Antimicrobials Flashcards
Gram Negative Bacteria (Salmonella, Pseudomonas, Neisseria, Gonorrhea, Klebsiella) Defined
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
Gram Positive Bacteria (Staphylococci, Streptococci, Enterococci) Defined
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
Macrolides “Mycins” MOA
Inhibition of bacterial protein biosynthesis
Macrolides “Mycins” Indications
Mycobacterium, atypical PNA, legionella, Chlamydia
Macrolides “Mycins” CTN
Prolonged QTc, CYP4503A4 Inhibitors
1st Cephalexin, Cefadroxil Indications
SSTI, UTI
Mostly gram-positive coverage
staphylococcus (non MRSA)
2nd Cefuroxime, Cefprozil Indications
SSTI, RTI’s
More gram-positive than gram-negative
3rd Cefdinir, Cefixime, Ceftriaxone Indications
Uncomplicated simple cystitis
RTI’s
4th Cefepime Indication
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).
5th Ceftaroline Indication
IV Anti-MRSA agent
Cephalosporin LAME pneumonic
±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).
PCN Allergy Type I: IgE Mediated, Hypersensitivity
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)
Amoxicillin Drug Rash: Facts
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
Fluoroquinolones: “Floxacin’s” Classes and Indications
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
Fluoroquinolones: “Floxacin’s” SE’s and CXN:
SE’s: Severe musculoskeletal effects, tendinopathies, prolonged QTc,
CXN: Avoid use with zinc containing products as it decreases ABX efficacy
Fluoroquinolones: “Floxacin’s” MOA
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)
Fluoroquinolones: “Floxacin’s” Black Box Warning
±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).
Tetracyclines “Cycline’s”
Tetracycline, Doxycycline, Minocycline
MOA
Binds to 30S subunit of microbial ribosomes and inhibits bacterial protein synthesis. BACTERIOSTATIC
Tetracyclines “Cycline’s”
Tetracycline, Doxycycline, Minocycline
SE’s
Tetracycline tooth staining - do not use during pregnancy or in children <8 yrs
Tetracyclines “Cycline’s”
Tetracycline, Doxycycline, Minocycline
CXN
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
Sulfonamides “Sulfa’s”
Trimethoprim, Sulfamethoxazole (TMP + SMX = Bactrim), Sulfasalazine (Azufidime)
Indications
UTI’s, Pneumocystis Jirovecii PNA, respiratory tract infections, toxoplasmosis, burn wound infections
Sulfonamides “Sulfa’s”
Trimethoprim, Sulfamethoxazole (TMP + SMX = Bactrim), Sulfasalazine (Azufidime)
MOA
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
Sulfonamides “Sulfa’s”
Trimethoprim, Sulfamethoxazole (TMP + SMX = Bactrim), Sulfasalazine (Azufidime)
CXN
Trimethoprim has similar properties to potassium sparing diuretic. Avoid use with ACEi/ARB especially with CKD 2/2 risk of dehydration. Teratogenic
Broad Spectrum vs Narrow Spectrum
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
Synergy in Treatment
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
Antibiotic Class Pneumonic
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
4 ABX classes that are Gram Positive or Gram Negative Specific
Glycopeptides / Vancomycin
Gram Positive
Lincosamides
Gram positive
AmiNOglycosides (NO = Neg)
Gram Negative
Macrolides
Gram Positive
