Pseudomonas and ICU GRNs Flashcards
What drugs can treat pseudomonas infections ?
1) Piperacillin + Tazobactam
2) 3rd Generation Cephalosporins: ceftriaxone, ceftazidime
3) 4th generation Cephalosporins: cefepime
4) Ciprofloxacin
5) Aminoglycosides: gentimycin, amikacin (used in combination, nephrotoxinc)
6) polymyxins (used with gentimycin, highly nephrotoxic)
7) aztreonam – but usually a bad choice; only if pen allergic
What are the common Manifestations of Pseudomonas?
- Pneumonia - HCAP, VAP, CAP
- Bacteremia, which can lead to endocarditis
- Ecthyma Grangrenosum (but not specific)
- Skin and soft tissue infections (burn patients)
- Wound infections
- Hot tub folliculitis
- Otits Externa (Swimmer’s ear; specific)
Rare: Osteomyelitis, UTI, eye infections
Microbiology/Biochemistry of Pseudomonas
- Gram Negative Rod
- Aerobic
- Non lactose Fermenting
- Oxidase Positive
- Grape like odor
Describe the microbiology and biochemistry of Pseudomonas?
○ Aerobic ○ Gram Negative Rod ○ Non-lactose fermenting ○ Glucose fermenting ○ Oxidase Positive
Epiemiology of Pseudomonas:
- where is it found
- who is at risk?
- where can it colonize ?
○ Ubiquitous in the environment
○ Throughout hospital environment
§ fluids (dialysis, ophthalmic, rinses, water taps)
§ equipment (whirlpools, respiratory, endoscopes, humidifiers, catheters)
- Airway is colonized by pseudomonas
Risk:
Disrupted physical barriers
Immune deficiencies
Chronic Lung disease (CF)
can colonize respiratory tract
Pathogenesis of Pseudomonas:
- Describe virulence factors
- How does it form biofilms
- what toxins does it secrete?
Virulence: Adherence: pili, flagella LPS - endotoxin -- biggest inducer of cytokine storm -- sepsis Polysaccharide capsule, slime ○
Biofilm formation: Type IV pili; deposit glycopeptide
Exotoxin A - ADP Ribosylating EF2 (similar to diphtheria toxin)
Type II Secretions (Exoenzymes – ExoS)
Degredative Enzymes:
PLC, Elastase, Cytotoxin, Proteases
What are the clinical Manifestations of Psuedomonas?
- PNA: (HCAP, VAP, CAP) – primarily nosocomial, possibly from hospital equipment
worse with aspiration - Bacteremia – which may lead to endocarditis
- Echthyma gangrenosum
- § Pseudomonas Skin and Soft tissue infections (burn patients, hot tub folliculitis, wound infections)
Otitis Externa
Osteomyelitis, Cath-UTIs, Eye infections
Describe the biochemistry of Acinetobacter baumanii
- ○ Gram Negative Coccobacillus ○ Non motile ○ Aerobic ○ Non-lactose fermenter ○ Glucose fermenter ○ Oxidase Negative (unlike pseudomonas)
Epidemiology of Acinetobacter:
- where does it colonize?
- risks for infection?
- Colonizes the skin, respirtaory and GI tracts
- Nosocomial pathogen of the ICU
- Opportunistic
-
Pathogenesis of Acinetobacter
- Survives for longer periods in dry conditions
- Polysaccharide capsule
Clinical Presentations of Acinetobacter
ICU patients
○ VAP ○ CAUTI -- cathater associated blood stream infection ○ CLABSI -- Central line associated blood stream infection ○ Wound infections ○ Sacral decubitous ulcers
Treatment for Acinetobacter
• Treatment of Acinetobacter — often use combination therapy
○ 3rd and 4th generation cephalosporins ○ Carbapenems ○ Beta Lactams w/ beta lactamase inhibitor § Ampicillin/sulbactam § Sulbactam has activity by itself ○ Fluoroquonones ○ Aminoglycosides ○ Polymyxins -- high toxicity ○ Tigecyclin -- gets into bone and abscesses well, but leaves the blood stream too quickly for bacteremia
name two other GN Rods of the ICU
what is the go to treatment
Stenotrophomonas maltophila
• Often colonizes respiratory tract (CF, Vents, etc)
Treated with TMP/SMX
- Burkholderia cepacia
- seen mostly in CF