Salmonella

Infectious diseases

Clinicals - History

Fact Explanation
Diarrhea and passage of blood in the stool There are two categories of salmonella: non typhoid and typhoid salmonella. Nontyphoidal Salmonella are responsible for the foodborne diseases such as gastroenteritis. Salmonella typhimurium and Salmonella enteritidis are the main serotypes responsible for the disease. It is caused by eating raw or undercooked meat, poultry, eggs or egg products. Incubation period is 6-72 hours. Salmonella is a gram-negative, flagellated facultatively anaerobic bacilli with O, H, and Vi antigens. Bacteria passes through the stomach and reach the small and large intestine, then causes invasion of the intestine, production of endotoxins and release of cytokines with associated inflammation. Inflammation and damage to the intestinal mucosa causes increased exudates and reduced absorption of intestinal products leading to diarrhea and leakage of blood with stools. Diarrhoea can be defined as three or more loose stools in a 24-hour period. Diarrhea and passage of blood in the stool
There are two categories of salmonella: non typhoid and typhoid salmonella. Nontyphoidal Salmonella are responsible for the foodborne diseases such as gastroenteritis. Salmonella typhimurium and Salmonella enteritidis are the main serotypes responsible for the disease. It is caused by eating raw or undercooked meat, poultry, eggs or egg products. Incubation period is 6-72 hours. Salmonella is a gram-negative, flagellated facultatively anaerobic bacilli with O, H, and Vi antigens. Bacteria passes through the stomach and reach the small and large intestine, then causes invasion of the intestine, production of endotoxins and release of cytokines with associated inflammation. Inflammation and damage to the intestinal mucosa causes increased exudates and reduced absorption of intestinal products leading to diarrhea and leakage of blood with stools. Diarrhoea can be defined as three or more loose stools in a 24-hour period.
Fever They can develop acute fever after the exposure. Invasion of epithelial cells by bacteria lead to the release of cytokines during inflammation. These pyrogens responsible for the fever. Fever may last up to 3-7 days. Fever
They can develop acute fever after the exposure. Invasion of epithelial cells by bacteria lead to the release of cytokines during inflammation. These pyrogens responsible for the fever. Fever may last up to 3-7 days.
Nausea Vomiting Abdominal cramps Myalgia Headache Common associations with fever and diarrhoea. Endotoxins activate the serum complement system and responsible for lot of manifestations. Nausea Vomiting Abdominal cramps Myalgia Headache
Common associations with fever and diarrhoea. Endotoxins activate the serum complement system and responsible for lot of manifestations.
Exposure to contaminated materials Eating from restaurants, caterers, bakeries increase the risk of getting salmonella infection. Raw meat, poultry and seafood may be contaminated with feces while processing. Eggs produced by the infected animals may be infected with salmonella. Lack of proper hand washing practice is a major contributing factor. Exposure to contaminated materials
Eating from restaurants, caterers, bakeries increase the risk of getting salmonella infection. Raw meat, poultry and seafood may be contaminated with feces while processing. Eggs produced by the infected animals may be infected with salmonella. Lack of proper hand washing practice is a major contributing factor.
History of travelling Salmonella infection is more common in developing countries, where there is poor sanitation. History of travelling
Salmonella infection is more common in developing countries, where there is poor sanitation.
History of contact with the pets Pets like birds, dogs or reptiles are sometimes infected with salmonella. History of contact with the pets
Pets like birds, dogs or reptiles are sometimes infected with salmonella.
History of immunodefficisency Immunocompromised persons such as patients with malignancy, human immunodeficiency virus, diabetes, and long-term corticosteroid therapy are susceptible for these infections and its complications. History of immunodefficisency
Immunocompromised persons such as patients with malignancy, human immunodeficiency virus, diabetes, and long-term corticosteroid therapy are susceptible for these infections and its complications.
Past history of antibiotic use or gastrointestinal surgeries These can alter the endogenous bowel flora of the intestine. Past history of antibiotic use or gastrointestinal surgeries
These can alter the endogenous bowel flora of the intestine.
Past history of antacid and H2 blocker use Antacids and H2 blockers may reduce the gastric acidity and predispose to salmonella infection. Past history of antacid and H2 blocker use
Antacids and H2 blockers may reduce the gastric acidity and predispose to salmonella infection.
If complicated: bone pain, joint pain, confusion, Salmonella can cause bacteremia, if the bacteria gets disseminated from the intestines to systemic circulation. Then there is a possibility of focal infections such as septic arthritis, osteomyelitis, cholangitis, meningitis, and pneumonia. If complicated: bone pain, joint pain, confusion,
Salmonella can cause bacteremia, if the bacteria gets disseminated from the intestines to systemic circulation. Then there is a possibility of focal infections such as septic arthritis, osteomyelitis, cholangitis, meningitis, and pneumonia.
Drowsiness This may be either due to severe dehydration or meningitis like focal infections occurring as complications of the disease. Drowsiness
This may be either due to severe dehydration or meningitis like focal infections occurring as complications of the disease.

Clinicals - Examination

Fact Explanation
Febrile They can present with acute fever. Temperature may be 38°C to 39°C. Febrile
They can present with acute fever. Temperature may be 38°C to 39°C.
Sunkan eyes, dry skin, dry mucous membrane, reducde skin turger This is due to the reduced appetite, reduced fluid intake and increased loss of fluids via diarrhoea that result in dehydration. Sunkan eyes, dry skin, dry mucous membrane, reducde skin turger
This is due to the reduced appetite, reduced fluid intake and increased loss of fluids via diarrhoea that result in dehydration.
Low blood pressure May be due to dehydration and septic shock. Septic shock may be related to the production of endotoxins. Low blood pressure
May be due to dehydration and septic shock. Septic shock may be related to the production of endotoxins.
Bone and joint tenderness If complicated with osteomyelitis and arthritis. Bone and joint tenderness
If complicated with osteomyelitis and arthritis.
Altered mental state Due to severe dehydration or complications such as meningitis. Altered mental state
Due to severe dehydration or complications such as meningitis.

Investigations - Diagnosis

Fact Explanation
Stool culture This is the main mode of identification of the pathogen. MacConkey agar(MAC), Hektoen enteric agar or Xylose Lysine Desoxycholate Agar(XLD) are some of the mediums used to culture the organism. Salmonella produce colourless (lactose negative) colonies on MAC and clear to light pink colonies with distinct black centres on Hektoen enteric agar and XLD. Stool culture
This is the main mode of identification of the pathogen. MacConkey agar(MAC), Hektoen enteric agar or Xylose Lysine Desoxycholate Agar(XLD) are some of the mediums used to culture the organism. Salmonella produce colourless (lactose negative) colonies on MAC and clear to light pink colonies with distinct black centres on Hektoen enteric agar and XLD.
Blood culture May be positive on certain occasions. Blood culture
May be positive on certain occasions.
Stool full report Stool full report will show any evidence such as cysts, ova, amoeba, pus cells in the stools. Stool full report
Stool full report will show any evidence such as cysts, ova, amoeba, pus cells in the stools.
Food samples Food samples can be checked (if available) specially during an outbreak. Food samples
Food samples can be checked (if available) specially during an outbreak.

Investigations - Management

Fact Explanation
Serum electrolytes As there is loss of electrolytes during diarrhoea, it is important to monitor them to assess response to therapy. Serum electrolytes
As there is loss of electrolytes during diarrhoea, it is important to monitor them to assess response to therapy.
Full blood count They can have increased white cell count. As the patient is presenting with the fever, it is important to exclude the other conditions such as viral infections that can present with increased lymphocytes in the blood (lymphocytosis) and reduced platelets count. Pack cell volume may be increased in dehydration. Full blood count
They can have increased white cell count. As the patient is presenting with the fever, it is important to exclude the other conditions such as viral infections that can present with increased lymphocytes in the blood (lymphocytosis) and reduced platelets count. Pack cell volume may be increased in dehydration.
Serum electrolytes There can be hypokalaemia, hytponatraemia and hypochloraemia due to electrolyte loss. Serum electrolytes
There can be hypokalaemia, hytponatraemia and hypochloraemia due to electrolyte loss.
Computer tomography Salmonella can cause endarteritis, leading to aortic aneurysms. This is diagnosed preoperatively by the features of CT scan . Computer tomography
Salmonella can cause endarteritis, leading to aortic aneurysms. This is diagnosed preoperatively by the features of CT scan .
Blood cultures If the patient is having persistent fever, with clinical deterioration it is important to exclude the bacteremia by blood cultures. Blood cultures
If the patient is having persistent fever, with clinical deterioration it is important to exclude the bacteremia by blood cultures.
Serum electrolytes There can be electrolyte imbalances occur due to the loss of electrolytes. Serum electrolytes
There can be electrolyte imbalances occur due to the loss of electrolytes.

Management - Supportive

Fact Explanation
Controlling pain and fever Analgesics and antipyretics can be used to control the abdominal pain and fever. Better not to use non steroidal anti inflammatory drugs as there can be a risk of bleeding. Controlling pain and fever
Analgesics and antipyretics can be used to control the abdominal pain and fever. Better not to use non steroidal anti inflammatory drugs as there can be a risk of bleeding.
Controlling nausea and vomiting Antiemetics can be used. Controlling nausea and vomiting
Antiemetics can be used.
Antidiarrheals e.g loperamide Used only In mild diarrheas, it has a antimotility action that reduce stool frequency. But should not be used in severe diarrhea, as it can cause collection of large fluid volumes in bowel loops. Antidiarrheals e.g loperamide
Used only In mild diarrheas, it has a antimotility action that reduce stool frequency. But should not be used in severe diarrhea, as it can cause collection of large fluid volumes in bowel loops.
Prevention Good animal slaughtering practices to reduce contamination of animal products, protecting food from contamination, educating food-handling personnel in slaughterhouses, and restaurants on proper hygienic practices, using cooking food for consumption and proper surveillance system by the government are helpful in preventing the disease. Prevention
Good animal slaughtering practices to reduce contamination of animal products, protecting food from contamination, educating food-handling personnel in slaughterhouses, and restaurants on proper hygienic practices, using cooking food for consumption and proper surveillance system by the government are helpful in preventing the disease.
Vaccines Vaccines are only available for typhoid fever. No vaccines are available for non-typhoidal salmonella. Vaccines
Vaccines are only available for typhoid fever. No vaccines are available for non-typhoidal salmonella.
Probiotics Probiotics are live microbes that provides same action as
normal human gut microflora. Some of them are lactobacillus , bifidobacterium
and streptococcus. These will reduce the incidence of repetitive diarrhoea in children.
Probiotics
Probiotics are live microbes that provides same action as
normal human gut microflora. Some of them are lactobacillus , bifidobacterium
and streptococcus. These will reduce the incidence of repetitive diarrhoea in children.

Management - Specific

Fact Explanation
Rehydration Diarrhea may require oral rehydration, and if severe even intravenous fluids. Prevention and timely treatment of dehydration helps to prevent deaths due to diarrhoea. Oral rehydration solution with total osmolarity 311 mmol/l is the current recommendation by the world health organization. As there is loss of fluid and electrolytes during the diarrhoea there can be dehydration, hyponatraemia, hypokalaemia, and metabolic acidosis(due to bicarbonate loss). The glucose-sodium co-transporter is preserved in diarrhoeal diseases. Therefore if external solution can provides these electrolytes it can replace the loss. ORS contains sodium, potassium, chloride, citrate and glucose anhydrous in appropriate amounts. During the management of mild to moderate dehydration, rehydration requires 50-100ml/kg over 3-4 hours. Usually around 50 ml of ORS per each stool is required for the replacement. If there are features of overhydration such as swelling of eyelids, ORS should be temporarily stopped. Breast feeding should be continued during the episode. Severe cases need intravenous fluid replacement with 0.9% normal saline/ringer's lactate. Rehydration
Diarrhea may require oral rehydration, and if severe even intravenous fluids. Prevention and timely treatment of dehydration helps to prevent deaths due to diarrhoea. Oral rehydration solution with total osmolarity 311 mmol/l is the current recommendation by the world health organization. As there is loss of fluid and electrolytes during the diarrhoea there can be dehydration, hyponatraemia, hypokalaemia, and metabolic acidosis(due to bicarbonate loss). The glucose-sodium co-transporter is preserved in diarrhoeal diseases. Therefore if external solution can provides these electrolytes it can replace the loss. ORS contains sodium, potassium, chloride, citrate and glucose anhydrous in appropriate amounts. During the management of mild to moderate dehydration, rehydration requires 50-100ml/kg over 3-4 hours. Usually around 50 ml of ORS per each stool is required for the replacement. If there are features of overhydration such as swelling of eyelids, ORS should be temporarily stopped. Breast feeding should be continued during the episode. Severe cases need intravenous fluid replacement with 0.9% normal saline/ringer's lactate.
Antibiotic treatment Antimicrobial therapy is not recommended for uncomplicated gastroenteritis. It is recommended for who are severely ill, patients at increased risk of invasive spread of infection such as immunocompromised people and neonates <3 months of age.
Fluoroquinolones, trimethoprim-sulfamethoxazole, ampicillin or third-generation cephalosporins (e.g., ceftriaxone, or cefixime)are the suitable drugs to treat salmonella infection. Duration of treatment would be 3–7 days. Development of resistance to main antimicrobial agents is a problem in the current practice.
Antibiotic treatment
Antimicrobial therapy is not recommended for uncomplicated gastroenteritis. It is recommended for who are severely ill, patients at increased risk of invasive spread of infection such as immunocompromised people and neonates <3 months of age.
Fluoroquinolones, trimethoprim-sulfamethoxazole, ampicillin or third-generation cephalosporins (e.g., ceftriaxone, or cefixime)are the suitable drugs to treat salmonella infection. Duration of treatment would be 3–7 days. Development of resistance to main antimicrobial agents is a problem in the current practice.
Management of complications Bacteremia is usually treated using a single agent.(ampicillin or a third-generation cephalosporin or quinolone) Aneurysm due to endarteritis may need surgical care. Management of complications
Bacteremia is usually treated using a single agent.(ampicillin or a third-generation cephalosporin or quinolone) Aneurysm due to endarteritis may need surgical care.

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