• gram neg non sporulating bacilus
• obligate aerobe except with nitrate
• does not ferment carbs
• oxidase positive
• appears blue green due to pyocyanin
• produce mucoid exopolysac. (problem in CF patients)

• ubiquitis in soil, plants, moist envir., animals, man
• potential reservoirs
  • flowers
  • uncooked veggies
  • hospital sinks
  • medical equipment
• nosocomial
• associated with immunosuppression and high mortality

• immunosup.
• hematologic malignancies
• ICU
• trauma
• drug indection
• surgery
• CF
• prolonged hyospitalization
• thermal injury
• mucosa injury

An infection of debilitated

• usually found in nasal mucosa, skin, oral, stool
• can adopt to any damp envir. (unlike other gram neg organism)
• because it lacks specific environmental selectivity, it is easily spread among ICU patients predisposed to infection
• colonization predisposes patients to invasive infection

• colonize damaged tissue
• damage the mucosal tissue (cytotoxic chemotherapy or endotracheal usage)
• elaborate toxins
• disseminate

• pilli (mediate attachment
• alginate (mediate attachment, block phagocytosis)
• outer cell membrane (block phagocytes, barrier to Ab, complement)
• flagella (motility)
• endotoxin (antiphagocytic, stimulate cytokine production)

• elastase- dissolution of lamina propria
• alkaline protease- corneal, alveolar necrosis
• exotoxin A- inh. protein syn., cellular necrosis
• exoenzyme S- inhibit protein syn., promote dissemination
• pyroverdin- scavenges iron
• pyocyanin- produce reactive oxygen species

• most toxic VF
• inhibit protein syn. rapidly
• produced in more than 80% of isolates
• causes tissue necrosis
• mechanism of action
  • target EF2 and ADP ribosylates it

• ottitis externa
• whirlpool folliculitis
• ulcerative keratitis
  • extended wear contact lens
  • sneaker osteomyelitis
• toe web infections
• endocarditis
• CF

• UTI
• pneumonia
• bacteremia
• typhilitis
• meningitis
• soft tissue
• burns

• paronychia (green nail syndrome)
• toe web infection
• pyoderma
• cellulitis
• ecthyma gangrenosum
• subQ nodules
• burn wound sepsis

• otitis externa (swimmer's ear)
  • swimmers in humid climates
  • self limited, rarely invades canal
• malignant otitis externa
  • found in diabetics
  • bone cartilage junction in the floor of the ear canal
  • significant mortality
• chronic

• symptoms
  • pain
  • edema
  • tenderness of soft tissue
  • purulent discharge
• pathology
  • granulation tissue on floor of auditory canal
  • may involve:
    • parotids
    • TMJ
    • facial nerve
    • mastoids
    • skull

• serogroup O:11 of P aeruginosa
• seen in those who are in hot tubes and swimming pools located in the area covered by bathing suit and apocrine sweat glands
• incubation- 8 hours-5 days (usually 48 hrs)
• gross appearance
  • diffuse
  • pruritic
  • maculopapular
  • vesicular

Bone and joint infections of Pseudomonas aeruginosa

• hematogenous
  • IVDA or pelvic source
  • cartilaginous joints- SC, pubis symphysis, sacroiliac, vertebral
• direct inoculation (sneaker injury)

• typhilitis- necrotizing cecal infection in neutropenic patients
• perectal abscess- neutropenic patients
• diarrheal disease (in kids)
• shanghai fever (mimic enteric fever)

• ICU patients
• neutropenic cancer patients
  • usually see the "big four"
    • E coli
    • Klebsiela
    • Pseudomonas
    • S. aureus
• burn wound patients
• AIDS patients receiving trimethorim/sulfamethoxasole prophylaxis

• debilitated host
  • it's the host, not the bug
• microbial VF's
• antimicrobial resistance
  • multidrug resistant organism

• inherent- basic property of an organism
  • ex: bacteria do not bind aminoglycosides
• acquired- function of environment
  • increased synthesis of beta lactamase in response to exposre to beta lactam antibiotic