An Gram negative strain of S. maltophilia, indigenous to environments contaminated by Cr(VI) and identified by biochemical methods and 16S rRNA gene analysis, reduced chromate by 100%, 98–99% and 92% at concentrations in the 10–70, 80–300, and 500 mg/L range, respectively at pH 7 and temperature 37 °C. Increasing concentrations of Cr(VI) in the medium lowered the growth rate but could not be directly correlated with the amount of Cr(VI) reduced. The strain also exhibited multiple resistance to antibiotics and tolerance and resistance to various heavy metals (Ni, Zn and Cu), with the exception of Hg. Hexavalent chromium reduction was mainly associated with the soluble fraction of the cell evaluated with crude cell-free extracts. A protein of molecular weight around 25 kDa was detected on SDS-PAGE gel depending on the concentration of hexavalent chromium in the medium (0, 100 and 500 mg/L). In silico analysis in this contribution, revealed the presence of the chromate reductase gene ChrR in S. maltophilia, evidenced through a fragment of around 468 bp obtained experimentally. High Cr(VI) concentration resistance and high Cr(VI) reducing ability of the strain make it a suitable candidate for bioremediation.

Ibuprofen (IBU) and Diclofenac (DIC) are non-steroidal anti-inflammatory drug which have shown to have broad antimicrobial activity and limit biofilm formation. Aim of this study was to evaluate the effects of IBU and DIC against biofilm formation strong strains Escherichia coli and Klebsiella pneumoniae associated with urinary tract infections (UTIs). Additionally some virulence factors, antibiotic resistance, ESBL production were estimated to find correlation with the biofilm production and acil homoserine lactone (AHL). Our results suggest that IBU and DIC, could be useful in the treatment of urinary tract infections caused by E. coli and K. pneumoniae. IBU with CMIB 8, 30 and 125 mg/L, caused dramatic reductions in some cases and inhibited virulence factors which changes in the morphotypes expressed on congo red agar. DIC with CMIB 30 and 50 mg/L caused reductions in biofilm formation 50.1%. In this study, were evidenced the relationship between virulence factors, production of AHL and multi drugs resistance with biofilm production. Key words: Diclofenac, ibuprofen, biofilm, acil homoserine lactone (AHL), Escherichia coli, Klebsiella pneumoniae.

FimH is a type I fimbria of uropathogenic Escherichia coli (UPEC), recognized for its ability to adhere and infect epithelial urinary tissue. Due to its role in the virulence of UPEC, several therapeutic strategies have focused on the study of FimH, including vaccines, mannosides, and molecules that inhibit their assembly. This work has focused on the ability of a set of monosubstituted and disubstituted phenyl mannosides to inhibit FimH. To determine the 3D structure of FimH for our in silico studies, we obtained fifteen sequences by PCR amplification of the fimH gene from 102 UPEC isolates. The fimH sequences in BLAST had a high homology (97–100%) to our UPEC fimH sequences. A search for the three-dimensional crystallographic structure of FimH proteins in the PDB server showed that proteins 4X5P and 4XO9 were found in 10 of the 15 isolates, presenting a 67% influx among our UPEC isolates. We focused on these two proteins to study the stability, free energy, and the interactions with different mannoside ligands. We found that the interactions with the residues of aspartic acid (ASP 54) and glutamine (GLN 133) were significant to the binding stability. The ligands assessed demonstrated high binding affinity and stability with the lectin domain of FimH proteins during the molecular dynamic simulations, based on MM-PBSA analysis. Therefore, our results suggest the potential utility of phenyl mannoside derivatives as FimH inhibitors to mitigate urinary tract infections produced by UPEC; thus, decreasing colonization, disease burden, and the costs of medical care.

The new coronavirus SARS-CoV-2 that causes different infections in humans has become a challenge for humanity because it has caused many deaths worldwide. This new virus is considered as a zoonotic infectious particle, the clear mechanisms of the pathogenicity and transmissibility of this virus are not exactly known. Therefore, here some characteristics of a possible transmission are analyzed for house flies.

Silver nanoparticles were biosynthesized using the culture supernatant of Staphylococcus sp. YRA, a strain isolated from Colombian mining sediments. Synthesis was optimized at 1 mM AgNO₃, pH 7, 40 °C and 7 μg/mL extract, producing spherical, protein-capped AgNPs with primary sizes in the tens-of-nanometers range (~35–90 nm by SEM), while DLS indicated larger hydrodynamic diameters (~250–320 nm) consistent with aggregation in suspension (ζ-potential −16.6 mV). These nanoparticles remained stable over 6 months. Characterization by UV–Vis, SEM, AFM, EDS and FTIR confirmed extracellular protein-mediated reduction and capping. The AgNPs showed antibacterial activity against multidrug-resistant clinical isolates (Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Salmonella bongori, Enterococcus spp.), with inhibition zones of 8–16 mm at 400–1000 μg/mL. Biofilm formation was reduced by >50% at 700 μg/mL in both Gram-positive and Gram-negative strains. In Phaseolus vulgaris (P. vulgaris), low concentrations (5–100 μg/mL) increased growth and chlorophyll content, while 500 μg/mL caused moderate inhibition. FTIR analysis identified amide and thiol groups from bacterial enzymes as capping agents. These results suggest Staphylococcus sp. YRA as a bacterial platform for AgNPs production with antibiofilm activity against MDR pathogens and acceptable phytotoxicity profile for potential applications.