Minggu, 08 Mei 2011
Classification and morphologySalmonella sp. is the kingdom Bacteria,
phylum Proteobacteria,
Salmonella sp. The first was found (observed) in patients with typhoid fever in 1880 by Eberth and justified by the Robert Koch in the cultivation of bacteria in 1881 (Todar, 2008). Salmonella sp. is a bacterial form of rod, on gram staining pink (gram negative). Salmonella sp. size of 2 μ to 4 μ × 0, 6 μ, has a flagellum (excluding S. gallinarum and S. pullorum), and not berspora (Julius, 1990). Habitat Salmonella sp. is in the digestive tract (small intestine) of humans and animals. The optimum temperature growth of Salmonella sp. is 37oC and at pH 6-8 (Julius, 1990).In the Kauffman and White scheme nomenclature of Salmonella sp. are regrouped based on the antigen or the DNA of enteric group I, II salamae, arizonae IIIa, IIIB houtenae, IV diarizonae, bongori V, and VI indica. Salmonella sp DNA base composition is 50-52 mol% G + C, similar to the Escherichia, Shigella, and Citrobacter (Todar, 2008). But the classification or use of nomenclature that is often used on Salmonella sp. based on epidemiology, host type, and type of antigen structure (eg S.typhi, S. thipirium). Type or species of Salmonella sp. the main thing is S. typhi (one serotype), S. choleraesuis, and S. enteritidis (more than 1500 serotypes). Sedangkang species S. paratyphi A, S. paratyphi B, S. included in S. paratyphi C enteritidis (Jawezt et al, 2004).Figure 1 morphology Sallmonella sp. :
(Jawezt et al, 2004)
Antigen Structure
Salmonella sp. has three main kinds of antigens for diagnostic or identify which are: somatic antigen (O), flagella antigen (H) and Vi antigen (kasul) (Todar, 2008). O antigen (Cell Wall antigens) is a phospholipid protein complex heat-resistant polysaccharide (thermostable), and acid alcohol (Julius, 1990). The antibodies formed are IgM (Karsinah et al, 1994). But O is less immunogenic antigens and agglutination was slow (Julius, 1990). So not good for serologic antigen because there are 67 factors, each species has a number of factors (Todar, 2008). Therefore O antibody titer after infection was lower than in antibody H (Julius, 1990).H antigen in Salmonella sp. divided in 2 phases ie Phase I: Specific and phase II: non-specific. H antigens are proteins that are not heat resistant (thermolabile), can be destroyed by heating above 60 º C and acid alcohol (Karsinah et al, 1994). H highly immunogenic antigen and IgG antibodies are formed (Julius, 1990). While the Vi antigen is a polymer of an acidic polysaccharide. There is a section outside of the body most germs bersifai thermolabile. Can be destroyed by heating 60 ° C for 1 hour. Germs that have to be virulens Vi antigen in animals and mausia. Vi antigen also determines the sensitivity to bakteriofaga and in the laboratory are very useful for rapid diagnosis of germ S. typhi (Karsinah et al, 1994). The existence of Vi antigen indicates the individual is a carrier of germs (carrier) (Julius, 1990).
Biochemical propertiesSalmonella sp. are aerobic and anaerobic falkultatif, the growth of Salmonella sp. at 37 ° C and at pH 6-8. Salmonella sp. have a flagellum so on motility test result is positive, the BAP media (Blood To Plate) cause hemolysis. On MC media (Mac Conkay) did not ferment lactose or called Non Lactose fermenter (NLF), but Salmonella sp. ferment glucose, mannitol and maltose with acid and gas formation, except S. typhi is not menghasikkan gas. Then the media indole negative, MR positive, negative Vp and citrate positive possibilities. Not menghidrolisiskan urea and produce H2S (Julius, 1990).
PathogenicitySalmonellosis is a term that indicates an infection of Salmonella sp. Clinical manifestations of Salmonellosis in humans there are 4 syndromes are:
1. Gastroenteritis or food poisoning is an intestinal infection and toxin was not found previously (Karsinah et al, 1994). Happen by swallowing contaminated food with Salmonella sp. such as meat and eggs (Julius, 1990). Incubation period of 8-48 hours, the symptoms are nausea, headache, vomiting, severe diarrhea, and there is blood in the stool. Mild fever that will recover within 2-3 days. Bacteremia is rare in patients (2-4%) except in patients who lack immune (Jawezt et al, 2004).
2. Typhoid fever caused by S. typhi, and paratyphoid fever caused by S paratyphi A, B, and C. Germs that enter through the mouth into the stomach to reach the small intestine, and then to lymph nodes. Then enter the ductus thoracicus. Then the bacteria enter the blood stream (bacterimia) symptoms develop and up to the liver, spleen, bone marrow, kidney and others. Furthermore, in these organs Samonella sp. breed (Julius, 1990).
3. Bacteremia (septikimia) can be found in typhoid fever and non-typhi Salmonella infection. The presence of Salmonella in the blood at high risk of infection. Prominent symptom is hot and intermittent bacteremia (Karsinah et al, 1994). And local abnormalities arise in the body such as osteomyelitis, pneumonia, lung abscess, meningitis and others. This disease does not attack the intestines and stool culture negative (Julius, 1990).
4. Asomatik carrier that is all individuals infected with Salmonella sp. will islets germs in the feces for long periods of varying called convalesent carrier, if the patient is no longer 2-3 months islets Salmonella. And if in 1 year the patient was still islets of Salmonella called chronic carriers (Karsinah et al, 1994).
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