Directed evolution of phage lysins

Abstract

Resistance to carbapenem, a ‘last resort’ antibiotic, has been discovered in two major nosocomial pathogens, Acinetobacter baumannii and Pseudomonas aeruginosa. The dearth of novel antibiotics being developed necessitates alternative antimicrobial approaches. Lysins are promising alternative antimicrobial agents due to their rapid bactericidal activity and low likelihood of resistance development. However, Gram-negative lysins are inhibited under physiologically relevant conditions such as in the presence of human serum/NaCl. Directed evolution may be employed to improve the activity and overcome the limitations of lysins. Though, the present lysin library screening procedure is labour-intensive and time-consuming. Therefore, we developed and validated a novel high-throughput lysin screening method. This method was effective in screening lysins activity. Additionally, we have generated a diverse library of lysin using error-prone PCR. We propose adapting this high-throughput lysin screening method to expedite the discovery of improved variants in lysin libraries.