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Antimicrobial resistance in Acinetobacter baumannii poses a significant global health challenge. Phage therapy, particularly through phage-antibiotic synergy (PAS), offers a promising strategy to combat this pathogen. This study demonstrated significant PAS, where the combination of phage Indie and ceftazidime achieved a bacterial reduction of more than 85% of A. baumannii strain AbAK03 at 17 h using low doses. Notably, this combination overcame phage resistance observed at 4 h when the phage was used alone, extending bacterial eradication by 13 h. Furthermore, phage Indie restored bacterial susceptibility to ceftazidime, supporting its role in improving interventional treatments against multidrug-resistant A. baumannii . To explore this interaction, phage Indie was isolated and characterized from multidrug-resistant clinical strains. An in vitro PAS experiment was performed using ceftazidime and piperacillin-tazobactam. The combination of phage Indie with ceftazidime consistently showed superior bactericidal effects compared to either agent alone, while the combination of phage Indie with piperacillin-tazobactam exhibited an antagonistic effect. These findings provide clear evidence supporting the application of phage-antibiotic combinations as an effective intervention strategy and lay the groundwork for future in vivo trials in a mouse model to combat antimicrobial resistance.

Acinetobacter baumannii is an opportunistic pathogen and a major cause of nosocomial infections worldwide. This study aimed to isolate and characterize phages with lytic activity against multidrug-resistant A. baumannii strains to enable antibacterial alternatives. Eight phages (AKO8a, PS118, B612, MCR, IDQ7, 89P13, CRL20, and CIM23) were isolated and subjected to genomic, phylogenetic, and functional analyses. Antibacterial activity was assessed in vitro against A. baumannii strain AbAK04 by measuring optical density over 17 h at multiplicities of infection (MOIs) of 0.1, 1, and 10, using a repeated-measures design with time as a crossed factor and MOI as a nested factor. Tukey’s post-hoc test identified significant bacterial growth reductions of 57–72% (p < 0.001). Specifically, phages PS118 and 89P13 reduced growth by 71% at MOI 10; CIM23, B612, and CRL20 achieved 68% reduction at MOI 1; and MCR reduced growth by 64% at MOIs 0.1 and 1. Notably, lytic phage MCR encodes a glycosyl hydrolase family 58 (GH58) enzyme, potentially contributing to its antibacterial activity. Genomic analyses confirmed absence of virulence and antibiotic resistance genes, with all phages classified as novel species within the Kagunavirus genus. These findings support the use of these phages as promising candidates for in vivo evaluation.

Acute hepatopancreatic necrosis disease (AHPND) is a severe disease affecting recently stocked cultured shrimps. The disease is mainly caused by V. parahaemolyticus that harbors the pVA1 plasmid; this plasmid contains the pirA and pirB genes, which encode a delta-endotoxin. AHPND originated in China in 2009 and has since spread to several other Asian countries and recently to Latin America (2013). Many Asian strains have been sequenced, and their sequences are publicly accessible in scientific databases, but only four strains from Latin America have been reported. In this study, we analyzed nine pVA1-harboring V. parahaemolyticus sequences from strains isolated in Mexico along with the 38 previously available pVA1-harboring V. parahaemolyticus sequences and the reference strain RIMD 2210633. The studied sequences were clustered into three phylogenetic clades (Latin American, Malaysian, and Cosmopolitan) through pangenomic and phylogenomic analysis. The nucleotide sequence alignment of the pVA1 plasmids harbored by the Asian and Latin American strains confirmed that the main structural difference in the plasmid between the Asian and Latin American strains is the absence of the Tn3 transposon in the Asian strains; in addition, some deletions in the pirAB region were found in two of the Latin American strains. Our study represents the most robust and inclusive phylogenomic analysis of pVA1-harboring V. parahaemolyticus conducted to date and provides insight into the epidemiology of AHPND. In addition, this study highlights that disease diagnosis through the detection of the pirA and pirB genes is an inadequate approach due to the instability of these genes.

A rise in foodborne outbreaks in the United States associated with fresh produce has resulted in increased concerns with the importation of fruits and vegetables. Mexico is a major exporter of produce to the United States, particularly tomatoes and bell peppers. A quantitative microbial risk assessment (QMRA) was conducted to evaluate the public health impact of protozoan-laden water irrigating produce in Culiacan, Sinaloa, Mexico. Specifically, a QMRA was conducted to address the human health impact associated with consumption of tomatoes, bell peppers, cucumbers, and lettuce irrigated with water contaminated with Cryptosporidium and Giardia. Yearly infection risks were estimated and assumed a 120-day exposure in a given year. Annual risks range from 9 × 10(−6) for Cryptosporidium at the lowest concentration associated with bell peppers to almost 2 × 10(−1) for exposure to Giardia on lettuce at the highest detected concentration. With the relatively high number of illnesses resulting from produce-related outbreaks, addressing pre- and postharvest points of contamination for fruits and vegetables consumed raw should be a food industry priority. This research shows how QMRA can be used to interpret microbial contamination data for public health significance and subsequently provide the foundation for guideline development.

Introduction: Salmonella is a major foodborne pathogen widely distributed in the environment. Surface water, soil, and sediments may confer a protective effect on Salmonella against non-host conditions. Methodology: This study focused on determining the prevalence of Salmonella spp. in river sediments from Sinaloa central region by the Most Probable Number (MPN) technique and determining the antimicrobial resistance profile by Kirby-Bauer assay. Results: Results showed the prevalence of Salmonella from 37.5 to 62.5% of the samples, oscillating from 0.322 to 20 MPN/4g, with August being the month with the highest levels. In silico geno-serotyping reveals the presence of Salmonella serotypes Typhi, Javiana, Ohio, Montevideo, Oranienburg, Pomona, Agona, Livingstone, Weltevreden, Anatum, and Minnesota. The most prevalent serotypes in river sediments were Pomona, Montevideo, and Oranienburg. Almost all isolates showed resistance to erythromycin, rifampin, and penicillin. Conclusions: This study reveals the prevalence and distribution of Salmonella enterica in river sediments, which may represent a potential niche for establishment and survival in the environment and become a potential contamination source.

The Enterobacter cloacae complex, a prominent bacterium responsible worldwide for most bloodstream infections in the hospital environment, has shown broad-spectrum antibiotic resistance, including carbapenems. Therefore, bacteriophages have again attracted the attention of the science and medical community as an alternative to control Multidrug resistant bacteria. In this study, water samples from Río Abajo River, in Panama City, Panama, were collected, for phage isolation, purification, characterization and propagation against the E . cloacae complex. As result, a phage produced clear and round plaque-forming units indicating a lytic phage was isolated. Further analyses concluded that this phage is stable at temperatures between 25°C and 50°C, it remains infective in a pH range between 7 to 11, with high sensitivity to Ultraviolet light. Remarkedly, it exhibits a narrow host specificity only infecting E . cloacae . Whole genome sequencing revealed that is a myovirus with a genome size of 178,477 bp, a G-C content of 45.8%, and containing approximately 294 genes. Among them, protein-encoding genes involved in morphology, inactivation, adsorption to cells, DNA injection and lytic enzymes were identified. Additionally, the genome contained two tRNA sequences. Genes that encode holins and endolysins, typical of lytic bacteriophages, were also present. A whole-genome sequencing analysis indicated that, according to the genus demarcation criteria, this phage belongs to a novel species within the Family Straboviridae , called genus Pseudotevenvirus .

Abstract Salmonella remains the leading cause of foodborne infections globally. Environmental reservoirs, particularly aquatic bodies, serve as conduits for the fecal–oral transmission of this pathogen. While the gastrointestinal tract is traditionally considered the primary habitat of Salmonella, mounting evidence suggests the bacterium’s capacity for survival in external environments. The application of advanced technological platforms, such as next-generation sequencing, facilitates a comprehensive analysis of Salmonella’s genomic features. This study aims to characterize the genomic composition of Salmonella isolates from river water, contributing to a potential paradigm shift and advancing public health protection. A total of 25 river water samples were collected and processed, followed by microbiological isolation of Salmonella strains, which were then sequenced. Genomic characterization revealed adaptive mechanisms, including gene duplication. Furthermore, an open pangenome, predisposed to incorporating foreign genetic material, was identified. Notably, antibiotic resistance genes were found to be part of the core genome, challenging previous reports that placed them in the accessory genome. Salmonella exhibits genomic characteristics for environmental survival and an open pangenome.

Objective: The aim of this work was to analyze the metadata of the SARS-CoV-2 sequences obtained from samples collected in Mexico from 2020 to 2022. Materials and Methods: Metadata of SARS-CoV-2 sequences from samples collected in Mexico up to 31 December 2022 was retrieved from GISAID and manually cured for interpretation. Results: As of December 2022, Mexican health authorities and the scientific community have sequenced up to 81,983 SARS-CoV-2 viral genomes deposited in GISAID, representing 1.1% of confirmed cases. The number of sequences obtained per state corresponded to the gross domestic product (GDP) of each state for the first (Mexico City) and the last (Tlaxcala). Approximately 25% of the sequences were obtained from CoViGen-Mex, an interdisciplinary initiative of health and scientific institutions to collect and sequence samples nationwide. The metadata showed a clear dominance of sequences retrieved by women. A similar variant distribution over time was found in Mexico and overseas, with the Omicron variant predominating. Finally, the age group with the highest representation in the sequences was adults aged 21 to 50 years, accounting for more than 50% of the total. Conclusions: Mexico presents diverse sociodemographic and economic characteristics. The COVID-19 pandemic has been and continues to be a challenge for collaboration across the country and around the world.

Annona muricata L. is a tropical tree that is used in traditional medicine around the world. The high content of flavonoid, alkaloid, acetogenin, phenolic and lipophilic compounds of this tropical tree forms the basis of its traditional medical uses. Our objective was to study soursop leaf extracts to support their use as antiviral therapies and investigate their protective effects against oxidative damage. The aqueous extract (AE) and acidified ethanolic extract (AEE) of soursop leaves were characterized by ultra performance liquid chromatography (UPLC), and their effects on human erythrocytes and in vitro antioxidant capacity, as evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays, were investigated. The antiviral effects were evaluated using a bacteriophage surrogate. AEE showed the highest phenolic content, with rutin as the predominant compound. This extract showed higher values in the DPPH and ABTS assays, with 23.61 ± 0.42 and 24.91 ± 0.16 mmol of Trolox equivalent per gram, respectively. Inhibition of hemolysis was 34% and 51% for AE and AEE, respectively. AEE was selected for the antiviral study because of its higher antioxidant activity. The viral reduction ranged from 5–6 log10 plaque-forming units/volume (PFU) at contact times of 15–360 min. Soursop leaves have a positive effect on reducing oxidative stress in human erythrocytes and viral infections.

The study objective was to evaluate human faecal contamination impacts in the Yal-ku lagoon in the Mexican Caribbean and to estimate adenovirus infection and illness risks associated with recreational exposure during water activities. A total of 20 water samples (10 from each site × two sites) (50 L) were collected monthly over a period of 12 months from two selected sampling sites in the swimming area of the Yal-ku lagoon. The occurrence of faecal-associated viruses was explored, and human adenovirus (HAdV) and pepper mild mottle virus (PMMoV) concentrations were quantified. A quantitative microbial risk assessment (QMRA) model was used to estimate exposure and subsequent adenovirus infection and illness risk for 1 h of swimming or snorkelling. Somatic and F + -specific coliphages occurred in 100% of the samples. Both HAdV and PMMoV were detected at a 60% frequency thereby indicating persistent faecal inputs. PMMoV concentrations (44–370 GC/L) were relatively lower than the concentrations of HAdV (64–1,000 GC/L). Estimated mean adenovirus risks were greater for snorkelling than for swimming by roughly one to two orders of magnitude and estimated mean illness risks for snorkelling were >32/1,000. Human faecal contamination is frequent in the Yal-ku lagoon, which is associated with human gastrointestinal illness.