Kháng sinh trong viêm phổi , ĐH Y DƯỢC TP HCM

ANTIBIOTIC FOR
PNEUMONIA
PGS.TS.BS PHAN HUU NGUYET DIEM


Definition of Antibiotics



An Antibiotic is a compound or substance that
kills or slows down the growth of bacteria.
Accordingly, many antibacterial compounds are
classified on the basis of chemical/biosynthetic
origin into natural, semisynthetic, and
synthetic. Another classification system is
based on biological activity:bactericidal agents
kill bacteria, and bacteriostatic agents slow
down or stall bacterial growth.




Classification of Antibiotics
Mechanism of Action


Inhibitors of Cell Wall Synthesis


Beta Lactam Antibiotics
 Penicillins

 Cephalosporins
 Carbapenems
 Monobactams


Penicillines







a group of antibiotics derived from Penicillium
fungi.
Inhibits bacterial cell wall synthesis by
binding and inactivating proteins (penicillin
binding proteins) present in the bacterial cell
wall.
Poor CSF penetration, but can occur if there is
menengial inflammation.
Renal excretion
Side effects: hypersensitivity, nephritis,
neruotoxicity, platelet dysfunction


Penicillines
Penicillin G, Penicillin V, Procain PNC, Extencilline


Gram positive cocci & rods
•
•
•
•
•



Gram positive anaerobes
•
•
•
•



Streptococcus Grp A & B
Streptococcus viridans
Enterococcus
Listeria monocytogenes
Actinomyces
Peptostreptococcus
Clostridium tetani
Clostridium perfringens
Clostridium botulinum

Gram negative cocci

• Neisseria meningitidis

• Pasteurella multocida



Spirochetes

• Treponema pallidum
• Leptospirosis


Penicillines


Antipseudomonal Penicillins
 Carbenicillin
 Ticarcillin +/- clavulanate
 Piperacillin +/- tazobactam


Gram (-) enteric rods:
• Enterobacter species
• E.coli
• Proteus



Other Gr (-) bacilli:
• H.influenza
• Pseudomonas aeruginosa

Aminopenicillins
 Amoxicillin +/- clavulanate
 Ampicillin +/- sulbactam


Gram (+) bacilli:
• Listeria monocytogenes



Gram (-) enteric rods:
• E.coli
• Proteus
• Salmonella typhi



Other Gram (-) bacilli:
• H.influenza


Antistaphylococcal Penicillins
 Methicillin
 Nafcillin
 Oxacillin
 Dicloxacillin


Cephalosporins

Structurally similar to penicillins

Resistant to Penicillinases

Therapeutic concentration in many
tissues.

Renal Excretion

Side Effects: hypersensitivity



C1

C2

C3

C4

Antibiotics

Cephalexine
Cephalothin
Cephazoline
Cephadroxii

Cefuroxime
Cefamandol

Cefoxitine
Cefotetan
Cefaclor

Cefotaxime
Ceftriaxone
Cefixime
Ceftazidime

Cefepime
Cefpirome

Spetrum

Cooci Gr (+) Bacille Gr(-) Bacille Gr(-) Gr (-) multiresistances
Pneumo
Cooci Gr (+) Pseudo
Bacille Gr(-)

CSF

(-)

Gr (+) < C1
(-)

(+)

(+)

Monobactams
 Aztreonam









Monocyclic beta-lactam ring & relatively resistant to
most beta-lactamases
active against aerobic Gram negative rods, P.
aeruginosa, , but have no activity against gram
positive bacteria or anaerobes.
Penetrates well into the CSF
Not absorbed orally
Side effects: GI, occasional skin rashes
no cross-reactivity with PCNs


Carbapenems
 Meropenem/Imipenem










broad spectrum
active against MRSA
given IV
penetrates CSF
renal metabolism and excretion
addition of cilastin (Imipenem - inhibitor of
dehydropeptidase I )
Side effects: GI upset, eosinophilia, neutropenia,
lowering of seizure threshold


Vancomycin




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Glycopeptide
Inhibits cell wall synthesis by inhibiting
peptidoglycan synthetase
Most gram-positive bacteria, MRSA
Useful for beta lactam resistant infections
Synergistic action with aminoglycosides against

susceptible gram positives
Slow CSF penetration unless there is meningeal
inflammation
Side effects: Hypotension & “Red Man
Syndrome” if given i.v. in less than 1 hour,
nephrotoxicity, ototoxicity…


Cell Membrane Active Agents
 Polymyxins

o A group of basic peptides active against
gram-negative bacteria.
• Serious infections caused by P. aeruginosa, H.
influenzae, E. coli, A. aerogenes & K. pneumoniae
when other drugs are contraindicated
• Ocular infections (bacterial conjunctivitis ophthalmic drops)
• Meningitis

o Side Effects: Nephrotoxic & Neurotoxic


Protein Synthesis Inhibitors


Tetracyclines






Aminoglycosides






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


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Amikacin
Gentamycin
Neomycin
Streptomycin
Tobramycin

Macrolides




Tetracycline
Doxycycline
Minocycline

Azithromycin
Clarithromycin
Erythromycin

Chloramphenicol
Clindamycin


Tetracyclines





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

Bind to 30S ribosomal subunit.
Broad spectrum bacteriostatic & generally 2nd line drugs
of choice.
Susceptible bacteria include: Streptococcal pneumoniae,
Bacillus anthracis, Clostridium tetani, Brucella,
Helicobacter pylori, Actinomyces, Rickettsia, Chlamydia
and Mycoplasma.
Doxycycline: Malaria prophylaxis, Bacillus anthracis
Minocycline: Acne
Not recommended for pregnant women, infants and
children 8 years or younger.

Side Effects: Staining of teeth, retardation of bone
growth, GI toxicity, Photosensitivity…


Aminoglycosides





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Streptomycin
Neomycin
Gentamicin
Tobramycin
Amikacin
Netilmicin


Aminoglycosides







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Aerobic Gram negative bacilli: Klebsiella, Serratia,
Proteus, Pseudomonas, tularemia, plague, brucellosis….
Effective against Aerobic Gram positive cocci:
Staphylococcus, Group B Streptococcus, viridans
streptococci, Enterococcus
Mycobacteria – tuberculosis
N. gonorrhoeae
Not effective against anaerobes
AGs are not recommended as monotherapy for severe
infections, but must be combined with another agent
Used in combination with vancomycin or a penicillin for
enterococcal endocarditis, and for treatment of
tuberculosis.


Aminoglycosides
Exp: CSF


Macrolides
 Erythromycin
 Clarithromycin
 Azithromycin



Bacteriostatic
Spectrum: Staph., S. pyogenes and S.
pneumoniae, Legionella and H.pylori.
Chlamydia, Mycoplasma (Clinically useful in

penicillin hypersensitive patients).