Microbiology 10 - Gram Negative Anaerobic Rods General Characteristics of Enterobacteriaceae - Gram staining: pink o Depends on how they take up crystal violet - Has a thin peptidoglycan layer - Motile (flagella) - Non-sporulating - Facultative anaerobe o Respire aerobically but if conditions change, they can change to fermentation - Produce acid from glucose - Catalyse-positive - Oxidase-negative o They van produce cytochrome-c (enzyme) Salmonella History - 1885: Daniel Elmer Salmon o Something related to pigs - 1990: Joseph Leon Lignieres o Passed through a variety of different ways Nomenclature - 2600 different serotypes of salmonella - Can be split into o salmonella bongori o salmonella enterica · Sub. 1: enterica . Salmonella that causes typhoid fever · Non-typhoidal salmonella Extra intestinal infection " Can get into blood and cause a more serious infection o Gastroenteritis " Sub. 2: salamae " Sub. 3: arizonae Sub. 4: diarizonae Sub. 5: Hautenae Sub. 6: Indica - Naming is based on lipid polysaccharide structure (o-antigen) and their flagella (h- antigen) Typhoidal Salmonella - Incubation period of 8 - 14 days - Causes typhoid fever - Salmonella parathyroid; 1 - 10 days o Leads to parathyroid infection
- Spreads through ingestion - And then enters the bloodstream - Symptoms; fever, stomach upsets, headaches Characteristics of Salmonella - Gram negative - Diameter: 0.ff -1.5 um - Lengths: 2-5 um - Growth 5.5 -45.6 oC o Happy to grow in your gut pH o Long life span - Survive in water activity at 0.99 o Loads of dried/frozen food - Second leading cause of food born illness - 82000 cases - In developing countries, it's a lot higher - Notification pyramid: o Exposure to the general public is high o Some of them will get ill o Smaller of them will actually go to the GP o Even fewer will get specimens taken from them o Then reported to the CDC Epidemiology over the years - 1940s: - 1953-1954: o Lowest case numbers o People were on rations, not a lot of access to meant, and eggs etc o Morse animal slaughter o Salmonella cases increase - 1959s: o Surge linked to eating eggs - 1980s: - 1990s: o PT4 most prevalent serotype - linked to shell eggs o Edwina Currys: did a documentary that all eggs are covered in salmonella o 60% of sales decreased o Salmonella cases went down - 2002: o Introduced a vaccine to egg laying chicken o Provides them with immunity against salmonella o All eggs are stamped now
Animal Importation Slurry/Sewage Environmental pollution Slurry/Sewage Environmental pollution wildlife Farm Animals Human Food Man Imported Animal & Vegetable protein Products eaten by Animals Meat/Bone Meat Poultry Meat Major Routes Minor Routes Roles of Wildlife Pets Offal Imported foods Signs & Symptoms - Start appearing 12-ff2 hours - Some individuals its mild; o Fever o Diarrhoea - Can get bad and can spread into the blood stream o Stays there for a long time today o Cases where it was in the