MULTI DRUG RESISTANCE

Multi drug resistant (MDR) micro-organisms that resist the action of antimicrobial drugs (antibiotics). This is a critically important issue as it can make the treatment of infections more difficult and increase hospital costs. Increasing numbers of infections are developing that cannot be treated, and many existing antimicrobial agents are becoming less effective. In addition, the development of new anitbiotics is at an all time low.

In a few instances, micro-organisms are naturally resistant to antimicrobial drugs, but a more common problem is when a micro-organism that is naturally susceptible to the action of particular antimicrobial agents develops resistance. The problem is attributed to excessive use of antibiotics, which eliminate competing susceptible micro-organisms allowing the resistant strains to proliferate.

Examples of antimicrobial resistant organisms include methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus, Enterococcus, Pseudomonas aeruginosa, Clostridium difficile, Mycobacterium tuberculosis[italics] and others.

MRSA (methicillin-resistant Staphylococcus aureus)

Gram-positive bacterium that can occur on skin and inside the nostrils in healthy individuals. If it invades the body, MRSA can cause septicaemia, pneumonia, osteomyelitis and endocarditis. Detected in 1961, MRSA is spread by skin-to-skin contact and is resistant to common antibiotics.

NDM-1

In late August 2010 Lancet Infectious Diseases reported a new type of ‘superbug’ resistant to the carbapenem antibiotics used on hard-to-treat infections such as MRSA. Resistance is conferred by the NDM-1 (New Delhi metallo-ß-lactamase-1) enzyme, which is capable of destroying antibiotics and can be transferred between types of bacteria leading to acquired antimicrobial resistance. It is most often seen in the Gram-negative bacteria E. coli and Klebsiella pneumoniae.

Bacteria with the NDM-1 mutation have been found in UK patients recently returned after receiving medical treatment in India and Pakistan, where resistance has become increasingly common. Infections have been mild to severe, some have been fatal. Similar infections have occurred in the USA, Canada, Australia and the Netherlands. Most work on new antibiotics is with Gram-positive organisms such as MRSA, and international researchers say that NDM-1 could become a major global health problem.