Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MLS503 > Week 4 > Flashcards

Week 4 Flashcards

1
Q

List the genera that are considered pathogenic cocci.

A

-staphylococci G+ cocci, clusters, uniform
-Stereptococci, G+ cocci, chains, unifiorm
-Neisseria, G- diplococci hamburger buns, many sizes
-moraxella G- diplococci hamburger buns, many sizes flat adjacent sides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define the terms pyogenic, suppurative, and purulent exudate

A

puss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the most frequently isolated GROUP of organisms in the clinical lab, part of normal flora and are opportunistic pathogens

A

Pathogenic cocci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

List the genera and species of the Family Micrococcaceae. 2 genus, 5 spp

A

Fam-micrococcaceae
Genus:
- staphlococcus
- Micrococcus
Species:
- S. aureus
-S. epidermidis
- S. saprophyticus
- S. haemolyticus
- S. luteus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

List the major characteristics of Micrococcaceae and explain the significance of each in the clinical lab. Staphylococcus Identification

A

-All G+ cocci that form clusters
-Med sized dome shaped colonies on SBA (smaller than G - rods) white colonies
-All are catalase positive (test differentiates staphs from streps)
-common normal flora (except in vagina and small intestines)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Catalase test

A

3-5% H2O2 on slide, with loop 3-4 colonies, cat pos= rapid profuse bubbles
Wimpy bubbles= cat neg also RBC’s give fasle positive
Do not cool loop in agar, must have iso colonies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What test is definitive for S. aureus (only produced by S. aureus)?

A

Coagulase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Coagulase Test 4 methods

A

Rabbit plasma- fibrinogen= fibrin
Rapid slide- spot test, detects cell bound coagulase, some strains of S. aureus
Tube method- 4hr to O/N, detects free extracellular coagulase, must be done id rapid slide is neg, all strains
Rapid latex tests- spot text, staphyloslide- fibrinogen= fibrin and IgG= protein A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

S. aureus Colony morph, hemolysis, MSA, CNA, MAC, novo

A

-Colony morph SBA- med white to buttery color
-Hemolysis beta or gamma cannot use for ID
-MSA- man pos (48hrs)
-CNA- white growth
-MAC- NG
-Novobiocin- zone of inhibition or -susceptible S
- coag staph latex- pos

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

S. epidermidis Colony morph, hemolysis, MSA, CNA, MAC, novo

A

-colony morph SBA- white dome shape
-hemolysis- almost always gamma or no hemolytic
-MSA- man neg both 24 and 48
-CNA- white growth
-MAC- NG
- novobiocin- susceptible
- coag staph latex-neg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

S. saprophyticus Colony morph, hemolysis, MSA, CNA, MAC, novo

A

-colony morph- white and yellow
-hemolysis- almost always gamma or non hemolytic
-MSA- man neg or weak man pos at 24 or 48hr
-CNA- white or yellow growth
-MAC- NG
- novobiocin- Resistant
-coag staph latex- neg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Staphylococcus Flow Chart

A

look at flow chart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

List four major groups of infections/diseases caused by S. aureus. 4

A

skin infections
wounds
dissemination from local infections
toxin mediated diseases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Skin infections causes by S. aureus

A

furuncles/ carbuncles
impetigo- bullous 80%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Dissemination from local infection by S. aureus 6

A

Septicemia- infection in bloodstream with symptoms
Bacteremia- presence in bloodstream w/o symptoms
Osteomyelitis: inflammation on bone marrow
Pneumonia- infection in lungs
Endocarditis- drug users, heart infection
Meningitis- in meninges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Toxin mediated diseases by S. aureus 3

A

-Toxic shock syndrome-traps S. aureus TSST-1
-Food poisoning- food left out, enterotoxins A & D= preformed toxins- 2-8hrs later
-Staphylococcal scalded skin syndrome
Ritters disease
Exfoliative toxin

17
Q

Invasive mechanisms by S. aureus 6

A

Coagulase- clumping factor
Hyaluronidase- hyaluronic acid breaks down tissue - spreading factor
Protein A- call wall protein unique to S. aureus- prevents phagocytosis 30% of protein A excreted by cell
Lipase- breaks down oils- all stap spp produce this
Staphylokinase- dissolves fibrin strands
Beta lactamase- breaks down penicillin, present in 90% of S. aureus strains

18
Q

Toxin production by S. aureus

A

Enterotoxins A-E: affects GI tract
Exfoliative toxin: epidermolytic toxin
Toxin 1: TSST-1

19
Q

Cytolytic toxins

A

alpha, beta, gamma. Toxin for many cells including leukocytes, macrophages, erythrocytes, platelets

20
Q

Coagulase Negative Staphylococcus (CoNS) 4

A

S. epidermitis
S. saporphytuc
S. haemolyticus
S. lugdunensis

21
Q

S. epidermidis

A

The most common aerobic bacteria on skin
Causes 70-80% CoNS infections
Low virulence-opportunistic pathogen
Causes nosocomial infections
Hospital inquiries infections
Plastic prosthetic devices- slime layer, adherence factor

22
Q

S. saprophyticus

A

UTI’s- adhere to epithelial cells lining urogenital tract
cystitis

23
Q

S. haemolyticus

A

NF occasionally seen in clinical samples

24
Q

S. lugdunesis

A

NF on skin, capable of causing osteomyelitis and septicemia, most known for causing aggressive endocarditis

24
Q

List the genera in the family Streptococcacae 2

A

-streptococcus
-enterococcus

25
Q

List the species of the genus Streptococcus. 7

A

-S. pyogenes
-S. agalactiae
-S. pneumoniae
-Viridans: S. mutans, S. sanguis, S. salivarius, S. mitis, S. milleri group
-Enterococcus faecalis
-E. Faecium
-Group D streps

26
Q

List the laboratory characteristics of Streptococcus used to identify Streps.

A

Gram stain reaction: G pos cocci
Cellular morphology:
S. pyogenes: G pos cocci/ chains
S. pneumoniae: G pos diplococci
Colony morphology
Nonpigmented
Ground glass- translucent
Hemolysis- beta, alpha gamma all used for ID
Serological groupings- lancefield groups
Normal flora- not found in outer ear

27
Q

Explain the Lancefield classification scheme and the basis of the three categories.

A

Based on components found in cell wall
Caused diff serological reactions- 3 categories
-C carbohydrates: 5 groups A,B,C,F,G
-Lipoteichoic acid: group D: no C carbohydrate, look for LTA instead
-Non-lancefield neither C carbo;s of LTA serotypes
S. pneumoniae
Viridans

28
Q

Which Strep spp are Beta hemolytic?

A

S. pyogenes (Group A)
S. agalactiae (group B)

29
Q

Which Strep spp are alpha hemolytic?

A

S. pneumoniae
Viridans
Group D Streps: S. bovin, S. equinus, E. Faecalis, E. faecium

30
Q

Strep Pyogenes or Group A tests and results: hemolysis, bacitracin, pry, rapid Gr A strep kit, latex agglutination kit

A

Hemolysis- beta, due to streptolysin S and O (S=oxygen stable, O= oxygen labile)
Bacitracin- A disk- bas S or susc
PYR- pos
Rapid Gr A strep test- pos
Latex agglutination kits- pos

31
Q

Explain how to test for streptolysin O, when to use it, and how to interpret it.

A

Stab agar with organism, beta hemolysis= pos

32
Q

Positive for group A strep requires what 3 pos tests?

A

Good strong beta hemolysis
Stab O pos
Bacitracin sus (no growth )

33
Q

Define SXT and when it is used.

A

Inhibits NF sulfamethaxazole and trimethroprim

34
Q

Explain in detail how an ELISA Rapid Strep Test Kit functions.

A

Sample with C carbo added- antibody and enzyme conjunction added- add substrate = reaction of color is pos on T line

35
Q

List and describe the 6 pathogenic factors of Gp. A Strep. Streptococcus 6

A

-M protein: resists phagocytosis and adhere to mucosal cells
-Dnase: break down DNA to give more room
-Hyaluronidase: breaks down connective tissue- spreading factor
-Streptokinase: breaks up clots
-Streptolysin O and S: breaks down RBC’s
-Pyrogenic exotoxins

36
Q

List and describe the clinical diseases each of the major Streptococcus species and Enterococcus. List the antimicrobial therapy or vaccines (if available) used to treat each species.

A
  1. Localized infections:
    -pharyngitis- 90% Gp A strep ages 5-15
    -impetigo- pustule
    -erysipelas- clear demarcations
    -cellulitis deeper invasion
  2. Sequelae:
    -Scarlet fever-rash
    -Rheumatic fever- inflammation of heart
    -Acute glomerulonephritis- hypertension and low urine output
    -Invasive Group A strep- necrotizing fasciitis
    -Toxin shock syndrome- spread to blood
37
Q
A

MLS503 (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions