Multidrug-resistant bacteria present resistance mechanisms against β-lactam antibiotics, such as Extended-Spectrum Beta-lactamases (ESBL) and Metallo-β-lactamases enzymes (MBLs) which are operon encoded in Gram-negative species. Likewise, Gram-positive bacteria have evolved other mechanisms through mec genes, which encode modified penicillin-binding proteins (PBP2). This study aimed to determine the presence and spread of β-lactam antibiotic resistance genes and the microbiome circulating in Quito’s Public Transport (QTP). A total of 29 station turnstiles were swabbed to extract the surface environmental DNA. PCRs were performed to detect the presence of 13 antibiotic resistance genes and to identify and to amplify 16S rDNA for barcoding, followed by clone analysis, Sanger sequencing, and BLAST search. ESBL genes bla_TEM-1 and bla_CTX-M-1 and MBL genes bla_OXA-181 and mecA were detected along QPT stations, blaTEM being the most widely spread. Two subvariants were found for bla_TEM-1, bla_CTX-M-1, and bla_OXA-181. Almost half of the circulating bacteria found at QPT stations were common human microbiota species, including those classified by the WHO as pathogens of critical and high-priority surveillance. β-lactam antibiotic resistance genes are prevalent throughout QPT. This is the first report of bla_OXA-181 in environmental samples in Ecuador. Moreover, we detected a new putative variant of this gene. Some commensal coagulase-negative bacteria may have a role as mecA resistance reservoirs.

Escherichia coli (E. coli), especially the Shiga toxin-producing O157:H7 strain, poses severe health risks. In rural Ecuador, raw milk consumption heightens contamination risks. This study analyzed 633 raw milk samples from Pichincha and Manabí to assess E. coli O157:H7 prevalence. The samples were enriched using BHI broth, and then specific culture media were used to isolate E. coli O157:H7. The pathogen in the enriched raw milk was identified, and the isolates were specifically confirmed through the application of a newly designed qPCR assay. The novel qPCR assay demonstrated remarkable sensitivity, capable of detecting up to one copy of genetic material, and specificity (no amplification of other bacteria). An extremely high E. coli O157:H7 prevalence of 0.63 (n = 401) was detected, where the province with the highest number of positive samples was Manabí with 72.8% (n = 225/309) and 54.3% (n = 179/324) for Pichincha. In both provinces, the presence of E. coli O157:H7 contamination exhibited a favorable correlation with small-scale farms and elevated temperatures. This research provides valuable data on the microbiological contamination of E. coli O157:H7 present in raw milk, in addition to an improved method that has been demonstrated to be faster, more sensitive, and more specific than conventional and previously published methods, highlighting the associated risk of food-borne infections and pointing out potential shortcomings in the regulation of agricultural practices and the need for periodic monitoring of bacterial contamination levels with updated methods.

The production of craft beer depends on the quality and availability of yeast. However, many small breweries in developing countries face high costs due to their reliance on imported yeast strains. Developing efficient and low-cost propagation methods is therefore essential for sustainable production. A lager-type Saccharomyces cerevisiae strain (SC-Lager2) was propagated using both synthetic and low-cost alternative media. The latter was formulated with malt extract as a carbon source and yeast extract obtained from brewery by-products as a nitrogen source. A Plackett–Burman design identified significant factors influencing growth (p < 0.05), and a full factorial design (2⁴) optimized conditions. Growth kinetics and biomass yield were validated at laboratory (2 L) and pilot (83 L) scales. Maltose, yeast extract, zinc sulfate, and agitation significantly affected cell density and viability (p < 0.05). Under optimized conditions, 100% viability, a maximum cell density of 1.4 × 10¹⁰ cells/mL, and a biomass yield of 10 g/L were achieved values that were statistically higher (p < 0.05) than those obtained with the synthetic medium. The maximum specific growth rate (μ_max) increased by 52%, while doubling time decreased by 39%. Overall, the use of agro-industrial by-products reduced medium costs by approximately 65% compared to conventional synthetic formulations. The proposed low-cost medium provides a scalable, economical, and sustainable solution for yeast propagation, reducing production costs while maintaining high cell viability and performance. This approach supports the autonomy and competitiveness of the craft beer sector in developing regions.

The phenomenon of antimicrobial resistance (AMR) in cold environments, exemplified by the Antarctic, calls into question the assumption that pristine ecosystems lack clinically significant resistance genes. This study examines the molecular basis of AMR in Acinetobacter spp. Isolated from Antarctic soil, focusing on the bla_TEM and bla_SHV genes associated with extended-spectrum beta-lactamase (ESBL) production; Soil samples were collected and processed to isolate Antarctic soil bacteria. Molecular detection was then conducted using polymerase chain reaction (PCR) to identify the bacteria species by 16S rRNA/rpoB and 10 different beta-lactamase-producing genes. PCR amplicons were sequenced to confirm gene identity and analyze genetic variability. Acinetobacter baumannii were identified by both microbiological and molecular tests. Notably, both the bla_TEM and bla_SHV genes encoding the enzymes responsible for resistance to penicillins and cephalosporins were identified, indicating the presence of resistance determinants in bacteria from extreme cold ecosystems. The nucleotide sequence analysis indicated the presence of conserved ARGs, which suggest stability and the potential for horizontal gene transfer within microbial communities. These findings emphasize that AMR is not confined to human-impacted environments but can emerge and persist in remote, cold habitats, potentially facilitated by natural reservoirs and global microbial dispersal. Understanding the presence and role of AMR in extreme environments provides insights into its global dissemination and supports the development of strategies to mitigate the spread of resistance genes in both environmental and clinical contexts.

We report the first molecularly confirmed record of the zoonotic heterophyid trematode Centrocestus formosanus infecting the invasive freshwater snail Melanoides tuberculata in tropical coastal Ecuador. A total of 902 M. tuberculata was examined, and cercarial shedding was induced under laboratory conditions. Two snails (0.22%) released cercariae morphologically consistent with Heterophyidae, and subsequent PCR amplification and sequencing of the ITS2 region confirmed C. formosanus. Phylogenetic analysis using the maximum-likelihood method (GTR model, 500 bootstrap replicates) revealed high genetic similarity to reference sequences from Egypt, Vietnam, Japan, and Denmark. Our findings contribute to the knowledge of expanding of this medically important zoonotic parasite in South America and identifying M. tuberculata as a competent intermediate host in the region. Given the role of C. formosanus in fish pathology and its capacity to infect humans through the consumption of raw or undercooked freshwater fish, this record raises concerns regarding potential public health and aquaculture impacts. Further studies are warranted to assess infection prevalence, identify local fish and definitive hosts, and evaluate the zoonotic risk in Ecuadorians.

Background: Multidrug-resistant bacteria present resistance mechanisms against β-lactam antibiotics, such as Extended-Spectrum Beta-lactamases (ESBL) and Metallo-β-lactamases enzymes (MBLs) operon encoded in Gram-negative species. Likewise, Gram-positive bacteria have evolved other mechanisms through mec genes, which encode modified penicillin-binding proteins (PBP2). This study aimed to determine the presence and spread of β-lactam antibiotic resistance genes and the microbiome circulating in Quito’s Public Transport (QTP). Methods: A total of 29 station turnstiles were swabbed to extract the surface environmental DNA. PCRs were performed to detect the presence of 13 antibiotic resistance genes and to identify 16S rDNA barcoding, followed by clone analysis, Sanger sequencing and BLAST search. Results: ESBL genes blaTEM-1 and blaCTX-M-1 and MBL genes blaOXA-181 and mecA were detected along QPT stations. Two subvariants were found for blaTEM-1, blaCTX-M-1, and blaOXA-181. Almost half of the circulating bacteria found at QPT stations were common human microbiota species including those classified by the WHO as pathogens of critical and high-priority surveillance. Conclusions: β-lactam antibiotic resistance genes are widely spread throughout QPT. This is the first report of blaOXA-181 in environmental samples in Ecuador. Moreover, we detected a new putative variant of this gene. Some commensal coagulase-negative bacteria may have a role as mecA resistance reservoirs