Antimicrobials

Question 1

Gram Negative Bacteria (Salmonella, Pseudomonas, Neisseria, Gonorrhea, Klebsiella) Defined

Answer 1

Negative bacteria have a MUCH thinner cell wall, consisting of a single layer of peptidoglycan. This layer of peptidoglycan is sandwiched between two lipid bilayer membranes called diderms.
A thinner cell wall and will lose the violet stain
Gram-Negative Cell Walls Are High in Lipids
High resistance

Question 1

Gram Positive Bacteria (Staphylococci, Streptococci, Enterococci) Defined

Answer 1

Positive have a thick cell wall, which consists of up to around 30 layers of peptidoglycan. This cell wall surrounds a monoderm, which is a single plasma membrane
Contain a thick cell wall and retain a purple color after staining
Peptidoglycan picks up the purple stain
Gram-Positive Cell Walls Are Low in Lipids

Question 2

Macrolides “Mycins” MOA

Answer 2

Inhibition of bacterial protein biosynthesis

Question 3

Macrolides “Mycins” Indications

Answer 3

Mycobacterium, atypical PNA, legionella, Chlamydia

Question 4

Macrolides “Mycins” CTN

Answer 4

Prolonged QTc, CYP4503A4 Inhibitors

Question 5

1st Cephalexin, Cefadroxil Indications

Answer 5

SSTI, UTI
Mostly gram-positive coverage
staphylococcus (non MRSA)

Question 6

2nd Cefuroxime, Cefprozil Indications

Answer 6

SSTI, RTI’s
More gram-positive than gram-negative

Question 7

3rd Cefdinir, Cefixime, Ceftriaxone Indications

Answer 7

Uncomplicated simple cystitis
RTI’s

Question 8

4th Cefepime Indication

Answer 8

Possessing high intrinsic potency due to rapid penetration into the periplasmic space; an extended spectrum of activity that includes many Gram-positive and Gram-negative organisms; also good for pseudomonal coverage (inj only, therefore inpatient guided).

Question 9

5th Ceftaroline Indication

Answer 9

IV Anti-MRSA agent

Question 10

Cephalosporin LAME pneumonic

Answer 10

±L-Does not cover listeria
±A- Does not cover atypical pneumonias (i.e., mycoplasma, chlamydia, and legionella)
±M- Does not have MRSA coverage (exempt for 5th gen- only used w inpatients).
±E- Does not have enterococci coverage (exempt for ampicillin that can be used in enterococcal endocarditis).

Question 11

PCN Allergy Type I: IgE Mediated, Hypersensitivity

Answer 11

Immediate, Anaphylactic
Preferential production of IgE in response to certain antigens
Involves: Skin (urticaria), eyes (conjunctivitis), nose (rhinorrhea, rhinitis), bronchopulmonary tissues (wheeze, cough) and/or GI tract (gastroenteritis)

Question 12

Amoxicillin Drug Rash: Facts

Answer 12

Maculopapular rash, non-itchy
Start a number of days into therapy to one week of therapy
Etiology: delayed cell-mediated immune reaction
Not considered a true allergic reaction
Can continue to use PCN

Question 13

Fluoroquinolones: “Floxacin’s” Classes and Indications

Answer 13

2nd Generation: Ciprofloxacin (Cipro)
Cover P Aeruginosa
3rd Generation or Resp FQ: Levofloxacin (Levaquin), Moxifloxacin (Avelox), Gemifloxacin (Factive)
Antipneumococcal Activity given the activity against streptococcus pneumoniae
Levofloxacin
Cover P Aeruginosa
Antipneumococcal Activity given the activity against streptococcus pneumoniae

Question 14

Fluoroquinolones: “Floxacin’s” SE’s and CXN:

Answer 14

SE’s: Severe musculoskeletal effects, tendinopathies, prolonged QTc,
CXN: Avoid use with zinc containing products as it decreases ABX efficacy

Question 15

Fluoroquinolones: “Floxacin’s” MOA

Answer 15

MOA: Inhibits bacterial DNA thereby inhibiting DNA replication transcription. BACTERICIDAL
All FQ’s have activity for anaerobic gram negative bacteria
°SAVE for Pseudomonas aeruginosa (chronic lung dz (CF), CAP w multiple comorbidities, pyelonephritis, malignant OE (DM) immunocompromised (AIDS)

Question 16

Fluoroquinolones: “Floxacin’s” Black Box Warning

Answer 16

±Risks include: rare potentially permanent side effects that involve tendons, nerves, muscles, joints and CNS (tinnitus, fatigue, poor concentration)
±Don’t forget that FQs are QTc prolonging, AND put patients at risk for Clostridium difficile infection (CDI).

Question 17

Tetracyclines “Cycline’s”
Tetracycline, Doxycycline, Minocycline
MOA

Answer 17

Binds to 30S subunit of microbial ribosomes and inhibits bacterial protein synthesis. BACTERIOSTATIC

Question 18

Tetracyclines “Cycline’s”
Tetracycline, Doxycycline, Minocycline
SE’s

Answer 18

Tetracycline tooth staining - do not use during pregnancy or in children <8 yrs

Question 19

Tetracyclines “Cycline’s”
Tetracycline, Doxycycline, Minocycline
CXN

Answer 19

Photosensitivity, Esophagitis, Cat D pregnancy (avoid), Avoid Mg + Ca + Fe + Al (tums), Avoid dairy by 2 hours as it causes reduced absorption due to its chelation effect

Question 20

Sulfonamides “Sulfa’s”
Trimethoprim, Sulfamethoxazole (TMP + SMX = Bactrim), Sulfasalazine (Azufidime)
Indications

Answer 20

UTI’s, Pneumocystis Jirovecii PNA, respiratory tract infections, toxoplasmosis, burn wound infections

Question 21

Sulfonamides “Sulfa’s”
Trimethoprim, Sulfamethoxazole (TMP + SMX = Bactrim), Sulfasalazine (Azufidime)
MOA

Answer 21

MOA: Folate synthesis inhibition by competitive inhibition of enzyme that catalyzes conversion of PABA to dihydropteroate, a key step in folate synthesis needed for cellular division. BACTERIOSTATIC

Question 22

Sulfonamides “Sulfa’s”
Trimethoprim, Sulfamethoxazole (TMP + SMX = Bactrim), Sulfasalazine (Azufidime)
CXN

Answer 22

Trimethoprim has similar properties to potassium sparing diuretic. Avoid use with ACEi/ARB especially with CKD 2/2 risk of dehydration. Teratogenic

Question 23

Broad Spectrum vs Narrow Spectrum

Answer 23

Initial treatment often starts with broad-spectrum antibiotics while awaiting culture results, which can then be tailored to more specific, narrow-spectrum agents based on pathogen susceptibility

Question 24

Synergy in Treatment

Answer 24

certain infections, especially in immunocompromised patients or multi-drug resistant organisms, require the use of combination therapy to enhance efficacy and reduce the risk of resistance

Question 25

Antibiotic Class Pneumonic

Answer 25

Antibiotics = Aminoglycosides
Can = Cephalosporins
Terminate = Tetracyclines “Cyclines”
Protein = Penicillins “Cillins” / Beta Lactams
Synthesis = Sulfonamides “Sulfas”
For = Fluoroquinolones “Floxacins”
Microbial = Macrolides “thromycin”
Cells = Carbapenems “Penem”
Like = Lincosamides “Mycin”
Germs = Glycopeptide, Vancomycin most common

Question 26

4 ABX classes that are Gram Positive or Gram Negative Specific

Answer 26

Glycopeptides / Vancomycin
Gram Positive
Lincosamides
Gram positive
AmiNOglycosides (NO = Neg)
Gram Negative
Macrolides
Gram Positive