Laboratorio Of Microbiologia Clinica

Mexico City, Mexico

Laboratorio Of Microbiologia Clinica

Mexico City, Mexico
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Santos R.C.V.,Laboratorio Of Microbiologia Clinica | Santos R.C.V.,Grande Rio University | Santos R.C.V.,University of Barcelona | Rico M.A.P.,University of Barcelona | And 5 more authors.
Inflammation | Year: 2011

Zymosan is a yeast cell wall particle that activates several cell lines, especially macrophages, resulting in the stimulated secretion of inflammatory products including tumor necrosis factor alpha (TNF-α) and arachidonic acid. Cyclooxygenase-2 (COX-2) is an immediate early gene induced by several stimuli in macrophages. The following research aimed to investigate the regions of COX-2 promoter gene that mediate the inductive effects of zymosan. Transient transfections with a series of COX-2 promoter-mutation constructs were performed to further elucidate the effects of zymosan on COX-2 transcription. Exposure to zymosan (50 μg/mL for 24 h) markedly enhanced the relative luciferase activity in RAW 264.7 macrophages (mouse leukemic monocyte macrophage cell line) transfected with COX-2 luciferase promoter constructs. Deletion on the CCAAT-enhancer binding protein (C/EBP) and nuclear factor kappa B (NF-kappa B) binding site resulted in an important decrease in reporter gene activity and a deletion of NF-kappa B and C/EBP with mutation of the cyclic adenosine monophosphate response element (CRE) and/or activator protein-1 totally abolished the reporter gene activity induced by zymosan. These findings provide further insight into the signal transduction pathways involved in COX-2 gene activated by zymosan in macrophages. © 2010 Springer Science+Business Media, LLC.


Ambrosi C.,University of Rome La Sapienza | Pompili M.,University of Rome La Sapienza | Scribano D.,University of Chieti Pescara | Limongi D.,University Telematica San Raffaele Rome | And 6 more authors.
International journal of medical microbiology : IJMM | Year: 2015

Through the action of the type three secretion system (T3SS) Shigella flexneri delivers several effectors into host cells to promote cellular invasion, multiplication and to exploit host-cell signaling pathways to modulate the host innate immune response. Although much progress has been made in the understanding of many type III effectors, the molecular and cellular mechanism of the OspB effector is still poorly characterized. In this study we present new evidence that better elucidates the role of OspB as pro-inflammatory factor at very early stages of infection. Indeed, we demonstrate that, during the first hour of infection, OspB is required for full activation of ERK1/2 and p38 MAPKs and the cytosolic phospholipase A(2) (cPLA(2)). Activation of cPLA(2) ultimately leads to the production and secretion of PMN chemoattractant metabolite(s) uncoupled with release of IL-8. Moreover, we also present evidence that OspB is required for the development of the full and promptly inflammatory reaction characteristic of S. flexneri wild-type infection in vivo. Based on OspB and OspF similarity (both effectors share similar transcription regulation, temporal secretion into host cells and nuclear localization) we hypothesized that OspB and OspF effectors may form a pair aimed at modulating the host cell response throughout the infection process, with opposite effects. A model is presented to illustrate how OspB activity would promote S. flexneri invasion and bacterial dissemination at early critical phases of infection. Copyright © 2014 Elsevier GmbH. All rights reserved.


Ambrosi C.,University of Rome La Sapienza | Pompili M.,University of Rome La Sapienza | Scribano D.,University of Chieti Pescara | Limongi D.,University Telematica San Raffaele | And 6 more authors.
International Journal of Medical Microbiology | Year: 2015

Through the action of the type three secretion system (T3SS) Shigella flexneri delivers several effectors into host cells to promote cellular invasion, multiplication and to exploit host-cell signaling pathways to modulate the host innate immune response. Although much progress has been made in the understanding of many type III effectors, the molecular and cellular mechanism of the OspB effector is still poorly characterized. In this study we present new evidence that better elucidates the role of OspB as pro-inflammatory factor at very early stages of infection. Indeed, we demonstrate that, during the first hour of infection, OspB is required for full activation of ERK1/2 and p38 MAPKs and the cytosolic phospholipase A2 (cPLA2). Activation of cPLA2 ultimately leads to the production and secretion of PMN chemoattractant metabolite(s) uncoupled with release of IL-8. Moreover, we also present evidence that OspB is required for the development of the full and promptly inflammatory reaction characteristic of S. flexneri wild-type infection in vivo. Based on OspB and OspF similarity (both effectors share similar transcription regulation, temporal secretion into host cells and nuclear localization) we hypothesized that OspB and OspF effectors may form a pair aimed at modulating the host cell response throughout the infection process, with opposite effects. A model is presented to illustrate how OspB activity would promote S. flexneri invasion and bacterial dissemination at early critical phases of infection. © 2014 Elsevier GmbH.


Recipients of SOT and HSCT constitute a risk group for becoming ill with tuberculosis (TB). The prevalence of active TB in patients undergoing TOS is higher than in patients undergoing HSCT, probably for the shortest period of immunosuppression of the latter. Most TB cases occur in transplant patients by reactivation of latent infection after immunosuppression, which occurs most often within the first year post-transplant, causing graft loss and in some cases death. Relevant variables to assess the risk of TB infection in a transplant recipient are the medical history of donor and recipient, images, microbiology and tuberculin tests and interferon gamma levels. PPD is routinely performed in the donor and in the recipient before transplantation. If PPD is > 5 mm in the recipient or > 10 mm in the donor, it is neccesary to exclude active TB (pulmonary and renal) (A2). It is recommended chemoprophylaxis in recipients PPD (+) and in recipients with recent seroconversion (B3), if the donor has a history of untreated TB, there was contact to someone with active TB (B3), the radiological imeges are suspect (A2) and interferon gamma release assays is (+) (B2). The selected drug is isoniazid (C3).


Ares M.A.,Laboratorio Of Microbiologia Clinica | Ares M.A.,Hospital Of Pediatria | Alcantar-Curiel M.D.,National Autonomous University of Mexico | Jimenez-Galicia C.,Laboratorio Of Microbiologia Clinica | And 3 more authors.
Chemotherapy | Year: 2014

Background: Gram-negative bacilli are the most common bacteria causing nosocomial bloodstream infections (NBSIs) in Latin American countries. Methods: The antibiotic resistance profiles of Gram-negative bacilli isolated from blood cultures in pediatric patients with NBSIs over a 3-year period in a tertiary care pediatric hospital in Mexico City were determined using the VITEK-2 system. Sixteen antibiotics were tested to ascertain the resistance rate and the minimum inhibitory concentration using the Clinical Laboratory Standards Institute (CLSI) broth micro-dilution method as a reference. Results: A total of 931 isolates were recovered from 847 clinically significant episodes of NBSI. Of these, 477 (51.2%) were caused by Gram-negative bacilli. The most common Gram-negative bacilli found were Klebsiella pneumoniae (30.4%), Escherichia coli (18.9%), Enterobacter cloacae (15.1%), Pseudomonas aeruginosa (9.9%), and Acinetobacter baumannii (4.6%). More than 45 and 60% of the K. pneumoniae and E. coli isolates, respectively, were resistant to cephalosporins, and 64% of the E. coli isolates were resistant to fluoroquinolones. A. baumannii exhibited low rates of resistance to antibiotics tested. In the E. cloacae and P. aeruginosa isolates, no rates of resistance higher than 38% were observed. Conclusions: In this study, we found that the proportion of NBSIs due to antibiotic-resistant organisms is increasing in a tertiary care pediatric hospital of Mexico. © 2014 S. Karger AG, Basel.

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