ribosomal 50S subunit, which prevents translocation of
Antibiotic Summary
folic acid production and thus inhibits nucleic acid
polypeptide chain
synthesis and bacterial growth • SMX competes with paraaminobenzoic acid for
Clinical Use
dihydropteroate synthase to prevent
• Mycoplasma,Legionella,Chlamydia,Treponema,
folic acid production and thus inhibit nucleic acid
Helicobacterpylori
ANTIBACTERIALS
broad spectrum activity against enteric Gram
(streptococcal infections in patients allergic to penicillin)
negatives, less Gram positive
• first line therapy for community-acquired pneumonia as
coverage than 1st generation
CELL WALL SYNTHESIS INHIBITORS (BACTERICIDAL)
ceftazidime should be used if
Pseudomonas
Mechanism of Action
• 4th generation
Gram positive cocci (MRSA and
G-ve
S. pneumoniae )
Ana.
Clinical Use
(not B. fragilis ), Neisseria , and T. pallidum (syphilis)
• broadest spectrum of activity against anaerobes, Gram positives (except Enterococcusfaecium
• isoxazoyl penicillin (narrow spectrum, penicillinase
Gram negatives, including
resistant))
• always administered with cilastin (inhibitor of renal
Mechanism of action
Enterococci, some Gram negatives
Clinical Use
G+ve
e.g. piperacillin,carbenicillin,ticarcillin G+ve
effective against Gram positives,
Gram negatives (e.g. Enterobacter ) , and anaerobes
Ana.
• requires oxygen for uptake, t herefore, ineffective against
anaerobes
(e.g.Tetracycline, Doxycycline)
for antibiotic-associated pseudomembranous
Mechanism of Action
colitis ( C. difficile )
• inhibit protein synthesis by binding to t he 30S ribosomal
G+ve
G-ve
• inhibits bacterial protein synthesis by inhibiting
1-3
Clinical Use • Gram positive cocci, many Gram negative bacilli, most Mycobacterium species • always used in combination to reduce resistance • prophylaxis against meningococcus
subunit, thereby blocking amino acid linked tRNA from binding to the A site of the ribosome
PROTEIN SYNTHESIS INHIBITORS
Gram positive cocci (except MRSA and
, Borreliaburgdoferi
• doxycycline used for malaria prophylaxis and treatment • tetracycline used to treat acne
Mechanism of Action
)
damage the microbial DNA • GI upset, hepatotoxicity
Clinical Use
from associating with peptidyl transferase
• Fanconi’s syndrome
• anaerobic bacteria (first line therapy for
Clinical Use
negative coverage than 1st
(contraindicated in pregnancy, neonates, children)
• 2nd line treatment for meningitis ( H. influenzae,
generation ( H. influenzae, E. coli , Klebsiella,Proteus
)
FOLIC ACID METABOLISM INHIBITORS (BACTERIOSTATIC)
MACROLIDES
ceftazidimeIV/IM ceftazidime IV/IM
• used in combination with omeprazole and clarithromycin in patients with penicillin allergy for triple therapy against H. pylori
G+ve
TRIMETHOPRIM-SULFAMETHO TRIMETHOPRIM-SULFAMETHOXAZOLE XAZOLE (TMP-SMX)
Mechanism of Action
(Bactrim) Mechanism of Action
• inhibit protein synthesis by binding to the P site of the
• TMP inhibits dihydrofolate reductase which prevents
e.g. cefotaxime IV/IM, cefotaxime IV/IM, ceftriaxone IV/IM,
pseudomembranouscolitis) • several protozoan parasites (Trichomoniasis, s, amebiasis, giardiasis)
N. meningitides, S. pneumoniae )
(e.g. Erythromycin,Clarithromycin, Azithromycin)
• forms toxic metabolites in the bacterial cell which
50S subunit, which prevents the aminoacyl end of tRNA
• discolors teeth and inhibits bone growth in children
less Gram positive activity but more Gram
Ana.
Mechanism of Action
Side-effects
• inhibits protein synthesis by binding to the ribosomal
axetil po (Ceftin), Cefotetan po (Cefotan), Cefoxitime
METRONIDAZOLE
(Lyme disease)
CHLORAMPHENICOL
Enterococci), Gram negative bacilli
DNA COMPLEX DAMAGING AGENTS (BACTERICIDAL)
Clinical Use • Chlamydia,Mycoplasma,Rickettsia
VIA 50S RIBOSOME (BACTERIOSTATIC)
(Keflex™)
intra-abdominal and pelvic infections
TETRACYCLINES
oral formulation is 2nd line treatment
• 3rd generation G-ve
Mechanism of action DNA-dependent RNA polymerase
VIA 30S RIBOSOME (BACTERIOSTATIC)
cefotetan has anaerobic activity and is used in
G+ve
infections
against the penicillinase producing organisms
e.g. cefuroxime IV/IM (Kefurox or Zinnat); Zinnat ); cefuroxime
G-ve
Pseudomonasaeruginosa
enhance spectrum of activity especially
• 2nd generation
DNA-DEPENDENT RNA POLYMERASE INHIBITORS (BACTERICIDAL)
RIFAMPIN
(e.g. anaphylaxis, exfoliative dermatitis, vasculitis, or severe urticaria)
with joint or line infections
combine tazobactam with piperacillin to
moxifloxacin and gatifloxacin have some anaerobiccoverage
• primarily Gram negative aerobes and mycobacteria
S. epidermidis ) in patients with prosthetic valves
(e.g. Bacteroidesfragilis )
(mainly E. coli , Klebsiella,P.mirabilis
G+ve
• inhibit protein synthesis initiation by binding to the 30S
• tobramycin used for
coagulase-negative Staphylococcus (e.g.
e.g. Cefazolin IV/IM Cefazolin IV/IM (Ancef™ or Kefzol); Kefzol); cephalexin po
G-ve
Mechanism of Action
pneumonia as an outpatient
Clinical Use
• 1st generation
MRSA infection
Pseudomonas ,
Clinical Use
G+ve
first line therapy for community acquired
true major penicillin allergic patients
CEPHALOSPORINS
1-1
Mycoplasma )
ribosomal subunit, thereby causing misreading of mRNA
• only active against Gram positive organisms
• ureidopenicillins (broad spectrum, penicillinase sensitive)
respiratory pathogens ( Legionella,Chlamydia,
VIA 30S RIBOSOME (BACTERICIDAL)
G-ve
resulting in loss of cell wall integrity and osmotic rupture
complicated cystitis in adults • levofloxacin, moxifloxacin, gatifloxacin useful against
(e.g.Vancomycin)
of the bacterium
• enteric Gram negative bacilli of urinary and GI tracts, limited Gram positive coverage ( 6 with levo, moxi, gati)
use if Pseudomonas suspected
• Streptococci (bactericidal)
AMINOGLYCOSIDES
ampicillin combined with gentamicin first line
increase activity vs. beta-lactamase producers)
(basteriostatic): use in VRE
(e.g. Gentamicin, Tobramycin,Amikacin,Streptomycin,Neomycin)
asymptomatic UTI in pregnant women
combine with clavulanic acid (penicillinase
Ana.
• blocks cell wall peptidoglycan polymerization (synthesis)
amoxicillin first line therapy for acute cystitis or
• Enterococci,Staphylococci
GLYCOPEPTIDES
inhibitor e.g. Augmentin ) Augmentin ) to enhance spectrum (i.e.
G-ve
G-ve
Clinical Use
• ciprofloxacin first line therapy for uncomplicated and
Clinical Use
tubules
therapy for pyelonephritis
dihydropeptidase I) to decrease inactivation in renal
effective against most Gram positives including
G+ve
effective against Staphylococci and some
e.g. ampicillin,amoxicillin
G-ve
and MRSA), and
• imipenem drug of choice for drug-resistant Enterobacter
Streptococci; drug of choice for
funtional 70S initiation complex
e.g. methicillin, cloxacillin, oxacillin, nafcillin
penicillin-resistant S. aureus (PRSA) • aminopenicillins (broad spectrum, penicillinase sensitive)
G+ve
• binds 23S ribosomal area of the 50S s ubunit, prevents
P.aeruginosa
G-ve
gyrase to block DNA replication
Mechanism of Action
(e.g.Imipenem,Meropenem)
effective against Streptococci, most anaerobes
G+ve
ofloxacin, gatifloxacin, nalidixic acid Mechanism of Action
LINEZOLID
CARBAPENEMS
e.g. penicillin G (IV G (IV or IM), penicillinV (PO) V (PO)
• e.g. ciprofloxacin,levofloxacin, ciprofloxacin, levofloxacin,moxifloxacin,norfloxacin,
• prevents supercoiling of nucleic acids by inhibiting DNA
infections (pneumonia, bacteremia)
• benzyl penicillin (narrow spectrum, not penicillinase resistant)
1-2
QUINOLONES
• Gram positives • anaerobic infections ( B. fragilis, C. perfringens )
useful in severe hospital or community-acquired
PENICILLINS
subunit, which prevents peptide bond formation Clinical Use
(including P. aeruginosa ) and good coverage of
integrity: osmotic lysis of the bacterium
G+ve
broad spectrum activity against Gram negatives
G+ve
peptidoglycan strands normally needed for cell wall
DNA GYRASE INHIBITORS (BACTERICIDAL)
(e.g.Clindamycin)
• inhibit protein synthesis by binding to 50S ribosomal
e.g. cefepime,cefpirome
proteins (PBPs) and prevents cross linking of
Pneumocystiscarinii , Toxoplasma , Shigella,
LINCOSAMIDES
coverage is required • beta-lactam ring competitively inhibits penicillin binding
• combination:
Salmonella , commonly used for urinary tract infections
generation)
BETA-LACTAMS
Clinical Use • SMX alone: Nocardia
an outpatient
crosses blood-brain barrier (unlike 1st and 2nd
Mode of Action
synthesis and bacterial growth
• Urinary Tract infections, Gram positive cocci
• Crohn’s disease, hepatic encephalopathy
Edited By Dr. Eyad Al-Kharashi (Jun 2007) Popup notes for Pediatric Practice added by Abdulnasir Al-Otaibi,MD.
Bacterial Classification Gram Stain
Aerobes Cocci
Gram +ve
Gram -ve
Anaerobes Rods
Staphylococcus - S.aureus - S.epidermidis - S.saprophyticus Streptococcus - S.pyogenes (Group A) - S.agalactiae (Group B) - Group D Strep (S. bovis) - S.viridans - S.pneumoniae Enterococcus
Streptococci/Peptostreptococci Corynebacteriumdiphtheriae Clostridium Listeria monocytogenes - C.tetani Bacillus cereus - C.botulinum Nocardia - C.perfringens - C.difficile
Neisseria - N.meningitidis - N.gonorrhea Moraxella catarrhalis
Escherichia coli Klebsiellapneumoniae Enterobacter spp. Proteus mirabilis Shigella Salmonella - S.typhi - S.enteritidis Pseudomonasaeruginosa Campylobacterjejuni Helicobacter pylori Vibrio cholerae Hemophilus - H.influenzae - H.ducreyi Bordetellapertussis Legionellapneumophila Yersinia - Y.enterocolitica - Y.pestis Pasteurellamultocida
Bacteroides - B.fragilis Fusobacterium
Un-detectable Mycobacterium, Spirochetes, Chlamydia, Bartonella, & Mycoplasma spp. (due to lack of cell wall)
Bacterial Classification Gram Stain
Aerobes Cocci
Gram +ve
Gram -ve
Anaerobes Rods
Staphylococcus - S.aureus - S.epidermidis - S.saprophyticus Streptococcus - S.pyogenes (Group A) - S.agalactiae (Group B) - Group D Strep (S. bovis) - S.viridans - S.pneumoniae Enterococcus
Streptococci/Peptostreptococci Corynebacteriumdiphtheriae Clostridium Listeria monocytogenes - C.tetani Bacillus cereus - C.botulinum Nocardia - C.perfringens - C.difficile
Neisseria - N.meningitidis - N.gonorrhea Moraxella catarrhalis
Escherichia coli Klebsiellapneumoniae Enterobacter spp. Proteus mirabilis Shigella Salmonella - S.typhi - S.enteritidis Pseudomonasaeruginosa Campylobacterjejuni Helicobacter pylori Vibrio cholerae Hemophilus - H.influenzae - H.ducreyi Bordetellapertussis Legionellapneumophila Yersinia - Y.enterocolitica - Y.pestis Pasteurellamultocida
Bacteroides - B.fragilis Fusobacterium
Un-detectable Mycobacterium, Spirochetes, Chlamydia, Bartonella, & Mycoplasma spp. (due to lack of cell wall)
Notes
i
1-1
CHLORAMPHENICOL : Rarely used today because of safety concerns and limited availability. May cause dose related or idiosyncratic bone marrow suppression and “Gray baby” syndrome. Occasionally plays a role in the management of pediatric infections, particularly those involving the CNS. Patients with meningitis who are allergic to "-lactam antibiotics and >1 month of age can be treated with chloramphenicol. Alternately, patients can be desensitized to the antibiotic.
1-2
FLUOROQUINOLONES: There is a reasonable body of evidence that the fluoroquinolones are safe, well tolerated, and effective against a variety of bacterial infections commonly encountered in pediatric practice. Parenteral quinolones are appropriate for critically ill patients with gram-negative infections. The use of oral quinolones in stable outpatients is also reasonable for treatment of infections that would otherwise require parenteral antibiotics (P. aeruginosa soft tissue infections such as osteochondritis) or selected genitourinary tract infections. Currently, fluoroquinolones are FDA approved for the following indications in children: nalidixic acid for UTIs, ciprofloxacin for inhalational anthrax and complicated UTI and pyelonephritis, and levofloxacin for inhalational anthrax. Use of fluoroquinolones in children should continue to be limited to treatment of infections for which no safe and effective alternative exists. Although fluoroquinolones are reasonably safe in children, cli nicians should be aware of the specific adverse reactions.
Notes
i
1-1
CHLORAMPHENICOL : Rarely used today because of safety concerns and limited availability. May cause dose related or idiosyncratic bone marrow suppression and “Gray baby” syndrome. Occasionally plays a role in the management of pediatric infections, particularly those involving the CNS. Patients with meningitis who are allergic to "-lactam antibiotics and >1 month of age can be treated with chloramphenicol. Alternately, patients can be desensitized to the antibiotic.
1-2
FLUOROQUINOLONES: There is a reasonable body of evidence that the fluoroquinolones are safe, well tolerated, and effective against a variety of bacterial infections commonly encountered in pediatric practice. Parenteral quinolones are appropriate for critically ill patients with gram-negative infections. The use of oral quinolones in stable outpatients is also reasonable for treatment of infections that would otherwise require parenteral antibiotics (P. aeruginosa soft tissue infections such as osteochondritis) or selected genitourinary tract infections. Currently, fluoroquinolones are FDA approved for the following indications in children: nalidixic acid for UTIs, ciprofloxacin for inhalational anthrax and complicated UTI and pyelonephritis, and levofloxacin for inhalational anthrax. Use of fluoroquinolones in children should continue to be limited to treatment of infections for which no safe and effective alternative exists. Although fluoroquinolones are reasonably safe in children, cli nicians should be aware of the specific adverse reactions.
1-3
TETRACYCLINES: Must be prescribed judiciously to children <8 yr of age, because they can cause staining of teeth, hypoplasia of dental enamel, and abnormal bone growth in this age group. Doxycycline is the most useful antimicrobial agent in treatment of brucellosis. Used in combination with Rifampin +/- Aminoglycoside. In children <8 yr Trimethoprim-sulfamethoxazole (TMP-SMZ) is an alternative.
References: : Nelson Textbook of Pediatrics, 18th ed. The Use of Systemic and Topical Fluoroquinolones, AAP.
Best luck Abdulnasir M. Al-Otaibi
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