Probiotics Against Antibiotic Resistance

As the challenge of anti-microbial resistance in healthcare continues to grow, it is estimated that this issue could be the potential cause of 10 million deaths per year by 2050¹. There is a pressure for the medical field to find a solution (and fast!), and an exciting new research study from MIT suggests a blend of probiotics and antibiotic drugs could be the key to fighting off certain types of stubborn bacteria: MRSA (Methicillin-resistant Staphylococcus aureus) and Pseudomonas aeruginosa.

What is antibiotic resistance?

Antibiotic resistance can be defined as the abilities of certain bacteria to resist the effects of antibiotics, which means that the antibiotics ultimately become ineffective at killing the resistant pathogenic organism. One well-publicised species of resistant bacteria is the hospital 'super-bug' known as MRSA (Methicillin-resistant Staphylococcus aureus). Various strains from this species of bacteria have developed resistance to all but the most potent of antibiotics. MRSA strains pose greater risks in hospitals because surgical procedures and lower immunity exposes patients to greater risk of catching MRSA infections, which can spread very quickly once contracted.

A second example of stubborn bacteria that is extremely resistant to most antibiotic treatment is Pseudomonas aeruginosa. This species of bacteria is commonly found on medical equipment such as catheters, due to its ability to thrive on moist or damp surfaces. Both of these 'super-bugs' are commonly found in wound infections and are extremely hard to treat. This is partially due to the biofilms (see Probiotics Learning Lab for more glossary terms) they produce – a sticky protective layer which surrounds the pathogenic organisms and prevents antibiotics from penetrating and killing the organisms.

The study

For the purposes of the study, US researchers from MIT focused on both of these strains of drug-resistant bacteria². Published in the journal ‘Advanced Materials’, the researchers discovered that by delivering a specific probiotic and antibiotic ‘killer combination’, both of the drug-resistant bacteria strains were eradicated completely.

The science

As healthcare professionals, you know that courses of antibiotics can negatively affect populations of beneficial bacteria at the same time as clearing up an infection by killing pathogens. This effect may lead to a microbial imbalance, or 'dysbiosis', which can result in numerous side effects such as antibiotic associated diarrhoea (AAD) or thrush. Therefore, taking probiotics – in particular, strains from species within the Lactobacillus genus – is thought to beneficial because certain strains have shown potential to re-balance the gut after antibiotic use.

Researchers put this knowledge to the ultimate test in this latest study, using three Lactobacillus strains found in the Canadian probiotic Bio-K+, alongside the antibiotic tobramycin, to target the super-bugs MRSA and P. aeruginosa. They found that because of the probiotic shell being encapsulated in a protective shell of alginate, the probiotic was protected from the tobramycin altogether.³

By stopping the antibiotic from hindering the probiotics, the probiotic strains were able to effectively inhibit the MRSA, whilst the tobramycin focused on eradicating P. aeruginosa. By having this protective casing encapsulating the probiotic bacteria, both the probiotic and the antibiotic were able to coexist and together wipe out the two harmful strains entirely. The authors hypothesised that this probiotic action was due to their ability to produce lactic acid and anti-microbial substances such as bacteriocins and biosurfactants, all of which inhibit pathogen growth. Biosurfactants in particular are able to break down biofilms produced by the pathogenic strains, which can enhance antibiotic action.

The outcome

So what do we do with this information going forward? The researchers believe these findings could be used to develop new types of bandages or other wound dressings embedded with antibiotics and alginate-encapsulated probiotics. Lead author Zhihao Li said:

"I think probiotics can be something that may revolutionise wound treatment in the future. With our work, we have expanded the application possibilities of probiotics."³

You may be interested to read more about probiotics and antibiotics here:

• Can probiotics prevent antibiotic resistance?
• Probiotics reduce risk of antibiotic-associated diarrhoea

References

1. de Kraker, M. E. A., et al. (2016) 'Will 10 Million People Die a Year due to Antimicrobial Resistance by 2050?' PLoS Medicine, 13(11): e1002184
2. Li, Z., et al. (2018) 'Biofilm-Inspired Encapsulation of Probiotics for the Treatment of Complex Infections.' Advanced Materials. Available at: https://doi.org/10.1002/adma.201803925
3. Trafton, A. (2018) 'Probiotics and antibiotics create a killer combination.' MIT News [Online]