Salmonellosis

1. {
Salmonellosis
Lecture for 5-th year
students

2. Lecture objectives
1. Be able to describe the salmonella
nomenclature system
2. Describe the epidemiology of non-typhoidal
salmonellosis (NTS)
3. Explain the path physiology and clinical
manifestations of NTS
4. Know the laboratory diagnosis, principles of
management and prevention of NTS

3.  Is a wide spectrum of disease, caused by bacteria of the
Enterobacteriaceae family, genus Salmonella. Agents are
highly adapted for growth in both humans and animals.
 The growth of serotypes S. Typhi and S. Paratyphi is
restricted to human hosts, in whom these organisms
cause enteric (typhoid) fever.
 The remaining serotypes (non typhoidal Salmonella, or
NTS) can colonize the gastrointestinal tracts of a broad
range of animals, including mammals, reptiles, birds, and
insects. More than 200 serotypes are pathogenic to
humans, and can be associated with localized infections
and/or bacteremia.
Salmonellosis

4. Family: Enterobacteriaceae
Genus: Salmonella
Species: S. enterica
S. bongori
Subspecies: I, II, IIIa, IIIb, IV, VI, VII (7)
Serovars: >2500 serotypes according to the somatic O antigen
[lipopolysaccharide (LPS) cell-wall components], the surface
Vi antigen (restricted to S. Typhi and S. Paratyphi C), and the
flagellar H antigen
S. enterica subspecies I includes serovar Typhi and Paratyphi
serovars A, B, and C, pathogenic for humans.
All other serotypes are named nontyphoidal Salmonella (NTS)
Salmonella nomenclature system

5. NTS: salmonella speacies

6.  2.8 billion cases of diarrheal
illnesses each year worldwide
 incidence of diarrheal disease
ranged from 0.44 to 0.99 episodes per person-year
 93.8 million cases of gastroenteritis due
to Salmonella species occur globally each year (mostly
– foodborne), with 155 000 deaths
 Salmonella infection represents a considerable burden
in both developing and developed countries Efforts
to reduce transmission of salmonellae by food and
other routes must be implemented on a global scale.
NTS: distribution

7.  Salmonella is a ubiquitous and hardy bacteria that
can survive several weeks in a dry environment
and several months in water.
 Salmonella may be killed by
 60˚C for 15 minutes
 55˚C for 1 hour
 Boiling, chlorination,
pasteurization
Resistance of salmonella

8.  Group of intestinal infectious diseases
 NTS can be acquired from multiple animal
reservoirs.
 Animal food products: eggs, poultry, undercooked
ground meat, dairy products, and fresh produce
contaminated with animal waste.
 Centralization of food processing
and widespread food distribution
have contributed to the increased
incidence of NTS in developed
countries.
NTS: epidemiology

10.  Peanut butter; milk products,
including infant formula; and
snack foods; fresh produce,
including alfalfa sprouts,
cantaloupe, fresh-squeezed
orange juice, and tomatoes
 An estimated 6% of sporadic NTS
infections are attributed to
contact with reptiles
and amphibians (iguanas, snakes,
turtles, and lizards)
 Other pets: african hedgehogs
birds, rodents, baby chicks,
ducklings, dogs, cats, are also
potential sources of NTS.
NTS: epidemiology

11.  In contrast to enteric fever NTS gastroenteritis is
characterized by massive polymorphonuclear
leukocyte infiltration into both the large- and
small-bowel mucosa.
 This response appears to depend on the induction of
IL 8, a strong neutrophil chemotactic factor, which is
secreted by intestinal cells as a result of Salmonella
colonization and translocation of bacterial proteins
into host cell cytoplasm.
 The degranulation and release of toxic substances by
neutrophils may result in damage to the intestinal
mucosa, causing the inflammatory diarrhea
observed with non-typhoidal gastroenteritis.
NTS: path physiology

12.  A01 Typhoid and paratyphoid fevers
 A02 Other salmonella infections
 A02.0 Salmonella enteritis ( 72-97%)
 A02.1 Salmonella sepsis (2-8%)
 A02.2 Localized salmonella infections (5-10%)
 Salmonella: arthritis
 meningitis
 osteomyelitis
 pneumonia
 renal tubulo-interstitial disease
 A02.8 Other specified salmonella infections
 A02.9 Salmonella infection, unspecified
Classification ICD-10 (2016)

13.  Incubation period: 2- 6h –24-72h
 Acute, sudden onset, rapid course, illness
lasts 2–7 days.
 Fever (38–39°C; 100.5–102.2°F),
singes of general intoxication
 Stomach ache, preferably – around the nail and in right low
area of abdomen, diarrhea with a stinking, liquid stool of
greenish color, nausea and sometimes vomiting, sines of
dehydration.
 Symptoms are relatively mild and patients recover without
specific treatment in most cases. In the young, the elderly,
and patients with weakened immunity the associated
dehydration can become severe and life-threatening.
NTS: Manifestations

14.  Gastroenteritis caused by NTS is usually self-limited.
 Diarrhea resolves within 3–7 days and fever within 72 h.
 Stool cultures remain positive for 4–5 weeks after
infection and—in rare cases of chronic carriage (<1%)—
for >1 year.
 The most common
complications:
 Dehydration shock
 Toxic shock
 Acute renal failure
Salmonella enteritis: Clinical
Manifestations

15.  Dehydration shock, kidney failure
 Bacteremia. Approximately 5-8% of individuals
with NTS gastrointestinal illnesses
 Cardiovascular: Endocarditis, pericarditis, valve
perforation, and arteritis
 CNS infection: Meningitis, ventriculitis, abscess
 Pulmonary: Pneumonia, abscess, empyema, and
bronchopleural fistula
 Bone/joints: Septic arthritis and osteomyelitis
 Splenic, renal, genital, soft tissue abscesses may
occur.
Complications

16. 1) mild,
2) moderate
3) severe
Stages of dehydration (WHO):

17.  None or mild, but diarrhea: <5% loss of total body weight.
Thirst in some cases
 Moderate: 5–10% loss of total body weight. Thirst, postural
hypotension, weakness, tiredness, tachycardia, dry
mouth/tongue, few or no tears, decreased urine output,
dizziness, silent voice, dry pale skin
 Severe: >10% loss of total body weight. Lethargy, or
floppiness; weak or absent pulse, low blood pressure;
inability to drink;
sunken eyes (and,
in infants, sunken
fontanelles); no urine
decreased skin
turgor, seizure
Degree of Dehydration (WHO)

18.  Epidemiological history
 Clinical presentations
 CBC: leukocytosis, left
shift, increased ECR
 Urine analysis
 Coprogram
 Biochemistry: urea, creatinine, glucose, electrolytes,
acid balance
 Monitoring: fluid balance and diuresis (in severe
patients - hourly diuresis), BP, CVP, SpO2
 ECG, Ultrasound of abdomen
NTS: diagnosis

19.  Stool culture
 Blood culture
 Serological methods: indirect
hem-agglutination test for specific
antibodies in repeated
examinations or ELISA, EIA, RIA
for specific IgM
 Rapid tests
(immunochromatographic
technology, and molecular
techniques such as DNA
hybridization and PCR-based
assays
Specific Diagnosis

20.  Fluid and electrolyte replacement
 Routine antimicrobial therapy is not
recommended for mild or moderate cases in
healthy individuals
 This is because antimicrobials may not
completely eliminate the bacteria and may
select for resistant strains, which subsequently
can lead to the drug becoming ineffective.
 Antibiotics be reserved for patients with severe
disease or patients who are at a high risk for
invasive disease.
Treatment

21.  ORS (oral rehydration solution)
 absence of vomiting
 excluding of diabetes mellitus
 mild/moderate severe dehydration
 IV fluid replacement solutions (Ringer’s lactate
with additional potassium supplements)
 severely dehydrated patients
 vomiting independent on stage of dehydration
 diabetic patients
Rehydration therapy

22.  total fluid deficit can be replace safely
within the first 4 hours, half within the 1-t
hour
 30-40ml/kg – in mild dehydration
 50 ml/kg – in moderate severe dehydration
 100 ml/kg – in severe dehydration
Primary rehydration

23. Na+ – 90 mmol/l
K+ + – 20 mmol/l
Cl- – 80 mmol/l
Citrate – 10mmol/l
Glucosae – 110 mmol/l
Composition of WHO ORS

24.  Reduce bacterial contamination of animal-derived
food products
 Improve food-safety education and training
 Monitoring of every step of food production
 Contaminated food can be made safe for
consumption by pasteurization, irradiation,
or proper cooking.
 Routine hygienic measures
may prevent contact way
of transmission
NTS: prevention