Multi-drug resistant Bacteria

The development of resistance to antibiotics in bacteria often develops as a result of unnecessary and inappropriate use of antibiotics. Antibiotics have been critical in the fight against infectious disease caused by bacteria and other microbes in the past 60 years. Disease-causing microbes that have become resistant to antibiotic drug therapy are an increasing public health problem. At the present time, about 70 percent of the bacteria that cause infections in hospitals are resistant to at least one of the drugs most commonly used for treatment. An alarming increase in resistance of bacteria that cause community acquired infections has also been documented, especially in the staphylococci and pneumococci (Streptococcus pneumonia. Multi-drug resistance (MDR) is defined as insensitivity or resistance of a microorganism to the administered antimicrobial medicines (which are structurally unrelated and have different molecular targets) in spite of earlier sensitivity to it. If the bacterial strains resistant to three or more classes of antimicrobials, it is considered as multi-drug resistant. Studies from WHO report have shown very high rates of resistance in bacteria such as Escherichia coli against antibiotics as cephalosporin and fluoroquinolones, Klebsiella pneumoniae against cephalosporin and carbapenems, Staphylococcus aureus against methicillin, Streptococcus pneumoniae against penicillin, and Mycobacterium tuberculosis against rifampicin, isoniazid, and fluoroquinolone. Multidrug resistance in bacteria may be generated by one of two mechanisms. First, these bacteria may accumulate multiple genes, each coding for resistance to a single drug, within a single cell. This accumulation occurs typically on resistance (R) plasmids. Second, multidrug resistance may also occur by the increased expression of genes that code for multidrug efflux pumps, extruding a wide range of drugs.