An exhaustive cell-based screen coupled with an intracellular-induced lux-based reporter identified bioactive molecules that inhibit host cell infection by intracellular pathogens.

Introduction: Antibiotic resistance poses a critical and escalating global health crisis, leading to higher morbidity and mortality associated with infectious diseases. This problem is significantly exacerbated by intracellular bacterial pathogens, which are often shielded from conventional antibiotics and foster the emergence of persister populations. Recently, host-directed therapy (HDT) has been emerging as a promising strategy that aims to modulate host cellular processes or immune responses to enhance bacterial clearance. Nonetheless, the inherent complexity of host biology makes identifying appropriate and safe modulators challenging, unpredictable, and highly complicated. Methods: Here, we present a cell-based high-throughput screen (HTS), coupled with an intracellular-induced reporter that was used to screen a library of nearly 37,000 small molecules with potentially pharmacological activity for compounds that inhibit host cell infection by intracellular pathogens. Results and discussion: This multistage, screening protocol resulted in the identification of eight non-cytotoxic compounds that efficiently inhibited the intracellular growth of the Gram-negative bacterium