Antimicrobials Principles Part 1

Front 1

Goals of antimicrobial therapy

Back 1

Resolution of infection, avoidance of resistance

Front 2

Evidence of resolution of infection

Back 2

Resolution of clinical signs

Front 3

This use of drugs in food animals has contributed to resistant microbes in foods

Back 3

Antimicrobials as growth promotants

Front 4

Example organisms for which resistance has developed in food animals

Back 4

Campylobacter, Salmonella

Front 5

True or False: Bacteria move FROM humans TO animals

Back 5

TRUE

Front 6

The term used to refer to transfer of microorganisms from animals to humans and from humans to animals, respectively

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Zoonoses, reverse zoonoses

Front 7

The AVMA has directed specialty groups to generate these guidelines

Back 7

Judicous Antimicrobial Use Guidelines

Front 8

Define "antimicrobial"

Back 8

An agent intended to harm or suppress a microbe

Front 9

Define "Antibiotic"

Back 9

An antimicrobial of natural origin

Front 10

Examples of natural antibiotics

Back 10

Pencillin, gentamicin, vancomycin, others

Front 11

The term that refers to a natural antibiotic that has been modified

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Semi-synthetic antimicrobial

Front 12

An example of a semi-synthetic antimicrobial

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Amoxicillin, ampicillin, ticarcillin

Front 13

An example of a synthetic antimicrobial

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Any fluorinated quinolone

Front 14

An example of a Gram positive organism generally characterized by low MIC

Back 14

Streptococcus toward for example, penicillns

Front 15

An example of a Gram negative organism generally characterized by low MIC

Back 15

Pasteurella toward many drugs

Front 16

An example of a Gram positive organism often characterized by high MIC

Back 16

Corynebacgterium, Staphylococcus

Front 17

An example of a Gram negative organism generally characterized by high MIC

Back 17

Pseduomonas, Enterobacter

Front 18

An example of a gram negative organism that is inherently multidrug resistant

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Pseudomonas aeruginosa

Front 19

An example of a gram positive organism that is inhterently multidrug resistant

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Enterococcus faecium

Front 20

The term used to refer to organisms exquisitively sensitive to the effects of oxygen

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Obligate anaerobes

Front 21

A term used to refer to a resident population of microbes

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Inoculum

Front 22

The term used to refer to a representative isolate from an inoculum

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A colony forming unit (CFU)

Front 23

The term used to refer to a commensal which becomes a pathogen

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An opportunist

Front 24

The term used to refer to an organism capable of causing harm to the patient

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Pathogen

Front 25

Two factors that indicate that a cultured isolate is the infecting pathogen

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Viability of growth, purity

Front 26

A factor that indicates that a cultured isolate is a pathogen

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Phagocytized organisms; selected molecular tests

Front 27

In the urine, the number of CFU indicative of possible infection

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10(3) to 10(5); 1,000 to 100,000

Front 28

The term used to refer to normal flora that colonize the hose without causing harm

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Commensals

Front 29

Actions through which commensals may contribute to host health

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Provide nutrients, control immune system, control populations of microbiota

Front 30

These factors allow a microbe to cause harm

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Virulence factors

Front 31

The first step in judicious antimicrobial use

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Assessing the need for teatment

Front 32

The second step in judicous antimicrobial use

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Identifying the infecting microbe/choose the drug

Front 33

The third step in judicious antimicrobial use

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Designing the dosing regimen

Front 34

A method by which an infecting microbe can be identified based on historical data

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Empirical selection

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This method of identifying an infecting microbe is the most specific for the patient's infection

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Culture and susceptibility testing

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The most common organism causing urinary tract infection in dogs

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Escherichia coli

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The most common organism causing pyodrma in dogs

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Staphylococcus pseudintermedius

Front 38

A first tier drug effective for treatment first time urinary tract infection

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amoxicillin/with or without clavulanic acid

Front 39

An example of an infection that might respond better to local non-antimicrobial therapy

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Feline Abscess, gutteral pouch disease in horses

Front 40

Revealing this in the history of a patient causes an infection to become "complicated"

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(Recent) previous antimicrobial therapy

Front 41

This structure on gram negative organisms presents as a barrier to drug penetration

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Lipopolysaccharide layer

Front 42

These factors allow a microbe to cause harm to a patient

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Virulence factors

Front 43

Define a "wild type" organism

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Retains original genome rather than genes for resistance

Front 44

An indication from the patient of "how much of an antimicrobial is needed" to target an infecting pathogen

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Minimum inhibitory concentration

Front 45

A population surrogate from indicators of "how much of an antimicrobial is needed" to target an infecting isolate

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90th percentile of a population of MIC (MIC 90)

Front 46

The "pharmacodynamic" indicator for microbials

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Minimum inhibitory concentration

Front 47

A "pharmacokinetic" parameter that indicates "how much drug is achieved" in the patient

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Peak plasma drug concentration (Cmax)

Front 48

The non-regulatory agency that sets standards for diagnostic- inlcuding Culture and Susceptibility - testing

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Clinical Laboratory Standards Institute (CLSI)

Front 49

This system allows simultaneous testing of multiple (eg, 8) drugs towards a microbe on a single plate

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Agar gel diffusion

Front 50

This system of susceptibility testing provides a concentration that is anticipated to be effective

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Tube dilution procedures

Front 51

The MIC of an isolate for amikacin is 16 mcg/ml and for enrofloxacin, 0.5 mcg/ml. As such, the isolate is more susceptible to enrofloxacin. Select one: True, False or Insufficient Information (I)

Back 51

I. You need to know Cmax. With Cmax provided, the statement would be true: comparing the Cmax to MIC, for enro at 4 mcg/ml (ratio = 8) the ratio is better compared to amikacin whose Cmax at the recommended dose is 64 mcg/ml (ratio = 4).

Front 52

True or False: All susceptibility testing involves two fold serial dilutions (or increase) of the drug of interest

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TRUE

Front 53

True or False: All susceptibility testing is implemented at 0.25 to 8 mcg/ml

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False: the range tested varies with the drug, reflecxting the Cmax achieved at the recommended dose

Front 54

A basis for the ranges of concentrations tested on a susceptibility panel for each drug

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The peak concentration of the drug achieved in the plasma at the recommended dose

Front 55

An isolate is tested at concentrations that range from 0.125 to 2 mcg/ml. Growth occurs up to (that is, at 0.125, 0.25) but not including 0.5 mcg/ml. What is the MIC?

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0.5 mcg/ml

Front 56

An isolate is tested at concentrations that range from 4 to 64 mcg/ml. Growth occurs in all the wells, including that containing 64 mcg/ml. What is the MIC?

Back 56

> 128 mcg/ml

Front 57

An isolate has an MIC of 1 mcg/ml. The breakpoint is < 4 mcg/ml (susceptible) and >8 mcg/ml (resistant). What will CLSI indicate the isolate to be?

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The isolate would be considered susceptible to the drug

Front 58

True or False: An isolate designated as "susceptible" to a drug will have no resistance genes for that drug

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False: The designation only refers to the susceptiblity test and whether or not the MIC is likely to be achieved in the patient at the recommended dose

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True or False: The "S, I or R" designation indicates the likelihood that the MIC for an isolate can be achieved when the dose is administered as the recommended dose

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TRUE

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A class of drugs to which Enterococcus sp is ineffective

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cephalosporins, aminoglycosides