BASIC PRINCIPLES
Proper use-Favorable Results
Indiscriminate use- Drug Resistance Emerging Problem May produce Adverse Reactions
DECISION MAKING
Decide first that one is treating a Bacterial
Infection.
Mild -Wait
Moderate -Consider starting the earliest
Severe -Don’t lose time
( Best guess is life-saving)
SKILLS IN ANTIBIOTIC THERAPY
Seniors – Colleagues – Juniors Follow
Most General Practitioners
Dangerous trend Promotional
The best way to learn your own skills.
ETIOLOGICAL DIAGNOSIS
Do we need to know about causative agents
always? No
Development of skills applies to the situation.
But the following conditions warrant a good
knowledge of the causative agent.
CNS, Hepatobiliary, Renal Systemic infections,
Bacteremias Cardiac infections.
WHAT IS THE BEST GUESS
Past experience with Antibiotic therapy,
Basic principles of antibiotic therapy,
Many times best guess is life-saving.
Many surveys prove — Physicians in
Developing Nations
Depending on the Best guess.
ROLE OF MICROBIOLOGICAL DIAGNOSIS
Start collecting desired samples before
starting antibiotic therapy.
Consider the Technical soundness of the
Laboratories.
Many times Normal flora are reported as
pathogens and misguide the Junior
Physicians.
JUDGMENT ON CLINICAL RESPONSE
In routine circumstances, if the best guess
works ignore Microbiological reports
In Poor response consider the evaluation of
Microbiology reports.
ADHERENCE TO MICROBIOLOGY REPORTS
Isolates from Blood, CSF, Body Fluids,
A significant finding.
Implement the Microbiology Reports
DEALING WITH UNEXPECTED RESULTS
When the isolates from
Respiratory tract, GUT system Surface lesions.
Think before changing Antibiotics Many occasions Specimens are not properly collected.
Major failures are attributed to collecting and sending an ideal Sample.
DRUG SUSCEPTIBILITY TESTING
Always needed? No
e.g. Group A hemolytic streptococci.
Clostridial infection,
Most Important in Enterobacteriaceae Majority of the time stick to antibiotic
sensitivity patterns.
CURRENT TRENDS
Get familiar with your own ward reports.
All the knowledge from Journals May not suit local situations
Get familiar with Daily isolates and the Antibiotic patterns,
eg Pneumococcus,Enterococci
Be familiar with Changing patterns of resistance
e.g. Penicillin’s, Aminoglycosides, Vancomycin.
FAILED RESPONSES
One May not be treating a Bacterial
Infection.
Selection of Inappropriate Drug, Dosage,
Improper Administration.
Missing a Pocket of Localized pus,
Poorly diffusing drugs
Don’t reach target, e.g. Cefoperazone in
meningitis,
Superinfection replacing primary infection,
Suppression of Normal Flora.
Fast-emerging drug-resistant strains,
Two or More pathogens present
But treating one only.
Growing problems with
Immune deficiencies, Diabetes.
Treating noninfectious disorders with
Antibiotics eg Autoimmune disorders.
Slow Responses
Osteomyelitis, Endocarditis,
Slow-responding microbes,
Staphylococcus, Fungal
Mycobacterial infections.
Fast Responders Viridians Streptococci.
ESTIMATION OF ANTIBIOTIC LEVELS
Important on prolonged usage.
e.g. Aminoglycosides, Flucytosine,
In all cases of altered clearance. (Renal
Diseases.)
DURATION OF ANTIBIOTIC THERAPY
No specified guidelines for Major Infections.
Author variation is widely Controversial.
Most Important.
Effective clinical response.
Eg Clinical laboratory parameters in UTI
Location of infection
Endocarditis, Osteomyelitis.
ORAL OR PARENTAL ROUTE
Note
Oral Antibiotic therapy is equal to
parental therapy.
Oral Drugs now have excellent
Bioavailability.
ADVANTAGES OF ORAL THERAPY
Less expensive.
Early discharge from Hospital.
Reduction in Health care costs.
Avoid Chemical phlebitis.
Eliminate IV line infections.
It is proved that I.V offers no advantage over oral
therapy, except in critically ill.
A sense of security in patients.
MOST PROMINENT ORAL ANTIBIOTICS
Doxycycline,
Clindamycin.
Metronidazole.
Levofloxacin.
Chloramphenicol.
TMX-SMX.
Acyclovir.
Fluconazole.
Linezolid.
NEW USES OF OLD ANTIBIOTICS
Still useful on many occasions.
eg Doxycycline in Malaria.
Chloramphenicol – VRE.
ROLE OF NEWER ANTIBIOTICS
Do not come to prompt conclusions.
Consider-
1. Cost.
2 .Resistance potential.
3. Years of use.
4. Side effects.
5. Compare with current popular drugs.
6. Consider the profile of the last 2 year’s
usage.
NEW FACTS ON ANTIBIOTIC RESISTANCE
Drug resistance
Not related to
1. Volume of use.
2. Years of Use.
3. Class of Antibiotics
eg Cephalosporins.
But agent specific.
Ceftazidime.
NEW USES OF OLDER ANTIBIOTICS
1980 Beta-lactam / Quinolones Dominate the Antibiotic prescriptions.
LESS COMMONLY USED
Doxycycline,
Minocycline,
Clindamycin,
TMP-SMX
Nitrofurantoin.
TETRACYCLINE AND RELATED. DOXYCYCLINE, MINOCYCLINE
Can be used as the first line of Drugs in
Atypical pneumonia,
Chronic Bronchitis,
Leptospirosis,
Non-gonococcal urethritis,
C.trachomatis,
Syphilis, Leptospirosis ( Penicillin Allergy )
TRIMETHOPRIM-SULFAMETHOXAZOLE
Broad spectrum – Inexpensive.
Still useful in,
H.influenzae,
Moraxella,
E.coli.
Proteus mirabilis,
K.pneumoniae,
Shigella,
E.coli ( E.T )
Toxoplasmosis
MRSA ( some )
CLINDAMYCIN
Serious Anaerobic infections.
Polymicrobial osteomyelitis.
Infections associated with Diabetic foot.
Don’t Cross into CSF.
METRONIDAZOLE
Anaerobic bacterial infections,
Protozoal infections.
Anaerobic brain abscess.
H.pylori.
Clostridium difficile
CHLORAMPHENICOL
Pneumococcal infections
Meningococcal infections
H.influenzae
Anaerobic activity
VRE Enterococcus
RATIONALISM ON THE USE OF NEWER ANTIBIOTICS
Do not choose in Hurry,
Should possess unique attributes,
At least 2 years of experience before a
routine choice,
Many newer formulations have fewer side
effects and improved tolerability.
CONCLUSION
ANTIBIOTICS ARE LIFE-SAVING PEARLS, LET USE THEM PRECISELY, WISELY
TO A APPROPRIATE SITUATION.