Medical Chronicle recently hosted a webinar on the collateral damage and the potential role of probiotics. This webinar was sponsored by Austell and presented by clinical microbiologist Dr Jennifer Coetzee.
To watch a replay of this webinar and still earn a CPD point, go to: https://event.webinarjam.com/replay/837/10wo0up78t8mwcw89h5xwz. Email john.woodford@newmedia.co.za to let him know to allocate your point/ request an attendance certificate for those who don’t fall under the HPCSA.
The following article is based on Dr Coetzee’s informative presentation. Antibiotics are one of the most significant discoveries in the pharmaceutical industry. Alexander Fleming discovered penicillin in 1927, which was later purified by Dr Howard Florey and Dr Ernest Chain. The first patient treated with penicillin was Albert Alexander in 1941, who unfortunately died when the supply ran out. Antibiotics have since revolutionised medical practice, enabling major surgeries, cancer chemotherapy, organ transplantation, and neonatal intensive care.
The problem with antibiotics
Despite their benefits, antibiotics are not without drawbacks. They are often broad-spectrum and non-specific, leading to side effects in approximately 20% of patients. The term 'collateral damage' describes the unintended consequences of antibiotic use, including antibiotic resistance, Clostridium difficile infection, and disturbances in the microbiome.
Collateral damage and antibiotic resistance
Antibiotic resistance is a significant community-wide issue, while individual patients may suffer from infections with ESBL- and MRSA organisms. Studies have shown that bacteria exposed to antibiotics can develop resistance over time, complicating treatment efforts.
The concept of colonisation resistance
The gut microbiome plays a crucial role in colonisation resistance, where normal flora prevent pathogenic bacteria from establishing themselves. This involves nutrient competition, production of antagonistic peptides, and modulation of the host immune system. Antibiotics can disrupt this balance, leading to adverse effects.
The human microbiome
The human microbiome consists of approximately 1000 species and three million microbial genes, compared to 23 000 human genes. Each body site hosts a unique microbial community. However, only 0.4% of these species can be characterised through culture techniques, highlighting the complexity of the microbiome.
Factors influencing the microbiome
Several factors influence the microbiome, including mode of birth, diet, exposure to bacteria, and antibiotics. Modern genomic techniques allow for the classification and comparison of bacterial communities, providing insights into the microbiome's role in health and disease.
Clostridium difficile infection (CDI)
Clostridium difficile, an anaerobic, Gram-positive, spore-forming bacillus, releases enterotoxins TcdA and TcdB, causing colitis in susceptible individuals. CDI can range from asymptomatic colonisation to severe diarrhoea and death. Risk factors include advanced age, hospitalisation, gastrointestinal surgery, and exposure to certain antibiotics and antineoplastic agents.
Diagnosis and management of CDI
Early recognition of CDI is essential. Diagnosis involves a high index of clinical suspicion and laboratory tests, including tissue culture cytotoxicity assays, enzyme-linked immunoassays, and PCR. Management includes stopping the offending antibiotic and administering vancomycin or fidaxomicin as
first-line therapy.
Potential role of probiotics
Probiotics are live microorganisms that confer health benefits when administered in adequate amounts. They include Lactobacilli, Saccharomyces boulardii, and some E. coli and Bacillus species. Probiotics can potentially reduce the collateral damage of antibiotics by preventing antibiotic-associated diarrhoea (AAD) and reducing the need for antibiotics.
Prevention of antibiotic-associated diarrhoea
Probiotics may restore intestinal microbial balance and have immunomodulatory effects. A pilot study showed that patients treated with Lactobacillus reuteri had a significantly lower frequency of diarrhoea compared to placebo.
Reducing the need for antibiotics
A randomised, double-blind, placebo-controlled trial in preschool children found that L. reuteri significantly reduced the frequency and duration of diarrhoea and respiratory tract infections, leading to fewer doctor visits and antibiotic use.
Caution with probiotics
While probiotics offer benefits, caution is necessary. A case study of a 23-year-old male with osteosarcoma revealed persistent bacteremia with Bacillus clausii, a probiotic organism. This highlights the need for careful use, especially in immunocompromised patients.
Conclusion
Antibiotics have transformed medical practice, but their use comes with risks. Probiotics offer a promising approach to mitigating some of these risks, but their use must be carefully managed. Ongoing research and clinical vigilance are essential to optimise patient outcomes.
