/genética , ADN Intergénico/genética , Femenino , Genotipo , Huésped Inmunocomprometido , Melaninas , Ratones , Ratones Endogámicos BALB C , Técnicas de Tipificación Micológica , Filogenia , Análisis de Secuencia de ADN , Virulencia , Factores de Virulencia/genética
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA