Yolanda López-Vidal - Academia.edu (original) (raw)
Papers by Yolanda López-Vidal
Research in Microbiology, Jun 1, 2019
PubMed, Jun 3, 1998
Objective: To estimate the frequency of H. pylori clinical isolates resistant to six commonly use... more Objective: To estimate the frequency of H. pylori clinical isolates resistant to six commonly used antimicrobials. Design: Cross-sectional observational study. Setting: A tertiary-referral health care institution in Mexico City. Participants: 31 isolates of H. pylori from 31 patients with chronic antral gastritis were obtained from gastric mucosal biopsy specimens. Main outcome measure: The Minimum Inhibitory Concentration (MIC) to ampicillin, amoxycillin, tetracycline, doxycycline, metronidazole and to colloidal bismuth subcitrate was determined by the agar plate dilution test. Results: All isolates showed to be susceptible to the former four antibiotics but only in 46% and 55% growth was inhibited by 8 micrograms/mL and 16 micrograms/mL of metronidazole, respectively. All isolates were inhibited by < or = 128 micrograms/mL of bismuth. A 50% increase in the percentage of metronidazole-resistant isolates (MIC > or = 8 micrograms/mL) between 1988 to 1992 was observed. Conclusion: There is a need of future studies in our setting aimed at assessing the cost/effectiveness of diverse H. pylori-associated peptic ulcer treatment options.
Journal of Clinical Microbiology, Oct 1, 1988
PubMed, 2009
A systematic review of published articles was performed to identify risk factors associated with ... more A systematic review of published articles was performed to identify risk factors associated with recent transmission of tuberculosis (TB). The computerized search identified studies in PubMed, Ovid, CDSR, CINAHL and EMBASE published between 1994 and 2005. Of 137 articles, 30 satisfied all the inclusion criteria for meta-analysis. A random effects model estimated the odds ratio (OR), confidence interval (CI), and heterogeneity between studies. Recent transmission of TB was associated with: ethnic minority (OR 3.03, 95%CI 2.21- 4.16), being a native of the country (OR 2.33, 95%CI 1.76-3.08), residing in an urban area (OR 1.52, 95%CI 1.35-1.72), drug use (OR 3.01, 95%CI 2.14-4.22), excessive alcohol consumption (OR 2.27, 95%CI 1.69-3.06), homelessness (OR 2.87, 95%CI 2.04-4.02), previous incarceration (OR 2.21, 95%CI 1.71-2.86), human immunodeficiency virus infection/acquired immune-deficiency syndrome (OR 1.66, 95%CI 1.36-2.05), young age (OR 2.09, 95%CI 1.69-2.59), sputum smear positivity (OR 1.39, 95%CI 1.20-1.60) and male sex (OR 1.37, 95%CI 1.19-1.58). The results should be useful for improving prevention and control strategies, thus contributing to a reduction in Mycobacterium tuberculosis transmission.
Geohealth, Jun 1, 2023
The factors influencing the incidence of COVID‐19, including the impact of the vaccination progra... more The factors influencing the incidence of COVID‐19, including the impact of the vaccination programs, have been studied in the literature. Most studies focus on one or two factors, without considering their interactions, which is not enough to assess a vaccination program in a statistically robust manner. We examine the impact of the U.S. vaccination program on the SARS‐CoV‐2 positivity rate while simultaneously considering a large number of factors involved in the spread of the virus and the feedbacks among them. We consider the effects of the following sets of factors: socioeconomic factors, public policy factors, environmental factors, and non‐observable factors. A time series Error Correction Model (ECM) was used to estimate the impact of the vaccination program at the national level on the positivity rate. Additionally, state‐level ECMs with panel data were combined with machine learning techniques to assess the impact of the program and identify relevant factors to build the best‐fitting models. We find that the vaccination program reduced the virus positivity rate. However, the program was partially undermined by a feedback loop in which increased vaccination led to increased mobility. Although some external factors reduced the positivity rate, the emergence of new variants increased the positivity rate. The positivity rate was associated with several forces acting simultaneously in opposite directions such as the number of vaccine doses administered and mobility. The existence of complex interactions, between the factors studied, implies that there is a need to combine different public policies to strengthen the impact of the vaccination program.
Clinical & Developmental Immunology, 2011
Journal of Clinical Microbiology, Oct 1, 1986
![Research paper thumbnail of [Biochemical characterization of Campylobacter using the "Micro Campy" method]](https://attachments.academia-assets.com/120661118/thumbnails/1.jpg)
](PubMed, May 1, 1994
Three species of Campylobacter are recognized as enteropathogens in children under five years of ... more Three species of Campylobacter are recognized as enteropathogens in children under five years of age and in immunocompromised patients. Several groups have tried to classify them using biochemical profiles and have found six different patterns which comprise 12 individual tests. We have designed a "Micro Campy" method which identifies C. jejuni, C. coli and C. lari classifying them into several biotypes. Fifty two Campylobacter strains isolated from humans were studied and classified in 24 different patterns. Strains isolated from diarrhea episodes were seen in two specific patterns. We propose the use of this easy to perform method which has a reproducibility higher than 92% in biotyping Campylobacter strains.
Gaceta Medica De Mexico, Jul 1, 2005
The global warming our generation is experiencing is just one of the great environmental crises o... more The global warming our generation is experiencing is just one of the great environmental crises of the Anthropocene, a geological period that began with the use of fossil fuels and that, in merely one century and a few decades of industrial activity, has altered ecosystemic processes that sustain human health and well-being. Beyond the loss of the “intrinsic value of nature”, changes in the magnitude and direction of biogeochemical cycles and increases in temperature are phenomena that not only accompany the loss of habitats and species but impair resilience by ultimately generating greater and more complex numbers and types of exposures that constitute a danger to human health. In this study, we attempted to offer some notes about the margin, understood as that space with the greatest inequity and therefore the fastest growth of risk: the collision area where deprivation marks the social determinants of health and where the greatest interaction with causes of disease occur.
Frontiers in Cellular and Infection Microbiology, Feb 13, 2023
Revista de la Facultad de Medicina, Sep 10, 2022
According to the World Health Organization (WHO), 3.58 billion people were affected by oral disor... more According to the World Health Organization (WHO), 3.58 billion people were affected by oral disorders, where caries, followed by periodontal disease are the most frequent and the main causes of damage to pulp tissue and loss of dental organs. In Mexico, the Epidemiological Surveillance System for Oral Pathologies (SIVEPAB) reported that 53% of the population is affected by some degree of periodontal disease, while on average caries affects 93.3% of the population between 20 and 85 years old and older, as well as about 50.0% of children and adolescents, so both conditions are considered an important public health problem in this country. Additionally, the human oral microbiome is known to be associated with oral health and disease. An imbalance in the oral microbiome (dysbiosis) can result in the proliferation of Streptococcus mutans and Porphyromonas gingivalis, linked to caries and periodontal disease. The latter two conditions, the most prevalent oral diseases worldwide, are the main causes of damage to pulp tissue and loss of dental organs. In the presence of these pathologies, constant exposure to the corresponding inflammatory chronic infection could lead to the translocation of oral bacteria to other parts of the body, where they may contribute to the development and/or exacerbation of systemic inflammation and trigger disease. Since age, diet, genetics, and geographical location are known to influence the variability of the human microbiome, it is important to analyze differences in the oral microbiome between distinct populations. Up to now, little attention has been given to this task. The current review carried out for articles published between 2010 and 2020 and describes the human oral microbiome in populations of Asia, Africa, America and Europa, to explore whether geographical differences have an impact on the variability of the human oral microbiome. Keywords: Human oral microbiome; oral microbiota; geography; health and sickness.
Bioresource Technology, May 1, 2001
LA DIARREA INFANTIL AGUDA CAUSADA POR LA BACTERIA ENTEROTOXIGENICA PODRIA DEJAR DE OCASIONAR ESTR... more LA DIARREA INFANTIL AGUDA CAUSADA POR LA BACTERIA ENTEROTOXIGENICA PODRIA DEJAR DE OCASIONAR ESTRAGOS ENTRE LA POBLACION PEDIATRICA DE AMERICA LATINA, ASIA Y AFRICA, CON UNA VACUNA INTRANASAL PEPTIDICA CREADA EN LA UNAM.
Water Science and Technology, 2000
Diesel, toluene and naphthalene-degrading microbial consortia were isolated from a diesel-contami... more Diesel, toluene and naphthalene-degrading microbial consortia were isolated from a diesel-contaminated soil. The presence of catabolic genes, xylE and ndoB responsible for toluene/xylene and naphthalene biodegradation, respectively, were screened by PCR techniques in all microbial consortia. The diesel-consortium possessed both catabolic genes, the toluene-consortium only the xylE gene, while the naphthalene-consortium possessed only the ndoB gene. On the basis of these results, it was concluded that contaminated soil has indigenous microbes with a high natural potential for biodegradation.
Research in Microbiology, Jun 1, 2019
PubMed, Jun 3, 1998
Objective: To estimate the frequency of H. pylori clinical isolates resistant to six commonly use... more Objective: To estimate the frequency of H. pylori clinical isolates resistant to six commonly used antimicrobials. Design: Cross-sectional observational study. Setting: A tertiary-referral health care institution in Mexico City. Participants: 31 isolates of H. pylori from 31 patients with chronic antral gastritis were obtained from gastric mucosal biopsy specimens. Main outcome measure: The Minimum Inhibitory Concentration (MIC) to ampicillin, amoxycillin, tetracycline, doxycycline, metronidazole and to colloidal bismuth subcitrate was determined by the agar plate dilution test. Results: All isolates showed to be susceptible to the former four antibiotics but only in 46% and 55% growth was inhibited by 8 micrograms/mL and 16 micrograms/mL of metronidazole, respectively. All isolates were inhibited by < or = 128 micrograms/mL of bismuth. A 50% increase in the percentage of metronidazole-resistant isolates (MIC > or = 8 micrograms/mL) between 1988 to 1992 was observed. Conclusion: There is a need of future studies in our setting aimed at assessing the cost/effectiveness of diverse H. pylori-associated peptic ulcer treatment options.
Journal of Clinical Microbiology, Oct 1, 1988
PubMed, 2009
A systematic review of published articles was performed to identify risk factors associated with ... more A systematic review of published articles was performed to identify risk factors associated with recent transmission of tuberculosis (TB). The computerized search identified studies in PubMed, Ovid, CDSR, CINAHL and EMBASE published between 1994 and 2005. Of 137 articles, 30 satisfied all the inclusion criteria for meta-analysis. A random effects model estimated the odds ratio (OR), confidence interval (CI), and heterogeneity between studies. Recent transmission of TB was associated with: ethnic minority (OR 3.03, 95%CI 2.21- 4.16), being a native of the country (OR 2.33, 95%CI 1.76-3.08), residing in an urban area (OR 1.52, 95%CI 1.35-1.72), drug use (OR 3.01, 95%CI 2.14-4.22), excessive alcohol consumption (OR 2.27, 95%CI 1.69-3.06), homelessness (OR 2.87, 95%CI 2.04-4.02), previous incarceration (OR 2.21, 95%CI 1.71-2.86), human immunodeficiency virus infection/acquired immune-deficiency syndrome (OR 1.66, 95%CI 1.36-2.05), young age (OR 2.09, 95%CI 1.69-2.59), sputum smear positivity (OR 1.39, 95%CI 1.20-1.60) and male sex (OR 1.37, 95%CI 1.19-1.58). The results should be useful for improving prevention and control strategies, thus contributing to a reduction in Mycobacterium tuberculosis transmission.
Geohealth, Jun 1, 2023
The factors influencing the incidence of COVID‐19, including the impact of the vaccination progra... more The factors influencing the incidence of COVID‐19, including the impact of the vaccination programs, have been studied in the literature. Most studies focus on one or two factors, without considering their interactions, which is not enough to assess a vaccination program in a statistically robust manner. We examine the impact of the U.S. vaccination program on the SARS‐CoV‐2 positivity rate while simultaneously considering a large number of factors involved in the spread of the virus and the feedbacks among them. We consider the effects of the following sets of factors: socioeconomic factors, public policy factors, environmental factors, and non‐observable factors. A time series Error Correction Model (ECM) was used to estimate the impact of the vaccination program at the national level on the positivity rate. Additionally, state‐level ECMs with panel data were combined with machine learning techniques to assess the impact of the program and identify relevant factors to build the best‐fitting models. We find that the vaccination program reduced the virus positivity rate. However, the program was partially undermined by a feedback loop in which increased vaccination led to increased mobility. Although some external factors reduced the positivity rate, the emergence of new variants increased the positivity rate. The positivity rate was associated with several forces acting simultaneously in opposite directions such as the number of vaccine doses administered and mobility. The existence of complex interactions, between the factors studied, implies that there is a need to combine different public policies to strengthen the impact of the vaccination program.
Clinical & Developmental Immunology, 2011
Journal of Clinical Microbiology, Oct 1, 1986
PubMed, May 1, 1994
Three species of Campylobacter are recognized as enteropathogens in children under five years of ... more Three species of Campylobacter are recognized as enteropathogens in children under five years of age and in immunocompromised patients. Several groups have tried to classify them using biochemical profiles and have found six different patterns which comprise 12 individual tests. We have designed a "Micro Campy" method which identifies C. jejuni, C. coli and C. lari classifying them into several biotypes. Fifty two Campylobacter strains isolated from humans were studied and classified in 24 different patterns. Strains isolated from diarrhea episodes were seen in two specific patterns. We propose the use of this easy to perform method which has a reproducibility higher than 92% in biotyping Campylobacter strains.
Gaceta Medica De Mexico, Jul 1, 2005
The global warming our generation is experiencing is just one of the great environmental crises o... more The global warming our generation is experiencing is just one of the great environmental crises of the Anthropocene, a geological period that began with the use of fossil fuels and that, in merely one century and a few decades of industrial activity, has altered ecosystemic processes that sustain human health and well-being. Beyond the loss of the “intrinsic value of nature”, changes in the magnitude and direction of biogeochemical cycles and increases in temperature are phenomena that not only accompany the loss of habitats and species but impair resilience by ultimately generating greater and more complex numbers and types of exposures that constitute a danger to human health. In this study, we attempted to offer some notes about the margin, understood as that space with the greatest inequity and therefore the fastest growth of risk: the collision area where deprivation marks the social determinants of health and where the greatest interaction with causes of disease occur.
Frontiers in Cellular and Infection Microbiology, Feb 13, 2023
Revista de la Facultad de Medicina, Sep 10, 2022
According to the World Health Organization (WHO), 3.58 billion people were affected by oral disor... more According to the World Health Organization (WHO), 3.58 billion people were affected by oral disorders, where caries, followed by periodontal disease are the most frequent and the main causes of damage to pulp tissue and loss of dental organs. In Mexico, the Epidemiological Surveillance System for Oral Pathologies (SIVEPAB) reported that 53% of the population is affected by some degree of periodontal disease, while on average caries affects 93.3% of the population between 20 and 85 years old and older, as well as about 50.0% of children and adolescents, so both conditions are considered an important public health problem in this country. Additionally, the human oral microbiome is known to be associated with oral health and disease. An imbalance in the oral microbiome (dysbiosis) can result in the proliferation of Streptococcus mutans and Porphyromonas gingivalis, linked to caries and periodontal disease. The latter two conditions, the most prevalent oral diseases worldwide, are the main causes of damage to pulp tissue and loss of dental organs. In the presence of these pathologies, constant exposure to the corresponding inflammatory chronic infection could lead to the translocation of oral bacteria to other parts of the body, where they may contribute to the development and/or exacerbation of systemic inflammation and trigger disease. Since age, diet, genetics, and geographical location are known to influence the variability of the human microbiome, it is important to analyze differences in the oral microbiome between distinct populations. Up to now, little attention has been given to this task. The current review carried out for articles published between 2010 and 2020 and describes the human oral microbiome in populations of Asia, Africa, America and Europa, to explore whether geographical differences have an impact on the variability of the human oral microbiome. Keywords: Human oral microbiome; oral microbiota; geography; health and sickness.
Bioresource Technology, May 1, 2001
LA DIARREA INFANTIL AGUDA CAUSADA POR LA BACTERIA ENTEROTOXIGENICA PODRIA DEJAR DE OCASIONAR ESTR... more LA DIARREA INFANTIL AGUDA CAUSADA POR LA BACTERIA ENTEROTOXIGENICA PODRIA DEJAR DE OCASIONAR ESTRAGOS ENTRE LA POBLACION PEDIATRICA DE AMERICA LATINA, ASIA Y AFRICA, CON UNA VACUNA INTRANASAL PEPTIDICA CREADA EN LA UNAM.
Water Science and Technology, 2000
Diesel, toluene and naphthalene-degrading microbial consortia were isolated from a diesel-contami... more Diesel, toluene and naphthalene-degrading microbial consortia were isolated from a diesel-contaminated soil. The presence of catabolic genes, xylE and ndoB responsible for toluene/xylene and naphthalene biodegradation, respectively, were screened by PCR techniques in all microbial consortia. The diesel-consortium possessed both catabolic genes, the toluene-consortium only the xylE gene, while the naphthalene-consortium possessed only the ndoB gene. On the basis of these results, it was concluded that contaminated soil has indigenous microbes with a high natural potential for biodegradation.