Typhoid fever S. typhi

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. 

Because of bone marrow toxicity of chloramphenicol, its use is restricted to the treatment of infection caused by S. typhi and paratyphi (treatment of typhoid fever). 

Enterobacter,c Proteus, Yersinia (Y. pestis, plague), Escherichia, Klebsiella, Salmonella (S. typhi, typhoid fever), Serratia, Shigella (S. dysenteriae, bacterial dysentery), Haemophilus Vibrio (V. cholerae, Asiatic cholera) Zym.om.onas... 

Salmonella enterica (S. enterica) is a rod-shaped Gram-negative facultative anaerobe and a prominent enteric bacterial pathogen capable of causing food- and water-related diseases. Several serovars of S. enterica are associated with human infection. The principle clinical diseases associated with Salmonella infection are typhoid fever and gastroenteritis. S. enterica serovars Typhi S. Typhi) and Paratyphi (,S. Paratyphi) are pathogenically exclusive for humans and are known to cause typhoid or enteric fever (Ohl and Miller, 2001). Typhoid fever is a systemic infection characterized by the development of fever, abdominal pain, enterocolitis, and occasionally, a maculopapular rash. The hallmark feature of typhoid fever is the presence of mononuclear cell infiltration and hypertrophy of the intestinal Peyer s patches and mesenteric lymphoidal tissue (Kraus et al., 1999 Ohl and Miller, 2001). There are approximately 20 million cases of typhoid fever worldwide each year, and this acute and often life-threatening infection is responsible for over 200,000 deaths annually (Crump et al., 2004). 

The onset of symptoms of Salmonella gastroenteritis is usually 6-72 h. Acute symptoms may last for 1-2 days or may be prolonged depending on host factors, ingested dose, and strain. Arthritic symptoms may occur 3 weeks after onset of acute symptoms. Symptoms are more severe in the elderly, infants, and immunocompromised individuals. S. typhi and S. paratyphi A, B, and C produce typhoid and typhoid-like symptoms in humans. Enteric fever (typhoid fever) may develop other symptoms include anorexia, abdominal pain, malaise, myalgias, headache, cough, diarrhea or constipation, and... 

The third-generation cephalosporins (e.g., ceftriaxone, ceflxime, cefotaxime, and cefoperazole) and azithromycin are also effective drugs for typhoid. Chloramphenicol, amoxicillin, and trimethoprim-sulfamethoxazole remain appropriate for the treatment of typhoid fever in areas of the world where the bacterium is still fully susceptible to these drugs and where the fluoroquinolones are not available or affordable. Although fluoroquinolones are not recommended in children, the pediatric use of ciprofloxacin in areas where multidrug-resistant S. typhi occurs is acceptable. In pregnant women, the p lactam antibiotics are safe, and there are some case reports to support fluoroquinolone use. 

Typhoid fever is an illness caused by infection with Salmonella typhi. Typhoid is spread via the fecal-oral route. Clinical illness in its severe form is characterized by gradually rising fever that reaches 39 to 41°C (102.2 to 105.8°F) and persists for up to 2 weeks. Headaches, abdominal discomfort, malaise, myalgia, and anorexia usually are present. Older children and adults usually have constipation, whereas diarrhea is common in infants. Complications include intestinal perforation and hemorrhage. Between 2% and 5% of patients become chronic gallbladder carriers of S. typhi. 

Laboratory diagnosis is based on stool culture and isolation of salmonella serotype. Blood culture may be also positive in bacteremic phase. For typhoid fever, the Widal test is used to measure antibodies against O and H antigens S. Typhi. 

Systemic and local immune responses, humoral and cellular, are mounted by the host but these are not associated with host protection. Necrosis of Peyer s patches, which may lead to intestinal perforation, is attributed to interaction of bacterial factors and host immune response. It is also interest that in typhoid fever there is no strong association with HIV infection, whereas in HIV infection there is an increased incidence of non-typhi Salmonella infection. Headache, pharyngitis and arthralgia may be present. Gastrointestinal symptoms are usually constipation, abdominal pain and tenderness. Other symptoms which may occur are diarrhea, the pea soup type containing inflammatory mononuclear cells. The biliary tree and liver is involved presenting cholecystitis and hepatitis. Splenomegaly may develop. 

Typhoid fever is caused by the entry of the pathogen S. typhi into gastrointestinal epithelial cells. This entry process is apparently mediated through the cystic fibrosis transmembrane regulator, a chloride channel of the ATP cassette family of proteins, since cells that expressed the mutant nonfunctional 508phenylanine deletion did not take up as much pathogen as wild-type cells (Pier et al., 1998). 

Like E. coli, Salmonella spp. is a member of the Enterobacteriaceae family often isolated from humans and food products. The various types of Salmonella spp are known pathogens. S. typhi causes typhoid fever while other species cause diarrhea or even septicemia. Its detection and identification therefore is important for food safety. Common food products that harbor Salmonella spp include eggs or poultry products that have not been properly processed or cooked. 

Salmonella Typhi lives only in humans. Persons with typhoid fever carry the bacteria in their bloodstream and intestinal tract. In addition, a small number of persons, called carriers, recover from typhoid fever but continue to carry the bacteria. Both ill persons and carriers shed S. Typhi in their feces (stool). 

Persons with typhoid fever usually have a sustained fever as high as 103° to 104° F (39° to 40° C). They may also feel weak, or have stomach pains, headache, or loss of appetite. In some cases, patients have a ra.sh of flat, rose-colored spots. The only way to know tor sure if an illness is typhoid fever is to have samples of stool or blood tested for the presence of S. Typhi. 

Salmonellae can exist for long periods outside their host, and maybe found, for example, in sewage and surface water. Humans may become infected by consuming contaminated water or food, especially animal products, such as eggs, meat, and milk, or vegetables that have been fertilized with contaminated manure. The bacteria can also be transmitted from human or animal carriers by unhygienic food preparation. Various species of Salmonella cause gastroenteritis and septicaemia typhoid fever and paratyphoid fever are caused by S. typhi and S. paratyphi, respectively. 

The O antigen extracted from S. typhi with trichloroacetic acid precipitated more antibodies from anti-fS. typhi) sera than did the degraded polysaccharide extracted with acetic acid. The heterogeneity of lipopolysaccharides from strains of S, typhi isolated from carriers and patients with typhoid fever has been demonstrated by Immunoelectrophoresis. ... 

Typhoid, caused by S. typhi infection, presents as a high stepwise fever associated with bacteraemia and development of the pathognomonic signs of a truncal rash with salmon-coloured maculopapular lesions after around 1 week. Typical symptoms also include myalgias, abdominal pain and constipation. 

Specific Salmonella serotypes produce characteristic human disease. For example S. enterica serotypes Typhimurium or Enteri-tidis causes gastroenteritis, whereas serotypes Typhi or Paratyphi causes enteric fever. Clinical manifestations produced by Salmonella serotypes commonly include acute gastroeuteritis (euterocolitis), bacteremia, extraiutestiual locahzed iufectiou, euteric fever (typhoid aud paratyphoid fever), aud a chrouic carrier state. 

Salmonella typhi S. paratyphoid Typhoid salmonellosis High fever, diarrhea, enlargement of liver and spleen Contaminated water or milk eating food or drinking sewage-contaminated water... 

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