Presentación.

México cuenta con más de tres décadas de gran experiencia en la aplicación de Encuestas Nacionales de Salud. La primera Encuesta de Salud fue realizada por la Secretaría de Salud (SS) en el año de 1986; tan sólo dos años después se llevó a cabo la primera Encuesta Nacional de Nutrición, enfocada al área materno-infantil. Posteriormente, la Secretaría de Salud encargó al Instituto Nacional de Salud Pública (INSP) que realizara en 1999 una segunda Encuesta Nacional de Nutrición materno-infantil y, en el año 2000, una Encuesta Nacional de Salud. En 2006, bajo el esfuerzo del INSP y de la SS, se unen ambas encuestas, lo que da origen a la primera Encuesta Nacional de Salud y Nutrición (Ensanut), la cual incluye, en un mismo operativo, la evaluación de la nutrición y de la salud en toda la población a nivel nacional y estatal.

Metodología de la Encuesta Nacional de Salud y Nutrición 2021.

Objetivo. Describir el diseño de la Encuesta Nacional de Salud y Nutrición 2021 (Ensanut 2021). Material y métodos. La Ensanut 2021 es una encuesta probabilística de hogares que forma parte de la serie de Ensanut Continua 2020-2024. En esta ocasión se describen el alcance, el muestreo, la medición y la organización logística. Resultados. Se planea obtener al menos 12 060 entrevistas de hogar completas a nivel nacional y 9 837 muestras para determinar seropositividad a SARS-CoV-2 a nivel nacional. Conclusiones. La Ensanut 2021 permitirá realizar inferencias regionales sobre la prevalencia de seropositividad a SARS-CoV-2 y también acumular información para realizar inferencias estatales en el año 2024.

The hidden burden of Chikungunya in central Mexico: results of a small-scale serosurvey.

OBJECTIVE: To estimate the seroprevalence of CHKV antibodies and assess correlates of seropositivity at a small geographical scale. MATERIALS AND METHODS: A community-based serosurvey of 387 households in Puente de Ixtla, Morelos (central Mexico). Serum IgG antibodies to CHKV were detected by immunoassay. RESULTS: From 27 April to 29 May 2016, we interviewed and collected blood samples from 387 individuals at the same number of households. A total of 114 (29.5%) participants were seropositive to CHK, 36 (31.6%) of them reported no symptoms of CHKV infection within 12 months before the survey. CONCLUSIONS: The estimated seroprevalence to CHKV antibodies was higher than expected by the small number of confirmed cases of CHKV infection reported in Mexico by the National Surveillance System.

Salmonella downregulates Nod-like receptor family CARD domain containing protein 4 expression to promote its survival in B cells by preventing inflammasome activation and cell death.

Salmonella infects and survives within B cells, but the mechanism used by the bacterium to promote its survival in these cells is unknown. In macrophages, flagellin secreted by Salmonella activates the Nod-like receptor (NLR) family CARD domain containing protein 4 (NLRC4) inflammasome, leading to the production of IL-1ß and pyroptosis of infected cells. In this study, we demonstrated that the NLRC4 inflammasome is functional in B cells; however, in Salmonella-infected B cells, IL-1ß secretion is prevented through the downregulation of NLRC4 expression. A functional Salmonella pathogenicity island 1 type III secretion system appears to be required for this process. Furthermore, infection induces Yap phosphorylation and promotes the interaction of Yap with Hck, thus preventing the transcriptional activation of NLRC4. The ability of Salmonella to inhibit IL-1ß production also prevents B cell death; thus, B cells represent an ideal niche in which Salmonella resides, thereby promoting its persistence and dissemination.

Risk factors for extended-spectrum ß-lactamases-producing Escherichia coli urinary tract infections in a tertiary hospital.

OBJECTIVE: To assess the risks factors for urinary tract infections (UTIs) caused by Extended-Spectrum Beta-Lactamases (ESBLs)-producing E. coli and the molecular characterization of ESBLs. MATERIALS AND METHODS: A case-control study was performed to identify risk factors in consecutively recruited patients with UTIs caused by ESBLs or non-ESBLs-producing E. coli in a tertiary hospital in Mexico. RESULTS: ESBLs-producing E. coli were isolated from 22/70 (31%) patients with E. coli UTIs over a three month period. All isolates were resistant to cephalosporins and quinolones but susceptible to carbapenems, amikacin and nitrofurantoin. Prior antibiotic treatment with more than two antibiotic families (OR=6.86; 95%CI 1.06-157.70; p=0.028), recurrent symptomatic UTIs (OR=5.60; 95%CI 1.88-17.87; p=0.001) and previous hospitalization (OR=5.06; 95%CI 1.64-17.69; p=0.002) were significant risk factors. Sixteen isolates harbored the beta-lactamase (bla)CTX-M-15 gene and five the blaTEM-1 gene. CONCLUSIONS: One of every three patients presented UTIs with ESBLs-producing beta-lactams and fluoroquinolone resistant E. coli. Risk factors and resistance patterns must be taken into account for developing antibiotic use policies in these settings.

Presence and Persistence of ESKAPEE Bacteria before and after Hospital Wastewater Treatment.

The metagenomic surveillance of antimicrobial resistance in wastewater has been suggested as a methodological tool to characterize the distribution, status, and trends of antibiotic-resistant bacteria. In this study, a cross-sectional collection of samples of hospital-associated raw and treated wastewater were obtained from February to March 2020. Shotgun metagenomic sequencing and bioinformatic analysis were performed to characterize bacterial abundance and antimicrobial resistance gene analysis. The main bacterial phyla found in all the samples were as follows: Proteobacteria, Bacteroides, Firmicutes, and Actinobacteria. At the species level, ESKAPEE bacteria such as E. coli relative abundance decreased between raw and treated wastewater, but S. aureus, A. baumannii, and P. aeruginosa increased, as did the persistence of K. pneumoniae in both raw and treated wastewater. A total of 172 different ARGs were detected; blaOXA, blaVEB, blaKPC, blaGES, mphE, mef, erm, msrE, AAC(6'), ant(3″), aadS, lnu, PBP-2, dfrA, vanA-G, tet, and sul were found at the highest abundance and persistence. This study demonstrates the ability of ESKAPEE bacteria to survive tertiary treatment processes of hospital wastewater, as well as the persistence of clinically important antimicrobial resistance genes that are spreading in the environment.

Multidrug-Resistant Staphylococcus sp. and Enterococcus sp. in Municipal and Hospital Wastewater: A Longitudinal Study.

The objective of the study was to detect multidrug-resistant Staphylococcus sp. and Enterococcus sp. isolates in municipal and hospital wastewater and to determine their elimination or persistence after wastewater treatment. Between August 2021 and September 2022, raw and treated wastewater samples were collected at two hospital and two community wastewater treatment plants (WWTPs). In each season of the year, two treated and two raw wastewater samples were collected in duplicate at each of the WWTPs studied. Screening and presumptive identification of staphylococci and enterococci was performed using chromoagars, and identification was performed with the Matrix Assisted Laser Desorption Ionization Time of Flight mass spectrometry (MALDI-TOF MS®). Antimicrobial susceptibility was performed using VITEK 2® automated system. There were 56 wastewater samples obtained during the study period. A total of 182 Staphylococcus sp. and 248 Enterococcus sp. were identified. The highest frequency of Staphylococcus sp. isolation was in spring and summer (n = 129, 70.8%), and for Enterococcus sp. it was in autumn and winter (n = 143, 57.7%). Sixteen isolates of Staphylococcus sp. and sixty-three of Enterococcus sp. persisted during WWTP treatments. Thirteen species of staphylococci and seven species of enterococci were identified. Thirty-one isolates of Staphylococcus sp. and ninety-four of Enterococcus sp. were multidrug-resistant. Resistance to vancomycin (1.1%), linezolid (2.7%), and daptomycin (8.2%/10.9%%), and a lower susceptibility to tigecycline (2.7%), was observed. This study evidences the presence of Staphylococcus sp. and Enterococcus sp. resistant to antibiotics of last choice of clinical treatment, in community and hospital wastewater and their ability to survive WWTP treatment systems.

Salmonella infects B cells by macropinocytosis and formation of spacious phagosomes but does not induce pyroptosis in favor of its survival.

We have previously reported that Salmonella infects B cells and survives within endosomal-lysosomal compartments. However, the mechanisms used by Salmonella to enter B cells remain unknown. In this study, we have shown that Salmonella induces its own entry by the induction of localized ruffling, macropinocytosis, and spacious phagosome formation. These events were associated with the rearrangement of actin and microtubule networks. The Salmonella pathogenesis island 1 (SPI-1) was necessary to invade B cells. In contrast to macrophages, B cells were highly resistant to cell death induced by Salmonella. These data demonstrate the ability of Salmonella to infect these non-professional phagocytic cells, where the bacterium can find an ideal intracellular niche to support persistence and the possible dissemination of infection.

Antimicrobial resistance: One Health approach.

In this research, a review of antimicrobial resistance (AMR) is conducted as part of the One Health approach. A review of publications, which included "antimicrobial resistance" and "One Health," was conducted. Among the global health problems, AMR is the one that most clearly illustrates the One Health approach. AMR is a critical global problem affecting humans, the environment, and animals. This is related to each of these three components due to the irresponsible and excessive use of antimicrobials in various sectors (agriculture, livestock, and human medicine). Improper management of antimicrobials, inadequate control of infections, agricultural debris, pollutants in the environment, and migration of people and animals infected with resistant bacteria facilitate the spread of resistance. The study aimed to analyze the problem of AMR from a health perspective to analyze the different actors involved in One Health.

Antimicrobial Resistance Patterns and Clonal Distribution of E. coli, Enterobacter spp. and Acinetobacter spp. Strains Isolated from Two Hospital Wastewater Plants.

The objective of this study was to determine the presence and persistence of antimicrobial-resistant enterobacteria and their clonal distribution in hospital wastewater. A descriptive cross-sectional study was carried out in wastewater from two Mexico City tertiary level hospitals. In February and March of 2020, eight wastewater samples were collected and 26 isolates of enterobacteria were recovered, 19 (73.1%) isolates were identified as E. coli, 5 (19.2%) as Acinetobacter spp. and 2 (7.7%) as Enterobacter spp. Antimicrobial susceptibility profiles were performed using the VITEK 2® automated system and bacterial identification was performed by the Matrix-Assisted Laser Desorption/Ionization-Time of Flight mass spectrometry (MALDI-TOF MS®). ESBL genes were detected by polymerase chain reaction (PCR) and clonal distributions of isolates were determined by pulsed-field gel electrophoresis (PFGE). E. coli susceptibility to different classes of antimicrobials was analyzed and resistance was mainly detected as ESBLs and fluoroquinolones. One E. coli strain was resistant to doripenem, ertapenem, imipenem and meropenem. The analysis by PCR showed the presence of specific ß-lactamases resistance genes (blaKPC, blaCTX-M). The PFGE separated the E. coli isolates into 19 different patterns (A-R). PFGE results of Acinetobacter spp. showed the presence of a majority clone A. Surveillance of antimicrobial resistance through hospital wastewater is an important tool for early detection of clonal clusters of clinically important bacteria with potential for dissemination.

Surveillance of Antimicrobial Resistance in Hospital Wastewater: Identification of Carbapenemase-Producing Klebsiella spp.

The objective of this study was to investigate the presence and persistence of carbapenemase-producing Klebsiella spp. isolated from wastewater and treated wastewater from two tertiary hospitals in Mexico. We conducted a descriptive cross-sectional study in two hospital wastewater treatment plants, which were sampled in February 2020. We obtained 30 Klebsiella spp. isolates. Bacterial identification was carried out by the Matrix-Assisted Laser Desorption/Ionization-Time of Flight mass spectrometry (MALDI-TOF MS®) and antimicrobial susceptibility profiles were performed using the VITEK2® automated system. The presence of carbapenem resistance genes (CRGs) in Klebsiella spp. isolates was confirmed by PCR. Molecular typing was determined by pulsed-field gel electrophoresis (PFGE). High rates of Klebsiella spp. resistance to cephalosporins and carbapenems (80%) were observed in isolates from treated wastewater from both hospitals. The molecular screening by PCR showed the presence of blaKPC and blaOXA-48-like genes. The PFGE pattern separated the Klebsiella isolates into 19 patterns (A-R) with three subtypes (C1, D1, and I1). Microbiological surveillance and identification of resistance genes of clinically important pathogens in hospital wastewater can be a general screening method for early determination of under-detected antimicrobial resistance profiles in hospitals and early warning of outbreaks and difficult-to-treat infections.

Diagnosis of bacterial meningitis caused by Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae using a multiplex real-time PCR technique.

Bacterial meningitis is one of the diseases that, despite the introduction of several vaccines, remains a serious public health concern. Streptococcus pneumoniae (Spn), Neisseria meningitidis (Nm), and Haemophilus influenzae (Hi) are responsible for most cases diagnosed in children, adolescents, and adult population. Rapid, sensitive, and specific laboratory assays are critical for effective diagnosis and treatment, particularly in countries like Mexico in which culture positivity rates are very low due to the use of antibiotics prior to sample collection and to delay in transporting samples to the laboratory. The aim of this study was to evaluate the use of real-time polymerase chain reaction (RT-PCR) of cerebrospinal fluid (CSF) as a rapid diagnostic test for bacterial meningitis and compare these results with bacterial culture in three general hospitals in Mexico. During a 5-year period (2014-2018), a total of 512 CSF samples obtained from patients in whom infectious meningitis was suspected as initial clinical diagnosis were tested with RT-PCR with species-specific targets for the three pathogens. For Spn, 5.07% samples were RT-PCR positive; 0.39% for Nm and none for Hi. Only five RT-PCR Spn positive samples had a positive culture. Sensitivity and specificity estimates for RT-PCR are 100% and 95.46%, respectively. DNA amplification methods can provide better sensitive diagnostic tests than the reference standard, which is culture, particularly when antimicrobial treatment is initiated before clinical samples can be obtained.

The hidden burden of Chikungunya in central Mexico: results of a small-scale serosurvey / La carga oculta de Chikungunya en el centro de México: resultados de una encuesta serológica a pequeña escala

Abstract: Objective: To estimate the seroprevalence of CHKV antibodies and assess correlates of seropositivity at a small geographical scale. Materials and methods: A community-based serosurvey of 387 households in Puente de Ixtla, Morelos (central Mexico). Serum IgG antibodies to CHKV were detected by immunoassay. Results: From 27 April to 29 May 2016, we interviewed and collected blood samples from 387 individuals at the same number of households. A total of 114 (29.5%) participants were seropositive to CHK, 36 (31.6%) of them reported no symptoms of CHKV infection within 12 months before the survey. Conclusion: The estimated seroprevalence to CHKV antibodies was higher than expected by the small number of confirmed cases of CHKV infection reported in Mexico by the National Surveillance System.

Resumen: Objetivo: Estimar la seroprevalencia de anticuerpos CHKV y evaluar correlatos de seropositividad a pequeña escala geográfica. Material y métodos: Encuesta serológica comunitaria en 387 hogares en Puente de Ixtla, Morelos (región central de México). Se detectaron anticuerpos IgG contra CHKV mediante inmunoensayo. Resultados: Del 27 de abril al 29 de mayo de 2016 se entrevistó a 387 individuos en el mismo número de hogares y se recolectaron muestras de sangre de los mismos. En total, 114 (29.5%) participantes fueron seropositivos a CHK, 36 (31.6%) de ellos negaron síntomas de infección por CHKV durante los 12 meses previos a la encuesta. Conclusión: La seroprevalencia estimada de anticuerpos contra CHKV; fue mayor a la esperada con base en el pequeño número de casos confirmados de infección por CHKV informados en México por el Sistema Nacional de Vigilancia.

Risk factors for extended-spectrum ß-lactamases-producing Escherichia coli urinary tract infections in a tertiary hospital / Factores de riesgo en infecciones de vías urinarias causadas por Escherichia coli productora de ß-lactamasas de espectro extendido en un hospital de tercer nivel

Objective. To assess the risks factors for urinary tract infections (UTIs) caused by Extended-Spectrum Beta-Lactamases (ESBLs)-producing E. coli and the molecular characterization of ESBLs. Materials and methods. A case-control study was performed to identify risk factors in consecutively recruited patients with UTIs caused by ESBLs or non-ESBLs-producing E. coli in a tertiary hospital in Mexico. Results. ESBLs-producing E. coli were isolated from 22/70 (31%) patients with E. coli UTIs over a three month period. All isolates were resistant to cephalosporins and quinolones but susceptible to carbapenems, amikacin and nitrofurantoin. Prior antibiotic treatment with more than two antibiotic families (OR=6.86; 95%CI 1.06-157.70; p=0.028), recurrent symptomatic UTIs (OR=5.60; 95%CI 1.88-17.87; p=0.001) and previous hospitalization (OR=5.06; 95%CI 1.64-17.69; p=0.002) were significant risk factors. Sixteen isolates harbored the beta-lactamase (bla)CTX-M-15 gene and five the blaTEM-1 gene. Conclusions. One of every three patients presented UTIs with ESBLs-producing beta-lactams and fluoroquinolone resistant E. coli. Risk factors and resistance patterns must be taken into account for developing antibiotic use policies in these settings.

Objetivo. Evaluar los factores de riesgo en infecciones de vías urinarias (IVUs) causadas por E. coli productora de Beta-Lactamasas de espectro extendido (BLEEs) y caracterizar las BLEEs. Material y métodos. Estudio de casos y controles en pacientes consecutivos con IVUs causadas por E. coli productoras o no de BLEEs en un hospital de referencia. Resultados. E. coli productora de BLEEs se aisló en 22/70 (31%) pacientes con IVUs por E. coli durante un periodo de tres meses. Todos los aislamientos fueron resistentes a cefalosporinas y quinolonas, pero susceptibles a carbapenemes, amikacina y nitrofurantoina. Factores de riesgo significativos incluyeron tratamiento previo con más de dos familias de antibióticos (OR=6.86; IC95% 1.06-157.70; p=0.028), IVUs sintomáticas recurrentes (OR=5.60; IC95% 1.88-17.87; p=0.001) y hospitalizaciones previas (OR=5.06; IC95% 1.64-17.69; p=0.002). Dieciséis aislamientos presentaron el gen betalactamasas (bla)CTX-M-15 y cinco el gen blaTEM-1. Conclusiones. Uno de cada tres pacientes presentó IVU con E. coli resistente a beta-lactámicos, fluoroquinolonas y productora de BLEEs. En estos casos, los factores de riesgo y patrones de resistencia deberían tomarse en cuenta para recomendar tratamiento.