Pseudomonas Infections
A genus of small, gram-negative bacilli, Pseudomonas primarily produces nosocomial infections, superinfections of various parts of the body, and a rare disease called melioidosis. The most common infections associated with Pseudomonas include skin infections (such as burns and pressure ulcers), urinary tract infections (UTIs), infant epidemic diarrhea and other diarrheal illnesses, bronchitis, pneumonia, bronchiectasis, meningitis, corneal ulcers, mastoiditis, otitis externa, and otitis media. This bacillus is especially associated with bacteremia, endocarditis, and osteomyelitis in drug addicts.
In local Pseudomonas infections, treatment is usually successful and complications are rare. However, in patients with poor resistance to infection—for example, premature infants, elderly people, and persons with debilitating disease, burns, or wounds—septicemic Pseudomonas infections are considered serious. In some patients they may even cause death. (See Melioidosis, page 754.)
Causes
The most common species of Pseudo-monas is P. aeruginosa. Other pathogenic species include P. maltophilia, P. cepacia,
P. fluorescens, P. testosteroni, P. acidovorans, P. alcaligenes, P. stutzeri, P. putrefaciens, and P. putida.
P. fluorescens, P. testosteroni, P. acidovorans, P. alcaligenes, P. stutzeri, P. putrefaciens, and P. putida.
Melioidosis
Wound penetration, inhalation, or ingestion of the gram-negative bacterium Pseudomonas pseudomallei causes melioidosis. Once confined to Southeast Asia, Central America, South America, Madagascar, and Guam, incidence in the United States is rising because of the recent influx of Southeast Asian immigrants.
Two forms: Chronic and acute
Melioidosis occurs in two forms: chronic melioidosis, which causes osteomyelitis and lung abscesses; and acute melioidosis (rare), which causes pneumonia, bacteremia, and prostration. Acute melioidosis is commonly fatal. Most infections are chronic, however, and produce clinical symptoms only with accompanying malnutrition, major surgery, or severe burns.
Diagnostic measures consist of isolation of P. pseudomallei in a culture of exudate, blood, or sputum; serology tests (complement fixation, passive hemagglutination); and chest X-ray, with findings that resemble tuberculosis.
Treatment includes ceftazidime for clinical disease; alternatives are co-trimoxazole, cefotaxime, imipenem, and amoxicillin-clavulanate. Acute pulmonary infections are treated for up to 150 days for acute illness and longer for chronic conditions. In addition, surgical drainage of abscesses and other aggressive treatment of septicemia may be necessary. Most cases are curable if treated appropriately, but septic infection continues to have a high mortality rate.
These organisms frequently are found in hospital liquids that have been allowed to stand for a long time, such as benzalkonium chloride, hexachlorophene soap, saline solution, water in flower vases, and fluids in incubators, humidifiers, and respiratory therapy equipment. Outside the hospital, Pseudomonas skin infections have been associated with the use of contaminated whirlpools, hot tubs, spas, and swimming pools.
In elderly patients, Pseudomonas infection usually enters through the genitourinary tract.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
