Proposal for rational antibacterial use in the diagnosis and treatment of dogs with chronic diarrhoea

Abstract

Chronic diarrhoea is a frequent complaint in canine practice and the diagnostic path is often characterised by numerous diagnostic tests and stepwise empirical treatments, often applied before gastrointestinal endoscopy/mucosal biopsies. These include dietary interventions (novel protein, hydrolysed protein diet), parasiticides and still, in many cases, antibacterials. Indiscriminate use of antibacterial drugs risks detrimental consequences for both the individual patient (antimicrobial resistance, long-term disruption of intestinal bacterial populations, potential worsening of gastrointestinal signs) and the general public. For that reason, in this Perspective essay we advocate use of antibacterials only after histopathologic evaluation of gastrointestinal biopsies or, for those cases in which endoscopy is not possible, after other therapeutic trials, such as diet/pre-probiotics or anti-inflammatory drugs have proven unsuccessful. They should be reserved, after appropriate dietary trials, for those canine chronic diarrhoeic patients with signs of true primary infection (i.e. signs of systemic inflammatory response syndrome or evidence of adherent-invasive bacteria) that justify antibacterial use.

Figure 1

Diagnostic algorithm for the diarrhoeic dog. This algorithm is suggested by our combined clinical experience, but different parts are also variably widely reported in literature, including (but not limited to): Jergens et al. 2003, Allenspach et al. 2007, Cerquetella et al. 2010, Washabau et al. 2010, Allenspach et al. 2016, Westermarck et al. Westermarck 2016, Erdmann & Heilmann 2017, Volkmann et al. 2017, Cerquetella et al. 2018, Heilmann et al. 2018. It is recommended to use (targeted, not broad spectrum) ABs in the chronic diarrhoeic dog (when there is no clinical evidence of a medical rationale for their immediate use), only at the end of the diagnostic protocol, once GI biopsies are performed, and with evidence of infectious causes. *In some cases more than one diet change may be needed, and for this reason duration of diet trial may vary. ^§Depending on the severity of clinical condition, these trials can be postponed going forward with the algorithm. FRD Food‐responsive diarrhoea, IBD Inflammatory bowel disease, SRD Immunosuppressive/steroid‐responsive diarrhoea