Notes on Pseudomonas and Acinetobacter spp.

Flashcards covering important concepts and characteristics of Pseudomonas and Acinetobacter species relevant for clinical bacteriology.

Pseudomonas spp.

Commonly known as pseudomonads, gram(-) bacilli or coccobacilli, strictly aerobic, oxidase(+), motile with polar flagella.

Pseudomonas aeruginosa

Leading cause of nosocomial respiratory infections and UTI; known for its virulence factors like endotoxins and exotoxins.

Pseudomonas mendocina

Considered a contaminant, has nonwrinkled, flat colonies, oxidizes glucose and xylose, oxidase and ADH(+) but does not produce pyoverdin.

Pseudomonas fluorescens

Characterized by production of pyoverdin (+), pyocyanin (-) and can cause infections at low temperatures.

Pseudomonas putida

Has pyoverdin (+) and is distinguished from other fluorescent pseudomonads, nitrate to nitrite reduction (-).

Pseudomonas luteola

Found in rice paddies and hospital drains, oxidase-, catalase (+), oxidizes glucose.

Acinetobacter baumannii

Common cause of nosocomial infections, found in soil and water, oxidase(-), catalase(+), strictly aerobic.

Pseudomonas oryzihabitans

Grows on MAC agar, produces an intracellular yellow pigment, can oxidize glucose.

Pseudomonas pseudoalcaligenes

Notable as a contaminant, oxidase(+), exhibits biochemical negativity in multiple tests.

Oxidase test

A biochemical test to determine if an organism produces cytochrome c oxidase.

MacConkey agar

A selective/differential agar used for isolating gram-negative bacteria and lactose fermenters.

Pseudomonas stutzeri

Forms wrinkled, leathery colonies, can grow anaerobically in nitrate media.

Burkholderia cepacia

Oxidase (+) with weak activity, motile, associated with infections in cystic fibrosis patients.

Burkholderia mallei

Causes glanders, a serious zoonosis primarily affecting horses, classified as a potential bioterrorism agent.

Stenotrophomonas maltophilia

Third most common non-fermentative gram (-) bacilli, associated with various infections.

Alcaligenes faecalis

Characterized by an apple-like odor, oxidase & catalase (+), motile, associated with UTI.

Exotoxin A

A virulence factor of Pseudomonas aeruginosa that blocks protein synthesis, similar to diphtheria toxin.

Pyocyanin

A blue-green pigment produced by Pseudomonas aeruginosa indicating its presence in cultures.

MALDI-TOF

Matrix-assisted laser desorption/ionization time-of-flight, a technique used for identifying microbial species.

Oxidizer

An organism that derives energy through the oxidation of substrates.

Non-oxidizer

Typically refers to organisms that do not oxidize carbohydrates to derive energy.

Infections cause by Pseudomonas aeruginosa

Can lead to conditions such as skin infections, keratitis, and pneumonia.

Colistin

An antibiotic that Acinetobacter baumannii is increasingly susceptible to.

Pleomorphic

Describing an organism that can assume different forms or shapes, often seen in Acinetobacter.

Gram-negative

Refers to bacteria that do not retain the crystal violet stain used in the Gram staining protocol.

Cetrimide agar

Selective medium that enhances pigment production in Pseudomonas aeruginosa.

ADH (arginine dihydrolase) test

A biochemical test to determine the ability of an organism to produce the enzyme arginine dihydrolase.

DNase test

A test used to detect the presence of deoxyribonuclease in bacterial strains.

Endotoxin

A toxic component of the outer membrane of gram-negative bacteria, responsible for severe inflammatory responses.

Fructose utilization

Ability of certain bacteria to metabolize fructose as a carbon source during growth.

Bacillus species

Refers to the genus of rod-shaped, gram-positive bacteria; in this context, contrasting to gram-negative options.

Hydrolysis of gelatin

A test to check an organism's ability to hydrolyze gelatin into amino acids.

Culture media

Nutrient solutions used to grow, isolate, and identify microorganisms in lab settings.

Proteases

Enzymes that break down proteins into smaller polypeptides or amino acids.

Pyoverdins

A type of siderophore produced by Pseudomonas spp. that chelates iron.

Lactose fermentation

The metabolic process where carbohydrates are converted into lactic acid, commonly tested to identify bacterial species.

Septicemia

Presence of bacteria in the blood, often causing severe systemic infections.

Cystic Fibrosis

A genetic disorder that affects the lungs and digestive system, often leading to Pseudomonas aeruginosa infections.

Intrathecal chemotherapy

Administration of chemotherapy drugs into the spinal canal, posing risk for infections.

Ventilator-associated pneumonia

A lung infection that can develop in patients who are on mechanical ventilation.

Ecthyma gangrenosum

Skin infection associated with Pseudomonas aeruginosa, often in immunocompromised patients.

Pilus

A hair-like appendage on bacteria that aids in attachment to surfaces and cells.

Mucoid production

Refers to the production of a gelatinous substance by bacteria, often indicating virulence.

Brown-black pigment

A pigment produced by some bacteria indicating the presence of 2-aminoacetophenone.