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Brucella abortus is a facultatively extracellular-intracellular pathogen that encounters a diversity of environments within the host cell. We report that bacteria extracted from infected cells at late stages (48 h postinfection) of the intracellular life cycle significantly increase their ability to multiply in new target cells.
Pamela Altamirano-Silva; Marlen Cordero-Serrano; Joselyn Méndez-Montoya; Carlos Chacón-Díaz; Caterina Guzmán-Verri; Edgardo Moreno; Esteban Chaves-Olarte. Intracellular Passage Triggers a Molecular Response in Brucella abortus That Increases Its Infectiousness. Infection and Immunity 2021, 89, 1 .
AMA StylePamela Altamirano-Silva, Marlen Cordero-Serrano, Joselyn Méndez-Montoya, Carlos Chacón-Díaz, Caterina Guzmán-Verri, Edgardo Moreno, Esteban Chaves-Olarte. Intracellular Passage Triggers a Molecular Response in Brucella abortus That Increases Its Infectiousness. Infection and Immunity. 2021; 89 (7):1.
Chicago/Turabian StylePamela Altamirano-Silva; Marlen Cordero-Serrano; Joselyn Méndez-Montoya; Carlos Chacón-Díaz; Caterina Guzmán-Verri; Edgardo Moreno; Esteban Chaves-Olarte. 2021. "Intracellular Passage Triggers a Molecular Response in Brucella abortus That Increases Its Infectiousness." Infection and Immunity 89, no. 7: 1.
Brucella organisms are responsible for one of the most widespread bacterial zoonoses, named brucellosis. The disease affects several species of animals, including humans. One of the most intriguing aspects of the brucellae is that the various species show a ~97% similarity at the genome level. Still, the distinct Brucella species display different host preferences, zoonotic risk, and virulence. After 133 years of research, there are many aspects of the Brucella biology that remain poorly understood, such as host adaptation and virulence mechanisms. A strategy to understand these characteristics focuses on the relationship between the genomic diversity and host preference of the various Brucella species. Pseudogenization, genome reduction, single nucleotide polymorphism variation, number of tandem repeats, and mobile genetic elements are unveiled markers for host adaptation and virulence. Understanding the mechanisms of genome variability in the Brucella genus is relevant to comprehend the emergence of pathogens.
Marcela Suárez-Esquivel; Esteban Chaves-Olarte; Edgardo Moreno; Caterina Guzmán-Verri. Brucella Genomics: Macro and Micro Evolution. International Journal of Molecular Sciences 2020, 21, 7749 .
AMA StyleMarcela Suárez-Esquivel, Esteban Chaves-Olarte, Edgardo Moreno, Caterina Guzmán-Verri. Brucella Genomics: Macro and Micro Evolution. International Journal of Molecular Sciences. 2020; 21 (20):7749.
Chicago/Turabian StyleMarcela Suárez-Esquivel; Esteban Chaves-Olarte; Edgardo Moreno; Caterina Guzmán-Verri. 2020. "Brucella Genomics: Macro and Micro Evolution." International Journal of Molecular Sciences 21, no. 20: 7749.
C. difficile induces antibiotic-associated diarrhea due to the action of two secreted toxins, TcdA and TcdB. A considerable range of virulence among C. difficile strains has been widely reported. During a hospital outbreak, 46 isolates were collected that belonged to different genotypes. Of those, the majority corresponded to two virulent strains, the globally distributed Sequence Type 1 (ST1)_North American Pulsotype 1 (NAP1) and the endemic ST54_NAPCR1 genotypes, respectively. Whereas the virulence of the latter has been attributed to increased secretion of toxins and production of a highly cytotoxic TcdB, these characteristics do not explain the increased lethality of the former. We undertook a proteomic comparative approach of the isolates participating in the outbreak to look for proteins present in the exoproteome of the ST1_NAP1and ST54_NAPCR1 strains. We used a low virulent ST2_NAP4 strain isolated also in the outbreak as control. Dendrograms constructed using the exoproteomes of the strains were very similar to those created using genomic information, suggesting an association between secreted proteins and relative virulence of the strains. By 2D electrophoresis and mass spectrometry it was found that approximately half of the proteins are shared among strains of different genotypes. From the identified proteins, the surface-located SlpA draw our attention due to its detection in ST54_NAPCR1 exoproteomes. Biochemical analysis indicated that the processing of SlpA is different in the ST54_NAPCR1 strain and confirmed that this strain secretes more SlpA than its counterparts. Furthermore, SlpA from the ST54_NAPCR1 strain exerted an increased proinflammatory activity. Altogether, these results indicate that the exoproteome composition correlates with the C. difficile genotype and suggest that particular proteins secreted by some strains could synergize with the effects of TcdA and TcdB increasing their virulence.
Carlos Quesada-Gómez; Tatiana Murillo; Grettel Arce; Adriana Badilla-Lobo; Carolina Castro-Peña; José Molina; Diana López-Ureña; Sara González-Camacho; Bruno Lomonte; Carlos Chacón-Díaz; Cesar Rodríguez; Esteban Chaves-Olarte. Proteogenomic analysis of the Clostridium difficile exoproteome reveals a correlation between phylogenetic distribution and virulence potential. Anaerobe 2020, 62, 102151 .
AMA StyleCarlos Quesada-Gómez, Tatiana Murillo, Grettel Arce, Adriana Badilla-Lobo, Carolina Castro-Peña, José Molina, Diana López-Ureña, Sara González-Camacho, Bruno Lomonte, Carlos Chacón-Díaz, Cesar Rodríguez, Esteban Chaves-Olarte. Proteogenomic analysis of the Clostridium difficile exoproteome reveals a correlation between phylogenetic distribution and virulence potential. Anaerobe. 2020; 62 ():102151.
Chicago/Turabian StyleCarlos Quesada-Gómez; Tatiana Murillo; Grettel Arce; Adriana Badilla-Lobo; Carolina Castro-Peña; José Molina; Diana López-Ureña; Sara González-Camacho; Bruno Lomonte; Carlos Chacón-Díaz; Cesar Rodríguez; Esteban Chaves-Olarte. 2020. "Proteogenomic analysis of the Clostridium difficile exoproteome reveals a correlation between phylogenetic distribution and virulence potential." Anaerobe 62, no. : 102151.
Clostridium difficile induces antibiotic-associated diarrhea due to the release of toxin A (TcdA) and toxin B (TcdB), the latter being its main virulence factor. The epidemic strain NAP1/027 has an increased virulence attributed to different factors. We compared cellular intoxication by TcdBNAP1 with that by the reference strain VPI 10463 (TcdBVPI). In a mouse ligated intestinal loop model, TcdBNAP1 induced higher neutrophil recruitment, cytokine release, and epithelial damage than TcdBVPI. Both toxins modified the same panel of small GTPases and exhibited similar in vitro autoprocessing kinetics. On the basis of sequence variations in the frizzled-binding domain (FBD), we reasoned that TcdBVPI and TcdBNAP1 might have different receptor specificities. To test this possibility, we used a TcdB from a NAP1 variant strain (TcdBNAP1v) unable to glucosylate RhoA but with the same receptor-binding domains as TcdBNAP1. Cells were preincubated with TcdBNAP1v to block cellular receptors, prior to intoxication with either TcdBVPI or TcdBNAP1. Preincubation with TcdBNAP1v blocked RhoA glucosylation by TcdBNAP1 but not by TcdBVPI, indicating that the toxins use different host factors for cell entry. This crucial difference might explain the increased biological activity of TcdBNAP1 in the intestine, representing a contributing factor for the increased virulence of the NAP1/027 strain.
Diana López-Ureña; Josué Orozco-Aguilar; Yendry Chaves-Madrigal; Andrea Ramírez-Mata; Amanda Villalobos-Jimenez; Stefan Ost; Carlos Quesada-Gómez; César Rodríguez; Panagiotis Papatheodorou; Esteban Chaves-Olarte. Toxin B Variants from Clostridium difficile Strains VPI 10463 and NAP1/027 Share Similar Substrate Profile and Cellular Intoxication Kinetics but Use Different Host Cell Entry Factors. Toxins 2019, 11, 348 .
AMA StyleDiana López-Ureña, Josué Orozco-Aguilar, Yendry Chaves-Madrigal, Andrea Ramírez-Mata, Amanda Villalobos-Jimenez, Stefan Ost, Carlos Quesada-Gómez, César Rodríguez, Panagiotis Papatheodorou, Esteban Chaves-Olarte. Toxin B Variants from Clostridium difficile Strains VPI 10463 and NAP1/027 Share Similar Substrate Profile and Cellular Intoxication Kinetics but Use Different Host Cell Entry Factors. Toxins. 2019; 11 (6):348.
Chicago/Turabian StyleDiana López-Ureña; Josué Orozco-Aguilar; Yendry Chaves-Madrigal; Andrea Ramírez-Mata; Amanda Villalobos-Jimenez; Stefan Ost; Carlos Quesada-Gómez; César Rodríguez; Panagiotis Papatheodorou; Esteban Chaves-Olarte. 2019. "Toxin B Variants from Clostridium difficile Strains VPI 10463 and NAP1/027 Share Similar Substrate Profile and Cellular Intoxication Kinetics but Use Different Host Cell Entry Factors." Toxins 11, no. 6: 348.
Brucella abortus is a facultative extracellular-intracellular pathogen belonging to a group of Alphaproteobacteria that establishes close interactions with animal cells. This bacterium enters host cells in a membrane-bound compartment, avoiding the lysosomal route and reaching the endoplasmic reticulum through the action of the type IV secretion system, VirB. In this work, we demonstrate that the BvrR/BvrS two-component system senses the intracellular environment to mount the transcriptional response required for intracellular life adaptation. By combining a method to purify intracellularly extracted bacteria with a strategy that allows direct determination of BvrR phosphorylation, we showed that upon entrance to host cells, the regulatory protein BvrR was activated (BvrR-P) by phosphorylation at aspartate 58. This activation takes place in response to intracellular cues found in early compartments, such as low pH and nutrient deprivation. Furthermore, BvrR activation was followed by an increase in the expression of VjbR and VirB. The in vitro activation of this BvrR-P/VjbR/VirB virulence circuit rescued B. abortus from the inhibition of intracellular replication induced by bafilomycin treatment of cells, demonstrating the relevance of this mechanism for intracellular bacterial survival and replication. All together, our results indicate that B. abortus senses the transition from the extracellular to the intracellular milieu through BvrR/BvrS, allowing the bacterium to transit safely to its replicative niche. These results serve as a working model for understanding the role of this family of two-component systems in the adaptation to intracellular life of Alphaproteobacteria .
Pamela Altamirano-Silva; Jazmin Meza-Torres; Amanda Castillo-Zeledón; Nazareth Ruiz-Villalobos; Ana Mariel Zuñiga-Pereira; Carlos Chacón-Díaz; Edgardo Moreno; Caterina Guzmán-Verri; Esteban Chaves-Olarte. Brucella abortus Senses the Intracellular Environment through the BvrR/BvrS Two-Component System, Which Allows B. abortus To Adapt to Its Replicative Niche. Infection and Immunity 2018, 86, 1 .
AMA StylePamela Altamirano-Silva, Jazmin Meza-Torres, Amanda Castillo-Zeledón, Nazareth Ruiz-Villalobos, Ana Mariel Zuñiga-Pereira, Carlos Chacón-Díaz, Edgardo Moreno, Caterina Guzmán-Verri, Esteban Chaves-Olarte. Brucella abortus Senses the Intracellular Environment through the BvrR/BvrS Two-Component System, Which Allows B. abortus To Adapt to Its Replicative Niche. Infection and Immunity. 2018; 86 (4):1.
Chicago/Turabian StylePamela Altamirano-Silva; Jazmin Meza-Torres; Amanda Castillo-Zeledón; Nazareth Ruiz-Villalobos; Ana Mariel Zuñiga-Pereira; Carlos Chacón-Díaz; Edgardo Moreno; Caterina Guzmán-Verri; Esteban Chaves-Olarte. 2018. "Brucella abortus Senses the Intracellular Environment through the BvrR/BvrS Two-Component System, Which Allows B. abortus To Adapt to Its Replicative Niche." Infection and Immunity 86, no. 4: 1.
Clostridium difficile is a nosocomial agent affecting immunocompromised populations under antibiotic treatment. The clinical manifestations induced by this bacterium range from mild antibiotic-associated diarrhea to potentially fatal pseudomembranous colitis. Traditionally, all the signs and symptoms produced by C. difficile have been associated to the production of two toxins, toxin A and toxin B. Both toxins belong to the family of large clostridial cytotoxins (LCTs), and their mechanism of action relies on a series of complex steps. First, these toxins recognize cell-surface located receptors allowing the entrance in membrane-surrounded compartments. The toxins are then translocated through acid sensing-dependent conformational changes and the enzymatically active domain is released into the cytosol through an autoprocessing activity. This enzymatic domain modifies through glucosylation of small guanosine triphosphatase (GTPases) from the Rho and Ras families. Consequently, the signal transduction pathways mediated by these proteins are interrupted leading to the corresponding cytoskeletal alterations and different effects which might finally result in different types of cell death. In vivo, these toxins induce toxicity on epithelial cells lining the intestinal mucosa and induce a severe inflammatory reaction characterized by the recruitment of neutrophils and secretion of several cytokines. It is precisely a combination of dead intestinal epithelial cells combined with polymorphonuclear immune cells that constitutes the characteristic pseudomembrane observed in diarrheic depositions by patients suffering complications of this infection. In this chapter, the clinical manifestations induced by C. difficile toxins, the cellular consequences of their mechanism of action and the evolution of the pathogenicity locus where they are encoded are discussed in detail.
Diana López-Ureña; Carlos Quesada-Gómez; César Rodríguez; Esteban Chaves-Olarte. Role of Clostridium difficile Toxins in Antibiotic-Associated Diarrhea and Pseudomembranous Colitis. Toxins and Drug Discovery 2018, 153 -170.
AMA StyleDiana López-Ureña, Carlos Quesada-Gómez, César Rodríguez, Esteban Chaves-Olarte. Role of Clostridium difficile Toxins in Antibiotic-Associated Diarrhea and Pseudomembranous Colitis. Toxins and Drug Discovery. 2018; ():153-170.
Chicago/Turabian StyleDiana López-Ureña; Carlos Quesada-Gómez; César Rodríguez; Esteban Chaves-Olarte. 2018. "Role of Clostridium difficile Toxins in Antibiotic-Associated Diarrhea and Pseudomembranous Colitis." Toxins and Drug Discovery , no. : 153-170.
Brucellosis is a chronic bacterial disease caused by members of the genus Brucella. Among the classical species stands Brucella neotomae, until now, a pathogen limited to wood rats. However, we have identified two brucellosis human cases caused by B. neotomae, demonstrating that this species has zoonotic potential. Within almost 4 years of each other, a 64-year-old Costa Rican white Hispanic man and a 51-year-old Costa Rican white Hispanic man required medical care at public hospitals of Costa Rica. Their hematological and biochemical parameters were within normal limits. No adenopathies or visceral abnormalities were found. Both patients showed intermittent fever, disorientation, and general malaise and a positive Rose Bengal test compatible with Brucella infection. Blood and cerebrospinal fluid cultures rendered Gram-negative coccobacilli identified by genomic analysis as B. neotomae. After antibiotic treatment, the patients recovered with normal mental activities. This is the first report describing in detail the clinical disease caused by B. neotomae in two unrelated patients. In spite of previous claims, this bacterium keeps zoonotic potential. Proposals to generate vaccines by using B. neotomae as an immunogen must be reexamined and countries housing the natural reservoir must consider the zoonotic risk.
Juan M. Villalobos-Vindas; Ernesto Amuy; Elías Barquero-Calvo; Norman Rojas; Carlos Chacón-Díaz; Esteban Chaves-Olarte; Caterina Guzman-Verri; Edgardo Moreno. Brucellosis caused by the wood rat pathogen Brucella neotomae: two case reports. Journal of Medical Case Reports 2017, 11, 352 -352.
AMA StyleJuan M. Villalobos-Vindas, Ernesto Amuy, Elías Barquero-Calvo, Norman Rojas, Carlos Chacón-Díaz, Esteban Chaves-Olarte, Caterina Guzman-Verri, Edgardo Moreno. Brucellosis caused by the wood rat pathogen Brucella neotomae: two case reports. Journal of Medical Case Reports. 2017; 11 (1):352-352.
Chicago/Turabian StyleJuan M. Villalobos-Vindas; Ernesto Amuy; Elías Barquero-Calvo; Norman Rojas; Carlos Chacón-Díaz; Esteban Chaves-Olarte; Caterina Guzman-Verri; Edgardo Moreno. 2017. "Brucellosis caused by the wood rat pathogen Brucella neotomae: two case reports." Journal of Medical Case Reports 11, no. 1: 352-352.
Clostridium difficile is a nosocomial agent affecting immunocompromised population under antibiotic treatment. The clinical manifestations induced by this bacterium range from mild antibiotic-associated diarrhea to potentially fatal pseudomembranous colitis. Traditionally, all the signs and symptoms produced by C. difficile have been associated to the production of two toxins, toxin A and toxin B. Both toxins belong to the family of large clostridial cytotoxins (LCTs), and their mechanism of action relies on a series of complex steps. First, these toxins recognize cell-surface located receptors allowing the entrance in membrane-surrounded compartments. The toxins are then translocated through acid sensing-dependent conformational changes and the enzymatically active domain is released into the cytosol through an autoprocessing activity. This enzymatic domain modifies through glucosylation small guanosine triphosphatase (GTPases) from the Rho and Ras families. Consequently, the signal transduction pathways mediated by these proteins are interrupted leading to the corresponding cytoskeletal alterations and different effects which might finally result in different types of cell death. In vivo, these toxins induce toxicity on epithelial cells lining the intestinal mucosa and induce a severe inflammatory reaction characterized by the recruitment of neutrophils and secretion of several cytokines. It is precisely a combination of dead intestinal epithelial cells combined with polymorphonuclear immune cells what constitutes the characteristic pseudomembrane observed in diarrheic depositions by patients suffering complications of this infection. In this chapter, the clinical manifestations induced by C. difficile toxins, the cellular consequences of their mechanism of action and the evolution of the pathogenicity locus where they are encoded are discussed in detail.
Diana López-Ureña; Carlos Quesada-Gómez; César Rodríguez; Esteban Chaves-Olarte. Role of Clostridium difficile Toxins in Antibiotic-Associated Diarrhea and Pseudomembranous Colitis. Toxins and Drug Discovery 2016, 1 -18.
AMA StyleDiana López-Ureña, Carlos Quesada-Gómez, César Rodríguez, Esteban Chaves-Olarte. Role of Clostridium difficile Toxins in Antibiotic-Associated Diarrhea and Pseudomembranous Colitis. Toxins and Drug Discovery. 2016; ():1-18.
Chicago/Turabian StyleDiana López-Ureña; Carlos Quesada-Gómez; César Rodríguez; Esteban Chaves-Olarte. 2016. "Role of Clostridium difficile Toxins in Antibiotic-Associated Diarrhea and Pseudomembranous Colitis." Toxins and Drug Discovery , no. : 1-18.
Clostridium difficile strains within the hypervirulent clade 2 are responsible for nosocomial outbreaks worldwide. The increased pathogenic potential of these strains has been attributed to several factors but is still poorly understood. During a C. difficile outbreak, a strain from this clade was found to induce a variant cytopathic effect (CPE), different from the canonical arborizing CPE. This strain (NAP1 V ) belongs to the NAP1 genotype but to a ribotype different from the epidemic NAP1/RT027 strain. NAP1 V and NAP1 share some properties, including the overproduction of toxins, the binary toxin, and mutations in tcdC . NAP1 V is not resistant to fluoroquinolones, however. A comparative analysis of TcdB proteins from NAP1/RT027 and NAP1 V strains indicated that both target Rac, Cdc42, Rap, and R-Ras but only the former glucosylates RhoA. Thus, TcdB from hypervirulent clade 2 strains possesses an extended substrate profile, and RhoA is crucial for the type of CPE induced. Sequence comparison and structural modeling revealed that TcdB NAP1 and TcdB NAP1V share the receptor-binding and autoprocessing activities but vary in the glucosyltransferase domain, consistent with the different substrate profile. Whereas the two toxins displayed identical cytotoxic potencies, TcdB NAP1 induced a stronger proinflammatory response than TcdB NAP1V as determined in ex vivo experiments and animal models. Since immune activation at the level of intestinal mucosa is a hallmark of C. difficile -induced infections, we propose that the panel of substrates targeted by TcdB is a determining factor in the pathogenesis of this pathogen and in the differential virulence potential seen among C. difficile strains.
Carlos Quesada-Gómez; Diana López-Ureña; Nicole Chumbler; Heather K. Kroh; Carolina Castro-Peña; César Rodríguez; Josué Orozco-Aguilar; Sara González-Camacho; Alexandra Rucavado; Caterina Guzmán-Verri; Trevor D. Lawley; D. Borden Lacy; Esteban Chaves-Olarte. Analysis of TcdB Proteins within the Hypervirulent Clade 2 Reveals an Impact of RhoA Glucosylation on Clostridium difficile Proinflammatory Activities. Infection and Immunity 2016, 84, 856 -865.
AMA StyleCarlos Quesada-Gómez, Diana López-Ureña, Nicole Chumbler, Heather K. Kroh, Carolina Castro-Peña, César Rodríguez, Josué Orozco-Aguilar, Sara González-Camacho, Alexandra Rucavado, Caterina Guzmán-Verri, Trevor D. Lawley, D. Borden Lacy, Esteban Chaves-Olarte. Analysis of TcdB Proteins within the Hypervirulent Clade 2 Reveals an Impact of RhoA Glucosylation on Clostridium difficile Proinflammatory Activities. Infection and Immunity. 2016; 84 (3):856-865.
Chicago/Turabian StyleCarlos Quesada-Gómez; Diana López-Ureña; Nicole Chumbler; Heather K. Kroh; Carolina Castro-Peña; César Rodríguez; Josué Orozco-Aguilar; Sara González-Camacho; Alexandra Rucavado; Caterina Guzmán-Verri; Trevor D. Lawley; D. Borden Lacy; Esteban Chaves-Olarte. 2016. "Analysis of TcdB Proteins within the Hypervirulent Clade 2 Reveals an Impact of RhoA Glucosylation on Clostridium difficile Proinflammatory Activities." Infection and Immunity 84, no. 3: 856-865.
Canine brucellosis caused by Brucella canis is a disease of dogs and a zoonotic risk. B. canis harbors most of the virulence determinants defined for the genus, but its pathogenic strategy remains unclear since it has not been demonstrated that this natural rough bacterium is an intracellular pathogen. Studies of B. canis outbreaks in kennel facilities indicated that infected dogs displaying clinical signs did not present hematological alterations. A virulent B. canis strain isolated from those outbreaks readily replicated in different organs of mice for a protracted period. However, the levels of tumor necrosis factor alpha, interleukin-6 (IL-6), and IL-12 in serum were close to background levels. Furthermore, B. canis induced lower levels of gamma interferon, less inflammation of the spleen, and a reduced number of granulomas in the liver in mice than did B. abortus . When the interaction of B. canis with cells was studied ex vivo , two patterns were observed, a predominant scattered cell-associated pattern of nonviable bacteria and an infrequent intracellular replicative pattern of viable bacteria in a perinuclear location. The second pattern, responsible for the increase in intracellular multiplication, was dependent on the type IV secretion system VirB and was seen only if the inoculum used for cell infections was in early exponential phase. Intracellular replicative B. canis followed an intracellular trafficking route undistinguishable from that of B. abortus . Although B. canis induces a lower proinflammatory response and has a stealthier replication cycle, it still displays the pathogenic properties of the genus and the ability to persist in infected organs based on the ability to multiply intracellularly.
Carlos Chacón-Díaz; Pamela Altamirano-Silva; Gabriela González-Espinoza; María-Concepción Medina; Alejandro Alfaro-Alarcón; Laura Bouza-Mora; César Jiménez-Rojas; Melissa Wong; Elías Barquero-Calvo; Norman Rojas; Caterina Guzmán-Verri; Edgardo Moreno; Esteban Chaves-Olarte. Brucella canis Is an Intracellular Pathogen That Induces a Lower Proinflammatory Response than Smooth Zoonotic Counterparts. Infection and Immunity 2015, 83, 4861 -4870.
AMA StyleCarlos Chacón-Díaz, Pamela Altamirano-Silva, Gabriela González-Espinoza, María-Concepción Medina, Alejandro Alfaro-Alarcón, Laura Bouza-Mora, César Jiménez-Rojas, Melissa Wong, Elías Barquero-Calvo, Norman Rojas, Caterina Guzmán-Verri, Edgardo Moreno, Esteban Chaves-Olarte. Brucella canis Is an Intracellular Pathogen That Induces a Lower Proinflammatory Response than Smooth Zoonotic Counterparts. Infection and Immunity. 2015; 83 (12):4861-4870.
Chicago/Turabian StyleCarlos Chacón-Díaz; Pamela Altamirano-Silva; Gabriela González-Espinoza; María-Concepción Medina; Alejandro Alfaro-Alarcón; Laura Bouza-Mora; César Jiménez-Rojas; Melissa Wong; Elías Barquero-Calvo; Norman Rojas; Caterina Guzmán-Verri; Edgardo Moreno; Esteban Chaves-Olarte. 2015. "Brucella canis Is an Intracellular Pathogen That Induces a Lower Proinflammatory Response than Smooth Zoonotic Counterparts." Infection and Immunity 83, no. 12: 4861-4870.
The prevalence ofClostridium difficileinfections has increased due to the emergence of epidemic variants from diverse genetic lineages. Here we describe the emergence of a novel variant during an outbreak in a Costa Rican hospital that was associated with severe clinical presentations. ThisC. difficilevariant elicited higher white blood cell counts and caused disease in younger patients than did other strains isolated during the outbreak. Furthermore, it had a recurrence rate, a 30-day attributable disease rate, and disease severity as great as those of the epidemic strain NAP1. Pulsed-field gel electrophoresis genotyping indicated that the outbreak strains belong to a previously undescribed variant, designated NAPCR1. Whole-genome sequencing and ribotyping indicated that the NAPCR1variant belongs toC. difficileribotype 012 and sequence type 54, as does the reference strain 630. NAPCR1strains are resistant to fluoroquinolones due to a mutation ingyrA, and they possess an 18-bp deletion intcdCthat is characteristic of the epidemic, evolutionarily distinct,C. difficileNAP1 variant. NAPCR1genomes contain 10% more predicted genes than strain 630, most of which are of hypothetical function and are present on phages and other mobile genetic elements. The increased virulence of NAPCR1was confirmed by mortality rates in the hamster model and strong inflammatory responses induced by bacteria-free supernatants in the murine ligated loop model. However, NAPCR1strains do not synthesize toxin A and toxin B at levels comparable to those in NAP1 strains. Our results suggest that the pathogenic potential of this emergingC. difficilevariant is due to the acquisition of hypothetical functions associated with laterally acquired DNA.
Carlos Quesada-Gómez; Diana López-Ureña; Luis Acuña-Amador; Manuel Villalobos-Zúñiga; Tim Du; Rosemayre Freire; Caterina Guzman-Verri; María Del Mar Gamboa-Coronado; Trevor D. Lawley; Edgardo Moreno; Michael R. Mulvey; Gerly Brito; Evelyn Rodríguez-Cavallini; Cesar Rodriguez; Esteban Chaves-Olarte. Emergence of an Outbreak-Associated Clostridium difficile Variant with Increased Virulence. Journal of Clinical Microbiology 2015, 53, 1216 -1226.
AMA StyleCarlos Quesada-Gómez, Diana López-Ureña, Luis Acuña-Amador, Manuel Villalobos-Zúñiga, Tim Du, Rosemayre Freire, Caterina Guzman-Verri, María Del Mar Gamboa-Coronado, Trevor D. Lawley, Edgardo Moreno, Michael R. Mulvey, Gerly Brito, Evelyn Rodríguez-Cavallini, Cesar Rodriguez, Esteban Chaves-Olarte. Emergence of an Outbreak-Associated Clostridium difficile Variant with Increased Virulence. Journal of Clinical Microbiology. 2015; 53 (4):1216-1226.
Chicago/Turabian StyleCarlos Quesada-Gómez; Diana López-Ureña; Luis Acuña-Amador; Manuel Villalobos-Zúñiga; Tim Du; Rosemayre Freire; Caterina Guzman-Verri; María Del Mar Gamboa-Coronado; Trevor D. Lawley; Edgardo Moreno; Michael R. Mulvey; Gerly Brito; Evelyn Rodríguez-Cavallini; Cesar Rodriguez; Esteban Chaves-Olarte. 2015. "Emergence of an Outbreak-Associated Clostridium difficile Variant with Increased Virulence." Journal of Clinical Microbiology 53, no. 4: 1216-1226.
Brucella ceti infections have been increasingly reported in cetaceans. Brucellosis in these animals is associated with meningoencephalitis, abortion, discospondylitis’, subcutaneous abscesses, endometritis and other pathological conditions B. ceti infections have been frequently described in dolphins from both, the Atlantic and Pacific Oceans. In the Mediterranean Sea, only two reports have been made: one from the Italian Tyrrhenian Sea and the other from the Adriatic Sea. We describe the clinical and pathological features of three cases of B. ceti infections in three dolphins stranded in the Mediterranean Catalonian coast. One striped dolphin had neurobrucellosis, showing lethargy, incoordination and lateral swimming due to meningoencephalitis, A B. ceti infected bottlenose dolphin had discospondylitis, and another striped dolphin did not show clinical signs or lesions related to Brucella infection. A detailed characterization of the three B. ceti isolates was performed by bacteriological, molecular, protein and fatty acid analyses. All the B. ceti strains originating from Mediterranean dolphins cluster together in a distinct phylogenetic clade, close to that formed by B. ceti isolates from dolphins inhabiting the Atlantic Ocean. Our study confirms the severity of pathological signs in stranded dolphins and the relevance of B. ceti as a pathogen in the Mediterranean Sea.
Marcos Isidoro-Ayza; Nazareth Ruiz-Villalobos; Lola Pérez; Caterina Guzmán-Verri; Pilar M Muñoz; Fernando Alegre; Montserrat Barberán; Carlos Chacón-Díaz; Esteban Chaves-Olarte; Rocio González-Barrientos; Edgardo Moreno; José María Blasco; Mariano Domingo. Brucella cetiinfection in dolphins from the Western Mediterranean sea. BMC Veterinary Research 2014, 10, 1 -10.
AMA StyleMarcos Isidoro-Ayza, Nazareth Ruiz-Villalobos, Lola Pérez, Caterina Guzmán-Verri, Pilar M Muñoz, Fernando Alegre, Montserrat Barberán, Carlos Chacón-Díaz, Esteban Chaves-Olarte, Rocio González-Barrientos, Edgardo Moreno, José María Blasco, Mariano Domingo. Brucella cetiinfection in dolphins from the Western Mediterranean sea. BMC Veterinary Research. 2014; 10 (1):1-10.
Chicago/Turabian StyleMarcos Isidoro-Ayza; Nazareth Ruiz-Villalobos; Lola Pérez; Caterina Guzmán-Verri; Pilar M Muñoz; Fernando Alegre; Montserrat Barberán; Carlos Chacón-Díaz; Esteban Chaves-Olarte; Rocio González-Barrientos; Edgardo Moreno; José María Blasco; Mariano Domingo. 2014. "Brucella cetiinfection in dolphins from the Western Mediterranean sea." BMC Veterinary Research 10, no. 1: 1-10.
The pathogenesis of brucellosis depends on the ability of bacteria from the genus Brucella to invade and replicate within animal cells. To understand the molecular pathways used by Brucella spp. to reach its intracellular niche, robust and reproducible bacteria purification protocols that provide enough material for biochemical and molecular biology studies are essential. Here, we describe a detailed methodology designed to extract and purify viable brucellae from mammalian host cells at different time periods of their intracellular cycle. The yield of proteins and nucleic acids is sufficient to perform immunochemical analysis, genetic studies, transcriptomics, and proteomics among others.
Esteban Chaves-Olarte; Pamela Altamirano-Silva; Caterina Guzman-Verri; Edgardo Moreno. Purification of Intracellular Bacteria: Isolation of Viable Brucella abortus from Host Cells. Methods in Molecular Biology 2014, 1197, 245 -260.
AMA StyleEsteban Chaves-Olarte, Pamela Altamirano-Silva, Caterina Guzman-Verri, Edgardo Moreno. Purification of Intracellular Bacteria: Isolation of Viable Brucella abortus from Host Cells. Methods in Molecular Biology. 2014; 1197 ():245-260.
Chicago/Turabian StyleEsteban Chaves-Olarte; Pamela Altamirano-Silva; Caterina Guzman-Verri; Edgardo Moreno. 2014. "Purification of Intracellular Bacteria: Isolation of Viable Brucella abortus from Host Cells." Methods in Molecular Biology 1197, no. : 245-260.
Since the first case of brucellosis detected in a dolphin aborted fetus, an increasing number of Brucella ceti isolates has been reported in members of the two suborders of cetaceans: Mysticeti and Odontoceti. Serological surveys have shown that cetacean brucellosis may be distributed worldwide in the oceans. Although all B. ceti isolates have been included within the same species, three different groups have been recognized according to their preferred host, bacteriological properties, and distinct genetic traits: B. ceti dolphin type, B. ceti porpoise type, and B. ceti human type. It seems that B. ceti porpoise type is more closely related to B. ceti human isolates and B. pinnipedialis group, while B. ceti dolphin type seems ancestral to them. Based on comparative phylogenetic analysis, it is feasible that the B. ceti ancestor radiated in a terrestrial artiodactyl host close to the Raoellidae family about 58 million years ago. The more likely mode of transmission of B. ceti seems to be through sexual intercourse, maternal feeding, aborted fetuses, placental tissues, vertical transmission from mother to the fetus or through fish or helminth reservoirs. The B. ceti dolphin and porpoise types seem to display variable virulence in land animal models and low infectivity for humans. However, brucellosis in some dolphins and porpoises has been demonstrated to be a severe chronic disease, displaying significant clinical and pathological signs related to abortions, male infertility, neurobrucellosis, cardiopathies, bone and skin lesions, strandings, and death.
Caterina Guzman-Verri; Rocío González-Barrientos; Gabriela Hernández-Mora; Juan-Alberto Morales; Elias Barquero-Calvo; Esteban Chaves-Olarte; Edgardo Moreno. Brucella ceti and Brucellosis in Cetaceans. Frontiers in Cellular and Infection Microbiology 2012, 2, 3 .
AMA StyleCaterina Guzman-Verri, Rocío González-Barrientos, Gabriela Hernández-Mora, Juan-Alberto Morales, Elias Barquero-Calvo, Esteban Chaves-Olarte, Edgardo Moreno. Brucella ceti and Brucellosis in Cetaceans. Frontiers in Cellular and Infection Microbiology. 2012; 2 ():3.
Chicago/Turabian StyleCaterina Guzman-Verri; Rocío González-Barrientos; Gabriela Hernández-Mora; Juan-Alberto Morales; Elias Barquero-Calvo; Esteban Chaves-Olarte; Edgardo Moreno. 2012. "Brucella ceti and Brucellosis in Cetaceans." Frontiers in Cellular and Infection Microbiology 2, no. : 3.
The pathogenesis of Brucella is related to the ability to multiply intracellularly, an event controlled by the two-component system BvrR/BvrS (TCS BvrRS) and the type IV secretion machinery VirB (T4SS VirB). We have hypothesized that the TCS BvrRS transcriptionally regulates the T4SS VirB. To test this hypothesis, we have compared the levels of VirB proteins in the wild-type strain Brucella abortus 2308 and mutant strains devoid of the sensor and regulator genes ( bvrS and bvrR mutants, respectively). While the bvrR and bvrS mutants showed low levels of the VirB1, VirB5, VirB8, and VirB9 proteins, the same proteins were overexpressed in the bvrR mutant complemented with a plasmid carrying a functional bvrR gene. Quantitation of virB5 mRNA confirmed these data and indicated that the influence of the TCS BvrRS on the T4SS VirB occurs at the transcriptional level. The expression of the transcriptional activator VjbR also depended on the TCS BvrRS. In addition, we demonstrate a direct interaction between the promoter region of the VirB operon and the response regulator BvrR. Altogether these data demonstrate that the TCS BvrRS controls the expression of the T4SS VirB through direct and indirect mechanisms.
Carola Martínez-Núñez; Pamela Altamirano-Silva; Francisco Alvarado-Guillén; Edgardo Moreno; Caterina Guzmán-Verri; Esteban Chaves-Olarte. The Two-Component System BvrR/BvrS Regulates the Expression of the Type IV Secretion System VirB in Brucella abortus. Journal of Bacteriology 2010, 192, 5603 -5608.
AMA StyleCarola Martínez-Núñez, Pamela Altamirano-Silva, Francisco Alvarado-Guillén, Edgardo Moreno, Caterina Guzmán-Verri, Esteban Chaves-Olarte. The Two-Component System BvrR/BvrS Regulates the Expression of the Type IV Secretion System VirB in Brucella abortus. Journal of Bacteriology. 2010; 192 (21):5603-5608.
Chicago/Turabian StyleCarola Martínez-Núñez; Pamela Altamirano-Silva; Francisco Alvarado-Guillén; Edgardo Moreno; Caterina Guzmán-Verri; Esteban Chaves-Olarte. 2010. "The Two-Component System BvrR/BvrS Regulates the Expression of the Type IV Secretion System VirB in Brucella abortus." Journal of Bacteriology 192, no. 21: 5603-5608.