So why all the fuss about MRSA now? People have been contracting bacterial infections as long as there have been people, and the miraculous discovery of antibiotics goes way back to work done in the 1920’s and even earlier. Presumably bacteria have always had the ability to circumvent man’s defenses and to adapt to the remedies we use against them?
The mid-twentieth century was the true “glory days” as far as humans vs. bacteria goes. We had finally moved beyond folklore and home remedies into the age of antibiotics – purified substances that had a demonstratable ability to kill bacteria and fight infections. And the beauty of it was that we didn’t have access to just one antibiotic….after the purification of penicillin in the 1920’s a 70+ year “explosion” of antibiotic development ensued which saw well over 50 distinct drugs introduced to fight infection. While the first experimental creations of antibiotic-resistant bacteria were reported as far back as 1943, why worry when our drug companies were capable of creating a new drug almost each year? In fact, between roughly the 1940’s and 1970’s there was really no reason to believe that bacteria in general should be a major problem in 1st world societies ever again.
In the early 1980’s antibiotic resistant infections were first reported in North America among intravenous drug users in major urban population centers. Obviously the problem has only grown from there, with MRSA ultimately spreading from the hospital into the community. I’ll spare you the stats of MRSA growth over the last 20 years, since they’re all over the internet anyway and I’ve talked about that aspect in previous posts. What I want to address here is the “why” and “how” parts of the question. If bacteria were becoming resistant to second line antibiotics (beta-lactams and cephalosporins), why didn’t we just phase them out and develop and whole bunch more to replace them? In essence, why did we let the problem get out of control? Questions like this are difficult to answer, even in retrospect, but there are a few issues that almost certainly contributed to the problem. Firstly, despite the proliferation of new antibiotics in the beginning, it should never be assumed that new drug development is an easy undertaking. By the 1970’s most of the low-hanging fruit, with respect to novel antibiotic substances, had been plucked and scientists were forced to go much further into sythetic chemistry and high-throughput screening to identify new compounds. Secondly, agencies such as the US Food and Drug Administration that control drugs and medicines have become vastly more strict in their approval requirements. The level of testing and expenditure required to bring a single antibiotic to market today are unlike anything that existed 40 or 50 years ago. In fact, incredibly, due to tighter FDA regulation it has become more expensive to bring an antibiotic drug to market than most other classes of drugs.1 This, at the same time that antibiotic resistance is growing into a major public health concern!
But the problem of antibiotic resistance and MRSA emergence doesn’t end with the FDA and drug companies. The Washington DC based “Center for Global Development” released a report recently2 that identified two of the major causes of increasing antibiotic resistance as inappropriate use of medicines and excessive use in agriculture. Have you ever gone to the doctor because you didn’t feel well, and after a few minutes of looking in your ear and feeling your stomach had him send you off with a prescription for some antibiotics. I’m sure almost everyone has experienced this at some point. The fact is that doctors prescribe antibiotics for about 80% of throat, ear, respiratory, and sinus ailments that are presented to them.3 Often times antibiotic use in these situations is warranted, but too often the diagnosis is unsure and the attitude is that sending a patient away with something will make them happy and at least won’t have a negative effect. While this type of practice seems harmless on an individual basis, the aggregate effect of overprescription of antibiotics is ultimately widespread bacterial resistance. In a similar, and probably even larger, misuse of our precious remaining effective drugs the agricultural industry routinely doses livestock with antibiotics. It has been estimated that 70% of all the antibiotics administered in the US are to livestock!4 What’s worse, this practice is largely unregulated and unrestricted. Furthermore, if you’re worried about the animals you have good reason to – antibiotics are used as “growth promotants” to allow the livestock to beef up to maximum levels while being kept in overcrowded and unhealthy conditions. In summary, there is little doubt that misuse of antibiotics in both humans and animals has been a major contributor to bacterial resistance and emergence of MRSA.
There is little doubt that several practices must change if antibiotic development and use are to keep up with bacteria’s ability to develop resistance. In addition, for the first time in decades we are being forced to look at alternative methods for fighting infections caused by strains such as MRSA. Hopefully, a combination of studious antibiotic use in the future and discovery of non-resistance forming interventions will continue to give us the edge in this battle.
1 Rubin PH, “The FDA’s Antibiotic Resistance” Regulation, Winter 2004-2005, pg 34-37.
2 Nugent R, Beck E, Beith A (2010) “The Race Against Drug Resistance”. A Report of the Center for Global Development’s Drug Resistance Working Group. http://www.cgdev.org/content/publications/detail/1424207
3 ScienceDaily (July 27, 2007) Antibiotic Resistance: Doctors’ Antibiotic Prescribing Practices Still Contributing To Problem. http://www.sciencedaily.com/releases/2007/07/070726091218.htm