Sergio Vaca

Universidad Nacional Autónoma de México

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Erasmo Negrete‐Abascal

Autonomous University of Tlaxcala

Gloria Luz Paniagua‐Contreras

Universidad Nacional Autónoma de México

Eric Monroy‐Pérez

Universidad Nacional Autónoma de México

Felipe Vaca‐Paniagua

Universidad Nacional Autónoma de México

Candelario Vázquez-Crúz

Benemérita Universidad Autónoma de Puebla

Alina Uribe-García

Autonomous University of Tlaxcala

Eric Monroy

Autonomous University of Tlaxcala

José Raymundo Rodríguez‐Moctezuma

Mexican Social Security Institute

Gloria Luz Paniagua

Universidad Nacional Autónoma de México

Víctor M. Pérez-Márquez

Secretariat of Agriculture, Livestock, Rural Development, Fisheries and Food

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Universidad Nacional Autónoma de México

Autonomous University of Tlaxcala

Mexican Social Security Institute

Instituto Politécnico Nacional

Center for Research and Advanced Studies of the National Polytechnic Institute

Universidad Autónoma Metropolitana

Benemérita Universidad Autónoma de Puebla

Secretariat of Agriculture, Livestock, Rural Development, Fisheries and Food

Centro de Investigación en Materiales Avanzados

Instituto de Investigaciones en Ciencias de la Salud

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Filosofía Lean y Gerencia de Operaciones: El caso de las empresas de Ambato, Ecuador

Congreso de Ciencia y Tecnología ESPE (2018)

Yanet Marisol Ortega Freire Sergio Vaca

El propósito de este estudio es brindar, desde la perspectiva de la filosofía Lean, una visión panorámica del manejo de los procesos en las empresas del Cantón Ambato, Ecuador, a través de la cual se determinan los aspectos claves de este sistema de trabajo con énfasis en los procedimientos para la eliminación de desperdicios que no aportan valor. La metodología se basa en un estudio macro del sector industrial y comercial, llevado a cabo en el 2016. La recopilación de información se realiza mediante un estudio de campo con entrevistas estructuradas, dirigidas a los administradores de las empresas. Los resultados obtenidos reflejan la cultura en el campo de la optimización de recursos, así como también demuestran el nivel de conocimientos del modelo especialmente en términos de desperdicios, sobreproducción, distribución del espacio y mejora continua. En las conclusiones se deduce que las entidades de la zona tienen implementados mecanismos de mejora continua en los procesos, aunque ciertas prácticas para cumplir con los propósitos Lean requieren ser perfeccionadas.

10.24133/cctespe.v13i1.819

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Secreted Proteins of Avibacterium paragallinarum Are Lethal for Chicken Embryo

Annals of the New York Academy of Sciences (2008)

Víctor M. Pérez-Márquez A. Pérez-Méndez Jorge Ibarra‐Caballero Gabriela Gómez‐Lugo Candelario Vázquez-Crúz

Avibacterium paragallinarum causes infectious coryza in chickens. This bacterium secretes proteins of 110 kDa (a putative RTX protein) and 120 kDa. Expression of these proteins increases by the addition of CaCl 2 , MgSO 4 , MnSO 4 , or ferric ammonium citrate and diminishes with CuSO 4 or ZnCl 2 . Protein expression is optimal at 37°C and pH 7.5. Mortality (90–100%) of chicken embryos was observed when secreted proteins (SPs) from A. paragallinarum reference or field isolates (serogroup A or C) were inoculated via yolk sac and was not observed when SPs from A. avium , a chicken respiratory tract indigenous bacterium, were inoculated. A. paragallinarum SPs could contain toxins responsible for the embryo deaths. Indeed, presence of the putative RTX protein of 110 kDa was confirmed by Western blotting with antibodies against the Actinobacillus pleuropneumoniae RTX ApxI, a closely related RTX protein.

Actinobacillus pleuropneumoniae

Yolk

10.1196/annals.1428.007

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Pyocin types of clinical strains of Pseudomonas aeruginosa isolated in Morelia, México (1980-1984).

PubMed (1986)

Cervantes Vega C Jaime E. Villena Padilla Me Rivera An Sergio Vaca

29 types sont isoles. Les types 1, 3, 5 et 10 representant 70% des souches. Les resultats suggerent qu'un taux eleve d'infections croisees dues a P.a. est rencontre dans les institutions etudiees

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Gallibacterium elongation factor-Tu possesses amyloid-like protein characteristics, participates in cell adhesion, and is present in biofilms

The Journal of Microbiology (2017)

Ana Jaqueline López-Ochoa Juan Fernando Montes-García Candelario Vázquez-Crúz Patricia Sánchez Alonso Víctor M. Pérez-Márquez

Amyloid (mycology)

Polyclonal antibodies

Congo red

10.1007/s12275-017-7077-0

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Citations (30)

Outer membrane vesicles of Pasteurella multocida contain virulence factors

MicrobiologyOpen (2014)

Miguel A. Fernández‐Rojas Sergio Vaca Magda Reyes‐López Mireya de la Garza Francisco Aguilar‐Romero

Abstract Pasteurella multocida (Pm) is a gram‐negative bacterium able to infect different animal species, including human beings. This bacterium causes economic losses to the livestock industry because of its high morbidity and mortality in animals. In this work, we report the characterization of outer membrane vesicles (OMVs) released into the culture medium by different Pm serogroups. Purified OMVs in the range of 50–300 nm were observed by electron microscopy. Serum obtained from chickens infected with Pm recognized several proteins from Pm OMVs. Additionally, rabbit antiserum directed against a secreted protease from Actinobacillus pleuropneumoniae recognized a similar protein in the Pm OVMs, suggesting that OMVs from these bacterial species contain common immunogenic proteins. OmpA, a multifunctional protein, was identified in OMVs from different Pm serogroups, and its concentration was twofold higher in OMVs from Pm serogroups B and D than in OMVs from other serogroups. Three outer membrane proteins were also identified: OmpH, OmpW, and transferrin‐binding protein. Three bands of 65, 110, and 250 kDa with proteolytic activity were detected in Pm OMVs of serogroups A and E. Additionally, β ‐lactamase activity was detected only in OMVs from Pm 12945 Amp r (serogroup A). Pm OMVs may be involved in different aspects of disease pathogenesis.

Virulence factor

10.1002/mbo3.201

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Antibiotic and heavy metal resistance of Aeromonas hydrophila isolated from charal (Chirostoma humboldtianum,Valenciannes, 1835)

Hidrobiológica (2006)

Gloria Luz Paniagua Eric Monroy Magdalena Perches Erasmo Negrete Octavio Garcı́a

Antibiotic and heavy metal susceptibilities of twenty Aeromonas hydrophila strains, isolated from the gastrointestinal tract of the charal (Chirostoma humboldtianum), an autochthonous Mexican fish, were analyzed. All strains produced β-lactamase and were resistant to penicillin and dicloxacillin, showing single peak for minimum inhibitory concentration (MIC) distributions at 2000-4000 µg/mL and 500-1000 µg/ml, respectively. Ampicillin MIC distribution was bimodal with 20% resistant strains (125-250 µg/ml) and 80% highly resistant ones (500-4000 µg/ml). All strains were susceptible to ceftriaxone (MIC= 3.9 µg/ml) and all but one were susceptible to cefuroxime (3.9 µg/ml and 62.5 µg/ml). All strains had a single MIC distribution pattern for lead (800-3200 µg/ml), and mercury (20 µg/ml) and were considered resistant and susceptible to these ions, respectively. Fifteen percent of the isolates were resistant to arsenite (MIC= 400-800 µg/ml) and all were susceptible to silver (MIC= 1.25-2.5µg/ml), chromate (MIC= 93.5-375 µg/ml), and zinc (MIC=21.25-42.5 µg/ml).

Minimum bactericidal concentration

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Expression of enterotoxin-coding genes in methicillin-resistant Staphylococcus aureusstrains isolated from Mexican haemodialysis patients

Annals of Clinical Microbiology and Antimicrobials (2014)

Gloria Luz Paniagua‐Contreras Eric Monroy‐Pérez Felipe Vaca‐Paniagua José Raymundo Rodríguez‐Moctezuma Sergio Vaca

Methicillin-resistant Staphylococcus aureus (MRSA) causes severe catheter-related infections in haemodialysis patients ranging from local-site infections and septic thrombophlebitis to bacteraemia but the associated virulence factors and exotoxins remain unclear. We employed an in vitro infection model using reconstituted human epithelium (RHE) to analyse the expression profiles of 4 virulence genes and 12 exotoxin-coding virulence genes in 21 MRSA strains isolated from catheter-related infections in 21 Mexican patients undergoing haemodialysis. All 21 strains (100%) expressed the seg, seh, sei, eta, etb, or hla genes coding staphylococcal toxins. Eleven MRSA strains (52.3%) expressed the sea gene coding staphylococcal enterotoxin A, and two strains (9.5%) expressed the v8 gene coding serine protease. The tst, chp, and arcA genes coding toxic shock syndrome toxin 1, chemotaxis inhibitory protein, and arginine deiminase, respectively, were expressed in separate single strains (4.7%). The most frequent expression profile (42.8% of the strains) comprised seg, seh, sei, eta, etb, and hla. It is likely that the SEG, SEH, SEI, ETA, ETB, and Hla toxins may play a role in MRSA catheter-related infections. Consideration of these toxins in the development of a vaccine or as targets for monoclonal antibody therapy could provide an improved therapeutic strategy for the treatment of catheter-related infections in haemodialysis patients.

10.1186/s12941-014-0055-z

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Citations (2)

[Restoration of transcription antitermination of N- bacteriophages in Escherichia coli with a mutant RNA polymerase].

PubMed (1994)

Bulmaro Cisneros Sergio Vaca Luis Sosa Cecilia Montáñez

The N protein of bacteriophage lambda modifies Escherichia coli RNA polymerase in such a way that it transcribes through termination signals, in a process called antitermination. In general N-mutants are not able to perform transcription antitermination. In this paper we report the suppression of N7 and Nmar3 mutations by Escherichia coli ron-lon strain. The lon mutation causes the N protein half-life to raise, suggesting that excess of N7 fragment or Nmar3 protein overcome the defect in antitermination. Under these conditions the lambda N-phages produced a titer similar to lambda wild type, although the plaques were smaller. These observations highlight the relevance of N half life in the regulation of transcription antitermination.

Antitermination

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Lambda phage

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Frequency and expression of ALS and HWP1 genotypes in Candida albicans strains isolated from Mexican patients suffering from vaginal candidosis

Mycoses (2012)

Eric Monroy‐Pérez Teresita Sáinz‐Espuñes Gloria Luz Paniagua‐Contreras Erasmo Negrete‐Abascal José Raymundo Rodríguez‐Moctezuma

To detect the frequency and expression of eight ALS (agglutinin-like sequence) genes and the HWP1 genotype in a group of Candida albicans strains isolated from Mexican women suffering from vaginal candidosis. A group of 264 women (age 15-57 years) with vaginal infections were evaluated. C. albicans was identified by PCR amplification of the rRNA internal transcribed spacer regions ITS1 and ITS2. The ALS and HWP1 genes were identified by conventional PCR, and their expression levels were determined by real-time PCR after growing C. albicans strains in reconstituted human vaginal epithelium (RHVE). C. albicans was identified in 50 women (18.9%). The genotypic frequencies were ALS1 100%, ALS2 60%, ALS3 36%, ALS4 54%, ALS5 70%, ALS6 56%, ALS7 64%, ALS9 66% and HWP1 92%. The most frequently expressed genes in the strains harbouring all of the genes were ALS4 (100%), ALS1 (87.5%), ALS2 (87.5%), ALS3 (87.5%), ALS5 (87.5%), ALS7 (87.5%) and HWP1 (75.0%). Nineteen per cent of the vaginal infections were caused by C. albicans, and a high proportion of the strains carried genes encoding proteins involved in adhesion to epithelia. The ALS and HWP1 genes were expressed in RHVE, suggesting that the Als and Hwp1 proteins play an important role in the pathogenesis of the infection.

10.1111/j.1439-0507.2012.02188.x

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Virulence Markers in <i>Staphylococcus aureus</i> Strains Isolated from Hemodialysis Catheters of Mexican Patients

Advances in Microbiology (2012)

Gloria Luz Paniagua‐Contreras Teresita Sáinz‐Espuñes Eric Monroy‐Pérez José Raymundo Rodríguez‐Moctezuma Diego Arenas‐Aranda

Methicillin-resistant Staphylococcus aureus is an increasingly important cause of nosocomial bacterial infections worldwide. S. aureus is responsible for several pathologies, including skin infections, endocarditis, meningitis, deep-tissue ulcers, and sepsis. S. aureus biofilm formation on catheters and other medical devices is a major post-operative concern, because biofilms are often the source of persistent and difficult to treat bacterial infections. While catheter-related S. aureus infections have been reported, the strains responsible for these infections have not been genetically characterized. We genetically characterized S. aureus strains isolated from hemodialysis catheters in Mexican patients. The frequency of 35 genes coding for adhesins, toxins, and other virulence-associated products in the 55 isolated S. aureus strains was determined using PCR, while real-time PCR was used to examine the level of gene expression. Of the 55 S. aureus strains isolated from 109 patients, 45 (81.8%) were determined to be methicillin-resistant. The icaA, rbf, sarA, and agr genes are involved in biofilm formation and bacterial dispersion and were detected in 96.3%, 40.0%, 74.5%, and 100% of S. aureus strains, respectively, and 70.9% of the strains formed a detectable biofilm. Interestingly, 67.2% of the strains contained the icaA, agr, spa, clfA, sdrC, sdrD, sdrE, seg, seh, and sei genes, suggesting that this gene combination is important for successful catheter colonization. The results of this study provide significant insight into the virulence gene make-up of catheter-colonizing S. aureus strains, and will assist in developing a more targeted treatment approach for persistent S. aureus biofilm contamination of medical devices.

10.4236/aim.2012.24061

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Citations (28)