Probiotics in general practice: why the strain matters, antibiotic timing, IBS, H. pylori, gastro, BV and children's teeth

Speaker

Charlotte, integrative general practitioner. Introduced by the chair as working in menopause care, a medical adviser to a company, founder of an integrative medicine education platform, and director and principal GP at an integrative medical clinic in the Illawarra, New South Wales (described as the first of its kind there). The organisation names were badly garbled by the speech recogniser, so they are not repeated here. Her surname was not captured. She jokes that she is "not the Charlotte" from an earlier case in the day's programme.

Commercial context

Charlotte says she has been "told I'm allowed" to give brand-specific recommendations at the end, and that these are brands she uses every day. The brand slide was in the delegates' handbook. The brand names in the transcript are unclear, so none are listed on this page. Treat the session as likely to have had industry involvement and check products yourself.

Session context

Otter title Probiotics in Medical Practice · id y5Fx5TquWhs2JHohmxP7DvZS8Ro · ~24 min. Speaker 1 is the chair; Speaker 3 only appears as a few stray words picked up by the recorder.

Key messages for GPs

• A probiotic must give a proven health benefit at an adequate dose. Without that, as a microbiologist told Charlotte, "they are just simply called bacteria".
• The strain is what counts. Evidence applies to a specific strain, at a specific dose, for a specific condition. Different strains of the same species can behave differently.
• Antibiotics: start the probiotic within two days of the antibiotic, keep it going for the whole course and for two weeks after, and separate the doses by two to three hours. The old "antibiotics first, probiotics afterwards" advice was described as outdated.
• Charlotte said the RACGP has recommended probiotics since 2019 to prevent antibiotic-associated diarrhoea in people at higher risk, and that most of our patients fit at least one risk factor.
• Guideline-backed areas she highlighted: antibiotic-associated diarrhoea and acute gastroenteritis in children (ESPGHAN and the World Gastroenterology Organisation, as spoken), with trial support for IBS, H. pylori treatment, BV, recurrent vulvovaginal candidiasis and caries.
• Patients are asking. In a 2021 survey, women not using probiotics said a health professional's advice would be what changed their minds. GPs are well placed to give evidence-based answers.

What a probiotic is (and is not)

The human microbiota is a large, complex and changing community of microorganisms living in and on us. The gut community is the largest and most important, followed by the oral, skin, respiratory and vaginal communities. Their make-up varies by body site and across life stages, and is shaped by environment, diet and illness.

A healthy microbiota supports gut processes, metabolism and immune regulation. Dysbiosis (imbalance or disruption) is linked with a range of conditions. The hopeful part, Charlotte said, is that changing the microbiota can help prevent, support and manage some of them.

Why the topic has changed so much: rapid growth in clinical trials over two decades, rising patient interest, and a crowded market. Charlotte said there are something like over 300 probiotic products listed on the Australian Register of Therapeutic Goods (her figure).

Strain matters most

Probiotics are classified by family, genus, species and strain. Clinical trials, and therefore the benefits you can quote to patients, are at the strain level.

How they work

• Promote microbial balance, crowding out pathogens.
• Strengthen the gut lining (epithelial function and barrier).
• Modulate the microbiota and gut-brain axis. "There's a reason why our gut is called the second brain."
• Directly modulate the immune system.

Irritable bowel syndrome

IBS affects up to 1 in 10 Australian adults, with abdominal pain, gas, bloating, and changes in stool frequency and form (constipation and/or diarrhoea). It also takes a toll on mental health and quality of life.

Causes are many and interacting: central factors, diet, and gut factors such as dysmotility, increased mucosal permeability, altered immune function and an altered gut microbiota, which has been observed in people with IBS.

Usual care (diet changes and symptom-relieving medicines) often disappoints, with poor response, side effects and people stopping treatment. Charlotte presented probiotics as an extra tool, backed by randomised placebo-controlled trials showing improvement in global symptoms, pain, bloating and quality of life.

• Strains named (species level only in the transcript): L. reuteri, L. plantarum and a Bifidobacterium strain.
• Results described: significant reductions in symptom frequency and severity, better quality-of-life scores, and less anxiety, over four to eight weeks.
• Trial sizes mentioned: from about 140 to over 400 participants.
• Practical advice: for IBS, trial a probiotic for at least six weeks before judging it.

Antibiotic-associated diarrhoea and timing

Antibiotics reduce gut species diversity and upset microbial balance. That can lead to antibiotic-associated diarrhoea, Clostridioides difficile infection (hard to clear once established), antibiotic resistance and, Charlotte said, possible longer-term metabolic effects such as obesity.

• Charlotte stated that the RACGP has recommended probiotics since 2019 to prevent antibiotic-associated diarrhoea in higher-risk patients. Looking at the risk factor list, she estimated that around 90% of our patients would fit at least one (her estimate).
• Pooled evidence as quoted: adults were 38% less likely to get antibiotic-associated diarrhoea with a probiotic; in children the risk was more than halved.
• L. rhamnosus GG and Saccharomyces boulardii are recommended by ESPGHAN and the World Gastroenterology Organisation for prevention, at the higher doses studied, started with the antibiotic and continued for its duration.

Helicobacter pylori

Standard eradication uses a proton pump inhibitor plus two antibiotics, which brings gut side effects, microbiota disruption and resistance concerns. Charlotte said adding probiotics can:

• Cut treatment-related diarrhoea by about 45% (as quoted).
• Improve eradication rates compared with antibiotics alone.
• Two L. reuteri strains gave significant reductions in gut symptoms and gastritis from baseline at eight weeks, with less abdominal pain and distension reported after just two weeks.

Acute gastroenteritis in children

Gastroenteritis is a major burden in children under five. Figures as spoken: about 1.6 episodes per child per year and around 250,000 GP visits a year in Australia (a "14%" figure was also spoken but its context was unclear). It is a big dysbiosis event that disrupts gut diversity, metabolism and the intestinal barrier through an inflammatory response.

Dehydration remains the main concern and oral rehydration solution is the treatment, but ORS does not shorten the diarrhoea. ESPGHAN and the World Gastroenterology Organisation (as spoken) recommend probiotics as an adjunct to ORS to reduce symptoms and hospital stay.

• Strains named: L. reuteri, L. rhamnosus (GG), S. boulardii, and a combination of L. rhamnosus with L. reuteri.
• Duration: at least five to seven days.
• Outcomes: shorter duration of diarrhoea and shorter hospitalisation.

Vaginal health: BV and recurrent thrush

The vaginal microbiota is mainly Lactobacillus species in the reproductive years and changes across life. Factors that shift it include genetics, ethnicity, pregnancy, perimenopause and menopause, diet, hygiene and sexual practices, and stress (one further factor was garbled in the transcript).

Bacterial vaginosis

• Up to 50% of women will have an episode of BV (as spoken).
• The hallmark is loss of Lactobacillus, allowing overgrowth of anaerobes such as Gardnerella, which form biofilms on the vaginal lining and undermine its normal defences.
• Standard care is oral or vaginal antibiotics, yet up to 80% recur within 12 months.
• Meta-analyses support probiotics alone or with antibiotics. Strain-specific evidence for L. rhamnosus and L. reuteri: over 80% cure at four weeks versus 40 to 50% with antibiotics alone (as quoted).

Recurrent vulvovaginal candidiasis

• In a study of women with up to four recurrences a year, 70% were recurrence-free after seven months on the probiotic (as quoted).
• Most products studied are oral; evidence for vaginal administration is emerging, and local delivery makes sense.

Oral health and caries

The mouth holds the body's second-largest microbial community, living in biofilms on teeth, gum crevices, cheek and gum surfaces and the tongue, and linked to the gut through an oral-gut axis. Most are beneficial, but some, such as Streptococcus mutans, cause disease. Oral health links to systemic health, including an association with cardiovascular disease.

• Oral dysbiosis shows up as halitosis, caries, gingivitis and periodontitis. Risk factors: high sugar intake, poor oral hygiene, tobacco and alcohol.
• Tooth decay is the most common oral disease in Australian children: 42% of 5 to 10 year olds, and 24% in permanent teeth (figures as spoken).
• Mechanism: the balance tips from alkali-producing to acid-producing bacteria, which build biofilms and an acidic environment that demineralises enamel.
• Evidence quoted: lozenges with two L. reuteri strains gave 43% fewer children carrying S. mutans (a study of 40 children); Streptococcus salivarius gave about a 60% reduction in S. mutans.
• How to use: brush teeth, then suck a lozenge at bedtime and let it work overnight.

GP clinic checklist

1. When a patient asks "which probiotic?", answer with the condition first, then a product whose label shows the studied strain.
2. With antibiotics in higher-risk patients: start within two days, separate by two to three hours, continue two weeks after.
3. IBS: trial for at least six weeks, then review.
4. H. pylori: consider a probiotic alongside eradication therapy to reduce diarrhoea and support eradication.
5. Child gastroenteritis: ORS first; a guideline-listed probiotic for five to seven days as an adjunct.
6. Recurrent BV or thrush: discuss a strain-matched probiotic with standard treatment.
7. Caries risk in children: bedtime lozenge after brushing, alongside sugar and hygiene advice.
8. Choose an age-appropriate form: drops, chewables, powders, lozenges, tablets or capsules.

Transcript caveats

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