Ampicillin typhoid fever

Typhoid fever caused by Salmonella typhi or S. paratyphi is an important and prevalent cause of continuous fever without localizing symptoms in the tropics. The diagnosis can be confirmed with a bloodculture. Response on therapy is often seen only after 3 days when the fever subsides. Chloramphenicol-resistant Salmonella typhi was first described in Vietnam in 1973. Its prevalence reached 95% in the 1970s and then decreased to 54% in the 1980s after cotrimoxazole became the treatment of choice. In the mid-1993, there was a dramatic increase in the number of strains of S. typhi, isolated in the hospital and from patients in the outbreaks, which are resistant to the three first-line antibiotics chloramphenicol, cotrimoxazol and ampicillin. This indicated that there was an urgent need for effective antibiotics for the treatment of typhoid fever. 

TMP-SMX is also used in the treatment of infection caused by ampicillin-resistant Shigella spp. and for antibiotic-resistant Salmonella spp.. The combination is also effective for covering the carrier state of Salmonella typhi, the agent of typhoid fever, and other Salmonella spp.. Successful treatment of traveler s diarrhea due to susceptible E. coli is another advantage of the use of this combination. The combination is not indicated in the therapy of enterohemorrhagic E. coli strains such as 0157 H7 because of the risk of developing hemolytic-uremic syndrome associated with the release of the cytotoxic enterotoxin by the drugs. 

Currently there are no commercially available vaccines for salmonellosis, but vaccines for typhoid fever are given to travelers going to countries with endemic disease. For most strains of Salmonella spp., antibiotics (specifically ampicillin, gentamicin, ciprofloxacin, and a combination of trimethoprim and sulfamethoxazole) are effective for both typhoid fever or severe salmonellosis some serotypes... 

Antibiotics indicated in the treatment of typhoid fever are ceftriaxone 1 g/kg M or IV b.i.d. and fluoroquinolones such as ciprofloxacin 500 mg PO b.i.d. or levofloxa-cin 500 mg or IV for 10-14 days. Fluroquinolones may be also administered in children. Chloramphenicol is still used but aplastic anemia is a consideration. Other antibiotics which are used depending on sensitivity are trimethoprin-sulfamethoxazole, amoxicillin, ampicillin, azithromycin and aztreonam. 

One of the worrisome issues in the treatment of typhoid fever is the emergence of Salmonella typhi strain resistant to ampicillin, amoxicillin and chloramphinicol. There are also reports of resistance to fluoroquinolones and multidrug resistance. This threat places a high priority for prevention and control of typhoid fever by sanitary measures, especially safe water and sewage disposal, as well as the development of new drugs. 

Typhoid fever and similar salmonellal infections are usually considered the prime indications for the use of chloramphenicol. It is also employed in acute infections due to Heamophilus influenzae, including meningitis attributed to ampicillin-resistant strains. It also find its enormous applications in topical infections of eye and skin. It has also been used to eradicate vibrios from patients with cholera. It is employed for rickettsial infections like typhus and Rocky Mountain spottedfever. 

Despite potentially serious limitations, chloramphenicol is an effective drug when used carefully. Its special value is in typhoid fever, Haemophilus infections (especially epiglottitis and meningitis, when given along with ampicillin), rickettsial infections, and in cases in which susceptible organisms have proven to be... 

Salmonella paratyphi is a bacterial enteric (intestinal) infection with an abrupt outbreak, which produces the following symptoms continued fever, headache, malaise, enlarged spleen, rose spots on the trunk of the body, and diarrhea. These symptoms are similar to those of typhoid fever, but the death rate is much lower. Mild and asymptomatic infections may also occur upon exposure. Outbreaks and locations are similar to those of the other salmonella bacteria. The infectious dose is 1000 organisms by ingestion. Transmission occurs by direct or indirect contact with feces or, in rare cases, urine of patients or carriers. It is spread by food, especially miUc and dairy products, shellfish, and in some isolated cases, water supplies. Incubation depends on the strength of the dose, but usually 1-3 weeks for enteric fever and 1-10 days for gastroenteritis. Antibiotic treatment with chloramphenicol, ampicillin, or TMP-SMX is usually effective. 

Chloramphenicol remains a major treatment of typhoid and paratyphoid fever in developing countries. However, with increasing resistance to ampicillin, trimethoprim-sulfamethoxazole and, to some extent, chloramphenicol, fluoroquinolones and some third-generation cephalosporins (e.g., ceftriaxone) have become the drugs of choice. Salmonella infections, such as osteomyelitis, meningitis and septicemia, have also been indications for chloramphenicol use. Nevertheless, antibiotic resistance patterns can be a problem. As noted previously, nonty-phoidal salmonella enteritis is not benefited by treatment with chloramphenicol or other antibiotics. 

---