Doxycycline monohydrate microbiology
| Doxycycline monohydrate |
|---|
| DOXYCYCLINE MONOHYDRATE® FDA Package Insert |
| Description |
| Clinical Pharmacology |
| Microbiology |
| Indications and Usage |
| Contraindications |
| Warnings and Precautions |
| Adverse Reactions |
| Overdosage |
| Dosage and Administration |
| How Supplied |
| Labels and Packages |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mohamed Moubarak, M.D. [2]
Microbiology
The tetracyclines are primarily bacteriostatic and are thought to exert their antimicrobial effect by the inhibition of protein synthesis. The tetracyclines, including doxycycline, have a similar antimicrobial spectrum of activity against a wide range of gram-positive and gram-negative microorganisms. Cross-resistance of these microorganisms to tetracyclines is common.
Doxycycline has been shown to be active against most strains of the following microorganisms, both in vitro and in clinical infections as described in the INDICATIONS AND USAGE section.
Aerobic Gram-Positive Microorganisms:
Because many strains of the following groups of gram-positive microorganisms have been shown to be resistant to tetracyclines, culture and susceptibility testing are recommended.
Bacillus anthracis Listeria monocytogenes Staphylococcus aureus
- Doxycycline is not the drug of choice in the treatment of any type of staphylococcal infection.
Up to 44 percent of strains of Streptococcus pyogenes and 74 percent of Streptococcus faecalis have been found to be resistant to tetracycline drugs. Therefore, tetracyclines should not be used to treat streptococcal infections unless the microorganism has been demonstrated to be susceptible.
Aerobic Gram-Negative Microorganisms:
Bartonella bacilliformis Haemophilus ducreyi
Brucella species Haemophilus influenzae
Calymmatobacterium granulomatis Neisseria gonorrhoeae
Campylobacter fetus Vibrio cholerae
Francisella tularensis Yersinia pestis
Because many strains of the following groups of gram-negative microorganisms have been shown to be resistant to tetracyclines, culture and susceptibility testing are recommended:
Acinetobacter species Klebsiella species
Enterobacter aerogenes Shigella species
Anaerobic Microorganisms:
Actinomyces israelii Fusobacterium fusiforme
Other Microorganisms:
Borrelia recurrentis Rickettsiae
Chlamydia psittaci Treponema pallidum
Chlamydia trachomatis Treponema pertenue
Susceptibility Tests:
- Dilution Techniques:
Quantitative methods are used to determine antimicrobial minimum inhibitory concentrations (MIC’s). These MIC’s provide estimates of the susceptibility of bacteria to antimicrobial compounds. The MIC’s should be determined using a standardized procedure. Standardized procedures are based on a dilution method1,3 (broth or agar) or equivalent with standardized inoculum concentrations and standardized concentrations of tetracycline powder. The MIC values should be interpreted according to the following criteria: