9. Conclusion and future directions
This review represents the first time pan-pathogen antimicrobials have been formally identified and characterised, and the first time such drugs have been associated with ‘magic blanket’ antimicrobial development. Azithromycin, ivermectin, niclosamide, and nitazoxanide assert a unique advantage over traditional antibiotics and antivirals in their ability to treat a wider range of infectious diseases by regulating the host-pathogen interactome. Like with immunomodulatory drugs, however, the use of biomarkers will inform the appropriate application and dosage stipulations of these drugs across infection types. Tempered by their contribution to antimicrobial resistance, such broad-acting drugs may constitute an ‘emergency treatment class’ for global health emergencies such as COVID-19, future respiratory pandemics, and potential bioterrorist attacks; a property reinforced by their extensive repositioning for pulmonary disorders and substantial affordability and international availability relative to antibody, vaccine, and plasma-based strategies. Ultimately, formal recognition of pan-pathogen antimicrobials can facilitate discovery of conserved infective and anti-infective mechanisms and pharmacophores, enabling the long-campaigned unification of the disparate fields of bacteriology, fungology, parasitology, and virology, while heralding a paradigm of antimicrobial development conceptually distinct from the antibiotic era of the 20th century.