This article discusses specificallyhow bacteria are now becoming resistant to antibiotics. This is largely due tothe fact that bacteria have been increasingly evolving, they have a highmutation and division rate, which gives them an advantage evolutionary wise.
Bacteria are also able to use horizontal gene transfer in order to becomeresistant to the antibiotics. It takes years to develop antibiotics and by thetime they are developed, bacteria have already evolved, potentially multipletimes. Antibiotics have been developed to bind to the fundamental proteins thatbacteria have to stop these mechanisms. The ways that bacteria have beenbecoming resistant are by preventing the binding of the antibiotic to theprotein, damaging or modifying the antibiotic and by prohibiting the antibioticto enter the cell.
This review looks into how the molecular and ecologicalfactors impact antibiotic resistance.The distribution of fitness effectsof beneficial mutations (DFBM) demonstrates the relationship between fitnessand mutations. It demonstrates that the DFBM is exponential making it possibleto estimate the fitness and mutation effects. When a low amount of antibioticsare used, low fitness mutations will have higher fitness than a wild type,which results in many mutations. When a high concentration of antibiotic isused, only a small amount of resistance occurs and this is currently how we areusing antibiotics is the medical field because it is able to kill off thebacteria more effectively. Horizontal gene transfer currently has no DFBM butit is still suggested that the fitness cost will still have impact on theresistance. In order to better understand howto predict the cost of resistance, the phenotype and phenotypic variations inbacteria has to be understood.
This cost of resistance can be determined by thesystems-based approach, which looks into the compensatory mutations and theeffects of resistance. The systems-based approach also looks into many levelsranging from proteins to cellular mechanisms. Some ways that compensatorymutations can occur are that the enzyme can be stored intragenic or extragenic,increasing the alternative path enzymes, decreasing the enzymes function andreducing the cost of carrying the plasmid. It is possible for a reversion ofresistance mutation but it occurs much less often and it dependent on theabsence of the drug.
Ecology also has a large influenceon the evolution of resistance. One technique in fighting bacteria is multidrugtreatment. Although this has been an efficient method in killing the bacteria,it has been shown that it may actually increase the resistance. If anantagonistic interaction occurs in the antibiotics, it will only slightlyresist the mutation. If a synergistic interaction occurs, it will largelyincrease the mutation.
In conclusion, the articlehighlighted how antibiotic resistance has occurred and the mechanisms thatbacteria have undergone in their evolution. The article examined how DFBM, costof resistance and ecology have all affected bacteria in their evolution towardsresistance. I think that the article did adecent job in describing how bacteria have become resistant to antibiotics.
Itproposed many problems that scientist are now facing concerning this problemand detailed the mechanisms in how bacteria is able to evolve, yet it offeredno resolution to this problem. Instead of suggesting areas of research orhighlighting successful research, it only focused on how the bacteria areevolving and how antibiotics are becoming less and less potent. This may bebecause there is not an abundant amount of research because this is a new andcurrent problem.