​Kembara Xtra - Medicine - Salmonella Infection

​Kembara Xtra - Medicine - Salmonella Infection 
Any serotype of the gram-negative, facultatively anaerobic Salmonella bacteria can cause infection. Nontyphoidal Salmonella commonly causes gastroenteritis through foodborne infection and sporadic outbreaks; it less frequently causes infection outside the gastrointestinal (GI) tract.
- Nontyphoidal invasive illness - Enteric fever - Chronic carrier state (>1 year) - Nontyphoidal gastroenteritis
• Bacteremia-
 Endovascular problems
 Localized infection outside the gastrointestinal tract (such as osteomyelitis and abscesses)


Aspects of Geriatrics
Due to comorbidities (atherosclerotic endovascular lesions, prosthesis, etc.) that enhance the likelihood of bacterial seeding, patients over 65 have an increased risk of invasive illness with bacteremia and endovascular sequelae.


Child Safety Considerations
Infants under three months old are more vulnerable to invasive illness and consequences.

Epidemiology 
Incidence 
Global incidence of invasive nontyphoidal Salmonella infection estimated to be 535,000 cases in 2017.  Most frequently identified foodborne bacterial illness in the United States and a common cause of traveler's diarrhea.Global incidence of nontyphoidal Salmonella enteritidis estimated to be 94 million per year (mostly foodborne).Wide variation by region from 40 to 3,980 estimated cases per 100,000  Highest incidence of bacteremia in children under the age of five; hospitalization rates are higher in patients over the age of fifty; estimated 1.4 million cases annually in the United States; annual incidence of 15 illnesses per 100,000; peak frequency: July to November; second-most common bacteria isolated from stool cultures in diarrheal illness in the United States (behind Campylobacter); highest incidence of bacteremia in children under the age of five;


Pathophysiology and Etiology 
2,500 distinct serotypes of Salmonella enterica, the most virulent species in humans.
95% of cases are foodborne in terms of etiology.
- Additional cases (5%) are caused by direct or indirect oral contact with animal or human carriers who have the disease.
- Iatrogenic contamination, such as that caused by blood transfusion or endoscopy, is uncommon.


Pathophysiology - In immunocompetent patients, a typical infectious dosage is 1 million bacteria; however, this dose can be reduced in patients who are taking antibiotics or when there is a reduction in gastric acid.
- When bacteria are consumed, they infiltrate the proximal and distal colonic mucosa, triggering an inflammatory and cytotoxic reaction.
- Bacteria can cause invasive or disseminated illness by entering the mesenteric lymphatic system and later the systemic circulation.

Risk factors include recent travel to developing countries and the consumption of raw meat, raw eggs, and raw dairy products. Products made from non-animals have also been linked to epidemics.
Impaired gastric acidity is caused by H2 receptor blockers, antacids, proton pump inhibitors (PPIs), gastrectomy, achlorhydria, pernicious anemia, newborns, and contact with live reptiles or fowl.
Immunosuppression due to HIV, diabetes, corticosteroid or other immunosuppressant use, chemotherapy, recent antibiotic use, reticuloendothelial blockage from sickle cell disease, malaria, or bartonellosis, impaired phagocytic function from hemoglobinopathies, malaria, and chronic granulomatous illness.
 Age of 5 years or older.


Basic Prevention 

 Proper sanitation throughout food production, transportation, and storage (such as using refrigeration and fully boiling food before consumption); Control of animal reservoirs: Maintain good hand hygiene; the CDC monitoring outbreaks (http://www.cdc.gov/salmonella/); and stay away from high-risk animals, feces, and polluted rivers.

Accompanying Conditions 

Gastroenteritis, Bacteremia in immunocompromised individuals or individuals with underlying conditions (such as cholelithiasis, prosthesis), Osteomyelitis in people with sickle cell disease, Abscesses in people with malignant tumors, and Rheumatoid arthritis.

Salmonella infections are frequently asymptomatic or cause mild, self-limiting gastroenteritis. Exposure history includes travel, contact with sick people or animals, and faulty food preparation.
Age, immunological health, and other risk factors are considered hosts.
In most cases, symptoms appear 8 to 72 hours after intake and go away in 4 to 10 days.
Acute, simple disease with sudden onset of diarrhea that is not usually horrifyingly bloody but can be, especially in young individuals.
- Vomiting is not common.
- Cramps in the abdomen - Headache - Myalgias - Fever

Clinical Examination: Fever; Hypovolemic Signs; Tenderness in the Abdomen; Some Patients Have Heme-Positive Stool; Some Patients Have Hepatosplenomegaly


Differential diagnoses include pseudomembranous colitis, bacterial enteritis caused by other organisms, viral gastroenteritis, and inflammatory bowel disease.

Laboratory Results 

Initial examinations (lab, imaging)
Stool culture for Salmonella, Escherichia coli, Shigella, and Campylobacter in cases of gastroenteritis (the ideal specimen is a sample of diarrheal stools.)
- Stool cultures may be indicated for the following reasons:
 Serious diarrhoea (6 or more loose stools per day).Fever, bloody or mucous-filled diarrhea, many instances pointing to an outbreak, diarrhea lasting more than a week, and a positive fecal leukocyte test
- Blood cultures are recommended for anyone who exhibits indications of septicemia or other systemic manifestations of an infection, is under three months old, has a suspected case of enteric fever, or is immunocompromised.


Bacteremia may manifest as fever blood cultures and/or positive stool cultures.
If the patient is under three months old and has a positive blood culture, culture the CSF.
Endovascular infection: If an aortic or vascular cause is suspected in bacteremic patients older than 50 years old, consider angiography.
Consider CT or MRI for infections of soft tissue or bones. Local infections-Wound culture.
Chronic carriers may have positive urine cultures if their stool cultures have been positive for more than a year.


Further Tests 
When diarrhea lasts longer than 14 days, look for additional causes.
Salmonella excretion may continue asymptomatically for weeks after infection; hence, follow-up fecal cultures are ordinarily not advised for patients with simple gastroenteritis.
Blood cultures should be taken again if a patient has bacteremia.


Interpretation of Tests
If intestinal biopsies are performed, they may reveal reticuloendothelial hypertrophy/hyperplasia as well as mucosal ulceration, bleeding, and necrosis.


Management 
For immunocompetent individuals between the ages of 12 months and 50, the recommended course of treatment for nonsevere nontyphoidal Salmonella gastroenteritis is supportive care. Usually, the sickness has a limited lifespan. The value of treating minor illnesses has not been established. The immune response of the host can be suppressed by treatment. Additionally, higher relapse rates have been noted, and asymptomatic carriage may last longer.
In immunocompetent hosts who have severe diarrhea, a high fever, or who need hospitalization, take antibiotics into consideration.
● Antibiotics are beneficial for patients with bacteremia:
Patients >50 years old (Risk significantly rises after age 65) - Infants under 3 months - Patients under 3 months.


Patients with hemoglobinopathies, atherosclerotic lesions, prosthetic valves, grafts, or joints, as well as those who are immunosuppressed or have HIVSalmonella not typhoidal chronic carriage - 4 to 6 weeks of antibiotic therapy - Prophylactic treatment in immunocompromised people



 Hand washing and barrier precautions for inpatients.Hydration and electrolyte replacement.
When a patient has a fever or dysentery, antimotility medications should be avoided. Antimotility medications may prolong the time the enteropathogen is in touch with the gut mucosa.


First Line of Medicine
Uncomplicated gastroenteritis: Supportive care is all that is required; no special drugs are required. Complicated gastroenteritis (owing to sickness severity or host risk factors like immunosuppression)
– Adults (If immunocompromised, treat for 14 days.)
Levofloxacin: 500 mg once daily orally for one to three days.
Ciprofloxacin: 750 mg daily, orally, for one day; 500 mg daily, orally, for three days.
 400 mg/day, orally, for 1 to 3 days, of ofloxacin
 Azithromycin: 500 mg/day PO for 3 days, or 1 g, then 500 mg per day for 3 days.


Children's preferred treatment for febrile diarrhea or dysentery
.Ceftriaxone: two equally spaced doses of 100 mg/kg/day IV or IM for seven to ten days, or
 Azithromycin: 10 mg/kg/day for the following dosages over the course of seven days after the initial dose of 20 mg/kg PO.
AIDS patients
Increased antimicrobial therapy duration (between 2 and 6 weeks) and/or zidovudine use may reduce relapse.


Bacteremia: Due to trends in resistance, life-threatening infections in adults should be treated with fluoroquinolones or third-generation cephalosporins until susceptibilities are established.
– Adults
400 mg IV BID for 10 to 14 days of Ciprofloxacin (or another fluoroquinolone) +
Ceftriaxone: 1–2 g intravenously every day for 10–14 days, or
Children: Cefotaxime: 2 g IV every eight hours for 10 to 14 days
Trimethoprim-sulfamethoxazole: 8 to 12 mg/kg/day of the trimethoprim component in 2 divided doses for 10 to 14 days or Amoxicillin: 30 mg/kg/dose TID for 10 to 14 days
50 mg/kg/day (maximum 1 g) BID for 10 to 14 days of ceftriaxone
 Localized infection (such as pneumonia, cholangitis, osteomyelitis, and septic arthritis); surgical drainage or débridement in addition to at least three weeks of antibiotic treatment
- For 4 to 6 weeks, administer antibiotics orally to patients with immunocompromised patients, chronic local infections, or sustained bacteremia.


Chronic carrier status (shedding for more than a year)
Ciprofloxacin: 500 mg PO BID for 4 weeks; Levofloxacin: 500 mg/day for 4 weeks; Norfloxacin: 400 mg PO BID for 4 weeks if gallstones are present. Amoxicillin: 1 g PO TID for 12 weeks. Trimethoprim-sulfamethoxazole: 160 mg/800 mg PO BID for 12 weeks.

Caution 

Resistance to antibiotics
.There have been reports of strains that are resistant to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole.
Fluoroquinolone resistance is rising, possibly as a result of the drugs' expanding use in animals.
There have been more and more reports of extended-spectrum cephalosporin resistance.


Next Line
Aztreonam is an alternate medication that may be helpful for people who have several allergies or if the organism exhibits an unusual pattern of resistance.
Fluoroquinolones are currently frequently administered to kids for 5 to 7 days in regions of the world where Salmonella typhi is frequently multidrug resistant.


Surgical Procedures
If biliary tract disease is present, a preoperative 10- to 14-day course of parenteral antibiotics is advised prior to cholecystectomy. Surgical excision and drainage for contaminated tissue areas, followed by a minimum of 3 weeks of antibiotic therapy.

Patient Follow-Up Monitoring

Salmonella can shed asymptomatically for weeks after infection. Patients with simple gastroenteritis typically don't need follow-up fecal cultures. During a Salmonella outbreak, requirements might change.
 State and local laws may have different requirements. Some public health agencies demand negative stool cultures before allowing medical personnel and food handlers to resume their jobs. It can take 4 to 8 weeks to finish shedding.
Public health laboratories can perform serotyping on isolates.

Diet 

Simple to digest food

Modification of Lifestyle 

 Careful hand washing and handling of raw meat, poultry, and eggs
Before eating, fruits and vegetables should be well cleaned.
Salmonella is eliminated from meats by thorough cooking.
 Use caution while handling animals that have high incidences of fecal carriage. 


Salmonella gastroenteritis typically has a good prognosis and a self-limited course.
The elderly (>65 years), the immunocompromised, and the young (3 months) all have higher mortality rates.
Mortality is increased in multidrug-resistant strains, and is associated with bacteremia and other invasive infections.

Complications

Endocarditis, infectious endarteritis, meningitis, septic arthritis, reactive arthritis, osteomyelitis, pneumonia, appendicitis, cholecystitis, toxic megacolon, hypovolemic shock, metastatic abscess development

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