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Flashcards in Introduction to Infectious Disease Deck (79):
1

Host flora

Occupy space and compete for nutrients
Stimulate cross-protective antibodies
Suppress growth of potentially pathogenic bacteria and fungi

2

Can normal flora become pathogenic

Yes

3

Colonization vs Infection

Colonization- organism present
Infection- organism present, organ damage, and inflammation.
Autoimmune disease- organ damage and inflammation

4

Monitoring Parameters

Fever- >37 C (98.6 F) in adults
Erythema- redness of the skin
Purulence- discharge of pus
Swelling
Leukocytosis- elevated WBC

5

WBC- Leukocytes

1% of blood volume
Carry out immune system functions and recognize self from non-self.
Average life span 13-20 days

6

Differential WBCs

Neutrophils- 50-70%
Lymphocytes 25-35%
Monocytes- 2-6%
Eosinophils- 0-6%
BBasophils- 0-3%

7

Granlocytes

Neutrophils, eosinophils, and basophils

8

Neutrophils mechanism

Prevent microorganism invasion, kill invading organisms
Attracted to site of infection by chemotactic factors. Then Phagocytize the microorganisms. Release toxic substances from granules within cell into vacuole containing organism.

9

Neutrophils

Contain multi-lobed nuclie (segs)
Production stimulated by interleukins and other colony stimulating factors (CSF)
Increased bands in circulation causing left shift

10

Segs

Term used to describe a mature working neutrophil, if found then you know they are actively trying to prevent infection

11

Bands

Immature neutrophil, increased means that more immature cells are being pushed out of the marrow (eukemia)

12

Absolute Neutrophil Count (ANC)

The lower the value the higher the risk of infection
WBC # x (%segs+%bands)

13

Neutropenia

Not enough neutrophils
Mild= ANC 1000-1500/mm3
Moderate= ANC 500-1000mm3
Severe= ANC <500mm3
This gives an idea of how a pt can handle an infection process on their own.

14

Lymphocytes

Effector cells of immune system, recognize invaders, tag them for removal and kill them.
Make antibodies- Tcells 80% and B cells 20%

15

WBC-Monocytes

Serve to replenish tissue with macrophages prior to and during immune response

16

WBC- Eosinophils

Responsible for immuner processes against helminths and parasites (also involved in allergic rxn)

17

WBC- Basophils

Mediate inflammatory response

18

Gram stain- Gram (+) Cocci

chains- streptococcus pyrogens, viridans streptococcus
Pairs- streptococcus pneumoniae and enterococcus spp.
Clusters- coagulase-positive staphylococcus (S. aureus) Coagulase -negative Staphylococcus (S. epidermis)

19

Gram stain- Gram (+) Bacilli

Listeria and lactobacillus

20

Gram stain- Gram (-) Cocci

Neisseria menigitidis and Neisseria gonorrhoeae

21

Gram stain- Gram (-) Bacilli

Escherichia Coli
Klebsiella Spp
Enterobacter spp
Proteus spp
serratia marcescens
Pseudomonas spp

22

Gram stain- Gram (-) Coccobaccili

Haemophilus influenzae

23

Cell wall- Gram Positive

Rigid, thick
Made up of mostly peptidoglycan (50-60%)
A series of cross-linking (transpeptidases) help to create the building blocks of the cell wall

24

Cell wall- Gram Negative

Cell wall thin layer-one or two glycan chains
Cell wall protected by lipoprotein outerlayer- which functions as a penetration barrier.
Lipopolysaccharide (LPS)
Matrix protein (porin)- important for regulating the influx of molecules
Phospholipids

25

Cell walls- Walls of mycobacteria (Acid fast bacteria)

Contains peptidoglycan w/ polysaccharide and glycolipids
Associated with staining characteristics

26

Cell Walls- Cytoplasmic membrane

Osmotic barrier
Energy production (electron transport-energy grandient- ATPases)
Biosynthesis transport (nutrient uptake, enzyme secretion)
Protein and lipid- lacks sterols

27

Antimicrobial Susceptibility- MIC

Minimun inhibitory concentration (MIC) lowest concentration of antibiotic that inhibits visible growth of bacteria. Want to shoot for 2-4x above this in treatment.

28

Antimicrobial Susceptibility- Breakpoints

Susceptible- isolates may be appropriately treated with the recommended doses
Intermediate- isolates may be appropriately treated in body sites where the drug is physiologically concentrated or when a high dosage of a drug can be used
Resistant- isolates are not inhibited by the achievable concentrations of a normal dose

29

Gram Positive cocci (Aerobic)- Staphylococcus

Staphylococcus aureus (Coag+)- MSSA, hospital or community acquired MRSA.
Staphylococcus epidemidis(Coag -)
Staphylococcus saprophyticus (Coag -)

30

Gram Positive cocci (Aerobic)- Enterococcus

Enterococcus Faecalis
Enterococcus faecium
Enterococcus durans

31

Gram Positive cocci (Aerobic)- B hemolytic

Streptococcus pyogenes (Grp A)
Streptococcus agalactiae (Group B)
Streptococcus bovis (nonenterococci, grp D)

32

Gram Positive cocci (Aerobic)- Viridans streptococci- alpha hemolytic

Streptococcus sanguis
Streptococcus salivarius
Streptococcus mitis
Streptococcus mutans

33

Gram Positive cocci (Aerobic)- Streptococcus pneumoniae

Pneumococcus

34

Staphylococci- colinzation

Skin and nose

35

Staphylococci- Infections caused

Cellulitis, wounds, trauma
Bacteremia/endocarditis
Pneumonia
Osteomyelitis
UTI

36

Staphylococci- post surgery

Major players in post surgical infections.
Adhere to foreign material and catheters

37

Staphylococcal Resistance

Penicillin resistant- beta-lactamase production
Methicillin resistant- MecA gene codes for Novel PBP2a (50% S. aureus and 70% CoNS are resistant)
Methicilin-suspectible isolates are also susceptible to cephalosporins and carbapenems.

38

Streptococcus- Colinzation

Skin- grou A- S. pyogenes
Mouth- viridans streptococcus, anaerobes (e.g. peptostreptococcuss)
Nasopharynx- group A S. pyogenes
Lower GI- group D- S. bovis, viridans streptococcus and anaerobes
Female Genital tract- Group B- Agalactiae

39

Streptococcus- infections caused- cellulitis

Group A- S. pyogenes may result in Nec fascitis

40

Streptococcus- infections caused- Dental carries

Viridans Streptococcus

41

Streptococcus- infections caused- pharyngitis (Strep throat)

Group A- S. Pyogenes

42

Streptococcus- infections caused- bacteremia/endocarditis

Viridans Streptococcus

43

Streptococcus- infections caused- neonatal meningitis

Group B- S. Agalactiae

44

Streptococcus treatement

Penicillin
More resistance seen with alpha-hemolytic strep, specifically S. Mitis

45

Pneumococci

Alpha hemolytic

46

Pneumococci- colonization

Oropharynx and nasopharynx

47

Pneumococci- infections caused

Otitis media, sinusitis, bronchitis, Pneumoni (CAP Community required pneumonia), and meningitis

48

Pneumococci- Asplenia

Without the spleen patients are at risk for fulminant sepsis syndrome.
Lack filtration mechanism of spleen macrophages
Cannot clear encapsulated organisms- S. pneumoniae, H. influenzae, and N. menigitidis

49

Pneumococci- treatment

Penicillin resistant strains due to PBP alterations
3rd generation cephalosporins (ceftriaxone)
May de-escalate with cultures and sensitivities

50

Enterococci- colonization

Gastrointestinal tract and female genital tract
Resistance is the best defence

51

Enterococci- infection

Opportunistic
UTI
Bacteremia/Endocarditis
Intra-abdominal infections

52

Gram Negative (aerobic)

Rods- Enterobacter spp, escherichia coli, klebsiella pneumoniae, proteus vulgaris, proteus mirabilis, serratia marcenena, pseudonomas aeruginosa, cocc/coccobaccilli

53

Enterobacteraciae

GI tract colonization
Exposure comes from soil, water, vegetation
LPS cell wall component and endotoxin.

54

Enterobacteraciae- infections

UTI
Intra-abdominal infections
Bacteremia
Nosocomial pneumonia
Diabetic foot infections

55

Enterobacteraciae- resistance

Prevalent
More common in hospital-acquired infections
Tx guided by in vitro susceptibility

56

Pseudomonas aeruginosa

Not considered normal flora (sold, water, vegetation)
Can colonize upper respiratory tract of immunocompromised patients- cystic fibrosis, COPD
Opportunistic- immunocompromised pt, broad spectrum ABX, ventilation equiptment

57

Pseudomonas- infections

Nosocomial infections
Hospital acquired pneumonia (HAP)
Febrile neutropenia
Skin and soft tissue infections (burns, trauma, post-surgical)
UTI

58

SPACE Organisms- double covering

Double covering- Tx w/ 2 ABX
Serratia
Psuedomonas
Acinetobacter
Citrobacter
Enterobacter
More adverse effects, no more resistance

59

Gram (-) Cocci/Coccobacilli- Haemophilus Influenzae

Encapsulated- more virulent, not regular colonizer, causes meningitis
No capsule- Colonizes upper respiratory tract, causes otitis media, sinusitis, CAP

60

Gram (-) Cocci/Coccobacilli- Neisseria Menigitidis

Humans only nature host
Colonizes oro/nasopharynx
Encapsulated
Causes meningitis and less commonly pneumonia

61

Polysaccharide capsule (PS)

Eludes immune system
Requires speen for elimination
PS capsule is target for vaccines- Hib vaccine and meningococcal vaccine

62

Anaerobes- above diaphragm

Petpstreptococcus spp (gram + cocci)
Actinomyces spp (gram + rod)
Fusobacterium (gram - rod)

63

Anaerobes- below diaphragm

Bacteroides fragilis (gram - rod)
Lactobacillus (gram + rod)
Clostridium spp (gram + rod)

64

Gram negative isolates

Usually penicillinase prodcuers

65

Anaerobes- colinization

Upper and lower Gi and vagnial colonizers.

66

Anaerobes- infection

Intra-abdominal infection, aspiration pneumonia, endometritis, PID, diabetic lower extremity infections, dental carries, head and neck.

67

Atypicals

Not normal colonizers
Not able to gram stain
Mutiply intracellularly
Result in CAP

68

Atypicals- organisms

Mycoplasma pneumonia
Legionella pneumophilia
Chlamydophila pneumoniae

69

Atypicals

Even Some Super Killers Have Pretty Nice Capsules
Escherichia Coli
Streptococcus Pneumoniae
Salmonella
Klebsiella pneumoniae
Haemophilus influenzae
Pseudomonas geruginosa
Neisseria meningitidis
Cryptococcuss neofromans (yeast)

70

9 classes of bacterial pathogens- Streptococci

Group A strep, viridans strep

71

9 classes of bacterial pathogens- Streptococcus pneumoniae

Streptococcuss pneumoniae

72

9 classes of bacterial pathogens- Enterococcuss

usually faecalis

73

9 classes of bacterial pathogens- Staphylococci

S. aureus, coagulase-negative

74

9 classes of bacterial pathogens- atypical bacteria

Mycoplasma, chlamydia, legionella

75

9 classes of bacterial pathogens- Haemophilus influenzae

haemophilus influenzae

76

9 classes of bacterial pathogens- Gram negative rods

E. coli, Klebsiella, Proteus, ect

77

9 classes of bacterial pathogens- Pseudomonas aeruginosa

Psuedomonas aeruginosa

78

9 classes of bacterial pathogens- Anaerobes

Bacteriodes, clostridia, pervotella

79

Nine Important "Classes" of Bacterial Pathogens

Streptococci
Streptococcus Pneumoniae
Enterococcus
Staphylococci
Atypical bacteria
Haemophilus Influenzae
Gram negative rods
Peudomonas Aeruginosa
Anaerobes