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Difference between revisions of "Phage therapy"
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: Neisseria gonorrhoeae is a facultative intracellular pathogen that is able to infect the eye, pharynx, anus/rectum, urogenital tract, and may be disseminated throughout the body in more complex cases. The Center for Disease Control reports that in 2011 there were an 321,849 new cases of gonorrhea reported in the U.S.<ref>[http://www.cdc.gov/std/gonorrhea/STDFact-gonorrhea-detailed.htm] Detailed STD Facts </ref> of which about 50% are estimated to be reported ( for a total of 700,000 estimated new cases in 2011). The World Health Organization reports that there are between 65-105 million new cases of gonorrhea nationally each year. Of these, 0.5-3% of cases develop into disseminated, systemic infection where the falcutative intracellular diplococci induce more serious illness such as pelvic inflammatory disease. | : Neisseria gonorrhoeae is a facultative intracellular pathogen that is able to infect the eye, pharynx, anus/rectum, urogenital tract, and may be disseminated throughout the body in more complex cases. The Center for Disease Control reports that in 2011 there were an 321,849 new cases of gonorrhea reported in the U.S.<ref>[http://www.cdc.gov/std/gonorrhea/STDFact-gonorrhea-detailed.htm] Detailed STD Facts </ref> of which about 50% are estimated to be reported ( for a total of 700,000 estimated new cases in 2011). The World Health Organization reports that there are between 65-105 million new cases of gonorrhea nationally each year. Of these, 0.5-3% of cases develop into disseminated, systemic infection where the falcutative intracellular diplococci induce more serious illness such as pelvic inflammatory disease. | ||
== Antibiotic | == Antibiotic Resistant Gonorrhea == | ||
: | :Until recently, gonorrhea treatment was simply a matter of picking the right antibiotics; however, that is quickly ceasing to be the case. Gonorrhea is currently one of the most common treatable STDs in the United States, but soon it may be just one of the most common STDs. The number of gonorrhea cases resistant to treatment with antibiotics has continued to rise, and scientists are quickly running out of options. Single-dose antibiotics for gonorrhea treatment are quickly becoming a thing of the past. | ||
Gonorrhea, otherwise known as the clap, often seems like nothing more than a nuisance, particularly since it is so frequently asymptomatic, but that won't continue to be the case if we run out of antibiotics to treat it. Left untreated, gonorrhea can lead to serious problems. It is, for example, a major cause of pelvic inflammatory disease and infertility. Gonorrhea can also lead to an infection known as disseminated gonorrhea and cause problems in pregnant women and infants. | |||
Because gonorrhea is so common, doctors would like to be able to treat it with a single, effective dose of medication. Single-dose gonorrhea antibiotics reduce problems with drug compliance that can increase the prevalence of antibiotic resistance, and also decrease the need for follow-up. Unfortunately, one-dose regimens may soon no longer be an option. The affordable antibiotics that have been widely used to treat gonorrhea in the past are losing effectiveness against a growing number of strains. Although it is still possible to find an antibiotic that can treat individual cases of gonorrhea, the choices are narrowing as multi-drug-resistant strains of the bacteria continue to appear. At this point, American doctors have been recommended to stop giving oral antibiotics as a primary treatment and switch over to an injectable cocktail. | |||
The specific types of antibiotic-resistant gonorrhea strains seen in the U.S. and around the world vary from year to year, city to city, and population to population. Some scientists hope that by eliminating use of gonorrhea antibiotics that are becoming ineffective, strains that are resistant to those drugs will decrease in prevalence so that the drugs will become useful once again. Scientists have to hope, because they are quickly running out of drugs. In late 2012, the scientists reported that the last, effective oral antibiotic used to treat gonorrhea had begun to fail. In one clinic in Ontario, up to 7 percent of patients were not effectively treated with cephalosporins. | |||
In a few years, gonorrhea treatment will cease to be a simple process. Kicking an infection may require course after course of antibiotics, followed by repeated testing to see which, if any, of the antibiotics have worked. At that point, your best option will be one that you also have right now -- consistently practicing safe sex to avoid getting infected in the first place. | |||
Antibiotics That Are No Longer Recommended For Gonorrhea Treatment | |||
Sulfonamides - Over a period of only 9 years, 30 percent of gonorrhea strains became resistant to treatment with sulfonamides. They stopped being used in the mid-1940s and were replaced by penicillin. | |||
Penicillin - Although initially quite effective, required penicillin doses for gonorrhea treatment climbed significantly over time, until eventually, in the 1980s, U.S. doctors stopped using penicillin to treat gonorrhea. | |||
Tetracycline - In the 1980s, tetracycline also ceased being a first-line treatment option due to the spread of treatment-resistant gonorrhea strains. | |||
Fluoroquinolones (ciprofloxacin, ofloxacin, levofloxacin) - In 2007, the CDC changed their gonorrhea treatment guidelines to remove single-dose fluoroquinolones from the recommended list. Fluoroquinolone-resistant strains have been identified around the world, including in many areas of the U.S. The prevalence of fluoroquinolone-resistant gonorrhea in California went from less than one percent of infections in 1999 to over 20 percent in 2003. | |||
Oral Cephalosporins (ceftriaxone, cefixime) - Cephalosporin-resistant gonorrhea strains were first identified in Asia and Australia and have been slowly becoming more common around the globe. As of August 2012, oral cephalosporins are no longer recommended for the treatment of gonorrhea in the United States. Between 2006 and 2011, the percentage of gonorrhea strains resistant to these drugs went up more than ten-fold in many areas of the U.S. Cefixime is no longer recommended for gonorrhea treatment at all, except in cases where ceftriaxone can not be used. | |||
Antibiotics Currently Used to Treat Gonorrhea | |||
Combination Treatment with Injectable Cephalosporins - As of August, 2012, the recommended treatment for gonorrhea is one injection of 250 mg ceftriaxone. This is combined with either a single oral dose of 1 g azithromycin or a week of taking 100 mg oral doxycycline twice a day. To date, few gonorrhea strains are resistant to both types of antibiotic. However, this not be true forever. There are alternate treatment regimens available for people allergic to ceftriaxone, but they require patients to return for a second test to make certain they have been cured. | |||
== Bacteriophages == | == Bacteriophages == | ||
:Bacteriophage (phage) is a virus that infects bacteria host cells. Viruses are acellular microbes that are obligate intracellular pathogens; requiring living cell hosts to carry out metabolic and reproductive needs. Bacteriophages carry with them a protein coat called a capsid that surrounds a small amount of DNA genetic material. The size of the DNA can vary from 5 genes to over 100 genes (3). The majority of the genes on phage DNA code for capsid proteins, proteins to protect viral DNA from degradation, and proteins used in the release from the host cell (3, 4). Because phage cannot reproduce or undergo metabolism on their own, they must infect living bacteria cells in order to reproduce. As part of their reproductive cycle, phages kill the bacteria cell they are infecting. There are two main types of reproductive cycles that a phage can use: the lytic cycle and the lysogenic cycle. A typical phage lytic cycle consists of five main steps. The first step is attachment. The attachment occurs between the phage and a receptor or structure on the surface of the bacterial cell. Attachment is very specific for the bacteriophage, with each phage being able to only infect one species of bacteria. After attachment is entry and this is where the phage DNA enters into the cytoplasm of the bacteria cell. Once inside the bacteria cell, the phage takes over the metabolic machinery of the cell, degrades the bacteria DNA, and changes the cell into a phage producing factory. The viral DNA is translated and viral proteins are made in the synthesis part of the viral cycle. In addition to translation, viral DNA is also being replicated to produce more viral DNA. Once enough viral capsid proteins and viral DNA are synthesized, the assembly part of the cycle occurs. During assembly, the viral capsid proteins surround the viral DNA to build more bacteriophage. When enough bacteriophage particles have been assembled, the release phase occurs. During the release phase, the host cell lysis open, releasing numerous bacteriophage into the environment. The bacteriophage can then go and attach to another bacteria host cell to repeat the lytic cycle over and over again until no bacteria are available for attachment. | :Bacteriophage (phage) is a virus that infects bacteria host cells. Viruses are acellular microbes that are obligate intracellular pathogens; requiring living cell hosts to carry out metabolic and reproductive needs. Bacteriophages carry with them a protein coat called a capsid that surrounds a small amount of DNA genetic material. The size of the DNA can vary from 5 genes to over 100 genes (3). The majority of the genes on phage DNA code for capsid proteins, proteins to protect viral DNA from degradation, and proteins used in the release from the host cell (3, 4). Because phage cannot reproduce or undergo metabolism on their own, they must infect living bacteria cells in order to reproduce. As part of their reproductive cycle, phages kill the bacteria cell they are infecting. There are two main types of reproductive cycles that a phage can use: the lytic cycle and the lysogenic cycle. A typical phage lytic cycle consists of five main steps. The first step is attachment. The attachment occurs between the phage and a receptor or structure on the surface of the bacterial cell. Attachment is very specific for the bacteriophage, with each phage being able to only infect one species of bacteria. After attachment is entry and this is where the phage DNA enters into the cytoplasm of the bacteria cell. Once inside the bacteria cell, the phage takes over the metabolic machinery of the cell, degrades the bacteria DNA, and changes the cell into a phage producing factory. The viral DNA is translated and viral proteins are made in the synthesis part of the viral cycle. In addition to translation, viral DNA is also being replicated to produce more viral DNA. Once enough viral capsid proteins and viral DNA are synthesized, the assembly part of the cycle occurs. During assembly, the viral capsid proteins surround the viral DNA to build more bacteriophage. When enough bacteriophage particles have been assembled, the release phase occurs. During the release phase, the host cell lysis open, releasing numerous bacteriophage into the environment. The bacteriophage can then go and attach to another bacteria host cell to repeat the lytic cycle over and over again until no bacteria are available for attachment. | ||