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Phase 2a > Microbiology > Flashcards

Flashcards in Microbiology Deck (260)
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31

Treatment of COPD infection?

amoxicillin with clavulanate, tetracycline, trimethoprim

32

Likely organisms to cause pneumonia?

pneumococus

33

Treatment of pneumonia?

B lactams, erythromycin

34

Likely organisms in a wound?

staph aureus, strep pyogenes, anaerobes

35

Treatment of a wound?

flucloxacillin, erythromycin, co-amoxiclav

36

How can antibiotics be misused?

use broad spectrum when narrow are just as effective, treat for too long, treating with IV when oral is as effective, using combination when one is a effective, failure to use a dose appropriate for renal and hepatic function, using antibiotics for highly unlikely organisms, failure to step down organism once known

37

Dangers of antibiotic misuse?

adverse drug reactions which increases with multiple drug prescribing, harmful drug interactions, errors in prescribing monitoring, can cause super infection and antibiotic resistance

38

What is the difference between bacteriostatic and bactericidal?

bacteriostatic - prevents bacteria growth by inhibiting protein synthesis, DNA replication or metabolism, reduces toxin production

bactericidal - kills bacteria by inhibiting cell wall synthesis, good if poor penetration

39

Why do antimicrobials want a large MIC?

minimum inhibitory conc - to attach to more binding sites to inhibit bacteria

40

What factors must be considered in drug administration choice?

will it penetrate, pH of the site, is antimicrobial lipid soluble

41

How do bacteria resist antimicrobials?

change antimicrobial site by changing binding site configuration, destroy or inactivate the antimicrobal, prevent antimicrobial etery by modifying bacterial membrane porin channel site, numbers or selectivity, remove antimicrobial from bacterium using export pumps

42

How does bacterial resistance develop?

intrinsically naturally resistant so subpopulations can develop it too

acquired - not all subpopulations are equally resistant

43

Gram positive antimicrobial resistant bacteria?

MRSA, VRE

44

Gram negative antimicrobial resistant bacteria?

B lactamases, ESBL, carbapenenases, AmpC B lactamase resistant

45

What methods can be used to test antimicrobial resistance?

antimicrobial sensitivity testing, chromogenic plates, mechanism specific tests, genotypic methods, breakpoint plates

46

What is a pathogen?

an organism that is capable of causing disease

47

What is a commensal?

an organism which colonises the host but causes disease in normal circumsatnces

48

What is an opportunist pathogen?

only causes disease if host defences are compromiseed

49

What is pathogenicity?

the degree to which an organism is pathogenic

50

What is asymptomatic carnage?

when a pathogen is carried harmlessly at a tissue site where it causes no disease

51

Components to a bacteria?

capsule, cell wall, outer and inner membrane, pili, chromosome, may also have plasmids

52

What is the function of a capsule on bacteria?

super coated so difficult for phagocytes to ingest

53

What is used to stain acid fast bacilli?

Ziehl Neelsen stain

54

What colour is a gram positive stain?

purple/blue

55

What colour is a gram negative stain?

pink

56

What is the difference in gram positive and negative cell wall composition?

n = more lipopolysaccharide, with lipoprotein, less peptidoglycan with inner and out membrane

p = more peptidoglucan with lipoteichoic acid and cytoplasmic membrane

57

What is the idea bacterial environment?

temperature

58

What are the 4 stages of bacterial life?

lag, exponential (log), stationary, death

59

What is endotoxin?

component of outer membrane of bacteria produced by lipopolysaccharide gram negative, has non specific action, stable effect of heat, weak antigenicity and not convertable to toxoid

60

What is exotoxin?

secreted by gram positive (and negative), can be converted to toxoid, strong antigenicity, liable effect of heat and specific action