Pseudomonas aeruginosa

Question 1

Physical description of P. aeruginosa

Answer 1

• G negative rod with single polar flagellum

- very robust metabolic capacity can use wide variety of carbon sources

Question 2

Action of P. aeruginosa

Answer 2

-respiratory metabolism, but can use anaerobic respiration with NO3 as terminal electron acceptor

Question 3

Unique quality about P. aeruginosa

Answer 3

• fruity aroma

- blue green fluorescent pigments; pyocyanin, fluorescein, pyoverdin

Question 4

P. aeruginosa ability to quorum sense

Answer 4

• involved in biofilm formation, essential for spreading and colonization
• homoserine lactones and pseudomonas quinolone signal
• send out planktonic cells from biofilm

Question 5

Clinical presentation of P. aeruginosa

Answer 5

• opportunistic, nosocomial infection
• skin biofilms infections, BURN and DIABETIC patients
• CF pts have lung biofilms with persister cells
• otitis externa; swimmers, piercings
• eye infections; LASIK,surgery

Question 6

Further clinical presentation of P.aeruginosa

Answer 6

• UTI; catheters or bladder irrigations
• bacteremia and sepsis; leukemia, burn, diabetics
• ecthyma gangrenosum in diabetics(erythematous, non pyogenic ulcerations)

Question 7

Description of folliculitis with P. aeruginosa

Answer 7

• from contaminated water

- people with acne

Question 8

Epidemiology of P. aeruginosa

Answer 8

• nosocomial; in moist settings
• resident flora on moist skin areas; toe web, axilla but not invasive in immunocomp. people
• CF puts carry pseudo. as URT flora

Question 9

Pathogenesis of P. aeruginosa

Answer 9

• adhesion pili aid in initial stages of biofilm formation
• hypermutable strains in BFs
• persister strains selected by some antibiotics
• location in biofilms, and alginate capsule deter phagocytosis
• LPS endotoxin typical of G-
• type 3 secretion system parallel to that of Y. pestis

Question 10

Toxins of P. aeruginosa

Answer 10

• Exotoxins A and S
• A: ADP-riboyslates EF2
• B: ADP-riboyslates Hras p21; signals apoptosis
• elastase: destroy elastin in lungs
• pyocyanin/pyochelin: make toxin O2 radicals to kill host cells and native bacterial flora

Question 11

O2 radicals to kill host cells

Answer 11

• O2 to O2 radical by Pyocyanin

- O2 to OH radial by Pyochelin binding with Fe

Question 12

Control of P. aeruginosa

Answer 12

• sterile precaution around burn patients
• topical antimicrobials on wounds
• try to prevent BF formation
• very resistant to many antibiotics

Question 13

Medication for P.aeruginosa

Answer 13

• cipro. is often used
• cipro or aztreonam in combined therapy
• gentamycin + ticarcillin or carbenicillin for severe
• meropenem + levofloxacin may prevent resistance
• avoid mono therapy

Question 14

Description of acinetobacter baumanii

Answer 14

• nosocomial infection

- ventilator associated pneumonia, septicemia, high level of antibiotic resistance

Question 15

Description of Burkholderia cepacia

Answer 15

• similar opportunistic infection pattern to P. aeruginosa in CF pts
• catheter associated UTI
• causes onion rot in plants