DR. MABANAG - GENERAL PRINCIPLES OF ANTIMICROBIAL THERAPY Flashcards
one of the most commonly used and misused drugs.
Antimicrobials Agents
chemical agents or drugs that are selectively toxic to the causative agent of the disease such as virus, bacterium, or other organism.
Chemotherapeutic agents
antibacterial substances produced by various aspects of organisms like bacteria, fungi, and actinomycetes that suppress the growth of other microorganisms.
Antibiotic agents
DENGUE
Aedes aegypti
CHIKUNGUNYA
Aedes aegypti
Aedes albopictus.
aminoglycoside toxicity
OTOTOXIC
NEPHROTOXIC
more pronounced in the elderly than the middle-aged adult
aminoglycoside toxicity
bind avidly to developing teeth and bones
TETRACYCLINES
Filipinos are one of the fastest acetylators of anti-TB drugs.
ISONIAZID
MALE OR FEMALE
have higher ACE-2 receptors, so more COVID-19 virus attaches to male patients
MALES
neurotoxicity OF ______ and _______
correlates with increased CSF drug concentration
typically occurs in patients with decreased renal function who are given large doses.
Penicillin G
B-lactam antibiotics
are antibiotics effective in abscesses?
NO
Antimicrobial activity decreases significantly in pus which contains phagocytes, cellular debris, and proteins that can bind drugs or create conditions unfavorable to drug action.
Some antibiotics ________ in low pH.
a. will work
b. wil not work
b. will not work
treatment of Urinary Tract Infection
FOSFOMYCIN
The location of the infection may dictate the
choice of drug and route of administration.
Brain infections -
Skin infections -
Brain infections - intravenous
Skin infections - topical or oral
the concentration of the drug that inhibits the growth of the bacteria.
MIC (Minimum Inhibitory Concentration)
Inhibition of cell wall synthesis
● Beta-lactams
○ Penicillin
○ Cephalosporins
○ Carbapenems
● Bacitracin
● Cycloserine
● Vancomycin
Inhibition of ribosomal protein synthesis (30s or 50s ribosomal sites)
BACTERIOSTATIC
○ Chloramphenicol
○ Erythromycin
○ Clindamycin
○ Streptogramin
○ Linezolid
○ Lincosamides
○ Macrolides
○ Fusidic Acid
Inhibition of ribosomal protein synthesis (30s or 50s ribosomal sites)
Agents that bind to the 30s ribosomal subunit and alter protein synthesis
BACTERICIDAL
○ Aminoglycosides
○ Tetracyclines
buy AT 30
CEL at 50
inhibits RNA polymerase
Rifamycin
○ Rifampicin/ Rifampin
○ Rifabutin
inhibits topoisomerase
Quinolones
○ Fluoroquinolones
inhibits DNA synthesis
Metronidazole
● Agents that act directly on the cell membrane, increasing permeability
● Leads to leakage in intracellular compounds
P-I-P
○ Polypeptides
○ Imidazoles
○ Polyene antibiotics
○ Polymyxin
○ Poly antifungal agents (such as Nystatin, Amphotericin B, which binds to cell wall sterols)
○ Lipopeptide Daptomycin
DETERGENTS
Block enzymes of folate metabolites
○ Trimethoprim
○ Sulfonamides
● Beta lactams
● Aminoglycosides
● Vancomycin
● Polypeptides
● Metronidazole
● Quinolones
● Rifampicin
● Isoniazid
Cidal (Bactericidal)
Primary Static (Bacteriostatic)
CMELTTS
● Chloramphenicol
● Macrolides
● Ethambutol
● Lincosamides
● Tetracyclines
● Trimethoprim
● Sulfonamides
Giving of antimicrobial before actual identification or isolation of infecting microorganism.
EMPIRIC THERAPY
An ultimate goal in administering a drug. As much as possible, the side effects or adverse effects that are usually seen in antimicrobial treatment should be avoided.
SELECTIVE TOXICITY
affects 70S ribosomes
CHLORAMPENICOL
inhibit bacterial FA (folic acid) synthesis
SULFONAMIDES
Persistent suppression of bacterial growth after limited exposure to the antimicrobial agent (even if you stop giving the antibiotic).
POST ANTIBIOTIC EFFECT (PAE)
Giving of antimicrobial drugs to a healthy person exposed to an infectious agent to prevent that person from acquiring the infection.
CHEMOPROPHYLAXIS
prophylaxis against leptospirosis
DOXYCYCLINE
Use of antimicrobial compounds to prevent infections remains controversial in numerous situations.
CHEMOPROPHYLAXIS
used to protect healthy persons from acquisition of or invasion by specific microorganisms to which they are exposed.
PROPHYLAXIS
to prevent meningococcal meningitis in people who are in close contact with case
RIFAMPIN
Prevention of gonorrhea or syphilis after
contact with an infected person
Ceftriaxone penicillin
prevent recurrent UTI caused by E. coli
trimethoprim-sulfamethoxazole (co-trimoxazole)
prevent a variety of infections in patients undergoing organ transplant or receiving cancer chemotherapy.
ORAL FLUROQUINOLONE
Immunoprophylaxis
Immediate protection
long term protection
Immediate protection - PASSIVE (RABIES)
long term protection - ACTIVE (TETANUS TOXOID, COVID)
The simultaneous use of 2 or more antimicrobial agents is recommended in specifically defined situations based on pharmacological rationale, however selection of an appropriate combination
ANTIMICROBIAL COMBINATION
Enhance effect of drug
Vancomycin + aminoglycoside
SYNERGY
When antibiotics are combined, the antimicrobial coverage is broader.
● Trimethoprim + Sulfamethoxazole
(Co-trimoxazole)
● Amoxicillin + Clavulanic Acid
Extended Antimicrobial Spectrum
use decrease
toxicity
Aminoglycosides + Penicillin
Beta Lactams and Aminoglycosides
● E.g. Staphylococcus produces beta-lactamases which inhibit penicillin.
Enzymatic Inactivation or Modification
Altered Target Site: Decreased Affinity of the drug to the offending organism
Methicillin-Resistant Staphylococci
Altered Permeability of Bacterial Cell Wall
Beta Lactams and Fluoroquinolones
● Especially for beta-lactamases, cephalosporins
Alternate Pathway Bypassing Antimicrobial Action
Sulfonamides and Trimethoprim
TOOTH DISCOLORATION
tetracyclines
HEARING LOSS
aminoglycosides
NEPHROTOXICITY
aminoglycosides
These are indications for the clinical use of antimicrobial combinations, except:
a. Mixed infections
b. Severe infections of which the cause is
known
c. Enhancement of antibacterial activity in
specific infections
d. Prevention of the emergence of resistant
strains
b. Severe infections of which the cause is
known
T/F. Prophylaxis cannot be used to protect healthy
persons from acquisition of or invasion by specific
microorganisms to which they are exposed.
FALSE
This antimicrobial combination is recommended to
decrease toxicity.
a. Co-trimoxazole
b. Vancomycin + Ceftriaxone
c. Aminoglycosides + Penicillin
d. Amoxicillin + Penicillin
c. Aminoglycosides + Penicillin
What adverse events are caused by aminoglycosides?
a. Nephrotoxicity
b. Impaired hearing
c. Both
d. None
C. BOTH
T/F. For an antibiotic to be effective, it must reach its target in an inactive form.
FALSE
The following drugs inhibit protein synthesis at various sites, except:
a. Fusidic acid
b. Aminoglycosides
c. Chloramphenicol
d. Monobactams
D.MONOBACTAMS
The following are host susceptibility factors, except:
a. Age
b. Culture sensitivity
c. Genetics
d. General Health
B. CULTURE SENSITIVITY
This refers to the ability of the microbe to cause infection
a. Virulence factors
b. Selective toxicity
c. Infectivity
d. Minimum Bactericidal Concentration
C. INFECTIVITY
Administration of this drug can prevent meningococcal meningitis
A. Co-trimoxazole
B.Ceftriaxone
C. Rifampin
D. Fluoroquinolones
C. RIFAMPIN
T/F.
abscesses because their activity is increased in the presence of pus, which contains proteins that increase the binding capacity of drugs.
FALSE
