Salmonella chronic carriers

Human disease caused by Salmonella generally falls into four categories acute gastroenteritis (enterocolitis), bacteremia, extraintestinal localized infection, and enteric fever (typhoid and paratyphoid fever), and a chronic carrier state. S. typhimurium is the most common cause of salmonellosis. Salmonellosis is a disease primarily of infants, children, and adolescents. 

Some patients may continue to shed Salmonella for 1 year or longer. These chronic-carrier states are rare for serotypes other than S. typhi. 

The drug of choice for chronic carriers of Salmonella is norfloxacin, 400 mg orally twice daily for 28 days. 

Salmonella usually remains in the intestines for up to 5 weeks - and in some cases for many months. Be aware that some individuals can become chronic carriers of Salmonella bacteria and 2% may develop chronic arthritis. Good personal hygiene and handwashing techniques would prevent the majority of transmissions. Wash hands thoroughly with warm, soapy water after visits to the restroom and before food preparation. 

Stool cultures inevitably yield the causative organism if obtained early (i.e., in patients hospitalized less than 3 days). Recovery of organisms continues to decrease with time so that by 3 to 4 weeks, only 5% to 15% of adult patients are passing Salmonella. Infants and children tend to pass bacteria for longer periods than adults. Some patients may continue to shed Salmonella for a year or longer. These chronic carrier states are rare for serotypes other than Typhi. ... 

Chronic carriers of Salmonella usually have negative stool cultures at 12 weeks after the onset of illness, but some may have continued positive stool cultures at 6 to 12 months. Chronic fecal shedding of Salmonella has been associated with chronic biliary infection... 

Salmonella typhi is a human pathogen. The mode of transmission is by contamination of water by fecal excretion, but it is also transmitted from person to person by hands and contact with infected patients. Food handlers who carry Salmonella typhi pose an increased risk of transmission of infection. Salmonella typhi are excreted in the stool of chronic carriers who may be asymptomatic as well as in the stool and urine in patients with active disease. Outbreaks of typhoid fever are associated with inadequate sanitary infrastructures in developing countries due to inadequate measures of hygiene. Contamination of water in the community is the main source of infection in endemic areas. In developed countries the main source of contamination is by food supplies infected by carriers. Flies and lack of adequate standards of proper disposal of waste may also account for the spread of infection. 

It is estimated that 3-5% of untreated patients become carriers of S. typhi. Chronic carriers pose a significant pool of infected individuals with Salmonella typhi, because they shed bacilli for a long period. The risk is enhanced since these carriers are difficult to identify because the majority are asymptomatic. Furthermore, Salmonella typhi colonize the gallbladder and biliary tree and they are excreted in the stool by the enterohepatic circulation. Even the removed of the gallbladder is not always an effective measure to abolish the carrier state, since Salmonella typhi spread to the intrahepatic bile ducts. Identification of carriers is important in order to contain and limit the transmission to healthy individuals. Carrier s state is confirmed by isolation of Salmonella typhi in stool culture. Treatment of carriers with amoxicilhn, trimethoprim-sulfamethoxazole or ciprofloxacin is indicated. 

Administration Most sulfa drugs are well absorbed after oral administration. Sulfasalazine [sul fa SAL a zeen], when administered orally or as a suppository, is reserved for treatment of chronic inflammatory bowel disease (for example, Crohn s disease or ulcerative colitis), because it is not absorbed. Similarly, succinylsulfathiazole [suks in ill sul fa THI a zole] is used for the treatment of salmonella and shigella carriers. Intravenous sulfonamides are generally reserved for patients who are unable to take oral preparations. Because of the risk of sensitization, sulfas are not usually applied topically. In burn units, creams of mafenide acetate (p-aminomethylbenzensulfonamide) or silver sulfadiazine have been effective in reducing burn sepsis. However, superinfections with resistant bacteria or fungi may occur. 

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. 

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