Drug Resistant

The reduced effectiveness of antibiotics is hampering the control of infectious diseases. Resistance to penicillin, the first antibiotic, is still increasing. About a decade ago, penicillin did not kill the bacgteria, streptococcus pneumoniae, in 36.2 per cent of people in Singapore. That number has grown to 40 per cent now. In Singapore, streptococcus pneumoniae is a major cause of pneumonia.

As the world health organization marked World Health Day in April with the theme of antimicrobial resistance, it underscored how the battle between humans and microbes has been waged for years. The microbes have been gaining since penicillin resistance in streptococcus pneumoniae was discovered in 1977. Since then several superbags which are resistant to multiple antibiotics have evolved. An example of a superbag which is resistant to multiple antibiotics is methicillin-resistant staphylococcus aureus ( MRSA ), of which there are high levels here. 

Last year, the global emergence and spread of New Delhi metallo-betalactamase-1 (NDM-1) has added to an increasing list of resistance mutations. The national and global health concern is that antibiotic resistance, which reduces the effectiveness of treatment, hampers the control  of infectious diseases. Patients remain infectious for longer, which increases the potential for spreading resistant microorganisms to others. Futhermore, antibiotic resistance is under-recognised here, according to an editorial published in the Annals Academy of Medicine.

Other antibiotics still work

Pharmaceutical company GlaxoSmithKline is midway through a study which, while confirming penicillin's effectiveness is decreasing, has found that 98.5 per cent of streptococcus pneumoniae strains can still be effectively treated with its antibiotics called amoxicillin-clavulanate and amoxicillin.The study started in 2009 and is expected to be concluded in 2013.  Some 185 samples were collected from patients diagnoses with respiratory tract infections, such as bronchitis and sinusitis. The preliminary results were presented at the eighth international symposium on antimicrobial agents & resistance in Seoul, South Korea. 

If a patient, is still unwell after taking amoxicillin, he should return to his doctor, who will be able to adjust the treatment accordingly. If amoxicillin does not work, it is appropriate to change to amoxicillin-clavulanate. The reason is that there are other organism such as influenzae H and moxarella catarrhalis which cannot be adequately treated with amoxicillin alone. The use of amoxicillin-clavulanate will allow better eradicaton of other likely germ that cause respiratory tract infection. Amoxicillin alone will not be effective in treating all of them. Bacteria has become resistant to amoxicillin by digesting it with an enzyme called beta-lactamase. Scientists then created an anti=beta-lactamase-clavulanate to inhibit the enzyme. It blocks the digesting enzyme so the amoxicillin can act.