Gram Negative Infections Flashcards
E. Coli
bacteria most often causes what type of illness?
GI
E. Coli
bacteria most often comes from what?
un/undercooked meats, raw flour, unpasteurized products, leafy greens, unwashed fruits
E. Coli
ETEC
Enterotoxigenic E. Coli
E. Coli
EIEC
Enteroinvasive E. Coli
E. Coli
Describe ETEC
heat stable toxin
common source of traveler’s diarrhea
E. Coli
Describe EIEC
invades cells leading to bloody diarrhea & dysentery
uncommon in the US
E. Coli
STEC
shiga toxin producing E. Coli
E. Coli
complications of STEC
hemorrhagic colitis
HUS
thrombotic thrombocytopenic purpura
E. Coli
Dx STEC
- Generic cultures not helpful, should specifically culture for O157:H7 and Shiga-toxin
E. Coli
Tx for STEC
DO NOT USE ABX, increases risk for HUS
if you must:
* Cipro, 500mg PO, Q12hrs
Salmonellosis
most common subspecies infection
enterica
Salmonellosis
Which subspecies causes enteric fever?
typi/paratyphi
Salmonellosis
which subspecies causes acute enterocolitis?
typhimurium
Salmonellosis
which subspecies causes septicemic type?
choleraesius
Salmonellosis typhi
MOA of infection
- organism breaches mucosal epithelium of intestines
- organism invade & replicate in macrophages in Peyer patches, mesenteric lymph, and spleen
- bacteremia results in infection localizing to lymp tissue of SI
- Peyer patches inflame leading to ulceration
- Organism dissemiates throughout body
Salmonellosis typhi
incubation period
6-30 days
Salmonellosis typhi
general clinical presentation
GI & constitutional sx
Salmonellosis typhi
Prodromal stage sx
7 things
- malaise
- headache
- cough
- sore throat
- abd pain
- constipation
- fever
Salmonellosis typhi
how long is prodromal stage?
first 7-10 days of being sx
Salmonellosis typhi
Later signs of typhi
5
- splenomegaly
- abd distension/tenderness
- bradycardia
- meningismus
- rash
Salmonellosis typhi
describe associated rash
onset, location, color, size, resolution
- 2nd wk
- on trunk
- pink papule
- 2-3mm
- resolves in 3-4 days
Salmonellosis typhi
what have people usually done before infection?
travelled
Salmonellosis typhi
dx
3 components
- leukopenia on CBC
- pos blood cultures
- pos stool cultures (not always reliable)
Salmonellosis typhi
when are people with typhi positive on blood cultures?
1st wk vs 3rd wk
- 80% pos in 1st week of sx
- only 25% pos by 3rd wk of sx
Salmonellosis typhi
complications
mortality, 2 most common
- 2% mortality when treated
- 30% mortality when untreated
- intestinal hemorrhage
- intestinal perforation
Salmonellosis typhi
Tx in sx pts
doage, frequency, duration
levofloxacin, 750mg PO, Q12/Q24
* 5-7 days for uncomplicated
* 10-14 days for severe infection
Salmonellosis typhi
tx for carriers
ciprofloxacin, 750mg PO, Q12, 4 wks
Salmonellosis typhi
Prevention
- vaccination (contact, travel, outbreaks)
- proper waste disposal
- minimize food/water contamination
- ill persons/carriers cannot work as food handlers
Salmonellosis- General Gastroenteritis
incubation period
8-48 hrs
Salmonellosis- General Gastroenteritis
sx
- fever, chills
- n/v/d (d may be bloody), 3-5 days duration
- abd pain/cramping
Salmonellosis- General Gastroenteritis
dx
- stool PCR or culture
may not require abx, typically self limiting
Salmonellosis- General Gastroenteritis
abx
Cipro, 500mg PO, Q12 hrs, 7-14 days
Yersinia
AKA
bubonic plague
Yersinia
zoonotically, how do people become ill with yersinia?
wild rodents are infected with yersinia and then bitten by fleas. when fleas contact humans, they can become infected.
Yersinia
P2P, how is Yersinia spread?
resp droplets
Yersinia
incubation period
7-10 days
Yersinia
infection pathophys
- enters via lymphatics to lymph nodes
- lymph nodes enlarge (buboes)
- can spread to bloodstream/organs
- fatal if meningitis or pneumonia develop
Yersinia
Where is this most commonly seen in the world? Where is it endemic in the US?
- 75% of cases in Madagascar
- CA, AZ, NV, NM
Yersinia
Sx
timing, 6 sx
sudden onset
1. high fever
2. malaise
3. tachycardia
4. intense headache
5. delirium- if meninges are involved
6. myalgias
Yersinia
signs
7 things
- tachypnea
- productive cough
- blood-tinged sputum
- cyanosis
- meningeal signs
- lymphadenopathy (LAD)
- purpuric spots
Yersinia
Dx
- lymph node aspiration w/ culture
- Ab titer
Yersinia
Tx
- immediate upon suspicion
- Streptomycin 1g IV, Q12 hrs, 10 days
- Respiratory isolation if pneumonia
Yersinia
Prophylaxis for Contacts
Abx prescribed
Doxy, 100mg PO, Q12 hrs, 7 days
Yersinia
Prevention
avoid exposure to rodents/flears in endemic areas
Haemophilus
colonize where in who?
upper resp tract in pts with COPD
Haemophilus
Risk factors
5 things
- alcoholism
- tobacco use
- advanced age
- chronic lung disease
- HIV infection
Haemophilus
can cause what type of infections ?
9 types
- sinusitis
- otitis
- bronchitis
- epiglottitis
- pneumonia
- cellulitis
- arthritis
- meningitis
- endocarditis
Haemophilus
Tx for non beta-lactamase producing strains
amoxicillin
Haemophilus
tx for beta-lactamase producing strains
who is this more common in?
amoxicillin-clavulonate (augmentin)
children