Oscar Newton-Sanchez’s research while affiliated with University of Colima and other places

Objective To analyze the resistance to antimicrobials in clinical isolates from pediatric patients in Mexico. Methods Susceptibility data from relevant specimens were collected in the pediatric population over 6 months from 25 centers from 17 states of Mexico and analyzed using the WHONET 5.6 software. Data were stratified into three age groups: younger than 2 years, 2 to 6 years, and 6 to 18 years. Results For Escherichia coli, the infant/toddler group had higher resistance rates to ampicillin, ampicillin-sulbactam, cefuroxime, cefepime, gentamicin, quinolones (p < 0.001), amoxicillin/clavulanic acid (p = 0.003), and ceftazidime (p = 0.004) than the other two age groups. Additionally, a high proportion of extended-spectrum β-lactamase (ESBL)-producing isolates for E. coli (75.3%) was detected in this age group. Comparable results were observed for Klebsiella pneumoniae, with higher resistance to ampicillin-sulbactam, ceftazidime, gentamicin, cefepime, trimethoprim-sulfamethoxazole, carbapenems (p = 0.001) and amoxicillin/clavulanic acid (p = 0.023) in the infant/toddler group. Moreover, a high proportion of ESBL producers (76%) was detected in this age group. Regarding wards, E. coli and K. pneumoniae had the highest carbapenem resistance in the ICU area, and Acinetobacter baumannii had the highest carbapenem resistance in medical wards. Conclusion High antibiotic resistance rates were detected in the infant/toddler group. This report presents baseline data for future prospective surveillance studies of antimicrobial resistance in pediatric patients in Mexico.

Background. Antimicrobial resistance is a global concern. Analysis of sterile fluids is essential because microorganisms are defined as significant in most cases. Blood, cerebrospinal, and pleural fluids are frequently received in the microbiology lab because they are associated with considerable rates of morbi-mortality. Knowledge of epidemiology in these samples is needed to choose proper empirical treatments due to the importance of reducing selection pressure. Methods. We used retrospective laboratory data of blood, CSF, and pleural fluid collected from patients in Mexico between 2019 and 2020. Each laboratory identified the strains and tested susceptibility using its routine methods. For Streptococcus pneumoniae, a comparative analysis was performed with data from the broth microdilution method. Results. Forty-five centers participated in the study, with 30,746 clinical isolates from blood, 2,429 from pleural fluid, and 2,275 from CSF. For blood and CSF, Staphylococcus epidermidis was the most frequent. For blood, among gram negatives, the most frequent was Escherichia coli. Among Enterobacterales, 9.8% of K. pneumoniae were carbapenem-resistant. For S. pneumoniae, similar resistance percentages were observed for levofloxacin, cefotaxime, and vancomycin. For CSF, the most frequent gramnegative was E. coli. In Acinetobacter baumannii, carbapenem resistance was 71.4%. The most frequent species detected for pleural fluid was E. coli; in A. baumannii, carbapenem resistance was 96.3%. Conclusion. Gram-negative bacteria, with E. coli most prevalent, are frequently recovered from CSF, blood, and pleural fluid. In S. pneumoniae, the routine, conventional methods showed good agreement in detecting resistance percentages for erythromycin, levofloxacin, and vancomycin.

Background Stenotrophomonas maltophilia is a non-fermenting Gram-negative pathogen, which causes healthcare-associated infections and exhibits increasing drug resistance rates. In this study, we compared the effect of levofloxacin and trimethoprim-sulfamethoxazole on planktonic and biofilm cells of S. maltophilia isolates obtained from blood and respiratory samples. Methods S. maltophilia isolates were recollected from patients older than 18 years from 2018-2020 from Hospital Universitario Dr. Jose Eleuterio Gonzalez, a tertiary care hospital from Nuevo Leon, Mexico. Bacteria were dentified by MALDI-TOF MS. Biofilm formation was determined using the crystal violet staining method.Antimicrobial susceptibility in planktonic cells and biofilm cells were determined by the broth microdilution and the Calgary device, respectively. Results During the 3-year study period, 44 S. maltophilia isolates were identified, 28.8% of which were biofilm producers. Of those, 69.2% were obtained from blood cultures. Isolates were obtained from several wards: 25% infectious diseases ward, 18% nephrology, 18% intensive care units, 14% geriatric ward, 7% plastic surgery, and 18% from other wards. The majority of the studied subjects were men (34.6%), and the mean age was 41 years. The majority of the isolates were susceptible to levofloxacin (94.1%) and to trimethoprim-sulfamethoxazole (76.4%) in planktonic assays. All the isolates were resistant to both antibiotics when analyzing biofilm cells. Levofloxacin resistance was at least four-fold higher in biofilm cells compared to planktonic cells. Trimethoprim-sulfamethoxazole resistance was at least ten-fold higher in biofilm cells compared to planktonic cells. Conclusion The majority of S. maltophilia clinical isolates causing blood infections in a hospital in Mexico were able to produce biofilm. The production of biofilm in S. maltophilia strains enhanced resistance to levofloxacin and trimethoprim-sulfamethoxazole. Disclosures All Authors: No reported disclosures

Previous studies have suggested a role of the endocannabinoid system in metabolic diseases, such as diabetes. We investigated the effect of diabetes on cannabinoid receptor type 1 (CB1) expression and cannabinoid-induced vasorelaxation in rat aorta rings. Aortas from healthy rats and from rats with experimentally induced diabetes were used to compare the vasorelaxant effect of the cannabinoid agonist arachidonylcyclopropylamide (ACPA) and CB1 expression and localization. After 4–8 weeks of diabetes induction, CB1 receptor expression and CB1 phosphorylation were higher in aortic rings, in association with greater vasorelaxation induced by the CB1 agonist ACPA compared to healthy rats. The vasorelaxant effect observed in healthy rats is similar throughout the study. Further studies are needed to elucidate the implications of CB1 receptor overexpression in diabetes and its influence on the progression of the cardiovascular complications of this metabolic disease.

Background: Many models for predicting dengue epidemics use incidence and short-term changes in climate variables, however, studies in real-life scenarios for correlations of seroprevalence (SP) with long-term climate variables and with integration of socio-economic factors are scarce. Our objective was to analyse the combined correlation between socio-economic and climate variables with the SP of dengue in Mexico. Methods: We performed a seroepidemiological ecological study on the Mexican Pacific coast. Dengue SP was estimated by the presence of immunoglobulin G antibodies in 1278 inhabitants. We implemented multiple correlations with socio-economic, climatic and topographic characteristics using logistic regression, generalized linear models and non-linear regressions. Results: Dengue SP was 58%. The age-adjusted correlation was positive with the male sex, while a negative correlation was seen with socio-economic status (SES) and scholl level (SL). The annual temperature showed a positive correlation, while the altitude was negative. It should be noted that these correlations showed a marked 'S' shape in the non-linear model, suggesting three clearly defined scenarios for dengue risk. Conclusion: Low SES and SL showed an unexpected paradoxical protective effect. Altitude above sea level and annual temperature are the main determinants for dengue in the long term. The identification of three clearly delineated scenarios for transmission could improve the accuracy of predictive models.

Introduction: Due to the coronavirus pandemic, identifying the infected individuals has become key to limiting its spread. Virus nucleic acid real-time RT-PCR testing has become the current standard diagnostic method but high demand could lead to shortages. Therefore, we propose a detection strategy using a one-step nested RT-PCR. Methodology: The nucleotide region in the ORF1ab gene that has the greatest differences between the human coronavirus and the bat coronavirus was selected. Primers were designed after that sequence. All diagnostic primers are species-specific since the 3´ end of the sequence differs from that of other species. A primer set also creates a synthetic positive control. Amplified products were seen in a 2.5% agarose gel, as well as in an SYBR Green-Based Real-Time RT-PCR. Results: Amplification was achieved for the positive control and specific regions in both techniques. Conclusions: This new technique is flexible and easy to implement. It does not require a real-time thermocycler and can be interpreted in agarose gels, as well as adapted to quantify the viral genome. It has the advantage that if the coronavirus mutates in one of the key amplification nucleotides, at least one pair can still amplify, thanks to the four diagnostic primers.

Chagas disease (ChD) is a parasitosis caused by the protozoan Trypanosoma cruzi (Tc). It is endemic to almost all Latin American countries, including the southern United States. The acute form of ChD and its actual incidence have rarely been described in Mexico, despite the extensive presence of favorable niches for its transmission. The objective of this study was to estimate the frequency of acute ChD in febrile patients at the central Pacific coast of Mexico. For this, we surveyed patients with persistent fever (5 to 10 days) in five hospitals at the Mexican states of Jalisco, Colima, and Nayarit in 2012. Samples were taken from a total of 485 patients to detect Tc in blood using the polymerase chain reaction (PCR) test and direct microscopic examination. Of these subjects, 10 were positive for PCR and none for microscopic examination (2% in 12 months). We adjusted this rate by the total people at risk in the area and obtained an incidence of 7.4/100,000 habs./year. The positive cases showed no association with sex, rural settlement, or pet ownership, only with the contact with Triatominae insects (odds ratio = 9.22 and confidence interval: 1.93-44.06). The clinical picture of positive patients showed an association with the diagnosis of lower respiratory tract infections. Meanwhile, only one fatal case showed the typical picture of acute fatal cardiomyopathy. The pulmonary manifestations of our patients suggest possible lung pathogenicity of Tc, which merits further investigation. Our findings differ markedly from the official reports for ChD. This difference suggests an underestimation of the disease. These findings urge the Mexican health authorities to implement more vigorous actions aimed at improving medical skills in the timely diagnosis of ChD, as well as to apply efficient preventive programs.

Objectives The purpose of this study is to analyse the effect of a community participation programme based on the ecosystem model on the incidence of dengue in urban communities.MethodsA randomized controlled field trial was conducted in the state of Colima, Mexico. The intervention consisted of a community participation programme focused on the ecosystem; simultaneously, the control groups were communities that only received the usual official prevention programs. The incidence of dengue was estimated in people of both groups due to the appearance of de novo IgM antibodies during the follow-up period.ResultsThe incidence of dengue in the intervened group was 2.58%/month (n = 818) and in control group 2.26%/month (n = 994), with a risk ratio of 1.14 (95% CI 0.89–1.45) and a PAF of 0.06 (95% CI − 0.056 to 0.16). The A. aegypti larval density (Breteau Index) was reduced in the treated group.Conclusions The implementation of a community participation programme in the cities of Colima, Mexico, showed a slightly counterproductive effect on the incidence of dengue. This happened even with a reduction in the A. aegypti index.

Background: Surveillance of antimicrobial resistance (AMR) requires an international approach with national and local strategies. Our aim was to summarize a retrospective 10-year report of antibiotic resistance of gram-positive and gram-negative bacteria in Mexico. Methods: A total of 46 centers from 22 states of Mexico participated. Databases of AMR from January 2009 to December 2018 were included for most species. The 10-year period was divided into five 2-year periods. Results: For Staphylococcus aureus, a decrease in resistance in all specimens was observed for erythromycin and oxacillin (p < 0.0001 for each). For Enterobacter spp., resistance to meropenem increased for urine specimens (p = 0.0042). For Klebsiella spp., increased drug resistance in specimens collected from blood was observed for trimethoprim/sulfamethoxazole, gentamicin, tobramycin (p < 0.0001 for each), meropenem (p = 0.0014), and aztreonam (p = 0.0030). For Acinetobacter baumannii complex, high drug resistance was detected for almost all antibiotics, including carbapenems, except for tobramycin, which showed decreased resistance for urine, respiratory, and blood isolates (p < 0.0001 for each), and for amikacin, which showed a decrease in resistance in urine specimens (p = 0.0002). An increase in resistance to cefepime was found for urine, respiratory, and blood specimens (p < 0.0001 for each). For Pseudomonas aeruginosa, aztreonam resistance increased for isolates recovered from blood (p = 0.0001). Conclusion: This laboratory-based surveillance of antibiotic resistance shows that resistance is increasing for some antibiotics in different bacterial species in Mexico and highlights the need for continuous monitoring of antibiotic resistance.

Introduction: Patients on dialysis have important changes in body composition. Objectives: To determine the correlation between skinfold thickness (SKF) and bioimpedance analysis (BIA) for estimating fat mass (FM) and lean body mass (LBM) in patients undergoing hemodialysis (HD) and peritoneal dialysis (PD). Methods: Cross-sectional study. We included 50 patients under dialysis treatment. To measure SKF, we used the Lange® skinfold caliper (Beta Technology, California, USA) and we carried out the impedance analysis with the Bodystat Quadscan 4000® (Quadscan, Isle of Man, UK). The measurements were performed post-hemodialysis. The PD patients were measured with and without peritoneal dialysate and body weight was corrected for peritoneal fluid. We determined the Pearson's correlation coefficient between SKF and BIA for estimating FM and LBM. We also evaluated the influence of age, sex, diuretic use, dialysis vintage, extracellular water (ECW), and intracellular water (ICW) through a multivariate regression analysis. Results: Of the 50-patient total, 29 were men (58%) and patient mean age was 46.3 ± 16.5 years. The correlation between SKF and BIA was r = 0.784 (p < 0.001) for FM and r = 0.925 (p < 0.001) for LBM. Age and sex influenced the variability of FM, whereas sex, age, and ECW influenced the variability of LBM, both evaluated through the SKF and BIA methods. Conclusion: SKF and BIA are useful methods in clinical practice. The strong and statistically significant correlations between the two methods show they are interchangeable. Age, sex, ECW, and ICW influence the variability of FM and LBM.