Resistance, Persistence and Microbiome
During evolution, bacteria have adapted successfully to their environment. Besides the formation of symbiotic partnerships, bacterial cells have faced naturally occurring antimicrobial substances for billions of years. Therefore, they have developed various mechanisms to resist molecules like antibiotics or antimicrobial peptides. We were able to show that these mechanisms namely resistance, persistence (including biofilm formation) do not interfere with the efficiency of Artilysin®s. Additionally, the natural microbiome is preserved and supports the innate healing process.
Resistance
Bacteria develop resistance to various antimicrobials. In order to analyse the ability of bacterial cells to adapt to Artilysin®s, external partners of LYSANDO AG have grown different bacterial species in the presence of sub-inhibitory concentrations of Artilysin®s and recorded the minimal inhibitory concentrations (MIC) over 30 cycles. In all experiments, no increase of the MIC was observed. In comparison, the MICs of classic antibiotics were determined in parallel as a positive control and increased up to 512-fold.
Persistence
Since antibiotics depend on an active bacterial metabolism, persistent cells cannot be addressed by classic antimicrobial therapy. These persistent cells survive higher concentrations of antibiotics and are therefore able to recolonise the site of infection after treatment has stopped. This is a crucial factor in the development of chronic or re-occurring infections.
| Pathogen | Persistent infection | |
|---|---|---|
| Chronic persistent infections | Helicobacter pylori | Gastritis |
| Acute persistent infections | Salmonella sp. | Chronic carrier with enhanced risk for carcinoma |
| Pseudomonas aeruginosa | Bronchiectasis, pneumonia (cystic fibrosis) | |
| Escherichia coli | Urinary tract infections | |
| Staphylococcus aureus | Bronchiectasis, pneumonia (cystic fibrosis), infections of prosthetic implants | |
| Haemophilus influenzae | Otitis media | |
| Pseudomonas aeruginosa Staphylococcus sp. |
Pyoderma, otitis externa |
In contrast to antibiotics, Artilysin®s are able to kill these persisters in a fast and efficient way. KU Leuven compared the efficacy of antibiotics and Artilysin®s on persisters. The persister cells were isolated by tobramycin and subsequently incubated with ciprofloxacin and Artilysin®, respectively. While ciprofloxacin was not able to kill persistent cells, Artilysin® Art-175 was able to significantly reduce the cell numbers. In combination with EDTA the persisters were completely eliminated.
Many persisters are present in so-called biofilms, where the cells are surrounded and protected by a complex matrix of exopolysaccharides. It has been shown that many antibiotics are not able to combat bacterial cells within the biofilm. Artilysin® Art-175 was tested on a 24h biofilm of Pseudomonas aeruginosa and was able to kill up to 99.9% of Pseudomonas aeruginosa cells.
Microbiome
Nowadays the crucial role of the microbiome for human health comes more and more into focus. New studies reveal that an imbalance of the natural bacterial flora is responsible for many lifestyle diseases like obesity and diabetes.
Due to their specific mode of action, Artilysin®s can distinguish between friend and foe. Microscopic motion pictures impressively show that Artilysin® specifically kills pathogenic Pseudomonas aeruginosa, whereas the commensal Staphylococcus epidermidis is unaffected.