Lecture 1 Flashcards
semisynthetics
abx which have been chemically altered (eg. Penicillin V)
synthetics
abx that are completely man-made (eg. cephalosporin)
spectrum
describes “breadth of activity” of abx
normal flora
humans are colonized with many species of org’s soon after birth, these org’s usually DONT cause disease (symbiotic relationship)
may prevent overgrowth of pathogens
cardinal signs of local infection
redness (rubor), swelling (tumor), heat (color), pain (dolor
symptoms of systemic infection
leukocytosis (inc WBC), fever (>101F), altered structure or loss of function, pure cultures of pathogens from infn site
pathogen
org with inc ability to cause infn (e.g.. strep pneumonia, staph aureus, etc)
virulence
microbial factors that inc likelihood of infn (eg. adhesions, toxins, etc)
high virulence - few org –> infn
low virulence - many org’s –> infn
antimicrobials vs abx
antimicrobials are broader, includes elements and may be anti-vitals, anti-fungals, etc
abx are found in nature and are equivalent to antibacterials
bacteriostatic
inhibits bacterial growth allowing the body’s immune system to act
bacteriocidal
results in bacterial cell death by cell wall lysis, altered memb permeability, etc
narrow spectrum abx
preferred, minimizes the development of resistance
natural resistance
native to an org
acquired resistance
usually associated with abx use, develops after exposure
can occur if pt does not complete their course of therapy
prophylactic abx
used to prevent infn (eg. peri-sx abx is MC, others are heart valve dx, neutropenia, recurrent UTIs and transplant recipients)
Penicillin
inhibits GRAM + CELL WALL SYN
allows inc water to go into cell causing lysis and death (bacteriocidal)
resistance to this medication by penicillinase/B-lactamase has been around the longest
time-dependent killing
anaphylaxis: 0.2% of 10,000 courses
fatality rate: 0.001% in 100,000 courses
Penicillinase Inhibitors
Clavulanic acid (Augmentin is the only PI that is PO), Tazobactam, Sulbactam and Avibactam (newest)
Cephalosporin xxx
structurally related to PCN small amount of cross-sensitization with PCN allergy pt's 1st gen: mainly gram + 2nd and 3rd gen: less gram +, inc gram - 4th gen: best gram -
Macrolides
inhibits PROTEIN SYN, static in usual dose and cidal in higher dose
eg. erythromycin, clarithromycin and azithromycin xxx
side effects of GI upset, cramping and diarrhea
Tetracyclines
1st broad spectrum abx, inhibits PROTEIN SYN
SE’s: photosensitivity, stains developing teeth
can bind cations (antacids and milk) inhibiting absorption xxx
avoid if <8 yo or preg xxx
Aminoglycosides
inhibits PROTEIN SYN (static or cidal depending on dose) used for gram - infn used with PCN/cephalosporins exhibit post-abx effect (PAE) renally eliminated SE: nephrology and oto toxicity poor CNS penetration
quinolones/fluoroquinolones
broad spectrum, inhibits BACTERIAL DNA SYN (cidal)
good oral abs (PO and IV)
renally eliminated (except Moxi- which is hepatic)
good tissue penetration
SE: inhibit cartilage syn, achilles tendon rupture, skin rash, antacids inhibit abs
chloramphenicol xxx
broad spectrum, limiting toxicity is BM suppression
little use, reserved for bad pt’s in ICU who are resistance to many
Aztreonam/Azactam xxx
used in pt’s with PCN allergy
Vancomycin/Vancocin xxx
used for MRSA and C diff from other broad spectrums, poor oral abs
Metronidazole/Flagyl xxx
used for anaerobic/protozoal infn
Sulfonamides
not true abx, bacteriostatic or cidal dep on dose
inhibits folate son required for microorganism growth
UTIs are major use xxx
used in combo with trimethoprim IV/PO (TMP/SMX) xxx
urinary antiseptics
minimal [] in blood/tissue, commonly used for UTIs
e.g. Nitrofurantoin (Furadantin, Macrodantin, Macrobid) - dose dep, taken orally, pulmonary toxicity with long use in elderly, may discolor urine to dark, contraindicated for CrCl <60 (won’t work, but will not harm) xxx
TB tx
first line ex’s are most effective and least toxic
isoniazid (INH), rifampin (RIF), pyrazinamide (PZA), ethambutol (ETH)
used in combo to prevent resistance
systemic antifungals xxx
flucanozole (diflucan) - IV/PO, old and cheap
HIV tx target - reverse transcriptase
nucleoside reversal transcriptase inhibitors (NRTIs) and non-nucleoside RTIs (NNRTIs)
HIV tx target - Protease
protease inhibitors (PIs)
HIV tx target - Fusion inhibitors
Newest category
significant bacteriuria
numbers of bacteria in voided urine that exceed numbers commonly seen due to contamination of urethra
cystitis
term to describe the syndrome involving dysuria, freq, urgency, and occasionally suprapubic tenderness
uncomplicated UTI
infection in a structurally and neurologically normal urinary tract
complicated UTI
infection in a urinary tract with abnormalities (men, preg women, kids)
relapse vs reinfection
relapse is recurrence of bacteriuria with the SAME org, while reinfection is recurrence with a DIFF org
symptoms of UTIs
in adults: dysuria, inc freq/urgency, maybe flank pain, suprapubic heaviness/pain
in elderly: often asymptomatic
Diagnostic techniques of UTIs
urine microscopic exam, dipstick leukocyte esterase, dipstick urine nitrite, urine culture (GOLD STANDARD)
dipstick leukocyte esterase
sensitive to 10 WBC/mm, these enzymes are normally intracellular but once WBCs move into urine they lyse releasing the enzymes
distick urine nitrite
false - for bacteria < 100-1000
false + is rare
gram - org use nitrate and covert to nitrite so this can be measured (high is abnormal)
significant bacteriuria
> 10^5 bacteria/mL in asymptomatic patients on 2 consecutive specimens
antimicrobial resistance
sig inc over last decade, most significant for TMP/SMX, before 1990 E coli resistance was <5%
data suggests inc clinical failures
nitrofurantoin
renewed interest secondary to inc resistance
less active than T/S and FQ
Fosfomycin
long half life, used for non adherent pt’s
single dose tx of cystitis, inferior to 1st line agents though mainly for pt’s susceptible to E coli and E faecalis
