Loratadine's antibiotic adjuvant effects in MRSA 43300

Methicillin-resistant Staphylococcus aureus (MRSA) is a major threat to human health. Rather than depend on creating new antibiotics (to which bacteria will eventually become resistant), we are employing antibiotic adjuvants that potentiate existing antibiotics. Based on our previous work, loratadine, the FDA-approvide antihistamine, effectively potentiates cell-wall active antibiotics in multiple strains of MRSA. Furthermore, loratadine and oxacillin helped disrupt preformed biofilms and stop them from initially forming in vitro. To gain biological insight into how this potentiation and biofilm inhibition occurs, we used RNA-seq on treated MRSA 43300 cultures to examine antibiotic adjuvant affects transcritome-wide. Differential gene expression was examined between MRSA cultures either untreated, treated with oxacillin only, treated with an antibiotic adjuvant (loratadine), or cotreated with oxacillin and loratadine. Each of the four treatments was performed with biological triplicates.