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Do probiotics and prebiotics reduce infections after surgery?

Skin protects us from pathogens, making surgery is risky endeavor when it comes to infection. This meta-analysis looked at all the existing trials on probiotics (with or without prebiotics) for infection reduction

Study under review: Effects of perioperative supplementation with pro-/synbiotics on clinical outcomes in surgical patients: A meta-analysis with trial sequential analysis of randomized controlled trials


Infections after surgical procedures plague modern healthcare. Globally, the annual number of major surgical procedures taking place is estimated at more than 234 million[1]. More than 5% of patients[2] undergoing these surgeries will develop an infection at the site of the surgery. Antibiotics are given before, during, and after surgery to reduce the risk of these infections. However, the use of antibiotics carries its own risks, and research is focusing on new methods to reduce surgical infections. The use of probiotics and synbiotics is one treatment being investigated.

Surgery can have immunosuppressive effects, as shown in Figure 1, making infection a serious concern. When a wound infection occurs after a surgery, the infection is known as surgical site infection and is often caused by microorganisms from the patient's own body contaminating the incision during the surgery. Pneumonia and urinary tract infections are other common causes of disease after surgery. These infections increase[3] the use of antibiotics and prolong the time spent in intensive care units, greatly increasing medical costs.

Figure 1: Immunosuppressive effects of surgery

Reference: Hogan et al. Surgeon. 2011 Feb.

The gut is intimately linked to the initiation of the systemic inflammatory response following surgery. The human intestine is inhabited by a complex microbiota composed of bacteria, yeast, and viruses. This microbiota carries out a variety of beneficial nutritional and biochemical functions. Surgical trauma[4] and antibiotic treatment[5] can disrupt gut microbiota function, in turn disrupting human metabolism and gut immune function. Reducing the disruption of the gut microbiome is a potential way to reduce complications after surgery. Therapies attempting to improve gut health have so far included probiotics, prebiotics, and synbiotic treatment.

Probiotics are living microorganisms[6] that may provide health benefits when consumed in sufficient amounts. The most commonly used probiotics include bacteria such as bifidobacteria and lactobacilli, and the yeast Saccharomyces boulardii. Prebiotics are types of dietary fiber[7] that are fermented by bacteria in the colon. They benefit human health by selectively feeding the growth and promoting the function of beneficial intestinal microorganisms. Prebiotics are often used in the form of purified prebiotic fibres such as fructooligosaccharides, inulin, resistant starch, pectin, and beta-glucans.

The term synbiotics[8] is used to describe the combination of probiotics with prebiotics. Synbiotics aim to improve the survival and growth of probiotics in the gut by supplying prebiotic fiber as a food source encouraging the growth of probiotics while also feeding other beneficial resident bacteria in the colon. This synergistic effect of synbiotics may provide additional benefits over probiotics alone, although there is a lack of clinical data demonstrating this.

Randomised controlled trials (RCTs) testing probiotic or synbiotic therapies suggest these may have specific benefits after surgery. However, some RCTs have produced conflicting results. And the use of such treatments in surgery remain controversial, due to potential infections caused by the probiotic, unknown side-effects, and uncertainty over their effectiveness. This is partly due to a lack of evidence from large clinical trials. Several previous[9] reviews[10] investigating this subject have not been systematic, or were focused on particular types of surgery such as colorectal cancer[11], abdominal surgery[12], or liver transplants[13]. The current study reviewed the currently published RCTs available involving all types of surgery and then carried out a meta-analysis to quantitatively summarize the findings.

Infections resulting from surgery are a major problem in modern medicine. Probiotics and synbiotics have been proposed as a new way to reduce infections and disease after surgery. This study aimed to combine the results of all the RCTs currently available to identify and summarise the latest and most convincing evidence for their effectiveness.

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