Laboratory diagnosis of typhoid fever

×Top Health Categories • Coronavirus Disease COVID-19 • Gastrointestinal Health • Artificial Intelligence • Heart Disease • Mpox • High Blood Pressure • Allergies • Lung Cancer • Alzheimer's & Dementia • Mental Health • Arthritis & Rheumatology • Pregnancy • Breast Cancer • Type 1 Diabetes • Cold, Flu & Cough • Type 2 Diabetes • Diet & Nutrition • Sexual Health • Eating Disorders • Sleep • Eye Health • By Dr. Ananya Mandal, MD Reviewed by Typhoid fever is diagnosed by testing for antibodies produced against the bacteria Salmonella typhi, which causes the condition. In most countries where the disease is widespread, treatment is started based on symptoms while these tests are processed by the laboratory to confirm the presence of disease. An outline for the diagnosis of typhoid fever is given below: • Assessment to check for typhoid fever symptoms. • Any history of similar infection within the patient's social circle or family is obtained as are the details of any recent travel to countries where typhoid is prevalent. Endemic areas include countries in Africa, the Indian subcontinent, South East Asia, and South America. • Blood, stool and urine samples are collected so they can be checked under the microscope for the presence of Salmonella typhi. However, the bacteria may not always be detected in the early stages of disease and a series of tests may be needed to confirm the diagnosis. • Testing the bone marrow is a more reliable method for diagnosing typhoid. However, obta...

Typhoid fever is an illness you get from S. Typhi bacterium. It causes a high fever, flu-like symptoms and diarrhea. You can be contagious with typhoid even if you don’t feel sick. Typhoid can be life-threatening and should be treated promptly with antibiotics. If you live in or travel to an area where typhoid is common, you should get vaccinated. Overview Typhoid fever starts with a fever that gets progressively higher over a few days. Other symptoms follow as the bacteria spreads in your body. What is typhoid fever? Typhoid fever is an illness caused by the bacterium Salmonella Typhi ( S. Typhi). It infects your small intestines (gut) and causes high fever, stomach pain and other symptoms. Typhoid fever is also called enteric fever. You’ll commonly hear paratyphoid fever mentioned along with typhoid. Paratyphoid fever is similar to typhoid with more mild symptoms. It’s caused by Salmonella Paratyphi ( S. Paratyphi). S. Typhi and S. Paratyphi are different than the Salmonella bacteria that cause Who does typhoid fever affect? Typhoid fever is most common in rural areas of developing countries where there isn’t modern sanitation. Countries in South and Southeast Asia, Central and South America, Africa and the Caribbean are most affected by typhoid. Travelers are most at risk when visiting Pakistan, India or Bangladesh. Children are more likely to get typhoid than adults. How common is typhoid fever? It’s estimated that 11 million to 21 million people around the world get t...

• Disease caused by Salmonella species infection • While overlap exists, species causing typhoid fever and nontyphoidal species are often categorized separately • Salmonellosis is a food borne disease caused mainly by Salmonella typhi serotype, although Salmonella paratyphi A, B, C can cause similar disease • Salmonella penetrate the small bowel epithelium after ingestion, enter lymphoid tissue and disseminates via the lymphatic or hematogenous route • Typhoid fever is characterized by severe systemic illness with fever, relative bradycardia and considerable constitutional symptoms including abdominal pain ( • Causes intestinal bleeding due to ulcers in distal ileum or proximal colon ( • Bleeding may be massive ( • Salmonellosis is considered a food borne disease • Typhoid fever: • Sometimes known as enteric fever, is a life threatening illness caused by Salmonella typhi sometimes called Salmonella enterica serotype Typhi or S. paratyphi • Infects from 20 to 30 million people a year, mostly in the developing world • In industrialized countries, it is usually encountered in travelers • Nontyphoid species: • Usually cause acute, self limited gastroenteritis • The Centers for Disease Control and Prevention (CDC) estimates that one million cases, 19,000 hospitalizations, and 450 deaths occur each year in the United States • Tens of millions of cases occur worldwide each year causing an estimated 100,000 deaths • Disease is spread through ingestion of contaminated food or water...

Diagnosis Medical and travel history Your health care provider may suspect typhoid fever based on your symptoms, and your medical and travel history. The diagnosis is often confirmed by growing the Salmonella enterica serotype typhi in a sample of your body fluid or tissue. Body fluid or tissue culture A sample of your blood, stool, urine or bone marrow is used. The sample is placed in an environment where bacteria grow easily. The growth, called a culture, is checked under a microscope for the typhoid bacteria. A bone marrow culture often is the most sensitive test for Salmonella typhi. Treatment Antibiotic therapy is the only effective treatment for typhoid fever. Commonly prescribed antibiotics The medicine you get to treat typhoid fever may depend on where you picked up the bacteria. Strains picked up in different places respond better or worse to certain antibiotics. These medicines may be used alone or together. Antibiotics that may be given for typhoid fever are: • Fluoroquinolones. These antibiotics, including ciprofloxacin (Cipro), may be a first choice. They stop bacteria from copying themselves. But some strains of bacteria can live through treatment. These bacteria are called antibiotic resistant. • Cephalosporins. This group of antibiotics keeps bacteria from building cell walls. One kind, ceftriaxone, is used if there is antibiotic resistance. • Macrolides. This group of antibiotics keeps bacteria from making proteins. One kind called azithromycin (Zithromax)...

Typhoid fever is caused by certain types of the Overview of Gram-Negative Bacteria Bacteria are classified by how they appear under the microscope and by other features. Gram-negative bacteria are classified by the color they turn after a chemical process called Gram staining... read more Salmonella. It typically causes a high fever and abdominal pain. (See also Overview of Bacteria Bacteria are microscopic, single-celled organisms. They are among the earliest known life forms on earth. There are thousands of different kinds of bacteria, and they live in every conceivable... read more and Infections The gram-negative bacteria Salmonella typically cause diarrhea and sometimes cause a more serious infection, typhoid fever. People are usually infected when they eat contaminated food... read more .) People who are infected excrete the bacteria in stool and, rarely, in urine. A few infected people develop chronic infection of the gallbladder or urinary tract. They continue to excrete the bacteria in stool or urine, even though they no longer have any symptoms. Such people are called carriers. Thus, they do not know they can spread the infection. During the early 20th century, one such woman, a cook named Mary Mallon, spread typhoid fever to many people and became known as Typhoid Mary. The bacteria spread from the digestive tract to the bloodstream (causing Bacteremia Bacteremia is the presence of bacteria in the bloodstream. Bacteremia may result from ordinary activities (such...

Blood, intestinal secretions (vomitus or duodenal aspirate), and stool culture results are positive for S typhi in approximately 85%-90% of patients with typhoid fever who present within the first week of onset. They decline to 20%-30% later in the disease course. In particular, stool culture may be positive for S typhi several days after ingestion of the bacteria secondary to inflammation of the intraluminal dendritic cells. Later in the illness, stool culture results are positive because of bacteria shed through the gallbladder. Stool culture alone yields a sensitivity of less than 50%, and urine culture alone is even less sensitive. Cultures of punch-biopsy samples of rose spots reportedly yield a sensitivity of 63% but may remain positive even after administration of antibiotics. A single rectal swab culture upon hospital admission can be expected to detect S typhi in 30%-40% of patients. S typhi has also been isolated from the cerebrospinal fluid, peritoneal fluid, mesenteric lymph nodes, resected intestine, pharynx, tonsils, abscess, and bone, among others. Bone marrow aspiration and blood are cultured in a selective medium (eg, 10% aqueous oxgall) or a nutritious medium (eg, tryptic soy broth) and are incubated at 37°C for at least 7 days. Subcultures are made daily to one selective medium (eg, MacConkey agar) and one inhibitory medium (eg, Salmonella-Shigella agar). Identification of the organism with these conventional culture techniques usually takes 48-72 hours ...