The present disclosure describes screening cord blood for antibacterial activity against L-form bacteria, methods of treating a patient having an L-form bacterial infection using a cord blood agent, and methods of killing or inhibiting L-form bacteria in an in vitro or ex vivo setting. L-form bacteria underlying an L-form bacterial infection are isolated from a subject having an infection and are altered to a culturable morphology. A set of cord blood agents are screened against the isolated L-form bacteria to identify one or more cord blood agents usable as effective treatment agents.
