If you cannot find Baytril (enrofloxacin), you might be able to use Cipro (ciprofloxacin) instead. Cipro is an extremely popular antibiotic and is used extensively worldwide. While it is marketed for use with people, it can be used with rabbits. However, Cipro has a much bigger issue with antibiotic resistance than Baytril---literally, some of the bacteria that Cipro was once hailed as the golden benchmark to destroy have developed resistance and Cipro can no longer control those infections at all.
If you are in desperate need of a wide spectrum antibiotic, several companies sell medications for fish, some of which are pharma grade. Doxy and TMP-SMX are both extensively used and those are very good antibiotics.
If you are in a situation where you cannot find Baytril but have access to a place that sells other meds, there are some other widespectrum options...
Doxycycline
Trimethoprim + sulfamethoxazole //OR// Trimethoprim + sulphadiazine
(obviously it is impossible to say definitively which antibiotics will work until the Vet performs a susceptibility test)
Should your rabbit be at super emergency level...i.e., he/she will likely die before an oral antibiotic kicks in, an IV antibiotic in the Cephalosporin family can be lifesaving.