This is the most commonly isolated non-fermentative bacilli
Pseudomonas
What are the most appropriate screening tests to presumptively differentiate and identify the nonfermentative gram-negative bacilli (NFB) from the Enterobacteriaceae species?
Oxidase
TSI
nitrate reduction
growth on MacConkey agar
Presumptive tests used for identification of the Pseudomonas spp. are:
Oxidase, oxidation–fermentation (OF) glucose (open)
OF glucose (sealed)
Motility
Pigment production
Which tests are most appropriate to differentiate between Pseudomonas aeruginosa and Pseudomonas putida?
Mannitol
Nitrate reduction
Growth at 42°C
Which test group best differentiates Acinetobacter spp. from P. aeruginosa?
Oxidase
Motility
Nitrate reduction
In addition to motility, which test best differentiates Acinetobacter spp. and Alcaligenes faecalis?
Oxidase
The most noted differences between P. aeruginosa and Stenotrophomonas maltophilia are:
Oxidase
42°C growth
Polar tuft of flagella
Which nonfermentative bacillus is usually associated with a lung infection related to cystic fibrosis (CF)?
Pseudomonas aeruginosa
A nonfermenter recovered from an eye wound is oxidase positive, motile with polar monotrichous flagella, and grows at 42°C. Colonies are dry, wrinkled or smooth, buff to light brown, and are difficult to remove from the agar. In which DNA homology group should this organism be placed?
Pseudomonas stutzeri
Which organism is associated with immunodeficiency syndromes and melioidosis (a glanders-like disease prevalent in Southeast Asia and northern Australia)?
Burkholderia pseudomallei
Which characteristics/biochemical tests are used to differentiate Burkholderia cepacia from S. maltophilia?
Pigment on blood agar, oxidase, DNase
Alcaligenes faecalis (formerly A. odorans) is distinguished from Bordetella bronchiseptica with which test?
Urease (rapid)
Chryseobacterium spp. are easily distinguished from Acinetobacter spp. by which of the following two tests?
Oxidase, growth on MacConkey agar
A gram-negative coccobacillus was recovered on chocolate agar from the CSF of an immunosuppressed patient. The organism was nonmotile and positive for indophenol oxidase but failed to grow on MacConkey agar. The organism was highly susceptible to penicillin. The most probable identification is:
Moraxella lacunata
Cetrimide agar is used as a selective isolation agar for which organism?
Pseudomonas aeruginosa
A yellow pigment–producing organism, growing on chocolate agar, testing oxidase positive, nonmotile and does not grow on MacConkey agar was recovered from the blood of a neonate. What is the most likely organism?
Elizabethkingia (formerly Chryseobacterium) meningosepticum
Which reagent(s) is (are) used to develop the red color indicative of a positive reaction in the nitrate reduction test?
Sulfanilic acid and α-naphthylamine
Chryseobacterium spp. and B. cepacia are easily differentiated by which test?
Motility
Which of the listed Pseudomonas spp. is associated with the following virulence factors: exotoxin A, endotoxins, proteolytic enzymes, antimicrobial resistance, and production of alginate?
Pseudomonas aeruginosa
A 20-year-old horse groomer exhibited a “glanders-like” infection. His history indicated he had suffered several open wounds on his hands 2 weeks before the swelling of his lymph nodes. A gram-negative rod was recovered from a blood culture that grew well on blood and MacConkey agars. Most of the biochemical tests were negative, including the cytochrome oxidase test. What is the most likely identification?
Burkholderia mallei
A Vietnam War veteran presented with a “glanders-like” infection (melioidosis). Several blood cultures produced gram-negative rods that were positive for cytochrome oxidase, oxidized glucose and xylose, and grew at 42°C. What is the most likely organism?
Burkholderia pseudomallei
Cytochrome oxidase-positive, nonfermentative gram-negative bacilli were recovered from the stool of a patient with CF. The isolates produced wet (mucoidy) light blue colonies on tryptic soy agar. Which identification is most likely?
Pseudomonas aeruginosa
Several postoperative hospitalized patients were colonized with gram-negative coccobacilli growing on MacConkey agar. Specimens were obtained from blood, urine, and wound sites. Testing revealed oxidase negative, nonmotile organisms. Which of the following is the most likely cause of the nosocomial infections?
Acinetobacter spp.
Where is Pseudomonas usually found?
Cosmetics, swimming pools, hot tubs, clothing, footwear
