ALT Mutation of a glycosyltransferase or genetic recombination can cause h18:0 resistance.

ALT Experimental evolution of S. pneumoniae in response to levofloxacin during infection. Schematic diagram of in vivo passaging workflow. Three mice, representing three lineages, were intranasally infected with TIGR4 and, after 6 h of infection, mice were treated with levofloxacin. Twelve hours after levofloxacin treatment, bacteria were collected from lungs of infected mice and recovered on media plates following overnight incubation. Frozen aliquots from each passage served as the inoculum to infect the subsequent group of mice for each lineage. Created with BioRender.com (A). After each passage under levofloxacin pressure, bacterial burden in the lungs was enumerated. Dosage of levofloxacin ranged from 25 to 200 mg/kg as indicated. Each data point represents an individual mouse and bars represent median with range (B).