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− | <big><center>[[Enterobacteriaceae|'''BACK TO ENTEROBACTERIACEAE''']]</center></big>
| + | Salmonella spp. are gram-negative straight rods, usually flagellated, facultative anaerobes. |
− | <big><center>[[Bacteria|'''BACK TO BACTERIA''']]</center></big>
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− | <big><center>[[Infectious agents and parasites|'''BACK TO INFECTIOUS AGENTS AND PARASITES''']]</center></big>
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| ===Overview=== | | ===Overview=== |
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| *Most motile with flagellae (H antigen) | | *Most motile with flagellae (H antigen) |
| *H antigen can be in phase 1 or phase 2, depending on a genetic switch allowing for one of the H antigen genes to be transcribed at any one time | | *H antigen can be in phase 1 or phase 2, depending on a genetic switch allowing for one of the H antigen genes to be transcribed at any one time |
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| ===Classification=== | | ===Classification=== |
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| **Stimulate immune response on reaching the lamina propria | | **Stimulate immune response on reaching the lamina propria |
| **Acute inflammation, possibly with ulceration; prostaglandin and cytokine production by epithelial cells; enterotoxin production damaging mucosa | | **Acute inflammation, possibly with ulceration; prostaglandin and cytokine production by epithelial cells; enterotoxin production damaging mucosa |
− | **Phagocytosis of bacteria by neutrophils and macrophages | + | **Phagocytosis of bacteria by [[Neutrophils|neutrophils]] and macrophages |
| **Bacteria either destroyed by the phagocytic cells or survive and multiply in the cells to cause systemic disease | | **Bacteria either destroyed by the phagocytic cells or survive and multiply in the cells to cause systemic disease |
| **Resistance to phagocytosis and destruction by complement allows spread within the body - bacteraemia and septicaemia | | **Resistance to phagocytosis and destruction by complement allows spread within the body - bacteraemia and septicaemia |
| **LPS O antigens prevent damage to bacterial cell wall by complement | | **LPS O antigens prevent damage to bacterial cell wall by complement |
| **LPS also causes endotoxaemia, and may contribute to local inflammatory response damaging intestinal cells to cause diarrhoea | | **LPS also causes endotoxaemia, and may contribute to local inflammatory response damaging intestinal cells to cause diarrhoea |
− | **Endotoxic shock during septicaemic salmonellosis due to LPS | + | **Endotoxic shock during septicaemic [[Salmonellosis|salmonellosis]] due to LPS |
| + | **Septicaemia may cause [[Bacterial skin infections - Pathology#Systemic bacterial infections|cyanosis of extremities]] |
| **Intracellular carriage if bacteria no completely removed | | **Intracellular carriage if bacteria no completely removed |
− | **Invasive potential of certain strains e.e ''Salmonella'' Dublin associated with carriage of a large plasmid, encoding genes to allow intracellular survival in macrophages and also to allow iron acquisition | + | **Invasive potential of certain strains e.g. ''Salmonella'' Dublin associated with carriage of a large plasmid, encoding genes to allow intracellular survival in macrophages and also to allow iron acquisition |
| **''Salmonellae'' are facultative intracellular organisms, allowing them to move from the gut in macrophages and cause a bacteraemia and lesions throughout the body | | **''Salmonellae'' are facultative intracellular organisms, allowing them to move from the gut in macrophages and cause a bacteraemia and lesions throughout the body |
| **Possession of Pathogenicity Islands associated with virulence | | **Possession of Pathogenicity Islands associated with virulence |
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| **Bacteria can survive intracellularly, avoiding the immune system and antimicrobials | | **Bacteria can survive intracellularly, avoiding the immune system and antimicrobials |
| **May have latent carriage and intermittent excretion in faeces | | **May have latent carriage and intermittent excretion in faeces |
− | **Stresses e.g. transportaion, illness, parturition, overcrowding promote excretion in carrier animals and may cause clinical signs to be shown | + | **Stresses e.g. transportation, illness, parturition, overcrowding promote excretion in carrier animals and may cause clinical signs to be shown |
| **Tortoises, terrapins, snakes and other reptiles ofter carry ''Salmonellae'' | | **Tortoises, terrapins, snakes and other reptiles ofter carry ''Salmonellae'' |
− | **Asymptomatic carriage allows faecal spread of infection | + | **Asymptomatic carriage allows faecal spread of infection |
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| ===Clinical infections=== | | ===Clinical infections=== |
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| *Zoonotic | | *Zoonotic |
− | *Outbreaks from contaminated imported meat and bone meal | + | *Most human infections contracted from animals, especially poulty and cattle |
| *Some serotypes are host-specific, some infect a wide range of species | | *Some serotypes are host-specific, some infect a wide range of species |
− | *Healthy adult carnivores are resistant to salmonellosis | + | *Healthy adult carnivores are resistant to [[Salmonellosis|salmonellosis]] |
| *Clinical outcome depends on number of bacteria ingested, virulence of serotype, susceptibility of host | | *Clinical outcome depends on number of bacteria ingested, virulence of serotype, susceptibility of host |
| *Young and debilitated animals susceptible | | *Young and debilitated animals susceptible |
| *''Salmonella'' serotypes: | | *''Salmonella'' serotypes: |
− | **''S.'' Tymphimurium infects many species; causes severe diarrhoea; non-invasive; causes of food poisoning in humans, e.g. from infected poultry | + | **''S.'' Typhimurium infects many species; causes severe diarrhoea; non-invasive; causes of food poisoning in humans, e.g. from infected poultry |
| **''S. enteritidis'': non species-specific; losses in young birds; causes food poisoning in humans | | **''S. enteritidis'': non species-specific; losses in young birds; causes food poisoning in humans |
| **''S.'' Dublin: invasive serovar; infects cattle | | **''S.'' Dublin: invasive serovar; infects cattle |
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| **''S.'' Abortus-equi: infects horses outside of the UK | | **''S.'' Abortus-equi: infects horses outside of the UK |
| **''S.'' Typhi, ''S.'' Paratyphi: infect humans | | **''S.'' Typhi, ''S.'' Paratyphi: infect humans |
− | *Most human infections contracted from animals, especially poulty and cattle | + | **''S.'' Montevideo produces outbreaks from contaminated imported meat and bone meal |
− | *Enteric salmonellosis: | + | *Enteric [[Salmonellosis|salmonellosis]]: |
| **Enterocolitis occurs in most farm animal species affecting all ages | | **Enterocolitis occurs in most farm animal species affecting all ages |
− | **[[Intestines - Ulcerative Enteritis|ulcerative enteritis]] | + | **[[:Category:Enteritis, Ulcerative|Ulcerative enteritis]] |
| **Fever, depression, anorexia, foul-smelling diarrhoea containing blood, mucus and epithelial casts | | **Fever, depression, anorexia, foul-smelling diarrhoea containing blood, mucus and epithelial casts |
| **Dehydration and weight loss | | **Dehydration and weight loss |
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| **Milder syndrome where endemic on farms, possibly due to acquired immunity | | **Milder syndrome where endemic on farms, possibly due to acquired immunity |
| **Chronic enterocolitis can occur in surviving pigs, cattle, horses, causing intermittent fever, soft faeces and gradual weight loss | | **Chronic enterocolitis can occur in surviving pigs, cattle, horses, causing intermittent fever, soft faeces and gradual weight loss |
− | *Septicaemic salmonellosis: | + | *Septicaemic [[Salmonellosis|salmonellosis]]: |
| **Most common in calves, neonatal foals, pigs under one month | | **Most common in calves, neonatal foals, pigs under one month |
| **Sudden onset fever, depression, recumbency | | **Sudden onset fever, depression, recumbency |
| **Die within 48 hours if not treated | | **Die within 48 hours if not treated |
| **Persistent diarrhoea, meningitis, arthritis or pneumonia may occur in surviving animals | | **Persistent diarrhoea, meningitis, arthritis or pneumonia may occur in surviving animals |
− | **Can cause in [[Bones - inflammatory#Osteomyelitis|Osteomyelitis]]
| + | **Found in [[Infectious Arthritis#In Horses|arthritis of horses]] |
− | **Found in [[Joints - inflammatory#In Horses|arthritis of horses]] | + | **Can cause haemorrhagic disease by [[Platelet Abnormalities|secondary thrombocytopenic disease]] |
− | **Can cause haemorrhagic disease by [[General Pathology - Haemostasis#Secondary Thrombocytopenic Disease|secondary thrombocytopenic disease]] | |
| **''S.'' Cholerae-Suis in pigs causes blue discoloration of ears and snout; co-infection with viruses causes severe clinical forms of disease | | **''S.'' Cholerae-Suis in pigs causes blue discoloration of ears and snout; co-infection with viruses causes severe clinical forms of disease |
− | *Bovine [[Intestines - Fibrinous/ Haemorrhagic Enteritis#Salmonellosis|Salmonellosis]]: | + | *Bovine [[Salmonellosis|salmonellosis]]: |
| **Syndrome of fever and diarrhoea (with dysentery), often fatal, in calves and adult cattle | | **Syndrome of fever and diarrhoea (with dysentery), often fatal, in calves and adult cattle |
| + | **Abdominal pain in adult cattle due to necrotic bowel |
| + | **Recumbency and depression, with death after 7-10 days during severe infection - mortality up to 75% in untreated adult animals |
| + | **Antibiotic treatment reduces mortality to 10% |
| + | **Diarrhoea lasts for up to 2 weeks, and complete recovery may take months |
| **May cause abortion of pregnant cattle in absence of other signs | | **May cause abortion of pregnant cattle in absence of other signs |
| **Septicaemia in neonates; accute enteritis in older calves | | **Septicaemia in neonates; accute enteritis in older calves |
| + | **Calves are dull, lethargic, inappetent, pyrexic, with profuse, fowl-smelling diarrhoea |
| + | **Death in calves can occur after 2-3 days |
| + | **Diarrhoea in survivors may last 2 weeks |
| **Caused by infection with various ''Salmonella'' serotypes, e.g. ''S.'' Dublin and ''S.'' Typhimurium | | **Caused by infection with various ''Salmonella'' serotypes, e.g. ''S.'' Dublin and ''S.'' Typhimurium |
− | **Chronic infections with ''S.'' Dublin in calves cause dry gangrene and bone lesions
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| **An important zoonosis and reportable | | **An important zoonosis and reportable |
| **Carrier animals important for spread | | **Carrier animals important for spread |
− | *Salmonellosis in poultry: | + | **''Salmonella'' Dublin: |
| + | ***Causes enterocolitis with blood-stained, foul-smelling diarrhoea containing mucus and epithelial cells |
| + | ***Can cause fatal septicaemia - fever, depression, drop in milk yield; calves may develope arthritis, meningitis, pneumonia |
| + | ***Abortion with no other clinical signs |
| + | ***Chronic infections with ''S.'' Dublin in calves cause dry gangrene of extremities due to disseminated intravascular coagulation; tips of ears, tail and limbs may slough |
| + | ***Can cause [[Osteomyelitis|Osteomyelitis]] in young animals |
| + | ***Most survivors become subclinical excretors |
| + | ***May become latent carriers with no excretion |
| + | *<div id="Spleen">[[Salmonellosis|Salmonellosis]] in poultry: |
| **''S.'' Pullorum and ''S.'' Gallinarum now rare in UK due to eradication programs including the Pullorum test (whole blood slide agglutination to detect antibody to both ''S.'' Pullorum and ''S'' Gallinarum) | | **''S.'' Pullorum and ''S.'' Gallinarum now rare in UK due to eradication programs including the Pullorum test (whole blood slide agglutination to detect antibody to both ''S.'' Pullorum and ''S'' Gallinarum) |
| **These ''Salmonellae'' can infect the ovaries of hens and be transmitted via eggs | | **These ''Salmonellae'' can infect the ovaries of hens and be transmitted via eggs |
− | **Pullorum disease infects young chickens and turkeys (under 3 weeks); high mortality rates; anorexia, depression, white diarrhoea; white nodules throughout lungs; focal necrosis of liver and spleen | + | **Pullorum disease infects young chickens and turkeys (under 3 weeks); high mortality rates; anorexia, depression, white diarrhoea; white nodules throughout lungs; focal necrosis of liver and [[Spleen - Anatomy & Physiology|spleen]]</div> |
− | **Fowl typhoid causes similar lesions to pullorum disease in young birds; septicaemic condition in adult birds with sudden death (enlarged, friable, bole-stained liver and enlarged spleen) | + | **Fowl typhoid causes similar lesions to pullorum disease in young birds; septicaemic condition in adult birds with sudden death (enlarged, friable, bole-stained liver and enlarged [[Spleen - Anatomy & Physiology|spleen]]). On post mortem inspection bronzing of the organs is notable. |
| **Paratyphoid caused by non host-specific ''Salmonella'' serotypes, e.g. ''S.'' Enteritidis and ''S.'' Typhimurium; often subclinical infections | | **Paratyphoid caused by non host-specific ''Salmonella'' serotypes, e.g. ''S.'' Enteritidis and ''S.'' Typhimurium; often subclinical infections |
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| ===Diagnosis=== | | ===Diagnosis=== |
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| *Attenuated live ''S.'' Typhimurium and ''S.'' Dublin vaccines used in cattle | | *Attenuated live ''S.'' Typhimurium and ''S.'' Dublin vaccines used in cattle |
| *Avoid oral prophylactic antimicrobials | | *Avoid oral prophylactic antimicrobials |
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| + | ==In Reptiles== |
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| + | It is estimated that between 36 and 77% lizards harbour Salmonella - the most recognized reptilian zoonosis. Owners must be educated regarding the public health hazard (especially for the very young, the old and the immune compromised). |
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| + | [[Category:Lizard_and_Snake_Glossary]] |
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| + | [[Category:Enterobacteriaceae]] |
| + | [[Category:Zoonoses]] |
| + | [[Category:To_Do_-_Bacteria]] |