Nonfermenters

Phenotypic Characteristics

Gram-Negative bacilli

Do not ferment glucose 

Variable growth on MacConkey agar (MAC)

Oxidase Variable (majority Oxidase Positive)

Nitrate Variable

Genus Pseudomonas

(Family Pseudomonadaceae)

Motile by one or more polar flagella; Straight or slightly curved Gram-Negative Bacili

Catalase Positive

Oxidase Positive

Non-lactose fermenters on MAC

Nitrate Positive

O-F Glucose Positive

Pseudomonas aeruginosa

Leading cause of pneumonia

Motile; Slight or slightly curved, slender Gram-Negative Rods

O-F Glucose Positive; oxidize rather than ferment D-glucose

Colonies spreading and flat with a Pearl-like sheen (pearlescent/metallic)

Grape-like odor

Catalase Positive

Oxidase Positive

Growth at 42°C

Genus Burkholderia

Motile, Gram-Negative Bacilli

Catalase Positive

Growth on MAC

Burkholderia cepacia

Motile, Gram-Negative bacillus

One of the most drug-resistant organisms encountered in the CML

Nonfermenter (Does not ferment glucose); Bright Pink colonies on MAC due to lactose oxidation

Oxidase Positive

Positive for Lysine decarboxylation

Saccharolytic with OF Glucose Positive, OF Xylose Positive, OF Lactose Positive, OF Sucrose Positive                                       

Burkholderia pseudomallei

Motile, short, Gram-Negative bacillus having a bipolar or safety pin appearance

Nonfermenter (Does not ferment glucose) 

Non-lactose Fermenter on MAC 

Saccharolytic (OF Glucose Positive); OF Lactose Positive

Arginine dihydrolase Positive    

Gas from Nitrate Positive

Lysine decarboxylase Negative

Oxidase Positive

Nitrate Positive

Produces a pronounced earthy odor 

Stenotrophomonas maltophilia

Motile;Short to medium-size, straight Gram-Negative Rods having rough, dull yellow, dark tan, or lavender-green with ammonia odor

Glucose oxidizer (OF Glucose Positive; Strong Maltose Oxidizer (OF Maltose Positive)

Oxidase Negative

DNase Positve (unlike most glucose oxidizing GNB)

Lysine decarboxylase Positive (unlike most glucose oxidizing GNB)

Resistant to most antibiotics EXCEPT  trimethoprim-sulfamethoxazole

 Alcaligenes faecalis

Motile by peritrichous flagella

Produce white colonies having a thin, spreading, irregular edge and a green-apple odor

Oxidase Positive

Indole Negative

Asaccharolytic fermenter

Reduces Nitrite but not Nitrate

Pseudomonas fluorescens

No distinctive colony morphology on sheep blood agar

No pyocyanin production (no sheen or metallic colonies)

No growth at 42°C

Liquefies Gelatin

Pseudomonas putida

No distinctive colony morphology on sheep blood agar

No pyocyanin production (no sheen or metallic colonies)

No Growth at 42°C

Does not liquify Gelatin

Acinetobacter

Non-Motile; Gram-Negative coccobacillary rods

Can be either:

Oxidizes rather than ferments D-Glucose (OF Glucose Positive)

OR
Neither Oxidizes nor ferments D-Glucose (OF Glucose Negative)

Non-Lactose fermenter; on MAC distinctive pinkish hue 

Oxidase Negative

Acinetobactor Species

A. baumannii = OF Glucose Positive; OF Lactose Positive; Non-hemolytic

A. haemolyticus = OF Glucose Negative; OF Lactose Negative; Beta-Hemolytic

A. lwoffii = OF Glucose Negative; OF Lactose Negative; Non-hemolytic

Pseudomonas stutzeri

Gram-Negative Rods forming dry, wrinkled colonies on blood agar

Oxidase Positive

OF Glucose Positive; OF Lactose Negative

Arginine dihydrolase Negative

Ability to grow in 6.5% NaCl broth

Gas from Nitrate

Moraxella

Gram-Negative or Gram-Variable diplococci, forming small colonies on blood agar that are smooth, translucent to semiopaque; occasional strains showing pitting of agar

Non-Motile

Oxidase Positive

Indole Negative

Assacharolytic

Psychrobacter (Moraxella) phenylpyruvicus

VERSUS

Brucella

                          Brucella                               P. phenylpyruvicus

Oxidase                  --                                                 --

Motility                   --                                                 --

Urease                   +                                                  +

Gram Stain        tiny coccobacilli                             broad diplococci

OF Xylose               +                                                  --      

PDA                      --                                                    +

Brucella also OF Glucose Positive;                      P. phenylpyruvicus is uniformly assacharolytic

Achromobacter xylosoxidans

Motile

Saccharolytic Non-Fermenter

Oxidase Positive                                          Citrate Positive

Indole Negative                                             Urease Negative

OF Glucose Positive

OF Xylose Positive

OF Negative for: Mannitol, lactose, sucrose, and maltose

Nitrate Reduction Positive (60% gas producing)