Download Anti-biotics

Anti-biotics
1.
B-lactams
A.
Ampicillin, amoxicillin : extends the spectrum of penicillin G to some gram-negative rods
i.
High rates of resistance have lessened the value of ampicillin and amoxicillin as empirical
therapy in some situations. For example, >80% of isolates of E. coli and P. mirabilis are
resistant in many hospitals, as are
B.
30% of isolates of H. influenzae;
penicillinase-resistant penicillins(methicillin, oxacillin) : drugs of choice for systemic or deep
staphylococcal infections
i.
on average,
40% of S. aureus isolates and >70% of coagulase-negative staphylococcal
isolates acquired in U.S. hospitals are resistant to these agents
C.
antipseudomonal penicillins(Tazocin-4.5g tid mix c 5dw 100cc, NS에 mix해도 됨. Lactatedringer’s와는 섞이면 안됨. )
i.
AG should generally be added to tazocin for Tx. Of serius infections caused by
pseudomonas aeruginosa or for nosocomial pneumonia
st
D.
1 cepha : cefazolin
E.
2nd cepha : cefoxitin, cefotetan
F.
3rd cepha :
i.
Ceftriaxone :
1.
has a long serum half-life(2g#1),
2.
high serum and CSF levels (with inflammation). -> drugs of choice for empirical
therapy for bacterial meningitis (except that caused by Listeria and by highly
penicillin-resistant pneumococcal strains)
3.
drugs of choice for nonpseudomonal hospital-acquired pneumonia.
ii.
cefotaxime
iii.
ceftazidime : anti-pseudomonal activity
G.
4th cepha : cefepime(maxipime 2g#2) - anti-pseudomonal activity
H.
Carbapenems : excellent activity in vitro against virtually all bacterial pathogens except
Stenotrophomonas, methicillin-resistant staphylococci, and E. faecium
i.
Prepenem(0.5g qid)
1.
imipenem + cilastatin(renal dipeptidase inhibitor)
2.
Imipenem has dose-related central nervous system side effects that are less
frequent with meropenem
ii.
Meropen(0.5~1g tid)
1.
activity vs aerobic gram(-) slightly higher than imipenem.
2.
activity vs staphylo & strepto slightly lower
3.
vs anaerobe : equal to imipenem
4.
I.
biliary excretion : 3-300% (imipenem:minimal)
aztreonam(azactam)
i.
spectrum limited to gram-negative enteric bacilli. It has no activity against any grampositive or anaerobic bacterium. Its gram-negative spectrum is similar to that of
ceftazidime, with equally good activity against Pseudomonas. Aztreonam's primary
advantages are its theoretical ability to preserve the normal gram-positive and anaerobic
flora and the lack of cross-reactive immediate hypersensitivity in patients who have had
this type of reaction to other
2.
-lactam antibiotics.
glycopeptide
A.
vancomycin
i.
Vancomycin serves as second-line therapy for most gram-positive bacterial infections
but is the drug of choice for infections caused by methicillin-resistant staphylococci or
Corynebacterium jeikeium and for serious infections in penicillin-allergic patients.
ii.
Given orally (a route by which it is not absorbed), vancomycin can be used to treat
antibiotic-associated pseudomembranous colitis caused by C. difficile in patients who
have failed to respond to metronidazole
3.
Aminoglycosides
A.
activity limited to gram-negative bacteria and staphylococci, no activity against anaerobic
bacteria and are not effective in environments that are acidic or have a low oxygen tension
B.
synergistically bactericidal in combination with a cell wall-active agent
C.
renal and otic toxicity,
D.
their diminished activity at certain sites of infection (e.g., abscesses and the central nervous
system),
4.
Macrolides and Ketolides
A.
drug of choice for infections due to Legionella, Campylobacter, and Mycoplasma
B.
Clarithromycin and azithromycin have an antibacterial spectrum similar to that of erythromycin
in vitro. However, azithromycin has greater activity against Chlamydia.
5.
lincosamide
A.
6.
7.
clindamycin(fullgram 600mg tid)
i.
activity against most gram-positive and gram-negative strict anaerobes
ii.
pseudomembranous colitis, the major serious side effect of this drug.
SULFONAMIDES AND TRIMETHOPRIM
A.
For nosocomial infections due to Stenotrophomonas, TMP-SMX is the drug of choice.
B.
IV = PO
C.
PCP
FLUOROQUINOLONES
A.
ciprofloxacin - the oral agents with greatest activity against P. aeruginosa; (citopcin 400mg#2
IVF, 1000mg#2 PO)
B.
C.
the newer quinolones have an expanded spectrum of activity against gram-positive cocci
i.
levofloxacine(cravit 250mg-750mg qd)
ii.
gatifloxacine(gatiflo 400mg IV, PO qd)
iii.
moxifloxacine(avelox 400mg #1 IVF)
almagel, MgO, ulcermin, bismuth, oral iron, oral calcium can markedly impair absorption of oral
Quinolones
8.
metronidazole (1500mg#3 IVF)
A.
spectrum limited to anaerobic bacteria, especially gram-negative species (e.g., Bacteroides
spp.).
B.
Because of its spectrum and its ability to penetrate into the area of infection, metronidazole is
one of the drugs of choice for the treatment of any abscess in which the involvement of
obligate anaerobes is suspected (e.g., lung, brain, or intraabdominal abscesses). Other
antibacterial agents should be used in combination with metronidazole if facultative and
aerobic pathogens are also thought to be involved. Metronidazole is the drug of choice for the
treatment of bacterial vaginosis and antibiotic-associated pseudomembranous colitis
9.
linezolid
A.
spectrum limited to gram-positive bacteria
B.
active against vancomycin-resistant enterococci (both E. faecium and E. faecalis) and is one
of the drugs of choice for treating infections due to these organisms. However, since this drug
has only bacteriostatic activity, it has limited utility in treating complicated S. aureus
infections
MECHANISMS OF ACTION
INHIBITION OF CELL-WALL SYNTHESIS : GLYCOPEPTIDES,
-LACTAM
INHIBITION OF PROTEIN SYNTHESIS : AMINOGLYCOSIDES, MACROLIDE , LINEZOLID
INHIBITION OF BACTERIAL METABOLISM : TRIMETHOPRIM/SULFAMETHOXAZOLE
INHIBITION
OF
NUCLEIC
ACID
METRONIDAZOLE
1. CAP(ATS-guideline)
Pseudomonas를 cover? ICU?
SYNTHESIS
OR
ACTIVITY
:
QUINOLONE,
RIFAMPIN.
the need for ICU admission could be defined by using a rule that required the presence of either
-
two of three minor criteria (systolic BP < 90 mm Hg, multilobar disease, PaO2/FIO2 ratio < 250) or
-
one of two major criteria (need for mechanical ventilation or septic shock).
-
With this rule the sensitivity was 78%, the specificity was 94%, the positive predictive value was
75%, and the negative predictive value was 95% (48).
*anti pseudomonal agent : cefobactam, maxipime, tazocin, meropen, prepenem, cefazime, azactam
2. HAP
Onset? MDR risk?
3. PCP
-steroid indication(D>35, PaO2<70)
-U-prin 4T tid – total 21days
-solondo 40mg bid x 5 days, then 40mg qd x 5 days, then 20mg qd x 11 days
-Pts with PCP or CD4<200 -> prophylaxis for life
4. liver abscess
- metro + cefpiran + AG
5. biliary sepsis
- tazocin or ubacillin + AG + metro, if life threatening->prepenem
6. UTI
- acute uncomplicated cystitis in women : citopcin PO x 3days
- UTIs in men : citopcin PO x 7 days, urologic study:treatment fails, recurrent
infection, APN
- APN : mild – outpatient
Severe(N/V, pregnant) – IV 3rd cepha, citopcin
Do not respond to Tx. Withing 48h -> search for renal abscess or calculi
7. PD peritonitis - Cefazolin + ceftazidime
Cefazolin(loading dose:500mg/L, maintenance:125mg/L)
Ceftazidime(loading dose:250mg/L, maintenance:125mg/L)
8. neutropenic fever
Inclusion of vancomycin in initial empirical therapy may be prudent for selected patients with the following
clinical findings:
(1) clinically suspected serious catheter-related infections (e.g., bacteremia,cellulitis)
(2) known colonization with penicillin- and cephalosporin-resistant pneumococci or methicillin-resistant
S.aureus
(3) positive results of blood culture for gram-positive bacteria before final identification and susceptibility
testing,
(4) hypotension or other evidence of cardiovascular impairment