Intro to ID Flashcards
S. pneumoniae
GRAM + Cocci, pair
Aerobic
Community Acquired pneumonia, meningitis, sinusitis, and bacteremia
Group A Strep (GAS)
S. Pyogenes
GRAM+ Cocci, chain
Aerobic
Skin/soft tissue infections (SSTI), Upper Respiratory Infection (URI)
Staph aureus (including MRSA)
GRAM+ Cocci, cluster
Aerobic
SSTI, bacteremia/line infections, pneumonia, endocarditis, osteomyelitis
MRSA is a rising problem
Typical skin flora, but commonly associated with sepsis and line infections in hospital due to improper sterilization of line site.
Treat bacteremia for 14 days
B-lactams are not reliable empiric therapy for MRSA. Vanco usually first line
MSSA - use B-lactams over vanco
Enterococcus
faecalis or faecium
GRAM+ Cocci faecalis = single, pair, or chain faecium = pair or chain Aerobic UTI, intra-abdominal infections, and endocarditis
S. epidermidis
Coagulase-negative Staph
GRAM+ cocci, cluster
Aerobic
Typically not pathogenic
Nesseria
GRAM- Cocci
Aerobic
URI
Moraxella catarrhalis
GRAM- cocci
Aerobic
Respiratory infections
H. influenza
GRAM- Rod
Aerobic
URI, community acquired pneumonia
H. Pylori
GRAM- Rod
Aerobic
Stomach/Gut
Enterobacteriaceae E. coli Klebsiella sp. Proteus sp. Enterobacter sp. Citrobacter sp.
GRAM- Baccili, oxicase negative, gut colonizing rods
Aerobic
UTI, IA, health care acquired pneumonia, bacteremia
Non-fermenting
Pseudomonas
Acinetobacter
Stenotrophomonas
GRAM- Cocco-bacilli, bacilli, or rods
Aerobic
HCAP, diabetic foot infections, nosocomial infections
Bacteroides sp
GRAM-
Anaerobic
IA, colitis, “Aspiration” pneumonia
Clostridium difficile or perfringens
GRAM- bacilli, spore forming
Anaerobic
IA, colitis, “aspiration” pneumonia
Legionella sp.
Atypical infection
CAP, worst offender of Legionella infection, STD’s
Mycoplasma sp
Atypical infection
STD
Chlamydia
Atypical infection
STD
Penicillin
Covers GRAM+
DOC for GAS, S. pyogenes, Treponemia
Not very good anymore because of resistance. Must test S. pneumonia for susceptibility before using
Amoxicillin and Ampicillin
Covers GRAM+
Only effective for GRAM- organisms that do not product beta-lactamases
Nafcillin (IV)
Dicloxacillin (PO)
(Methicillin class)
Covers GRAM+
DOC for GAS, S. pyogenes, MSSA
Known as the “Anti-Staph” class, Dicloxicillin is under used!
Augmentin (PO)
ampicillin/sulbactam (IV)
Broad Spectrum, covers GRAM+/-, Anaerobes, and MSSA
Beta-lactamase inhibitor doesn’t improve pseudomonas coverage
Ticarcillin/clavulanate
Pipercillin/tazobactam
Broad Spectrum, covers GRAM+/-, Anaerobes, and MSSA
Beta-lactamase inhibitors provide good GRAM- coverage (esp pseudomonas)
Imipenem/Cilastin
Meropenem
Doripenem
Broad Spectrum, covers GRAM+/-
Not good for MRSA and Non-fermenting GRAM- (pseudomonas, acinetobacter, stenotrophomonas)
Ertapenem
Broader Spectrum, covers GRAM+/- and Anaerobes
No efficacy against pseudomonas, but good for diabetic and long-term infections
Aztreonam
GRAM-, including pseudomonas
Good for use in PCN allergy!!
Cephalexin (PO)
Cefazolin (IV)
Expected to cover MSSA, GAS, S. pyogenes, and E. coli
Poor S. pneumonia coverage
1st Gen
Cefuroxime (IV/PO)
Expected to cover H. influenza, S. pneumonia, and MSSA
Gen 2A
Cefotetan (IV)
Expected to cover Gut GRAM- poor coverage on anaerobes, increasing resistance supply problems Can increase INR Gen 2B
Ceftriaxone (IV/IM)
Good GRAM- coverage DOC for S. pneumonia Renally cleared Does not cover Pseudomonas 3A Gen
Ceftazadime (IV)
Expected to cover Pseudomonas and other GRAM-
Poor GRAM+ coverage
Can induce resistance
3B Gen
Cefepime (IV)
Expected to cover Pseudomonas and other GRAM- organisms
Improved GRAM+ coverage (MSSA)
Reports of neurotoxicity, monitor
4th Gen
Ceftaroline (IV)
Covers Enterococcus
5th Gen
Typical beta-lactam antibiotic ADRs (Penicillins, carbapenems, cephalosporins)
Allergic reaction/Rash
Diarrhea
Occasional neutropenia/thrombocytopenia
Intestinal Nephritis (Rare, more common with Nafcillin) May be seen as allergy-induced renal failure
Seizures (more common with Imipenem)
Drug fever (overall Rare)
Suprainfection (more common with carbapenems)
Macrolide antibiotic coverage and uses
Excellent: Atypical infections
Good: H. influenza, M. catarrhalis
Decent: S. pneumonia
Uses: URI and CAP
Macrolide antibiotic ADRs
Azith: Fever, different chemical class than others GI problems QT prolongation Inhibits CYP system, watch drug interactions
Ciprofloxacin
Excellent GRAM- coverage
Poor GRAM+ coverage (not good for CAP)
Inhibition of CYP1A2 (theophylline)
Rising resistance rates!!!
Levofloxacin
Enhanced GRAM+ coverage with same GRAM- coverage as cipro
Excellent Atypical coverage (better than macrolides)
Moxifloxacin
Enhanced GRAM+ coverage with same GRAM- coverage
Excellent Atypical Coverage (better than macrolides)
Not effective for UTIs because it doesn’t enter urine (use “above the belt”)
Use of fluoroquinolones in pseudomonas infections
This is the ONLY oral agent that covers pseudomonas!!
Cipro only covers GRAM-, so not effective for some pseudomonas cases (Ex: CAP)
Levo/Moxi have improved GRAM+ coverage, useful against all pseudomonas
fluoroquinolone ADRs
Tendonitis/tendon rupture
Glucose disturbances
QTC prolongation
Photosensitivity
Aminoglycoside Coverage
Covers Aerobic GRAM-
Reserved for “SPACE” drugs
SPACE drugs
Serratia Pseudomonas Acinetobacter Citrobacter Enterobacter
Aminoglycoside Toxicities
Nephrotoxicity - usually reversible, incidence declining
Ototoxicity - can induce deafness or balance problems. Usually irreversible, difficult to monitor
Paralytic at high doses - minimized through once daily dosing
Antibiotics used in double-coverage
Beta-lactams + aminoglycosides for the first 3-5 days
Why? SPACE bugs are serious systemic infections, need to limit resistance developed!
Vanco coverage
Cell Wall antibiotic, similar to beta-lactams
Good GRAM+ coverage (MRSA and C. diff)
**Increasing MRSA resistance
Vanco ADRs
Red Man Syndrome (flushing) - caused by histamine, give antihistamine to block reaction. can prevent or reverse by slowing the infusion
Nephrotoxicity and Ototoxicity - overall rare, more common at high doses
Drug Rash with Eosinophilia and Systemic Symptoms (DRESS)
When should metronidazole be used?
Gold standard for anaerobes such as B fragilis
DOC for C. diff
Metronidazole ADRs
neuropathies
metallic taste
disulfaram-like rxn (EtOH)
what does a positive D Test indicate?
potential for clindamycin resistance to develop over course of treatment for MRSA
clindamycin coverage
Anaerobes and GRAM+
good for aspiration pneumonia and MRSA
bad for bacteremias and endocarditis because it is bacteriostatic
clindamycin ADRs
rash
can cause C. diff infection
Doxycycline coverage
GRAM+ (MRSA and varying S. pneumonia)
GRAM-
Some Atypical
Used in COPD bacterial exacerbations, MRSA, and SSTI
Doxycycline ADRs
N/V
Rash
phototoxicity
Linezolid coverage
Broad GRAM+, good for MRSA
Linezolid ADRs
thrombocytopenia
N/V/D
Headache
neuropathies
Mild MAOI, potential for drug interactions (serotonin syndrome, etc.)
**Not well tolerated, do not use beyond 4 weeks!! Likely to develop neuropathies, lactic acidosis, and maybe blindness past this.
Daptomycin coverage
Broad GRAM + with bactericidal activity
good for MRSA, bacteremias, and endocarditis
***DO NOT USE WITH PNEUMONIAS
Daptomycin ADRs
Rhabdomyolysis
Reduce dose with statins
Tigecycline Coverage
Very broad spectrum
GRAM+ (including MRSA and VRE)
GRAM - (acinetobacter and stenotrophomonas)
Anaerobes
***DO NOT USE WITH PSEUDOMONAS AND PROTEUS
Tigecycline ADRs
N/V
Televancin Coverage
aerobic and anaerobic, GRAM+
Televancin ADRs
N/V
Metallic taste
Insomnia
Pearls to Prevent Antimicrobial Resistance
Vaccinations Remove unnecessary indwelling catheters Determine the appropriate time to stop Vanco Know local antibiograms Wash hands
Best choices for anaerobes
Metronidazole
Clindamycin
Beta-Lactamase inhibitors
Carbapenems
Worst choices for anaerobes
fluoroquinolones
some cephalosporins
tetracyclines
macrolides
SMZ/TMP ADRs
Allergy Rash (SJS) Agranulocytosis anemia drug interactions
why is it important to note intra-abdominal abscesses on a CT?
Often means anaerobes are present (most often many GRAM-, anaerobes, and enterococcus (if healthcare-acquired))
Start with broad-spectrum therapy, narrow when cultures are available
Probably requires surgical intervention
