Não fermentadores

Achromobacter xylosoxidans

Non-fermenting Gram-negative bacilli

Identification & Growth

Identification

Oxidase-positive, motile by peritrichous flagella, oxidizes xylose
Confirmation by MALDI-TOF

Growth Conditions

MacConkey agar-positive, blood agar 35 °C, 24–48 h; greyish colonies

Clinical Significance

Colonization in cystic fibrosis, catheter-related bacteremia, post-surgical infection

Intrinsic Resistance

Resistant to aztreonam, first- and second-generation cephalosporins and aminoglycosides

Bench Alerts

Piperacillin-tazobactam, meropenem and trimethoprim-sulfamethoxazole are the usual options
Do not extrapolate Pseudomonas breakpoints

Clinical Notes

Clinical presentations

Catheter-related bacteremia, ventilator-associated pneumonia and surgical-site infection in the hospital setting.
Chronic airway colonization in cystic fibrosis and bronchiectasis, associated with functional decline.
Peritonitis in peritoneal dialysis and post-procedure ocular infection, usually linked to a water source.

Specimens and collection

Blood culture, peritoneal fluid, sputum/tracheal aspirate or bronchoalveolar lavage according to the suspected site.
In cystic fibrosis, plate on selective media for non-fermenters to avoid overgrowth by P. aeruginosa.
Investigate water, solutions and diluted disinfectants when cases cluster.

Epidemiology and at-risk populations

It inhabits hospital water reservoirs and tolerates chlorhexidine and other disinfectants at inadequate concentrations.
Greater risk in cystic fibrosis, haematological malignancy, transplantation and prolonged device use.
Reported in common-source outbreaks, with documented cross-transmission between patients.

Resistance and therapeutic implications

Intrinsic resistance to aztreonam and to extended-spectrum cephalosporins (including ceftriaxone and cefotaxime), with reduced aminoglycoside susceptibility.
Piperacillin-tazobactam, ceftazidime, meropenem and trimethoprim-sulfamethoxazole are the usual active options, always confirmed by testing.
EUCAST/BrCAST criteria are limited: when absent, use MIC with non-species-related PK/PD criteria and state the method in the report.

Bench and reporting notes

Oxidase-positive, catalase-positive Gram-negative rod that oxidizes xylose and is motile by peritrichous flagella.
Frequently confused with Pseudomonas and Burkholderia on biochemical systems; confirm with MALDI-TOF.
Include the intrinsic-resistance alert in the report to prevent prescription of a third-generation cephalosporin.

Sources

Educational decision-support content. It does not replace laboratory validation, current guidelines or review by the responsible professional.

FAQ: Frequently Asked Questions

How to identify Achromobacter xylosoxidans in the lab?

Achromobacter xylosoxidans is identified through oxidase-positive, motile by peritrichous flagella, oxidizes xylose, confirmation by maldi-tof.

What are the intrinsic resistances of Achromobacter xylosoxidans?

This organism is naturally resistant to resistant to aztreonam, first- and second-generation cephalosporins and aminoglycosides. These drugs should not be reported as susceptible.

Where is Achromobacter xylosoxidans commonly found?

It is typically associated with colonization in cystic fibrosis, catheter-related bacteremia, post-surgical infection.

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