For example, how are infections of antibiotic resistant strains of MRSA, Streptococcus, or Gonorrhea treated?
There are a number of ways to address antibiotic resistance in infectious bacteria. What one gets used depends on exactly what organism we're talking about. But below is a short list of some ways:
- Changing the antibiotic being used. Not all antibiotics have the same molecular target within a bacterial cell. Some interfere with the formation of the cell wall, others interfere with protein synthesis, some mess with DNA replication, etc. Similarly, resistance mechanisms don't work equally well on all antibiotics. So often the solution is simply to switch antibiotics. Or, quite often, treating all infections with a combination of drugs that should get around most resistance. This is why you see people getting skittish about things like multi-drug resistant organisms - because it removes this solution.
- This isn't as much a treatment as a preventative measure, but increasing antimicrobial stewardship and the appropriate use of antibiotics to prevent widespread resistance from arising in the first place.
- The use of non-antibiotic antimicrobials. The most "common" of these is phage therapy - using preparations of bacteriophages that naturally prey on the infecting pathogen to help combat the infection. This was a major "contender" for how we treated antibiotic infections, but has fallen away due to a bad reputation early in its history (due to difficulties purifying phage treatments) and the discovery of antibiotics which were vastly easier to use. But there's still ongoing research, and it may pose a potential to help treat highly resistant infections in the future.
As a former icu nurse and also a molecular biologist who specialized in genes for antibiotic biosynthesis I can tell you theory is world's apart from practicality. New antibiotics are least tested agents and very expensive, often the patient suffers more from the antibiotics side effects than they do from the infection. Monotherapy is basically old hat now, use of a single agent to treat massive drug resistant infection only increasea the odds of increasing drug resistance. The general rule now is combitherapy using two or more cheaper and better known antibiotics and save newer agents as a drug of last resort for future cases. We are rapidly evolving into a post antibiotic Era according to Dr Stuart Levy https://www.amazon.com/Antibiotic-Paradox-Antibiotics-Destroys-Curative/dp/0738204404
Combinations of antibiotics are now becoming essential due to quite widespread resistance to single antibiotics in bacteria such as MRSA, E coli, K pneumoniae and P aeruginosa. Physicians often give two or three antibiotics. However, few of the combinations used have actually been rigorously tested for safety and efficacy (hence widespread side-effects, as the former icu nurse reported above). The odd thing is that there is only one approved combination of two antibiotics available for Gram-negative bacteria, the combination of trimethoprim and sulfamethoxazole. This seems to be a very obvious gap that needs filling. Which other dual combinations would be very useful?