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Pseudomonas aeruginosa

Etiology: risk factors 1) cystic fibrosis 2) diabetes mellitus 3) intravenous drug abuse (IVDA) 4) neutropenia 5) wounds 6) burns 7) urinary catheterization Epidemiology: 1) ubiquitous 2) nosocomial infections 3) community hot tubs/warm water pools Pathology: 1) breakdown of normal cutaneous or mucosal barriers 2) immunocompromised patients 3) normal flora eradicated by broad-spectrum antibiotics 4) endophthalmitis shows vascular necrosis without inflammatory cells [8] - P aeruginosa visible as blue haze surrounding vessel Clinical manifestations: 1) pneumonia a) severe b) necrotizing c) empyema may occur 2) endocarditis 3) sinusitis 4) swimmer's ear 5) malignant otitis externa in diabetics 6) eye infections - contact lens-associated keratitis - scleral abscess - endophthalmitis in adults - ophthalmia neonatorum in children [8] 7) septic arthritis 8) osteomyelitis 9) urinary tract infections 10) pyoderma 11) burn infection 12) hot-tub folliculitis 13) ecthyma gangrenosum in neutropenic patients with bacteremia Laboratory: - Pseudomonas aeruginosa serology - Pseudomonas aeruginosa DNA - Pseudomonas aeruginosa regA gene - Pseudomonas aeruginosa sodA gene - Pseudomonas aeruginosa multidrug-resistant in isolate - culture - light growth of Pseudomonas on sputum culture when the organism not seen on Gram stain is consistent with colonization rather that infection with Pseudomonas aeruginosa - glucose -; lactose -; pigment (pyacyanin fluorescein) - oxidase positive - growth-temp 42; motility via monotrichous flagella - MacConkey colorless - Gram negative bacillus; Gram negative rods - Blue-green pigment & fruity odor - Bipolar safety-pin shape Radiology: - chest X-ray may show bilateral patchy infiltrates Complications: - endophthalmitis may result in Pseudomonal sepsis Management: 1) antibiotic therapy a) empiric therapy for suspected Pseudomonas infection should include at least two antibiotics to which Pseudomona is susceptible - after culture & sensitivity determine antibiotic susceptibility, single antibiotic therapy is appropriate [9] b) antipseudomonal beta-lactam agent - 3rd generation cephalosporin - ceftazidime - cefoperazone - Cefepime - extended-spectrum penicillin - mezlocillin - piperacillin (18-24 g/day divided every 4-6 hours) - carbenicillin - ticarcillin - activity not enhanced by beta-lactamase inhibitor - Pseudomonas & other gram-negative bacilli may require a longer duration of therapy (10-14 days) [4,6] - 7 days of therapy for ventilator-pneumonia (Cefepime sensitive) [8] - carbapenem for ventilator-associated pneumonia due to extended-spectrum beta-lactamase producing gram-negative bacteria [5] b) fluoroquinolone or an aminoglycoside - among quinolones, ciprofloxacin has the best activity against c) combination therapy of beta-lactam plus fluoroquinolone or an aminoglycoside should be used for synergy & because resistance may develop to single agent therapy - Cefepime, imipenem, meropenem, or Zosyn plus an aminoglycoside plus a fluoroquinolone (dual Pseudomonas coverage) [5] d) other agents - imipenem - aztreonam - aminoglycoside plus fluoroquinolone - ceftolozane tazobactam & colistin for multidrug drug-resistant Pseudomonas [5,6] e) multidrug-resistant Pseudomonas aeruginosa - ceftolozane tazobactam [10] - consider adding once-daily tobramycin or amikacin for pyelonephritis [10] 2) complications a) empyema - drainage, - debridement of: - pus - necrotic material - removal of infected foreign material b) early valve replacement in left-sided endocarditis 3) cystic fibrosis - aggressive pulmonary toilet - ciprofloxacin 500-750 mg PO BID in adults for acute exacerbations of chronic lung infection 4) swimmer's ear - neomycin/polymixin B 3 drops TID for 7 days 5) hot tub folliculitis generally resolves spontaneously within 2 weeks [4]

Related

ecthyma gangrenosum

General

Pseudomonas

Properties

KINGDOM: monera DIVISION: SCHIZOMYCETES

References

  1. Manual of Medical Therapeutics, 28th edition, Ewald & McKenzie (eds) Little, Brown & Co, 1995, pg 301
  2. Harrison's Principles of Internal Medicine, 13th ed. Companion Handbook, Isselbacher et al (eds), McGraw-Hill Inc. NY, 1995, pg 227-228
  3. Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 797
  4. Journal Watch 21(17):140, 2001 Fiorillo L et al The pseudomonas hot-foot syndrome. N Engl J Med 345:335, 2001 PMID: 11484690
  5. Medical Knowledge Self Assessment Program (MKSAP) 15, 16, 17, 18. American College of Physicians, Philadelphia 2009, 2012, 2015, 2018
  6. Pogue JM, Marchaim D, Kaye D, Kaye KS. Revisiting "older" antimicrobials in the era of multidrug resistance. Pharmacotherapy. 2011 Sep;31(9):912-21 PMID: 21923592
  7. Cilloniz C, Gabarrus A, Ferrer M et al Community-Acquired Pneumonia Due to Multidrug- and Non-Multidrug- Resistant Pseudomonas aeruginosa. Chest. 2016 Aug;150(2):415-25. PMID: 27060725
  8. Elkston CA, Elkston DM Bacterial Skin Infections: More Than Skin Deep. Medscape. July 19, 2021 https://reference.medscape.com/slideshow/infect-skin-6003449
  9. NEJM Knowledge+
  10. Tamma PD, Heil EL, Justo JA, Mathers AJ, Satlin MJ, Bonomo RA. Infectious Diseases Society of America 2024 Guidance on the Treatment of Antimicrobial-Resistant Gram-Negative Infections. Clin Infect Dis. 2024 Aug 7:ciae403. PMID: 39108079 https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciae403/7728556