P1 | Bacterial Morphology (LECTURE) Flashcards
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)
The staining procedure separates almost all medically relevant bacteria into two general types:
- Gram Positive
- Gram Negative
Common bacterial cellular morphologies:
(C.C.B.F.C.S)
- Cocci (circular)
- Coccobacilli (ovoid)
- bacillus (rod shaped)
- fusiform (pointed end)
- curved
- spiral shapes
Microscopic Shapes
- found in ocean sediment
- has a diameter of 0.1 to 0.3 mm.
Thiomargarita namibiensis
Microscopic Morphology of Bacteria
(COCCI)
(C.C.P.T)
- In clusters
- In chains
- In pairs
- In tetrads
Microscopic Morphology of Bacteria
(BACILLI)
(C.B.F.P)
- Coccobacilli
- Bacilli of various sizes (pleomorphism/pleomorphic bacteria)
- Fusiform bacilli
- Palisading (parallel)
Microscopic Morphology of Bacteria
(SPIROCHETES)
- round or spherical shaped bacteria.
- The resulting arrangement of cocci depends on the PLANE of DIVISION
Cocci (Coccus)
(DIPLOCOCCUS OR DIPLOCOCCI)
All diplococci appears to be two cocci adjacent to each other except:
- Neisseria spp.
- (Except: Neisseria weaveri and Neisseria elongata)
kidney or coffee bean shaped diplococci
Neisseria spp.
- (Except: Neisseria weaveri and Neisseria elongata)
Is Neisseria spp.
- (Except: Neisseria weaveri and Neisseria elongata) gram positive bacilli or gram negative bacilli?
Gram Negative Bacilli
flame/lancet shaped diplococci
(SP)
Streptococcus pneumoniae
Is Streptococcus pneumoniae a gram positive or gram negative?
Gram positive
What is the plane of division for “DIPLOCOCCUS/DIPLOCOCCI”?
Coccus is divided one (1) plane of division
COCCI IN CHAINS
Plane of division?
e.g Streptococcus spp.
Coccus is divided by one (1) plane of division but continuously dividing it.
Coccus in packets of four (4)?
Tetrad/s
What is the plane of division for “TETRAD/S”?
Coccus is divided two (2) planes of division.
Example of a Tetrad?
Micrococcus tetragena
Coccus in cubical packets of eight (8)?
Sarcina/e
What is the plane of division for “SARCINA/E”?
Coccus is divided three (3) planes of division in a regular pattern
Example of a Sarcina/e?
(M.L)
Micrococcus luteus
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
rod shaped, cylindrical, or elongated bacteria
BACILLUS (BACILLI)
BACILLI MORPHOLOGY
rod shaped bacillus
Single Bacillus
BACILLI MORPHOLOGY
bacillus in pair
Diplobacillus
BACILLI MORPHOLOGY
bacillus in chains
Streptobacillus
BACILLI MORPHOLOGY
bacillus that are small, short, stout/plump
(CB)
Coccobacillus
BACILLI MORPHOLOGY
Small and short bacillus arranged in school of fish, rail road track, or fingerprint pattern in stained smear
(H.D)
Haemophilus ducreyi
Causative agent of Soft changre/chancroid (STI)
(HD)
Haemophilus ducreyi
Large, square cut-ends, spore forming bacillus
- Arranged in chains
(BA)
Bacillus anthracis
causative agent of
anthrax
Bacillus anthracis
Large, rounded ends, non-spore forming bacillus
- Arranged in chains
(FB.SPP)
Fusobacterium spp.
anaerobic bacteria which chiefly found as a normal flora in the gastrointestinal tract (GIT)
(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
(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)
(S.M)
Spirillum minor/minus
Loosely twisted spiral
- Resembling a stretched spiral
(B. spp)
Borrelia spp.
causative agent of relapsing fever and lyme disease
(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
(L.I)
Leptospira interrogans
imparts an artificial coloration
Staining
The four categories of staining:
(D.D.S.I)
- Direct/simple stain
- Differential Stain
- Selective/special stain
- 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?
- Ziehl-Neelsen Staining method
- 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)
- Pappenheim stain
- 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
(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
(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
(G,R,G)
- Green
- Red
- Green
Stains for Flagella
(L,G,S,F-C)
- Leifson
- Gray
- Silver
- Fisher-Conn
important component in flagellar stain which coats, swells, precipitates the flagella enhancing its visualization
(T.A)
TANNIC ACID
Stains for Rickettsia
- CASTAÑEDA
- MACHIAVELO
- GIEMSA
(B,R,B)
- blue
- red
- blue
Stains for Chlamydia
- GIMENEZ
- MACHIAVELO
- GIEMSA
(R,R,P)
- red
- red
- purple
Stains for Spirochetes
- Fontana-Tribondeau
- Levaditi Silver Impregnation
- India Ink Negative Stain
(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
(‘’,^, 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:
(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:
(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
(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
(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
(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