Baytril and Mycoplasma in Mice

Author: Kallan

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This article was written by a qualified vet regarding article regarding baytril dosages and mycoplasma in Mice. It is applicable to UK only.

Read and take heed!

I find a lot of opinions on the internet stating, 'Baytril is rubbish', or 'the dose needs to be higher', or, 'the vet is stupid and knows nothing and Baytril is useless'.

Baytril is Enrofloxacin, a reserve drug in human medicine for hard-to-treat cases. It is NOT a first-line drug. Ideally sniffly mice would get a penicillin-family drug first before getting Baytril. But because Baytril is the only licensed antibiotic, BY LAW we have to prescribe it first, before trying anything else. This is why all small furries will get Baytril. We do not like using enrofloxacin first, because if resistance develops to it we have very little different antibiotics better than it.

We are lucky in mice that the toxicity level of Baytril is very high. For rodents, the maximum level with little effect is something ridiculous - 40mg/kg. If you give that to a cat, you've just blinded it. In a rabbit, you've given it seizures.

Because mice are so tiny, you either put Baytril in the drinking water, or you give oral drops of varying concentrations. Depending on the dilution, one drop per mouse could be 2 times the recommended dose to 20 times the recommended dose. This is why you should not tell people to 'give more, that's clearly not enough' - we have given a certain prescription for a reason.

Second point, Mycoplasma pulmonis is the mycoplasmal bacteria most often associated with respiratory disease in the mouse. It is a commensal, i.e almost all mice carry it. It causes a problem when the mouse is stressed - this could be a new home, dirty cage, hot environment, other illness, new cagemates causing stress, etc.

An upper respiratory infection may be shifted if antibiotics are started early enough, but the underlying problem needs to be addressed too. Sometimes the underlying issue is never found.

Once myco sets up an infection in the lungs, it is very, very difficult to treat, it's the same in any species. In this case the mouse may need to be on antibiotics for the rest of its life (not ideal for the world but better for the mouse). But sometimes the antibiotics are just not enough, the infection is set in too deep.