Are antibiotics actually indicated if there is concern over potential bacterial translocation?
Dysbiosis, immunosuppression or damage to the gastrointestinal epithelium may contribute to the translocation of viable bacteria from the lumen of the gut to extra-intestinal sites (Brenchley and Douek, 2012). These bacteria may originate from the commensal population or may have been introduced into the gut via ingestion. If the bacteria reach the blood, they could cause disseminated infections or even life-threatening septicaemia or sepsis. Therefore, antibiotics may be given to individuals that are at a higher risk of translocation of potentially pathogenic bacteria, such as animals with acute haemorrhagic diarrhoea where the gastrointestinal barrier may be compromised (Armstrong, 2013). Further recommendations to try to limit bacterial translocation include restoring intestinal perfusion, commencing early feeding, maintaining a normal gastrointestinal microbiota and supporting the gut barrier function (Krentz and Allen, 2017).
However, it has also been suggested that antibiotic use may not be the solution in the face of potential bacterial translocation and could even worsen the situation. Research in human medicine has reported that antibiotic use can induce translocation of commensal bacteria, increase inflammatory responses and increase the release of Shiga-like toxin by E. coli O157 (Panos et al., 2006; Knoop et al., 2016). It has been proposed that anaerobic bacteria may play a role in preventing bacterial translocation and that the use of antibiotics which selectively kill anaerobes may therefore increase risk of bacterial translocation; mice that received metronidazole experienced increased dissemination of intestinal bacteria to their mesenteric lymph nodes compared to control animals (Wells et al., 1987).
A prospective study looking at bacteraemia in canine patients with acute haemorrhagic diarrhoea syndrome (AHDS) found no significant difference in the incidence of bacteraemia between dogs with AHDS and control dogs. Nor were there significant differences in the clinical signs, laboratory parameters, duration of hospitalisation or mortality between blood culture positive and blood culture negative affected dogs (Unterer et al., 2015). The use of antibiotics (amoxicillin/clavulanic acid) in dogs with AHDS and a positive blood culture showed no benefit; however, dogs with potential signs of sepsis were excluded from this study (Unterer et al., 2011). Another study found that dogs with AHDS and a left shift neutrophilia recovered well in the absence of antimicrobial therapy (Mortier et al., 2015). By studying cultures of mesenteric lymph nodes, bacterial translocation was even demonstrated in 52 percent of healthy dogs undergoing routine ovariohysterectomy (Dahlinger et al., 1997). All of these studies demonstrate that bacteraemia is not necessarily associated with clinical disease, questioning the use of antibiotics even if bacteraemia may be present.
The term “bacteraemia” refers to the presence of bacteria within the bloodstream and is confirmed by repeat isolation of a pathogen from culture of the patient’s blood (Nostrandt, 1990). Whilst bacteraemia is not necessarily associated with clinical disease, the potential for development of septicaemia or sepsis is a valid concern. Septicaemia and sepsis are respectively defined as “systemic disease caused by the spread of microorganisms and their toxins via the circulating blood” and “life-threatening organ dysfunction caused by a dysregulated host response to infection” (Odeh, 1996; Singer et al., 2016). If septicaemia or sepsis is even suspected, due to deteriorating systemic clinical signs, haematological changes and/or positive blood culture, then appropriate parenteral antibiotics should be started immediately.
Despite the lack of studies demonstrating that haemorrhagic diarrhoea is associated with an increased risk of bacterial translocation or sepsis, some clinicians will still elect to use antibiotics in patients with acute haemorrhagic diarrhoea (Armstrong, 2013). This is likely due to the potential severity of septicaemia should it occur, and the difficulty involved in confirming bacterial infection as the cause of diarrhoea.
Antibiotic use can be detrimental at a patient and/or population level
Antibiotics used to treat a specific infection can simultaneously affect bacterial species within the normal gastrointestinal microbiota, resulting in a microbial imbalance or “dysbiosis”. The normal microbiota balance will usually recover once the antibiotics are stopped; however, a prolonged dysbiosis may occur in some individuals which could result in persistent signs of gastrointestinal upset (Canine Microbiota Dysbiosis Index, 2020). Administration of metronidazole to healthy dogs has been reported to decrease the numbers of specific groups of bacteria that are thought to be important for gut health; four weeks after cessation of a two-week metronidazole course, some of these changes were still present (Olson et al., 2015). Ciprofloxacin has also been shown to reduce taxonomic richness and diversity of gut bacterial populations in people (Dethlefsen et al., 2008). An individual’s microbiota appears to be intimately involved in many normal body functions, therefore its disruption through use of antibiotics should always be considered and requires reasonable justification.
What Can You Give A Dog For Upset Stomach From Antibiotics?
Here’s what to do to help protect your dog from antibiotic damage … and restore his gut health after antibiotics.
Diarrhea in Dogs: How To Quickly Treat At Home
Your dog has trillions of organisms in his body. Bacteria, fungi, archaea, and eukaryotes make up the canine microbiome … and they outnumber the cells in his body 10:1. They’re everywhere … in your dog’s gut, spread all over his skin, lungs and urinary tract and even in places like his nailbeds,.
The canine microbiome helps protect against disease, maintain healthy digestion and regulate hormones. So, a healthy microbiome = a healthy dog.
But what happens when you add the side effects of antibiotics in dogs into the equation? What can you do to prevent and manage dog diarrhea after antibiotics?
Dysbiosis is when the canine microbiome is out of balance (1). There’s tons of evidence linking an imbalanced microbiome to a variety of diseases. Here are just a few of them …
Unfortunately, veterinarians often prescribe antibiotics for just about any illness in your dog. And that leads to long term gut damage that weakens your dog’s ability to resist disease.
Antibiotics have the same effect on the microbiome as bulldozers in a rainforest. They destroy everything in their path.
A few organisms in the microbiome are resistant to some common antibiotics. Many are not. This means that antibiotics kill the beneficial organisms as well as the bad ones … and that leads to dysbiosis and exposes your dog to some of the diseases listed earlier.
And it isn’t just antibiotics that can harm these beneficial organisms. Your dog’s microbiome is also sensitive to many other drugs and foods. One example is a proton pump inhibitor drug called omeprazole. This drug helps suppress stomach acid, in both humans and dogs. While further studies are needed, this drug has already been linked to dysbiosis (6).