Other factors affecting drug resistance

The ease with which different bacteria acquire resistance varies. For example, Staphylococcus aureus is notorious for its ability to acquire drug resistance due to the ease with which it can undergo transduction. On the other hand, the microorganism responsible for syphilis seems incapable of acquiring resistance and is still susceptible to the original drugs used against it. 

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The evolutionary fate of parasitic flat-worms lies intimately intertwined with the taxa they currently utilize, the taxa they can but have not yet utilized and the selective pressures driving speciation within and between parasites and their hosts. As with any other biological system, if time and conditions permit, natural selection will maintain diversity. Host switching, host speciation, vicariant events affecting parasites and/or hosts, an increase in host population size and dispersal and drug resistance are just some of the factors that will maintain or even promote the success of parasites and subsequently drive diversity in the hosts. 

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