ContraFect Corporation announced presentation data showing CF-370 is highly efficacious in a neutropenic rabbit pneumonia model against an extensively-drug-resistant (XDR) strain of Pseudomonas aeruginosa (P. aeruginosa).These data were recently presented at the 33rd European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) Annual Meeting held from April 15, 2023 to April 18, 2023 in Copenhagen, Denmark. ECCMID 2023 Presentations: Oral Presentation Title: Efficacy of lysin CF-370 in addition to amikacin in a neutropenic rabbit lung infection model caused by an extensively drug-resistant (XDR) P. aeruginosa In this challenging model of pulmonary infection, neutropenic animals are treated with dose regimens of amikacin and CF-370 administered alone and CF-370 administered as both a single dose and in multiple doses in addition to amikacin. Amikacin alone did not demonstrate a significant reduction in bacterial density in the lungs compared to the vehicle controls (as expected for this amikacin-resistant strain).

However, a single dose of CF-370 alone, and in addition to amikacin, significantly reduced bacteria counts compared to vehicle controls. The most significant reductions in bacterial density occurred with the administration of multiple doses of CF-370 in addition to amikacin were seen compared to all other treatment arms (p=0.0018 vs. amikacin alone, p=0.0083 vs.

CF-370 alone, and p=0.0279 vs. CF-370 single dose + amikacin). Poster Presentation Title: Activity of lysin CF-370 at the cell envelope of Gram-negative (GN) ESKAPE pathogens revealed by electron microscopy In this study, the impact of CF-370 treatment on the surface ultrastructure of P. aeruginosa, Klebsiella pneumoniae (K. pneumoniae), Acinetobacter baumannii (A. baumannii), Escherichia coli (E. coli), Enterobacter cloacae (E. cloacae) and Stenotrophomonas maltophilia (S. maltophilia) was studied with and without the presence of human serum using electron microscopy (EM).

The EM analysis elucidates that the mechanism of CF-370's potent bacteriolytic activity against these Gram-negative pathogens is based on rapid cell wall destabilization followed by pore formation and lysis. Poster Presentation Title: Bacteriolytic and anti-virulence activities of engineered lysin CF-370 against Gram-negative (GN) ESKAPE pathogens In this study, membrane permeability assays were used to demonstrate the capacity of CF-370 to disrupt the outer membrane and depolarize the inner membrane of P. aeruginosa, K. pneumoniae, A. baumannii, E. coli, E. cloacae and S. maltophilia. Furthermore, the membrane depolarization caused by CF-370, even at sub-lethal concentrations, demonstrates anti-virulence effects of impaired swarming motility and the prevention of biofilm formation.

Poster Presentation Title: Lysin exebacase exerts potent in vitro bactericidal activity against Staphylococcus aureus strains associated with pulmonary exacerbations (PExs) of cystic fibrosis (CF) In this in vitro study, exebacase was profiled against clinical Staphylococcus aureus (S. aureus) isolates from patients with CF. Minimum inhibitory concentration, minimum biofilm eradication concentration and time-kill assays were utilized. Exebacase demonstrated potent in vitro anti-staphylococcal activity against all CF patient isolates, including antibiotic-resistant colonies.

Antibiofilm activity was also observed.