Brainscape's Knowledge GenomeTM

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


See full index

Infectous Disease > Dr. Cluck > Flashcards

Dr. Cluck Flashcards

1
Q

What is an infection?

A

A microorganism that is able to replicate invades host tissue and causes an immune response (disease)

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

Example of an infection

A

A gram-negative bacteria in a septic environment of the body –> in the blood stream

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

What is a Contaminant?

A

On the outside

Organism as a normal part of the skin flora, isolated from the bloodstream

-but there could be some bacteria as Contaminants in the bloodstream

-Almost never requires treatment

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

What is a Colonization?

A

An organism that is endemic to a specific part of the body

-MRSA colonization after being in the hospital
-Usually doesn’t require treatment

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

What are Gram-resistant Organisms?

A

-They need special forms of staining or cant be stained (lack of cell wall)

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

Why do Gram-resistants need special staining or cant be stained?

A

-Mycobacteria and Nocardia have a wax-like outer layer -> cant take up the stain -> acid-fast

-Treponema requires fluorescent AB staining
-Intracellular pathogens - cant be stained
-Mycoplasma lacks cell wall - cant be stained

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

What is an atypical organism?
EXAM

A

-Gram-resistant

-Neither Gram-positive nor Gram-negative

-bacteria that do not get colored by gram-staining but rather remain colorless

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

What are the most common morphological forms of bacteria?

A

-Rod-shaped: E. coli
-Cocci in chains: Streptococcus spp.
-Grapelike cluster: Staphylococcus spp.

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

How are Cocci-shaped gram (+) bacteria specified?

A

with Catalase
Clusters: Staphylococcus spp.

w/o Catalase
Pairs/chains: Streptococcus spp.

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

How is Staphylococcus specified?

A

(+) Coagulase: S. aureus -> causes disease

(-) Coagulase: S. epidermidis, S. saprophyticus

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

How is Streptococcus specified?

A

-alpha hemolysis: partial, green
-beta hemolysis: complete, clear
-gamma hemolysis: no hemolysis

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

How are rods specified:

A

Aerobic and Anaerobic

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

Assays to identify Gram (+):

A

Gram staining (cluster VS strips)
Biochemical: Catalase, Coagulase
Lancefield antigens (carbohydrate side chain)
Hemolytic reaction on blood agar

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

Why should Staph aureus NEVER be considered Contaminant?

A

-most virulent gram-positive pathogen
-can cause multiple diseases: bacteremia, skin tissue infections, endocarditis, pneumonia, foodborne, toxic shock

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

Characteristics of Staph. aureus

A

-produces ß-lactamases
-Catalase and Coagulase positive (only coagulase pos. staph.)
-Methicilin-resistance through mecA gene (PBP2a protein)

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

Function of Catalase

Function of Coagulase

A

Catalase: reduces phagocytic killing

Coagulase: facilitates abscess formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does Penicillin work?

A

-It inhibits the Transpeptidase in the cell wall of bacteria

-mecA creates PBP2a -> the cell wall is able to continue its replication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the therapeutical approach to Staph aureus?

A

Vancomycin
If Severe -> IV therapy
If MSSA -> antistaphylococcal penicillin C D M N O (penicillinase-resistant penicillin) or 1st gen cephalosporin
PO: dicloxacillin, cephalexin (1st gen cephalosporin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why do penicillinase-resistant penicillins work against bacteria with ß-lactamase?

A

Because of the bulky sidechain (steric hindrance), bacterias ß-lactamase cant access the ß-lactam ring and hydrolyze it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which antibiotic doesn’t work for MSSA?

A

Vancomycin ????
-studies show poor outcome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

EXAM Question: Know which antibiotics are IV and which are PO

A

If severe -> IV: Nafcillin

Cephalexin (PO) would be the best choice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are therapeutic options to treat MRSA?

A

If invasive (f.e. Pneumonia), not superficial -> Vancomycin

If superficial -> PO: doxycyclin, clindamycin, TMP-SMX

Alternatives: linezolid, daptomycin, tigecycline, ceftaroline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the difference between Staph aureus and epidermidis

A

Staph epidermidis is Coagulase negative

often considered contaminant, but still cause disease -> often on prosthetic devices (pacemakers) -> because they are sticky and build biofilms

24
Q

How to treat Staph epidermidis?

A

If there is an infection Vancomycin is necessary
due to mecA and methicillin-resistance

25
Q

How are staph. saprophyticus different from other spp?

A

-dont produce ß-lactamase -> can be treated with ß-lactams, TMP-SMX or fluoroquinolone

-mostly cause UTI in young sexually active females

26
Q

What are Lancefield Antigens?

A

-antigenic differences in cell wall carbohydrates of Streptococcus spp.

-Gr. A, B, D
Possible Examq: Which Strep doesn’t have Lancefield Antigen -> Streptococcus pneumoniae?

27
Q

Hemolytic reactions

A

Alpha: partial, green
Beta: complete, clear
Gamma: no hemolysis

28
Q

What else makes Streptococcus spp. different from Staphylococcus?

A

-they DO NOT produce b-lactamase
-> Amoxicillin/Clavulanate (Augmentin) won’t work ???(adverse effect: diarrhea)
-> use Penicillin

29
Q

How to treat Streptococcus pyogenes?

A

Penicillin; if PCN allergic -> Clindamycin or TMP-SMX

30
Q

Streptococcus agalactiae - Group B strep

A

-often found with wound infections in diabetics, obese patients

-neonatal infection (meningitis) - colonizer of the vagina –> take Penicillin to decolonize

-normal inhabitant of the GI

31
Q

What is the susceptibility of Group A and B strep to Penicillin?

A

100%
any ß-lactam can be used (one exception)

32
Q

What is S. gallolyticus (bovis) known for?

A

-Group D Strep –> treat with Penicillin
-Normal inhabitant of the GI
-when found in the blood -> marker for colonic neoplasia
-can cause endocarditis

33
Q

What does Streptococcus pneumoniae cause?

A

-Triad of endocarditis, meningitis, and pneumonia
-30% PCN resistance -> different ß-lactam or FQ (fluoroquinolone)

34
Q

Viridans streptococci

+ Streptococcus anginosus

A

-part of the normal GI flora (including oral
cavity)
-endocarditis secondary to poor dentition or damaged heart valves
-Penicillin, resistance is rising

35
Q

What is Enterococcus known for?

A

-normal bowel flora

-not very pathogenic (BYSTANDER analogy), unless it is found where it is not supposed to be (blood)

-very resistant

-can cause wound infections, endocarditis, UTI

36
Q

Name two important Enterococci

A

-E. faecalis - responds better to drugs
-E. faecium is more drug resistant

37
Q

How to treat Enterococcus?

A

-Use two drugs - the concept of drug SYNERGY (2 different MOAs)
-one ß-lactam is just bacteriostatic

-1st line for E. faecalis line is Amino penicillins plus an aminoglycoside
-for E. faecium (more resistant) -> Vancomycin

-Alternative: Linezolid, daptomycin

38
Q

Diseases caused by Mycobacteria

A

-wide range of diseases - Tuberculosis, leprosy

39
Q

Identification and treatment of Mycobacteria

A

-lipid-rich cell wall -> acid-fast
-differentiated by the rate of growth

tuberculosis requires 4 drug therapy (1 year or longer)
-Non-tuberculosis mycobacteria -> most are resistant: M. abscessus, M. fortuitum, M. marinum

40
Q

Disease caused by Bacillus anthracis

A

Anthrax
-B. cereus in reheated rice

-antibiotics is not necessary

41
Q

Listeria monocytogenes

A

-can cause meningitis, but often mild
-food-borne illness

-treat with ampicillin or TMP-SMX or Vancomycin
-Neprosporin wont work!

42
Q

Diseases caused by Clostridium

A

-C. perfringens can cause food-borne illness as well as gas gangrene
-C. difficile is responsible for pseudomembranous colitis
-C. tetani and C. botulinum cause different types of paralysis

43
Q

How to treat Clostridium

A

-Almost all Clostridia spp. are penicillin-susceptible

-C. difficile - oral Vancomycin; in severe case add IV metronidazole

44
Q

What is the only organism that is treated with oral Vancomycin?

A

Clostridium difficile

45
Q

Bacteria causing infection the upper respiratory tract

A

-Moraxella catarrhalis -> CA-pneumonia, otitis
media, and sinusitis

-Haemophilus influenzae (type B capsule) - vaccine available

46
Q

Acinetobacter sbb.

A

-Very resistant pathogen (hospital outbreaks)
-VAP and wound infections
-sulbactam has microbiologic activity (ß-lactam inhibitor usually don’t have activity)

47
Q

Neisseria

A
  • N. meningitidis is responsible for meningitis
    -> 3rd generation cephalosporin/Pen G
  • N. gonorrhoeae is responsible for gonorrhea, septic arthritis, and PID
    -> cephalosporins

Alternative: FQ, macrolides

48
Q

What are Enterics?

A

-Enterobacterales (big class)

-commonly seen in hospital-acquired syndromes and immunocompromised patients

-Salmonella and Shigella are NOT part of normal flora

49
Q

What are the Resistance Patterns Associated with
Enterobacterales?

A

-E.coli and Klebsiella can produce extended spectrum β-lactamases (ESBLs)

AmpC-ß-lactamase hydrolyze many ß-lactams

-use carbapeneme to treat

50
Q

Pseudomonas aeruginosa

A

-significant in hospital-acquired infections
-often multidrug-resistant

51
Q

Characteristics of Anaerobes

A

-a harmless commensal relationship with the host
-Trauma and host factors can cause infection
-treat -> agents with activity against anaerobes (eg
metronidazole, clindamycin, carbapenems)

52
Q

Use of carbapenems:

A

-against anaerobes
-Enterobacterels with resistance pattern -> E. coli and Klebsiella

53
Q

Rocky Mountain Spotted Fever

A

Rickettsia rickettsii
-gram-negative intracellular coccobacillus
-transmission via arthropods (ticks)

-treat with Doxycycline 100 mg BID
in pregnancy chloramphenicol

54
Q

Lyme Disease

A

-Borrelia burgdorferi (intracellular)
-Transmission also occurs via an arthropod vector – ticks
-Treatment is doxycycline or a β-lactam (usually ß-lactams don’t work for intracellular pathogens)

55
Q

Chlamydophila vs.Chlamydia

A

-Chlamydophila pneumoniae: atypical pneumonia -> Community acquired -> Doxycyline

-Chlamydia trachomatis: STD -> Doxycycline

-need high intracellular concentrations such as macrolides or tetracyclines

Infectous Disease (29 decks)

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