Micro images Flashcards
What would you expect to see on gram stain of the organism cultured from the finding here?
Gram - coccobacilli
(Intra-abdominal abscess = bacteroides fragilis)
List 4 virulence factors of this organism.
- VacA
- CagA
- Urease
- PAI-assc. Type III secretion system
Organism in 2nd and 3rd tube?
2nd = Salmonella (produces H2S = black butt)
3rd = Shigella (ferments glucose only = yellow butt + red slant)
What two species could be represented on this MacConkey agar?
Shigella or Salmonella (lac -)
How do you get this infection?
Prior antibiotic use
(Note the pseudomembrane over the colonic mucosa)
In which patients would this complication occur?
Immunocompromised and chronic liver disease patients
(Bullae = V. vulnificus)
Histology of tissue infected with this microbe would reveal ____. What symptoms would the patient exhibit?
Cytoplasmic inclusion bodies (viroplasms where assembly occurs)
Young child/infant with diarrhea
(Two outer shells + double-stranded RNA = rotavirus)
How would the infection represented below present?
Persistent diarrhea in a young kid with no inflammation or fever
(Aggregation of bacteria = EAEC)
How would the patient from whom this sample was collected present?
Fever, appendicitis-like abdominal pain, watery diarrhea followed by dysentery
(Gull-winged appearance = C. jejuni)
This finding on a fecal smear is indicative of:
Shigella
(Lots of leukocytes due to propulsion from M cells into epithelial cells = shallow ulcers)
This schematic represents which infection?
Typhoid fever
Who is most likely to become ill due to this organism?
Immunocompromised patients
(Currant jelly = Klebsiella; opportunistic pathogen)
What virulence factor causes this finding?
Shiga-like toxin (Stx) of EHEC
(Causes inhibition of protein synthesis, thus cell death, of enterocytes)
The pathogenesis of which microbe is shown below?
ETEC
(LT - activates AC; ST - activates CFTR)
A patient presents with high fever and confusion. His vitals are 102, 100/60, 50, 22. You notice the below finding on physical exam as well as splenomegaly. CBC reveals WBC 2.0 with PMNs 20%. Dx?
Typhoid fever
(Rose spots; neutropenia + splenomegaly + bradycardia = S. typhi)
Which enteric organisms can cause the findings below?
Shigella, Salmonella, Yersinia, Campylobacter
(Reiter’s syndrome = polyarthritis in large joints, urethritis, conjunctivitis))
This type of infection is particularly common in which susceptible group?
Sickle cell anemia kids
(Salmonella osteomyelitis)
Which results are consistent with inflammatory diarrhea?
Lactoferrin and calprotectin + samples
(Both indicators of WBCs in stool)
What other manifestation common to the causative agent of this finding may be present?
Conjunctivits
(Enanthema = vesicles on oral mucosa = coxsackie A; coxsackie and echoviruses can cause conjunctivitis)
This is the most common cause of:
Hemorrhagic colitis
(Stx = shiga-like toxin = EHEC)
Ddx?
Bacteroides fragilis (intra-abd abscess, PID, or pulmonary infection)
Prevotella melaninogencia (pulmonary or periodontal abscess)
A patient presents with sudden onset of joint pain in both knees. His eyes are red and swollen, about which he says he must have picked up “pink eye” from his son. He also admits a couple week history of watery diarrhea, fever, and abdominal pain radiating to the back. CT reveals the below finding, indicated by the arrow. Diagnosis?
Yersinia enterocolitica with Reiter’s syndrome
(Mesenteric lymphadenitis shown in CT + appendicitis-like pain = Yersinia; arthritis + conjunctivitis + urethritis = Reiter’s syndrome, a complication of Salmonella, Shigella, Yersinia, and Campylobacter)
This organism was cultured from a hospitalized patient with a UTI. Dx?
Serratia
(Brick-red colonies)
What is denoted by the star?
Attachment-Effacement lesion of EHEC/EPEC
(LEE gene product causes rearrangement of actin to create pedestal that aids in EHEC/EPEC attachment)
The results from the diagnostic method shown below would indicate treatment with:
Omeprazole, metronidazole, clarithromycin
(Urea breath test = H. pylori)
A person traveling to these areas may consider vaccination against:
Salmonella typhi
Dx?
Vibrio
(Gram - curved rods)
What is unique about the bug represented below?
Unlike other E. coli, it’s non-motile, doesn’t ferment lactose, and doesn’t decarboxylate lysine
(Replicating in intestinal cells = EIEC)
A patient presents with a 5 day history of diarrhea that has had some blood. She also reports LLQ cramping. You suspect a bacterial etiology and prescribe an antibiotic. She returns 10 days later with persistent diarrhea. How should you treat now?
Metronidazole for a parasite, like Giardia shown below
(Diarrhea for >2 weeks suggests parasite)
The organism whose pathogenesis is depicted here produces what appearance on a KIA slant?
Red slant + yellow butt, no gas
(Shigella = enter M cells, escapes phagocytic vesicle, extends into neighboring enterocytes)
Which would be E. coli? What could be in tube B?
Tube E is E. coli (yellow butt + yellow slant b/c it’s lac+)
Pseudomonas (doesn’t ferment carbs = red butt + red slant)
What would you expect to see on culture of this finding?
Dark-colored colonies
(Periodontal abscess = Prevotella melaninogencia)
The microbe whose replication scheme is outlined below causes what kind of diarrhea?
Watery diarrhea
(Processing in endo-lysosome –> assembly in cytoplasmic viroplasm/inclusion body –> release by cell lysis = rotavirus)
Describe the pathogenesis of these lesion
C. diff toxin A is an enterotoxin and toxin B is cytotoxic and causes inflammation
What this is?
Salmonella inside of a macrophage
(Enters small intestine through M cells, then produces local infection in macrophages in lamina propria)
What genus is represented on this MacConkey agar?
Enterobacteriaceae
(Ferment lactose - pH indicator turns pink)
A mother brings in her son complaining of the “rash” seen below and that he seems to be sleeping a lot more in the past few days. She mentions that he has had diarrhea for about 9 days but in the last 2 days has stopped urinating when he passes stool. She read online that diarrhea should self-resolve so has just been keeping him hydrated at home. You note that his sclera appear icteric. What labs/tests should you order?
Creatinine
Blood smear
Platelet count
Sorbitol MacConkey agar
(Petechia in image suggests thrombocytopenia; icterus + fatigue suggests hemolytic anemia; history of diarrhea + oliguria + other findings suggests HUS due to EHEC)
This awesome drawing represents which pathogen?
S. typhi
(All Salmonella have H + O antigens; S. typhi has Vi ag = capsular antigen; rest are not encapsulated)
Which infectious disease would most likely be caused by the organism with this characteristic growth pattern?
UTI
(Proteus = swarming)
An otherwise healthy 7-year-old boy presents with stiff neck and fever. No bacteria are seen on gram stain of the CSF, and no capsule particles are seen on agglutination. CSF glucose is slightly low, and the white count is below 500 with mostly lymphocytes. Most likely causative agent?
Enterovirus
(Lymphocytes + nothing on gam stain suggests viral origin; enteroviruses are the most common cause of aseptic meningitis in kids; also E coli and Citrobacter would show up as gram - rod on gram stain)
