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BACTE LEC > WK 4 - micro, staph, strep > Flashcards

WK 4 - micro, staph, strep Flashcards

1
Q

MICROCOCCACEAE
(Type of pathogen)

A
  • Members of gram-positive cocci, aerobic or facultative
    anaerobes
  • Catalase (enzyme required to neutralize the toxic forms of
    oxygen) positive (except Stomatococcus)
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2
Q

significant members of micrococcaceaea

A

Members that are
significant among them are the: Staphylococcus,
Micrococcus, Stomatococcus

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3
Q

in clusters, bunch of grapes; Spherical bacteria that are
clustered together

A

Staphylococcus

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4
Q

are micrococcacea catalse positive or nefgative? what about its members?

A

Catalase (enzyme required to neutralize the toxic forms of
oxygen) positive (except Stomatococcus)

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5
Q

staphylococcus

A
  • Catalse positive
  • Non-motile
  • Facultative anaerobes
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6
Q

staphyklococcus are found where

A

normal inhabitants of skin and mucous membranes sila (anterior nares’ main residence)

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7
Q

Commonly cause human infections - because of the wide
variety of virulence factors that they can produce

A

staphylococcus

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8
Q

Species are differentiated by coagulase test,

A

staphylococcus S, the most
important being the coagulase positive S. aureus

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9
Q

in staphylococcus, Some animal species produce coagulase but are rarely
isolated from human samples

A

(ex. S. hyicus and S. intermidius

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10
Q

micrococcus type of pathogen

A
  • Opportunistic pathogens found only in
    immunocompromised patients
    of low pathogenic significance
  • May be isolated as a contaminant or as part of the normal microbiota
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11
Q

hen they grow, they give out a yellowish color
and they’re usually seen in tetrads

A

micrococcus luteus

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12
Q

stomatococcus

A
  • Part of the normal oral microbiota
  • Rarely isolated from infections
  • Colonies strongly adhere to the agar surface
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13
Q

There is only one species of Stomatococcus

A

There is only one species of Stomatococcus which is now
placed under Rothia genus.
o Rothia mucilaginosa is mostly associated with
prosthetic device infections

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14
Q

Staphylococcuus aureus infection

A
  1. skin and wound infections
  2. food posioning
  3. scalded skin syndrome or ritter’s disease
  4. TSS
  5. others : c. pneumonia, ostemyelitis, wound, abcess, skin infection
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15
Q

food posion in staphylococcus is due to

A

– Stapylococcal enterotoxins A and D
(heat-stable toxins pre-formed in food)

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16
Q

ritter’s disease is caused by

A

caused by
exfoliative/epidermolytic toxin and occur in newborns, and
in adults having chronic renal failure or are
immunocompromised

STAPHYLOCOCCUS

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17
Q

MORTALITY RATE OF SCALDED SKIN SYNDROME OR RITTER’S DISEASE

A

Mortality rate: Low in newborn, High in adults
having chronic renal failure for
immunocompromised

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18
Q

TOXIC SHOCK SYNDROM IS CAUSED BY6

A

S. aureus that
produces enterotoxin F (TSST-1)

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19
Q

There is a strong association within the use of
tampons

A

tss

There is a strong association within the use of
tampons and TSS and this can occur in both
sexes.

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20
Q

other infections of staphylococcus

A

o Staphylococcal pneumonia secondary to
influenza can occur
o Osteomyelitis can occur secondary to bacteremia
o Most outstanding association of S. aureus to
infection: Wound, abscesses and other skin
infections
o When you culture a wound specimen, abscess
and exudates and other purulent discharges you
will appreciate that at least 80% of those
conditions or samples will lead to or isolate a
staphylococcus aureus

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21
Q

virulence factors of staphylococcus

A
  1. coagulase
  2. protein a
  3. hemolysins
  4. exoenzymes
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22
Q

a bacterial enzyme that brings
about the coagulation of blood or plasma

A

coagulase

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23
Q

– a cellular component in the cell wall
that helps the bacteria to avoid phagocytosis
because of its ability to bind and neutralize IgG

A

protein a

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24
Q

yse RBCs, damage platelets and
even macrophages

A

hemolysin a

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25
Q

sphingomyelinase primarily C

A

hemolysin b

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26
Q

exotoxin little to polymorphonuclear
cells associated to Panton-Valentin
leukocydin

A

hemolysin y

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27
Q

east toxic among these cytolytic
toxins

A

hemolysin δ

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28
Q

allows the spread of
infection, by removing the cement that
glues connective tissues together, such
as the hyaluronic acid

A

Dehyaluronidase

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29
Q

facilitates S. aureus to
colonization of skin surface

A

lipase

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30
Q

exoenzymes found in staphylococcus

A

dehyaluronidase and lipase

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31
Q

methods of id in staphylococcus

A
  1. phenotypic = itusura
  2. immunological = serological analysis used in lab kits and serotyping
  3. genotypic = genetic techniques used to
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32
Q

in the lab, we will be just confined in just identifying S.
aureus into mostly

A

phenotypic means and a little of
immunological means.

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33
Q

what is positive reaction in coagulase test in staphylococcus

A

clot formed at the bottom of
the plasma tube indicates a positive reaction

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34
Q

cultural techniques fior staphylococcus

A

s – culturing on blood agar plates,
growing as round, smooth, white (sometimes yellowish)
and beta-hemolytic (completely lyses RBCs)
o You will see clearing at the bottom of the plate
due to RBC lyses
o 2 types in Blood agar plates: As white colonies
that are medium in size or, yellow or gold
colonies that are medium in size
o Beta-hemolytic colonies are best appreciated in
Sheep’s Blood Agar

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35
Q

catalse test for staphy

A

▪ S. aureus will be catalase positive
▪ Catalase positive – Uses hydrogen
peroxide.
▪ Catalase is needed to convert 2𝐻2𝑂2 →
𝑂2 + 𝐻2𝑂 (nontoxic form). The oxygen
that is present in the reaction will be
observed by the bubbling reaction, when
you subject the colonies to 3%
Hydrogen Peroxide (𝐻2𝑂2)
▪ S. aureus will be catalase positive,
converting H2O2 into its non-toxic for,
H2O and O2 (bubbling reaction)

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36
Q

2 types of coagulase test (Staphy)

A

Has 2 types: Cell Bound (slide method) and Free
Coagulase (tube method)

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37
Q

detects clumping factor in the surface of
bacterial cells. The plasma fibrinogen in
presence of the clumping factor will
convert fibrinogen into fibrin

A

▪ Cell-bound coagulase (slide method)

(Fibrinogen → clumping factor →
Fibrin)

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38
Q

detects thrombin-like molecule called
coagulase reacting factor (CRF). The
plasma contains the fibrinogen and the
bacteria react with the
Staphylocoagulase (extracellular
molecule that will react with CRF) which
is now a thrombin molecule that will
convert it into fibrin

A

▪ Free coagulase (tube method) –
n (Fibrinogen →
coagulase-CRF complex → Fibrin )

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39
Q

MEDIA USED FOR STAPHY

A

o For the selective media that you can use to culture S. aureus is basically sheep’s blood agar

o You can also use selective media when you are
dealing with heavily contaminated samples or
specimens like wound exudates, etc.

o You can utilize MSA (Mannitol Salt Agar), PEA (Phenylethyl Alcohol Agar) and CNA (Columbia NaladixicAcid Agar)

  • Use of selective media from heavily contaminated
    specimens (MSA, PEA, CNA)
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39
Q

MICROCOCCUS (pathogen type, loc)

A
  • Environmental organisms
  • Normal microbiota of skin and respiratory tract
  • Common contaminants
  • Coagulase-negative
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40
Q

Laboratory Identification of Micrococcus
(What tests)

A
  1. Modified oxidase test (Microdase Test)
  2. Bacitracin susceptibility (Taxo A Disc)
  3. Furazolidone resistance (100µg)
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41
Q

If the staphylococcus is not aureus, then most
probably it is .

A

CNS OR Coagulase-Negative Staphylococcus

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42
Q

CNS

A
  • Found as normal flora in humans and animal
  • Often are nosocomial infections
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43
Q

PREDISOSING FACTOR OF CNS

A

Predisposing factors:
o Catheterization
o prosthetic device implants
o immunosuppressive therapy

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44
Q

OTHER CNS

A

o S. epidermidis (normal skin microbiota)
o S. saprophyticus (associated with UTIs in
sexually-active, young females)

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45
Q

Laboratory Identification of CNS

A
  • Culture on sheep’s BAP
  • Various commercial identification systems may be
    used
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46
Q

Antibiotic susceptibility of Staphylococcal

A
  • P resistance is high, especially in S. aureus isolates (85-
    90%)
  • A common resistance is production of enzyme βlactamase (It will neutralize the effect of β-lactam
    antibiotics such as Penicillin and Cephalosporins)
  • Various β-lactamase resistant P have been developed.
    Methicillin is the most frequently used. Oxacillin is used for
    in-vitro susceptibility testing of methicillin resistance.
  • MRSA, MRSE (or ORSA/ORSE) are agents of serious
    nosocomial and community associated infectionS
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47
Q

Other characteristic feature to identify S. aureus
(Test)

A

o Mannitol fermentation – Positive
o DNAse test – Positive
o Beta-hemolytic on blood agar
o Golden yellow pigment

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48
Q

– S. aureus
produces yellow color colonies due to fermentation

A

Mannitol Salt Agar (Selective medium)

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49
Q

You can distinguish S. epidermidis from S. saprophyticus
by virtue of the

A

Novobiocin persistence tests

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50
Q

Coagulase test will identify
(staphy)

A

S. aureus being positive and
negative will somehow make you think of the other two
most common coagulase negative staphylococcus which
is the S. epidermidis and S. saprophyticus

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51
Q

streptococcus

A
  • Members are catalase-negative
  • Gram-positive cocci arranged in pairs or in chains
  • Facultative anaerobes (aerotolerant accrdg to Mahon)
  • Use of enriched medium or blood is necessary for their
    isolation
  • Hemolysis patterns are helpful in the identification
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52
Q

4 ways to classify streptococcus:

A

Nature of disease,
physiologic characteristics, hemolysis pattern, Lancefield
classification (typing of strep by carbohydrate found in
their cell wall)

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53
Q

Streptococcus pyogenes

A

Group a strep

  • Cell wall contains the Lancefield group A carbohydrate
  • Lancefield group of classification is the typing or the
    classification of streptococcus by the virtue of the
    carbohydrate groups found in their cell wall.
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54
Q

virulence factors of s pyogenes

A
  1. m protein
  2. streptolysin o
  3. streptolysin s
  4. hyaluronic acid capsule
    5.DNAse
  5. Spes A, B, C (erythrogenic toxin)
    7.protein f
  6. streptokinase
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55
Q

causes the bacterial cells to resist
phagocytosis by enabling it to adhere to mucosal
cells

A

m protein

56
Q
  • causes hemolysis of RBCs
    (antibodies can be produced, called ASO)
A

streptolysin o

  • causes hemolysis of RBCs
    (antibodies can be produced, called ASO)
57
Q

yses WBCs but not
immunogenic
▪ Antibodies are not created

A

streptolysin s

58
Q

responsible for red rashes in scarlet fever

A

o Spes A, B & C (Erythrogenic toxin) –

59
Q

– fibronectin binding protein, facilitates
adhesion to epithelial cells

A

protein f

60
Q

causes lysis of fibrin clots

A

streptokinase

61
Q

infections in s pyogenes

A
  1. pharyngitis (strep throat) and tonilitis
  2. skin infection (e.g. impetigo, necrotizing
    fascilitis, etc)
  3. scarlet fever
  4. rheumatic fever
  5. streptococcal tss
62
Q

o Pharyngitis (strep throat) & Tonsilitis

A

▪ These infections are frequently seen in
children ages from 5 to 15
▪ There is now a rapid strep test that can
be performed that can rapidly diagnose
strep throat

63
Q

you will see red rash would
appear on the upper chest and it will spread to
the trunk and extremities, following infection with
streptococcus pyogenes

A

scarlet fever

64
Q

r (consequence of untreated
pharyngitis) and glomerulonephritis
(immunocomplexes during episodes of
pharyngitis, antigen-antibody reaction)

A

rheumatic fever

65
Q

entire organ system shuts
down, happening during very severe
streptococcal infections where it disseminates
into different organ systems and eventually can
lead to death

A

streptococcal tss

66
Q

Laboratory Identification of S. pyogenes
(Test and what rxn)

A
  1. culture
  2. gram stian
  3. bacitricin susceptibility
  4. resistant to sulfamethoxazole
  5. pyridium oral test
67
Q

drug (antibiotic) very useful for
treating superficial skin infections but it is too
toxic for systemic use; polypeptide antibiotic
produced by Bacillus subtilis

A

bacitracin

68
Q

Interferes with the peptidoglycan synthesis of
bacteria

A

bacitracin.

positive siya if may zone of inhibition

69
Q

Examine for inhibition to sulfamethoxazole

A

Examine for inhibition. No inhibition means it is
S. Pyogenes

70
Q

Rapid method for presumptive identification of
bacteria based on the pyrrolidonyl arylamidase
enzyme

A

pyridium oral test

71
Q

broth method in pyr test for s. pyogenes qhat colo for positive

A

red

72
Q

test result for disc method

A

▪ PYR Test positive = S. Pyogenes (red
color)
▪ Negative – yellow color

73
Q

streptococcus agalactiae
(Type of hemolysis, pyr result, cell wall, sxt reaction, location)

A
  • β - hemolytic
  • Cell wall contains Lancefield group B carbohydrate
  • Group B Streptococcus or GBS (has sialic acid in
    capsules, it’s loss will result to loss of virulence)
  • Found as normal microbiota of the genitourinary tract
  • Resistance to SXT
  • PYR Negative
74
Q

group c and g streptococcal

A
  • Not commonly isolated
  • Hemolytic species in Lancefield group that are
    occasionally isolated from clinical specimens
  • Part of the normal skin microbiota
  • Β-hemolytic
  • These groups produce variety of infections including
    pharyngitis
  • Extensive use of biochemical reagents are needed to
    identify these groups
  • Serological tests were developed to identify the group
    carbohydrates in the cell wall for group C and G such as
    Latex agglutination tests to serotype group C and G
75
Q

virulence factor of streptococcus agalactiae

A

o Capsule – main component is sialic acid
o Hemolysin – lyse rbc’s
o Christie-Atkins-Munch-Peterson (CAMP) factor
enlarges the area of hemolysis
o Others (DNAse, hyaluronidase) have not been
shown to be factors in infection

76
Q

enlarges the area of hemolysis

A

Christie-Atkins-Munch-Peterson (CAMP) factor

77
Q

S. Agalactiae Infections

A
  • Neonatal sepsis soon after birth
  • Part partum fever and sepsis
78
Q

Laboratory identification of S. agalactiae
(Tests)

A
  • Culture – genitourinary tract swab, sheep’s blood agar
  • Gram’s stain – gram-positive in gram positive long chains,
    catalase-negative. In clinical specimen: they will appear in
    short chains
  • CAMP test positive – secreting a protein called CAMP
    factor (protein B)

o Christie-Atkins-Munch-Peterson (CAMP) – Test
use for presumptively identifying S. Agalactiae
(because it is the only strep that has the capability
to produce CAMP/Protein B)

  • Hippurate hydrolysis positive
79
Q

appearacne of s agalactiae

A

o It will appear as greyish white, mucoid colonies
in camp test positive

80
Q

camp test positive

A

o When placed perpendicularly with S. aureus, it
will form arrowhead hemolysis (enhanced
hemolysis) that synergistically reacts with the
beta-lysin of sphingomyelinase of S. aureus
o How: in a Sheep Blood Agar Plate streak a
colony of S. Aureus in the middle of the agar then
perpendicularly, streak the suspected S.
Agalactiae. Incubate overnight, then after 18-24
hours observe for the arrowhead hemolysis.
o Presence of arrowhead hemolysis = CAMP
Positive therefore it is a S. Agalactiaeo It will appear as greyish white, mucoid colonies

81
Q

– not only it can identify S.
agalactiae, it can also detect Campylobacter jejuni, Listeria
monocytogenes, and Gardnerella vaginalis. It detects the
ability of the organism to hydrolyse Hippurate.

A

Hippurate hydrolysis positive

82
Q

group c and g examples

A
  • Group C – S. equi, S. zooepidemicus and S. equisimilis
  • Group G – S. canis, S. anginosus, S. milleri
83
Q

group d streptococcal

A
  • Include S. bovis and S. equinus
  • Found as normal intestinal microbiota
  • May be agents of bacterial endocarditis, UTI’s, abcesses
    and wound infections
  • There are associations with bacteremia caused by S. bovis
    and GIT tumor. Isolation of S.bovis from the GIT indicates
    presence of tumor
84
Q

Laboratory Identification of Group D Streptococcus

A
  1. a or y.non hemolytic
  2. positive bile escutin test
  3. No growth at 6.5% NaCl broth
  4. PYR negative
  5. serotyping
85
Q

– positive reaction is production
of black precipitate due to hydrolysis of the reagent
esculin, in the presence of bile salts

A

Positive bile esculin test

86
Q

result of Positive bile esculin test

A

Positive – Presence of black precipitate due to
the hydrolysis of the reagent esculin

87
Q

enterococcus

A
  • Found in the intestinal tract
  • Most common is E. faecalis. Other members are E.
    faecium, E. avium, E. durans
  • Share characteristics of Group D, including the antigen D
  • Show resistance to several of the commonly used
    antibiotics

Has similar infections to Group D, the most common being
UTI

88
Q

Laboratory Identification of Enterococcus
(Tests)

A
  • BE positive, 6.5% positive, PYR positive
  • SXT resistant
  • Should be screened for high-level aminoglycosideresistant Enterococci (HLARE)
    o HLARE that are used are gentamicin, amikacin
    that are usually used to treat enterococcus
  • Vancomycin-resistant Enterococci (VRE) is a major
    concern
89
Q

e used are gentamicin, amikacin
that are usually used to treat enterococcus

A

high-level aminoglycosideresistant Enterococci (HLARE)

90
Q

highly resistant strains to most
antibiotics. That is why resistant strains cannot
just be treated with one antibiotic alone. It is
usually combination; synergistic treatment is
being done for enterococcal infection

A

Vancomycin-resistant Enterococci (VREVancomycin-resistant Enterococci (VRE

91
Q

viridians treptococci

A
  • Include those α-hemolytic streptococci (greenish
    hemolysis, partial hemolysis) that lack Lancefield group
    antigens and do not meet the criteria for S. pneumonia
  • Part of the normal microbiota of the oropharynx and the
    intestine
  • Fastidious and require increased CO2
  • Frequent cause of subacute bacterial endocarditis (SBE)
  • S. mutans, S. salivarus, S. anginosus, S. mitis, S. bovis –
    not hemolytic
  • NVS (nutritionally variant streptococcus) have been
    isolated from patients who have endocarditis and otitis
    media
  • Positive gram-stain, negative culture
92
Q

o Also known as pyridoxine-dependent (vitamin B6
dependent)
o Vitamin B6 is essential for their growth

A

NVS (nutritionally variant streptococcus) have been
isolated from patients who have endocarditis and otitis
media

v streptococci

93
Q

treatmetn of streptococcal and enteroccocal infections

A
  • Most species are susceptible to P
  • S. agalactiae is less susceptible than Group A and may
    require a combination of Amp and an aminoglycoside
  • Group D is susceptible to P
  • Enterococcus is usually resistant to P
  • Enterococcus is usually treated with synergistic
    Ampaminoglycoside combination
  • Pneumococcal isolates are treated with Erythromycin in
    case of P-resistant
  • Linezolid is being prescribed to VRE infections
94
Q

describe cell wall of s pneumoniae

A

The cell wall doesn’t have the usual carbohydrate group
by Lancefield. Rather, it has six layers composed of
peptidoglycan and teichoic acid attached to Nacetylmuramic acid, very similar to Group C Lancefield
groups

95
Q

s pneumoniae

A
  • Often part of the normal flora of the upper respiratory tract
    (URT)
  • Key virulence factor is an anti-phagocytic capsule
  • There are approximately 80-90 antigenic capsule types
  • An important human pathogen-causing pneumonia,
    sinusitis, otitis media, bacteremia, and meningitis

** Isolates may require increased CO2 (capnophilic)

  • Colonies are α-hemolytic
  • Young cultures produce a round, glistening, wet, mucoid,
    dome-shaped appearance

*Gram positive diplococci, having a halo meaning it is
encapsulated. The presence of numerous neutrophils or
polymorphonuclear cells. The presence of WBCs is an
indication of in going infection or inflammation

96
Q

Direct smears often reveal leukocytes and numerous
gram-positive diplococci with the ends being slightly
pointed, giving a lancet-shaped appearance

A

s pneumnoniae

97
Q

s pneumonieae grows on

A

rows on sheep’s blood agar as α-hemolytic, and βhemolytic when incubated anaerobically

Complex media such as brain-heart infusion agar (BHIA)
or trypricase soy agar (TSA) with 5% blood or chocolate
agar (CAP) are necessary for good growth

98
Q

Laboratory Identification of Streptococcus pneumonia

A
  • Lanceolate shape (Football shape)
  • Αlpha-hemolytic
  • Gram positive
  • Susceptibility to optochin (Taxo P)
  • Bile solubility test
  • Quellung test
99
Q

Inhibits production of ATP in microorganisms. It
makes the cell wall of pneumonia to become
fragile that when the cell membrane becomes
weak, the pneumonia lyses. ≥14mm diameter
zone of inhibition.

A
  • Susceptibility to optochin (Taxo P)* Susceptibility to optochin (Taxo P)
100
Q

They appear in colonies that are greenish or
alpha-hemolytic

A

optochin susceptibility test (taxo p)

101
Q

also an antibiotic that interferes with
production of adenosine triphosphate in
microorganism

A

optochin

102
Q

explain bile solubility test in pneumonia

A

Pneumonia is lysed by bile. Bile salts will lower
the surface tension between the bacterial cell
membrane and the medium. Once the cell
membrane is destroyed, it will accelerate the
organism’s autolysis

103
Q

o This test will differentiate S. pneumonia which is
soluble by bile from alpha hemolytic which is nonsoluble or insoluble to bile
o The reagent is sodium deoxycholate; for the test
tube is 2%, for plate test 10

A

bile solubility

104
Q

Microscopic test in which capsule surrounding
the pneumococci will appear like it is swelling

A

quellung test

o In some test, they would recommend to put
methylene blue to make it more visible

On microscopy, capsule (seen as clearing around
bacterial cell) becomes apparently swollen,
sharply delineated and refractile

105
Q

Streptococcus-like organisms

A
  • Aerococcus
  • Leuconostoc
  • Pediococcus
106
Q

Laboratory Identification of Streptococci

A
  • BAP hemolysis
  • Bile solubility – S. pneumonia is bile-soluble
    o There will be clearing in the test tube
  • Optochin (ethylhydrocuprein hydrochloride/Taxo P)
    susceptibility: ≥14mm with 5µg disk
  • Bacitracin (Taxo A) – S. pyogenes
  • Group A and B resistant to SXT
  • CAMP test presumptively identifies Group B
    Streptococcus – S. agalactiae
  • Esculin hydrolysis
  • 6.5% NaCl
  • PYR hydrolysis
107
Q

o Hemolytic pattern on blood agar plate
o For s. pneumonia it will be mostly alpha hemolytic

A

bap hemolysis

108
Q

Other: Laboratory Identification of Streptococci

A
  • LAP test (leucine aminopeptidase) helps differentiate
    Aerococcus and Leuconostoc from other Strep species
  • Serologic testing for the detection of C-Carbohydrate of
    the cell wall`
109
Q

helps differentiate
Aerococcus and Leuconostoc from other Strep species

A

LAP test

110
Q

for the detection of C-Carbohydrate of
the cell wal

A

Serologic testing

111
Q

types of hemolysis

A

alpha beta gamma or non

112
Q

there is a complete clearing of RBC,
because there is a complete lysis of RBC leaving a clear
space where the bacteria grew

A

beta hemolysis

113
Q

greenish because of the partial
hemolysis or incomplete hemolysis of the RBC, so there
are still some unused or not completely metabolized RBCs,
not completely lysed RBCs in the process

A

alpha hemolysis

114
Q

indicates staphylococcus

A
  • Pin-head colonies white colonies are indicative of
    staphylococcus
  • Pin-point translucent colonies having beta hemolysis is the
    usual morphology that you can see while dealing with
    streptococcus
115
Q

Two beta hemolytic streptococcus commonly isolated in
the lab

A

Streptococcus pyogenes (group A streptococci) o
Streptococcus agalactiae (group B streptococci)

116
Q

After the preliminary test (gram stain-oxidase), the next
thing that you should do is to differentiate the two beta
hemolytic (pyogenes and agalactiae) by

A

PYR test

117
Q

Among the beta hemolytic streptococcus that is PYR
sensitive or positive is

A

S. pyogenes
o If positive, the color would be violet

118
Q

After bacitracin sensitivity, if it is sensitive then it is
??? . Once it is PYR positive, you are confirming that
your isolate it

A

After bacitracin sensitivity, if it is sensitive then it is
pyogenes. Once it is PYR positive, you are confirming that
your isolate is pyogenes

If it is resistant, possibly it is S. agalactiae. You do CAMP
test, if it is positive (arrow head hemolysis) then it is group
B or S. agalactiae.

119
Q

If Hippurate hydrolysis is positive, then it is also
confirmatory test to

A

S. agalactiae

120
Q

To distinguish S. pneumonia to Viridans streptococci, you
do

A

Optochin sensitivity test

121
Q

To further identify
Pneumococcus, to confirm it is S. pneumonia. You do

A

capsular swelling test, bile solubility test (clearing

122
Q

General Characteristics
of neisseria and moraxella

A
  • Gram-negative cocci often in pairs
  • Kidney-bean shaped, capnophilic that will require 10-20% of carbon dioxide
  • Oxidase-positive, catalase-positive
  • Natural habitat of Neisseria is the mucous membrane of
    the urogenital tract
  • Moraxella and some Neisseria, they are inhabitants of the
    mucous membrane of the respiratory tract
  • Mucous membrane of urogenital tract (Neisseria)
  • Mucous membrane of upper respiratory tract (Moraxella
    and some Neisseria)
123
Q

Differentiation of nerisseria and moxarella is based on

A

acid production from
carbohydrate utilization test

124
Q

specimen collection for neisseria annd moraxella

A

Proper specimen collection is
essential for successful
isolation - Specimens should be kept at room temperature
and plated as soon as possible

It is advisable that when you collect samples esp.
vaginal samples or urethro swab samples or
gonococcal infections. Dacron and Rayon swabs
are referred for collections because the use of
cotton swabs will allow them to ba absorb and
you will end up having negative results.

125
Q

growth requirements of neisseria nad moraxella

A

Proper specimen collection is essential for successful
isolation - Specimens should be kept at room temperature
and plated as soon as possible

126
Q

Pathogenic Neisseria gonorrhoeae Virulence factors

A
  • Receptors for human transferrin
  • Capsule – polysaccharide capsule
  • Pili (T1-T5)
    o Piliated types (T1, T2) - Presence of pili indicate
    pathogenicity.
    o Non-piliated (T3-T5)
  • Cell membrane proteins (Protein 1-3)
  • Lipo-oligosaccharide (LOS) – antigenic variation
  • IgA protease – render immunoglobulin A inactivated
127
Q

cell membranes of neiserria

A

o Protein I (por) – channel or pore for nutrient and
waste diffusion
o Protein II (opa)– opacity and facilitate adherence
to phagocytic and epithelial cell
o Protein III (rmp) – reaction-modified protein
(RMP) blocks serum IgG; antibodies will not work

128
Q

gonorrhea

A

o Infected males show symptoms of burning and
discharge from the urethra
o Females may be asymptomatic but can lead to
pelvic inflammatory disease (PID)
o May cause sterility in males and females

129
Q

Neisseria gonorrhoeae Infections

A
  • Gonorrhea
  • opthalmia neonatorum
  • gram stain and location (IC/EC)`
130
Q

Laboratory Identification of N. gonorrhoeae

(CHCARACTERISTICS)

A

o Gram-negative diplococci located intracellularly
or extracellularly of neutrophils
o Very important for identifying sexually disease
involving male patients
o Gram stain positive is correlated 95% strong
presumptive evidence of gonorrhea when the
gram stain is positive

131
Q

LAB IDENTIFICATION OF N. GONORHHOEAE

A
  • Culture using selective agars (Thayer Martin, MTM,
    Martin-Lewis and New York City) packaged in selfcontained transport systems such as JEMBEC, Transgrow, GonoPak – allow to have 5% CO2 so they won’t die
  • Produces acid from glucose utilization (fermentation) but
    not for maltose, sucrose, and lactose
  • Colonies are flat, gray, smooth and glistening
  • Other identification Methods:
    o Rapid carbohydrate degredation tests
    o Chromogenic substrates
    o Immunologic assays
    o Nucleic acid assays
  • Carbohhydrate Utilization Test
132
Q

CARBOHYDRATE UTILIZATION TEST

A

o Confirmatory test that you could do to identify the
different species of Neisseria
o Using CTA (cysteine tryptic agar) containing 1%
each of these sugars (glucose, maltose, sucrose,
lactose)
o The indicator is always phenol red, when they are
able to ferment the sugar. The acids that will be produced during fermentation will convert the
phenol red into yellow color

133
Q

Neisseria meningitidis infections

A
  • Primarily these infections are transmitted by droplets,
    onset is abrupt
  • Onset of these infections, you will experience headaches,
    stiff neck and fever. Some will have pedicle lesions that
    could be present.
  • Meningococcal meningitis
  • Meningococcemia (sepsis)
134
Q

The brain substance will be inflamed and it can
also progress to BIC, septic shock and therefore
later on it can also lead to hemorrhage of the
adrenal gland (water house friderichsen
syndrome)

A
  • Meningococcal meningitis
135
Q

Virulence factors
OF NEISWERRIA meningitis

A
  • Pili
  • Capsule - Encapsulated strains of N. meningitidis are
    ABCYNW135
  • POR, OPA, RMP
  • LOS endotoxin
136
Q

Moraxella catarrhis

A
  • Part of the normal URT
  • It grows on sputum sample
  • It is interpreted as non-pathogenic
  • It includes in the family Moraxella acinetobacter and
    Moraxella citrobacter
  • May cause otitis media, sinusitis, and respiratory infections
  • Grows on blood, chocolate, and nutrient agars unlike
    Neisseria that are very fastidious
  • Able to reduce nitrate to nitrite
  • Produces DNAsE
137
Q
  • Pathogenic Neisseria are subjected to grow on a
A

selective
agar

138
Q
A

BACTE LEC (7 decks)

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