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|Drug: The Double Edged Knife (Part 7)|
Mohamed H. Dahir (Chairman Pharmaceutical Association of Somaliland)
Antimicrobial resistance (Continued)
As early as half a century ago - just few years after penicillin was put on the market - scientists began noticing the emergence of a penicillin-resistant strain of staphylococcus aureus, a common bacterium in the human body’s normal bacterial flora. Resistant stains of gonorrhoea, dysentery-causing shigella (a major cause of premature death in developing countries) and salmonella rapidly followed. From that first case of resistant staphylococcus, the problem of antimicrobial resistance has snowballed to a serious public health concern with economic, social and political implications that are global in scope, and cross all environmental and ethnic boundaries, Multidrug-resistant tuberculosis (MDR/TB) is no longer confined to any one country or to those co-infected with HIV, but has appeared in locations as diverse as Africa, Asia and Eastern Europe, among health care workers and in general population.
Penicillin-resistant pneumococci are likewise spreading rapidly, while resistant malaria is on the rise, disabling and killing millions of children and adults each year.
In 1990 almost all cholera isolates in New Delhi, India, were sensitive to cheap, first line drugs furazolidine, ampicillin, co-trimoxazole and nalidixic acid. Now, formerly effective drugs are largely useless in the battle to contain cholera epidemics.
Although most drugs are still active, the lengthening shadow of resistance means that many of them may not be for long. In case of tuberculosis, the emergence of multidrug resistant bacteria means that medication that once cost US$20 must now be replaced with drugs a hundred times more expensive.
Pathogens develop resistance to antimicrobials through a process known as natural selection. When a microbial population is exposed to an antibiotic, more susceptible organisms will succumb, leaving behind only those resistant to the antimicrobial onslaught. These organisms can then either pass on their resistance genes to their offspring by replication, or to other related bacteria through "conjugation" whereby plasmids carrying the genes "jump" from one organism to another. This process is a natural, unstoppable phenomenon exacerbated by the abuse, overuse and misuse of antimicrobials in the treatment of human illness and in animal husbandry, aquaculture and agriculture. Disease - and therefore resistance - also thrives in conditions of civil unrest, poverty, mass migration and environmental degradation where large numbers of people are exposed to infectious diseases, with little in the way of the most basic health care. Our challenge is to slow the rate at which resistance develops and spreads.
To be continued next week