Question

A 7-year-old male presented to the emergency department with a 5-day history of 39 °C fever with vomiting. Over the last three days he had abdominal pain with non-bloody diarrhea. A blood culture grew Gram-negative rods, which were non-fermenters of lactose on MacConkey plates and indicated H₂S production on TSI slants, highly suggestive of non-typhoidal Salmonella infection.

His past history was significant: he helped his neighbor with his chickens for the past several weeks, and he had also been exposed to a variety of reptiles in the area near his home.

1. How did this patient likely become infected?

2. Explain how this organism can result in bacteremia, describe how the immune response is involved.
3. Does this type of infection require antibiotic treatment? What could be indicated?

4. Epidemiology:
   1. how is this organism transmitted to humans?
   2. Is this a low-or a high-dose pathogen?
   3. what are the populations at risk?

Answer 1

The patient got the infection via feco oral transmission. He may have taken some food without properly washing his hands.

After ingested, salmonella easily passes gastric juices and barriers, and invade mucosa of the small and large intestine and produces toxins. As soon as it invades the epithelial layer, a stimulation of proinflammatory cytokines take place which in turn produce inflammatory reactions.

Yes antibiotic treatment is necessary. Antibiotics such as flouroquinolons are given to adults and Azithromycin given to children. Ceftriaxone is an alternate first line drug.

Epidemiology:- This organism is transmitted to humans via feco oral route. It is a high dose pathogen. It requires 10⁶ bacteria to cause infection. The population living in poorly Sanitarised area such as slums are the worst affected.