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Morning Report: Thursday, January 12 th. Welcome APPLICANTS!. Shigella Infection. Epidemiology. Common cause of bacterial diarrhea worldwide (especially in developing countries) In the US: Third in frequency (after Salmonella and Campylobacter) Primarily affects children - PowerPoint PPT Presentation
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WELCOME APPLICANTS!
Morning Report: Thursday, January 12th
Shigella Infection
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
The Details… Gram-negative bacilli Four species:
S. dysenteriaeS. boydiiS. flexneriS. sonnei
Most common subtypes in the US
Only Shiga toxin-producing species!
Transmission *Person-to-person via the fecal-oral
routeTransmission in institutions
○ *Child care centersGrouping of susceptible childrenLack of adherence to hand-washing proceduresSmall inoculum required for disease production
Food borne transmission○ Cold salads○ Raw veggies
Sexual transmission
Clinical Presentation Incubation period 1-7 days, average 3
days Range of GI illness
Mild diarrhea life-threatening dysentary
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 HASeizuresMeningeal signsLethargyDelirium/ hallucinations
Physical Exam VS: high fever (>102F) Gen: toxic-appearing Abd: lower quadrant abdominal pain,
distension GU: tenderness on rectal exam
+/- signs of dehydration
Laboratory Findings Bandemia Stool microscopy
Large number of PMNs+/- RBCs
Stool cultureSend stool specimen promptly to labCan be grown on MacConkey or Hektoen-
Enteric agarsAlways want speciation and sensitivities
*Treatment Mainstay= SUPPORTIVE CARE!
Correction of fluid and electrolyte losses○ Substantial volume depletion uncommon○ Hyponatremia
NO intestinal antimotility drugsEarly restoration of oral intake
*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?
*Treatment Who to treat?
Red Book○ Severe disease○ Underlying immunosuppressive conditions○ Dysentery○ In mild cases Rx to prevent spread of the
organism
*Treatment What to use?
Parenteral ○ Ceftriaxone○ Cipro
Oral○ Azithromycin
First-line oral Rx for children <18yo when Abx susceptibility is unknown
○ FluoroquinolonesFirst-line oral Rx for children >17yo and adults
*Treatment What to use?
Oral○ Cefixime
Alternative to azithromycin in children <18yo○ Ampicillin or TMP-SMX
Only if sensitivities are known
Control Measures Most importantly….
METICULOUS HAND HYGIENE!!!
Control Measures Hospital
Contact precautions *Day care
Notify local health departmentStool cultures should be performed on all
symptomatic attendees and staffAffected persons should be excluded until:
○ Initiation of appropriate ABx○ ≥24 hours after diarrhea has resolved○ Stool cultures are negative for Shigella
Complications Intestinal
Proctitis or rectal prolapseToxic megacolonIntestinal obstructionColonic perforation
Complications Systemic
BacteremiaMetabolic disturbancesLeukemoid reactionNeurologic diseaseReactive arthritis
○ Alone or in association with conjunctivitis and urethritis (Reiter syndrome)
Hemolytic-uremic syndrome○ Caused by EHEC (O157:H7), S. dysenteriae
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
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
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
Infectious DiarrheaTransmission 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
Campylobacterjejuni
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
Fever, diarrhea with blood/ mucous
+stool WBC, RBC; look for signs of HUS
Abx not indicated! (increases risk for HUS)
Yersiniaenterocolitica
Pork (chitterlings) Dysenteric syndrome, can mimic appy/ Crohns
+stool WBC, RBC Bactrim, aminoglycosides, cephalosporins (3rd), quinolones
Clostridiumdifficile
ABx exposure Mild diarrhea dysentric syndrome
Dx with toxin assay
PO Flagyl (Vanc)
Thanks for your attention!!
Noon Conference: JIA, Dr. Brown