Week 1: Nonfermenting GNR

fermentation of sugars: environment and byproducts

1. anaerobic

2. high amount of acids

oxidation of sugars: environment and byproducts

1. aerobic

2. low amount of acids

embden-meyerhof-parnas pathway

glycolysis

entner-doudoroff pathway

aerobic

asaccharolytic

no sugar catabolization and no acid production

TSI result of nonfermenters

K/NC

oxidation can product weak acids, but are not detected with ________

TSI

are all nonfermenters oxidase +?

no

Enterobacteriaceae oxidase reaction

negative, except Plesiomonas

nonfermenter growth on MAC

poor

OF test: oxidative result

1. O tube — acid on top

2. F tube — no change

OF test: asaccharolytic tube

1. O tube — alkaline on top

2. F tube — no change

pH indicator for OF test

bromothymol blue

hugh-leifson broth contents

carbohydrates are more abundant than proteins

clinically significant Pseudomonas spp.

1. P. aeruginosa

2. P. stutzeri

3. P. fluorescens

4. P. putida

clinically significant Burkholderia spp.

1. B. cepacia

2. B. pseudomallei

3. B. mallei

clinically significant Stenotrophomonas spp.

S. maltophilia

clinically significant Alcaligenes spp.

A. faecalis

clinically significant Brevundimonas spp.

B. diminuta

Pseudomonads genera

1. Pseudomonas

2. Burkholderia

3. Stenotrophomonas

4. Alcaligenes

5. Brevundimonas

Pseudomonas aeruginosa cell morphology

1. long thin GNR

2. may be encapsulated

3. single polar flagellum

are nonfermenting GNR aerobic or anaerobic?

aerobic

when can P. aeruginosa grow without oxygen?

if nitrate is available as a respiratory electron acceptor

P. aeruginosa appearance on BAP

1. often beta hemolytic

2. ground glass, jagged edges

3. aluminum foil sheen

4. blue-green, or red-brown pigment diffusion

5. may be mucoid

P. aeruginosa odor

grape or corn taco shell

alginate slime

1. P. aeruginosa

2. associated with CF patients

rapid ID criteria for P. aeruginosa

1. NLF on MAC

2. oxidase +

3. blue-green pigment

4. grape odor

P. aeruginosa sugar oxidation reactions

1. glucose +

2. fructose +

3. xylose +

key biochemical reactions for P. aeruginosa (besides sugars)

1. acetamide deaminase +

2. 42C growth

3. nitrate reductase +

4. motility +

5. Arg decarboxylase +

Pseudomonas aeruginosa usually requires what for an infection to begin?

break in the body’s defenses

populations at risk for Pseudomonas aeruginosa infections

1. chronic lung disease

2. immunosuppressed

3. ICU patients

4. CF patients

5. severe burns

P. aeruginosa can cause chronic ____________ in CF patients

pneumonia

P. aeruginosa “swimmer’s ear”

wet environment of the external auditory canal mimics the natural environment of the bacteria

common conditions caused by P. aeruginosa

1. respiratory infections

2. CF colonizer

3. bacteremia and septicemia

4. swimmer’s ear

5. bacterial keratitis

6. chronic osteomyelitis

7. UTIs

8. NEC in infants

9. skin and soft tissue infections

virulence factors of P. aeruginosa

1. alginate

2. pilli

3. neuraminidase

4. LPS

5. exotoxin A

6. enterotoxin

7. exoenzyme S

8. phospholipase C

9. elastase

10. leukocidin

11. pyocyanin

P. aeruginosa treatment

1. antipseudomonal beta lactam agent paired with an aminoglycoside

2. CF patients need aerosolized aminoglycoside

fluorescent Pseudomonas spp.

1. P. fluorescens

2. P. putida

Pseudomonads are mostly oxidase and catalase __________

positive

nonfermenting GNRs are typically _______________ organisms

environmental

how can P. fluorescens and P. putida be differentiated from P. aeruginosa?

1. no growth at 42C

2. acetamide deaminase -

how can P. fluorescens be differentiated from P. putida?

P. fluorescens grows at 4C and hydrolyzes gelatin

conditions associated with P. fluorescens and P. putida

1. abscesses

2. UTIs

3. septicemia

4. septic arthritis

5. nosocomial infections in immunosuppressed

P. fluorescens and P. putida are generally not clinically ___________

significant

______________ is associated with pseudo-bacteremia due to contamination of disinfectant solutions

P. fluorescens

pigment production by P. aeruginosa

1. pyorubin

2. pyocyanin

3. pyoverdin

pigment production by P. fluorescens and P. putida

pyoverdin

which Pseudomonas sp. is nonfluorescent?

P. stutzeri

P. stutzeri appearance on BAP

1. wrinkled, leathery, hard

2. yellow or brown pigment

Pseudomonads genera motility

motile

is P. stutzeri a denitrifier?

yes

how can P. stutzeri be differentiated from P. aeruginosa and most common Pseudomonads?

Arg decarboxylase negative

P. stutzeri sugar oxidation

maltose

conditions associated with P. stutzeri

1. bacteremia

2. bone infection

3. endocarditis

4. eye infections

5. meningitis

6. skin infections

7. UTIs

Burkholderia cepacia appearance on BAP

1. slight yellow or green pigment

2. smooth and slightly raised

Burkholderia cepacia appearance on MAC

light pink after 4-7 days

Burkholderia cepacia is known as a _________ pathogen

plant

Burkholderia cepacia odor

dirt

B. cepacia is associated with ________ patients

CF

BCSA

1. B. cepacia selective agar

2. colonies vary in size, with pink to yellow zones

OFPBL agar

1. oxidative fermentative polymyxin B bacitracin lactose

2. B. cepacia has yellow colonies

B. cepacia sugar oxidation

1. glucose +

2. maltose +

3. lactose +

4. mannitol +

B. cepacia is DNase __________

negative

B. cepacia is lysine decarboxylase __________

positive

Burkholderia cepacia virulence factors

1. LPS

2. can adhere to mucin

3. MDR

CF patients with P. aeruginosa later may develop colonization with _____________

B. cepacia

once colonization with B. cepacia, CF patients are no longer eligible for what?

lung transplant

B. cepacia antibiotic resistance

resistant to aminoglycosides, which is unsual for nonfermenters

B. cepacia antibiotic treatments

1. minocycline

2. meropenem

3. ceftazidime

4. fluoroquinolones

5. chloramphenicol

6. trimethoprim-sulfamethoxazole

species considered to be bioterror agents

1. Burkholderia pseudomallei

2. Burkholderia mallei

which species is found in the tropics and subtropics?

Burkholderia pseudomallei

conditions associated with B. pseudomallei

1. severe pulmonary infections

2. melioidosis

B. pseudomallei appearance on BAP

1. smooth and mucoid

2. or dry and wrinkled

B. pseudomallei appearance on MAC

pink after 4 to 7 days

B. pseudomallei odor

musty or earthy

how can B. pseudomallei be differentiated from P. stutzeri

1. lactose +

2. lysine decarboxylase +

how can B. pseudomallei be differentiated from Pseudomonas spp. and S. maltophilia?

resistant to colistin and polymyxin B

how can B. pseudomallei be differentiated from B. cepacia and B. gladioli?

arginine decarboxylase +

colloquial name for melioidosis

vietnamese time bomb

Burkholderia mallei is associated with infections in ___________

animals

what is the etiologic agent of glanders?

B. mallei

Acinetobacter cell morphology

GN coccobacilli in singles, pairs, and short chains

Acinetobacter baumannii can be confused with…

Neisseria or Moraxella

Acinetobacter baumannii appearance on BAP

1. smooth

2. opaque

3. raised

4. wet looking

5. gray-white

Acinetobacter baumannii appearance on MAC

NLF with slight bluish-pink tint

nonmotile species

1. Acinetobacter baumannii

2. Elizabethkingia meningoseptica

3. Moraxella

oxidase negative species

1. Acinetobacter baumannii

2. Stenotrophomonas maltophilia

what is a difference between A. baumannii and A. lwoffi?

1. A. baumannii is glucose-oxidizing

2. A. lwoffi is asaccharolytic

what are most beta-hemolytic species of Acinetobacter called?

A. haemolyticus

how can A. baumannii be differentiated from S. maltophilia?

gelatin and lysine decarboxylase -

colloquial names for Acinetobacter

1. iraqibacter

2. gram negative MRSA

conditions associated with Acinetobacter baumannii

1. severe pneumonia

2. bacteremia

3. UTIs

4. burn patients

Acinetobacter treatment

1. specialized to individual isolate

2. colistin

3. carbapenems

4. 3rd gen cephalosporins and quinolones

colistin

1. nephrotoxic and neurotoxic

2. few antibiotics that can treat MDR strains

Stenotrophomonas maltophilia appearance on BAP

1. nonhemolytic

2. large, smooth, shiny

3. gray-white or slight yellow

4. can have lavender-green discoloration of agar

Stenotrophomonas maltophilia odor

ammonia

Stenotrophomonas maltophilia appearance on MAC

NLF, may have brown discoloration

S. maltophilia sugar oxidation

1. maltose +

2. glucose +

how can Stenotrophomonas maltophilia be differentiated from Acinetobacter?

motile and lysine decarboxylase +

how can S. maltophilia be differentiated from B. cepacia?

DNase +

how can S. maltophilia be differentiated from B. cepacia with antibiotics?

colistin and polymyxin B susceptible