Antimicrobial-resistance in Escherichia coli isolatedfrom wild pheasants (Phasianus colchicus).

The purpose of this study was to examine the prevalence of antimicrobial resistance among 180 Escherichia coli strains isolated from 200 wild pheasants caught in rural areas of the Czech Republic (Eastern Moravia) and Slovakia (Western Region). The isolates were also classified into phylogenetic groups by the multiplex PCR method. Our findings demonstrated that 130 strains were resistant to ampicillin (72%), 160 strains to cephalothin (89%), and 40 strains to tetracycline (22%).

Antibiotic resistance, virulence factors and biofilm formation ability in Escherichia coli strains isolated from chicken meat and wildlife in the Czech Republic.

Attachment of pathogenic bacteria to food contact surfaces and the subsequent biofilm formation represent a serious threat for the food industry, since these bacteria are more resistant to antimicrobials or possess more virulence factors. The main aim of this study was to investigate the correlation between antibiotic resistance against 13 antibiotics, distribution of 10 virulence factors and biofilm formation in 105 Escherichia coli strains according to their origin. The high prevalence of antibiotic resistance that we have found in wildlife isolates could be acquired by horizontal transfer of resistance genes from human or domestic or farm animals.

Colicins U and Y inhibit growth of Escherichia coli strains via recognition of conserved OmpA extracellular loop 1.

Interactions of colicins U and Y with the OmpA (Outer membrane protein A) receptor molecule were studied using site-directed mutagenesis and colicin binding assay. A systematic mutagenesis of the colicin-susceptible OmpA sequence from Escherichia coli (OmpA) to the colicin-resistant OmpA sequence from Serratia marcescens (OmpA) was performed in regions corresponding to extracellular OmpA loops 1-4. Susceptibility to colicins U and Y was significantly affected by the OmpA mutation in loop 1.

Resistance and virulence factors of Escherichia coli isolated from chicken.

Chicken meat has become an important part of the human diet and besides contamination by pathogenic Escherichia coli there is a risk of antibiotic resistance spreading via the food chain. The purpose of this study was to examine the prevalence of resistance against eight antibiotics and the presence of 14 virulence factors among 75 Escherichia coli strains isolated from chicken meat in the Czech Republic after classification into phylogenetic groups by the multiplex PCR method. More than half of strains belonged to A phylogroup, next frequently represented was B1 phylogroup, which suggests the commensal strains.

Inactivation of colicin Y by intramembrane helix-helix interaction with its immunity protein.

The construction of hybrids between colicins U and Y and the mutagenesis of the colicin Y gene (cya) have revealed amino acid residues important for interactions between colicin Y and its cognate immunity protein (Cyi). Four such residues (I578, T582, Y586 and V590) were found in helices 8 and 9 of the colicin Y pore-forming domain. To verify the importance of these residues, the corresponding amino acids in the colicin B protein were mutated to the residues present in colicin Y.