Non-Fermentative Gram Neg Bacilli (Glucose oxidizers) Flashcards
What is cellular respiration?
Release of energy that’s stored in chemical bonds of glucose and other carbs. That energy is used to produce ATP.
Why is the EMP pathway used more in anaerobes vs. the ED pathway?
The pathway is greatly utilized because EMP yields more ATP than ED glycolytic pathway. (2 ATP/ glucose)
When is the ED pathway used?
It’s utilized more commonly in aerobic vs. anaerobes. (1 ATP/ glucose). An advantage is that it requires less enzymatic protein to carry out glucose metabolism vs. EMP pathway.
True/ false? Fermentation doesn’t have to occur in the absence of oxygen, it occurs without the need for oxygen
True. (MacConkey agar)
What is the definition of oxidation?
Any process in which the oxygen content of a compound is increased; any reaction in which the positive valence of a compound or a radical is increased because of a loss of electrons. WEAK ACID FORMED, NO GAS PRODUCED.
What does the oxidative- fermentative test determine?
It determines if GRAM NEG BACTERIA metabolize carbs oxidatively, fermentation, or are assacharolytic and therefore have no ability to use carbs in the media.
What is the indicator used in OF media?
Bromthymol blue- color change indicates acidity
Acid in open tube only
Oxidative
No reaction in either
Assacharolytic
Acid in both open/ closed tubes
fermentation or possibly fermentation and oxidation both.
All are glucose ______
Non-fermenters (some are oxidizers or some are assacharolytic).
Media?
SBAP and Chocolate
Most are obligate ____
Aerobes.
Most are oxidase ___
Positive. (except for Acinetobacter and Stenotrophomonas)
Pseudononas aeruginosa: grows well where? Norma flora? Found in what patients typically?
Grows well in moist environments (hot tubs, sinks, showers). RARELY NORMAL FLORA. Found in patients with cystic fibrosis causing respiratory infection (key pathogen).
True/ false? Pseudomonas aeruginosa is the 2nd most commonly isolated glucose non-fermenter clinically.
False. 1st common
ID of Pseudomonas aeruginosa.
Glucose oxidizer. Oxidiase + MAC + (clear) Motile, monotrichous polar flagella Has a spreading, flat appearance on SBAP with serrated edges and green pigment and metallic sheen. GRAPE TO CORN TORTILLA ODOR. Common cause of nosocomial infections.
What are the virulence factors of Pseudomonas aeruginosa?
Exotoxin A- inhibits protein synthesis in host cells
Alginate- surface carb that impedes phagocytosis.
Pyocyanin- blue pigment produces reactive oxygen species causing tissue damage.
Pili-for attachment to host cells
intrinsic resistant to antimicrobials.
What are Pseudomonas pigments?
Pyocyanin- blue/ green (only produced by Pseudomonas aeruginosa)
Pyoveridin- yellow, visualize UV light
Pyorubin- rust
Pyomelanin- brown (helps microbes survive oxidative stress)
Psudomonas aeruginosa: incubation? oxidase? TSI?
Incubates well at 42 degrees C
Oxidase positive
TSI: Slant no change, alkaline butt (K/K), gas neg, H2S neg. *
What is Pseudomonas aeruginosa resistant and susceptible to?
Resistant: penicillin and ampicillin
Susceptible: aminoglycosides, extended spectrum pencillins, carbapenems, quinolones
What microbes are most common cause of lung infection in CF patients in the 1st decade?
Staphlococcus aureus and Haemophilus influenzae
Pseudomonas aeruginosa is most common in the 2nd and 3rd decades.
Is Burkholderia cepacia normal flora? Where is it found?
Not normal flora! Found in soil, water, plants, found in patients with CF.
How is Burkholderia cepacia spread?
Where can it be found?
Kissing and doorknobs (person to person)
Able to survive on or in medical devices and disinfectants
ID of Burkholderia cepacia?
Grows on SBAP, Chocolate, MAC.
MOTILE
Oxidase pos
LDC pos
What is Burkholderia cepacia resistant to?
Polymyxin B
resistant to many antibiotics. treatment is problematic in CF patients.
What score of the Bartletts screening can be worked up? Rejected?
1 or above work up
0 or less rejected
Burkholderia mallei: normal flora? Causes what?
Not normal flora!
Causes glanders in horses, mules, etc.
Rarely infects humans
ID of Burkholderia mallei
Grows well on SBAP, Chocolate
MAC +
Oxidase +
How would humans contract glanders?
Via cuts/abrasions and contact with horse tissues/ fluids (very rare)
no human to human transmission
if in blood can be fatal
Symptoms of glanders?
Fever, headache, muscle aches, chills
What is the treatment of glanders?
Tetracyclines
Burkholderia pseudomallei: normal flora? Found where?
Not normal flora!
Found in soil, rice paddies (surface water)
ID of Burkholderia pseudomallei
Transmitted via inhalation or inoculation through cuts.
MAC +
Oxidase +
Causative agent of Melioidosis
Describe Melioidosis.
AKA Whitmore’s disease
Primarily in SE Asia
Localized: fever, ulceration, abscess
Pulmonary: cough, chest pain, fever, headache
Blood stream: fever, headache, respiratory distress, joint pain
Disseminated: fever, weight loss, headache, seizures
What can be the treatment for Melioidosis?
Oral (doxycycline) or intravenous (ceftazidime)
Acinetobacter spp: normal flora?
Possibly of skin and respiratory in hospitalized patients (prolonged stays)
True/ false? Acinetobacter is the most common glucose non-fermenter isolated clinically.
False. 2nd most common
ID of Acinetobacter spp?
Grows well on SBAP, Chocolate, MAC (variable)
Oxidase -
Catalase +
Non-motile
Doesn’t reduce nitrates (NO3) to nitrites (NO2)
Pseudomonas aeruginosa does
Can create a purple hue on MAC though they’re NOT lactose fermenters.
Gram stain: plump gnr often in pairs.
What can Acinetobacter cause?
Respiratory infections, UTI’s, wound and blood infections.
Stenotrophomonas maltophilla: normal flora?
Possibly of respiratory tract of hospital patients (prolonged stays)
True/ false? Stenotrophomonas maltophilla is the 3rd most common glucose non-fermenter isolated clinically.
True.
ID of Stenotrophomonas maltophilla?
Strong maltose oxidizer Glucose oxidizer *oxidase -* MAC + SBAP shows yellow to lavendar pigment Motile with a tuft of flagella Ammonia smell Arg - Ornithine - Lys + Dnase + Polymyxin B sensitive
