Antibiotics are molecules mainly produced by soil microorganisms, however, some antibiotics are synthetic and some are semi synthetic, and therefore, they can be produced in laboratories. Antibiotics can be cidal which kill bacteria or static which inhibit bacterial cell growth (Baker et al., 2006). However, not all antibiotics inactivate all bacteria as some bacteria are resistant to one and some are resistant to more than one antibiotic so they are called multi-drug resistant bacteria. Moreover, some bacteria are naturally resistant to some antibiotics but others have developed resistance.
Development of resistance to antibiotics was first reported soon after the first antibiotic (penicillin) was discovered where Staphylococcus aureus showed resistance to it in 1946. This was followed by streptomycin resistant Mycobacterium tuberculosis in 1947 (Yogesh et al., 2007). In 1953, during a shigella outbreak, multidrug resistant Shigella dysenteriae was discovered in Japan (Todar, 2009), followed by vancomycin resistant enterococci in the 1980’s. Later, in the 1990’s penicillin resistant S. pneumoniae was seen in the United States (Billeter, 2004). Then, in September 2002, two strains of vancomycin-resistant Staphylococcus aureus were isolated in Japan and the USA (Bozdogan et al., 2003). In 2002, Staphylococcus aureus also became resistant to vancomycin from transferrable genes in enterococci although it was already methicillin resistant (MRSA) and so is now vancomycin resistant Staphylococcus aureus (VRSA). Then, in 2005, outbreaks of C. difficile strains were reported to be resistant to fluoroquinolones (Loo et al., 2005). Cephalosporin-resistant gonorrhoea was also reported very recently in 2011, mainly to ceftriaxone (CDC, 2011).
Today antibiotic resistance is a major problem in hospitals and the community, more so than ever now, as people who would have survived five or ten years ago are now dying of infections due to antibiotic resistant bacteria. Furthermore, the heavy use of antibiotics in hospitals, care homes and farms increases the levels of resistance of bacteria in people and animals, including individuals who live near epicentres of high consumption or pass through them (Brown, 2002). Resistance can also be transferred between bacteria and when individuals are continually exposed to resistant bacteria; other bacteria in their body may also acquire resistance.
Other major reasons of multidrug resistance becoming an increasing problem globally, would be increasing rates of HIV infection contributing to the rise of MDR-TB (Moore, 2001), also weakened immune systems such as sufferers of autoimmune diseases or recovery from surgery contribute to increasing cases of MRSA (Greenwood et al., 2007). Whereas, in cases such as VRE, an alteration in the chemical composition of the cell wall can give rise to resistance as vancomycin can no longer bind to the bacterial cell wall and prevent its growth (Brown, 2002).
Lastly, β-lactamase producing bacteria produce beta-lactamase enzymes which open up the lactam ring of the antibiotic and inactivate it, so it has no effect (Shnayerson and Plotkin, 2003).
Therefore, prevention methods have been suggested, which include the optimal use of antibiotics to prevent bacteria surviving and acquiring resistance. Another measure was to prescribe alternative treatment for example for colds antibiotics are not needed. In addition, increasing education and awareness among health professionals and patients may deter the prescribing of antibiotics unless necessary and encourage increasing immunity through probiotics. Regular reviews of antibiotic policies have also been suggested as putting antibiotics on a restricted use regimen can prevent resistance increasing. Lastly, five guidelines were suggested by the Agency for Healthcare Research and Quality (AHRQ) in the USA to prevent the emergence of healthcare-associated infections (Collins, 2008). However, further research is required into the causes of multidrug resistance in order to fully understand the problem and tackle it.
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