Day 3.3 Micro Flashcards
What do penicillins (and cephalosporins) do?
Disrupt the cell wall (so good for gram+, also some gram-)
What is a penicillinase?
Aka Beta-lactamase
Substance md by some bacteria that breaks down penicillin
Sometimes abx can be combined with a penicillinase (beta-lactamase) inhibitor to give them a wider spectrum. What are the inhibitors?
Clavulanic acid
Tazobactam
Sulbactam
Amoxicillin + clavulinic acid = augmenten, used for ear infections in kids
Ampicillin + sulbactam - unacyn
IV med used for surgical infections
What is the toxicity for Ampicillin and amoxicillin (the aminopenicillins)?
HPS rxn
Ampicillin rash in mono pts (EBV)
Pseudomembranous colitis (C. diff)
What are the clinical uses of penicillin?
Gram+:
S. pneumonia, S. pyogenes, Acintomyces, Gp B strep (esp moms in labor)
Gram+ rods: Clostridium, Bacilus, Listeria
Spirochetes: Syphilis (drug of choice)
Gram-neg cocci: Neisseria
How do gram-neg organisms cause resistance to penicillins?
Hydrolysis of Beta-lactam ring by bacterial penicillinases (beta-lactamases) in the periplasmic space. (Can use beta-lactamase inhibitors- clavulanic acid- to prevent this)
How do gram+ organisms cause resistance to penicillins?
They alter the B-lactam targets. (Alter PBPs- penicillin binding proteins)
S. pneumonia and S. aureus especially.
Augmenten
Amoxicillin + clavulanic acid
Used for ear infections in kids
Unasyn
Ampicillin + sulbactam
Used in surgery
Timentin
Ticarciliin + clavulanic acid
Zosyn
Piperacillin + tazobactam
Which drugs cause a disulfiram-like reaction?
Anatabuse (disulfiram) Certain cephalosporins Metronidazole 1st gen sulfonureas Procarbazine (chemo for Hodgkin's)
Treatment for Proteus, E. coli, K. Pnuemonia (UTI bugs)
1st gen cephalosporins- esp cephalexin
When are 1st gen cephalosporins used w/ aminopenicillins?
Prophylaxis is against Viridans in dental procedures
3rd gen cephalosporins provide less gram+ coverage- but can still be used for which gram+ organism?
S. pneumonia
What kind of drug is gentamycin?
Aminoglycoside.
Cephalosporins increase the nephrotoxicity of aminoglycosides like gentamycin.
If a pt has a bad infection and you don’t know what it is, what is a good antimicrobial to use?
Imipenem/cilastin; meropenem.
V broad spectrum, v powerful, beta-lactamase resistant.
Doesn’t work for MRSA tho.
Clinical use for vancomycin
serious gram+ multi-drug resistant organisms- S. aureus (MRSA) and C. diff (pseudomembranous colitis). Can use oral vanc for C. diff bc only need it to go to gut, not systemic.
Also Coagulase-negative endocarditis caused by S. epidermidis (IV drug users)
Which cephalosporin lasts the longest?
Longest half-life = ceftriaxone (3rd gen)
give 1x/day IV or IM
Disulfiram-like rxn
Disulfiram inhibits aldehyde dehydrogenase, so ethanol is not fully metabolized. Aldehyde accumulates and causes flushing, sweating, nausea/vom, headache
Rx for Pseudomonas (Gram-neg rod, aerobic, likes moist env and hospitals)
3rd gen- ceftazidime
4th gen- cefepime
aztreonam
ticarcillin, carbenicillin, piperacillin (ant-pseudomonals)
Aminoglycoside pretender
aztreonam
Clinical use for aztreonam
Klebsiella, E coli, Pseudomonas, Serratia.
For pts who are allergic to penicillin, pts with renal insufficiency who can’t tolerate aminoglycosides
Red man syndrome
Diffuse whole-body flushing caused by vancomycin.
Prophylaxis: anti-histamines, slow infusion of vanc
If otitis media is resistant to amoxicillin, what should you give?
Add clavulanic acid (Augmentin)
or use 3rd gen cefidinir
What increases the nephrotoxicity of aminoglycosides?
Cephalosporins
Rx for syphilis
Penicillin
Rx for gonorrhea
Single dose ceftriaxone
Rx for C. diff
Oral vanc or metronidazole
1st gen cephalosporins
cephalexin
cefazolin
for PEcK
2nd gen ceph
cefprozil
for HEN PEcKS
3rd gen ceph
cefdinir
ceftrixone
4th gen ceph
cefipime
Epiglottitis mgmt
mk pt comfortable and don’t do anything
avoid upsetting child and losing airway
want ability to rapidly intubate
Epiglottitis px
Cherry red Omega sign Lean fwd to straighten airway Drooling bc can't swallow spit Thumb sign on xray d/t edema
Fitz-Hugh-Curtis syndrome
PID (from neisseria gonorrhea) that starts in lower genital tract but ascends to upper tract, ultimately affecting the liver capsule
Waterhouse-Friedrichson syndrome
Adrenal hemorrhage d/t meningiococcemia.
Bleeding causes adrenal insufficiency- hypotension, electrolyte imbalance, DIC
How do you prophylax close contacts of Neisseria meningococci?
Rifampin
What kind of proteases does Neisseria produce?
IgA proteases
Cause of epiglottitis
H. influenzae (Gram-neg cocco-baciliary rod)
What kind of protease does H. influenzae produce?
IgA protease
Hemophilus ducreyi
Painful genital ulcer- chancroid
Atypical pneumonia
Diffuse, lighter (NOT lobar like regular pneumonia). More interstitial areas.
Caused by Legionella, Chlamydia, Mycoplasma.
Rx for atypical pneumonia
Macrolides-
Erythromycin
Azithomycin
Zithromax
Pneumonia in cystic fibrosis is caused by which organism?
Pseudomonas aeruginosa
Drug use leading to endocarditis- which bacteria?
Gram-pos S. epidermidis
Gram-neg Pseudomonas aeruginosa
Bilateral Bell’s Palsy (facial nerve paralysis)- 2 causes
Lyme dz
Guillan-Barre syndrome
Most common cause of Gram-neg sepsis?
E.coli
2nd- Klebsiella
Septic arthritis in young adult
Neisseria gonorrhea
Cat scratch
Bartonella henselae
Dog/cat bite
Pasturella multocida
Cat feces
Toxoplasmosis
avoid if prego
Puppy feces
Yersinia enterocolitica
Animal urine
Leptospira
Rat bites
Spirillum minus
Proteus (mirabilis, vulgaris)
Motile, no distinct colonies can be grown.
Common cause of UTI
Carries urease:
urea –> NH3 + CO2 –> ammonium/magnesium/phosphate stones –> staghorn caliculi
Osteomyelitis in sickle cell pts
Salmonella
Neisseria gonorrhea
urethritis, cervicitis, PID, epididymitis (same as chylamydia)
Most common cause of septic arthritis in young sex-active pts
Opthalmia neonatorum-vertical txmsn, sticky eye discharge, may cause blindness
How is opthalmia neonatorum prevented?
Erythomycin eye drops- give to everyone.
prevents n. gonorrhea vertical txmsn
Pseudomonas aeruginosa causes…
pneumonia (CF, immunocompromised) burn, wound infections corneal infections (contact lens) osteomyelitis in DM, IV drug abusers sepsis (v high mortality) extermal otitis (elderly, DM) hot tub folliculitis, endocarditis (IV-DA) UTI (foley)
What are the enterobacteraiceae?
Family of gram-neg rods: E. coli Salmonella Shigella Klebsiella Enterobacter Serratia Proteus
All have O (somatic) Ag K (capsular) Ag is related to virulance H (flagellar) Ag is on motile species All ferment glucose All are oxidase negative.
What does E.coli cause?
diarrhea
UTI
neonatal meningitis/pneumonia/sepsis
4 types of E. coli
EIEC - invades intestinal mucosa
EHEC, ETEC, EPEC - do not invade
EIEC
enteroinvasive E.coli
invades intestinal wall, so get fever and bloody diarrhea.
has shiga-like toxin (verotoxin) which inhibits 60S ribosome
ETEC
traveler's diarrhea Rx: TMP-SMX or fluroquinolones (cipro) similar to cholera- rice water diarrhea no intestinal wall invastion- so no fever, bloody labile toxin and stabile toxin
EHEC
O157:H7 hamburger meat get HUS shiga-like toxin. dysentery- bloody diarrhea does NOT ferment sorbitol like other E.coli
What is HUS
Hemolytic-uremic syndrome. Triad: 1. Anemia (hemolysis) 2. Renal failure (uremia = high lvl of nitrogen waste in blood) 3. Thrombocytopenia (low plt)
EPEC
no toxin
adheres to apical surf and flattens villi, so prevents absorption
Diarrhea usu in daycare kids
Salmonella
most common cause of food-assocd diarrhea in developed countries (poultry, eggs, reptiles)
S. enterica, S. enteritidis
Avoid Abx!! bc can prolong the carrier state of salmonella in GI tract infections
What causes typhoid fever?
Salmonella typhi
Shingella
Bacterial dysentery can be caused by Shigella flexneri, sonnei, dystenteriae
Shigella flexneri
Assoc w Reiter’s Reactive arthritis (can’t see, pee, climb a tree)
Campylobacter jejuni
Oxidase+ comma-shaped gram-neg grows in 42C (hot CAMPfire) mjr cause of diarrhea in kids fecal-oral poultry, meat, unpasterized milk precursor to Guillan-Barre
What gram-neg has aerosol txmsn, not person-person
Legionella pneumophilia
What enz to obligate anaerobes lack?
Catalase
Superoxide dismutase
so susceptible to oxidate dmg
Clostridium, Bacteroides, Acintomyces
Osteomyelitis in DM
pseudomonas
Aspiration pneumonia (alcoholic)
Klebsiella pneumonia
Common cause UTI and pneumonia
Klebsiella pneumonia
Treatment for gonorrhea?
Single dose ceftriaxone
What drugs inhibit protein synth?
30S:
Aminoglycosides
Tetracycline
50S: Chloramphenicol, Clindamycin Erythromycin Lincomycin Linezolid
Discoloration of teeth and inhibition of bone growth in kids
Tetracyclines
Drugs with ototoxicity and nephrotoxicity
Aminoglycosides
Vancomycin
Loop duretics
Cisplatin (chemo)
Gray baby
Gray man
Red man
Gray baby = chloramphenicol
Gray man = amiodarone (anti-arrhythmia)
Red man = vancomycin
What drugs should be avoided in pts with sulfa allergy
Sulfonamides TMP-SMX Sulfasalazine Sulfonylureas Sumatriptan Acetazolamide (diurectic- CA inhibitor) Furosemide Thiazide Probenecid (gouty arthritis) Celecoxib (COX-2 inhibitor)
Most common causes of UTI
E.coli #1
Proteus, Klebsiella, Pneumonia
Abx that treat UTI
Aminopenicillins
Cephalosporins
Nitrofurantoin
Sulfonamides
Drugs w photosensitive rxns
SAT for a photo:
Sulfonamides
Amiodarone (anti-arrhythmic)
Tetracyclines
Drugs that cause Stevens-Johnson syndrome
Penecillins
Sulfa Drugs
Seizure Drugs- ethosuxamide, lamtrigine, carbamazepine, phenobarbital, phenytoin
Allopurinol (for gout)
Drugs used for Anaerobic infections
Metronidazole
Clindamycin
Imipenem/cilastatin
Meropenem
Drugs that are used for Pseudomonas
polymyxins fluroquinolones cefepime aztreonam (aminoglycoside pretender) aminoglycosides extended-spectrum penicillins (ticarcillin, carbemicillin, piperacillin)
