Cultivable Microbiome Approach Applied to Cervical Cancer Exploration.

Traditional microbiological methodology is valuable and essential for microbiota composition description and microbe role assignations at different anatomical sites, including cervical and vaginal tissues; that, combined with molecular biology strategies and modern identification approaches, could give a better perspective of the microbiome under different circumstances. This pilot work aimed to describe the differences in microbiota composition in non-cancer women and women with cervical cancer through a culturomics approach combining culture techniques with Vitek mass spectrometry and 16S rDNA sequencing. To determine the possible differences, diverse statistical, diversity, and multivariate analyses were applied; the results indicated a different microbiota composition between non-cancer women and cervical cancer patients. The Firmicutes phylum dominated the non-cancer (NC) group, whereas the cervical cancer (CC) group was characterized by the predominance of Firmicutes and Proteobacteria phyla; there was a depletion of lactic acid bacteria, an increase in the diversity of anaerobes, and opportunistic and non-typical human microbiota isolates were present. In this context, we hypothesize and propose a model in which microbial composition and dynamics may be essential for maintaining the balance in the cervical microenvironment or can be pro-oncogenesis microenvironmental mediators in a process called Ying-Yang or have a protagonist/antagonist microbiota role.

Clostridioides Difficile in Latin America: An Epidemiological Overview.

Clostridioides difficile infection is one of the most significant causes of nosocomial diarrhea associated with antibiotic use worldwide. In recent years, the incidence of Clostridioides difficile infection in Latin American countries has increased due to the emergence and spread of epidemic Clostridioides difficile strains, such as RT027/NAP1/ST1, RT078/ST11, and RT017/ST37; additionally, endemic multi-drug-resistant strains have recently appeared due to the lack of heterogeneous diagnostic algorithms and guidelines for antibiotic use in each country. The aim of this review is to present the latest information regarding Clostridioides difficile and emphasize the importance of epidemiological surveillance of this pathogen in Latin American countries.

Design of a Multi-Epitope Vaccine against Tuberculosis from Mycobacterium tuberculosis PE_PGRS49 and PE_PGRS56 Proteins by Reverse Vaccinology.

Tuberculosis is a disease caused by Mycobacterium tuberculosis, representing the second leading cause of death by an infectious agent worldwide. The available vaccine against this disease has insufficient coverage and variable efficacy, accounting for a high number of cases worldwide. In fact, an estimated third of the world's population has a latent infection. Therefore, developing new vaccines is crucial to preventing it. In this study, the highly antigenic PE_PGRS49 and PE_PGRS56 proteins were analyzed. These proteins were used for predicting T- and B-cell epitopes and for human leukocyte antigen (HLA) protein binding efficiency. Epitopes GGAGGNGSLSS, FAGAGGQGGLGG, GIGGGTQSATGLG (PE_PGRS49), and GTGWNGGKGDTG (PE_PGRS56) were selected based on their best physicochemical, antigenic, non-allergenic, and non-toxic properties and coupled to HLA I and HLA II structures for in silico assays. A construct with an adjuvant (RS09) plus each epitope joined by GPGPG linkers was designed, and the stability of the HLA-coupled construct was further evaluated by molecular dynamics simulations. Although experimental and in vivo studies are still necessary to ensure its protective effect against the disease, this study shows that the vaccine construct is dynamically stable and potentially effective against tuberculosis.

Molecular typification of Escherichia coli from community-acquired urinary tract infections in Mexico.

One hundred and five uropathogenic Escherichia coli (UPEC) strains from patients with community-acquired urinary tract infections were characterized according to phylogenetic group, virulence factors, serogroup, antibiotic resistance, and genotype. The pathogenic phylogenetic groups (B2, D, and F) were found in 71.4% of the tested strains. Among them, the main uropathogenic serogroups were O8, O25, and O75, in which 97.1% of the strains had a multidrug-resistant profile. Sixteen virulence genes were analysed using a combination of polymerase chain reaction (PCR) assays, with the fimH, irp-2, iutA, aer, iucC, PAI, sat, iroN, usp, and cnf1 genes being mainly found in pathogenic phylogroups. The E. coli O25b-ST131 clone was identified in 32% of the strains assigned to the pathogenic phylogroup B2. These findings demonstrate that virulence genes encoding adhesin components, iron-acquisition systems, toxins, and pathogenicity-associated islands were highly prevalent among the pathogenic phylogroup of UPEC strains.

Identification and characterization of class 1 integrons among multidrug-resistant uropathogenic Escherichia coli strains in Mexico.

This study aimed to identify and characterize integrons among multidrug-resistant (MDR) uropathogenic Escherichia coli (UPEC) from outpatients in Mexico City, Mexico. PCR assays were used to screen for the presence of class 1, 2 and 3 integrons, whose PCR products were sequenced to identify the inserted gene cassettes within the variable regions. Out of 83 tested strains, 53 (63.9%) were positive for the presence of class 1 integrons, whereas no integrons were detected in the remaining strains, regardless of their classes. Most of the strains carrying the intI1 gene belonged to the extraintestinal B2 (41.5%) and commensal A (32.1%) phylogroups, and to a lesser extent, the extraintestinal D (20.8%) and commensal B1 (5.7%) phylogroups. Moreover, 8 different gene cassette arrangements were detected, with dfrA17 and aadA5 being the most common (32.1% of the class 1 integron-positive strains), which confer resistance to trimethoprim/sulfamethoxazole and aminoglycosides, respectively. Our results suggest that class 1 integrons are widely distributed among MDR-UPEC strains in Mexico, which may directly or indirectly contribute to the selection of MDR strains. These findings are important for a better understanding of the factors and mechanisms that promote multidrug resistance among UPEC strains.

Characterization and use in neutralization assays of avian influenza codon-optimized H5 and H7 retroviral pseudotypes.

Influenza is a relevant problem for public and animal health, with a significant economic impact. In recent years, outbreaks of avian influenza virus have resulted in devastating losses in the poultry industry worldwide, and although its transmission to humans is very rare, there is always a potential risk for an even more severe outbreak. Currently, vaccination is considered the most effective tool for the control and prevention of influenza infections in both humans and animals. The maintenance of animal welfare and the successful implementation of animal health programs depend on the timely administration of vaccines, which must comply with quality specifications indicated by health authorities; for example, the capability to ensure a minimum antibody titer. The production of viral antigens used in these tests can pose a biosafety risk, and some viral strains can be difficult to grow. Therefore, new biotechnological alternatives are required to overcome these disadvantages. In this study, we produced pseudotypes carrying H5 and H7 hemagglutinins from lowly and highly pathogenic avian influenza viruses. These pseudotypes were used in neutralization assays to detect neutralizing antibodies in avian sera, which were confirmed positive by inhibition of the hemagglutination test. Our results showed that the pseudotype neutralization assay is a viable alternative for the detection of neutralizing antibodies, by demonstrating subtype specificity and requiring reduced biosafety requirements. Therefore, it represents a versatile platform that can facilitate technology transfer protocols between laboratories, and an immediate application in serological tools for quality control of veterinary vaccines against avian influenza.

Flagella, Type I Fimbriae and Curli of Uropathogenic Escherichia coli Promote the Release of Proinflammatory Cytokines in a Coculture System.

BACKGROUND: Urinary tract infections (UTIs) are a public health problem in Mexico, and uropathogenic Escherichia coli (UPEC) is one of the main etiological agents. Flagella, type I fimbriae, and curli promote the ability of these bacteria to successfully colonize its host. AIM: This study aimed to determine whether flagella-, type I fimbriae-, and curli-expressing UPEC induces the release of proinflammatory cytokines in an established coculture system. METHODS: The fliC, fimH, and csgA genes by UPEC strain were disrupted by allelic replacement. Flagella, type I fimbriae, and curli were visualized by transmission electron microscopy (TEM). HTB-5 (upper chamber) and HMC-1 (lower chamber) cells cocultured in Transwell® plates were infected with these UPEC strains and purified proteins. There was adherence to HTB-5 cells treated with different UPEC strains and they were quantified as colony-forming units (CFU)/mL. RESULTS: High concentrations of IL-6 and IL-8 were induced by the FimH and FliC proteins; however, these cytokines were detected in low concentrations in presence of CsgA. Compared with UPEC CFT073, CFT073ΔfimH, CFT073ΔfimHΔfliC, and CFT073ΔcsgAΔfimH strains significantly reduced the adherence to HTB-5 cells. CONCLUSION: The FimH and FliC proteins are involved in IL-6 and IL-8 release in a coculture model of HTB-5 and HMC-1 cells.

Chikungunya nsP4 homology modeling reveals a common motif with Zika and Dengue RNA polymerases as a potential therapeutic target.

Among the diseases transmitted by vectors, there are those caused by viruses named arboviruses (arthropod-borne viruses). In past years, viruses transmitted by mosquitoes have been of relevance in global health, such as Chikungunya (CHIKV), Dengue (DENV), and Zika (ZIKV), which have Aedes aegypti as a common vector, thus raising the possibility of multi-infection. Previous reports have described the general structure of RNA-dependent RNA polymerases termed right-hand fold, which is conserved in positive single-stranded RNA viruses. Here, we report a comparison between sequences and the computational structure of RNA-dependent RNA polymerases from CHIKV, DENV, and ZIKV and the conserved sites to be considered for the design of an antiviral drug against the three viruses. We show that the sequential identity between consensus sequences from CHIKV and DENV is 8.1% and the similarity is 15.1%; the identity between CHIKV and ZIKV is 9.3%, and the similarity is 16.6%; and the identity between DENV and ZIKV is 68.6%, and the similarity is 79.2%. Nevertheless, the structural alignment shows that the root-mean-square deviation (RMSD) measurement value in general structure comparison between CHIKV RdRp and ZIKV RdRp was 1.248 Å, RMSD between CHIKV RdRp and DENV RdRp was 1.070 Å, and RMSD between ZIKV RdRp and DENV RdRp was 1.106 Å. Despite the low identity and similarity of CHIKV sequence with DENV and ZIKV, we show that A, B, C, and E motifs are structurally well conserved. These structural similarities offer a window into drug design against these arboviruses giving clues about critical target sites.

|Isolation and characterization of novel bacteriophages as a potential therapeutic option for Escherichia coli urinary tract infections.

Urinary tract infections (UTIs) are mainly caused by uropathogenic Escherichia coli (UPEC), whose impact can be exacerbated by multidrug-resistant (MDR) strains. Effective control strategies are, therefore, urgently needed. Among them, phage therapy represents a suitable alternative. Here, we describe the isolation and characterization of novel phages from wastewater samples, as well as their lytic activity against biofilm and adherence of UPEC to HEp-2 cells. The results demonstrated that phage vB_EcoM-phiEc1 (ϕEc1) belongs to Myoviridae family, whereas vB_EcoS-phiEc3 (ϕEc3) and vB_EcoS-phiEc4 (ϕEc4) belong to Siphoviridae family. Phages showed lytic activity against UPEC and gut commensal strains. Phage ϕEc1 lysed UPEC serogroups, whereas phages ϕEc3 and ϕEc4 lysed only UTI strains with higher prevalence toward the O25 serogroup. Moreover, phages ϕEc1 and ϕEc3 decreased both biofilm formation and adherence, whereas ϕEc4 was able to decrease adherence but not biofilm formation. In conclusion, these novel phages showed the ability to decrease biofilm and bacterial adherence, making them promising candidates for effective adjuvant treatment against UTIs caused by MDR UPEC strains. KEY POINTS: Phage with lytic activity against MDR UPEC strains were isolated and characterized under in vitro conditions. A novel method was proposed to evaluate phage activity against bacterial adherence in HEp-2 cell.. Phages represent a suitable strategy to control infections caused by MDR bacteria.

Molecular Characterization of Staphylococcus aureus Obtained from Blood Cultures of Paediatric Patients Treated in a Tertiary Care Hospital in Mexico.

PURPOSE: Staphylococcus aureus is one of the main causative agents of hospital-acquired (HA) infections. In Mexico, information about the characteristics of clinical S. aureus isolates is limited. Our aim was to characterize S. aureus strains obtained from blood cultures of paediatric patients treated in a tertiary care hospital. MATERIALS AND METHODS: We analysed 249 S. aureus isolates over the period from 2006 to 2019, and their resistance profiles were determined. The isolates were classified into methicillin-resistant S. aureus (MRSA) or methicillin-sensitive S. aureus (MSSA). Staphylococcal cassettes chromosome mec (SCCmec) were detected. Virulence genes (cna, clfA, clfB, eta, etb, fnbA, fnbB, hla, pvl, sec, and tsst) were amplified, and their clonal relationships were established by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and clonal complex (CC) typing. We reviewed one hundred medical files to collect clinical information. RESULTS: Thirty-eight percent of the isolates were MRSA and showed an expanded profile of resistance to other non-beta-lactam antibiotics, while MSSA strains presented a reduced resistance profile. SCCmec-II was the most frequent element (86.3%). Eight virulence factors were detected in MSSA and six in MRSA. The pvl gene was detected in four MRSA-SCCmec-IV isolates (P≤0.0001). MRSA isolates were distributed among 14 clones and were classified into 15 sequence types (ST); the most frequent was ST1011 (17%). The most common CC in MRSA was CC5 (69%, P≤0.0001), and in MSSA, it was CC30 (30%, P≤0.0001). Eighty-seven percent of MRSA isolates were HA-MRSA, and 13% were community-acquired MRSA (CA-MRSA). Of 21 HA-MRSA isolates, 17 had SCCmec-II, while two CA-MRSA isolates had SCCmec-IV. Of MSSA isolates, 77% were derived from HA infections and 23% from CA infections. CONCLUSION: MSSA isolates had more virulence factors. MRSA isolates were resistant to more non-beta-lactam antibiotics, and those with SCCmec-IV expressed a greater variety of virulence factors. Most S. aureus isolates belonged to CC5.

Molecular Epidemiology and Antimicrobial Resistance of Clostridioides difficile in Hospitalized Patients From Mexico.

Clostridioides difficile is a global public health problem, which is a primary cause of antibiotic-associated diarrhea in humans. The emergence of hypervirulent and antibiotic-resistant strains is associated with the increased incidence and severity of the disease. There are limited studies on genomic characterization of C. difficile in Latin America. We aimed to learn about the molecular epidemiology and antimicrobial resistance in C. difficile strains from adults and children in hospitals of México. We studied 94 C. difficile isolates from seven hospitals in Mexico City from 2014 to 2018. Whole-genome sequencing (WGS) was used to determine the genotype and examine the toxigenic profiles. Susceptibility to antibiotics was determined by E-test. Multilocus sequence typing (MLST) was used to determine allelic profiles. Results identified 20 different sequence types (ST) in the 94 isolates, mostly clade 2 and clade 1. ST1 was predominant in isolates from adult and children. Toxigenic strains comprised 87.2% of the isolates that were combinations of tcdAB and cdtAB (tcdA+/tcdB+/cdtA+/cdtB+, followed by tcdA+/tcdB+/cdtA-/cdtB-, tcdA-/tcdB+/cdtA-/ cdtB-, and tcdA-/tcdB-/cdtA+/cdtB+). Toxin profiles were more diverse in isolates from children. All 94 isolates were susceptible to metronidazole and vancomycin, whereas a considerable number of isolates were resistant to clindamycin, fluroquinolones, rifampicin, meropenem, and linezolid. Multidrug-resistant isolates (≥3 antibiotics) comprised 65% of the isolates. The correlation between resistant genotypes and phenotypes was evaluated by the kappa test. Mutations in rpoB and rpoC showed moderate concordance with resistance to rifampicin and mutations in fusA substantial concordance with fusidic acid resistance. cfrE, a gene recently described in one Mexican isolate, was present in 65% of strains linezolid resistant, all ST1 organisms. WGS is a powerful tool to genotype and characterize virulence and antibiotic susceptibility patterns.

Virtual screening of approved drugs as potential SARS-CoV-2 main protease inhibitors.

The global emergency caused by COVID-19 makes the discovery of drugs capable of inhibiting SARS-CoV-2 a priority, to reduce the mortality and morbidity of this disease. Repurposing approved drugs can provide therapeutic alternatives that promise rapid and ample coverage because they have a documented safety record, as well as infrastructure for large-scale production. The main protease of SARS-CoV-2 (Mpro) is an excellent therapeutic target because it is critical for viral replication; however, Mpro has a highly flexible active site that must be considered when performing computer-assisted drug discovery. In this work, potential inhibitors of the main protease (Mpro) of SARS-Cov-2 were identified through a docking-assisted virtual screening procedure. A total of 4384 drugs, all approved for human use, were screened against three conformers of Mpro. The ligands were further studied through molecular dynamics simulations and binding free energy analysis. A total of nine currently approved molecules are proposed as potential inhibitors of SARS-CoV-2. These molecules can be further tested to speed the development of therapeutics against COVID-19.

In vitro bactericidal activity of a carbohydrate polymer with zinc oxide for the treatment of chronic wounds.

Introduction. Biological adhesives and effective topical therapeutic agents that improve wound healing are urgently required for the treatment of chronic ulcers. A biodegradable adhesive based on a carbohydrate polymer with zinc oxide (CPZO) was shown to possess anti-inflammatory activity and enhance wound healing, but its bactericidal activity was unknown.Aim. To investigate the bactericidal activity of CPZO against bacteria commonly present as infectious agents in chronic wounds.Methodology. We examined the bactericidal activity of CPZO against three biofilm-producing bacteria (Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa) through three strategies: bacterial suspension, biofilm disruption and in vitro wound biofilm model.Results. In suspension cultures, CPZO had direct, potent bactericidal action against S. aureus within 24 h, whereas E. coli took 7 days to be eliminated. By contrast, P. aeruginosa survived up to 14 days with CPZO. CPZO had biofilm disruption activity against clinical isolates of S. aureus in the anti-biofilm test. Finally, in the in vitro wound biofilm model, CPZO dramatically reduced the bacterial viability of S. aureus and P. aeruginosa.Conclusions. Together with its previously shown anti-inflammatory properties, the bactericidal activity of CPZO gives it the potential to be a first-line therapeutic option for chronic various ulcers and, possibly, other chronic ulcers, preventing or controlling microbial infections, and leading to the healing of such complicated chronic ulcers.

Microscopic characterization of biofilm in mixed keratitis in a novel murine model.

PURPOSE: To report the characterization and analysis of the biofilm formation in mixed keratitis induced by the coinfection of Staphylococcus aureus and Fusarium falciforme in a novel murine model. METHODS: Clinical ocular microbial isolates and female BALB/c mice were used to develop the murine model. Immunosuppression was achieved with cyclophosphamide and methylprednisolone. A corneoscleral lesion was performed with a micro-pocket technique. Mice received an inoculum with a concentration of 1 × 105 conidia of F. falciforme and S. aureus with 1 × 105 UFC/ml. Mice were sacrificed at 72 h after induction of infection, the right eye was enucleated and preserved in 10% formaldehyde to perform the PAS staining. In addition, cuts were obtained for the labeling with the fluorophores propidium iodide and Calcofluor White, and other eye cuts were processed to transmission microscopy. RESULTS: F. falciforme and S. aureus were able to developed mono and mixed biofilm in vitro. Keratitis of F. falciforme, S. aureus and mixed, were established at immunosuppressed mice. Clinical symptoms were observed at murine cornea. Histological analysis by special stains identified bacterial, fungal and mixed biofilm structures at epithelial and stromal level. Extracellular matrix was observed surrounded clusters of bacterial, fungi and mixed by fluorescence and transmission electronic microscopy. CONCLUSION: This study provides direct evidence of the establishment and formation of mixed biofilm in vitro, as well as in vivo on the corneal surface of mice in an experimentally induced S. aureus and F. falciforme mixed keratitis infection.

Stability of retroviral pseudotypes carrying the hemagglutinin of avian influenza viruses under various storage conditions.

Retroviral pseudotypes are broadly used as safe instruments to mimic the structure and surface of highly pathogenic viruses. They have been employed for the discovery of new drugs, as diagnostic tools in vaccine studies, and part of serological assays. Because of their widespread use in research and their potential as tools for quality control, it is important to know their shelf life, stability, and best storage conditions. In this study, we produced pseudotypes carrying the lacZ reporter gene and the hemagglutinin (HA) of avian influenza virus subtypes H5 and H7 to investigate their stability under various storage conditions. We produced pseudotypes with titers of approximately 106 RLU/mL, which decreased to 105-106 RLU/mL after short-term storage at 4 °C (up to 4 weeks). Stability was maintained after long-term storage at -20 °C (up to 12 months), even under storage variations such as freeze-thaw cycles. We conclude that, although the titers decreased by 1 log10 under the different storage conditions, the remaining titers can be readily applicable in many techniques, such as neutralization assays. These findings show that large quantities of retroviral pseudotypes can be safely stored for short- or long-term use, allowing standardization and reduced variation in assays involving retroviral pseudotypes.

Proteomic changes in a childhood acute lymphoblastic leukemia cell line during the adaptation to vincristine / Cambios en el proteoma de una línea celular de leucemia linfoblástica aguda infantil durante la adaptación a vincristina

Abstract: Introduction: Relapse occurs in approximately 20% of Mexican patients with childhood acute lymphoblastic leukemia (ALL). In this group, chemoresistance may be one of the biggest challenges. An overview of complex cellular processes like drug tolerance can be achieved with proteomic studies. Methods: The B-lineage pediatric ALL cell line CCRF-SB was gradually exposed to the chemotherapeutic vincristine until proliferation was observed at 6 nM, control cells were cultured in the absence of vincristine. The proteome from each group was analyzed by nanoHPLC coupled to an ESI-ion trap mass spectrometer. The identified proteins were grouped into over-represented functional categories with the PANTHER classification system. Results: We found 135 proteins exclusively expressed in the presence of vincristine. The most represented functional categories were: Toll receptor signaling pathway, Ras Pathway, B and T cell activation, CCKR signaling map, cytokine-mediated signaling pathway, and oxidative phosphorylation. Conclusions: Our study indicates that signal transduction and mitochondrial ATP production are essential during adaptation of leukemic cells to vincristine, these processes represent potential therapeutic targets.

Resumen: Introducción: Aproximadamente el 20% de los pacientes mexicanos con leucemia linfoblástica aguda (LLA) infantil presentan recaídas. En este grupo, la quimiorresistencia es uno de los principales desafíos. Los estudios proteómicos pueden dar un panorama general de procesos celulares complejos como la tolerancia a fármacos. Métodos: La línea celular de LLA de linaje B, CCRF-SB, fue expuesta de manera gradual al fármaco quimioterapéutico vincristina hasta observar proliferación celular en presencia de 6 nM, como control se cultivaron células en ausencia del fármaco. Se analizó el proteoma de cada grupo mediante nanoHPLC acoplado a un espectrómetro de masas de tipo trampa de iones. Las proteínas identificadas se agruparon en categorías funcionales sobre-representadas con el sistema de clasificación PANTHER. Resultados: Encontramos 135 proteínas expresadas exclusivamente en presencia de vincristina. Las categorías funcionales más representadas fueron la señalización asociada a los receptores tipo Toll, señalización dependiente de Ras, activación de células B y T, mapa de señalización CCKR, señalización mediada por citoquinas y la fosforilación oxidativa. Conclusiones: Nuestro estudio indica que la transducción de señales y la producción de ATP mitocondrial son procesos esenciales durante la adaptación de células leucémicas a vincristina por lo que estos procesos representan potenciales blancos terapéuticos.

Characterization of Escherichia coli causing community acquired urinary tract infections in Mexico City.

The O25-ST131 clone was identified within 169 uropathogenic Escherichia coli (UPEC) strains. The 44.8% of the 29 O25-ST131 clones detected were positive to least to one extended-spectrum ß-lactamase gene. The phylogroup D was mainly found. The O25-ST131 clone appeared to be associated with community-acquired UTI in Mexico City.

Proteomic changes in a childhood acute lymphoblastic leukemia cell line during the adaptation to vincristine.

INTRODUCTION: Relapse occurs in approximately 20% of Mexican patients with childhood acute lymphoblastic leukemia (ALL). In this group, chemoresistance may be one of the biggest challenges. An overview of complex cellular processes like drug tolerance can be achieved with proteomic studies. METHODS: The B-lineage pediatric ALL cell line CCRF-SB was gradually exposed to the chemotherapeutic vincristine until proliferation was observed at 6nM, control cells were cultured in the absence of vincristine. The proteome from each group was analyzed by nanoHPLC coupled to an ESI-ion trap mass spectrometer. The identified proteins were grouped into overrepresented functional categories with the PANTHER classification system. RESULTS: We found 135 proteins exclusively expressed in the presence of vincristine. The most represented functional categories were: Toll receptor signaling pathway, Ras Pathway, B and T cell activation, CCKR signaling map, cytokine-mediated signaling pathway, and oxidative phosphorylation. CONCLUSIONS: Our study indicates that signal transduction and mitochondrial ATP production are essential during adaptation of leukemic cells to vincristine, these processes represent potential therapeutic targets.

Detección de la Beta lactamasa de espectro OXA-141 en cepas de Pseudomonas aeruginosa aisladas de pacientes con fibrosis quística / No disponible

Introducción: Los objetivos de este trabajo fueron estudiar la presencia de -lactamasas de espectro extendido (BLEE), investigar la ubicación de los genes que codifican para esas enzimas y determinar la relación clonal de cepas de Pseudomonas aeruginosa resistentes a la ceftazidima aisladas de pacientes mexicanos con fibrosis quística. Metodología: Se determinó el perfil de resistencia a 11 antibióticos (CLSI) y la detección fenotípica de las BLEE siguiendo un método de difusión en discos de papel filtro adaptado para P. aeruginosa. La caracterización de los genes de las BLEE y de integrones se realizó por PCR y secuenciación del ADN, mientras que el análisis de la relación clonal se realizó por PFGE. Resultados: De las 148 cepas en estudio, 22 resultaron resistentes a la ceftazidima y el análisis por PCR y secuenciación reveló la presencia del genblaOXA-141 en 7 cepas, 6 resistentes y una sensible a la ceftazidima. Asimismo, blaGES se detectó en 11 cepas. Los genes intI2 e intI3 no se detectaron por PCR, pero en las 6cepas resistentes a la ceftazidima se descubrió el gen blaOXA-141 en un integrón de la clase 1. El análisis de la relación clonal de los aislamientos mostró que la mayoría de los pacientes se infectaron a lo largo del periodo de estudio con cepas de P. aeruginosa que presentaron patrones diferentes, principalmente en los individuos que no tenían relación familiar. Conclusiones: Este trabajo demuestra la existencia del gen blaOXA-141 asociado a un integrón de clase 1 en varias cepas de P. aeruginosa, así como de genes blaGES cuya localización y variante están en estudio en el grupo de investigación. Lo anterior, aunado a la diversidad de cepas capaces de infectar a individuos sensibles, sugiere un riesgo de dispersión de las cepas de P. aeruginosa productoras de BLEE entre la población mexicana que padece fibrosis quística (AU)

Introduction: The aims of this research were to study the presence of extended spectrum -lactamases(ESBL) to investigate the location of the genes encoding these enzymes, and determine the clonal relationship of strains of ceftazidime-resistant Pseudomonas aeruginosa isolated from Mexican patients with cystic fibrosis. Methods: We determined the resistance profile to 11 antibiotics (CLSI) and phenotypic ESBL detection following a disk diffusion method adapted for P. aeruginosa. Characterization of ESBL genes and integrons was performed by polymerase chain reaction (PCR) and DNA sequencing, while analysis of the clonal relationship was performed by pulsed field gel electrophoresis (PFGE) Results: Of the 148 strains studied, 22 were resistant to ceftazidime, and analysis by PCR and sequencing revealed the presence of the gene blaOXA-141 in 7 strains, 6 of which were resistant and one, susceptible to ceftazidime. In addition, blaGES was detected in 11 strains. intI2 and intI3 genes were not detected byPCR, but in the 6 ceftazidime-resistant strains, the blaOXA-141 gene was determined in a class 1 integron. Analysis of the clonal relationship of isolates showed that the majority of patients were infected during the study period with P. aeruginosa strains that exhibit different patterns, especially in individuals without a familial relationship. Conclusions: This report demonstrates the existence of the blaOXA-141 gene associated with a class 1 integron in several strains of P. aeruginosa, as well as blaGES genes, and their location and variants are being studied by our research group. This, combined with the diversity of strains able to infect several susceptible individuals, suggests the risk of spread of P. aeruginosa-strain ESBL producers among Mexican populations with cystic fibrosis (AU)

Unusual diversity of acquired ß-lactamases in multidrug-resistant Pseudomonas aeruginosa isolates in a Mexican hospital.

AIMS: To investigate the presence of extended spectrum and metallo ß-lactamases (MBLs) in Pseudomonas aeruginosa isolates which are resistant to imipenem and ceftazidime that were isolated in a hospital in Mexico. RESULTS: Pulsed-field gel electrophoresis (PFGE) revealed the presence of four clonal types among the 14 isolates. All these genes were found either alone or simultaneously in the P. aeruginosa strains in the following five different arrangements: ; ; ; ; and . Class 1 integrons were detected and contained the cassettes bla(GES-5) and bla(OXA-2), but not that of bla(VIM). bla(VIM) genes occurred only in the chromosome, while bla(GES-5) was located in the chromosome and in the plasmids. CONCLUSIONS: To our knowledge, this is the first description of P. aeruginosa strains simultaneously producing the VIM-2 and VIM-11 variants, and the combination of GES-5 and MBL carbapenemases, which determines a major challenge for the clinical microbiology laboratory and a remarkable epidemiological risk for the nosocomial spread of multidrug-resistant determinants.