Antibiotics are a crucial part of the medical toolbox, but their clinical benefit for patients must be balanced against possible adverse drug reactions and increased risk of Clostridium difficile infection (CDI). Studies indicate between one quarter and one half of all antibiotics prescribed in US acute care hospitals are either unnecessary or inappropriate. Widespread antibiotic misuse has also contributed to the problem of antimicrobial resistance (AMR), a serious public health threat that continues to grow. AMR occurs when microorganisms change in ways that render antibiotics ineffective at killing them or controlling their growth. An estimated 23,000 deaths in the US annually are attributable to infection with antibiotic-resistant organisms; according to the World Health Organization, “AMR is an increasingly serious threat to global public health that requires action across all government sectors and society”.


These points have led to the worldwide emergence of hospital-based antibiotic stewardship programs (ASPs)—coordinated strategies to limit inappropriate and excessive antibiotic use. In addition to reducing antibiotic resistance, such programs aim to improve patient health outcomes (through increased infection cure rates, reduced treatment failures, and correct therapeutic and prophylactic prescriptions) while decreasing unnecessary costs. In 2014, the CDC recommended all acute care hospitals implement ASPs, and subsequently outlined the core elements of successful programs.


Members of the scientific community have raised the idea of whether, given current scientific evidence, probiotics can be a tool employed in ASPs and other initiatives for reducing inappropriate use of antibiotics. In practice, the drugs are often used improperly to address common infections caused by viruses, leading some experts wonder whether probiotics may be used prophylactically to reduce the occurrence of infections in the first place, or render them less severe.


“Prevention is always preferred to treatment,” says Mary Ellen Sanders, Executive Science Officer for the International Scientific Association for Probiotics and Prebiotics (ISAPP). “If we prevent infections, antibiotics can be fully avoided.”


At the 2016 ISAPP meeting in Turku, Finland, a working group, led by Dan Merenstein of Georgetown University (USA) and Irene Lenoir-Wijnkoop of University of Utrecht (the Netherlands) and Danone Research, laid out the strength of evidence to support probiotics in reducing the incidence and severity of upper respiratory tract infections (URTIs)—the common cold.


A 2015 Cochrane meta-analysis of 12 studies indicated evidence is accumulating, but not definitive, for probiotics in improving outcomes related to URTIs: probiotic use resulted in 11 fewer people out of 100 developing an URTI, and reduced the duration of a URTI by around 2 days. Yet it was clear that the use of probiotics was associated with lower antibiotic prescription rates for acute URTIs.


Health-economic analyses of specific countries, published in 2015 and 2016, showed that widespread probiotic consumption could potentially save hundreds of thousands of antibiotic prescriptions per year (between 291,000 and 473,000 in France; between 52,000 and 84,000 in Canada) and beget significant healthcare cost savings through their impact on URTIs.


Missing from the literature is a systematic review of randomized, controlled trials to examine the overall impact of probiotics on inappropriate antibiotic prescriptions within the context of common acute infections. ISAPP members and collaborators have now initiated such a review, addressing the question: Is the use of antibiotics reduced when people are given probiotics to prevent or treat common acute infections?


“This research question was chosen because studies on common acute infections are the ones that report on antibiotic prescription use,” says Sanders, an author on the systematic review protocol.


The protocol has been registered with PROSPERO (registration number CRD42016052694) and is scheduled to be published within the next year.