Introduction to Bacteriology I Flashcards Preview

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Flashcards in Introduction to Bacteriology I Deck (22):
1

What accounts for the purple staining of gram + organisms relative to gram -?

1. cell wall peptidoglycan layer is thicker in gram +--> teichoic acid cross-linkages--> resists alcohol decolourization step

2. magnesium ribonucleate in gram + cell wall--> affinity for crystal-violet-iodine complex

3. gram + cell wall less permeable bc less lipid

2

What are the uses of the gram stain for microbes?

1. basis for empiric antibiotic therapy

2. identifying non-bacterial microbes (ex. fungi..yeast)

3. assessing specimen adequacy (may be contaminated with normal flora/cells)

3

Describe Staphylococcus spp. in terms of : Gram stain, shape, respiration, pattern

-GP
-cocci
-Aerobic
-clusters

4

What are the 2 major groups of important Staphylococcus species and examples of each

1. S. aureus:
-MRSA

2. Coagulase-negative staphylococci:
-S. epidermitidis
-S. lugdunensis
-S. saprophyticus

5

Describe Streptococcus spp.:

What does it look most like?

-GP
-cocci
-aerobic
-chains

*looks like enterococcus

6

List 2 major groups of Streptococcus spp. and examples of each:

1. Beta-hemolytic streptococci-red/orange halo:
-S. pyogenes (Group A Strep) **short chains
-S. agalactiae (Group B Strep)


2. Alpha-hemolytic streptococci- green halo:
-S. pneumoniae **diplococci, lancet-shape
-Viridans group strep **long chains

7

Describe Enterococcus spp.:

-GP
-Cocci
-chains
-aerobic

8

List important Enterococcus spp.:

-E faecium
-E faecalis
-Vancomycin-resistant E. faecium (VRE)
-Vancomycin-resistant E. faecalis (VRE)

9

What 2 GP bacilli do we need to know? (both are aerobic)

-Corynebacterium spp.
-Bacillus spp.

10

What do Corynebacterium look like (describe):

-GP
-Bacilli
-shaped like letters/palisades
-aerobic

11

What are important Corynebacterium spp?

-C. jeikeium
-C. urealyticum
-C. diphtheriae (uncommon)
-'diphtheroids'

12

Describe Bacillus spp.:

-GP
-Bacillus
-singular
-aerobic

13

List important Bacillus spp. :

-B. anthracis (uncommon)
-other species part of normal skin flora

14

Describe Escherichia coli

-GN
-Bacillus
-singular
-aerobic

15

List important enterobacteriaceae (enteric GNs)

-Escherichia coli
-Klebsiella pneumoniae
-Enterobacter spp.
-Citrobacter spp.
-Proteus spp.
-Salmonella spp.
-Shigella spp.

16

Describe Haemophilus spp.:

-GN
-coccobacilli
-singular
-aerobic

17

List the one important Haemophilus spp.:

-H. influenzae

18

Describe Neisseria spp.:

-GN
-Cocci
-Diplococci
-aerobic

*coffee bean shaped

19

List the important Neisseria spp.:

-Neisseria meningitidis
-Neisseria gonorrhoeae
-non-pathogenic Neisseria spp.

20

Describe Clostridium spp. :

-GP
-Bacilli
-pairs
-anaerobic

21

List the important Clostridium spp.:

-C. tetani
-C. botulinum
-C. perfringens
-C. difficile

22

Describe Becteroides spp.:

-GN
-Bacilli
-clusters
-anaerobic (strict i.e. die in O2)