Não fermentadores

Acinetobacter lwoffii

Gram-negative coccobacilli that decolorise poorly

Identification & Growth

Identification

Oxidase-negative, non-motile, non-saccharolytic (does not acidify glucose)

Growth Conditions

Blood agar and MacConkey, non-pigmented colonies, 35 °C, 24 h

Clinical Significance

Skin flora; catheter-related bacteremia and blood culture contamination

Intrinsic Resistance

Intrinsic resistance to ampicillin, amoxicillin-clavulanate, first/second-generation cephalosporins, ertapenem, aztreonam, fosfomycin and fusidic acid

Bench Alerts

Much more susceptible than A. baumannii — do not extrapolate the baumannii complex profile

Clinical Notes

Clinical presentations

Catheter-associated bacteremia, usually with a milder course than that caused by the A. baumannii complex.
Catheter-associated urinary infection and, rarely, post-neurosurgical meningitis.
It frequently represents skin colonization or specimen contamination, requiring clinical correlation.

Specimens and collection

Paired blood cultures to assess clinical significance; a single positive bottle rarely indicates infection.
Quantitative urine culture recording the collection method (midstream, in-and-out or indwelling catheter).
Semiquantitative catheter-tip culture when there are local signs of access infection.

Epidemiology and at-risk populations

It colonizes normal human skin and moist environments, being the Acinetobacter most often found outside hospitals.
Invasive cases concentrate in patients with devices and immunosuppression.
Unlike the baumannii complex, it rarely takes part in multidrug-resistance outbreaks.

Resistance and therapeutic implications

It is usually far more susceptible than A. baumannii, with good beta-lactam and aminoglycoside activity.
The genus is intrinsically resistant to ertapenem, aztreonam and narrow-spectrum penicillins.
Interpret the antibiogram using the Acinetobacter spp. criteria in the current BrCAST/EUCAST document.

Bench and reporting notes

Oxidase-negative, non-motile, non-fermenting Gram-negative coccobacillus that grows on MacConkey without fermenting lactose.
It does not grow at 44 °C and is non-saccharolytic, which helps separate it from the A. baumannii complex at the bench.
State in the report when the isolate is consistent with colonization, avoiding unnecessary treatment.

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 Acinetobacter lwoffii in the lab?

Acinetobacter lwoffii is identified through oxidase-negative, non-motile, non-saccharolytic (does not acidify glucose).

What are the intrinsic resistances of Acinetobacter lwoffii?

This organism is naturally resistant to intrinsic resistance to ampicillin, amoxicillin-clavulanate, first/second-generation cephalosporins, ertapenem, aztreonam, fosfomycin and fusidic acid. These drugs should not be reported as susceptible.

Where is Acinetobacter lwoffii commonly found?

It is typically associated with skin flora; catheter-related bacteremia and blood culture contamination.

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