Comparative study of virulence potential, phylogenetic origin, CRISPR-Cas regions and drug resistance of Escherichia coli isolates from urine and other clinical materials.

Introduction: Urinary tract infections (UTI), among which the main etiological factor is uropathogenic Escherichia coli (UPEC, E. coli), remain an important issue for clinicians. The aim of the study was to demonstrate clear differences in the pathogenic properties of urine-derived E. coli compared to other extraintestinal E. coli clinical isolates (derived from: blood, lower respiratory tracts, sputum, reproductive tract, body fluids, perianal pus, other pus, wound, postoperative wound and other sources). Methods: The collection of 784 E. coli isolates was collected from various materials of hospitalized patients. They were analyzed in terms of virulence-associated genes (papC, sfaD/sfaE, cnf1, usp., fimG/H, hlyA), belonging to phylogenetic groups and the presence of CRISPR-Cas regions using PCR. In addition, the epidemiological data and the antibiotic resistance profiles provided by the hospital's microbiology department were included for statistical analyses. Results: Urine-derived E. coli showed significantly greater virulence potential compared to other isolates, but they were generally unremarkable in terms of drug resistance. The isolates most often belonged to phylogenetic group B2. Drug resistance was negatively correlated with CRISPR 2 presence and high average virulence score, but positively correlated with CRISPR 4 presence. To the best of our knowledge, we are the first to report significant differences in sputum-derived isolates-they revealed the lowest virulence potential and, at the same time, the highest drug resistance. Discussion: In conclusion, we demonstrated significant differences of urinary-derived E. coli compared to other clinical E. coli isolates. We would like to suggest excluding penicillins from use in E. coli infection at this time and monitoring strains with a high pathogenicity potential.

Magnetic nanoparticles as a drug delivery system that enhance fungicidal activity of polyene antibiotics.

This study was designed to assess the antifungal/anti-biofilm and hemolytic properties of two polyene antibiotics, amphotericin B (AMF) and nystatin (NYS), attached to the surface of magnetic nanoparticles (MNP) against clinical isolates of Candida species and human red blood cells, respectively. The developed nanosystems, MNP@AMF and MNP@NYS, displayed stronger fungicidal activity than unbound AMF or NYS. Synergistic activity was observed with a combination of polyenes and MNPs against all tested Candida strains. Nanosystems were more potent than unbound agents when tested against Candida strains in the presence of pus, and as agents able to prevent Candida biofilm formation. The observed inactivation of catalase Cat1 in Candida cells upon treatment with the nanosystems suggests that disruption of the oxidation-reduction balance is a mechanism leading to inhibition of Candida growth. The significant decrease of polyenes lytic activity against host cells after their attachment to MNPs surface indicates improvement in their biocompatibility.

Comparison of in vitro activity of doripenem, imipenem and meropenem against clinical isolates of Enterobacteriaceae, Pseudomonas and Acinetobacter in Southern Poland.

UNLABELLED: In the study we tested drug sensitivity to 3 carbapenems (doripenem, imipenem and meropenem) of Gram-negative clinical isolates from Southern Poland. MATERIAL AND METHODS: 89 strains were examined: 42 from Pseudomonas genus, 16 Acinetobacter baumannii strains and 31 Enterobacteriaceae strains. Etests were used according to the producers instructions, MIC values were interpreted using EUCAST criteria. RESULTS: Highest in vitro activity against Pseudomonas spp. was shown for doripenem, then meropenem and the lowest for imipenem (MIC values were definitely lower for doripenem; differences were statistically significant); A. baumannii strains showed similar sensitivity to doripenem, meropenem and imipenem (differences non-significant); all Enterobacteriaceae strains showed sensitivity to the tested antimicrobials. CONCLUSIONS: As a conclusion-doripenem, which has high in vitro activity (almost the same as imipenem and meropenem) as well as beneficial pharmacologic properties, may be an alternative solution in the treatment of multiresistant Gram-negative bacteria, especially in patients in severe status who require restrictive antibiotic regimens.