The emergence of superbugs is leading to a global health crisis of epic proportions. Ms Zsuzsanna Jakab, WHO Regional Director for Europe, said: “Since their discovery over 70 years ago, antibiotics have kept most of us alive by overcoming bacterial infections that could otherwise have been fatal. The use of antibiotics – and vaccines – has lengthened our life-spans by 20 years on average.” Now these miracle drugs are becoming obsolete due to widespread drug resistance. Diseases that we have been able to manage for the past 70 years are resurfacing with a vengeance.
‘Superbugs’ are common bacterial pathogens that have evolved to cause severe and antibiotic resistant infections. Bacteria have naturally occurring mutations during DNA replication. These mutations will often be detrimental to the organism; however, occasionally the mutation may prove to be advantageous. For example, a mutation may alter the target protein of an antibiotic rendering it resistant to that antibiotic. When this occurs in a pathogen that is infecting a host subjected to that antibiotic, the resistant organism may now flourish in the absence of nutritional competitors. Other mutations may contribute to the organism producing factors that cause a more serious infection.
Hospitals are a notorious site for the emergence of superbugs for a number of reasons. Hospitals contain susceptible and compromised hosts in close proximity. Patients admitted to the hospital may carry drug resistant or highly virulent strains of bacteria. There are antimicrobial agents being administered to the patients and used for sterilizing equipment and surfaces. These are the agents that place evolutionary pressure on the bacteria that can lead to the development of resistant, hardy strains of the pathogen.
Incomplete antibiotic administration is also a major contributor to resistance as it fails to completely eradicate a normally susceptible strain. Low sub lethal levels of antibiotic give the pathogen more time to adapt by allowing for cell division i.e. more cycles of DNA replication and thus a higher chance of acquiring resistance. Although, this poor practice is found in developed nations, it is particularly prevalent in developing nations where inferior antibiotics are available with little to no guidance on their administration.
Finally, many bacteria have developed mechanisms to transfer antibiotic resistance genes to neighboring bacteria through a process called conjugation. They effectively send the DNA coding for resistance over to their neighbor via a tube connecting the two cells. That means if your normal flora that are not harmful carries antibiotic resistance genes there is a chance that they may pass those genes along to harmful strains that cause infection.
“Superbugs” can be difficult or impossible to treat and often cause more severe disease with a higher mortality rate. It is crucial that attempts are made to ensure the correct administration and curb the overuse of antibiotics. Prof David Livermore of the Health Protection Agency in the UK predicts that it may be less than 10 years until there is wide spread resistance to our ‘last resort’ class of antibiotics, the carbapenems. Alternative treatments or preventative measures such as bacteriophage therapy and vaccines are in development; however, we must be vigilant as Mother Nature has proven herself to be highly adaptable to all of our best efforts.