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. Some sites of infection have predictable common bacterial species, for example Staphylococci in canine pyoderma.3 Knowledge of the site of infection may also suggest whether bacteria are likely to be aerobic or anaerobic, for example abscesses are likely to involve obligate and facultative anaerobes.3


Suggested antimicrobials for gastrointestinal infections*




Amoxicillin-clavulanic acid or 1st generation cephalosporin83 for diarrhoea with complications

Enrofloxacin or erythromycin for Campylobacter83

Amoxicillin-clavulanic acid 14 or a 1st generation cephalosporin with metronidazole83 if there is bleeding or a risk of intestinal bacterial translocation. Fluoroquinolones or aminoglycosides for Gram-negative cover.83

Enrofloxacin,14,82 metronidazole82 and amoxicillin82 for histiocytic ulcerative colitis


Antimicrobials are not indicated for acute, uncomplicated vomiting or diarrhoea unless cytology and/or culture results are positive.83


Common bacterial pathogens14

Salmonella spp.

Campylobacter spp.

Clostridia spp.

Escherichia coli


*Suggested antimicrobials are based on references from scientific literature and may not necessarily reflect UK market authorisations for the relevant species or condition. Veterinary surgeons are advised to carefully check the Summary of Product Characteristics (SPC) before prescribing a product.

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.