Pseudomonas is a small gram-negative bacillus that produces nosocomial infections, superinfections of various parts of the body, and a rare disease called melioidosis. This bacillus is also associated with bacteremia, endocarditis, and osteomyelitis in drug addicts.
Treatment of local Pseudomonas infection is usually successful and complications are rare. However, in patients with poor immunologic resistance — premature infants, elderly patients, or those with debilitating disease, burns, or wounds — septicemic Pseudomonas infections are serious and sometimes fatal.
The most common species of Pseudomonas is P. aeruginosa. Other species that typically cause disease in humans include P. acidovorans, P. alcaligenes, P cepacia, P. fluorescens, P. maltophilia, P. putida, P. putrefaciens, P. stutzeri, and P. testosteroni.
These organisms are commonly found in hospital liquids that have been allowed to stand for a long time, such as benzalkonium chloride, hexachlorophene soap, saline solution, penicillin, water in flower vases, and fluids in incubators, humidifiers, and respiratory therapy equipment.
In elderly patients, Pseudomonas infection usually enters through the genitourinary tract; in infants through the umbilical cord, skin, and GI tract.
The most common infections associated with Pseudomonas include skin infections (such as burns and pressure ulcers), urinary tract infections, infant epidemic diarrhea and other diarrheal illnesses, bronchitis, pneumonia, bronchiectasis, meningitis, corneal ulcers, mastoiditis, otitis externa, otitis media, endocarditis, and bacteremia.
Drainage in these infections has a distinct, sickly sweet odor and a greenish-blue pus that forms a crust on wounds. Other signs and symptoms depend on the site of infection. For example, when it invades the lungs, Pseudomonas causes pneumonia with fever, chills, and a productive cough.
Diagnosis requires isolation of the Pseudomonas organism in blood, spinal fluid, urine, exudate, or sputum culture.
In the debilitated or otherwise vulnerable patient with clinical evidence of Pseudomonas infection, treatment should begin immediately, even before the results of laboratory tests are received.
Antibiotic treatment includes aminoglycosides, such as gentamicin or tobramycin, combined with a Pseudo-monas-sensitive penicillin, such as carbenicillin disodium or ticarcillin. An alternative combination is amikacin and a similar penicillin. Such combination therapy is necessary because Pseu-domonas quickly becomes resistant to carbenicillin alone.
CLINICAL TIP: In bacteremia, an aminoglycoside and beta-lactam antibiotic with anti-Pseudo-monals activity increases survival rates.
In urinary tract infections, carbenicillin indanyl sodium can be used alone if the organism is susceptible and the infection doesn’t have systemic effects; it’s excreted in the urine and builds up high urine levels that prevent resistance.
Local Pseudomonas infections or septicemia secondary to wound infection require 1% acetic acid irrigations, topical application of colistimethate sodium and polymyxin B, and debridement or drainage of the infected wound.
❑ Observe and record the character of wound exudate and sputum.
❑ Before administering antibiotics, ask the patient about a history of allergies, especially to penicillin.
CLINICAL TIP: If combinations of carbenicillin or ticarcillin and an aminoglycoside are ordered, schedule the doses 1 hour apart (carbenicillin and ticarcillin may decrease the antibiotic effect of the aminoglycoside). Don’t give both antibiotics through the same administration set.
❑ Monitor the patient’s renal function (urine output, blood urea nitrogen, specific gravity, urinalysis, and creatinine) during treatment with aminoglycosides.
❑ Protect immunocompromised patients from exposure to this infection. Attention to hand washing and aseptic techniques prevent further spread.
❑ To prevent Pseudomonas infection, maintain proper endotracheal and tracheostomy suctioning technique: Use strict sterile technique when caring for I.V. lines, catheters, and other tubes; properly dispose of suction bottle contents; and label and date solution bottles and change them frequently, according to policy.
Review other book chapters online related to Melioidosis:
Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: Handbook of Diseases Authors: Springhouse Publisher: Lippincott Williams & Wilkins Copyright: 2003 ISBN: 1-58255-266-5 
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