Pseudomonas Infection Workup
- Author: Selina SP Chen, MD, MPH; Chief Editor: Russell W Steele, MD more...
Laboratory Studies
Pseudomonas aeruginosa and other Pseudomonas organisms are aerobic, nonfermentative, nonenterobacterial gram-negative bacilli. Obtain 2 sets of blood cultures (ie, aerobic and anaerobic bottles) from different sites before starting empiric antibiotics. The following laboratory results are helpful to confirm a pseudomonal infection:
- CBC counts revealing leukocytosis with a left shift and bandemia, which indicates possible presence of toxic granulations or vacuoles
- Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels, which may be elevated in infection
- Metabolic profile revealing any electrolyte abnormalities, degree of dehydration, and worsening renal function
The following additional studies may be indicated, depending on the site of infection:
- Culture of the purulent discharge helps diagnose suppurative otitis media or malignant otitis externa.
- Corneal scrapings and culture may reveal pseudomonal involvement.
- Culture of vegetations from patients with pseudomonal infectious endocarditis (IE) reveals high quantities of the organisms, although diagnosis is usually confirmed by a repeated blood culture.
- Sputum Gram stain and culture may be indicated to evaluate for respiratory infection. This is especially recommended in children who may be predisposed to such infections.
- Blood gas levels may reveal hypoxemia, with or without hypercarbia.
- Wound and burn cultures can be helpful to identify pseudomonal infections.
- Urinalysis with culture and sensitivity is helpful when evaluating for urinary tract infection (UTI). Although rare, sloughing of vesical membrane in the urine can indicate complications of pseudomonal infections.
- Obtain stool cultures in patients with diarrhea. Note, however, that pseudomonal organisms produce no toxins.
Diagnosis of glanders can be confirmed by isolating B mallei from blood, sputum, urine, or skin lesions. No serologic tests are available. Diagnosis of melioidosis can be confirmed by isolating B pseudomallei from the blood, urine, sputum, or skin lesions. Detecting antibodies to the bacteria in the blood is another method.
Imaging Studies
- Chest radiography
- Patients with cystic fibrosis (CF) may have a small heart, depressed diaphragm, and increased anteroposterior chest diameter. Chest radiography may also reveal cyst formation, mucus plugging of dilated bronchi, generalized bronchiectasis, patchy atelectasis, peribronchial thickening, overaeration, or extensive peribronchial infiltration.
- The classic presentation of bacteremic pseudomonal pneumonia includes rapid progression of radiographic findings. Chest radiography performed within 48-72 hours after initial fever onset reveals parenchymal involvement with interstitial and alveolar infiltrates. Cavitation appears after 48 hours.
- Typical findings include (1) poorly-defined, hemorrhagic, often subpleural, nodular areas with a small central area of necrosis and (2) multiple, 2-mm to 15-mm, necrotic, umbilicated nodules with hemorrhagic parenchyma, representing the pulmonary component of an ecthyma gangrenosum (EG) skin lesion.
- The typical progression of disease is from pulmonary vascular congestion to pulmonary edema to necrotizing bronchopneumonia.
- Radiographs of patients with primary nonbacteremic pneumonia are similar to those from patients whose pneumonia is caused by Staphylococcus aureus. Among the common features are a diffuse bronchopneumonia (usually bilateral with distinctive nodular infiltrates with small areas of radiolucency) and pleural effusions; empyema or lobar consolidation is occasionally observed.
- CT scanning
- A CT scan of the head may reveal a brain abscess. A CT scan of the surrounding soft tissue and osseous lesions is recommended in patients with malignant otitis externa to help define the intracranial and extracranial extent of disease.
- Perform a CT scan of the abdomen as part of the workup for endocarditis, especially left-sided disease. Complications such as splenic abscesses require splenectomy before valvular replacement.
- A CT scan of the chest is not usually indicated, except when respiratory failure requires better definition of chest involvement. With left-sided endocarditis, a CT scan of the chest also can reveal septic pulmonary emboli as a complication.
- A CT scan of soft tissue and bone of skin infections may be required to exclude an abscess formation or osteomyelitis.
- MRI
- Consider MRI of the head to evaluate a patient with a brain abscess. MRI of the head in a patient with left-sided endocarditis may show cerebritis and mycotic aneurysm.
- A CT scan or MRI of the surrounding tissue of the site of infection may be needed to delineate abscess formation.
- Other studies
- Echocardiography (ECHO) may reveal vegetations in endocarditis. However, because the yield is low, consider a transesophageal ECHO or repeat ECHO for highly suspicious cases.
- Bone radiography or a nuclear study is helpful in diagnosing patients with suspected osteomyelitis.
- Renal ultrasound may be helpful to evaluate patients with a suspected obstruction or abscess formation complicating a UTI.
- A gallium WBC scan may help determine the extent of infection.
Other Tests
- To evaluate eye infections to determine the degree of corneal involvement, perform fluorescein staining and slit-lamp examination of the cornea.
- Patients who develop septic pulmonary emboli as a complication may require a ventilation-perfusion scan.
- A Wood light examination of a pseudomonal toe web reveals a green-white fluorescence from the elaboration of pyoverdin.
Procedures
- Needle biopsy or aspiration of the joint, possibly with fluoroscopic guidance, can be helpful in identifying the infectious organism. An open biopsy may be necessary, depending on disease extent.
- Lumbar puncture is indicated when CNS involvement is suspected. Workup of neonatal sepsis should include lumbar puncture, if indicated.
- Cardiac catheterization may reveal valvular involvement or vegetations.
- Quantitative cultures from bronchoalveolar lavage obtained by bronchoscopy helps distinguish infection from colonization.
- Thoracentesis may be indicated for patients who have pleural effusion.
Histologic Findings
- Histological findings of EG include edema, epidermal necrosis, and gram-negative rods on tissue gram stain.
- Few neutrophils in the sparse inflammatory infiltrate can also be seen.
Bendiak GN, Ratjen F. The approach to Pseudomonas aeruginosa in cystic fibrosis. Semin Respir Crit Care Med. Oct 2009;30(5):587-95. [Medline].
Pollack M. The Virulence of Pseudomonas aeruginosa. Rev Infect Dis. 1984;6:S617-26.
Burkholder W. Sour skin, a bacterial rot of onion bulbs. Phytopathology. 1950;40:115-8.
Rosenfeld M, Emerson J, McNamara S, et al. Risk factors for age at initial Pseudomonas acquisition in the cystic fibrosis epic observational cohort. J Cyst Fibros. May 1 2012;[Medline].
Morgan DJ, Rogawski E, Thom KA, et al. Transfer of multidrug-resistant bacteria to healthcare workers' gloves and gowns after patient contact increases with environmental contamination. Crit Care Med. Apr 2012;40(4):1045-51. [Medline].
Kielhofner M, Atmar RL, Hamill RJ, Musher DM. Life-threatening Pseudomonas aeruginosa infections in patients with human immunodeficiency virus infection. Clin Infect Dis. Feb 1992;14(2):403-11. [Medline].
Giamarellou H, Antoniadou A. Antipseudomonal antibiotics. Med Clin North Am. Jan 2001;85(1):19-42, v. [Medline].
[Guideline] Committee on Infectious Diseases. The use of systemic fluoroquinolones. Pediatrics. Sep 2006;118(3):1287-92. [Medline].
Douidar SM, Snodgrass WR. Potential role of fluoroquinolones in pediatric infections. Rev Infect Dis. Nov-Dec 1989;11(6):878-89. [Medline].
Carmeli Y, Troillet N, Eliopoulos GM, Samore MH. Emergence of antibiotic-resistant Pseudomonas aeruginosa: comparison of risks associated with different antipseudomonal agents. Antimicrob Agents Chemother. Jun 1999;43(6):1379-82. [Medline].
Altemeier WA, Tonelli MR, Aitken ML. Pseudomonal pericarditis complicating cystic fibrosis. Pediatr Pulmonol. Jan 1999;27(1):62-4. [Medline].
Arbulu A, Holmes RJ, Asfaw I. Tricuspid valvulectomy without replacement. Twenty years' experience. J Thorac Cardiovasc Surg. Dec 1991;102(6):917-22. [Medline].
Ashdown LR, Guard RW. The prevalence of human melioidosis in Northern Queensland. Am J Trop Med Hyg. May 1984;33(3):474-8. [Medline].
Baltch AL, Griffin PE. Pseudomonas aeruginosa bacteremia: a clinical study of 75 patients. Am J Med Sci. Sep-Oct 1977;274(2):119-29. [Medline].
Baum J, Barza M. Topical vs subconjunctival treatment of bacterial corneal ulcers. Ophthalmology. Feb 1983;90(2):162-8. [Medline].
Brewer SC. Clinical Investigations in Critical Care: Ventilator-Associated Pneumonia due to Pseudomonas aeruginosa. Chest. 1996;109:4:1020-30.
Byrne S, Maddison J, Connor P, et al. Clinical evaluation of meropenem versus ceftazidime for the treatment of Pseudomonas spp. infections in cystic fibrosis patients. J Antimicrob Chemother. Jul 1995;36 Suppl A:135-43. [Medline].
Cleveland RP, Hazlett LD, Leon MA, Berk RS. Role of complement in murine corneal infection caused by Pseudomonas aeruginosa. Invest Ophthalmol Vis Sci. Feb 1983;24(2):237-42. [Medline].
Cunha BA. Antibiotic resistance. Med Clin North Am. Nov 2000;84(6):1407-29. [Medline].
Davis SD, Sarff LD, Hyndiuk RA. Comparison of therapeutic routes in experimental Pseudomonas keratitis. Am J Ophthalmol. May 1979;87(5):710-6. [Medline].
Edgeworth JD, Treacher DF, Eykyn SJ. A 25-year study of nosocomial bacteremia in an adult intensive care unit. Crit Care Med. Aug 1999;27(8):1421-8. [Medline].
EORTC International Antimicrobial Therapy Cooperative Group. Ceftazidime combined with a short or long course of amikacin for empirical therapy of gram-negative bacteremia in cancer patients with granulocytopenia. N Engl J Med. Dec 31 1987;317(27):1692-8. [Medline].
Fagon JY, Chastre J, Domart Y, et al. Nosocomial pneumonia in patients receiving continuous mechanical ventilation. Prospective analysis of 52 episodes with use of a protected specimen brush and quantitative culture techniques. Am Rev Respir Dis. Apr 1989;139(4):877-84. [Medline].
Germiller JA, El-Kashlan HK, Shah UK. Chronic Pseudomonas infections of cochlear implants. Otol Neurotol. Mar 2005;26(2):196-201. [Medline].
Giamarellou H. Empiric therapy for infections in the febrile, neutropenic, compromised host. Med Clin North Am. May 1995;79(3):559-80. [Medline].
Giamarellou H. Malignant otitis externa: the therapeutic evolution of a lethal infection. J Antimicrob Chemother. Dec 1992;30(6):745-51. [Medline].
Gitterman B. In Brief: Aminoglycosides. Pediatrics in Review. Aug 1998;19(8):285.
Griffiths AL, Jamsen K, Carlin JB, et al. Effects of segregation on an epidemic Pseudomonas aeruginosa strain in a cystic fibrosis clinic. Am J Respir Crit Care Med. May 1 2005;171(9):1020-5. [Medline].
Harris A, Torres-Viera C, Venkataraman L, et al. Epidemiology and clinical outcomes of patients with multiresistant Pseudomonas aeruginosa. Clin Infect Dis. May 1999;28(5):1128-33. [Medline].
Highsmith AK, Le PN, Khabbaz RF, Munn VP. Characteristics of Pseudomonas aeruginosa isolated from whirlpools and bathers. Infect Control. Oct 1985;6(10):407-12. [Medline].
Ho PL, Chan KN, Ip MS, et al. The effect of Pseudomonas aeruginosa infection on clinical parameters in steady-state bronchiectasis. Chest. Dec 1998;114(6):1594-8. [Medline].
Husson MO, Richet H, Aubert A, et al. In vitro comparative activity of meropenem with 15 other antimicrobial agents against 1798 Pseudomonas aeruginosa isolates in a French multicenter study. Clin Microbiol Infect. Aug 1999;5(8):499-503. [Medline].
Isles A, Maclusky I, Corey M, et al. Pseudomonas cepacia infection in cystic fibrosis: an emerging problem. J Pediatr. Feb 1984;104(2):206-10. [Medline].
Kang CI, Kim SH, Park WB, et al. Clinical features and outcome of patients with community-acquired Pseudomonas aeruginosa bacteraemia. Clin Microbiol Infect. May 2005;11(5):415-8. [Medline].
Karlowicz MG, Buescher ES, Surka AE. Fulminant late-onset sepsis in a neonatal intensive care unit, 1988- 1997, and the impact of avoiding empiric vancomycin therapy. Pediatrics. Dec 2000;106(6):1387-90. [Medline].
Kerem E. The Role of Pseudomonas aeruginosa in the Pathogenesis of Lung Disease in Cystic Fibrosis: More Questions than Answers. Pediatric Pulmonology- Supplement. 1997;14:403-11.
Komshian SV, Tablan OC, Palutke W, Reyes MP. Characteristics of left-sided endocarditis due to Pseudomonas aeruginosa in the Detroit Medical Center. Rev Infect Dis. Jul-Aug 1990;12(4):693-702. [Medline].
Koprnova J, Beno P, Korcova J, et al. Bacteremia due to Pseudomonas aeruginosa: results from a 3-year national study in the Slovak Republic. J Chemother. Oct 2005;17(5):470-6. [Medline].
Lahiri T. Approaches to the treatment of initial Pseudomonas aeruginosa infection in children who have cystic fibrosis. Clin Chest Med. Jun 2007;28(2):307-18. [Medline].
Malaty J, Lee JC, Zhang M, et al. Click here to read Hearing loss and extent of labyrinthine injury in Pseudomonas otitis media. Malaty J, Lee JC, Zhang M, Stevens G, Antonelli PJ. Department of Otolaryngology, University of Florida, Gainesville 32610-0264, USA. Otolaryngol Head Neck Surg. Jan 2005;132(1):25-9. [Medline].
Malaty J, Lee JC, Zhang M, et al. Hearing loss and extent of labyrinthine injury in Pseudomonas otitis media. Otolaryngol Head Neck Surg. Jan 2005;132(1):25-9. [Medline].
Marchetti F, Bua J. More evidence is needed in the antibiotic treatment of Pseudomonas aeruginosa colonisation. Arch Dis Child. Nov 2005;90(11):1204. [Medline].
Masekela R, Green RJ. The role of macrolides in childhood non-cystic fibrosis-related bronchiectasis. Mediators Inflamm. 2012;2012:134605. [Medline]. [Full Text].
Medical Letter. Drugs for sexually transmitted infections. Med Lett Drugs Ther. Sep 24 1999;41(1062):85-90. [Medline].
Medical Letter. The choice of antibacterial drugs. Med Lett Drugs Ther. Oct 22 1999;41(1064):95-104. [Medline].
Milner SM. Acetic acid to treat Pseudomonas aeruginosa in superficial wounds and burns. Lancet. Jul 4 1992;340(8810):61. [Medline].
Morrison AJ Jr, Wenzel RP. Epidemiology of infections due to Pseudomonas aeruginosa. Rev Infect Dis. Sep-Oct 1984;6 Suppl 3:S627-42. [Medline].
Mukhopedhyay S, Singh M, Cater JI. Nebulized antipseudomonal antibiotic therapy in cystic fibrosis: A meta-analysis of benefits and risks. Thorax. 1996;51:364.
Mull, CC. Case Report: Ecthyma gangrenosum as a Manifestation of Pseudomonas Sepsis in a Previously Healthy Child. Annals Emerg Med. Oct 2000;36:4.
Nagaki M, Shimura S, Tanno Y, et al. Role of chronic Pseudomonas aeruginosa infection in the development of bronchiectasis. Chest. Nov 1992;102(5):1464-9. [Medline].
Neo EN, Haritharan T, Thambidorai CR, Suresh V. Pseudomonas necrotizing fasciitis in an immunocompetent infant. Pediatr Infect Dis J. Oct 2005;24 (10):942-3. [Medline].
Obritsch MD, Fish DN, MacLaren R, Jung R. Nosocomial infections due to multidrug-resistant Pseudomonas aeruginosa: epidemiology and treatment options. Pharmacotherapy. Oct 2005;25(10):1353-64. [Medline].
Pandey A, Malenie R, Asthana AK. Beta-lactamase producing Pseudomonas aeruginosa in hospitalised patients. Indian J Pathol Microbiol. Oct 2005;48(4):530-3. [Medline].
Paul M, Leibovici L. Combination antibiotic therapy for Pseudomonas aeruginosa bacteraemia. Lancet Infect Dis. Aug 2004;4(8):519-27. [Medline].
Radford R, Brahma A, Armstrong M, Tullo AB. Severe sclerokeratitis due to Pseudomonas aeruginosa in noncontact-lens wearers. Eye. Feb 2000;14 (Pt 1):3-7. [Medline].
Rajashekaraiah KR, Rice TW, Kallick CA. Recovery of Pseudomonas aeruginosa from syringes of drug addicts with endocarditis. J Infect Dis. Nov 1981;144(5):482. [Medline].
Roilides E, Butler KM, et al. Pseudomonas Infections in Children with Human Immunodeficiency Virus Infection. Pediatric Infect Dis J. 1992;11:547-53.
Saiman L. The use of macrolide antibiotics in patients with cystic fibrosis. Curr Opin Pulm Med. Nov 2004;10(6):515-23. [Medline].
Schimpff SC, Moody M, Young VM. Relationship of colonization with Pseudomonas aeruginosa to development of Pseudomonas bacteremia in cancer patients. Antimicrobial Agents Chemother. 1970;10:240-4. [Medline].
Tabbara KF, El-Sheikh HF, Aabed B. Extended wear contact lens related bacterial keratitis. Br J Ophthalmol. Mar 2000;84(3):327-8. [Medline].
Tablan OC, Chorba TL, Schidlow DV, et al. Pseudomonas cepacia colonization in patients with cystic fibrosis: risk factors and clinical outcome. J Pediatr. Sep 1985;107(3):382-7. [Medline].
Taneja N, Meharwal SK, Sharma SK, Sharma M. Significance and characterisation of pseudomonads from urinary tract specimens. J Commun Dis. Mar 2004;36(1):27-34. [Medline].
Tsekouras AA, Johnson A, Miller G, Orton HI. Pseudomonas aeruginosa necrotizing fasciitis: a case report. J Infect. Sep 1998;37(2):188-90. [Medline].
Tumaliuan JA, Stambouly JJ, Schiff RJ, et al. Pseudomonas pericarditis and tamponade in an infant with human immunodeficency virus infection. Arch Pediatr Adolesc Med. Feb 1997;151(2):207-8. [Medline].
Whitehead B, Helms P, Goodwin M, et al. Heart-lung transplantation for cystic fibrosis. 2: Outcome. Arch Dis Child. Sep 1991;66(9):1022-6; discussion 1016-7. [Medline].
Wu BY, Peng CT, Tsai CH, Chiu HH. Community-acquired Pseudomonas aeruginosa bacteremia and sepsis in previously healthy infants. Acta Paediatr Taiwan. Jul-Aug 1999;40(4):233-6. [Medline].
Yeung CK, Lee KH. Community acquired fulminant Pseudomonas infection of the gastrointestinal tract in previously healthy infants. J Paediatr Child Health. Dec 1998;34(6):584-7. [Medline].

