Infectious Diseases Flashcards: Antibiotics & Key Terms (copy)

What do you call a disease that is spread from person to person?

communicable or contagious

What are the 3 primary factors that impact tx decisions in ID?

the bug/pathogen

the drug

the patient/host

Describe infection characteristics

infection site, severity, community/hospital acquired

The presence of infection is determined by..?

signs/symptoms

Antibiotic characteristics include..?

spectrum of activity and ability to penetrate the site of infection

What pt characteristics impact ID tx choices?

age, body weight, renal and hepatic function, allergies, comorbidities

Describe empiric tx

broad-spectrum antibiotics started before the pathogen is identified, targeting likely organisms

What kind of information does a gram stain provide?

categorizes shape/morphology of organisms present, provides quick preliminary results, does NOT identify the exact orgamism

What does a positive gram stain tell us?

organisms have a thick cell wall

What does a negative gram stain tell us?

organisms have a thin cell wall

What does it mean when organisms do not stain well with a gram stain?

atypical

What color is a positive gram stain?

purple or bluish (from the crystal violet stain)

What color is a negative gram stain?

pink/red (from taking up the safranin stain)

What are the gram positive rods?

Listeria monocytogenes

What are the gram positive cocci (GPC)?

Staphylococcus (including MRSA & MSSA) (clusters)

Streptococcus (pairs/chains)

Enterococcus (pairs/chains)

What are the anaerobes?

(+)

- clostridium

- peptostreptococcus (mouth flora)

(-)

- bacteroides

- prevotella (mouth flora)

What are the atypicals?

Mycoplasma pneumonia

Chlamydia

Legionella

Mycobacterium terboculosis

What are some enteric gram negative rods (enteric GNR)?

P. mirabalis

E. coli

Klebsiella

Enterobacter

What are some gram negative rods that do not colonize the gut?

Psudomonas

H. Influenzae

Providencia

h. pyrlori

What organisms can infect the CNS/Cause meningitis?

streptococcus (+)

N. meningitis (-)

H. influenzae (-)

Listeria (+)

What are some organisms that can infect the mouth?

peptostreptococcus (+ anaerobe)

prevotella (- anaerobe)

What are some organisms that can infect the URT?

GPC: streptococcus pyogenes (+), streptococcus pneumoniae (+)

GNR: H. influenzae (-)

What are some organisms that can infect the LRT (community)?

GPC: streptococcus pneumoniae (+)

GNR: H. influenzae (-)

Atypicals: Legionella, Mycoplasma, Chlamydophilia

Enteric GNR: P. mirabalis, E. coli, Klebsiella, Enterobacter

What are some organisms that can infect the LRT (hospital)?

MSSA, MRSA (+)

psudomonas (-)

acinetobacter (-)

Enteric GNR: P. mirabalis, E. coli, Klebsiella, Enterobacter (incl. ESBL & MDR)

What is ESBL?

extended spectrum beta-lactamase - resistance to cephalosporins and penicillins - generally treated with carbapenems or newer cephlasporins +beta lactase inhibitor combos

What is MDR?

multidrug resistance

What are some organisms that can infect the heart/cause endocarditis?

GPC: MSSA, MRSA, staph epidermis, streptococcus, enterococcus

What are some organisms that can cause SSTI?

GPC: MSSA (+), streptococcus pyrogenes, staph epidermidis

GNR: pseudomonas, H. influenzae, providencia, H. pylori (esp in pt w/ DM)

What organisms can infect the bones/joints?

GPC: MSSA (+), staph epidermidis, streptococcus

N. gonorrhoeae (-)

GNR: pseudomonas, h. influenzae, providencia, h. pylori

What organisms can cause IAI?

Enteric GNR: P. mirabalis, E. coli, Klebsiella, Enterobacter

Enterococcus (+)

Streptococcus (+)

Bacterioides (anaerobic)

What organisms can cause UTI?

GNR: E. coli, Klebsiella, P. mirabalis

Staph saprophyticus (GPC)

Enterococcus (GPC)

What is CFU?

colony forming units that grow on the agar plate in the lab. Represents # bacterial cells present in the culture

What is MIC?

Minimum inhibitory concentration: smallest concentration of drug that visibly inhibits growth.

(specific to each antibiotic and organism)

When an angiogram has a lot of susceptible antibiotics, how do you decide which to choose?

- most narrow spectrum

- pt factors (guidelines, need of IV, allergy, renal/hepatic function, etc)

What does it mean when an antibiotic is showing as intermediate in an angiogram?

it may be effected under certain circumstances (ex: higher doses, extended infusions, etc)

They are generally not accepted over a susceptible antibiotic

Describe the synergistic relationship between beta lactase and aminoglycosides

Used to treat invasive gram + infections like endocarditis

the beta lactic allows the aminoglycloside to reach its intracellular target (ribosome) where if can then cause lethal damage to the bacteria. w/out the beta lactic the amino glycoside cannot penetrate the cell wall at safe doses --> allows for reduced doses of the aminoglycoside and faster clearing of the infection.

Describe tx assessment after starting an antibiotic

1. fever trend

2. WBC trend

3. s/sx

Describe the different types of resistance

- Intrinsic: resistance is natural to the organism

- Selection Pressure: antibiotics kill off susceptible and leaves the resistant ones left to multiply, becoming more prominent

- Acquired: resistant gene transfer

- Enzyme Inactivation: enzymes produced by the bacteria break down the antibiotic (ex: ESBL, CRE)

What is CRE?

Carbapenem-resistant Enterobacteriaceae: MDR enteric GNR like Klebsiella & E. coli produce enzymes that can break down penicillins, most cephalosporins, and carbapenems.

They typically require multi drug regimen like polymyxins (that have high risk toxicity)

What are common resistant pathogens?

Kill Each And Every Strong Pathogen

Klebsiella pneumoniae (ESBL, CRE)

E. coli (ESBL, CRE)

Acinetobacter baumannii

Enterococcus faecalis, E. faecium (VRE)

Staphylococcus aureus (MRSA)

Pseudomonas Aeruginosa

What is VRE?

vancomycin resistant enterococcus

What is an antibiotic with a high risk for c. diff?

clindamycin

What are the DNA/RNA inhibitors?

Quinolones (DNA gyrase, topoisomerase IV)

Metronidazole, tinidazole

Rifampin

What are the Cell Membrane Inhibitors?

Polymyxin

Daptomycin

Telavancin

Oritavancin

What are the Protein Synthesis Inhibitors?

aminoglycosides

macrolides

tetracyclines

clindamycin

linezolid, tedizolid

quinupristin/dalfopristin

What are the Cell Wall Inhibitors?

beta-lactams (penicillins, cephalosporins, carbapenems)

monobactams (aztreonam)

Vancomycin ( & dalbavancin, telavancin, oritavancin)

What are the Folic Acid Synthesis Inhibitors?

Sulfonamides

Trimethoprim

Dapsone

What are the hydrophilic antibiotics?

BAD VP
Beta-lactams

Aminoglycosides

Daptomycin

Vancomycin

Polymyxins

What are the lipophilic antibiotics?

quinolones

macrolides

rifampin

linezolid

tetracyclines

chloramphenicol

What are the PK parameters of hydrophilic antibiotics?

- small Vd --> poor tissue penetration

- renal elimination --> drug accumulation if poor renal function

- low intracellular concentration --> not active against atypicals

- increased clearance/distribution in sepsis --> consider loading doses & aggressive dosing w/ sepsis

- lower bioavailability --> Not used PO or IV to PO generally not 1:1

What are the PK parameters of lipophilic antibiotics?

- large Vd --> good tissue penetration (inc. bone, lung, brain)

- hepatic metabolism --> risk hepatotoxicity & drug-drug interactions

- good intracellular concentration --> active against atypicals

- no changes to clearance/distribution in sepsis --> dose adj not needed in sepsis

- excellent bioavailability --> given PO OR IV to PO generally 1:1

Which antibiotics are concentration-dependent?

aminoglycosides, quinolones, daptomycin

Which antibiotics are exposure-dependent?

vancomycin, macrolides, tetracyclines, polymyxins

Which antibiotics are time-dependent?

Beta-lactams (penicillins, cephalosporins, carbapenems)

How do you maximize MIC in concentration-dependent antibiotics?

have higher peaks (increase efficacy) and have lower troughs (decreased toxicity) by giving larger doses and decreased frequency

How do you maximize MIC in exposure-dependent antibiotics?

increase exposure over time

How do you maximize MIC in time-dependent antibiotics?

maintain the drug level to increase MIC over the dosing interval by having shorter dosing intervals & extended/continuous infusions

What are the beta-lactams and how do they work?

penicillins, cephalosporins, carbapenems

Beta-lactams MOA

They are characterized by a beta-lactam ring. They bind to penicillin binding proteins which prevents peptidoglycan synthesis --> inhibiting bacterial wall synthesis

What are all penicillins NOT active against?

MRSA or atypical organisms

What are the natural penicillins and what do they cover?

penicillin V, penicillin G

cover streptococcus, enterococcus, gram + anaerobe (mouth flora peptostreptococcus)

(Little gram - , NO STAPH)

What are the antistaphylococcal penicillins and what do they cover?

Nafcillin

Oxacillin

Dicloxacillin

cover streptococcus and MSSA

(NO gram -, enterococcus, or anaerobes)

What are the amino penicillins and what do they cover?

amoxicillin, ampicillin

(+)

strep, enterococcus, gram + anaerobe (mouth flora peptostreptococcus)

(-)

h. influenzae, p. mirabalis, E, coli

Why are aminopenicillins combined with beta-lactimase inhibitors and how does this change coverage?

allows coverage MSSA

More gram (-): Klebsiella + h influenzae, neisseria, p. mirabalis, e. coli (HNPEK)

Added gram (-) anaerobes like bacterioides fragilis

What is the extended spectrum penicillin and what is its coverage?

piperacillin/tazobactam

Same as amibopenicillin + beta lactase inhibitors:

MSSA

(-): HNPEK

gram (-) anaerobes like bacterioides fragilis

PLUS expanded gram - coverage CAPES + pseudomonas

What is HNPEK?

Haemophilus (GNR), Neisseria (GNC), Proteus (enteric GNR), E. coli (enteric GNR), Klebsiella (enteric GNR)

What is CAPES?

Citrobacter (enteric GNR), Acinetobacter (-), Providencia (GNR), Enterobacter (enteric GNR), Serratia (enteric GNR)

Which penicillins come as INJ?

penicillin G aq, nafcillin, ampicillin, Unasyn, Zosyn

What is the brand name for amoxicillin/clavulanate?

Augmentin

What is the brand name for ampicillin/sulbactam?

Unasyn

What is the brand name for piperacillin/tazobactam?

Zosyn

What penicillins come a chewable?

amoxicillin and Augmentin

Which penicillin has a BBW for IV use?

penicillin G benzathine

only penicillin G aqueous can be used IV

What antibiotics require renal adjustments?

beta lactams (CI in penicillins if CrCl < 30, beside antistaphyloccocus penicillins)

aminoglycosides

Vancomycin

Polymyxins

What adjustments should be made if a pt CrCl <30 and they are on augmentin?

do not give ER , max dose 875 mg

Penicillins: SEs

seizures with accumulation, GI upset, diarrhea, rash (incl anaphylaxis, SJS), hemolytic anemia

Which penicillins are preferred for MSSA?

antystaphylococcus: dicloxacillin, nafcillin, oxacillin

How is ampicillin given and why?

IV due to poor bioavailability

How is Zosyn given?

prolonged or extended IV infusions over 4h

What medication can increase the concentration of penicillins?

probenecid

What is the brand name for penicillin G benzathine?

Bicillin L-A

Which penicillin has pseudomonas coverage?

Zosyn

Which penicillin is used for h. pylori infection?

Amoxicillin

What are all cephalosporins NOT active against?

enterococcus and atypicals

How does coverage change among the cephalosporin generations?

1st: strep, staph The least gram (-)

2nd:

cefuroxime: more resistant strep, more gram (-) incl anaerobe

3rd:

Group 1 - : resistant strep, MSSA, gram + anaerobes, resistent gram -

Group 2 - ceftazidine pseudomonas

4th: Pseudomonas (broad gram -)

5th: like resistent gram -, broad gram + incl MRSA

Describe coverage of beta-lactamase inhibitor + cephalosporin

MDR pseudomonas, MDR GNR (PEK/CAPES)

What are the first generation cephalosporins and what do they cover?

cefazolin, cephalexin

cover strep, staph (preferred for MSSA), PEK

What is the brand name for cephalexin?

Keflex

What are the second generation cephalosporins and what do they cover?

cefuroxime: staph, more resistant strep, HPNEK

cefetetan & cefoxitin: same + gram (-) anaerobe bacterioides fragilis

What are the 3rd generation cephalosporins and what do they cover?

Group 1 - : ceftriaxone, cefotaxime, cefdinir: resistant strep, MSSA, gram + anaerobes (mouth flora peptosptrep, c.diff), resistant HNPEK

Group 2 - ceftazidine: pseudomonas

What are the 4th generation cephalosporins and what do they cover?

cefepime

broad gram (-): HPNEK, CAPES, pseudomonas

resistent strep, MSSA, gram + anaerobe

What are the 5th generation cephalosporins and what do they cover?

ceftaroline

resistant HPNEK, broad gram + (MSSA, strep), MRSA

How is Keflex PO dosed?

250-500 mg q6-12h

What is the brand name for cefotetan?

Cefotan

What is the brand name for ceftazidime?

Fortaz

What is the brand name for cefuroxime?

Ceftin

Ceftriaxone: CIs

Can cause high bilirubin in neonates --> biliary slugging and kernicterus (brain damage). Do not use concurrently with Ca-containing IV products in neonates <28 days old

What antibiotics have cross-sensitivity with penicillin allergy?

cephalosporins

carbapenems

What are warnings specific to cefotetan?

increased risk bleeding due to side chain

increased risk disulfiram-like rxn (hangover sx) with alcohol

Cephalosporin: SEs

seizures with accumulation, GI upset, diarrhea, rash/allergy, hemolytic anemia, severe skin rxns like SJS/TEN