Food and Drinking Water as Sources of Pathogenic Protozoans: An Update

Development of a single-cell cloning technique for isolation of Pentatrichomonas hominis: a promising tool for diagnosing Trichomonas spp. infections in the pig breeding industry

BACKGROUND

Pig breeding is a crucial sector of the global economy, playing a significant role in meat production. However, the prevalence of Trichomonas spp., a group of parasites known to induce diarrhea in various hosts, presents significant challenges in breeding facilities. These parasites pose a substantial threat to the pig breeding industry. Furthermore, despite its prevalence, diagnosing Trichomonas spp. is often challenging, primarily owing to the presence of mixed infections involving different species within clinical samples. To address this concern, we developed a novel isolation method that combines a single-cell isolation culture technique with an antimicrobial drug susceptibility test.

METHODS

Trichomonas was isolated and cultured by using the established single-worm separation technology combined with antibacterial drug screening method, and it was identified as Pentatrichomonas hominis by molecular biological identification and morphological identification. The in vitro culture conditions of the isolate were optimized to establish a stable in vitro culture system.

RESULTS

The method developed in this study was effective in successfully isolating a pure species of trichomonad from fecal samples obtained from weaned piglets in Guangdong Province. By optimizing important variables such as the culture medium, serum type, and inoculum quantity, we established a stable in vitro culture system utilizing a modified Diamond medium supplemented with 10% Procell fetal bovine serum without the use of antibiotics. Subsequent analysis of the isolate's 18S rRNA gene, ITS1-5.8S rRNA-ITS2 gene, and EF-α gene, through polymerase chain reaction, DNA sequencing, and phylogenetic analysis, revealed its close association to Pentatrichomonas hominis. Light microscopy and scanning electron microscopy demonstrated the presence of various distinct cellular structures, including four anterior flagella, recurrent flagellum, undulating membrane, pelta and axostyle. Additionally, transmission electron microscopy revealed the existence of organelles such as the Golgi complex, rough endoplasmic reticulum, food vacuoles, and hydrogenosomes. This study represents the first successful isolation of monoclonal cells of P. hominis to our knowledge and serves as a valuable baseline for future research focused on the isolation and purification of various other parasites. Additionally, it offers practical guidance for the diagnosis and management of Trichomonas spp. infections in pigs.

CONCLUSIONS

In summary, our findings underscore the efficacy of our novel isolation technique as a valuable tool for the diagnosis and management of Trichomonas spp. infections, which can help mitigate the significant economic losses encountered in the pig breeding industry.

In silico evaluation of N-aryl-1,10-phenanthroline-2-amines as potential inhibitors of T. cruzi GP63 zinc-metalloprotease by docking and molecular dynamics simulations

Based on the in vitro trypanocidal efficacy of previously synthesized N-aryl-1,10-phenanthroline-2-amines (Phen1-20) (aryl = R-phenyl, 1- or 2-naphthyl), we explored the potential interactions of these derivatives as ligands of our comparative model of T. cruzi GP63 (TcGP63). This surface metalloprotease plays a crucial role in parasite adhesion to host cells and aids in cell invasion during T. cruzi infection in Chagas disease. Ligand-protein consensus docking simulations using four GOLD scoring functions revealed that N-(R-phenyl) derivatives (R = CH3, OCH3, CF3, CN, NO2, F, Cl, and Br) presented poses with higher fitness scores than the N-naphthyl ones, with the six para-substituted derivatives (Phen4, p-CH3; Phen7, p-OCH3; Phen10, p-CN; Phen14, p-F; Phen17, p-Cl; and Phen18, p-Br) being more favorable than the ortho or meta ones. Subsequent aqueous molecular dynamics simulation (GROMACS package, CHARMM36 force field, and TIP3P water model) of the ligand-protein complexes for these six top-ranking compounds showed persistent interactions within the TcGP63 active site, primarily through coordination with Zn(II)-cofactor, and H-bonding with catalytic Glu221 and zinc-binding His224. RMSD and RMSF analyses confirmed the stability of these interactions, particularly for compounds with electron-withdrawing groups by inductive effect as R-substituents, such as p-OCH3 (Phen7) and p-CN (Phen10). Binding free energy calculations by the linear interaction energy (LIE) approach corroborated the favorable interactions observed in simulations, highlighting Phen7 and Phen10 as the most promising candidates. This study underscores the potential of N-phenyl-1,10-phenanthroline-2-amines as putative inhibitors targeting the T. cruzi GP63 enzyme.

Preparation and Antibacterial Performance Study of CeO2/g-C3N4 Nanocomposite Materials

In response to the challenges of food spoilage and water pollution caused by pathogenic microorganisms, CeO2/g-C3N4 nanocomposites were synthesized via one-step calcination using thiourea and urea as precursors. Steady-state photoluminescence (PL) spectroscopy analysis demonstrated that 8 wt% CeO2/g-C3N4 exhibited superior electron-hole separation efficiency. Quantitative antimicrobial assays demonstrated that the nanocomposites displayed enhanced bactericidal activity against Escherichia coli, Ralstonia solanacearum, and Staphylococcus aureus. Electron paramagnetic resonance (EPR) spectroscopy analysis verified the generation of hydroxyl radicals (·OH) and superoxide radicals (·O2-) during the photo-Fenton process utilizing CeO2/g-C3N4 nanocomposites. Additionally, 8 wt% CeO2/g-C3N4 nanocomposites demonstrated enhanced photocatalytic degradation of rhodamine B (RhB) and tetracycline hydrochloride (TC) under photo-Fenton conditions.

Detection of Gastrointestinal Pathogens with Zoonotic Potential in Horses Used in Free-Riding Activities during a Countrywide Study in Greece

The objectives of this study were (a) to detect zoonotic gastrointestinal pathogens in faecal samples of horses using the FilmArray® GI Panel and (b) to identify variables potentially associated with their presence. Faecal samples collected from 224 horses obtained during a countrywide study in Greece were tested by means of the BioFire® FilmArray® Gastrointestinal (GI) Panel, which uses multiplex-PCR technology for the detection of 22 pathogens. Gastrointestinal pathogens were detected in the faecal samples obtained from 97 horses (43.3%). Zoonotic pathogens were detected more frequently in samples from horses in courtyard housing (56.0%) than in samples from horses in other housing types (39.7%) (p = 0.040). The most frequently detected zoonotic pathogens were enteropathogenic Escherichia coli (19.2% of horses) and Shiga-like toxin-producing E. coli stx1/stx2 (13.8%). During multivariable analysis, two variables emerged as significant predictors for the outcome 'detection of at least one zoonotic pathogen in the faecal sample from an animal': (a) the decreasing age of horses (p = 0.0001) and (b) the presence of livestock at the same premises as the horses (p = 0.013). As a significant predictor for the outcome 'detection of two zoonotic pathogens concurrently in the faecal sample from an animal', only the season of sampling of animals (autumn) emerged as significant in the multivariable analysis (p = 0.049). The results indicated a diversity of gastrointestinal pathogens with zoonotic potential in horses and provided evidence for predictors for the infections; also, they can serve to inform horse owners and handlers regarding the possible risk of transmission of pathogens with zoonotic potential. In addition, our findings highlight the importance of continuous surveillance for zoonotic pathogens in domestic animals.