Highly Selective End-Tagged Antimicrobial Peptides Derived from PRELP

Background: Antimicrobial peptides (AMPs) are receiving increasing attention due to resistance development against conventional antibiotics. Pseudomonas aeruginosa and Staphylococcus aureus are two major pathogens involved in an array of infections such as ocular infections, cystic fibrosis, wound and post-surgery infections, and sepsis. The goal of the study was to design novel AMPs against these pathogens. Methodology and Principal Findings: Antibacterial activity was determined by radial diffusion, viable count, and minimal inhibitory concentration assays, while toxicity was evaluated by hemolysis and effects on human epithelial cells. Liposome and fluorescence studies provided mechanistic information. Protease sensitivity was evaluated after subjection to human leukocyte elastase, staphylococcal aureolysin and V8 proteinase, as well as P. aeruginosa elastase. Highly active peptides were evaluated in ex vivo skin infection models. C-terminal end-tagging by W and F amino acid residues increased antimicrobial potency of the peptide sequences GRRPRPRPRP and RRPRPRPRP, derived from proline arginine-rich and leucine-rich repeat protein (PRELP). The optimized peptides were antimicrobial against a range of Gram-positive S. aureus and Gram-negative P. aeruginosa clinical isolates, also in the presence of human plasma and blood. Simultaneously, they showed low toxicity against mammalian cells. Particularly W-tagged peptides displayed stability against P. aeruginosa elastase, and S. aureus V8 proteinase and aureolysin, and the peptide RRPRPRPRPWWWW-NH2 was effective against various "superbugs'' including vancomycin-resistant enterococci, multi-drug resistant P. aeruginosa, and methicillin-resistant S. aureus, as well as demonstrated efficiency in an ex vivo skin wound model of S. aureus and P. aeruginosa infection. Conclusions/Significance: Hydrophobic C-terminal end-tagging of the cationic sequence RRPRPRPRP generates highly selective AMPs with potent activity against multiresistant bacteria and efficiency in ex vivo wound infection models. A precise "tuning'' of toxicity and proteolytic stability may be achieved by changing tag-length and adding W-or F-amino acid tags

A multicentre study of the in-vitro activity of cefotaxime, cefuroxime, ceftazidime, ofloxacin and ciprofloxacin against blood and urinary pathogens.

The in-vitro susceptibilities of aerobic bacteria isolated from 1804 blood and 4529 urine specimens collected at nine hospitals in the UK were examined. An agar dilution method was used to determine the MICs of each isolate to three cephalosporins, cefotaxime, cefuroxime and ceftazidime, and to two fluoroquinolones, ofloxacin and ciprofloxacin. Sensitivities were then calculated using British Society for Antimicrobial Chemotherapy recommended breakpoints. Of the cephalosporins tested cefotaxime was the most active against the Enterobacteriaceae. All the systemic staphylococcus isolates collected were sensitive to both cefotaxime and cefuroxime. As expected, ceftazidime was the only cephalosporin active against the Pseudomonas isolates. Both quinolones were highly active against the Enterobacteriaceae and Pseudomonas spp. They also demonstrated good Gram-positive activity, particularly against Staphylococcus aureus and Enterococcus spp

A MULTICENTER STUDY OF THE IN-VITRO ACTIVITY OF CEFOTAXIME, CEFUROXIME, CEFTAZIDIME, OFLOXACIN AND CIPROFLOXACIN AGAINST BLOOD AND URINARY PATHOGENS

The in-vitro susceptibilities of aerobic bacteria isolated from 1804 blood and 4529 urine specimens collected at nine hospitals in the UK were examined. An agar dilution method was used to determine the MICs of each isolate to three cephalosporins, cefotaxime, cefuroxime and ceftazidime, and to two fluoroquinolones, ofloxacin and ciprofloxacin. Sensitivities were then calculated using British Society for Antimicrobial Chemotherapy recommended breakpoints. Of the cephalosporins tested cefotaxime was the most active against the Enterobacteriaceae. All the systemic staphylococcus isolates collected were sensitive to both cefotaxime and cefuroxime. As expected, ceftazidime was the only cephalosporin active against the Pseudomonas isolates. Both quinolones were highly active against the Enterobacteriaceae and Pseudomonas spp. They also demonstrated good Gram-positive activity, particularly against Staphylococcus aureus and Enterococcus spp

A multicentre study of the in-vitro activity of cefotaxime, cefuroxime, ceftazidime, ofloxacin and ciprofloxacin against blood and urinary pathogens.

The in-vitro susceptibilities of aerobic bacteria isolated from 1804 blood and 4529 urine specimens collected at nine hospitals in the UK were examined. An agar dilution method was used to determine the MICs of each isolate to three cephalosporins, cefotaxime, cefuroxime and ceftazidime, and to two fluoroquinolones, ofloxacin and ciprofloxacin. Sensitivities were then calculated using British Society for Antimicrobial Chemotherapy recommended breakpoints. Of the cephalosporins tested cefotaxime was the most active against the Enterobacteriaceae. All the systemic staphylococcus isolates collected were sensitive to both cefotaxime and cefuroxime. As expected, ceftazidime was the only cephalosporin active against the Pseudomonas isolates. Both quinolones were highly active against the Enterobacteriaceae and Pseudomonas spp. They also demonstrated good Gram-positive activity, particularly against Staphylococcus aureus and Enterococcus spp

Role of House Flies in the Ecology of Enterococcus faecalis from Wastewater Treatment Facilities.

Citation: Doud, C. W., Scott, H. M., & Zurek, L. (2014). Role of House Flies in the Ecology of Enterococcus faecalis from Wastewater Treatment Facilities. Retrieved from http://krex.ksu.eduEnterococci are important nosocomial pathogens, with Enterococcus faecalis most commonly responsible for human infections. In this study, we used several measures to test the hypothesis that house flies, Musca domestica (L.), acquire and disseminate antibiotic-resistant and potentially virulent E. faecalis from wastewater treatment facilities (WWTF) to the surrounding urban environment. House flies and sludge fromfourWWTF (1–4) as well as house flies from three urban sites close to WWTF-1 were collected and cultured for enterococci. Enterococci were identified, quantified, screened for antibiotic resistance and virulence traits, and assessed for clonality. Of the 11 antibiotics tested, E. faecalis was most commonly resistant to tetracycline, doxycycline, streptomycin, gentamicin, and erythromycin, and these traits were intra-species horizontally transferrable by in vitro conjugation. Profiles of E. faecalis (prevalence, antibiotic resistance, and virulence traits) from each of WWTF sludge and associated house flies were similar, indicating that flies successfully acquired these bacteria from this substrate. The greatest number of E. faecalis with antibiotic resistance and virulence factors (i.e., gelatinase, cytolysin, enterococcus surface protein, and aggregation substance) originated from WWTF-1 that processed meat waste from a nearby commercial meat-processing plant, suggesting an agricultural rather than human clinical source of these isolates. E. faecalis from house flies collected from three sites 0.7–1.5 km away from WWTF-1 were also similar in their antibiotic resistance profiles; however, antibiotic resistance was significantly less frequent. Clonal diversity assessment using pulsed-field gel electrophoresis revealed the same clones of E. faecalis from sludge and house flies from WWTF-1 but not from the three urban sites close to WWTF-1. This study demonstrates that house flies acquire antibiotic-resistant enterococci from WWTF and potentially disseminate them to the surrounding environment