P1 | Bacterial Morphology (LECTURE) Flashcards by Aleira Marie Francisco

Bacterial Morphology

___ to __ μm in width and __ to __ μm in length

(___-__ um - Mahon)

0.25 to 1 μm in width and 1 to 3 μm in length

(0.4-2 um - Mahon)

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The staining procedure separates almost all medically relevant bacteria into two general types:

Gram Positive
Gram Negative

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Common bacterial cellular morphologies:

(C.C.B.F.C.S)

Cocci (circular)
Coccobacilli (ovoid)
bacillus (rod shaped)
fusiform (pointed end)
curved
spiral shapes

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Microscopic Shapes

found in ocean sediment
has a diameter of 0.1 to 0.3 mm.

Thiomargarita namibiensis

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Microscopic Morphology of Bacteria

(COCCI)

(C.C.P.T)

In clusters
In chains
In pairs
In tetrads

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Microscopic Morphology of Bacteria

(BACILLI)

(C.B.F.P)

Coccobacilli
Bacilli of various sizes (pleomorphism/pleomorphic bacteria)
Fusiform bacilli
Palisading (parallel)

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Microscopic Morphology of Bacteria

(SPIROCHETES)

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round or spherical shaped bacteria.
The resulting arrangement of cocci depends on the PLANE of DIVISION

Cocci (Coccus)

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(DIPLOCOCCUS OR DIPLOCOCCI)

All diplococci appears to be two cocci adjacent to each other except:

Neisseria spp.
(Except: Neisseria weaveri and Neisseria elongata)

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kidney or coffee bean shaped diplococci

Neisseria spp.
- (Except: Neisseria weaveri and Neisseria elongata)

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Is Neisseria spp.
- (Except: Neisseria weaveri and Neisseria elongata) gram positive bacilli or gram negative bacilli?

Gram Negative Bacilli

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flame/lancet shaped diplococci

(SP)

Streptococcus pneumoniae

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Is Streptococcus pneumoniae a gram positive or gram negative?

Gram positive

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What is the plane of division for “DIPLOCOCCUS/DIPLOCOCCI”?

Coccus is divided one (1) plane of division

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COCCI IN CHAINS

Plane of division?

e.g Streptococcus spp.

Coccus is divided by one (1) plane of division but continuously dividing it.

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Coccus in packets of four (4)?

Tetrad/s

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What is the plane of division for “TETRAD/S”?

Coccus is divided two (2) planes of division.

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Example of a Tetrad?

Micrococcus tetragena

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Coccus in cubical packets of eight (8)?

Sarcina/e

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What is the plane of division for “SARCINA/E”?

Coccus is divided three (3) planes of division in a regular pattern

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Example of a Sarcina/e?

(M.L)

Micrococcus luteus

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COCCI IN CLUSTERS

Plane of division?

e.g Staphylococcus aureus

Coccus is divided two (2) planes of division in a irregular pattern; grape-like clusters

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rod shaped, cylindrical, or elongated bacteria

BACILLUS (BACILLI)

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BACILLI MORPHOLOGY

rod shaped bacillus

Single Bacillus

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**BACILLI MORPHOLOGY** bacillus in pair

Diplobacillus

**BACILLI MORPHOLOGY** bacillus in chains

Streptobacillus

**BACILLI MORPHOLOGY** bacillus that are small, short, stout/plump ## Footnote (CB)

Coccobacillus

**BACILLI MORPHOLOGY** Small and short bacillus arranged in school of fish, rail road track, or fingerprint pattern in stained smear ## Footnote (H.D)

Haemophilus ducreyi

Causative agent of Soft changre/chancroid (STI) ## Footnote (HD)

Haemophilus ducreyi

Large, square cut-ends, spore forming bacillus - Arranged in chains ## Footnote (BA)

Bacillus anthracis

causative agent of anthrax

Bacillus anthracis

Large, rounded ends, non-spore forming bacillus - Arranged in chains ## Footnote (FB.SPP)

Fusobacterium spp.

anaerobic bacteria which chiefly found as a normal flora in the gastrointestinal tract (GIT) ## Footnote (FB.SPP)

Fusobacterium spp.

Slim, slender, threadlike bacillus - Sometimes arranged in serpentine cord (crawling snake) pattern in stained smears

Mycobacterium tuberculosis

causative agent of human tuberculosis

Mycobacterium tuberculosis

Examples of branching or filamentous bacilli (A.N.A)

- Actinomyces spp. - Nocardia spp. - Actinomycetes spp.

Club shaped or barb shaped arranged in palisade, fence stick, cigarette packet. - Irregular bacilli - Sometimes resembles X, V, Y, Z, or Chinese character (C.D)

Corynebacterium diphtheriae

causative agent of diphtheria ## Footnote (CB.D)

Corynebacterium diphtheriae

Example of curved or comma shaped bacilli

Vibrio spp.

Sometimes resembles seagull wing - S or C shaped bacilli (C.H.A)

- Campylobacter spp. - Helicobacter spp. - Arcobacter spp.

helical or twisted bacteria

Spirals

_____ which is helical but rigid while the _______ which are helical as well but more flexible in movement

- Spirillum spp. - Spirochetes

Spiral with two or more curves - Quite rigid (S.M)

Spirillum minor/minus

causative agent of sodoku (a rat bite fever infection) ## Footnote (S.M)

Spirillum minor/minus

Loosely twisted spiral - Resembling a stretched spiral (B. spp)

Borrelia spp.

causative agent of relapsing fever and lyme disease ## Footnote (B.SPP)

Borrelia spp.

Tightly twisted spiral - resembling a cork screw (T.P)

Treponema pallidum

causative agent of venereal syphilis

Treponema pallidum

Tightly twisted spiral with one or both ends bent into a hook - Sometimes even resembling an interrogative symbol (L.I)

Leptospira interrogans

causative agent of zoonic infection leptospirosis ## Footnote (L.I)

Leptospira interrogans

imparts an artificial coloration

Staining

The four categories of staining: (D.D.S.I)

1. Direct/simple stain 2. Differential Stain 3. Selective/special stain 4. Indirect/Negative/Relief Stain

usually contains one specific active chromogen in the stain which enhances the appreciation of bacterial size, shape, and arrangement.

DIRECT/SIMPLE STAIN

The commonly used simple stains are: (C.G.M.M)

- Crystal Violet - Gentian Violet - Methylene Blue - Malachite Green

- contains two or more chromogens - This staining technique also includes a decolorization step which is the most critical step in the process.

DIFFERENTIAL STAIN

differentiates gram positive bacteria which stain PURPLE or VIOLET from gram negative which stains RED or PINK.

Gram Stain

What is the color of the stain for gram positive?

Purple or Violet (if the peptidoglycan is thick)

What is the color of the stain for gram negative?

Red or Pink (if the peptidoglycan is thin)

differentiate acid fast organism such as Mycobaterium tuberculosis (A.F.S)

Acid Fast Stain

Mycobaterium tuberculosis stains what color from non-acid fast organisms?

RED

Mycobaterium tuberculosis stains what color from non-acid fast organisms depending on the counterstain?

BLUE OR GREEN

What are the two different staining methods?

1. Ziehl-Neelsen Staining method 2. Kinyoun Staining method

uses fluorescent dyes such as AURAMINE or RHODAMINE or combination of both. - These dyes remain in the cell wall of acid-fast organism even after decolorization

Fluorochrome Stain

Other Stains for Acid Fast Organisms: (P & B)

1. Pappenheim stain 2. Baumgarten stain

PAPPENHEIM STAIN: (color) - Mycobacterium tuberculosis: - Mycobacterium lacticola (smegmatis):

- RED - BLUE

uses ROSOLIC ACID as a decolorizer (B.S)

Baumgarten Stain

BAUMGARTEN STAIN: (color) - Mycobacterium tuberculosis: - Mycobacterium leprae:

- BLUE - RED

stains that specifically highlight or emphasize certain bacterial cell structures or components which aids in the presumptive identification of the bacteria

SELECTIVE/SPECIAL

STAIN FOR CELL WALL (VICTORIA BLUE DYE)

cell wall stains BLUE

STAINS FOR CAPSULE - HISS - TYLER - MUIR - GIN - WADSWORTH - WELCH ## Footnote (PB, LV, LB, - , P&B, PV)

- Pale brown - Light violet - Light blue - capsule is unstained, bacteria will be stained with its margin delineated by the ink - Capsule: pinkish, Bacteria: Blue - Pale violet

Stains for Metachromatic Granules/Babes Ernst Bodies/Volutin - Loeffler’s Alkaline Methylene Blue (LAMB) - Albert - Neisser - Lindegran - Burke’s Technique - Ljubinsky ## Footnote (R,BB,DB,RB,'', DV)

- red - blue black - dark blue - reddish brown - a modified gram's staining technique - dark violet

Stains for Bacterial Spores/Endospores - Fulton-Schaeffer - Dorner - Wirtz-conklin ## Footnote (G,R,G)

- Green - Red - Green

Stains for Flagella ## Footnote (L,G,S,F-C)

- Leifson - Gray - Silver - Fisher-Conn

important component in flagellar stain which coats, swells, precipitates the flagella enhancing its visualization ## Footnote (T.A)

TANNIC ACID

Stains for Rickettsia - CASTAÑEDA - MACHIAVELO - GIEMSA ## Footnote (B,R,B)

- blue - red - blue

Stains for Chlamydia - GIMENEZ - MACHIAVELO - GIEMSA ## Footnote (R,R,P)

- red - red - purple

Stains for Spirochetes - Fontana-Tribondeau - Levaditi Silver Impregnation - India Ink Negative Stain ## Footnote (DB/B, B, '' B)

- dark brown or black - black - spirochetes are UNSTAINED; background is black

Stains for Mycoplasma - Dienes

- blue

Stain for Bipolar Bodies (Yersinia pestis) - Wayson

- bipolar bodies: red

type of staining which actually provides coloration to the background of the smear while rendering the bacteria and covering structure such as capsule unstained.

INDIRECT/NEGATIVE/RELIEF STAINING

useful in the identification of medically important capsulated bacteria as well as capsulated strains of Cryptococcus spp. especially in cerebrospinal fluid sample in cases of meningitis.

INDIRECT/NEGATIVE/RELIEF STAINING

COLOR OF STAIN - Bacteria/ Structure (Capsule) - Background - INDIA INK OR NIGROSIN - CONGO RED - ANTHONY ## Footnote ('',^, B, R, P)

- UNSTAINED - COLORED/STAINED - Background is black; Streptococcus spp. - background is red - background is purple

Standard incubation hours

18-24 hours

inoculated plates are retrieved from the incubator and the colonial or cultural characteristics of the bacterial colonies that grew in each culture media for each specimen is examined

Plate reading

WORKFLOW IN BACTERIAL ID: ## Footnote (SC,DME,C,B.ID,BT, AST)

- specimen collection - direct microscopic examination - culture - bacterial id - biochemical test - AST

COLONIAL/CULTURAL CHARACTERISTICS (S.M.E.T.H.P.O.D)

- Size - Margin - Elevation - Texture or Consistency - Hemolytic Pattern - Pigmentation - Odor - Density

Relative size of the bacterial colony

SIZE

colonies less than 1mm

PINPOINT

about the same size of a pinhead

SMALL

slightly larger than a pinhead

MEDIUM

usually 6-8mm in diameter

LARGE

Appearance of the edge of the colony

MARGIN

circular without interruption

Smooth or entire

wavy edge

Undulate

crenated edge

Rough or Rhizoid

Lobulated edge

Lobate

branch-like edge

Fringed or filamentous

uneven rounded projections

Fingerlike

uneven length of projection w/ no definite shape

Irregular

Height of the colony

Elevation

ELEVATION no visible elevation or height

Flat

ELEVATION Slight elevation

Raised

ELEVATION dome shaped

Convex

ELEVATION depressed or concave center

Umbilicate (innie)

ELEVATION raised or bulging center

Umbonate (outie)

TEXTURE OR CONSISTENCY - Brittle or splinters: - Creamy or butyrous: - Dry and waxy: - Rough and warty: - Mucoid: ## Footnote (CC,B,SC,CA,W&SC)

- crumbling colony (e.g. Nocardia spp.) - butterlike (e.g. Staphylococcus spp.) - sticky colony (e.g. Diphtheroid) - cauliflower appearance (e.g. Mycobacterium spp.) - wet and sticky colony (e.g. Streptococcus pneumonia)

Exhibits the bacteria’s ability to lyse RBCs in the culture media (H.P)

hemolytic pattern

HEMOLYTIC PATTERN - Alpha - Beta - Gamma - Alpha Prime

- Clear zone around the colony; complete hemolysis - greenish or brownish zone around the colony; incomplete/partial hemolysis - no hemolysis around the colony - inner alpha hemolysis surrounded by an outer beta hemolysis

Blood agar plate = ?

Blood agar plate = Basal Medium + Blood (sheep’s blood, horse, etc.)

Ability of the bacteria to produce unique coloration of their colony

PIGMENTATION

PIGMENTATION - lime yellow - golden yellow - blue green - red - porcelain white - violet ## Footnote (ML,SA,PA,SM,SA,CV)

- micrococcus luteus - Staphylococcus aureus - Pseudomonas aeruginosa - Serratia marscesens - Staphylococcus albus - Chromobacterium violaceum

certain bacteria produce characteristic odor in culture media

Odor

ODOR - Unwashed stockings - Rancid Potato - Corn tortilla/fruity - Ammonia like - Freshly plowed field - Mousy/Mouse nest ## Footnote (S.SPP,SO,PA,A.SPP,N.SPP,H.SPP)

ODOR - Staphylococcus spp. - Serratia odorifera - Pseudomonas aeruginosa - Acinetobacter spp. - Nocardia spp. - Haemophilus spp.

optical property to pass light through the bacterial colony

DENSITY

DENSITY - Opaque - Translucent - Transparent

DENSITY - light won’t shine through the colony - light will shine through the colony - light shines through the colony

ANTIGENIC DETERMINATION BY SEROLOGICAL TYPING - O Antigen - H Antigen - K Antigen - Vi Antigen ## Footnote (C,F,C,ST)

- associated w/ the cell wall - associated w/ the flagella - associated w/ the capsule - specific capsular antigen of Salmonella Typhi

Capital first letter, not underlined, not italicized

Serotype