Introduction: One of the main issues in the medical field and clinical practice is the development of novel and effective treatments against infections caused by antibiotic-resistant bacteria. One avenue that has been approached to develop effective antimicrobials is the use of silver nanoparticles (Ag-NPs), since they have been found to exhibit an efficient and wide spectrum of antimicrobial properties. Among the main drawbacks of using Ag-NPs are their potential cytotoxicity against eukaryotic cells and the latent environmental toxicity of their synthesis methods. Therefore, diverse green synthesis methods, which involve the use of environmentally friendly plant extracts as reductive and capping agents, have become attractive to synthesize Ag-NPs that exhibit antimicrobial effects against resistant bacteria at concentrations below toxicity thresholds for eukaryotic cells. Purpose: In this study, we report a green one-pot synthesis method that uses Acacia rigidula extract as a reducing and capping agent, to produce Ag-NPs with applications as therapeutic agents to treat infections in vivo. Materials and methods: The Ag-NPs were characterized using transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction, energy-dispersive spectroscopy, ultraviolet–visible, and Fourier transform infrared. Results: We show that Ag-NPs are spherical with a narrow size distribution. The Ag-NPs show antimicrobial activities in vitro against Gram-negative (Escherichia coli, Pseudomonas aeruginosa, and a clinical multidrug-resistant strain of P. aeruginosa) and Gram-positive (Bacillus subtilis) bacteria. Moreover, antimicrobial effects of the Ag-NPs, against a resistant P. aeruginosa clinical strain, were tested in a murine skin infection model. The results demonstrate that the Ag-NPs reported in this work are capable of eradicating pathogenic resistant bacteria in an infection in vivo. In addition, skin, liver, and kidney damage profiles were monitored in the murine infection model, and the results demonstrate that Ag-NPs can be used safely as therapeutic agents in animal models. Conclusion: Together, these results suggest the potential use of Ag-NPs, synthesized by green chemistry methods, as therapeutic agents against infections caused by resistant and nonresistant strains.

Candidozyma auris (formerly Candida auris) is an emerging multidrug-resistant pathogenic fungus with an increased ability to cause outbreaks in healthcare facilities, leading to poor patient outcomes. Since its initial discovery in 2009, C. auris has spread rapidly across continents and is now classified by both the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) as a critical-priority pathogen. This review summarizes current knowledge on the origin, taxonomy, microbiology, and virulence mechanisms of C. auris, emphasizing its thermotolerance, osmotolerance, and biofilm-forming capacity on biotic and abiotic surfaces, as well as aspects related to its antifungal drug resistance and management. These features, together with its genomic plasticity, contribute to persistence, transmission, and drug resistance. Emerging evidence also supports a potential link between climate change and C. auris evolution, highlighting environmental adaptation as a driver of pathogenicity. Combating C. auris will require multidisciplinary efforts to mitigate its expanding global impact.

A corrigendum of this article has been published; full details can be found at [10.1099/mgen.0.001641] Discovery of novel bioactive natural products from Actinomycetota has decreased, motivating the exploration of rare ecosystems. In this work, we integrated genomics and untargeted metabolomics to profile the biosynthetic capacity of Streptomyces and Nocardia strains isolated from two contrasting, Ramsar-listed Mexican biomes with well-defined ecological features: Cuatro Ciénegas, a semi-arid, oligotrophic karst basin with high microbial endemism, and Calakmul, a tropical rainforest characterized by high biodiversity, seasonal wetlands and limestone-derived alkaline soils. We hypothesized that bacteria isolated from contrasting environments would encode for novel and distinctive subsets of secondary metabolites. Using different metabolo-genomic approaches, a diverse collection of Streptomyces and Nocardia strains was identified, including several potentially novel species. Genome mining revealed a large repertoire of biosynthetic gene clusters (BGCs), many without matches to known metabolites, while molecular networking and dereplication (GNPS, SNAP-MS) exposed extensive chemical diversity within the isolates. Targeted synteny/ortholog analyses (CORASON) linked subsets of metabolites to BGCs, confirming actinomycin and collismycin and identifying komodoquinone-, nocardiopsistin- and rubiginone-like clusters. Notably, bioactivity assays of crude extracts demonstrated effective antifungal effects against Candida albicans SC5314 biofilms and planktonic growth, suggesting their potential therapeutic use. These findings reveal a significant untapped chemical space encoded by Actinomycetota from Ramsar sites, while reinforcing the need for improved tools to connect genomic and metabolomic data for natural product discovery.

Coccidioides immitis and Coccidioides posadasii, the causative agents of coccidioidomycosis, represent a major public health concern in endemic regions of North and South America. The disease spectrum ranges from mild respiratory illness to severe disseminated infections, with thousands of cases reported annually in the United States and an increasing recognition of its global impact. Despite existing antifungal therapies, treatment remains challenging due to toxicity, drug resistance, and limited therapeutic options. High-throughput screening platforms have revolutionized drug discovery for infectious diseases; however, progress in antifungal screening for Coccidioides spp. has been hampered by the requirement for Biosafety Level 3 (BSL-3) containment. To overcome these barriers, we leveraged an attenuated C. posadasii strain that can be safely handled under BSL-2 conditions. Here, we describe the development and optimization of 96-well and 384-well plate screening methodologies, providing a safer and more efficient platform for antifungal discovery. This approach enhances the feasibility of large-scale screening efforts and may facilitate the identification of novel therapeutics for coccidioidomycosis.

Coccidioides immitis and Coccidioides posadasii, the causative agents of coccidioidomycosis, represent a major public health concern in endemic regions of North and South America. The disease spectrum ranges from mild respiratory illness to severe disseminated infections, with thousands of cases reported annually in the United States and an increasing recognition of its global impact. Despite existing antifungal therapies, treatment remains challenging due to toxicity, drug resistance, and limited therapeutic options. High-throughput screening platforms have revolutionized drug discovery for infectious diseases; however, progress in antifungal screening for Coccidioides spp. has been hampered by the requirement for Biosafety Level 3 (BSL-3) containment. To overcome these barriers, we leveraged an attenuated C. posadasii strain that can be safely handled under BSL-2 conditions. Here, we describe the development and optimization of 96-well and 384-well plate screening methodologies, providing a safer and more efficient platform for antifungal discovery. This approach enhances the feasibility of large-scale screening efforts and may facilitate the identification of novel therapeutics for coccidioidomycosis.

Candidozyma auris (formerly Candida auris) is an emerging multidrug-resistant pathogenic fungus with an increased ability to cause outbreaks in health care facilities leading to poor patient outcomes. Since its initial discovery in 2009, C.auris has spread rapidly across continents and is now classified by both the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) as a critical-priority pathogen. This review summarizes current knowledge on the origin, taxonomy, microbiology, and virulence mechanisms of C.auris, emphasizing its thermotolerance, osmotolerance, and biofilm-forming capacity on biotic and abiotic surfaces, as well as aspects related to its antifungal drug resistance and management. These features, together with its genomic plasticity, contribute to persistence, transmission, and drug resistance. Emerging evidence also supports a potential link between climate change and C. auris evolution, highlighting environmental adaptation as a driver of pathogenicity. Combating C. auris will require multidisciplinary efforts to mitigate its expanding global impact.