Turn recording back on. National Center for Biotechnology Information , U. StatPearls [Internet]. Search term. Salmonella Typhi John V. Author Information Authors John V.
Affiliations 1 Kingman Regional Medical Center. Continuing Education Activity Salmonella enterica typhi is a gram-negative bacterium that is responsible for typhoid fever and has been a burden on developing nations for generations. Introduction Salmonella enterica serotype typhi is a gram-negative bacterium that is responsible for typhoid fever and has been a burden on developing nations for generations.
Etiology Salmonella enterica serotype typhi is a gram-negative, rod-shaped, flagellated bacterium whose only reservoir is the human body. Epidemiology Typhoid fever is more common in children and young adults and is associated with low-income areas in which poor sanitation is prevalent.
Pathophysiology Salmonella enterica serotype typhi is usually contracted by ingestion of food or water that is contaminated with the excrements of people that carry the organism and must survive the gastric pH barrier in the stomach prior to adherence in the small intestine. History and Physical Patients will typically present after a 7 to day asymptomatic period after initial inoculation with Salmonella enterica serotype typhi.
Evaluation The diagnosis of typhoid fever should be suspected in those living in endemic areas or those who have traveled to an endemic area and are presenting with a febrile illness. Differential Diagnosis The differential diagnosis of those infected with Salmonella enterica serotype typhi should include: Malaria.
Prognosis The prognosis for patients with typhoid fever depends on how quickly the diagnosis is made and antibiotics are started. Deterrence and Patient Education Travelers to countries where Salmonella typhi is endemic should be educated on the importance of avoiding unpeeled fruits or vegetables and only drinking bottled or boiled water.
Pearls and Other Issues Relative bradycardia in response to a fever pulse-temp deficit has been reported in the literature. Ciprofloxacin or ofloxacin should be seen as the initial anti-microbial of choice in areas with low quinolone resistance. Enhancing Healthcare Team Outcomes Salmonella typhi infection is best managed by an interprofessional team that includes infectious disease nurses and clinicians.
Review Questions Access free multiple choice questions on this topic. Comment on this article. Figure Rose spots on the chest of a patient with typhoid fever due to the bacterium Salmonella typhi. References 1. Barnett R. Typhoid fever. Clin Microbiol Rev.
N Engl J Med. Burden of typhoid fever in low-income and middle-income countries: a systematic, literature-based update with risk-factor adjustment. Lancet Glob Health. The global burden of typhoid fever. Bull World Health Organ. Typhoid fever in the United States, Typhoid fever acquired in the United States, epidemiology, microbiology, and use of a space-time scan statistic for outbreak detection.
Epidemiol Infect. Typhoid; clinical analysis of cases. Arch Intern Med Chic. M cells in Peyer's patches of the intestine. Int Rev Cytol. Edelman R, Levine MM. Summary of an international workshop on typhoid fever. Rev Infect Dis. Bhutta ZA. Current concepts in the diagnosis and treatment of typhoid fever. Salmonella Typhi. In: StatPearls [Internet]. In this Page. Related information. Similar articles in PubMed.
Typhoid fever associated with acute appendicitis caused by an H1-j strain of Salmonella enterica serotype Typhi. J Clin Microbiol. Salmonella Typhi outer membrane protein STIV is a potential candidate for vaccine development against typhoid and paratyphoid fever. Epub Mar The diagnostic accuracy of three rapid diagnostic tests for typhoid fever at Chittagong Medical College Hospital, Chittagong, Bangladesh.
Trop Med Int Health. Epub Jul Clin Infect Dis. After ingestion, Salmonella penetrates the small intestine and multiplies in the lymph nodes or intestinal lymphoid tissues without causing any serious clinical damage.
The release of Salmonella into lymphatic vessels or bloodstream of the human host leads to bacteraemia or septicaemia and other associated infections.
The carriage of Salmonella in the bloodstream may also affect other vital organs of the body such as the spleen, liver and the heart. Salmonella is toxigenic and thus releases endotoxin which increases its virulence in the affected human host. Usually, headache, prolonged fever, constipation in some cases and malaise may ensue following an infection with S.
Infected human hosts release large amounts of S. Typhi in their faeces during the infective stage, and some treated individuals can remain asymptomatic and continue to shed the pathogen in their faeces. Asymptomatic carriers of Salmonella species are highly infectious because they can remain undetected for a long period of time spanning into years during which they may have transmitted the pathogen to susceptible human hosts.
Salmonella Typhimurium serovar is the main causative agent of food-borne Salmonella infection otherwise known as Salmonella gastroenteritis or enterocolitis. Salmonella gastroenteritis is a food-poisoning and diarrheal disease typically prevalent in developed countries although it occurs in developing countries with varying frequency due to their cultural engagement in picnic and other outdoor activities.
It is a limiting Salmonella infection, and can disappear after several days of infection even without prior antibiotic therapy. Cooked food especially salads and vegetables can serve as proper culture media for the propagation and transmission of Salmonella to human hosts, and this usually occurs when food contaminated with the pathogen is eaten or consumed. Salmonella Typhimurium is reserved in animals unlike S. Typhi that only inhabit humans , and it can be transmitted from poultry products, diary and meat products to humans.
Typhimurium occurs in the intestinal tract of birds and other animals including humans. Typhimurium occurs via the consumption of contaminated egg, water, food, meat and other poultry or dairy products containing large amount of viable Salmonella Typhimurium serovar 10 5. Following invasion, S. Typhimurium enters the large and small intestine where they proliferate and cause inflammatory reactions that result in a diarrheal-like disease.
The production of enterotoxin and cytotoxin by S. Poor handling of food by food processing industries and food handlers can help S. Typhimurium to enter the food supply chain from where human infection ensues. Some of the symptoms of Salmonella gastroenteritis include diarrhea, fever, abdominal cramp, nausea, headache and vomiting and the passing out of loose-bloody faeces which is merely occasional.
The mode of transmission of S. Typhimurium is via the feacal-oral route. Vegetables and other food products should not be washed with feacal-contaminated water, and people should endeavour to eat only well cooked and pasteurized food and milk products.
The laboratory diagnosis of Salmonella infection is mainly based on the isolation and identification of the pathogen from clinically important specimen through cultural techniques. Serological tests based on agglutination methods can also be used for diagnosis of Salmonella infection. Faecal samples, blood, urine and the contaminated food sample are usually requested for laboratory analysis when Salmonella infection is suspected. Blood and faecal culture are routinely used in some quarters for the laboratory diagnosis of infections caused by Salmonella.
It also grows on eosin methylene blue EMB agar producing colourless colonies , on MacConkey agar producing non-lactose fermenting and pale colonies , on xylose-lysine-deoxycholate XLD agar producing pink-red colonies with H 2 S production in some serotypes and on Hektoen enteric HE agar producing blue-green colonies with H 2 S production.
Salmonella can also be identified in the laboratory by carrying out a number of biochemical tests such as culturing the bacteria in triple sugar iron agar TSIA or Kligler iron agar KIA medium as well as in other biochemical reagents which are commercially available.
Note: Hydrogen sulphide H 2 S production by bacteria including Salmonellais normally indicated by blackish deposits in or around the bacteria colonies growing on culture media especially Salmonella-Shigella agar SSA which is used for the selective cultivation of Salmonella species from stool specimens. Infection with Salmonella only confers a milder form of immunity in infected human hosts, and a re-infection can occur in individuals who are predisposed to the pathogen or its source of transmission.
However, protection against Salmonella infection usually follows a natural infection with the serovars of the pathogen. The antibiotics of choice for treating Salmonella infections include third-generation cephalosporins, ampicillin and sulphamethoxazole-trimethoprim. But the use of these agents should be guided by antimicrobial susceptibility testing to avoid the emergence and spread of drug resistant Salmonella strains. Fluid and electrolyte replacement is required for the treatment of Salmonella gastroenteritis or S.
Typhimurium infection which does not require any antibiotic treatment. Typhoid vaccines exist for people traveling to endemic regions. Since Salmonella Typhi and Paratyphi serovars are strictly human infections and are acquired through faecally-contaminated food, hands and water; their control and prevention in human population should be based on maintaining proper personal and environmental hygiene, as well as good public health.
Proper sewage control should be instituted and people should have access to quality toilets and other sanitary facilities both at home and in public places to avoid indiscriminate defecation. Constant food storage in the refrigerator usually at 4 o C is critical to the prevention and control of Salmonella enterocolitis in places where the disease is most prevalent.
Faecal samples of food handlers should be periodically screened for Salmonella as a preventive measure to break the asymptomatic carriage rate of the disease as well as its spread in human population. Travelers should avoid as much as possible uncooked food and vegetables in places where Salmonella infection is known to be endemic. Lastly, proper sanitation, treatment of infected individuals, proper sewage management, provision of clean drinking water and the education of the general public about the infection is critical to the prevention of Salmonella infection.
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