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Infectious Diseases

Alcoligenes xylosoxidans



I am trying to find information on a apparently rare bacteria organism called Alcaligenes xylosoxidans that I have been infected with. The only information I have so far is the microbiology culture report my docter gave me and what little info there is, I find disturbing. If you could help me understand what this bacteria is, I may understand how I caught this nasty infection and channel my energy to fight it.


Here is some information from Mandell`s textbook of Infectious Diseases that may be of help.


Organisms of the Alcaligenes genus are another group of nonfermenting gram-negative bacilli found in soil and water. They can also be recovered from the human respiratory tract and gastrointestinal tract in hospitalized patients. Infection results when they are introduced into wounds or colonize those with compromised host defenses. Three clinically relevant species are described: Alcaligenes xylosoxidans, which has two subspecies: xylosoxidans (the organism formerly known as Achromobacter xylosoxidans) and denitrificans; Alcaligenes faecalis (the former Alcaligenes odorans); and Alcaligenes piechaudii. Xylosoxidans subsp. xylosoxidans (sometimes called Achromobacter xylosoxidans) is the most clinically important of these organisms. It probably is part of the endogenous flora of the ear and gastrointestinal tract and is a common contaminant of fluids. The organism has been implicated in outbreaks of nosocomial infection associated with contaminated solutions (intravenous fluids, hemodialysis fluid, irrigation fluids, mouthwash, etc.), pressure transducers, incubators and humidifiers, and contaminated soaps and disinfectants. Contamination of well water used by the patient was documented in one case of bacteremia. Clinical illness that is due to A. xylosoxidans subsp. xylosoxidans has involved isolates from blood, peritoneal and pleural fluids, urine, respiratory secretions, and wound exudates. Bacteremia, often related to intravascular catheters, is the most commonly reported infection. Biliary tract sepsis, meningitis (sometimes with lymphocytic predominance in cerebrospinal fluid), pneumonia (nosocomial and community-acquired), peritonitis, urinary tract infection, osteomyelitis, prosthetic knee infection, and prosthetic valve endocarditis have been reported. Patients often have an immunosuppressed state such as but this is not always the case, especially in nosocomial outbreaks. This organism can colonize the airways of patients with cystic fibrosis and has been associated with exacerbation of respiratory symptoms. Recovery in neonatal infection may result from perinatal transfer from the mother. The organism has been recovered from eye, ear, and pharynx, but its pathogenic potential in these sites is unproved.

Strains of A. xylosoxidans subsp. xylosoxidans grow well on blood agar and MacConkey`s agar plates; they produce flat, spreading and rough colonies and have peritrichous flagellae, features that help distinguish them from pseudomonads. The organisms are oxidase-positive, are catalase-positive, oxidize glucose to produce acid, and (as the species name indicates) oxidize xylose readily. An isolate of A. xylosoxidans subsp. xylosoxidans can easily be mistaken for a non-aeruginosa strain of Pseudomonas, but the unusual susceptibility pattern suggests the correct identity.

Usually, strains of A. xylosoxidans subsp. xylosoxidans are susceptible to trimethoprim-sulfamethoxazole, ureidopenicillins, imipenem, ceftazidime, cefoperazone, and b-lactamase inhibitor combinations. Generally, they are resistant to narrow-spectrum penicillins, other cephalosporins (including cefotaxime and ceftriaxone), aztreonam, and aminoglycosides. Susceptibility to the fluoroquinolones is variable. Hyperproduction of b-lactamases has been implicated in resistance.

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Response by:

Gary   Roselle, MD Gary Roselle, MD
Professor of Clinical Medicine
College of Medicine
University of Cincinnati