The Human Connection
The overuse of antibacterials is born from fear and misinformation. As the public became aware of the dangers of certain germs and bacteria, many people did not consider the presence of beneficial bacteria. However, the overuse of antibacterials often kills the 'good' bacteria, and makes the 'bad' bacteria stronger and more resistant (Levy 1998). And while most products advertise that they kill 99% of bacteria, the remaining 1% is able to mutate and grow.
Triclosan (TCS)
Triclosan (TCS) is an example of an active microbial in most soaps. Roughly 1 kg of triclosan is produced for every 3 kg of antibacterial product (Carey and McNamara 2015).
TCS-including products are primarily used in homes and hospitals for disinfectants. Exposure to TCS demonstrates the adaptive properties of bacteria, as two mutant forms of MRSA were shown to have mutated to have four-fold and 16-fold increases to the amount of TCS needed it inhibits the strains (Brenwald and Fraise 2003).
Antibacterial Leaching
The primary entryway for antibacterials to the environment is through wastewater. As with most compounds used by humans, antibacterials will eventually find their way into wastewater. Topical antibacterials such as soaps and gels (hand sanitizers) are inevitably washed off of skin and into the sewer systems. Because 100% removal of antibacterials is near-impossible in modern wastewater plants, some chemicals are left in runoff and sludge. The chemicals then enter water and soil, where they affect both natural habitats and the agriculture industry.
Technology for proper, or better, removal of these compounds from wastewater is possible with new technology. However, many wastewater processing plants are not willing to pay for the technology (Grenni et al. 2018).
What is a "superbug"?
Superbugs are created through the overuse of antibacterials. As bacteria become more resistant to antibacterial agents, they mutate into unkillable 'superbugs'.
How are "superbugs" made?
The image on the left shows the basic reproduction process of bacterial cells. The red is the bacterial DNA, where the green and blue are plasmids - DNA that can be absorbed from the environment. DNA will be passed on to all future generations of bacteria through replication and reproduction. Plasmids, however, will get passed on randomly to the next generation.
In this case, the green plasmid represents an antibiotic resistance gene, while the blue is an unrelated gene. With antibiotics, bacteria with only blue plasmids are killed off. The bacteria with antibiotic resistance are thus selected for in their environment.