Our war against bacteria is raging, and lately, antibiotics are doing little to help. The World Health Organisation (WHO) fears that very few antibiotics will serve as an army against pathogenic bacteria in the future, as drug resistant bacteria have emerged. Now, scientists all over the world are now looking for efficient alternatives to antibiotics, and think that the antimicrobial peptides could be one.The venom of a tiny, web-weaving spider, Lachesana tarabaevi is one of the sources for these peptides. In a new study, researchers from the Indian Institute of Technology, Delhi, have found that peptides derived from this spider’s venom is effective against Staphylococcus aureus, a bacteria that causes skin infections, and is resistant to many common antibiotics.
Lachesana tarabaevi belongs to a group of venomous spiders. If this spider bites us, it wouldn’t cause a colossal harm. However, its venom contains a protein known as latarcin, (Latarcin derived peptide), which the researchers have found to act against the menacing Staphylococcus aureus, infamously known as the ‘superbug’, as it is resistant to widely used antibiotics like methicillin, penicillin, oxacillin and amoxicillin.
“Our motivation behind this study was to establish the antimicrobial properties of a derivative of latarcin so as to develop a peptide-antibiotic against intracellular pathogens”, says Dr. Archana Chugh from Indian Institute of Technology, Delhi. The study, published in the European Journal of Pharmaceutical Sciences, compared the effectiveness of latarcin derivatives against Staphylococcus aureus resistant to methicillin.
For the study, the researchers used different derivatives of latarcin and fused it with nuclear localization sequence -- an amino acid sequence -- which would make it easy for latarcin to enter the bacterial cell. They then measured the lowest concentration of different latarcin derivatives required to prevent the visible growth of bacteria, and the time required to kill the bacteria. They used HeLa cells, a human cell line, for the study.
The results showed that one of the derivatives had the highest efficacy against Staphylococcus aureus resistant to methicillin, even with very small concentrations. It was also found that two of latarcin derivatives could kill 99% of the bacteria and could cause significant cell damage to 92.6% of the bacteria within five minutes. In addition, these derivatives were found to be non-toxic to the mammalian (host) cells, as well as the non-infected cells.
“The major implication of this study would be a viable, potent attempt to address the current global challenge of antibiotic resistance”, says Dr. Chugh, talking about the study. “With this, antibiotic resistant strains of bacteria can be targeted and eliminated. The work can be extrapolated to various other serious antibiotic resistant microbes such as Mycobacterium and Staphylococcus aureus resistant to vancomycin, another antibiotic”, she adds.
The researchers believe that if further worked upon, latarcin peptides might even substitute antibiotics in the near future. Her team is currently testing the efficiency of these peptides on other pathogenic strains of bacteria.