Salmonella (All Serotypes)

Salmonella are facultative anaerobic, motile gram-negative rods commonly isolated from the intestines of humans and animals. Identification is primarily based on the ability of the organism to use citrate as the sole carbon source and lysine as a nitrogen source in combination with hydrogen sulfide (H₂S) production. The genus is comprised of two primary species, S. enterica (human pathogen) and S. bongori (animal pathogen). S. enterica is subdivided into six subspecies: subsp. enterica, subsp. salamae, subsp. arizonae, subsp. diarizonae, subsp. houtenae, and subsp. indica. S. enterica subsp. enterica can be further divided into serotypes with unique virulence properties. Serotypes are differentiated based on the characterization of the heat-stable O antigen, included in the LPS, the heat-labile H antigen flagellar protein, and the heat-labile Vi antigen, capsular polysaccharide. A DNA sequence-based method has been developed for molecular identification of DNA motifs in the flagella and O antigens.

 Shigella spp. (S. dysenteriae, S. flexneri, S. boydii, S. sonnei)

 Shigella spp. are nonmotile; lysine decarboxylase–negative; citrate-, malonate-, and H₂S-negative; non–lactose fermenting; gram-negative rods that grow well on MacConkey agar. The four subgroups of Shigella spp. are: S. dysenteriae (group A), S. flexneri (group B), S. boydii(group C), and S. sonnei (group D). Each subgroup has several serotypes. Serotyping is based on the somatic LPS O antigen. After presumptive identification of a suspected Shigella species based on traditional biochemical methods, serotyping should be completed, especially in the case of S. dysenteriae. Suspected strains of Shigella sp. that cannot be typed by serologic methods should be referred to a reference laboratory for further testing.

Yersinia spp. (Y. pestis, Y. enterocolitica, Y. frederiksenii, Y. intermedia, Y. pseudotuberculosis)

Yersinia spp. are gram-negative; catalase-, oxidase-, and indole-positive, non–lactose fermenting; facultative anaerobes capable of growth at temperatures ranging from 4° to 43°C. The gram-negative rods exhibit an unusual bipolar staining. Based on the composition of the LPS in the outer membrane, colonies may present with either a rough form lacking the O-specific polysaccharide chain (Y. pestis) or a smooth form containing the lipid A-oligosaccharide core and the complete O-polysaccharide (Y. pseudotuberculosis and Y. enterocolitica). Complex typing systems exist to differentiate the various Yersinia spp., including standard biochemical methods coupled with biotyping, serotyping, bacteriophage typing, and anti biogram analysis. In addition, epidemiologic studies often include pulsed-field gel electrophoresis (PFGE) studies.

اخر الاخبار

اخبار العتبة العباسية المقدسة

قسم العلاقات العامة يختتم فعاليات محطات فتية الكفيل الثقافية في محافظة نينوى

ما الخدمات التي قدّمها موكب أشبال الطفّ لزائري عاشوراء؟

العتبة العباسية المقدسة تنظّم مسيرات عزائية لإحياء ذكرى عاشوراء في نينوى

قسم الشؤون الفكرية يحيي ذكرى استشهاد الإمام الحسين (عليه السلام) في القارة الإفريقية

المزيد

الآخبار الصحية

تناول الجبن.. مفيد للجسم أم خطر يهدد صحتك؟

طبيبة أسنان تحذر.. لا تتجاهل هذه العلامة بعد التنظيف

يجب أن تأكل المزيد من الشمام هذا الصيف.. إليك السبب ؟

تأثير صحي كبير.. كم بيضة يجب أن تتناول يوميا؟

المزيد

الآخبار التكنلوجية

أداء خلايا البيروفسكايت الشمسية تحت الماء قد يزيد كفاءة تحويل الكهرباء

مسافة الأمان: أساس القيادة الآمنة وتجنب الحوادث

هل القيادة السريعة تعني استهلاك اكثر للوقود؟

لماذا يعتبر كوكب المريخ غير صالح للحياة؟

المزيد

مواضيع ذات صلة

Cultivation of Enterobacteriaceae

Opportunistic Human Pathogens of Enterobacteriaceae

Vibrio

Salmonella

Escherichia coli

Laboratory Diagnosis for Nocardia, Streptomyces, Rhodococcus, and Similar Organisms

Epidemiology and Pathogenesis of Nocardia, Streptomyces, Rhodococcus, and Similar Organisms

General Characteristics of Nocardia, Streptomyces, Rhodococcus, and Similar Organisms

Pathogenesis of Streptococcus pneumoniae

Treatment and Prevention of Staphylococcus aureus

Pathogenesis of Staphylococcus aureus

Direct Detection Methods for Erysipelothrix, Lactobacillus, and Similar Organisms