Typhoid Fever Dr. KHALID ALJARALLAH

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1 Dr. KHALID ALJARALLAH

2 Main objectives General characteristics (G-, Rod, Facultative anaerobe..etc,) Natural Habitat and transmission root Symptoms Pathogenicity Diagnosis and treatment Prevention

3 Characteristic & natural habitat of Salmonella Daniel E. Salmon, First described in 1880 Enterobacteriaceae cultured at about 37 C on ordinary culture media, ph range 4.05 to 9.0 (optimum 7.0), where they develop small colonies 2 to 4 mm in diameter Common in the gastrointestinal tracts of mammals, reptiles, birds, and insects

4 Characteristic & natural habitat of the organism Gram-negative facultative anaerobes bacilli (enteric rods) Motile peritrichous flagella Non-lactose fermenting

5 Characteristic & natural habitat of the organism H 2 S producing Typhoid Fever affects 17 million people worldwide every year, with 600,000 deaths (common in children < 5 years old in developing countries)

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7 Taxonomy Old: Serotyping & biochemical assays used to name individual species within genus (e.g., Salmonella enteritidis, S. typhi) Over 2400 O-serotypes (referred to as species) (Kauffman-White antigenic scheme)

8 Taxonomy New: based on DNA-DNA hybridization : only two species 1- Salmonella enterica (six subspecies) S. enterica subspecies enterica (Ex. Typhi, Paratyphi) 2- Salmonella bongori Ex. Salmonella typhimurium should be S. enterica serovar Typhimurium, or simply Salmonella Typhimurium (note that typhimurium is capitalized and not italicized). Most pathogens (99%) are belongs to S. enterica ssp. enterica

9 Habitat, sources & transmission human-to-human contaminated foods. The most common sources of salmonellae are beef, poultry, and eggs Improperly prepared fruits, vegetables, dairy products, and shellfish

10 Habitat, sources & transmission

11 Symptoms The main clinical syndromes induced by Salmonella species are: - enteric fever - bacteremia and - the carrier state.

12 Symptoms Fever- step ladder pattern Headache Abdominal discomfort Altered bowel habit Malaise and lethargy Relative bradycardia at the height of temperature GI bleed due to intestinal perforation Typhoid Encephalopathy/ Shock

13 Pathogenicity Typhoid Fever Pathogenesis Typhoid bacilli adhere and penetrate the mucosa of the intestine, and transit to the basal membrane. Invade the Peyer s patches inflammation and, sometimes, gut ulceration. Besides being phagocytozed by mononuclear cells in regional lymph nodes, typhoid bacilli cause a transient bacteremia and spread to the liver and spleen. Within the macrophage they steadily multiply, are released and initiate a period of continuous bacteremia.

14 Pathogenicity Typhoid Fever Pathogenesis (cont.) Enteric Fever is characterized by prolonged fever, invasion of liver, spleen, kidney and gallbladder. Higher severity and mortality in children < 5 years old. Gallbladder is frequent sites of persistent infection in carriers.

15 Pathogenicity Non Typhoid Salmonellosis Pathogenesis (cont) Penetrate mucosa lamina propria and often enter the bloodstream. multiply in the lamina propria induce fluid secretion diarrhea. normally do not cause sustained bacteremia ( coz they are killed by phagocytic cells).

16 Pathogenicity Non Typhoid Salmonellosis Pathogenesis (cont) symptoms typically occurs 8 to 24 hours after ingestion of contaminated food infection is characterized by abdominal pain, fever and diarrhea that last for 3 to 5 days. Generally, self-limiting, recovery within one week. Major causes of childhood bacteremia, often in association with focal sepsis.

17 Pathogenicity From: Ralph A. Giannella (Salmonella) ;

18 Diagnosis & treatment Non Typhoid Salmonella : stool specimen. A number of selective media are routinely used, Ex. MacConkey agar, eosin-methylene blue (EMB) agar, HE agar, SS agar, and xylose-lysine-deoxycholate (XLD) agar..

19 Diagnosis & treatment Typhoid fever, S typhi or S paratyphi may be isolated from stool, urine, or rose spot biopsy and from gastric or intestinal secretions, although blood and bone marrow aspirates have the highest yields Widal test Salmonella species may be differentiated by conventional biochemical assays, phage typing, and serological typing.

20 Symptoms

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22 Diagnosis & treatment Hematology: approximately one fourth of patients with typhoid fever are leukopenic, neutropenic, or anemic

23 Chloramphenicol, The selection of ampicillin, co-trimoxazole, quinolone derivatives or Third generation cephalosporins

24 Diagnosis & treatment S.N. Al-Bahry,1 A.E. Elshafie,1 S. Al-Busaidy,2 J. Al-Hinai3 and I. Al-Shidi Antibiotic-resistant Salmonella spp. from human and non-human sources in Oman, Eastern Mediterranean Health Journal, Vol. 13, No. 1,

25 Prevention Safe water and food Proper food handling and personal hygiene Avoidance of cross contamination Cooking foods to appropriate temperatures Placing foods in the refrigerator promptly Vaccination (in developing countries)

26 Main objectives General characteristics (G-, Rod, Facultative anaerobe..etc,) Natural Habitat and transmission rout Symptoms Pathogenicity Diagnosis and treatment Prevention