Characterization and efficacy of Salmonella phage cocktail PHA46 in the control of Salmonella Newport and Typhimurium internalized into cherry tomatoes.

Non-typhoid Salmonella enterica causes salmonellosis illness, and this bacterium can contaminate food throughout the production chain, including those that are consumed as raw products. Salmonella enterica can adhere to and internalize into fresh produce such as cherry tomatoes. It has been reported that lytic bacteriophages (phages) can be used as a biocontrol agent in the agricultural field, being an alternative for the control of Salmonella in red meat, fish, lettuce, and cabbage. The aim of this study was to characterize the two phages present in the PHA46 cocktail to determine their morphology, genome, host range, and resistance to different temperatures and pHs values; and later evaluate their lytic activity to reduce the adherence to and internalization of Salmonella enterica serovars Newport and Typhimurium into cherry tomatoes. In addition, in this work, we also explored the effect of the PHA46 cocktail on the virulence of S. Newport-45 and S. Typhimurium SL1344, recovered from the interior of cherry tomatoes, on the lifespan of the animal model Caenorhabditis elegans. The nematode C. elegans, recently has been used to test the virulence of Salmonella and it is easy to maintain and work with in the laboratory. The results revealed that the morphology obtained by Transmission Electron Microscopy of two phages from the PHA46 cocktail correspond to a myovirus, the analyses of their genomes sequences did not report virulence or antimicrobial resistance genes. The PHA46 sample is specific for 33 different serovars from different Salmonella strains and shows stability at 7 °C and pH 6. Also, the PHA46 cocktail was effective in reducing the adherence of S. Newport-45 and S. Typhimurium SL1344 to cherry tomatoes, at an average of 0.9 log10, respectively. Regarding internalized bacteria, the reduction was at an average of 1.2 log10, of the serovars mentioned above. The lifespan experiments in C. elegans showed by itself, that the PHA46 cocktail was harmless to the nematode, and the virulence from both Salmonella strains grown in vitro is diminished in the presence of the PHA46 cocktail. In conclusion, these results showed that the PHA46 cocktail could be a good candidate to be used as a biocontrol agent against Salmonella enterica.

Tracing the History of Hepatitis E Virus Infection in Mexico: From the Enigmatic Genotype 2 to the Current Disease Situation.

Hepatitis E virus (HEV) is the major cause of acute viral hepatitis worldwide. This virus is responsible for waterborne outbreaks in low-income countries and zoonosis transmission in industrialized regions. Initially, considered self-limiting, HEV may also lead to chronic disease, and evidence supports that infection can be considered a systemic disease. In the late 1980s, Mexico became a hot spot in the study of HEV due to one of the first virus outbreaks in Latin America related to enterically transmitted viral non-A, non-B hepatitis. Viral stool particles recovered from Mexican viral hepatitis outbreaks represented the first identification of HEV genotype (Gt) 2 (Gt2) in the world. No new findings of HEV-Gt2 have been reported in the country, whereas this genotype has been found in countries on the African continent. Recent investigations in Mexico have identified other strains (HEV-Gt1 and -Gt3) and a high frequency of anti-HEV antibodies in animal and human populations. Herein, the potential reasons for the disappearance of HEV-Gt2 in Mexico and the advances in the study of HEV in the country are discussed along with challenges in studying this neglected pathogen. These pieces of information are expected to contribute to disease control in the entire Latin American region.

Prevalence of symptoms, comorbidities, and reinfections in individuals infected with Wild-Type SARS-CoV-2, Delta, or Omicron variants: a comparative study in western Mexico.

Introduction: The variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been classified into variants of interest (VOIs) or concern (VOCs) to prioritize global monitoring and research on variants with potential risks to public health. The SARS-CoV-2 high-rate mutation can directly impact the clinical disease progression, epidemiological behavior, immune evasion, vaccine efficacy, and transmission rates. Therefore, epidemiological surveillance is crucial for controlling the COVID-19 pandemic. In the present study, we aimed to describe the prevalence of wild-type (WT) SARS-CoV-2 and Delta and Omicron variants in Jalisco State, Mexico, from 2021 to 2022, and evaluate the possible association of these variants with clinical manifestations of COVID-19. Methods: Four thousand and ninety-eight patients diagnosed with COVID-19 by real-time PCR (COVIFLU, Genes2Life, Mexico) from nasopharyngeal samples from January 2021 to January 2022 were included. Variant identification was performed by the RT-qPCR Master Mut Kit (Genes2Life, Mexico). A study population follow-up was performed to identify patients who had experienced reinfection after being vaccinated. Results and Discussion: Samples were grouped into variants according to the identified mutations: 46.3% were Omicron, 27.9% were Delta, and 25.8% were WT. The proportions of dry cough, fatigue, headache, muscle pain, conjunctivitis, fast breathing, diarrhea, anosmia, and dysgeusia were significantly different among the abovementioned groups (p < 0.001). Anosmia and dysgeusia were mainly found in WT-infected patients, while rhinorrhea and sore throat were more prevalent in patients infected with the Omicron variant. For the reinfection follow-up, 836 patients answered, from which 85 cases of reinfection were identified (9.6%); Omicron was the VOC that caused all reported reinfection cases. In this study, we demonstrate that the Omicron variant caused the biggest outbreak in Jalisco during the pandemic from late December 2021 to mid-February 2022 but with a less severe form than the one demonstrated by Delta and WT. The co-analysis of mutations and clinical outcomes is a public health strategy with the potential to infer mutations or variants that could increase disease severity and even be an indicator of long-term sequelae of COVID-19.

Beyond SARS-CoV-2: epidemiological surveillance of respiratory viruses in Jalisco, Mexico.

Introduction: Respiratory viral infections represent a significant global health burden. Historically, influenza, rhinovirus, respiratory syncytial virus, and adenovirus have been the prevalent viruses; however, the landscape shifted with the widespread emergence of SARS-CoV-2. The aim of this study is to present a comprehensive epidemiological analysis of viral respiratory infections in Jalisco, Mexico. Methods: Data encompassing individuals with flu-like symptoms from July 2021 to February 2023 was scrutinized for viral diagnosis through PCR multiplex. The effect of social mobility on the increase in respiratory viral diagnosis infection was considered to estimate its impact. Additionally, sequences of respiratory viruses stored in public databases were retrieved to ascertain the phylogenetic classification of previously reported viruses in Mexico. Results: SARS-CoV-2 was the most detected virus (n = 5,703; 92.2%), followed by influenza (n = 479; 7.78%). These viruses were also found as the most common co-infection (n = 11; 50%), and for those with influenza, a higher incidence of severe disease was reported (n = 122; 90.4%; p < 0.001). Regarding comorbidities and unhealthy habits, smoking was found to be a risk factor for influenza infection but a protective factor for SARS-CoV-2 (OR = 2.62; IC 95%: 1.66-4.13; OR = 0.65; IC 95%: 0.45-0.94), respectively. Furthermore, our findings revealed a direct correlation between mobility and the prevalence of influenza infection (0.214; p < 0.001). Discussion: The study presents evidence of respiratory virus reemergence and prevalence during the social reactivation, facilitating future preventive measures.

Specific T-Cell Immune Response to SARS-CoV-2 Spike Protein over Time in Naïve and SARS-CoV-2 Previously Infected Subjects Vaccinated with BTN162b2.

Due to the COVID-19 pandemic, the rapid development of vaccines against SARS-CoV-2 has been promoted. BNT162b2 is a lipid-nanoparticle mRNA vaccine with 95% efficacy and is the most administered vaccine globally. Nevertheless, little is known about the cellular immune response triggered by vaccination and the immune behavior over time. Therefore, we evaluated the T-cell immune response against the SARS-CoV-2 spike protein and neutralization antibodies (nAbs) in naïve and SARS-CoV-2 previously infected subjects vaccinated with BTN162b2. Methods: Forty-six BTN162b2 vaccinated subjects were included (twenty-six naïve and twenty SARS-CoV-2 previously infected subjects vaccinated with BTN162b2). Blood samples were obtained at basal (before vaccination), 15 days after the first dose, and 15 days after the second dose, to evaluate cellular immune response upon PBMC's stimulation and cytokine levels. The nAbs were determined one and six months after the second dose. Results: SARS-CoV-2 previously infected subjects vaccinated with BTN162b2 showed the highest proportion of nAbs compared to naïve individuals one month after the second dose. However, women were more prone to lose nAbs percentages over time significantly. Furthermore, a diminished CD154+ IFN-γ+ CD4+ T-cell response was observed after the second BTN162b2 dose in those with previous SARS-CoV-2 infection. In contrast, naïve participants showed an overall increased CD8+ IFN-γ+ TNF-α+ T-cell response to the peptide stimulus. Moreover, a significant reduction in IP-10, IFN-λI, and IL-10 cytokine levels was found in both studied groups. Additionally, the median fluorescence intensity (MFI) levels of IL-6, IFNλ-2/3, IFN-𝛽, and GM-CSF (p < 0.05) were significantly reduced over time in the naïve participants. Conclusion: We demonstrate that a previous SARS-CoV-2 infection can also impact cellular T-cell response, nAbs production, and serum cytokine concentration. Therefore, the study of T-cell immune response is essential for vaccination scheme recommendations; future vaccine boost should be carefully addressed as continued stimulation by vaccination might impact the T-cell response.

Cell Culture Isolation and Whole Genome Characterization of Hepatitis E Virus Strains from Wild Boars in Germany.

Infection with hepatitis E virus (HEV) can cause acute and chronic hepatitis in humans. The HEV genotype 3 can be zoonotically transmitted from animals to humans, with wild boars representing an important reservoir species. Cell culture isolation of HEV is generally difficult and mainly described for human isolates so far. Here, five sera and five liver samples from HEV-RNA-positive wild boar samples were inoculated onto PLC/PRF/5 cells, incubated for 3 months and thereafter passaged for additional 6 weeks. As demonstrated by RT-qPCR, immunofluorescence and immune electron microscopy, virus was successfully isolated from two liver samples, which originally contained high HEV genome copy numbers. Both isolates showed slower growth than the culture-adapted HEV strain 47832c. In contrast to this strain, the isolated strains had no insertions in their hypervariable genome region. Next generation sequencing using an HEV sequence-enriched library enabled full genome sequencing. Strain Wb108/17 belongs to subtype 3f and strain Wb257/17 to a tentative novel subtype recently described in Italian wild boars. The results indicate that HEV can be successfully isolated in cell culture from wild boar samples containing high HEV genome copy numbers. The isolates may be used further to study the zoonotic potential of wild boar-derived HEV subtypes.

A Comprehensive Descriptive Epidemiological and Clinical Analysis of SARS-CoV-2 in West-Mexico during COVID-19 Pandemic 2020.

This study aimed to summarize the epidemiological and clinical characteristics of COVID-19 from Western Mexico people during 2020. A retrospective analysis from an electronic database of people visiting a sentinel center for molecular SARS-CoV-2 confirmatory diagnosis by RT-PCR from April to December 2020 was carried out for epidemiological and clinical description of COVID-19. Out of 23,211 patients evaluated, 6918 (29.8%) were confirmed for SARS-CoV-2 infection (mean age 38.5 ± 13.99), mostly females (53.8%). Comorbidities, such as diabetes (34.7%), obesity (31.15%), and hypertension (31.8%), presented an increased odds OR = 1.27, CI = 1.14-1.41; OR = 1.08, CI = 1.01-1.16; and OR = 1.09, CI = 0.99-1.19, respectively, for viral-infection. Moreover, fever, headache, and dry cough were the most frequent symptoms. No infection difference among sex was found. Those patients >60 years old were prone to COVID-19 severity (OR = 3.59, CI = 2.10-6.14), evaluated by the number of manifested symptoms, increasing with age. In conclusion, a high SARS-CoV-2 prevalence was found in Western Mexico. Comorbidities were frequent in infected people; nevertheless, no association with disease outcomes was observed, in contrast with the highest disease severity risk found in older patients; however, continuous monitoring should be carried since comorbidities have been reported as aggravating factors. This study can help the health officials for the elaboration of planning efforts of the disease management and others in the future.

Spatial and Temporal Distribution of Hepatitis A Virus and Hepatitis E Virus Among Children with Acute Hepatitis in Mexico.

Hepatitis A virus (HAV) and hepatitis E virus (HEV) cause most of the global burden of viral hepatitis. Geographical and seasonal patterns contribute to the epidemiological status of infectious diseases. The extent of these features in the setting of HAV and HEV infections has not been analyzed in detail. This point is important in highly endemic countries of both viruses, where the pediatric population is at high risk of contracting these infections. A comparison between the frequency of antibodies to HAV and HEV and viral RNA detection in serum samples from pediatric patients with acute hepatitis from South and West Mexico was performed. All samples were positive for HAV mono-infection, which was most frequently detected in the metropolitan areas during the rainy season in the South (90%) and all year round in the West (42%). No HEV mono-infection was detected in the studied regions. A 58% frequency for HAV/HEV co-infection was found in the West, predominantly in the metropolitan areas during the rainy months. A 10% frequency for co-infection broadly distributed in the South throughout the year was also found. Our findings underscore that the distribution of HAV and HEV infections varies through the year and differs among Mexico's distinct geographical regions.

Performance evaluation of a lateral flow assay for nasopharyngeal antigen detection for SARS-CoV-2 diagnosis.

BACKGROUND: SARS-CoV-2 has become a global pandemic due to its capacity for rapid transmission. In this context, an early and rapid diagnosis of infected patients that do not require expensive equipment or highly trained personnel is crucial in order to reduce the contagious rate. The aim of this study was to evaluate a chromatographic immunoassay's performance for the rapid diagnosis of SARS-CoV-antigen. METHODS: A cross-sectional study included 369 adults from Western México with diagnosis or suspicion of SARS-CoV-2 infection. Two samples were collected; a naso-oropharyngeal was used for a molecular determination of SARS-CoV-2 RNA. The molecular analysis was carried out using DeCoV19 Kit Triplex (Genes2life S.A.P.I.) based on the CDC diagnostic panel for N1, N2, and N3 regions. The second sample was retrieved from a nasopharyngeal rub and used for the rapid diagnosis of SARS-CoV-2 antigen employing the commercial STANDARD™ Q COVID-19 Ag Test (SD BIOSENSOR). RESULTS: Overall, in 28.2% of the patients was detected the SARS-CoV-2 RNA, and 21.4% were positive for antigen detection. The rapid antigen test showed a sensitivity and specificity of 75.9% and 100%, respectively, with a positive predictive and negative values of 100% and 91%. Symptoms as anosmia presented a high OR for the positive diagnosis for both test, reverse transcription-polymerase chain reaction (RT-PCR), and the rapid antigen test of 8.86 (CI = 4.91-16) and 6.09 (CI = 3.42-10.85), respectively. CONCLUSION: SD BIOSENSOR is a useful assay, but some caveats must be considered before the general implementation.

Evidence for Increased Inflammatory Cytokine Profile in Hepatitis E Virus-Infected Obese Patients: Implications for Chronic Liver Disease.

We aimed to characterize the contribution of hepatitis E virus (HEV) in perpetuating the cytokine-mediated inflammatory setting related to liver damage in the context of obesity. Herein, serum samples from patients with liver disease were retrospectively analyzed and categorized as normal-weight patients (NW), overweight patients (OW), obese patients (ObP), and high alcohol consumer patients (HAC), and biochemical, anthropometrical, and transient elastography measurements were obtained. The positivity for immunoglobulin M (IgM) and immunoglobulin G (IgG) anti-HEV antibodies in samples was determined by enzyme-linked immunosorbent assay. Available samples from ObP were tested by reverse transcription-nested polymerase chain reaction for the presence of HEV-RNA. Cytokine profile in the serum of ObP was identified using a multiplexed immune assay. Globally, the highest frequency of IgG anti-HEV was found in ObP (57.5%), followed by HAC (20%), OW (15%), and NW (7.5%). A strong association between HEV serology and obesity was found (odds ratio = 4.21, confidence interval = 1.91.9.27) with a cutoff of 29.3 kg/m2 (area under curve [AUC] = 0-66; p = 0.003) and, a 23.7% of available samples of ObP provided amplification of HEV genome. Cytokine analysis revealed significantly higher levels of proinflammatory cytokines (interleukin [IL]-12, interferon [IFN]-γ, and IL-1ß) in IgG anti-HEV-positive ObP than in IgG anti-HEV-negative ObP. Moreover, a high proportion of patients with positive serology showed advanced liver damage. In conclusion, the high percentage of anti-HEV antibodies and viral RNA detection in the setting of an excess of fat, along with an associated proinflammatory cytokine profile found in IgG anti-HEV-positive ObP with more severe liver disease, support an interplay between HEV and obesity.

First detection of hepatitis E virus genotype 3 as a common infectious agent in patients with chronic liver damage in Mexico.

INTRODUCTION AND OBJECTIVES: To characterize the virological features of hepatitis E virus (HEV) in serum from patients exhibiting chronic liver damage. METHODS: A data-base of 513 unrelated individuals from West-Mexico with liver-disease determined by clinical and biochemical tests and transient elastography between 2011 and 2016 were retrospectively analyzed. According to infectious etiologies, patients were classified as hepatitis B virus (HBV)-, hepatitis C virus (HCV)-infected patients, and patients exhibiting chronic liver damage with non-identified infectious etiological agent (NIIEA). Available serum samples from NIIEA-patients were tested by RT-nPCR for the presence of HEV-RNA and partially sequenced for genotyping. RESULTS: Out of the 513 cases, 5.85% were patients infected with HBV, 67.64% with HCV, and 26.51% were NIIEA-patients. Among 76 available samples from NIIEA-cases, 30.26% tested positive for HEV-RNA. Twelve (15.79%) partial HEV sequences allowed phylogenetic analysis, revealing the classification of HEV as HEV-Gt3. Advanced fibrosis (F3-F4 stage) was found in a 26.1% of patients with HEV-active infection. CONCLUSION: Although HCV is the main infectious agent related to chronic liver disease in Mexico, liver damage without an infectious etiology is common. Our findings reveal that an elevated rate of chronic liver disease might be represented by autochthonous infection of HEV-Gt3, whose detection makes Mexico unique in Latin-America with the circulation of HEV strains belonging to three genotypes (Gt1, Gt2, and Gt3). Thus, HEV infection should be a matter of health concern, and mandates for HEV screening to properly handle this commonly undiagnosed disease.

Challenges in Management of Hepatitis A Virus Epidemiological Transition in Mexico.

Hepatitis A virus (HAV) is the most common cause of acute viral hepatitis worldwide. The virus is mainly transmitted via the fecaloral route and, the incidence of infection is closely related to low socioeconomic conditions and poor sanitation. Mexico, previously categorized an area of high endemicity for HAV infection, is undergoing epidemiological transition. However, a limited number of HAV-related scientific reports regarding to virus burden is available. According to the local government health agency (Secretarla de Salud, SSA in Spanish), from 1994 to 2017 a reduction in the incidence of hepatitis related to HAV has been reported. However, HAV is still the most common cause of viral hepatitis in the country, and the pediatric population is the most prone to be infected with this virus. The analysis of the SSA data reveals that most of the reported cases from 1994 to 2017 were found in highly industrialized states. This information contradicts the documented relationship between the highest prevalence of infection and the lowest socio-economic status, and supports the necessity of viral detection and notification of HAV cases. Moreover, in spite that four HAV vaccines are available in Mexico and universal vaccination has been shown to be beneficial in developing countries in terms of declining endemicity, HAV vaccination is not mandatory in Mexico. In this review, preventive strategies including appropriate diagnosis, vaccination and public health policies on the basis of the epidemiologic status of HAV in Mexico are discussed.

Hepatitis E Virus Genotype 1 and Hepatitis A Virus Dual Infection in Pediatric Patients with a Low Socioeconomic Status from Mexico.

OBJECTIVE: We aimed to detect and characterize hepatitis E virus (HEV) RNA in sera samples from a pediatric population infected with the hepatitis A virus (HAV) exhibiting acute hepatitis and to correlate the infection status with the clinical outcome. METHODS: Seventy-five ELISA-positive samples from children containing anti-HAV and anti-HEV IgM were used to amplify and characterize partial regions within HEV ORF2. A statistical comparison of clinical data between HEV IgM-positive/HEV RNA-positive patients and HEV IgM-positive/HEV RNA-negative patients was performed. RESULTS: Thirteen out of 75 IgM-positive samples provided amplification of discrete regions of the HEV genome. Nested RT-PCR-based detection and subsequent sequencing of 5 samples confirmed the identity of HEV genotype 1 (G1), which had not been previously reported in Mexico. Though not significant, a trend towards exacerbated clinical manifestations was found in HEV RNA-positive patients relative to HEV RNA-negative patients. CONCLUSIONS: An elevated rate of G1 RNA was detected. Hepatitis E seems to be a neglected disease in Mexico and epidemic strains of HEV are likely to play a role as causative agents of acute hepatitis in highly exposed children. Although HAV is endemic in Mexico, an HEV-RNA detection rate of 17% in co-infected samples shows the need for screening for HEV as a part of future vaccination strategies.

Hepatitis E Virus: Still an Enigma in Mexico.

Based on high seroprevalence, null surveillance, and lack of diagnostics, Mexico is a high-risk region for hepatitis E Virus (HEV) infection. However, few local news on infection are available. Clinicians and general population are in need of increasing awareness, and preventive measures should be emphasized.