Other bacteria


Knowledge of the bacterial species present when dealing with an infectious condition will be very helpful in selecting an appropriate antimicrobial and therefore culture and sensitivity testing is often indicated. If this information is not available, a combination of cytology and a knowledge of which pathogens are likely for a given situation may help in selecting an appropriate antimicrobial. Cytology will allow classification of the bacteria present by Gram-staining and morphology, which will narrow down the possible species. Knowledge of the site of infection may suggest whether bacteria are likely to be aerobic or anaerobic, for example cases of pyothorax and abscesses are likely to involve obligate and facultative anaerobes.3


Type of organism

Other bacteria


Possible bacterial pathogens4

Chlamydophila spp. – Gram-negative intracellular

Actinomyces spp. – Gram-positive branching filaments. Facultative anaerobe.

Nocardia spp. – Gram-positive branching filaments

Mycoplasma spp. – Gram-negative, pleomorphic. Can be facultatively anaerobic.


Useful antimicrobials5,6


Clindamycin for obligate anaerobes


Trimethoprim/Sulphonamide for Nocardia spp.

Fluoroquinolones for Mycoplasma spp.


Key: Aerobic Anaerobic




Disclaimer:  Indications and doses may vary between products.  The antimicrobials listed may constitute an off licence use of the product and as such should only be used according to the ‘Cascade’, further details of which are available on the RCVS, VMD and NOAH websites.  Veterinary surgeons are advised to carefully check the Summary of Product Characteristics (SPC) before prescribing a product and obtain informed owner consent where required.