Lecture 3 highlights: Bacteria

Question 1

1) Pyrogens act on body’s thermostat in the ______________, raising body temperature
2) Name 3 medications that can induce fever

Answer 1

1) hypothalamus
2) Beta-lactams, nitrofurantoin, sulfonamides

Question 2

Most infections result in elevated levels of what?

Answer 2

WBCs (leukocytosis)

Question 3

1) What make up 70% of WBCs?
2) Basophils are involved in what?
3) What are eosinophils involved in?

Answer 3

1) Neutrophils
2) Allergic rxn
3) Parasitic rxns and allergic rxns

Question 4

What WBC would be elevated with viral illnesses or unusual bacterial infections?

Answer 4

Basophils

Question 5

What are cytokines?

Answer 5

Messengers

Question 6

1) What does an antibiogram tell you?
2) What does “formulary” mean when considering which empiric therapy to choose?

Answer 6

1) Rates
2) What medications are likely in stock

Question 7

True or false: A component of antimicrobial stewardship is switching from IV to PO antibiotics in a timely manner

Answer 7

True

Question 8

Who sets the susceptibility breakpoint?

Answer 8

Clinical & Laboratory Standards Institute (CLSI)

Question 9

1) How many sets of blood cultures should you order?
2) What do you need to tell pts about collecting urine for a culture?

Answer 9

1) 2 or more
2) Midstream catch

Question 10

What are the 3 results of gram staining?

Answer 10

Positive, negative, and atypical

Question 11

Bacteria:
1) What are rods?
2) What are spheres?

Answer 11

1) Bacilli
2) Cocci

Question 12

1) What are the two shapes of gram positive bacteria?
2) What are the two types of G+ cocci?

Answer 12

1) Cocci and bacilli
2) Catalase positive (staphylococcus) and negative (streptococcus)

Question 13

1) What are the two types of catalase positive (G+) cocci?
2) What are the 3 main types of G- bacteria?

Answer 13

1) Coagulase + (S.a) or coagulase -
2) Cocci, bacilli, and coccobacilli

Question 14

What are the 3 main types of streptococcus?

Answer 14

1) Beta-hemolytic (clear)
2) y-hemolytic (enterococcus)
3) alpha-hemolytic (green)

Question 15

1) Name some infections caused by S. aureus (a species of staphylococci)
2) What type is either nosocomial or community acquired, and is treated with vancomycin? What does it produce?

Answer 15

1) Skin/ soft tissue infections, TTS
2) Methicillin-resistant staphylococcus aureus (MRSA). PBP2’ .

Question 16

Name a strain of staph. aureus besides Methicillin-resistant staphylococcus aureus (MRSA)

Answer 16

Vancomycin-resistant staphylococcus aureus (VRSA)
-alter peptide chain structure of peptidoglycan subunit

Question 17

1) Is staphylococcus epidermidis more or less virulent than S. aureus?
2) What type of infections does it usually result from?
3) What are most strains resistant to?

Answer 17

1) Less virulent
2) Foreign objects (catheters, prosthetic joints, etc)
3) Methicillin resistant (MRSE)

Question 18

Name a type of diplococcus that’s α-hemolytic and commonly causes pneumonia and meningitis

Answer 18

Pneumococci (S. pneumoniae)

Question 19

Viridans group streptococci:
1) What hemolysis pattern?
2) Name one of the places it commonly colonizes
3) Name 3 infections it causes
4) Is it very virulent?

Answer 19

α-hemolytic (incomplete hemolysis)
2) Mouth
3) Infective endocarditis, dental caries, and neutropenic pt infections
4) No; low virulence

Question 20

1) Group A (S. pyogenes) strep does what kind of hemolysis?
2) Name a condition it often causes
3) It has immune-mediated post-infection sequelae; what does this mean?

Answer 20

1) Beta
2) Pharyngitis
3) It can come back if full course of antibiotics not taken; can come back as Rheumatic fever or acute glomerulonephritis

Question 21

Group B (S. agalactiae) strep:
1) What type of hemolysis?
2) Who is most commonly infected?

Answer 21

1) Beta-hemolysis (complete)
2) Neonates and infants

Question 22

1) Enterococci were formerly known as what?
2) What are two types? Which is more common? Which is more resistant?
3) What are they normal flora of?

Answer 22

1) Streptococcus
2) E.faecalis is more common, E. faecium has more resistance
3) GI tract

Question 23

1) Name 2 infections Enterococci can cause.
2) Why are they intrinsically resistant to so many drugs?
3) Name an antibiotics they’re resistant to

Answer 23

1) UTIs, endocarditis
2) Almost all drugs are bacteriostatic
3) Vancomycin resistant enterococci (VRE)

Question 24

1) Name 2 species of coccobacilli
2) What are all gram negative cocci? Give 2 examples.
3) Klebsiella, E. coli, and Enterobacter are all examples of what?

Answer 24

1) H. influenzae and L. pneumophila
2) Neisseria spp; N. meningiditis and N. gonorrhoeae
3) Lactose + bacilli that are fast fermenters

Question 25

What are the 3 types of lactose negative G- organisms? Give examples of 2 of the types

Answer 25

1) Oxidase + (P. aeruginosa)
2) Oxidase-
3) Strict anaerobes (B. fragilis)

Question 26

P. mirabilis is an example of what?

Answer 26

A urase +, oxidase -, G- bacteria

Question 27

Enterobacteriaceae (G-):
1) Give 3 examples in this category
2) Why do these 3 examples have resistance? To what?

Answer 27

1) E. coli, Proteus, Klebsiella
2) Extended-spectrum beta-lactamase (ESBL):
Degrade all beta-lactams except carbapenems and sometimes β-lactam/β-lactamase inhibitors

Question 28

1) Klebsiella often causes infections in pts with what?
2) What gives it resistance, and to what?
3) What bacteria almost exclusively cause UTIs?

Answer 28

1) Alcoholism
2) Cabapenemase (KPC); to all beta-lactams
3) Proteus

Question 29

Serratia, Citrobacter, Enterobacter, Morganella are all more examples of what? What’s the mnemonic to remember this category?

Answer 29

Enterobacteriaceae; SPACE-M

Question 30

1) Serratia, Citrobacter, Enterobacter, Morganella all have what resistance mechanism?
2) What 3 things does this give them resistance to?

Answer 30

1) AmpC-type β-lactamase
2) PCN, ampicillin/amoxicillin, 1st generation cephalosporins

Question 31

Give 2 examples of non-fermenters

Answer 31

Acinetobacter baumanii and Stenotrophomonas maltophilia

Question 32

Stenotrophomonas maltophilia: community or nosocomial? Does it have resistance?

Answer 32

Nosocomial pathogen with intrinsic resistance

Question 33

What bacteria has many virulence factors that contribute to tissue damage and help with motility and adherence?

Answer 33

P. aeruginosa

Question 34

1) P. aeruginosa is a frequent cause of what kind of infections?
2) What increases the risk of these?

Answer 34

1) Nosocomial infections
2) Loss of anatomical/physiological barrier, recent antibiotic

Question 35

What is are the two main groups of Haemophilus influenzae

Answer 35

Typable and non-typable

Question 36

1) What is Haemophilus influenzae type B?
2) Is there a vaccine? If so, does it work? If not, why?
3) What kind of infection is caused by non-typable Haemophilus influenzae?

Answer 36

1) Type b: invasive infections
2) HIB vaccine: highly effective
<1% colonization in vaccinated patients
3) Mucosal infections (mild)

Question 37

1) Neisseria meningitidis usually causes meningitis and sepsis in what 3 groups?
2) How is Neisseria gonorrhoeae spread?

Answer 37

1) Young children, college freshman, and military recruits
2) Sexually transmitted disease

Question 38

1) What are the two main types of chlamydia? List each species.
2) Why can it be described as “sneaky”?
3) What type of bacteria is it?

Answer 38

1) STD (C. trachomatis) OR pneumonia and bronchitis (C. pneumoniae)
2) Obligate intracellular organism
3) Atypical [gram stain]

Question 39

1) What atypical organism lacks a cell wall?
2) What does Legionella inhabit and what can it cause?

Answer 39

1) Mycoplasma
2) Waterways; Legionnaires’ disease

Question 40

1) Is Clostridium G+ or -? How else can it be identified?
2) Name 4 things it can cause
3) Why is it unique?

Answer 40

1) Gram-positive, spore-forming
2) Tetanus, botulism, gangrene, C.diff
3) Very few anaerobic bacteria cause infections

Question 41

What non-spore forming anerobic bacteria rarely causes infections alone? What’s it’s shape?

Answer 41

Peptostreptococcus; cocci

Question 42

1) What class of G- bacteria is anerobic? What species does this include?
2) Name 2 characteristics of this species

Answer 42

1) Bacteroides, B. fragilis
2) More virulence factors; Beta-lactamase production