Typhoid fever is an infectious disease caused by the bacteria Salmonella typhi. The Centers for Disease Control and Prevention, or CDC, estimates a worldwide incidence of 22 million cases and 200,000 deaths annually. It occurs less commonly in the United States, with a yearly estimate of only 400 cases. The CDC further states that the use of antibiotics results in a shorter duration of illness and reduced risk of death from typhoid fever. The emergence of drug resistance, however, has led to problems in antibacterial choices for therapy.
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Formerly one of the three first-line drugs together with amoxicillin and trimethoprim-sulfamethoxazole, chloramphenicol has lost favor as drug of choice for typhoid fever because of increasing rates of drug resistance. The World Health Organization, or WHO, reports on its association with a high relapse rate of 5 to 8 percent, as well as the development of a chronic carrier state in which a person whose symptoms have resolved continues to test positive for the bacteria and remains infectious.
In an article from the July 2006 issue of the British Medical Journal, Dr. Zulfiqar Bhutta wrote that chloramphenicol still produces satisfactory cure rates for drug sensitive typhoid fever. Dr. Bhutta recommends the restriction of use of other drugs such as fluoroquinolones in these cases to prevent the development of further drug resistance.
Amoxicillin is a well-tolerated drug that can be given orally or injected into the muscle or vein. Dr. Bhutta reports that its use in typhoid fever has a relapse rate ranging from 4 to 8 percent.
Trimethoprim-Sulfamethoxazole, or TMP-SMX, can be taken orally or injected into the vein. The WHO reports that a 6-week treatment with TMP-SMX can effectively treat up to 60 percent of chronic carriers.
Fluoroquinolones include ciprofloxacin, levofloxacin and norfloxacin. These drugs are considered the drug of choice for treatment of typhoid fever in both children and adults according to the WHO. Reports of resistance to fluoroquinolones have steadily increased, especially in India and other parts of Asia. As such, they should not be used in areas of high resistance until laboratory tests show that the infecting bacterium is susceptible to the drug.
The use of ciprofloxacin in chronic carriers can result in clearance of the bacteria in up to 80 percent of cases, as reported by the WHO.
Ceftriaxone is an injectable antibiotic that becomes the drug of choice together with other third generation cephalosporins in cases where the possibility of fluoroquinolone resistance is high, states the CDC. Serious side effects like allergic reactions and jaundice, or yellowing of the skin, can occur with use.
Azithromycin is also used for treating typhoid fever in adults and children, according to the WHO. Together with ceftriaxone and other third generation cephalosporins, it can effectively treat cases resistant to the first line drugs and fluoroquinolones.