Bugs Week 4 Flashcards

Question

Campylobacter jejuni

Answer 1

Sketchy - Camping Guy and Bears Gram - Bacilli Microaerophilic Motile Cold sensitive MCC of bacterial food borne illness Zoonosis from animals/animal products (chicken). Karmali agar is selective medium (charcoal-based w/ vanco, cefoperzone, and cyclohexamide). Sensitive organism. Sx:Diarrhea and cramping, abdominal pain, and fever. Can last a week. Can be bloody diarrhea. Can have vomiting. Mechanism = inflammatory response to cell invasion. Incubation period: 2-5 days. Positive dx: stool culture Possible complication = Guillain-Barre; Reactive arthritis

Answer 2

Sketchy - Santa's list ``` Gram + Bacilli Non-fastidious* Flagellated, motile Non spore forming Oxidase - ``` B-hemolytic (under colonies) Rare illness, a leading cause of death by food born illness. Listeriosis = mild GI infection for most. Most vulnerable are older adults, pregnant women, newborns, and opportunistic. Meningitis and sepsis in vulnerable populations. Dx: Bacterium in normally sterile site (not stool!) Mechanism for invasion: immune cells spread listeria to other organs; trojan horse; liver is a major target. Common sources: Sprouts, deli meats and hot dogs, smoked seafood, soft cheeses, raw milk

Answer 3

Sketchy - Colonel Cholera sets up Base cAMP ``` Gram negative Vibrio (curved rod) Facultative anaerobes Flagellated, motile Oxidase + ``` Water loving Kovacs oxidase reagent turns purple. Sx: Fairly mild bloody diarrhea, stomach cramps, fever, nausea and/or vomiting. Sx last less than a week. Immunocompromised it can spread to the blood --> deadly infections. Mechanism = enterotoxins: hemolysins TDH and or TRH. Form pores in RBCs but also in epithelial cells Dx: vibrio isolated Resevoirs = shell fish.

Answer 4

Sketchy: She Gorilla's Circus ``` Gram negative bacillus Facultative anaerobe Nonmotile Non spore forming Mainly lactose negative H2S negative ``` Very closel related E. coli. Invasive Shigella sonnei: most shigella caused GI illness Shigella flexnori: causes bacillary dysentery (and reactive arthritis) Shigella dysenteriae: Rarest but most severe dysentery. Transmission: fecal-oral Many access through M cells thorugh type III secretion system. Actin rockets to move around Antibiotics in severe cases. Can cause HUS.

Answer 5

Most shigella caused GI illness Sx: Diarrhea (often bloody), fever, stomach cramps, sx start 1-2 days following exposure. Usually resolve in 5-7 days.

Answer 6

Frequent, small bowel movements w/ blood and mucus. Accompanied by rectal pain and spasms (tenesmus) MC bacillary form is Shigella flexnori Most severe bacillary dysentery = Shigella dysenteriae Amebic dysentery = Entomoeba histolytica Invasive plus has a phage-born toxin Shiga toxin, also casued verotoxin (A-B) toxin that acts on vascular endothelial cells.

Answer 7

Sketchy - E cola's fountain soda (traveling water truck) ``` Gram negative bacillus Facultative anaerobe Motile Non spore forming Mainly lactose positive ``` Traveler's diarrhea, diarrhea in children SX: profuse watery diarrhea and abdominal cramping. Fever, chills. N/V, anorexia. Typically lasts 3-4 days, less than 10 Incubation period: 1-3 days Rx: not abx Track outbreaks w/ commercial PCR and antibody based kits. Typical reservoir = under-cooked beef or unclean veggies

Answer 8

Sketchy - E cola's fountain soda (kid on red stool) ``` Gram negative bacillus Facultative anaerobe Motile Non spore forming Mainly lactose positive ``` Shiga toxin w/ outbreaks in US O157:H7. Toxin is an AB5 toxin. SX: profuse watery diarrhea and abdominal cramping. Can progress to bloody diarrhea. Fever, chills. N/V, anorexia. Typically lasts 3-4 days, less than 10 Hemorrhagic colitis and/or HUS. Children more vulnerable. Incubation period: 1-3 days Rx: not abx Track outbreaks w/ commercial PCR and antibody based kits. Typical reservoir = under cooked beef or unclean veggies

Answer 9

Sketchy - Colonel Cholera's Base cAMP. ``` Gram negative Vibrio (curved rod) Facultative anaerobes Flagellated, motile Oxidase + ``` Kovacs oxidase reagent turns purple. Water is primary resevoir. Fecal oral transmission. Typically only serogroups O1 and O139 produce cholera toxin --> acitvates AC --> increase cAMP --> chloride in lumen --> water follows. Acute illness: Rice water stools w/ severe dehydration. Dx: by isolating causative organism from stools. Rx: ORS/IV fluids.

Answer 10

Sketchy - Salmon dinner Gram - Bacillus NON spore forming H2S positive and lactose negative Motile, flagellated Infections are 50x less common than nontyphoidable salmonellosis in US Typhoid fever not typhus (rickettsial infection) Fecal oral transmission Vaccine available. Life threatening illness in GI tract --> bloodstream. Sx: high fevers (103-104), weakness and headache. Stomach pains, anorexia, diarrhea OR constipation. Sometimes a rash of flat, rose colored spots Antibiotic treatment is recommended!

Answer 11

Shigella, Giardia, Entamoeba, Norovirus, cryptosporidosis and STEC (EHEC) E coli. Medium is not grossly infected Secondary cases common. Can be spread in day-care centers, families. Example: toddler contacts cryptosporidosis in wading poool

Answer 12

Vibrio cholera, C. perfingens. Medium is highly contaminated Secondary cases are rare I.e. traveler gets cholera from seafood carried to US from Ecuador on luggage

Answer 13

Sketchy - Field trip to the Chocolate Factory Gram + (variable) bacilli Spore forming Obligate anaerobe Motile Exotoxins cause cell death, shallow ulcers, pseudomembranes. Early lesions are superficial. May enventually invade. Pseudomembranous colitis. Can cause diarrhea (MC), pseudomembranous colitis, fulminant colitis (danger for perforation). Infection induces enterocyte apoptosis. Dx: w/ toxin detection Rx: Metronidazole, oral vancomycin (and fidaxamicin); bowel resection or fecal transplant. Severe disease

Answer 14

``` RNA virus Icosahedral nucleocapsid Nonenveloped DS segmented Genome (III) Reovirdae (Repetovirus) ``` Spread fecal-oral Cytolytic and toxin-like action on intestinal epithelium causes loss of electrolytes Most serious in individuals under 2 (not before 6 months --> IgA in breast milk). Asymptomatic over 5 years old. Large amounts of virus are released during diarrheal phase. Maximal at 2-5 days after the beginning of diarrhea. Outbreaks MC at day care centers, preschools, and among hospitalized infants. --> higher cases in winter. ELISA, RTPCR, or electron microscopy Double capsid structure (removed by stomach --> ISVP is infectious Group A most common (determined by VP6) NSP4 stimulates release and cell lysis 2 vaccines: Rotarix (single strain) and Rotateq (5 strains)

Answer 15

MCC of foodborne disease outbreaks in the US. SS + RNA virus (Class IV) Icosahedral Nucleocapsid Nonenveloped Calcivirae Fecal-oral transmission Outbreaks of gastroenteritis. Disease resolves after 48 hrs. w/o serious consequences Can mutate quickly (drift)

Answer 16

DS DNA Virus Linear (class I) Icosahedral nucleocapsid Nonenveloped Adenoviridae ELISA or PCR Careful handwashing, chlorination of swimming pools, supportive care. Live oral vaccine for types 4 and 7 given to Military