Antimicrobial resistance bacteria are nowadays ubiquitous. Its presence has been reported in almost every type of source, from water for agricultural and recreative use, water distribution pipes, and wastewater, to food, fomites, and clinical samples. Enterobacteriaceae, especially Escherichia coli, are not the exception, showing an increased resistance to several antibiotics, causing a global health and economic burden. Therefore, the monitoring of fecal microbiota is important because it is present in numerous reservoirs where gene transfer between commensal and virulent bacteria can take place, representing a potential source of resistant E. coli. In this work, antibiotic resistance profiles of 150 E. coli isolates from environmental, animal, and human samples, collected in three rural areas in Panama, were analyzed. A total of 116 isolates were resistant to at least one of the nine antibiotics tested. Remarkably, almost 100% of these exhibited resistance to tetracycline. Plasmid-associated tetA and tetB genes were detected in 42.86% of the isolates analyzed, tetA being the most prevalent. These results suggest that tetracycline resistance would be used as a convenient indicator of genetic horizontal transfer within a community.

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.

Los humedales artificiales son tecnologías que aprovechan la capacidad de depuración de las plantas y su capacidad para mejorar la calidad y el estado de los cuerpos de agua, conocida como fitorremediación. Las aplicaciones en el tratamiento de agua de distintas procedencias son amplias. Dentro de esta gama de aplicaciones destacan los Humedales Artificiales Flotantes (HAF) como soluciones innovadoras con un potencial de tratamiento mayor al de otros métodos convencionales de fitorremediación. Esta reseña presenta las posibles ventajas de su implementación en ríos urbanos, especialmente en la ciudad de Panama. Los HAF como micro ecosistemas se recomiendan como alternativa verde para el tratamiento de estos ríos con la consecuente mejora de la calidad de vida de los habitantes y el entorno.

Untreated water bodies are critical ecological niches where environmental conditions can drive the adaptive evolution of bacterial populations, enabling them to acquire new traits such as antibiotic-resistance genes. Escherichia coli is typically a commensal bacterium but can evolve into a pathogenic form, known as Diarrheagenic E. coli, responsible for both intestinal and extraintestinal diseases. This study focuses on the characterization of E. coli isolates from water samples collected from the Matasnillo River and the influence of the Juan Díaz Wastewater Treatment Plant (WWTP). While isolates from the Matasnillo River were classified as commensal, 18% of the isolates from the WWTP belonged to either phylogroups D or B2. Pathotype analysis revealed the presence of Entero-Toxigenic and Entero-Hemorrhagic E. coli in the WWTP. Moreover, Matasnillo River isolates exhibited resistance mainly to the quinolone ciprofloxacin, whereas those from the WWTP influent showed resistance to multiple broad-spectrum antibiotics. Sequencing analysis revealed the prevalence of the transmissible quinolone resistance qnrB19 among the Matasnillo River isolates and mutations conferring resistance to quinolone in gyrA, parC, and parE. These findings highlight the importance of monitoring antibiotic-resistant bacterial contamination in both freshwater and wastewater to mitigate the risk of the spread of resistant pathogens and potential epidemic outbreaks.

Background: Given the increasing problem of antibiotic resistance in A. baumannii, this study examines in vitro how combinations of colistin, meropenem, and sulbactam influence the expression of genes associated with multiresistance in this pathogen. Methods: Three multidrug-resistant strains, isolated from clinical infections in Panama (2022–2023), were identified using Vitek 2 compact. Susceptibility by broth microdilution, qualitative synergy, time-kill curves, and gene expression analysis by quantitative PCR were performed. Results: Synergistic effects were observed for the colistin–meropenem combination in all three strains, while the sulbactam–colistin combination exhibit synergy only in one of the A. baumannii isolates. Time-kill assays revealed bactericidal effects for the colistin–meropenem and sulbactam–colistin combinations. qPCR analyses indicated that colistin, meropenem, and sulbactam modified the expression of the genes under study. Colistin–meropenem and meropenem–sulbactam combinations decreased the expression of blaADC and blaOXA-51, while sulbactam–colistin did not have a significant effect. carO expression levels were not reduced with any antibiotic combination, while adeB expression was reduced with all the combinations tested. omp33–36 expression varied depending on the antibiotic and strain. Conclusions: Therefore, this study offers a new perspective on how rational combinations of clinically used antibiotics have the potential to modulate gene expression and contribute to the control of MDR strains, indicating that high-dose combination therapy with sulbactam and colistin could offer improved efficacy in treating multidrug resistant Acinetobacter baumannii infections.

Background/Objetives: The bacterial ribosome is a key target for several classes of antibiotics, including aminoglycosides, macrolides, tetracyclines, and amphenicols. Although resistance to these antibiotics is well documented in clinical settings, ribosome-targeting antibiotic resistance genes have received comparatively little attention in studies comprising aquatic environments, where research has primarily focused on β-lactams and fluoroquinolones. Moreover, while plasmid-mediated dissemination of resistance is well recognized, the chromosomal integration of resistance genes in Escherichia coli remains underexplored. Methods: In this study, E. coli isolates were recovered from two contaminated aquatic environments in Panama: surface water from the Juan Díaz River and influent wastewater from the Panama City wastewater treatment plant. Results: Overall, 80.8% of the isolates exhibited resistance to aminoglycosides, 37.4% to tetracycline, and 18.2% to chloramphenicol. Resistance genes against these antibiotics were identified via PCR, and their genomic location (plasmid or chromosome) was determined by whole-genome sequencing. Our results revealed a higher prevalence of plasmid-associated resistance genes in river isolates, while chromosomal integration was more frequent among wastewater isolates. Notably, ribosome-targeting antibiotic resistance genes were more frequently detected than those conferring resistance to β-lactams, quinolones, and sulfonamides together. Conclusions: These findings highlight distinct mechanisms underlying the dissemination of ribosome-targeting antibiotic resistance genes in aquatic environments, where pollutant pressure in surface waters may favor plasmid maintenance, while chromosomal integration may represent a strategy to reduce the fitness cost associated with plasmid carriage and ensure stable resistance persistence.