Antibiotic Resistant Streptococci There Are More Than Term Paper

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Antibiotic Resistant Streptococci

There are more than thirty different species of streptococcal bacteria. The infections that strep causes in humans range from "strep throat," which is caused by Group A strep and relatively easily treatable, to diseases such as pneumonia and serious wound infections, both of which can prove deadly.(1)

Antibiotics were first developed during World War II, and have saved many millions of human lives since then that would have been lost to streptococci infections and diseases. Penicillin alone was solely responsible for dramatically decreasing mortality rates of soldiers wounded on the battlefields of World War II compared to corresponding rates of World War I casualties.

The widespread use of penicillin and more modern antibiotics that have been developed since World War II has been accompanied by the natural evolution of some bacterial strains that are resistant to antibiotics. In many respects, the natural ability of bacteria to develop antibiotic resistant strains has sparked an arms race of sorts between these microscopic human pathogens and the microbiologists who try to develop new chemotherapeutic antibiotic agents effective against them. Public health officials have been warning against the indiscriminant or inappropriate use of antibiotics in order to slow the evolution of antibiotic-resistant strains, which is particularly important, now that bacterial strains have evolved that seem resistant even to the newest and most powerful antibiotics.

1. Lopez, T. Study: Drug-resistant infections increasing in U.S. hospitals very large percentage of all human infections including strep throat, pneumonia, septicemia, skin and wound infections, scarlet fever, and toxic shock syndrome are caused by two bacteria: staphylococcus and streptococcus.(2) In 1929, Sir

Alexander Fleming discovered the antibiotic properties of penicillin mold on staphylococci bacteria and doctors began treating war wounds with penicillin during the Second World War. Penicillin first became widely available only after the war, and since then, antibiotics have revolutionized the treatment of many diseases because they have the remarkable ability to destroy disease-causing pathogens without harming the host patient.(3)

Antibiotic Resistant Streptococci:

Penicillin is effective primarily (only) against Gram-positive microorganisms such as streptococci, and it remains the first choice of antibiotic to treat infections caused by streptococci bacteria. Almost immediately, doctors noticed that other pathogenic organisms such as staphylococci bacteria developed a resistance to penicillin. Whereas as many as eighty percent of staphylococci bacteria eventually became resistant to penicillin, the progenitor of all antibiotics to follow remains largely effective against some such as Streptococcus pyogenes (Group A strep), but not against others (such as the so-called "flesh eating" bacteria).(4) Even

Streptococcus pneumonia, which causes inner-ear infections and the most serious forms of bacterial meningitis have recently begun exhibiting resistance to penicillin, after forty years of exposure to the drug.(5)

2. Todar, K. Bacterial resistance to Antibiotics

3. Hurst, L., Russell, S. Superbugs and nightmare scenarios: Resistance to antibiotics grows

4. Todar, K. Bacterial resistance to Antibiotics

5. Hurst, L., Russell, S. Superbugs and nightmare scenarios: Resistance to antibiotics grows

By the 1950's, bacteriological scientists had developed many new antibiotic drugs, including streptomycin, chloramphenicol, and tetracycline, which, unlike penicillin, were also effective against Gram-negative bacteria, as well as intracellular parasites and the tuberculosis bacillus.(6) Shortly after their development, a strain of dysentery bacillus that caused the 1953 outbreak of Shigella in Japan was isolated which exhibited resistance even to these new antibiotics, as well as to some of the newer sulfanilamides.(7)

In general, there are several mechanisms through which streptococci and other bacteria can either manifest or develop a resistance to antibiotic chemotherapeutic agents, among them, Inherent Resistance and Acquired Resistance (in the form of either Vertical Evolution or Horizontal Evolution).

Penicillin's ineffectiveness against Gram-negative bacteria is one example of an organism's natural resistance to antibiotic agents. Gram-negative bacteria are protected by an external membrane that renders the cells' outer walls impermeable to the penicillin molecule. Other natural forms of resistance include cell transport systems and metabolic reactions that are just not susceptible to the mechanism through which the drug is intended to work.(8)

Vertical Evolution is simply the evolution through principles of natural selection via spontaneous mutation, the mechanism underlying natural selection, first postulated by Charles Darwin in the nineteenth century. Bacterial evolution differs from that of larger animals in one very important respect, which accounts for a particularly fast development of new strains: Bacterial organisms multiply at a much

6. Todar, K. Bacterial resistance to Antibiotics

7. Ibid.

8. Ibid.

A faster rate than do larger animals. Consequently, whereas a population of mammals incorporates beneficial mutations over a matter of years, bacterial populations multiply so fast that beneficial mutations can arise in less than an hour.(9)

The other mechanism through which bacteria evolve antibiotic resistance is gene exchange, achieved through one of the three forms of so-called horizontal evolution: cell conjugation, transduction, and transformation. They rely on cell-to- cell contact, direct intercellular gene exchange, and indirect gene exchange, respectively.(10)

Medical Healthcare Implications:

According to the Harvard School of Public Health, forty percent of streptococci infections in the United States will be resistant to both penicillin, and erythromycin by the summer of this year.(11) The Centers For Disease Control had been warning for years that some staphylococcus infections are already resistant to all known antibiotics except vancomycin, the so-called last resort against some virulent staphylococci. Linezolid, the first truly new antibiotic produced in several decades, was introduced in 2001; it had encountered bacterial resistance within months.(12)

Hospitals are deadly breeding grounds for common staphylococci bacteria that are responsible for the transmission of blood poisoning, pneumonia, and devastating post surgical wound infections. Penicillin is virtually useless against almost all of them, so they are more often treated with methicillin. Methicillin resistant strains now cause millions of infections in hospitals in the United States,

Todar, K. Bacterial resistance to Antibiotics

10. Ibid.

11. Tampa Tribune; March 13, 2003

12. Hurst, L., Russell, S. Superbugs and nightmare scenarios: Resistance to antibiotics grows with fatal consequences as many as one in twenty.(13) By the summer of 2002, the first case of vancomycin resistant bacteria appeared in Michigan, with more certain to follow shortly.(14)

Paradoxically, the streptococcal organism responsible for strep throat still responds to penicillin, even after forty years. Patients allergic to penicillin must rely on a class of antibiotics called macrolides, including erythromycin, clarithromycin and azithromycin. A Pittsburgh study reported in early 2004 found macrolide- resistant strep throat cultures in ten percent of pediatric strep throat cases in one hospital, and rates of four or five percent have previously been recorded in other facilities throughout the United States.(15)

Sometimes, bacterial antibiotic resistance can be overcome by holding back use of the agent or combining multiple antibacterial chemotherapeutic agents together. The New England Journal of Medicine reported last year that authorities in Finland had reduced the incidence of antibiotic resistant streptococci infections

Significantly after instituting regulations limiting antibiotic use, but these are considered temporary, "stop gap" measures pending ongoing research into new, stronger drugs, which is a slow process. Given the exponential growth rate and large communities of bacterial organisms, it is impossible to compete with nature, in this realm. Medical experts continually caution that research into new antibiotics is only half the battle; the other half requires eliminating preventable causative practices and oversights that contribute to the problem.(16)

13. Hurst, L., Russell, S. Superbugs and nightmare scenarios: Resistance to antibiotics grows

14. Ibid.

15. Srikameswaran, A. Higher rate of antibiotic resistance here puzzles researchers

16. Ibid.

Preventable Causes of Antibiotic Resistant Bacterial Evolution:

One of the worst contributing factors to the rapid evolution of antibiotic resistant bacteria is antibiotic over-prescription. Each year, doctors write approximately 100 million antibiotic prescriptions. According to public health officials, as many as half of those are absolutely unnecessary. Doctors often over-prescribe antibiotics to satisfy patients requests, even for symptoms that are likely the result of common cold viruses or non-bacterial ear…

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