Métodos y técnicas de monitoreo y predicción temprana en los escenarios de riesgos socionaturales

Esta obra concentra los métodos y las técnicas fundamentales para el seguimiento y monitoreo de las dinámicas de los escenarios de riesgos socionaturales (geológicos e hidrometeorológicos) y tiene como objetivo general orientar, apoyar y acompañar a los directivos y operativos de protección civil en aterrizar las acciones y políticas públicas enfocadas a la gestión del riesgo local de desastre

Methicillin-resistant S. aureus colonization in Mexican children attending day care centres

Purpose: To determine MRSA carriage rates and genetic relationships of S. aureus strains in children attending day care centres in 14 cities from three geographic regions in Mexico. Materials and methods: Cross-Sectional Study performed in apparently healthy children aged from 6 mo to 6 yr attending day care centres (DCCs). From September 2002 To January 2003, 2345 nasopharyngeal specimens from a similar number of children were collected. Nasopharyngeal samples for bacterial isolation were obtained by standard methods. Antimicrobial susceptibility was determined and genetic relatedness of all MRSA isolates was determined by pulsed field gel electrophoresis (PFGE). Results: S. aureus was identified in 237 children (10.1%), twenty-two children had MSRA for an overall prevalence of MRSA carriage of 0.93%. Children attending DCCs from cities located in the north and south of Mexico showed higher prevalence than children from DCCs in the central region; 1.75%, and 1.71 vs. 0.08%, respectively (P < 0.05). PFGE demonstrated six different restriction profiles of MRSA with a predominant pattern. Conclusions: We documented the presence of MRSA strain colonizing children attending DCCs in Mexico, mainly in the south and north regions of the country. Clone A and B which are closely related represented 45 % of the total of MRSA isolates. We found both, SCCmec type II and type IV strains in the three regions

In Vitro Probiotic Potential of Lactic Acid Bacteria Isolated from Aguamiel and Pulque and Antibacterial Activity Against Pathogens

Probiotics can act as a natural barrier against several pathogens, such Helicobacter pylori, a bacterium linked to stomach cancer. The aim of the present study was to isolate and identify lactic acid bacteria (LAB) from pulque and aguamiel, and evaluate their probiotic potential and antimicrobial effect on Escherichia coli, Staphylococcus aureus, and Helicobacter pylori. Ten isolates were selected and evaluated for in vitro resistance to antibiotics and gastrointestinal conditions, and antimicrobial activity against E. coli and S. aureus and the effect on H. pylori strains. 16S rRNA identification was performed. Ten potential probiotic isolates were confirmed as belonging to the genera Lactobacillus and Pediococcus. All the strains were susceptible to clinical antibiotics, except to vancomycin. Sixty percent of the isolates exhibited antimicrobial activity against E. coli and S. aureus. The growth of H. pylori ATCC 43504 was suppressed by all the LAB, and the urease activity from all the H. pylori strains was inhibited, which may decrease its chances for survival in the stomach. The results suggest that LAB isolated from pulque and aguamiel could be an option to establish a harmless relationship between the host and H. pylori, helping in their eradication therapy

Mechanisms and Applications of Citral’s Antimicrobial Properties in Food Preservation and Pharmaceuticals Formulations

Citral is a monoterpene constituted by two isomers known as neral and geranial. It is present in different plant sources and recognized as safe (GRAS) by the Food and Drug Administration (FDA). In recent years, investigations have demonstrated that this compound exhibited several biological activities, such as antibacterial, antifungal, antibiofilm, antiparasitic, antiproliferative, anti-inflammatory, and antioxidant properties, by in vitro and in vivo assays. Additionally, when incorporated into different food matrices, citral can reduce the microbial load of pathogenic microorganisms and extend the shelf life. This compound has acceptable drug-likeness properties and does not present any violations of Lipinski’s rules, which could be used for drug development. The above shows that citral could be a compound of interest for developing food additives to extend the shelf life of animal and vegetable origin foods and develop pharmaceutical products

Dysbiosis by Eradication of <i>Helicobacter pylori</i> Infection Associated with Follicular Gastropathy and Pangastropathy

Dysbiosis plays an important role in the development of bacterial infections in the gastric mucosa, particularly Helicobacter pylori. The international guidelines for the treatment of H. pylori infections suggest standard triple therapy (STT). Nevertheless, because of the increasing resistance rates to clarithromycin, metronidazole has been widely considered in several countries. Unfortunately, the non-justified administration of antibiotics induces dysbiosis in the target organ. We characterized the gastric microbiota of patients diagnosed with follicular gastropathy and pangastropathy attributed to H. pylori infection, before and after the administration of STT with metronidazole. Dominant relative abundances of Cutibacterium were observed in pre-treatment patients, whereas H. pylori was observed at Cutibacterium acnes and H. pylori with gastric infectious diseases was also evaluated using quantitative real-time polymerase chain reaction. The dominance of C. acnes over H. pylori was observed in gastritis, gastropathies, and non-significant histological alterations. None of the microorganisms were detected in the intestinal metaplasia. Post-treatment alterations revealed an increase in the relative abundances of Staphylococcus, Pseudomonas, and Klebsiella. Non-H. pylori gastrointestinal bacteria can be associated with the initiation and development of gastric diseases, such as pathobiont C. acnes

Role of Helicobacter pylori and Other Environmental Factors in the Development of Gastric Dysbiosis

Microbiomes are defined as complex microbial communities, which are mainly composed of bacteria, fungi, and viruses residing in diverse regions of the human body. The human stomach consists of a unique and heterogeneous habitat of microbial communities owing to its anatomical and functional characteristics, that allow the optimal growth of characteristic bacteria in this environment. Gastric dysbiosis, which is defined as compositional and functional alterations of the gastric microbiota, can be induced by multiple environmental factors, such as age, diet, multiple antibiotic therapies, proton pump inhibitor abuse, H. pylori status, among others. Although H. pylori colonization has been reported across the world, chronic H. pylori infection may lead to serious consequences; therefore, the infection must be treated. Multiple antibiotic therapy improvements are not always successful because of the lack of adherence to the prescribed antibiotic treatment. However, the abuse of eradication treatments can generate gastric dysbiotic states. Dysbiosis of the gastric microenvironment induces microbial resilience, due to the loss of relevant commensal bacteria and simultaneous colonization by other pathobiont bacteria, which can generate metabolic and physiological changes or even initiate and develop other gastric disorders by non-H. pylori bacteria. This systematic review opens a discussion on the effects of multiple environmental factors on gastric microbial communities

Identification of extensive drug resistant Pseudomonas aeruginosa strains: New clone ST1725 and high-risk clone ST233.

Several microorganisms produce nosocomial infections (NIs), among which Pseudomonas aeruginosa stands out as an opportunist pathogen with the capacity to develop multiresistance to first-choice antibiotics. From 2007 to 2013, forty-six NIs produced by P. aeruginosa were detected at a pediatric tertiary care hospital in Mexico with a significant mortality rate (17.39%). All isolates (n = 58/46 patients) were characterized by evaluating their response to several antibiotics as panresistant (PDR), extensively resistant (XDR), multiresistant (MDR) or sensitive (S). In addition, all isolates were typified through multilocus sequencing of seven genes: acsA, aroE, guaA, mutL, nuoD, ppsA and trpE. Furthermore, to establish the genetic relationships among these isolates, we carried out a phylogenetic inference analysis using maximum likelihood to construct a phylogenetic network. To assess evolutionary parameters, recombination was evaluated using the PHI test, and the ratio of nonsynonymous to synonymous substitutions was determined. Two of the strains were PDR (ST1725); 42 were XDR; four were MDR; and ten were S. Twenty-one new sequence types were detected. Thirty-three strains exhibited novel sequence type ST1725. The ratio of nonsynonym to synonym substitutions was 1:1 considering all genes. Phylogenetic analysis showed that the genetic relationship of the PDR, XDR and MDR strains was mainly clonal; however, the PHI test and the phylogenetic network suggest that recombination events occurred to produce a non-clonal population. This study aimed not only to determine the genetic diversity of clinical P. aeruginosa but also to provide a warning regarding the identification and spreading of clone ST1725, its ability to cause outbreaks with high mortality rates, and to remain in the hospital environment for over seven years. These characteristics highlight the need to identify clonal outbreaks, especially where high resistance to most antibiotics is observed, and control measures are needed. This study also represents the first report of the PDR ST1725

Differential expression of miRNA-146a and miRNA-155 in gastritis induced by Helicobacter pylori infection in paediatric patients, adults, and an animal model

Abstract Background Helicobacter pylori is a major aetiologic agent associated with gastritis. H. pylori infections increase the expression of the Toll-like receptor (TLR), which in turn modulates the expression of microRNA (miRNA)-146a and miRNA-155. The objective of this study was to compare the expression of miRNA-146a and miRNA-155 in gastric lesions of paediatric and adult patients with different pathologies and in Mongolian gerbils (Meriones unguiculatus) infected with H. pylori 26,695. Methods Quantification of miRNA expression was performed by quantitative real-time polymerase chain reaction (qRT-PCR) of paraffin-embedded gastric lesions of children with or without an infection (n = 25), adults with follicular gastritis and metaplasia (n = 32) and eight-week-old M. unguiculatus males (Hsd:MON) infected with H. pylori 26,695 for 0, 3, 6, 12 and 18 months (n = 25). The genes RNU48 and RNU6 were used as endogenous controls for data normalization. Statistical analyses were performed using Kruskal-Wallis, Mann-Whitney, ANOVA and Student’s t-test. Results The expression of miRNA-146a and miRNA-155 in infected children increased by 247.6- and 79.4-fold (on average), respectively, compared to that observed in the control group. However, these results were not significant (p = 0.12 and p = 0.07 respectively). In some children a gradual increase in expression was observed, while in others, expression was very high. Additionally, the expression levels of miRNA-146a and miRNA-155 increased by an average of 21.7- and 62-fold, respectively, in adult patients with follicular gastritis when compared to those of the controls. In M. unguiculatus infected with H. pylori 26,695, the expression of both miRNAs increased as the infection progressed. Conclusion This is the first report to show differences in the expression of miRNA-146a and miRNA-155 in paediatric and adult patients with gastritis who were infected with H. pylori. In addition, in M. unguiculatus infected with H. pylori, miRNA expression was associated with the progression of infection and the ability of the bacteria to adapt to the host