Bacteriologic Culture Media

Routine Primary Plating Media:

1) Nonselective (ex. SBA)
2) Enriched for ___ organisms (ex. CHOC)
3) Selective and differential for ___ gram neg bacilli (ex. MAC)
4) Selective media for gram ___ organisms (ex. CNA)
5) Broth to ___ media (help grow things that are in low numbers)

fastidious; enteric; pos; supplement

Sheep Blood Agar (SBA) is used in ___ culture basically as it cultivates a ___ variety of bacterial organisms.

It is a ___ soy agar base with ___ to 10% sheep blood.

It’s nonselective purpose is to enrich the growth of bacterial organisms. It’s differential purpose is to detect and characterize ___ activity.

every; wide

Tryptic; 5

hemolytic

On SBA, alpha hemolysis is the ___ lysis to RBCs - resulting in the ___ discoloration.

Beta hemolysis is characterized by the ___ RBC destruction - resulting in the ___ appearance.

Gamma hemolysis is ___-hemolytic, no changes are apparent.

partial; green; complete; transparent; non

Chocolate agar is an ___ agar for the growth of ___ organisms (H. influenaze & Neisseria spp.).

The plate is pre-___ meaning that blood nutrients are readily accessible for organisms. It contains cell-free ___ that releases hemin (___ factor) and has Nicotinamide Adenine Dinucleotide (NAD) (___ Factor).

enrichment; fastidious

lysed; hemoglobin; X; V

There is an abundance of Nicotinamide Adenine Dinucleotide (NAD) in RBCs; however, some fastidious organisms ___ make it on their own - so they get it from the RBCs on ___ agar.

cannot; chocolate

The ___ and ___ factor are crucial in chocolate agar, allowing fastidious organisms to grow.

X; V

MacConkey agar is almost ___ used just like SBA. It is selective for gram ___ rods, ____ specifically that are found in the gut.

It is a selective and ___ medium. It is differential for the utilization of the carbohydrate ___, detecting bacteria that lactose ___.

The bile ___ and crystal violet inhibit gram pos organisms.

always; neg; enterics

differential; lactose; ferment

salts

On MAC, lactose fermenters grow as ___ to red colonies. Non-lactose fermenters are clear, colorless.

pink

Columbia CNA agar is a ___ and differential (for hemolysis) medium. It selects for the growth of gram ___ microorganisms.

It is made of a Columbia agar base enriched with ___% sheep blood. It also contains ___ and ___ acid that are antimicrobial components effective at inhibiting gram neg organisms.

selective; pos

5; Colistin; Nalidixic

P. mirabilis is typically a contaminant capable of "___ motility" that can cover up any pathogen underneath it. To inhibit this growth, ___ is used because this bacteria is a gram neg rod.

swarming; CNA

Thioglycolate (Thio) broth is an ___ purpose medium (most stuff is gonna grow on it). It is useful for detecting organisms present in ___ numbers (reducing medium)! Thus, used in ___ with culture plates.

___ requirements of organisms can also be determined through this medium.

all; low; conjunction; oxygen

Name the following oxygen requirements in the Thio broth

a) aerobes
b) anaerobes
c) Facultative
d) Aerotolerant

Mueller-Hinton agar is used for antimicrobial ___ testing. It supports the growth of ___ microorganisms.

Agar itself is not very enriched, can add blood to support growth of some fastidious organisms.

Prepared by streaking organism on plate and then ___ antibiotic discs in plate. Zones of "inhibition" are measured for ___ - the biggest one indicates that the organism IS susceptible to that drug.

susceptibility; most; dropping; width

Anaerobic cultures must be processed ___ and put into an anaerobic environment to recover organisms effectively.

Gas packs, anaerobic chambers/boxes, and anaerobic jars can all be used to ___ oxygen.

quickly; remove

Bacteroides Bile Esculin agar (BBE) is an ___ culture media. Primarily used to isolate members of the ___ fragilis group —- turns agar ___ due to esculin ___ (differential).

Almost ___ else will grow on this.

anaerobic; Bacteroides; black; hydrolysis; nothing

___ is the primary pathogen expected to be seen in gut wound infections.

Bacteroides

Kanamycin-Vancomycin-laked blood agar (KVLB) is selective for gram ___ and differential. It is a medium for ___ cultures.

It is made out of antibiotics (Kanamycin-Vancomycin) which prevent the growth of most ___ anaerobes and gram pos organisms.

neg; anaerobic; facultative

Kanamycin-Vancomycin-laked blood agar (KVLB) is useful in the rapid isolation and presumptive ID of ___ sp. - creating the ___/black pigment production (differential).

Prevotella; brown

The more special the media is the more ___. Specialty media is dependent on specimen ___ and suspective ___ agent.

It is typically ___ and ___ types of medium. Characterized by more ___ formulation or ___ concentrations of common ingredients.

Media choices ___ by laboratory (some places might have different media tailored to their patient population vs ours).

expensive; type; causative

selective; differential; complex; higher

vary

CHROMagars are used to ___ identify isolates based on colony color for the ID of ___, S. ___, and E. ___.

visually; yeasts; aureus; coli

CHROMagars for Methicilin-Resistant S. auerus (MRSA) include the MRSA screening agar that turns ___ after detection and the ___ blue agar that turns blue.

These agars give a ___ ID of S. aureus and requires further testing for ___ ID.

These agars are used for pre-surgery ___ to treat any normal flora MRSA and get rid of it before surgery to prevent any ___ infection.

pink; Denim; presumptive; definitive; screening; accidental

Selective media for ___ pathogens in stool culture include: Campylobacter blood agar, SS agar or Hektoen Enteric agar, and MacConkey Sorbitol agar:

enteric

Sabouraud Dextrose agar is called the work horse for ___ workup. Used for the identification of fungi/___, especially dermatophytes involved with ___ infection.

___ media deters bacterial growth. ID of fungi is aided by appearance of the top and reverse appearance/___.

fungal; yeats; cutaneous

acidic; color

List expected medium growth for Respiratory cultures:
1)
2)
3)

4)

Where ___ gram pos and neg grows!

Blood, Choc, CNA, and MAC

both

Everything that grows on SBA should grow on ___ as well (choc isnt selective); however, not ___ that grows on CHOC will grow on SBA.

Choc; everything

A urine culture that has growth on a SBA (grows everything) but no growth on MAC (selective for gram neg) - we expect the bacterium to be gram ___.

pos

Identification of bacteria is done by:

-Gram stain
-___ (bench tests) - catalase, PYR, indole, oxidase
-Manual (API)

-Automated systems (Vitek and MicroScan)

-MALDI-TOF

-Molecular methods (like PCR - very sensitive to ___)

Rapid; contamination