Cheap Cosmetic Surgery with a Side of Antibiotic Resistance

On the many occasions you have a chesty cough and visit the GP, you may be contributing to the age-old problem of antibiotic resistance without realising it. Providing you take your antibiotics properly you won’t personally experience any ill effects. However antibiotics are being over prescribed in Europe and this is contributing to the problem. The topic has been pretty quiet in the press recently, especially as the number of deaths from MRSA is falling. So is antibiotic resistance still a problem?

As mentioned, providing you take your antibiotics properly, you shouldn’t experience any problems because the bacteria (assuming it is not viral infection) will not have time to adapt to the antibiotics. A gap in the medication schedule gives the bacteria a quiet period in which they can obtain and express genes that will aid their resistance to the antibiotics. This is the basis of all resistance, not just in bacteria, but also in pesticides, fungicides, and even in cancer drug resistance.

The mechanism of antibiotic resistance lies with the bacterial cell wall. Bacteria must build and maintain a functional cell wall for their survival. Therefore this is a good target for antibiotics. Many modern antibiotics, including penicillin, actually hinder the machinery used by the bacteria to construct the cell wall. For the bacteria to become resistant it must be able to overcome the antibiotic. There are three main mechanisms by which bacteria can do this. Firstly, they can adapt the cell wall machinery in order to render the antibiotic ineffective. This, in fact, is the main mechanism adopted by MRSA. The second mechanism involves drug permeability: bacteria can stop the antibiotic entering the cell in the first place by altering the cell wall to make it less permeable and by producing drug efflux pumps that pump antibiotics out.

However, it is the third pathway that currently stands to be the biggest clinical threat in antibiotic resistance. This mechanism involves the production of enzymes called β-lactamases which can digest antibiotics thus rendering them useless. Current research efforts are aimed at producing drugs that inhibit these enzymes to be taken alongside regular antibiotics. In fact compounds that do this, such as sulbactam and tazobactam, are already being mixed in with the antibiotics being prescribed at the moment. So, you may ask then, why are β-lactamases posing such a threat if there are already drugs to inhibit them?

There is a new emerging β-lactamase class of enzyme called New Delhi β-lactamase (NDM), which is able to digest all known clinical antibiotics. The enzyme was first discovered in 2008 in a Swedish patient with pneumonia who later died of a recurrent infection. Slowly more and more cases have been reported, with one feature in common: the patients had recently been in Indian hospitals (one study showed that 17 of 29 selected UK patients found to be harbouring NDM had recently been to the Indian subcontinent). The naming of this enzyme has already received a lot of controversy, as there is no proof that the enzyme originated in India. However the fact that NDM was detected in 4% of drinking water samples and 30% of sewage seepage in New Delhi, compared to 0% and 7% respectively for Cardiff, suggests that the country may be the source of the problem.

It should be noted that many of the patients mentioned above had undergone corrective cosmetic surgery. Perhaps they opted for this after they heard in the press that they would save the NHS money. In the long term, treating patients in India would in fact probably cost the NHS more, as they would likely receive an increased number of cases of people with resistant strains of pnemonia or other bacterial infections. In the meantime, researchers – including some here in Oxford – are pooling a lot of effort into researching NDM and other β-lactamases in an attempt to find new inhibitors. Until then, proposals to set up healthcare links with India should be avoided.