Microbiology SOLO 5

Microbiology SOLO 5 exam notes

O-F media purpose

test used to differentiate organisms based on the ability to produce acid byproducts from carbohydrate substrates

The production of an acid in an open tube will result in a color change from red to yellow and indicates…

an oxidizer

The production of an acid in a closed tube will result in a color change from red to yellow and indicates…

a fermenter

Burkholderia cepacia may colonize respiratory tract of patients with?

cystic fibrosis

Burkholderia cepacia has intrinsic resistance to…

multiple antibiotics

Which agar are used to isolate Burkholderia cepacia

• Pseudomonas cepacia agar

• Burkholderia cepacia selective agar

Identification of Burkholderia cepacia

• dirt-like odor

• polar flagella

• lysine decarboxylase positive

• arginine dihydrolase negative

Burkholderia mallei is associated with?

• associated with close animal contact

• cause of glanders in horses, donkeys, mules

Identification of Burkholderia mallei

• non-motile/atrichous

• lysine decarboxylase negative

• nitrate reductase positive

• gelatinase negative

Burkholderia pseudomallei

• southeast Asia

• causes melioidosis

• bioterrorism agent

Identification of Burkholderia pseudomallei

• ashdown media (violet purple colonies)

• polar flagella

• lysine decarboxylase negative

• nitrate reduction positive

• fluorescence negative

Pseuodomonas aeruginosa

• hot tubs, whirlpools, and contact lens solutions (aquatic)

• “swimmer’s ear” (otitis externa)

• respiratory infections in CF patients

pyocyanin

blue pigment tht contributes tot he characteristic green color and damages cells by producing reaactive oxygen species

Identification of Pseudomonas aeruginosa

• spreading and flat with serrated/feathered edge

• produces pyocyanin and pyoverdin

• polar flagella

• grape like or corn tortilla odor

• growth at 42C

• gelatinase positive

• fluorescence positive

Pseudomonas fluorescens, putida, and stutzeri

• soil and water habitat

• significance should always be questioned

Pseudomonas fluorescens identification

• polar flagella

• gelatinase positive

• does not grow at 42C

identification of Pseudomonas putida

• polar flagella

• gelatinase negative

• does not grow at 42C

identification of Pseudomonas stutzeri

• dry and wrinkly colonies

• polar flagella

• gelatinase positive

• growth at 42C

Antimicrobial therapy and Burkholderia cepacia

rarely eradicates the organism

Pseudomonas aeruginosa common antimicrobial therapy

piperacillin/tazobactam

Shewanella putrefaciens

• aquatic/marine

• often in mixed cultures

identification of Shewanella putrefaciens

• Lavender greening of blood agar

• polar flagella

• glucose oxidation negative

• H2S positive

Flavobacterium/ Chryseobacterum, Myroides, Sphingeobacterium and Elizabethkingia general characteristics

• most are yellow pigmented, oxidase positive, and glucose oxidizers

• main species is Elizabethkingia meningoseptica

Elizabethkingia meningoseptica

• nosocomial

• may be transmitted from birth canal to neonate

• meningitis most notable infection

identification of Elizabethkingia meningoseptica

• non-motile/atrichous

• indole positive

• gelatinase positive

identification of Myroides sp.

• yellow pigmented colonies on BAP

• fruity odor

• non-motil/atrichous

• indole negative

• gelatinase positive

Identification of Sphingobacterium

• non-motile/atrichous

• gelatinase negative

• nitrate reduction negative

Achromobacter denitrificans

• environmental

• compromised patients and contaminated fluids/medical solutions

• inherent resistance to disinfectants and antimicrobial agents

Identification of Achromobacter denitrificans

• peritrichous flagella

• nitrate reduction positive

• dose not oxidize xylose

• urea negative

Achromobacter xylosoxidans

• moist areas of a hospital

• compromised patients exposure to contaminated fluids, soaps, disinfectants

• inherent resistance to disinfectants and antimicrobial agents

Identification of Achromobacter xylosoxidans

• peritrichous flagella

• nitrate reduction positive

• gas from nitrate positive

• oxidizes xylose

Alcaligenes faecalis

• may colonize skin, moist hospital environment or soil/water

• compromised patients exposure to contaminated medical devices and solutions

• often a contminant

Identification of Alcaligenes faecalies

• fruity odor

• peritrichous flagella

• urea negative

• nitrate reduction negative

Bordetella bronchiseptica

• not part of normal human microbiota

• normal respiratory flora for DOGS

• exposure to contaminated respiratory droplets during close contact with animals

• opportunistic infection in compromised patients with a history of close animal contact

Identification of Bordetella bronchiseptica

• peritrichous flagella

• urea positive

Identification of Comamonas testosteroni

• polar flagella

• does not oxidize fructose or glucose

• insoluble pigment negative

Pseudomonas alcaligenes and Pseudomonas pseudoalacaligenes

• recovered from respiratory secretions of patients with cystic fibrosis

Identification of Pseudomonas alcaligenes

• polar flagella

• does not oxidize glucose, fructose, or mannitol

• insoluble pigment positive (>90% strains)

• urea negative

Identification of Pseudomonas pseudoalcaligenes

• polar flagella

• does not oxidize glucose or manntol

• oxidizes fructose

Identification of Rosemonas sp.

• pink pigmented

• polar flagella

• does not oxidize fructose

• urea positive

General characteristics for Aeromonas sp.

• oxidase positive

• glucose fermenting

• produce acid from oxidative and fermentative metabolism

Aeromona sp. epidemiology

• aquatic environments around the world

• traumatic inoculation of fish fins or fishing hooks

• can cause gastroenteritis espcially in children

Identification of Aeromonas caviae complex

• bi-polar flagella

• oxidase positive (diff. from Yersinia)

• non hemolytic on BAP

• string test negative

• ferments maltose

Identification of Aeromonas hydrophila complex

• bi-polar flagella

• beta hemolytic

• string test negative

• ferments maltose and mannitol

Chromobacterium violaceum

• from soil or water of tropical and subtropical regions

• begins with cellulitis and can rapidly progress to systemic infections with abscess formation in various organs and septic shock

Identification of Chromobacterium violaceum

• bi-polar flagella

• black or very dark purple colonies

• smells like ammonium cyanide (almonds)

• string test negative

• does not ferment maltose or mannitol

general characteristics for Vibrio sp.

• oxidase positive

• most require sodium for growth

epidemiology of Vibrio sp.

• contaminated shellfish or other seafood

• brackish or saltwater

Vibrio cholerae disease

• causes cholera

• Cholera toxin (CT) and several others

• fluid loss causes dehydration and hypotension

• “rice water” stools

Identification of Vibrio sp.

• show characteristic rapid darting ro “Shooting star” motility

• all string test positive

• TCBS media of choice

  • inhibit GP with bile salts and inhibit other intestinal orgs with high pH

  • green/yellow depending on whther they ferment sucrose

Identificaiton of Vibrio cholerae

• growth in 6% and 0% NaCl

• yellow growth on TCBS

identification of Vibrio alginolyticus

• growth in 6% but NONE in 0% NaCl

• yellow growth on TCBS

Vibrio parahaemolyticus

• Growth in 6% but NONE in 0% NaCl

• green growth on TCBS

String test

• used to differentiated Vibrio and Aeromonas species

• organisms emulsified in 0.5% sodium deoxycholate, which lyses Vibrio but not Aeromonas

• cell lyses releases DNA which can be pulled into a string with an inoculating loop

Vibrio cholerae antimicrobial testing

• rehydration with antibiotics is main therapeutic action

• known resistance to tetracyclin, chloramphenicol, trimeth/sulfa

Aeromonas species antimicrobial testing

• gastroenteritis cases may not need them

• soft tissue and septicemia may use ceftriaxone

• capable of producing beta lactamases