Infectious Diseases Flashcards
Recognize common organisms + groups of organisms Focus on resistant organisms and drugs that treat them Remember spectrum of activity for antimicrobial classes Practice assessing patient profiles for the exam
Communicable disease VS. non communicable
contagious, spread from person to person
Non-communicable disease: heart disease, stroke, HTN, DM
Hospital acquired infections are usually involving _______ _________ __________ organisms
multidrug resistant (MDR)
In order to diagnose a true infection, we need _________ & ______ in addition to positive culture
signs and symptoms
(Lipophilic? or Hydrophilic?) antibiotics are able to penetrate tissue better and resolve infections
lipophilic
The way a drug is cleared can determine the efficacy it has - ex: non renally cleared drugs may not reach adequate drug concentrations in the urine if that’s the target (UTI)
that’s it thats all
What patient characteristics can impact treatment choices
age, body weight, renal function, hepatic function, allergies, recent antibiotic use, pregnancy, immune function, comorbid conditions, vaccination status, environmental exposure, colonization with resistant bacteria
Common bacteria for CNS/Meningitis
Strep. pneumoniae
Neisseria meningitis
H. Influenzae
Group B Strep/ Ecoli (young pts)
Listeria (young/old)
Common bacteria that cause Upper Respiratory Infections
Strep. pyogenes
Strep. pnuemoniae
H. influenzae
Morexalla Catarrhalis
Common bacteria that cause Heart infections/Endocarditis
Staph. Aureus (including MRSA)
Staph. Epidermidus
Streptococci
Enterococci
Common bacteria that cause skin/ soft tissue infections
Staph. aureus
Staph. epidermidus
Strep. pyogenes
Pasteurella multocida
(+/- aerobic/anaerobic gram negative rods (GNR) in diabetes)
Common bacteria that cause bone/joint infections
Staph. aureus
Staph epidermidus
N. gonorrheae
Streptococci
GNR only in specific situations
Common bacteria that cause infections in the mouth
Mouth flora (peptostreptococcus)
Anaerobic GNR (prevotella, others)
Viridans group streptococci
Common bacteria that cause community acquired lower respiratory infections
Strep pneumoniae
Haemophilus influenzae
Atypicals: Legionella, Mycoplasma, Chlamydophilia
Enteric GNR in alcoholics
Common bacteria that cause hospital acquired lower respiratory infections
Staph aureus (including MRSA)
Pseudomonas aeruginosa
Acinetobacter baumannii
Enteric GNR (including ESBL, MDR)
Strep pneumoniae
Common bacteria that cause intra-abdominal infections
Enteric Gram Negative Rods
Enterococci/Strepcocci
Bacteroides Species
Common bacteria that cause Urinary Tract Infections
E Coli
Proteus
Klebsiella
Staph. Saprophyticus
Enterococci
Gram negative organisms
Thin cell wall, pink or reddish color from safranin counterstain
peptidoglycan is thin
Gram positive organisms
Thick cell wall, dark purple or blueish from the crystal violet stain
Peptidoglycan is thick
Atypical organisms
(ex: legionella, mycoplasma, chlamydia, mycobacterium tuberculosis) they don’t have a cell wall and don’t stain well.
Types of gram positive bacteria morphology under a microscope
Positive = Purple
Cocci (types: clusters, pairs (diplococci), and chains)
Bacilli aka rods
Anaerobes aka spores
Types of cluster (cocci) bacteria (Gram positive)
staphylococcus spp. (including MRSA, MSSA)
Types of pair & chain (cocci) bacteria (Gram positive)
strep. pneumoniae (diplococci = pair)
streptococcus spp.
enterococcus spp. (including VRE)
Types of rod (baccili) bacteria (gram positive)
Listeria monocytogenes
corynebacterium spp.
Types of gram positive anaerobes
Peptostreptococcus ( mouth flora)
Propionibacterium acnes
Clostridioides difficile
Clostridium spp.
Gram negative bacteria (pink) morphology includes
Cocci
Rods (that either colonize in the gut or don’t or curved/or spiral shaped)
Anaerobes
Coccobaccili (rod pairs /oval shaped)
Types of cocci (gram negative)
Neisseria spp.
Types of enteric rods (colonize the gut) (gram negative)
Proteus mirabilis, Escherichia coli, Klebsiella spp.
aka [PEK]
Serratia spp.
Enterobacter cloacae
Citrobacter spp.
Types of curved or spiral shaped rods (gram negative)
H pylori, campylobacter spp., treponema spp., borrelia spp., leptospira spp.
Types of rods that don’t colonize in the gut (gram negative)
pseudomonas aeruginosa
haemophilus influenzae
providencia spp.
types of coccobacilli (rod pairs /oval shaped) gram negative
Acinetobacter baumannii
Bordetella pertussis
Moraxella catarrhalis
Types of gram negative anaerobes
Bacterioides fragilis
Prevotella spp.
what is HNPEK
Haemophilus Influenzae
Neisseria
Proteus
E. coli
Klebsiella
what is CAPES
Citrobacter
Acinetobacter
Providencia
Enterobacter
Serratia
How is an antibiogram used
To determine the empiric therapies that can be used and help review resistance trends. Shows susceptibility patterns over a specific period (usually 1 yr) at an institution. The numbers show the percent susceptibility of each organism to the drugs
coccus, cocci, diplococci meaning
coccus - single
cocci - multiple
diplococci - pairs
What is an MIC
The minimum inhibitory concentration which is the lowest concentration with no bacterial growth
if the MIC is below the breakpoint, this means it is a good antibiotic to use!
We should never compare MIC’s between one antibiotic to another! Their values are specific to their minimum inhibitory concentration. We need to choose the MIC with the NARROWEST spectrum and (you have to know that part in your head, there’s no number associated with that)the one that is specifically best for the patient
What is the breakpoint
It is set by the clinical laboratory and standards institute and it is a standardized value for the concentration at which a particular bacteria was found to be susceptible to a particular drug
If the MIC is below the break point, it is susceptible, if it is one above the breakpoint, it’s intermediate, if it’s four above the breakpoint, its resistant
Synergy
Using two antibiotics to get a bigger benefit than just one antibiotic
sequence for choosing antibiotic therapy
- identify the organism through a culture
- check the susceptibility of the organism to different antibiotics
- determine with antibiotics have MIC’s below the break point
- determine which antibiotic has the narrowest spectrum and is the best for the specific patient (consider renal function, ability to penetrate specific area, drug interactions, dosage form, allergies, duration, adherence, inability to tolerate SE etc.)
How do we choose empiric treatment
- Think of the drugs that target the common organisms that infect the area where the current infection is.
- If there is a risk for MRSA, provide coverage
- Use the antibiogram and gram stain, if available, to narrow treatment selection
When the culture and susceptibility results come back in 24-72 hours, alwayssssss SET A TIME FRAME FOR THE ANTIBIOTICS! NEVER ALLOW THEM TO CONTINUE UNNECESSARILY
How should we monitor and assess the patients response to antibiotic treatment
- See their fever reduce and other vitals like O2 sat
- WBC trend
- Check notes for a reduction in the signs and symptoms of that particular infection
- Improved things like chest xrays, reduced markers of inflammation (procalcitonin, CRP, and ESR), repeat blood or CNS cultures - remember we DO NOT need to repeat sputum or urine cultures
E coli is resistant to vancomycin because
Vancomycin is too large to penetrate into Ecoli’s cell wall.
What is selection pressure
Another type of resistance.When an antibiotic kills off the bacteria that are susceptible to it, but it leaves behind the resistant bacteria and then they are able to multiply and become predominant which is a PROLEM!
Acquired vs. Intrinsic resistance
Intrinsic - the bacteria is naturally resistant to the antibiotic (ex: Ecoli and vancomycin because vancomycin is too large to penetrate the cell wall of ecoli)
Acquired - the bacterial DNA that has resistant genes is transferred from one species to another or picked up from dead fragments in the environment.
Describe enzyme inactivation and some examples
the bacteria naturally has enzymes that break down an important component of the antibiotic and reduces its effectiveness and enhances it’s resistance
Bacteria that produce beta lactamases break down beta lactams (ex: penicillins, cephalosporins, etc.) before they can reach their site of activity. We can use beta lactamase inhibitors like clavulanate, sulbactam, tazobactam, avibactam to prevent the enzymes from impacting the drug performance
ESBL’s - extended spectrum beta lactamases: enzymes that can break down all penicillins and most cephalosporins- very hard to kill and cause serious infections even with beta lactamase inhibitors. We typically use carbapenems or cephalosporin/beta lactamase inhibitor combinations
Carbapenem resistant enterobacteriacecae (CRE) are MDR gram negative organisms like Klebsiella and ecoli that produce enzymes like carbapenemases that break down penicillins and most cephalosporins and carbapenems. We use combinations of high intensity, toxic, and expensive drugs like polymixins, avibactam, and ceftazadime to kill these bacteria — this would be an advanced case of needing an ID pharmacist/antibimicrobial stewardship team to help with.
What are some common resistant pathogens and how are they resistant
“Kill each and every strong pathogen”
Klebsiella pneumoniae - ESBL, CRE
Escherichia coli - ESBL, CRE
Acinetobaceter
Enterococcus faecalis, Enterococcus faecium (VRE)
Staphylococcus aureus (MRSA)
Pseudomonas Aeruginosa
How does a C. Difficile infection occur
Clostridioides Diff. spores are present in normal gut flora, but it’s when the good healthy GI flora are killed off that resistant organisms have a chance to grow, become activated, and produce toxins. C diff does this and causes inflammation to the GI mucosa and causes a super infection. All antibiotics have a risk of causing this but especially broad spec. penicillins, cephalosporins, quinolones carbapenems, and BLACK BOX WARNING: CLINDAMYCIN not because it’s the worst offender but because it was the first offender to be identified but quinolones and broad spec. have more problems with this
Symptoms can be - mild: diarrhea, abdominal cramping severe: pseudomembranous colitis which can require a colectomy or be fatal. C diff infections continue to be difficult to treat
What does an anti-microbial stewardship program too
-Improve pt safety and outcomes
curb resistance to drugs
improve cost efficacy
Interventions ex:
- monitoring PK of aminoglycosides and vancomycin
- using clinical decision support software to help identify pathogens and reduce time to starting therapy
- pre-authorization of select antimicrobials (some antibiotics can’t be ordered unless antimicrobial steward team is consulted)
- prospective audit and feedback to prescribers of selected antibiotic
- timely transitions from IV to PO
Generally what types of antibiotics are bacteriocidal
The cell wall/membrane inhibitors, DNA/RNA inhibitors, aminoglycosides are bacteriocidal (kill bacteria)
Generally, what types of antibiotics are bacteriostatic ( inhibit bacterial growth)
Most protein and folic acid synthesis inhibitors
Example of synergy can be accomplished if we are able to pair one of these drugs with a cell wall/membrane inhibitor in order to allow the drug to even get inside the cell)
Which antibiotics are folic acid synthesis inhibitors
Sulfonamides
Trimethoprim (often combined with sulfamethoxazole overcome resistance)
Dapsone
Which antibiotics are cell wall inhibitors
Beta lactams (penicillins, cephalosporins, carbapenems)
Monobactams (aztreonam)
Vancomycin, dalbavancin, televancin, oritavancin
Which antibiotics are protein synthesis inhibitors
Aminoglycosides
Macrolides
Tetracyclines
Clindamycin
Linezolid, tedizolid
Quinupristin/Dalflopristin
Which antibiotics are cell membrane inhibitors
Polymixins
Daptomycin
Telavancin
Oritavancin
Which antibiotics are DNA/RNA inhibitors
Quinolones (DNA gyrase, topoisomerase IV, metronidazole, tinidazole, rifampin)
What are examples of hydrophillic agents
Beta-lactams
Aminoglycosides
Vancomycin (glycopeptides)
Daptomycin
Polymixins
What are four key characteristics of hydrophilic agents and why is it important to remember and contrast with lipophilic
- Small VD and low intracellular concentrations = poor tissue penetration and not active against intracellular pathogens
- Renally excreted - must consider dose adjustments to avoid drug accumulation SE like nephrotoxicity and seizures
- Increased clearance and/or distribution in sepsis so we need to use loading doses and higher doses
- Poor /moderate bioavailability (ability to reach circulation/serum concentrations), so it’s usually not used orally unless you need it to reach a specific area (ex: oral vanc for c diff) , or the IV: PO ratio is not 1:1
What are four key characteristics of lipophilic drugs and contrast with hydrophilic
- High VD and high intracellular concentrations = great tissue penetration and active against intracellular pathogens
- Hepatically excreted - must consider dose drug interactions and hepatotoxicity
- Normal clearance and/or distribution in sepsis so we can use normal doses/no adjustments needed
- Great bioavailability (ability to reach circulation/serum concentrations) IV: PO ratio is 1:1
What are examples of lipophilic agents
Quinolones
Macrolides
Rifampin
Linezolid
Tetracyclines
What is the difference between concentration dependent killing and time dependent killing and example drugs
Conc. dependent drugs are given in larger doses with longer time intervals in between so our goal with these is to see high peak (killing) and low troughs (toxicity). Cmax: MIC
- Aminoglycosides, quinolones, daptomycin
another ex of conc. dependent is AUC:MIC and it’s used in a similar way where we try to maximize the pts exposure to the drug over time.
Time > MIC – Time dependent killings drugs are given in more frequent time interval or each dose can have a longer administration/infusion time so that the concentration can be maximized above the MIC. So we can do extended or continuous infusions or shorter dosing intervals to try to maintain the drug level above the MIC for most of the dosing interval
- Beta lactams (penicillins, cephalosporins, and carbapenems)
Describe AUC: MIC (exposure/concentration dependent) and mention the drugs that rely on it.
goal is to increase the bacterias exposure to the drug over time using variable dosing strategies
EX: Vancomycin, macrolides, tetracyclines, polymixins
What categories of abx are beta lactams
penicillins, cephalosporins, carbapenems
beta lactam abx MOA/description
All of them have a beta lactam ring
They bind to penicillin binding proteins (normally would help build peptidoglycan in cell wall) and inhibit the cell wall synthesis.
True or false: penicillins are able to cover MRSA and atypical organisms
False. Penicillins do not cover MRSA or atypical organisms
Which penicillins are “natural” and what are their doses/forms
Penicillin V Potassium PO (tablet or susp.)
125- 500 mg Q6 -12 hrs on empty stomach
Penicillin G Aqueous IV
2-4 million units Q4-6 H
**Penicillin G Benzathine (Bicillin L-A) or Pen G Benzathine +Pen G Procaine (Bicillin C-R) INTRAMUSCULAR ONLY !!
1.2-2.4 million units one time (freq. varies)
- Pen G Benzathine is only IM never IV because it can cause cardiorespiratory arrest and death!
Which penicillins are anti-staphylococcus & what are their doses/forms and important points
Dicloxacillin (capsule)
PO: 125-500 MILLIGRAMS Q6H
Nafcillin (inj.)
IV/IM: 1-2 grams Q4-6H
- This is a vesicant and extravasation can occur (leaky vessels), so we should use cold packs and hyaluronidase injections
Oxacillin (inj.)
IV: 250-2,000 MILLIGRAMS Q4-6H
These are preferred for MSSA soft tissue, bone & joint, endocarditis and blood stream infections
- These DON’T need renal dose adjustments
Which the aminopenicillins and what are their doses/forms and important counseling points for each
** Amoxicillin (PO - chew, tab., susp., caps.)
varied dosing, 24h ER tab is one daily
- this is rarely used bc PO has poor bioavailability!!
- CI: if CrCl< 30 ml/min, NEVER use XR amox, or XR forms augmentin or the 875 mg dose of augmentin
** Amoxicillin/Clavulanate (Augmentin, Augmentin ES-600) - (PO: tab, chew, susp.)
varied dosing, XR tablet Q12H with food
- use a 14:1 ratio of amox/clav to reduce diarrhea caused by clauv
- CI: NEVER use Augmentin or Unasyn if history of cholestatic jaundice or hepatic dysfunction assoc. with prev. use.
- CI: if CrCl< 30 ml/min, NEVER use XR amox, or XR forms augmentin or the 875 mg dose of augmentin
**Ampicillin (Inj. - IV/IM & PO - capsule, susp.)
PO - 250 - 500 MG Q6H on empty stomach 1 hr before or 2 hrs after a meal
IV/IM 1-2 GRAMS Q4-6H
- must be diluted in NS ONLY
**Ampicillin/sulbactam (Unasyn) - Inj.
IV/IM 1.5-3 GRAMS Q6H
- must be diluted in NS ONLY
- CI: NEVER use Augmentin or Unasyn if history of cholestatic jaundice or hepatic dysfunction assoc. with prev. use.
Which penicillin is extended spectrum and what is important to know about sodium content
Piperacillin/Tazobactam (Zosyn) - Inj.
IV: 3.375 g Q6H or 4.5 g Q 6-8 H
PROLONGED EXTENDED INFUSIONS:
3.375-4.5 g IV Q8H (each dose infused for 4 hrs)
There are 65 g Na per 1 g of Pip/Tazo
What are general side effects and monitoring points for all penicillins
SE:
- seizures can occur if drugs accumulate when not correctly dosed in pts with renal dysfunction
- GI upset, diarrhea, rash (SJS/TEN/allergy/anaphylaxis, hemolytic anemia), renal failure, myelosuppression with prolonged use, increased LFTs
Monitoring:
renal function, symptoms of anaphylaxis with 1st dose , CBC, LFT’s with prolonged course
Interactions:
- Probenacid (gout drug) can increase the levels of beta lactams because it decreases renal excretion - sometimes this combo is used intentionally in severe infections!
- Warfarin: beta lactams inhibit vitamin K dependent clotting factors which increases warfarins anticoagulation activity. (except naf/dicloxacillin- they actually do the opposite and decrease warfarins effectiveness)
- Penicillins increase the serum concentration of methotrexate and can decrease the conc. of mycophenolate active metabolites due to impaired enterohepatic recirculation
What do natural penicillins cover
Gram + cocci (strep, enterococci, but NOT staph) and Gram + anaerobes (mouth flora)
They do not cover gram -
Antistaphylococcal penicillins cover…
Streptococci,
*** MSSA (enhanced coverage for)
NO activity against enterococcus, gram neg. pathogens and anaerobes, or MRSA
What do aminopenicillins cover
Strep
Enterococci
Gram positive anaerobes (mouth flora)
With the addition of the amino group, it can cover. (HNPE) Haemophilis, Neisseria, Proteus, E coli - if combined with a beta lactamase inhibitor, it creates a broad spectrum of activity for the Klebsiella too (HNPEK) and
Gram negative anaerobes (B. fragilis)
What do extended spectrum penicillins in combo with beta lactamase inhibitor (pip/tazo) cover
(very broad SOA)
Cover anything that aminopenicillins/beta lactamases cover with the addition of
Pseudomonas, CAPES (nosocomial bacteria)
Generally, all penicillins cover _______ but they dont cover ______
generally cover enterobacter - except for the anti-staph penicillins
They never cover MRSA or atypicals (due to lack of cell wall)
Always avoid penicillins in patients with
- ANY beta lactam allergy (penicillins, carbapenems, cephalosporins) - unless treating syphilis in pregnancy or in patients with poor compliance/follow up – in these cases we can desensitize patients and treat them with Pen G benzathine
- Seizure history or you notice they are on seizure medications AND renal dysfunction. Because any beta lactam is a hydrophillic drug and if it accumulates in the kidney this can cause seizures (not as common to get beta lactam related seizures)
Which penicillins can be taken outpatient (PO)? for what indications and give doses if needed
Penicillin VK - K is for Potassium (first line for strep throat, non purulent skin infection without abscess, or tooth abscess)
Amoxicillin aka “amox- tag”
- First line treatment for acute otitis media (pediatric dose is 80-90 mg/kg/day max PO)
- Drug of choice for infective endocarditis prophylaxis before dental procedure or in patient with previous infection. 2g PO x once 30-60 minutes before procedure
- H pylori treatment as well.
Amoxicillin/Clavulanate (Augmentin)
- First line treatment for acute otitis media 80-90 mg/kg/day of amox. (make sure to do 14:1 ratio with clavulanate to ensure reduction in diarrhea
- Used to treat bacterial sinusitis
Dicloxacillin
- covers MSSA , not MRSA, no need to renally dose adjust
Use of Pen G Benzathine (Bicillin L-A) and important points
Drug of choice for syphilis (2.4 million units IM x 1 for early stage infections, but if later stage, we sometimes give 1/week injection)
- this MUST be IM, NEVER IV because of the risk of death (it’s a lipid emulsion)
Which penicillin should never be given IV because of it’s risk of death
Penicillin G Benzathine (Bicillin LA)
Which important Penicillins are only Parenteral use
Pen G (IM ONLY, NEVER IV)
Nafcillin (IV/IM) /Oxacillin (IM)
Piperacillin/Tazobactam (Zosyn) - only one that covers psuedomonas and uses extended infusions to maximize the Time > MIC
What are the first generation cephalosporins, their dosage forms and doses
Cefazolin IV/IM: 1-2 grams Q8H (equiv to keflex)
Cephalexin PO 250-500 mg Q6-12H (equiv to cefazolin)
Cefadroxil PO 1-2 grams Q12-24H
What are the 2nd generation cephalosporins, their dosage forms, and their doses
Cefuroxime (Ceftin) PO,IM,IV 250-1500 mg Q8H -12H
Cefotetan (Cefotan) IV/IM 1-2 grams Q12H
Cefaclor PO 250-500 mg Q8H
Cefoxitin IV/IM 1-2 g Q6-8H
Cefprozil PO 250-500 mg Q12-24H
What are the GROUP 1- 3rd generation cephalosporins, their doses, and their dosage forms
Cefdinir -old brand name was “omnicef”, but ppl still use that (PO equivalent of cextriaxone) PO 300 mg Q12H or 600 mg daily
Ceftriaxone IV/IM 1-2 grams Q12-24 hrs
Cefotaxime IV/IM 1-2 grams Q4-12 hrs
Cefditoren PO 200-400 mg Q12H with food
Cefixime (Suprax) PO: 400 mg divided Q12-24 H
Cefpodoxime PO: 100-400 mg Q12H
Ceftibuten: PO: 400 mg daily on an empty stomach
What are the group 2 third generation cephalosporins and their combinations , dose, and dosage form
Ceftazidime (fortaz, tazicef) IV/IM 1-2 grams Q8-12 H
Ceftolozane
Psuedomonas coverage:
Ceftazidime/avibactam (Avycaz) - IV: 2.5 g Q8H
Ceftolozane/tazobactam (Zerbaxa) - IV: 1.5-3 g
What is the 4th generation cephalosporin and what is it’s dosage form and strength
Cefepime IV/IM: 1-2 g Q 8-12 H
Covers pseudomonas
What is the 5th generation cephalosporin and what is it’s dosage form and dose
Ceftaroline fosamil (Teflaro) IV: 600 mg Q12H
Covers MRSA
What is the siderophore cephalosporin and what is it’s function
Cefidericol- it uses the iron transport system to enter gram negative cell wall.
Approved for complicated UTI/pyelonephritis and active against Enterobacter, Klebsiella, Proteus, (PEK) and Pseudomonas and E. coli
What are some contraindications for Ceftriaxone
Hyperbilirubinemic neonates (causes biliary sludging kernicterus)
Concurrent use with calcium containing IV products in neonates < 28 days old
Class effects of Carbapenems
all active against ESBL producing organisms
and pseudomonas (except ertapenem)
cannot be used with penicillin allergy
CNS adverse effects, confusion, seizure risk at high doses or failure to adjust dose in renal dysfx (check if they are on any seizure meds), or with use of imipenem cilastatin. they decrease the serum conc. of valproic acid and poor seizure control
all are IV, and ertapenem has to be diluted in normal saline
SE: diarrhea, rash, DRESS syndrome, bone marrow suppression with prolonged use, increased LFTs
all are hydrophillic, so they can accumulate in renal failure and cause seizure
MONITOR: renal function**,CBC, LFT, sx of anaphylaxis on first dose
what do carbapenems not cover
Because they are cell wall acting agents, they don’t cover atypicals, VRE, MRSA, C diff, or stenotrophomonas
ErtAPenem doesnt cover EAP: pseudomonas, enterococcus, and acinetobacter
common uses for carbapenems
polymicrobial infx (ex: sever diabetic foot infx)
empiric therapy when resistant organisms suspected
ESBL positive infections
Resistant pseudomonas or acinetobacter infx (except ertapenem)
Types of carbapenems
doripenem - never use for any type of pneumonia
Imipenem/Cilastatin (primaxin) - old, combo to prevent drug degredation
Meropenem (meropenem/vaboractam = vabomere)
Ertapenem (Invanz) - dilute with stable NS only; common for Diabetic foot infx
aztreonam
a monobactam
can be used in pts with beta lactam allergy
gram negative coverage including pseudomonas (no gram positive or anaerobic activity)
SE: similar to penicillins, including rash, N/V/D and increased LFTs
beta lactams/aztreonam that cover MRSA
ceftaroline
penicillin SOA
(+)
S. pneumoniae
Viridans group strep
Enterococcus (not VRE)
Gram positive anaerobes
no gram negative
amoxicillins SOA
(+)
S. pneumoniae
Viridans strep.
Enterococcus (not VRE)
Gram pos. anaerobes
(-)
PE - no klebsiella
HNPE - no klebsiella
Oxacillin + Nafcillin SOA
(+)
MSSA/ staph. aureus
S. pneumoniae
Viridians strep.
Enterococcus (not VRE)
unasyn and augmentin SOA
(+)
Staph aureus/MSSA
S. pneumoniae
Viridans strep.
Enterococcus (not VRE)
gram positive anaerobes
(-)
PEK
HNPEK
Bacterioides fragilis
Zosyn and carbapenem (except ertapenam) SOA
BROAD (+ and -)
they don’t cover atypicals or MRSA
ertapenam doesn’t cover PEA (psuedo, enterococcus, or acinetobacter), the rest of the carbapenems cover E fragilis type of enterococcus
all gen ceph’s SOA (cephalexin, cefazolin)
(+)
S. aureaus (MSSA)
S pneumoniae
Viridans Strep.
gram positive anaerobes
(-)
PEK
additional coverages as we increase generations:
2nd generation cephalosporins can additionally cover HNPEK (-) and the only ones that coverbacterioides fragilis (cefuroxime, cefotetan, cefoxitin) cefotetan doesnt cover B fragilis
3rd generation cephs can additionally cover (-) CAPES, but don’t cover B fragilis. (cefotaxime, ceftriaxone).
Ceftazadime is different. it and aztreonam only covers gram negative (PEK, HNPEK, CAPES, psuedomonas)
4th gen (cefepime) covers all of the above except B fragilis (HNPEK, PEK, CAPES, pseudomonas, MSSA , Spneumoniae, V strep.
5th ceftaroline (+)*(MRSA; (-) covers no psuedomonas, doesnt cover providencia or acinetobacter
cephs that cover pseudomonas
cefepime
ceftazadime
ceftolozane
what do we need to make sure to give with the 5th gen ceph combos
ceftolozane/tazobactam
ceftazadime/avibactam
both should be given with metronidazole to ensure proper anaerobic coverage
these can help with MDR pseudomonas or MDR gram negative rods
aminoglycosides
highly toxic to kidneys and ears. concentration dependent abx. not used as much. need monitoring and dose specific considerations. usually used empirically in combo with other things, not alone.
used mostly for gram negatives including pseudomonas. at lower doses can be used for gram positives (staph and enterococci)
traditional dosing (if renal fx is normal)- 1-2.5 mg/kg IV Q8H, monitor using peaks and troughs (draw trough 30 min before 4th dose and peak 30 min after end of 4th dose infusion (usually 1 hr) - trough is what causes toxicity, so we should monitor this < 2 mcg/mL we don’t want trough accumulation; peak should be 5-10 mcg/mL for gent/tobra
extended interval dosing - 4-7 mg/kg IV q24h, we monitor by drawing random level and using nomogram- shortest interval is 24 hrs for normal renal fx. this is better for the sake of toxicity because we can give larger doses less frequently and allows kidneys to rest, also lower cost
gentamicin, tobramycin, amikacin (most active against pseudomonas), streptomycin, plazomicin
gentamicin and streptomycin can be used for synergy in combo with a beta lactam or vanc. to treat gram (+) infections like enteroccocal endocarditis
streptomycin and amikacin can be used as second line agents for mycobacterium
Boxed warnings and regular warnings and SE for Aminoglycosides
nephrotoxicity
ototoxicity
neuromuscular blockade and resp. paralysis
avoid with other neurotoxic/nephrotoxic drugs, CI in pregnancy cause teratogenic
regular warnings:
caution if impaired renal fx, in elderly, and in pts taking nephrotoxic drugs: ampB, cistplatin, polmixins, cyclosporine, loop diuretics, NSAIDS, radiocontrast dye, tacrolimus, vancomycin.** need to know this list!
SE: otoxocity, nephrotoxicity, vestibular toxicity (balance)
what should we monitor in pts on Aminoglycosides
trough (<2 mcg/mL) and peak levels (5-10 mcg/ml)
renal function (urine output)
Renal dose adjustments for patients on traditionally dosed aminoglycosides
crcl
at least 60 ml/min q8h
40-60 ml/min q12h
20-40 ml/min q24 hr
< 20 ml/min - use just one dose, then dose based on levels.
use adjusted body weight when TBW > 120% of IBW. use IBW if normal weight, use ABW if ABW < IBW
hospitals have protocols to guide dose adjustments for aminoglycosides based on the serum concentrations.
drugs that decrease stomach acid can decrease the F of some cephalosporins
separate cefuroxime, cefpodoxime, cefdinir, and cefditoren from short acting antacids. Avoid H2RAs and PPIs
Cephs that cover MRSA
ceftaroline
contraindications of ceftriaxone
never use in hyperbilirubinemic neonates because it causes biliary sludging, and kernicterus
never use with calcium containing IV products in neonates less than 28 days old because of the precipitates it forms with calcium containing IV fluids.
Quinolones
concentration dependent killing (dosed twice daily). inhibit bacterial DNA topoisomerase 1 and 2
- boxed warnings: DC immediately if tendon rupture/achilles tendon (esp. in pts on systemic steroids or organ trasnplant pts > 60 yrs; long lasting peripheral neuropathy, CNS effects (including seizures), use last line
- warnings:
- QT prolongation
- hypo and hyperglycemia
- psychiatric disturbances
- photosensitivity
- avoid use in children and anyone pregnant/breastfeeding because of musculoskeletal effects
- avoid in pts with myasthinia gravis bc it can exacerbate muscle weakness
- caution with CVD, decreased K+/Mg and with other QT prolonging drugs!! (ex: azoles, antipsychotics, macrolides, methadone, antifungals)
- avoid in pts with seizure history or using antiepileptic drugs
- monitor BG in pts with DM
interacts with divalent cations (iron, calcium, magnesium, etc.) separate from phosphate binders too
names: Cipro, levo, moxifloxacin, and gemifloxacin
can be used for travelers diarrhea, Intraabdominal ifnections and pseudomonas needs
Respiratory quinolones
My Good Lungs (moxi, gemi, and levofloxacin)
they are active against S. pneumoniae in pneumonia and atypical bacteria
Moxifloxacin (IV: PO 1:1) is the only quinolone that is not renally adjusted so it should never be used for UTIs
Antipseudomonal quinolones
Levofloxacin IV:PO - 1:1
Ciprofloxacin
Quinolones can increase effects of warfarin, increase effects of sulfonylureas, insulin, and other hypoglycemic drugs
Ciprofloxacin can increase caffeine, theophylline, and tizanidine levels by reducing metabolism
Ciprofloxacin
brand: cipro, ciloxan eye drops, cetraxal, and otiprio ear drops (ear drops can come in combo with steroid)
IV and PO dosing interval varies w/ CrCl
Contraindicated with concurrent use of tizanidine
dont put the oil based suspension in a feeding tube because it adheres to tubing, but you can crush the immediate release tablet and mix with water. hold feedings 1 hour before and 2 hrs after dose.
Levofloxacin (levaquin)
IV and PO. dose adjust if CrCL < 50 to Q48H or decrease dose
Moxifloxacin (Avelox)
Moxeza and Vigamox eye drops
no renal dose adjustments required
QT prolongation risk is the highest
cefotetan has a side chain (NMTT or 1-MTT) that can increase the risk of bleeding or cause a disulfuram like reaction
some cephalosporins can increase INR for pts on warfarin.
monitoring with cephalosporins
renal function, signs of anaphylaxis with first dose, CBC, LFTs
ceftriaxone requires no renal dose adjustment but it reaches CNS penetration at high doses
normal dose IV/IM 1-2 g Q12-24 H
cefazolin and cephalexin are 1st gen cephs that are equivalents
cefazolin IV/IM 1-2 grams Q8H
cephalexin (Keflex) PO: 250-500 mg Q6-12 H
if pt has penicillin allergy, for exam dont give them a cephalosporin unless
they are pediatric patients with acute otitis media and mild penicillin allergy
Common use for cephalexin outpt (PO)
best drug for staph
MSSA skin infections, strep throat
common use for cefuroxime outpt (PO)
acute otitis media
CAP
common use for cefdinir outpt (PO)
acute otitis media
Common use of cefazolin inpt
surgical prophylaxis
equivalent to keflex (cephalexin)
common use of cefotetan and cefoxitin
anaerobic coverage ( B fragilis), GI surgical prophylaxis, cefotetan
Common uses for ceftriaxone and cefotaxime
CAP
meningitis
spontaneous bacterial peritonitis
pyelonephritis
remember: ceftriaxone has no renal dose adjustment and we should never give it to neonates < 28 or pregnant women
Common uses for ceftazadime and cefepime and ceftolozane
pseudomonas
common uses for ceftolozane/tavibactam and ceftazidime/avibactam
MDR gram negative organisms (including pseudomonas)
Common uses for ceftaroline
only beta lactam that is active against MRSA
CAP
skin and soft tissue infections
