1Q: What are the general Gram stain and structural characteristics of these organisms?
A: Gram negative, non-spore forming bacteria that may appear as rods, coccobacilli, or diplococci (some Acinetobacter and Moraxella).
2Q: What is the oxygen requirement of these organisms?
A: Obligate aerobes.
3Q: Under what condition may these organisms grow anaerobically?
A: They may grow anaerobically under the presence of nitrate.
4Q: How do these organisms grow on blood agar plate (BAP)?
A: Good growth on BAP at 24 hours.
5Q: Do these organisms ferment glucose?
A: No, glucose is not fermented.
6Q: How is glucose utilized by these organisms?
A: Glucose is utilized via oxidative metabolism of carbohydrates instead of fermentative metabolism.
7Q: What is the natural habitat of these organisms?
A: Water, soil, and plants, with humans serving as a transient habitat.
8Q: What type of pathogens are these organisms classified as?
A: Opportunistic pathogens.
9Q: Where are these organisms commonly found and how are they transferred to patients?
A: They are saprophytes found on food, water, and soil, and are transferred to patients by ingestion of foods, nosocomial infections, and medical devices.
10Q: From what sources can these organisms be isolated?
A: Blood, CSF, urine, wounds, bites, burns, eyes, ears, animals, and the environment.
11Q: What percentage of all gram negative bacteria isolated in clinical labs are nonfermenters?
A: 15%.
12Q: What are the three most common pathogens listed?
A:
Pseudomonas aeruginosa
Acinetobacter species (most common: A. baumannii)
Stenotrophomonas maltophilia
13Q: What are the special considerations for NFB media regarding peptone and carbohydrate?
A: Peptone: Carbohydrate ratio 0.2:1 with 0.3% agar.
14Q: Why is decreased peptone used in the media?
A: Decreased peptone in media minimizes oxidative products formation (which can elevate pH and neutralize/mask weak acid produced from oxidation).
15Q: Why is semisolid media used for NFB testing?
A: Semisolid media prevents dilution/diffusion of acid produced and keeps it concentrated at the site of production.
16Q: What is the general incubation temperature for NFB media?
A: 30°C.
17Q: What must be considered when selecting an indicator for NFB media?
A: Choose an indicator that can detect change to acid at higher pH.
18Q: Why must the indicator detect acid at higher pH in NFB media?
A: Because nonfermenters produce weak/small amounts of acid.
19Q: What is the acid and alkaline pH range for Bromothymol blue?
A: Acid: 6.0
Alkaline: 7.6
20Q: What is the acid and alkaline pH range for Bromocresol purple?
A: Acid: 5.2
Alkaline: 6.8
21Q: What is the acid and alkaline pH range for Phenol Red?
A: Acid: 6.8
Alkaline: 8.4
22Q: What is the acid and alkaline pH range for Methyl red?
A: Acid: 4.4
Alkaline: 6.0
23Q: What is the purpose of the Oxidative/Fermentation (O/F) Glucose Test?
A: To determine if an organism can metabolize sugar (glucose).
24Q: How is the O/F glucose test set up?
A:
Stab 2 media with test organism to ¼ of the bottom
Overlay ONE tube with mineral oil and leave the other uncovered
25Q: What does it mean if both tubes turn yellow? [O/F] Glucose Test
A: Production of acid → glucose fermentation (anaerobic process)
26Q: What does it mean if only the uncovered tube turns yellow? [O/F] Glucose Test
A: Glucose oxidation
27Q: What does it mean if neither tube turns yellow and the open tube turns blue?
[O/F] Glucose Test
A: Not utilizing glucose. Peptone used.
28Q: Which organisms are motile with polar flagella (oxidase positive)?
A: Pseudomonas, Burkholderia, Ralstonia, Cupriavidus, Pandoraea, Methylobacterium, Roseomonas
29Q: Which organisms are motile with peritrichous flagella (oxidase positive)?
A:
Alcaligenes, Bordetella, Achromobacter, Oligella ureolytica, Rhizobium, Ochrobactrum
30Q: Which organisms are non-motile and oxidase positive?
A:
Bergeyella, Chryseobacterium, Empedobacter, Flavobacterium, Myroides, Riemerella, Weeksella, Sphingobacterium, Moraxella, Psychrobacter, Oligella urethralis
31Q: Which organisms are non-motile and oxidase negative?
A:
Acinetobacter, non-fastidious Bordetella such as Bordetella homesii and parapertussis, Kesteria gyiorum
32Q: Which organisms are oxidase +, motility +, polar flagella?
Fluorescent Pseudomonas
Stutzeri group
Pseudomallei group – all members are colistin and polymyxin B resistant
Stenotrophomonas maltophilia
Shewanella putrefaciens/algae
33Q: Which organisms are fluorescent Pseudomonas (oxidase +, motility +, polar flagella)?
A:
Pseudomonas aeruginosa
Pseudomonas fluorescens
Pseudomonas putida
34Q: Which organism is in the Stutzeri group?
A:
Pseudomonas stutzeri
35Q: What characterizes the Pseudomallei group?
A:
All members are colistin and polymyxin B resistant
Members:
Burkholderia cepacia
Burkholderia pseudomallei
Burkholderia mallei – motility NEG
36Q: What is important about Stenotrophomonas maltophilia?
A:
Oxidase NEG
37Q: Which organisms are exceptions and are oxidase negative and yellow pigmented?
A:
Pseudomonas oryzihabitans
Pseudomonas luteola
38Q: What pigment do all fluorescent Pseudomonas produce?
A:
Water-soluble yellow pigment pyoverdin
Pyoverdin = fluorescein that fluoresces blue-green under long-wave UV light
39Q: What enzyme result do ALL fluorescent Pseudomonas share?
A:
All ADH (+)
40Q: What are the characteristics of Pseudomonas fluorescens?
A:
Growth at 42°C (−)
Growth at 4°C (+)
Gelatin (+)
41Q: What are the characteristics of Pseudomonas putida?
A:
Growth at 42°C (−)
Growth at 4°C (−)
Gelatin (−)
42Q: What pigments does Pseudomonas aeruginosa produce?
A:
Produces pyocyanin in addition to pyoverdin
Pyocyanin = non-fluorescent water-soluble blue pigment
(Yellow pyoverdin + blue pyocyanin = green pigment)
43Q: What are the growth characteristics of Pseudomonas aeruginosa?
A:
Growth at 42°C (+)
Flat, rough, granular, spreading colonies (some strains beta-hemolytic)
Grape/corn tortilla odor
Fluoresces yellow-green under UV light
Metallic sheen
Mucoid colonies in cystic fibrosis patients
44Q: What are the biochemical characteristics of Pseudomonas aeruginosa?
A:
Oxidase (+)
Acetamide (+)
45Q: What is Pseudomonas aeruginosa most commonly identified as?
A:
Most commonly isolated nonfermenter
46Q: What are the virulence factors of Pseudomonas aeruginosa?
A:
Exotoxins, endotoxins, and proteolytic enzymes (elastases, collagenases)
47Q: What is Pseudomonas aeruginosa intrinsically resistant to?
A:
Multiple antimicrobials including:
Ampicillin, Amp/Sulb, Amox/Clav, ceftriaxone, ertapenem, SXT, etc.
48Q: What are the nosocomial infections associated with Pseudomonas aeruginosa?
A:
RT, UTI, wounds (burns), blood, CNS
49Q: What community-acquired infections are associated with Pseudomonas aeruginosa?
A:
Otitis externa (swimmer’s ear)
Ophthalmitis (especially post-trauma; isolation from eye is extremely critical)
Osteomyelitis
Endocarditis
RT infections (Cystic Fibrosis Patients)
50Q: What is a key characteristic of the Stutzeri group regarding pigment?
A:
Does not produce fluorescent pigment
51Q: What colony characteristics does Pseudomonas stutzeri form?
A:
Forms wrinkled/dry colonies
Entire colonies get picked up together
52Q: How does Pseudomonas stutzeri differentiate from the fluorescent group?
A:
ADH (−)
53Q: What is the typical oxidase result for Burkholderia cepacia?
A:
Typically oxidase (+)
7–14% of isolates may be oxidase negative
54Q: What are the key biochemical characteristics of Burkholderia cepacia?
A:
LDC (+)
10% lactose (+) — “attacks” lactose at 10% concentration
Colistin, Polymyxin B – resistant
Yellow pigment
55Q: What type of infections does Burkholderia cepacia cause?
A:
Life-threatening infections (bacteremia, lung infections), especially in patients with cystic fibrosis or chronic granulomatous disease
Can be associated with decline of lung functions in CF patients
May be contraindication for lung transplant
56Q: What other infections can Burkholderia cepacia cause?
A:
Non-fatal infection of blood, urinary tract, respiratory tract
57Q: What agar is used for selection of Burkholderia cepacia and what does it look like?
A:
BCSA agar (for CF cultures) — yellow colonies
58Q: What colony characteristic is seen in Burkholderia pseudomallei?
A:
Wrinkled colonies in old cultures
59Q: What are the key biochemical characteristics of Burkholderia pseudomallei?
A:
Growth at 42°C (+)
NIT (+), gas produced
Glucose oxidation (+)
Colistin (R), Polymyxin B (R)
60Q: What classification is Burkholderia pseudomallei given?
A:
Category B bioterrorism threat
61Q: Where is Burkholderia pseudomallei found geographically?
A:
Found in soil, water, vegetation
Geography: tropical and subtropical regions of Northern Australia and Southeast Asia (Thailand, Vietnam, Laos)
62Q: What disease does Burkholderia pseudomallei cause?
A:
Melioidosis (Whitmore's disease)
63Q: What are the clinical forms of melioidosis?
A:
Acute disease: septicemia with metastatic lesions, 95% mortality if untreated
Subacute disease (most common): TB-like pneumonia with cellulitis
Also known as: “Vietnamese time bomb”
64Q: What should you NOT do if Burkholderia pseudomallei is suspected?
A:
Do not perform full ID on B. pseudomallei
65Q: What precautions should be taken if Burkholderia is suspected?
A:
Perform all work in a Class II BSC with BSL-3 practices
66Q: What growth characteristics may be seen with Burkholderia pseudomallei?
A:
GNR that may be bipolar stained
Poor growth at 24 hours, wrinkled over time
Musty odor
Growth on MAC at 48 hours
No pigment on MH
May have non-violet pigment on BAP
67Q: When are you unable to rule out Burkholderia pseudomallei?
A:
Growth on MAC +
Oxidase +, Indole −
Polymyxin B or Colistin resistant OR growth on B. cepacia selective agars
Non-hemolytic on BAP, no violet pigment
68Q: What should be done with a suspected Burkholderia pseudomallei isolate?
A:
Refer isolate to Public Health
69Q: What is the typical oxidase result for Burkholderia mallei?
A:
75% are oxidase (−)
70Q: What are the key biochemical characteristics of Burkholderia mallei?
A:
MOT (−)
Growth at 42°C (−)
NIT (+), no gas produced
Glucose oxidation (+)
Colistin (R), Polymyxin B (R)
71Q: What classification is Burkholderia mallei given?
A:
Category B bioterrorism threat
72Q: Where is Burkholderia mallei mostly found?
A:
Mostly found in animals: horses, mules, donkeys
73Q: What disease does Burkholderia mallei cause?
A:
Glanders in horses — respiratory infection
74Q: How are human infections with Burkholderia mallei transmitted?
A:
Rare human infections transmitted via abrasion to the skin
75Q: What should NOT be done if Burkholderia mallei is suspected?
A:
Do not perform full ID on B. mallei
76Q: What precautions should be taken if Burkholderia is suspected?
A:
Perform all work in a Class II BSC with BSL-3 practices
77Q: What growth characteristics may be seen with Burkholderia mallei?
A:
GNCB or small rods growing poorly at 24 hrs
Poor or no growth on MAC
No odor
78Q: When are you unable to rule out Burkholderia mallei?
A:
Indole −
Catalase +
Non-hemolytic, non-pigmented, poor/no growth on MAC
Resistant to Polymyxin B or colistin, AMC S, Pen R
No growth at 42°C, no odor
Non-motile
79Q: What should be done with a suspected Burkholderia mallei isolate?
A:
Refer to Public Health
80Q: What are the biochemical characteristics of Stenotrophomonas maltophilia?
A:
Oxidase (−)
LDC (+)
DNase (+)
Maltose oxidation (+)
Pale yellow or lavender green pigment
81Q: What is Stenotrophomonas maltophilia intrinsically resistant to?
A:
Multiple antimicrobial agents
Treatment of choice: Trimethoprim/sulfmethoxazole
82Q: What patient population is commonly colonized by Stenotrophomonas maltophilia?
A:
Frequent colonizer of hospitalized patients
83Q: What infections are associated with Stenotrophomonas maltophilia?
A:
Nosocomial infections including:
Catheter-related infections
Bacteremia
Wounds
Pneumonia
UTI
84Q: What is unique about Shewanella putrefaciens/algae among non-fermenting bacilli (NFB)?
A:
Only NFB that produce H₂S on TSI or KIA
85Q: What are the characteristics of Shewanella algae?
A:
Growth at 42°C (+)
6.5% NaCl (+)
Beta-hemolytic at 48 hr
86Q: Which organisms are oxidase (+), motility (+) with peritrichous flagella?
A:
Bordetella bronchiseptica
Alcaligenes faecalis (odorans)
Achromobacter species
Ochrobactrum anthropi
87Q: What is a key characteristic of Bordetella bronchiseptica?
A:
Rapid urea (+)
88Q: What is characteristic of Alcaligenes faecalis (odorans)?
A:
Fruity odor / green apple smell
89Q: What are the characteristics of Achromobacter species?
A:
Achromobacter xylosoxidans – saccharolytic
Achromobacter denitrificans – asaccharolytic
Intrinsically resistant to aminoglycosides
90Q: What are key points about Ochrobactrum anthropi?
A:
Previously Achromobacter species
Low virulence and low pathogenicity – but can cause osteomyelitis and endocarditis
Can be misidentified as Brucella species
91Q: What are the characteristics of the “Flavobacterium” group?
A:
Most have yellow pigment
Indole +/−
Penicillin resistant
Saccharolytic
92Q: What are the characteristics of Chryseobacterium meningosepticum / Elizabethkingia meningoseptica?
A:
Indole (+)
Pale yellow or non-pigmented
Polymyxin B (or colistin) resistant
Vancomycin sensitive
Penicillin resistant
Growth on MAC (−), though some strains can grow
Meningitis in neonates
93Q: What differentiates the Sphingobacterium and Myroides groups?
A:
Both are indole (−)
Sphingobacterium: esculin (+)
Myroides: esculin (−)
94Q: What are the general characteristics of Moraxella spp. (Group 3: OX (+), MOT (−))?
A:
GS: coccobacilli, diplococci, or diplobacilli
Asaccharolytic
Non-pigmented
Penicillin sensitive
Growth on MAC (variable)
Moraxella nonliquefaciens is the most commonly isolated species
95Q: What is Moraxella lacunata associated with?
A:
Eye infection
Digest Loeffler’s serum slant
96Q: How does Moraxella osloensis differ from Neisseria gonorrhoeae?
M. osloensis:
GNCB
MTM −
BAP +
Growth at 22°C (+)
GLUC (−)
Butyrate (+)
NGC:
GNDC
MTM +
BAP −
Growth at 22°C (−)
GLUC (+)
Butyrate (−)
97Q: What are the Group 3 biochemical characteristics of E. meningoseptica?
A:
Indole (+)
Glucose (+)
Esculin (+)
Gel (+)
Colistin (R)
Oxidase (+)
Motility (−)
98Q: What are the Group 3 biochemical characteristics of Sphingomonas?
A:
Indole (−)
Glucose (+)
Esculin (+)
Gel (−)
Colistin (R)
Oxidase (+)
Motility (−)
99Q: What are the Group 3 biochemical characteristics of Myroides?
A:
Indole (−)
Glucose (−)
Esculin (−)
Gel (+)
Colistin (R)
Oxidase (+)
Motility (−)
100Q: What are the Group 3 biochemical characteristics of Moraxella?
A:
Indole (−)
Glucose (−)
Colistin (S)
Oxidase (+)
Motility (−)
101Q: What are the general characteristics of Acinetobacter spp.
(Group 4: OX (−), MOT (−))?
A:
Gram stain: can be coccobacilli
102Q: What are the characteristics of Acinetobacter baumannii?
A:
Saccharolytic
Non-hemolytic
10% lactose (+)
103Q: What are the characteristics of Acinetobacter lwoffii?
A:
Non-hemolytic
Growth on MAC (variable)
104Q: What is characteristic of Acinetobacter haemolyticus?
A:
Beta-hemolytic
105Q: What resistance issue is associated with hospital strains of Acinetobacter species?
A:
May become resistant to multiple antimicrobial agents
Meropenem-resistant Acinetobacter baumannii
106Q: What patient population is frequently colonized by Acinetobacter species?
A:
Frequent colonizer of hospitalized patients
107Q: What infections are associated with Acinetobacter species?
A:
Nosocomial infections of:
GU tract
Respiratory tract
Wounds
Soft tissues
Blood
108Q: What are the characteristics of Pseudomonas oryzihabitans?
(mot, glucose, yellow pigment, esculin, arginine)
A:
Motility (+)
Glucose (+)
Yellow pigment (+)
Esculin (−)
Arginine: 14% (+)
109Q: What are the characteristics of Pseudomonas luteola?
A:
Motility (+)
Glucose (+)
Yellow pigment (+)
Esculin (+)
Arginine (+)
110Q: What are the characteristics of Asaia species?
A:
Oxidase (−)
Motile
Oxidize glucose
Meropenem resistant
111Q: What are the characteristics of Methylobacterium species?
A:
Dry pink colonies, appear dark under UV light
Gram stain: vacuolated pleomorphic, may resist decolorization
Oxidase (+), motile, MAC (−)
Better growth on SAB
112Q: What are the characteristics of Roseomonas species?
A:
Non-vacuolated, plump and coccoid in pairs and chains
Better growth on SAB
Colonies = mucoid, runny
Can be oxidase (−), acetamide (+), not dark under UV light
113Q: What are the general characteristics of asaccharolytic coccoid NFBs?
A:
Oxidase (+)
Indole (−)
114Q: What is characteristic of Psychrobacter phenylpyruvicus?
A:
Non-motile
115Q: What are Oligella species associated with?
A:
Mostly isolated from UT
Can cause urosepsis
116Q: What are the characteristics of Oligella urethralis?
A:
Non-motile
Urea (−)
Nitrate (−)
117Q: What are the characteristics of Oligella ureolytica?
A:
Motile
PDA (+)
Rapid urea (+)
Nitrate (+)
118Q: Which organisms are known to be misidentified as Brucella species?
A:
Oligella ureolytica
Psychrobacter phenylpyruvicus
119Q: What are the characteristics of Chryseobacterium indologenes?
A:
Oxidase (+)
Indole (+)
Deep yellow pigment
Vancomycin sensitive (unusual for gram negative)
120Q: What is characteristic of Empedobacter brevis?
A:
Pale yellow pigment
121Q: What is characteristic of Delftia acidovorans?
A:
Pumpkin color in OMI when Kovac’s reagent is added
122Q: What are the shared characteristics of the next two organisms (Weeksella and Bergeyella)?
A:
Doesn’t grow on MAC
Non-pigmented
Asaccharolytic
Penicillin sensitive
123Q: What are the characteristics of Weeksella virosa?
A:
Mucoid colonies
Adherent
Tan-brown
Urea (−)
Colistin sensitive
124Q: What are the characteristics of Bergeyella zoohelcum?
A:
Sticky colonies
Tan-yellow
Urea (+)
Colistin resistant
Associated with dog bite wound