MULTIDRUG RESISTANCE BY MICROORGANISMS: A REVIEW
Multiple drug resistance (MDR) is the ability of some microorganisms to resist the actions of multiple antimicrobial agents. MDR include those resistant to multiple antibacterial, antifungal, antiviral, and anti-parasitic drugs. Similar activities of some microorganisms to certain chemical (drug) that would normally kill them or limit their growth is called antimicrobial resistance (AMR). Multi drug resistance can be classified as primary resistance, secondary resistance, intrinsic resistance, extensive resistance and clinical resistance. The classes of antibiotics that fall victim of resistance include beta-lactams, glycopeptide, aminoglycosides, sulphonamides, cephalosporins etc. The mode of action of antimicrobial drug includes cell wall synthesis inhibitors, protein synthesis inhibitor, blockage of key metabolic pathways, nucleic acid synthesis inhibitors etc. Bacteria often become resistant and this could be through one of several biochemical mechanisms such as mutation, destruction or inactivation and efflux or genetic transfer of materials between bacteria by several means such as conjugation, transformation and transduction. The mode of action of MDR protozoa occurs through decrease of drug uptake, the export of drugs from the parasite by P-glycoproteins and other traffic ATPases etc. The mode of action of MDR helminths occurs through genetic changes in the drug target, changes in drug transport, drug metabolism etc. The mode of action of antiviral drugs usually target viral DNA polymerase having the reverse transcriptase activity to inhibit the viral replication. The mode of action of MDR fungi occurs as they have learnt to modify the antifungal drug targets or most commonly increase the efflux of the incoming drugs There are various ways to reverse this resistance such as washing hands after seeing each patient, the public should wash raw fruit and vegetables thoroughly to clear off both resistant bacteria and possible antibiotic residues, avoid the misuse of antibiotics etc.