Anti Microbal Flashcards
kill either Gram-positive or Gram-negative bacteria
Narrow-spectrum antibiotics:
kill both Gram positives and Gram negatives.
Broad-spectrum antibiotics:
referred to as B-lactam drugs
PENICILLINS
molecular structure includes a four sided ring structure known as a
B-lactam ring
they are produced and can be purified directly from cultures of Penicillium moulds
• Penicillin G and Penicillin V.
NATURAL PENICILLINS
also B-lactam antibiotics and, like penicillin, are
produced by moulds.
• interfere with cell wall synthesis
• are bactericidal
CEPHALOSPORINS
agents are active primarily against Gram-positive bacteria.
First-generation
have increased activity against Gram- negative
bacteria
Second-generation cephalosporins
have even greater activity against Gram negatives
Third-generation cephalosporins
active against both Gram positives and Grams negatives, including P . Aeruginosa. e.g., Cefepime
Fourth-generation
expanded activity against aerobic Gram-positive cocci, including methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis MRSE e g., Ceftaroline
Fifth-generation
powerful antibacterial
• e.g,imipenem &. meropenem
• target the cell envelope
- have excellent activity against a broad spectrum of
bacteria, including many aerobic Gram-positive bacteria, most aerobic Gram-negative bacteria, and most anaerobes.
CARBAPENEMS
• target the cell envelope.
• e.g.,vancomyci
• have excellent activity against most aerobic and
anaerobic Gram-positive bacteria.
• enterococci, are becoming resistant to these drugs
• have a number of toxic side effects.
GLYCOPEPTIDES
major factor that limits their use is their toxicity
Aminoglycosides
• E.g., T obramycin, Gentamicin &. Amikacin
AMIKACIN
• inhibit protein synthesis
• bacteriostatic at lower doses and bactericidal at higher doses include erythromycin, clarithromycin, and azithromycin
• effective against: chlamydias, mycoplasmas, T . pallidum, and Legionella spp.
Azithromycin and Erythromycin
MACROLIDES
• bactericidal drugs inhibit DNA synthesis
The most commonly used, Ciprofloxacin and Levofloxacin effective against members of the tamiye Enterobacteriaceae and aeruginosa.
fluoroquinolone
• drugs inhibit production of folic acid (a vitamin) in those bacteria that require p-aminobenzoic acid (PABA) to synthesize folic acid*
Sulfamethoxazole + Trimethoprim
Sulfonamide
a single antimicrobial agent is not sufficient to destroy all the pathogens that develop during the course of a disease
• two or more drugs may be used simultaneously to kill all the pathogens to prevent resistant mutant pathogens from emerging
MULTIDRUG THERAPY
which multidrug-resistant strains of Mycobacterium tuberculosis are frequently encountered four drugs
isoniazid,
rifampin,
pyrazinamide, and
ethambutol
a parenteral antibiotic, was the first drug® used to treat TB.
Streptomycin
discovered in 1952, was the first oral drug preparation effective against the tubercle bacillus.
Isoniazid
is a bactericidal drug that inhibits tubercle cell wall synthesis and blocks pyridoxine (vitamin B6), which is used for intracellular enzyme production
soniazid
is taken alone, bacterial resistance occurs quickly
Rifampin
Most antifungal agents work in one of three ways:
• By binding with cell membrane sterols
nystatin and amphotericin B
Most antifungal agents work in one of three ways:
By interfering with sterol synthesis
clotrimazole and miconazole
Most antifungal agents work in one of three ways:
By blocking mitosis or nucleic acid synthesis
griseofulvin and 5-flucytosine
usually quite toxic to the host and work by:
• interfering with DNA and RNA synthesis
ANTIPROTOZOAL AGENTS
are agents used to attack Plasmodium at various stages of its life cycle
Antimalarials
acting against the red-blood-cell phase of the life cycle
schizonticidal
acting against the gametocytes
gametocytocidal
acting against the parasites that are developing in the mosquito
sporontocidal
was the first drug found to be effective in the treatment of malaria.
Quinine
directly toxic to parasites and decreases the ability of the parasite to synthesize DNA.
Chloroquine
first antiviral agent effective against human
immunodeficiency virus (HIV)
Zidovudine (also known as azidothymidine[AZT])
refer to an organism that is resistant to only one antimicrobial agent
Superbugs
a clinician must initiate therapy before
laboratory results are available
EMPIRIC THERAPY
drugs that can modify the immune response, either by enhancing or suppressing the immune system. They are used to fight infections, prevent and treat certain diseases.
Immunologic
