1. Morning Report: Thursday, January 12th
Welcome APPLICANTS!

2. Shigella Infection

3. Epidemiology
Common cause of bacterial diarrhea worldwide (especially in developing countries)
In the US:
Third in frequency (after Salmonella and Campylobacter)
Primarily affects children
Peak incidence ages 1-4
165 million cases occur worldwide annually, 1 million associated deaths; 70% of the cases and 60% of the deaths involve children <5yo

4. The Details… Gram-negative bacilli Four species: S. dysenteriae
S. boydii
S. flexneri
S. sonnei
Only Shiga toxin-producing species!
Most common subtypes in the US
Shiga toxin produced most commonly by S. dysenteriae, and enterhemorrhagic E.coli

5. Transmission *Person-to-person via the fecal-oral route
Transmission in institutions
*Child care centers
Grouping of susceptible children
Lack of adherence to hand-washing procedures
Small inoculum required for disease production
Food borne transmission
Cold salads
Raw veggies
Sexual transmission
Inoculum: ingestion of as few as 10 organisms can cause illness

6. Clinical Presentation
Incubation period 1-7 days, average 3 days
Range of GI illness
Mild diarrhea life-threatening dysentary

7. Clinical Presentation
Course
Presentation: abrupt onset of high fever, generalized toxicity, crampy abdominal pain*, high-volume, watery stools
24-48h later: Small-volume, bloody, mucoid stools* with tenesmus
Neurologic manifestations (40%)
Severe HA
Seizures
Meningeal signs
Lethargy
Delirium/ hallucinations
Can also see emesis in 35%

8. Physical Exam VS: high fever (>102F) Gen: toxic-appearing
Abd: lower quadrant abdominal pain, distension
GU: tenderness on rectal exam
+/- signs of dehydration

9. Laboratory Findings Bandemia Stool microscopy Stool culture
Large number of PMNs
+/- RBCs
Stool culture
Send stool specimen promptly to lab
Can be grown on MacConkey or Hektoen-Enteric agars
Always want speciation and sensitivities
Largely clinical diagnosis where the labs are confirmatory

10. *Treatment Mainstay= SUPPORTIVE CARE!
Correction of fluid and electrolyte losses
Substantial volume depletion uncommon
Hyponatremia
NO intestinal antimotility drugs
Early restoration of oral intake

11. *Treatment Antibiotics
Lead to improvement in symptoms and decreased spread of infection to contacts
The problem…increasing antimicrobial resistance!!
Ampicillin
TMP-SMX
So, who do I treat and what do I use to treat them?

12. *Treatment Who to treat? Red Book Severe disease
Underlying immunosuppressive conditions
Dysentery
In mild cases Rx to prevent spread of the organism
Most infections with Shigella are self-limited and resolve within 48-72h (7d) without antimicrobial therapy

13. *Treatment What to use? Parenteral Oral Ceftriaxone Cipro Azithromycin
First-line oral Rx for children <18yo when Abx susceptibility is unknown
Fluoroquinolones
First-line oral Rx for children >17yo and adults

14. *Treatment What to use? Oral Cefixime Ampicillin or TMP-SMX
Alternative to azithromycin in children <18yo
Ampicillin or TMP-SMX
Only if sensitivities are known
5 day treatment regimen

15. Control Measures
Most importantly….
METICULOUS HAND HYGIENE!!!

16. Control Measures Hospital *Day care Contact precautions
Notify local health department
Stool cultures should be performed on all symptomatic attendees and staff
Affected persons should be excluded until:
Initiation of appropriate ABx
≥24 hours after diarrhea has resolved
Stool cultures are negative for Shigella
General: use of safe drinking water

17. Complications Intestinal Proctitis or rectal prolapse Toxic megacolon
Intestinal obstruction
Colonic perforation
Bacteremia: leukocytosis, hypothermia, T>39.5, severe dehydration, lethargy; occurs commonly in children <5

18. Complications Systemic Bacteremia Metabolic disturbances
Leukemoid reaction
Neurologic disease
Reactive arthritis
Alone or in association with conjunctivitis and urethritis (Reiter syndrome)
Hemolytic-uremic syndrome
Caused by EHEC (O157:H7), S. dysenteriae

19. A Question…
A previously healthy 3 ½ yo girl presents following 2 days of diarrhea, vomiting, and low-grade fever. Her symptoms began shortly after the family dined at a local fast-food restaurant. She has had 4-6 watery, mucoid stools per day. Her parents are very concerned because the have started to see some blood in her stool. On PE, the alert, somewhat irritable child has a T 38.6C, HR 100, RR 16. Her oral MM are dry. CRT~2 secs. Her abdomen is diffusely tender without distension. Labs show HgB 11.5, WBC 14.5, Na 136, K 4.5, Bicarb 18. Of the following, which is the most appropriate treatment?
A. A glucose-electrolyte solution
B. Cholestyramine
C. Loperamide
D. Metronidazole
E. TMP-SMX

20. A Question…
A 5yo girl presents after having a brief generalized seizure. Her mother reports that the child has had a 3 day h/o fever, tenesmus, and bloody diarrhea. On PE, you find a mildly toxic-appearing child who has a T104F and diffuse abdominal tenderness. The rectal exam produces significant pain. Stool from her rectum is guaiac-positive. You tell the mother that you believe the diarrhea has an infectious cause. Of the following, the MOST likely pathogen is:
A. Cryptosporidium sp
B. Rotavirus
C. Salmonella sp
D. Shigella sp
E. Yersinia sp

21. A Question…
You are evaluating a 2 yo boy with a 10h history of a temperature of 40.0C and progressively worsening diarrhea. Yesterday he attended a birthday party at the petting zoo, but he had no other history of ill contacts or unusual exposures. His mother states that he has had 8 watery bowel movements with mucus and streaks of blood in the last 10h. On PE, the boy is irritable and has a temp of 39.5C. His MM are slightly tacky, and his abdomen is diffusely TTP. The rest of the PE is normal. Labs show WBC 16.0 with 65% neutrophils and 9% bands. Microscopic exam of the stool shows fecal leukocytes, blood and mucus. Of the following, the MOST likely etiologic agent for this patient’s condition is
A. Campylobacter
B. E. Coli
C. Salmonella
D. Shigella
E. Yersinia enterocolitica

22. Infectious Diarrhea Symptoms Labs Treatment Salmonella Shigella
Transmission
Symptoms
Labs
Treatment
Salmonella
Chicken, milk, eggs; exotic pets (reptiles)
Fever, diarrhea with blood/ mucous
High WBC with left shift, +stool WBC, RBC (?+ BCx)
None with uncomplicated GE; at risk* Amoxil, Bactrim
Shigella
Person-to person; daycare! Fresh fruits and veges
Fever, abd. pain, watery diarrhea that becomes bloody, szs
High WBC and band ct, +stool WBC, RBC
Azithromycin, quinolones
Campylobacter
jejuni
Undercooked poultry or meat
Fever, abd pain, diarrhea with blood, vomiting
+stool WBC, RBC; Cx with chocolate agar
Erythromycin
E.Coli O157:H7
Undercooked beef, unpasturized milk
+stool WBC, RBC; look for signs of HUS
Abx not indicated! (increases risk for HUS)
Yersinia
enterocolitica
Pork (chitterlings)
Dysenteric syndrome, can mimic appy/ Crohns
+stool WBC, RBC
Bactrim, aminoglycosides, cephalosporins (3rd), quinolones
Clostridium
difficile
ABx exposure
Mild diarrhea dysentric syndrome
Dx with toxin assay
PO Flagyl (Vanc)
*At risk population for Salmonella (and therefore should be treated): infants <3mos and children with malignancies, hemoglobinopathies, and immunodeficiencies
HUS: renal failure, hemolytic anemia, thromboctopenia (don’t forget, can see with Shigella as well!)
Campylobacter GBS

23. Thanks for your attention!!
Noon Conference: JIA, Dr. Brown
Thanks for your attention!!