Jt Microbiology - Bacteriology I

Front 1

Define:
Obligate aerobe
Obligate anaerobe
Facultative anaerobe
Aerotolerant
Microaerophilic

Which is most common?

Back 1

Obligate aerobe; Needs O2 to grow

Obligate anaerobe: O2 is toxic

*Facultative anaerobe: grows in both environments

Aerotolerant: Anaerobe not killed by O2

Microaerophilic: requires CO2 to grow

Front 2

Give an example of an aerotolerant bacteria

Back 2

Clostridium tertium

Front 3

Define:
Lag phase
Log phase
Stationary phase

Back 3

Lag phase: slow growth. >24h old

Log phase: Best growth. 18-24h

Stationary phase: Good for transportation (ex: boric acid in urine)

Front 4

Preferred collection for N gonorrhea?

Back 4

Charcoal swap
DO NOT REFRIGERATE

Front 5

Transport media for swabs

Back 5

Stuart or Aimes transport media. Preserves viability

Front 6

Urine collection

Back 6

in boric acid, refrigerate
MUST CULTURE WITHIN 24h

Front 7

Gram stain steps

Back 7

1. Crystal violet
2. Iodine (mordant)
3. Acetone (decolorizer)
4. Safranin (counterstain)

Front 8

Criteria for sputum rejection

Back 8

>25 squames/lpf

* can still accept for AFB and fungus, just no good for bacteria (spit contamination)

Front 9

Indications for CSF baterial antigen test

Back 9

Best in partially treated patients. Always culture also.

Front 10

Organisms detected with CSF bacterial antigen test? Why is this test falling out of favor?

Back 10

HIB,

N mening,

S pna,

GBS

Worked best for HIB, now with vaccine we don't see much. Low sens & spec with others.

Front 11

What is a selective media?

Differential media?

Which type is MacConkey?

Back 11

Selective: something added to the media that selects for certain growth (ex. PEA for gpc)

Differential: something added to ID with color (chromagar)

MacConkey is BOTH

Front 12

Back 12

Staphylococcus

gpc in clusters

Front 13

What test is this?

Back 13

Catalase test.

Staph is +, strep is -

* blood has innate catalase activity, beware contamination with sheep blood agar

Front 14

What test is this?

When should it be read?

Back 14

Coagulase test.
rabbit plasma + organism, 35C.
Read at 4h AND at 24h.

S. aureus is +
"coag-negative-staph" are -

Front 15

What is the major virulence factor for S aureus?

Back 15

Protein A

capsular polysaccharide

coagulase

toxins

hemolysins

Front 16

What diseases are caused by S aureus?

Back 16

Toxic shock syndrome (TSST1)
Scalded skin syndrome
Food poisoning
Endocarditis
Soft tissue infection (Panton valentine leucocidin)

Front 17

Mannitol salt agar. What ferments mannitol and turns it yellow?

Back 17

S. aureus tolerates 7.5% salt and ferments mannitol

Front 18

What organism has mauve colonies on chromagar?

Back 18

S aureus

Chromagar + oxacillin = surveillance screen for MRSA

Front 19

What coag neg staph is responsible for subacute endocarditis?

What is its new claim to fame

Back 19

S. epidermidis (normal skin flora)


BIOFILMS!

Front 20

What coag neg staph is responsible for UTIs in reproductive-age females?

How to ID?

Back 20

S. saprophyticus

NOVOBIOCIN RESISTANT by KB disk

Front 21

What coag neg staph is responsible for line-related sepsis?

Back 21

S. hemolyticus

Front 22

What is the only coag-neg staph that hemolyzes on SBA and therefore can be confused with S. aureus?

Back 22

S. hemolyticus

Front 23

Back 23

Micrococcus

gps in TETRADS

Front 24

Back 24

Micrococcus

yellow pigment

normal flora, rarely causes infection

Front 25

ID of micrococcus

Back 25

bacitracin susceptible
modified oxidase (microdase) +
does NOT ferment glucose (vs staph)

Front 26

Organism?

How to ID vs. staph?

Back 26

Streptococcus
gpc in chains

catalase NEGATIVE

Front 27

Novobiocin KB disk test

Back 27

R; Resistant = Staph saprophyticus

L: susceptible = Staph epidermidis

Front 28

Beta-hemolytic streps

Back 28

Lancefield groupings: Group ABCFG strep

Based on C carbohydrate in cell wall

Front 29

GAS

Back 29

S. pyogenes (Group A beta-hemolytic strep)

Bacitracin susceptible

SXT resistant

PYR positive

no resistance to penicillin

Front 30

test? organism?

(Disk = A)

Back 30

GAS = s. pyogenes
BACITRACIN SENSITIVE

A stands for "GAS" not bacitracin...

Front 31

What test is this? Which is GAS?

Back 31

PYR test.

GAS is PYR + and turns RED

Front 32

What organism is universally susceptible to penicillin?

Back 32

GAS = S. pyogenes

Front 33

Major virulence factor of GAS?

Diseases?

Back 33

M PROTEIN (vs staph: protein A)
Also: capsule, exotoxins, streptolysin O & S

Pharyngitis Impetigo Erysipelas Cellulitis
Puerperal sepsis Toxic Shock

Front 34

What organisms causes rheumatic fever and glomerulonephritis?

Back 34

GAS

Front 35

Which strep is the LEAST beta-hemolytic?

Unique testing characteristics?

Back 35

GBS

Camp test +
Rapid hippurate hydrolysis

Front 36

How to ID GBS vs. listeria

Back 36

Both look similar on culture; affect same patient population

but GBS is CATALASE NEGATIVE, listeria is +

Front 37

Unique test for GBS? Which is GBS?

Back 37

Camp test

S. aureus strain with camp factor perpendicular to GBS; intensifies GBS toxin production.

Top one was GBS, looks like an arrow = camp test +

Front 38

Rapid hippurate hydrolysis. Which is GBS?

Back 38

purple = positive
read at 4 hrs

Front 39

What test do most people do for GBS?

Back 39

Lancefield groupings (serology?)

Front 40

important gamma-hemolytic streps

Back 40

Enterococcis
GDS not enterococcus

Front 41

ID of enterococcus

Back 41

BILE ESCULIN +
6.5% SALT +
PYR + (~GAS)

Front 42

All enterococci are resistant to:

Back 42

Cephalosporins
Clindamycin
Bactrim

Front 43

Test?

Back 43

Bile esculin (enteroccus is +)

Front 44

GDS (not enterococcus) vs enterococcus?

Back 44

Both are Bile esculin +!
GDS is salt negative, PYR negative

Front 45

GDS

clin sig?

always susceptible to?

Back 45

S. bovis

In blood = GI ca

PCN

Front 46

Back 46

Strep pneumoniae

gpc lancet shaped cocci, with capsule

Front 47

Back 47

S. pna

Front 48

alpha-hemolytic strep

Back 48

S. pneumoniae
S. viridans (many types)

Front 49

Virulence factor in S. pna

Back 49

polysaccharide capsule (resists phagocytosis)

Front 50

S. pna ID in lab?

Back 50

Bile soluble on SBA (sodium deoxycholate)
OPTOCHIN SENSITIVE

Front 51

resistance mechanism of S. pna to pcn?

Back 51

Acquired resistance by PBPs

Front 52

Quellung reaction

Back 52

biochemical reaction in which antibodies bind to the bacterial capsule of Streptococcus pneumoniae, Klebsiella pneumoniae, Neisseria meningitidis, Haemophilus influenzae, and Salmonella. The antibody reaction allows these species to be visualized under a microscope. If the reaction is positive, the capsule becomes opaque and appears to enlarge.

Can type the ~90 types of S. pna to see if covered by vaccine

Front 53

What is optochin?

Back 53

a chemical

=ethyl hydrocupreine hydrochloride

Front 54

Optochin disk test. Which is S. pna?

Back 54

the one on the L; need 14mm of inhibition.
R is S. viridans

THE DISK HAS "P" ON IT, NOT AN O! (for pneumococcus)

Front 55

Name some viridans streps.

ID pattern?

Dz?

Back 55

NF in mouth

S. mutans (tooth decay)
S. sanguis
S. mitis

S. salivarius

Bile INSOLUBLE, Optochin RESISTANT

Bile esculin negative

Cause of 30% subacute endocarditis, in mitral valve disease

Front 56

More virulent group of alpha-hemolytic strep?

Back 56

anginosus group: anginosus, constellatus, intermedius

Normal oral flora but more virulent than “normal” viridans Strep perhaps due to capsule

Deep tissue abscesses, endocarditis, intraabdominal infections

Front 57

Blood culture grows gpc, but doesn't grow on media

Back 57

Nutritionally variant strep (B6 deficient)
(Abiotrophia, Granulacatilla)

Front 58

gpc that will not grow on regular media, but grows next to staph

Back 58

nutritionally variant streptococcus

(NOTE: This also works for haemophilus so look for gram stain! There is sufficient hemin in blood for growth of Haemophilus, but the medium is insufficient in NAD. S. aureus produces NAD in excess of its own needs and secretes it into the medium, which supports the growth of Haemophilus as satellite colonies.

Front 59

Sugar fermentation of GNCs

Back 59

N. gonorrhoeae Gluc + Mal - Lac - Suc -
N. meningitidis Gluc + Mal + Lac - Suc -
N. lactamica Gluc + Mal + Lac+ Suc-
M. catarrhalis all negative, Dna’ase +

Front 60

Back 60

Neisseria
gram negative diplococci

Front 61

Can you dx neisseria on gram stain alone?

Back 61

Trick question. Depends on sex
Females: NO! Acinetobacter can look very similar and is normal flora in female genital tract

Males: Yes. there is no normal GU flora that looks like this

Front 62

organism?

Back 62

N gonorrhea

Ferments glucose only (YELLOW!)

Front 63

T/F: All neisseria are oxidase positive.

Back 63

TRUE

Front 64

Back 64

Waterhouse Friederichsen syndrome
Adrenal necrosis and hemorrhage associated with NEISSERIA MENINGITIDIS

Front 65

What type of N mening is causing epidemics in college dorms?

Back 65

Type C

Front 66

What immunodeficiency predisposes to N mening?

Back 66

Complement 7, 8, 9 deficiency (MAC complex!)

Front 67

Prophylaxis for N mening? Treatment?

Back 67

Proph = rifampin

Thx = PCN

Front 68

transport for N gon?

Back 68

Charcoal swab

Front 69

Treatment for PPNG?

Back 69

(penicillinase-producing N gon)
Ceftriaxone
Quinolone

Front 70

sputum

colonies?
ID?

Back 70

moraxella catarrhalis

GNCs in diplococci. causes pneumonia, OM, sinusitis, eye.

HOCKEY PUCK COLONIES
OXIDASE +
DNAase +

Front 71

ID?

Back 71

Corynebacterium
GPBs, chinese letters

CATALASE +
NO SPORES

Front 72

Methylene blue stain of culture growing on Loeffler slant

What is it?
What is in Loeffler slant?

Back 72

Metachromatic granules of Corynebact diptheriae

Loeffler slant has EGG in it

Front 73

Cysteine tellurite agar
Black colonies with brown halo

Back 73

Corynebacterium diptheriae

Front 74

GPB on KB disk that is ONLY susceptible to vancomycin and tetracycline

Back 74

Corynebacterium jeikeium

(normal skin flora; plastic catheters & lines. resistant to most antibiotics)

Front 75

Alkaline encrusted cystitis

Back 75

corynebacterium urealyticum
rare
Pure culture of GPB that is rapid urease +

Front 76

Only spore-forming gpb?

Back 76

Bacillus

Clostridium

Front 77

Back 77

Bacillus
GPB boxcar shaped

Front 78

Back 78

Black eschar skin lesion of bacillus anthracis

Front 79

Non-hemolytic,

non-motile,

PCN sensitive

Back 79

Bacillus anthracis
Medusa head colonies on SBA

Front 80

Fried rice food poisoning within 1-6h

Back 80

B. cereus!

Emetic endotoxin

Front 81

B cereus vs B anthracis?

Back 81

B cereus: Beta hemolytic & motile!

B anthracis: Not hemolytic and not motile!

Front 82

Back 82

Listeria
small gpb, beta-hemolytic (~to GBS but catalase+!)

Front 83

What is on the right?

Back 83

Listeria.

Motile.

Likes oxygen so grows near the top.

Will grow better at 25C than 35C.

Loves cold - grows at 4C

Front 84

Endocarditis in drug users

Catalase negative

Alpha hemolytic

Back 84

Erysipelothrix rhusiopathiae
catalase negative gpb

Front 85

What is the ONLY GPB that makes H2S?

Back 85

Erysipelothrix rhusiopathiae

Front 86

GPB that causes pharyngitis
(and is beta-hemolytic, and catalase negative!)

Back 86

Arcanobacterium hemolyticum

Confuse with S.pyogenes (GAS) but this is a GPB!

Front 87

Transport media for anaerobes

Back 87

eSwab or vial (port o cult)

no oxygen

Front 88

Transport for CSF for bacterial culture

Back 88

sterile container, room temp or incubate at 35 degrees

Front 89

How to judge quality of gram stain

Back 89

Polys

if blue --> under-decolorized

if washed out --> over-decolorized

Front 90

Broth tubes are good to detect...

Back 90

low numbers of bugs that might not grow on agar - sterile body fluids

Front 91

What is PEA (polyethyl acohol)?

Back 91

added to media to select for GPC

Front 92

MacConkey agar

Back 92

Differential and selective

Only gram negatives will grow

Pink = lactose fermentation

Clear = lactose nonfermenter

Front 93

GBS susceptible to...

Back 93

penicillin

Front 94

E faecium vs E faecalis

Back 94

faecium = arabinose +

faecalis = arabinose -

Front 95

Enterococcus: natural resistance to ...

Back 95

cephalosporins

Treat with ampicillin or vancomycin

Front 96

Agar to screen for VRE

Back 96

Bile esculin

Front 97

Gluc + Mal - Lac - Suc -

Back 97

N. gonorrhoeae

Front 98

Gluc + Mal + Lac - Suc -

Back 98

N. meningitidis

Front 99

Gluc + Mal + Lac+ Suc-

Back 99

N. lactamica

Front 100

all sugars negative, Dna’ase +

Back 100

M. catarrhalis

Front 101

What % of N gonorrhoeae disseminate?

Back 101

10-20% ascend

0.5% disseminate

Front 102

HOCKEY PUCK COLONIES

OXIDASE +

DNAase +

Back 102

Moraxella catarrhalis

Front 103

M catarrhalis resistance

Back 103

Ampicillin by beta-lactamase

Front 104

Toxin for Coryne diphtheriae

Back 104

phage mediated toxin

Detected by Elek immunoprecipitation

Front 105

Back 105

Diphtheria