Standardized susceptibility test procedures require the use of laboratory controls to monitor and ensure the accuracy and precision of the supplies and reagents used in the assay, and the techniques of the individuals performing the test1,2,3,4,5,6,7. Standard doxycycline and tetracycline powders should provide the following range of MIC values noted in Table 2. For the diffusion technique using the 30 mcg doxycycline disk the criteria noted in Table 2 should be achieved.
|QC Strain||Minimal Inhibitory Concentration mcg/mL||Zone Diameter (mm)||Agar Dilution (mcg/mL)|
|Enterococcus faecalis ATCC 29212|
|Doxycycline||2 — 8||–||–|
|Tetracycline||8 — 32||–||–|
|Escherichia coli ATCC 25922|
|Doxycycline||0.5 — 2||18 — 24||–|
|Tetracycline||0.5 — 2||18 — 25||–|
|Eubacteria lentum ATCC 43055|
|Haemophilus influenzae ATCC 49247|
|Tetracycline||4 — 32||14 — 22||–|
|Neisseria gonorrhoeae ATCC 49226|
|Tetracycline||–||30 — 42||0.25 — 1|
|Staphylococcus aureus ATCC 25923|
|Doxycycline||–||23 — 29||–|
|Tetracycline||–||24 — 30||–|
|Staphylococcus aureus ATCC 29213|
|Doxycycline||0.12 — 0.5||–||–|
|Tetracycline||0.12 — 1||–||–|
|Streptococcus pneumoniae ATCC 49619|
|Doxycycline||0.015 — 0.12||25 — 34||–|
|Tetracycline||0.06 — 0.5||27 — 31||–|
|Bacteroides fragilis ATCC 25285|
|Tetracycline||–||–||0.12 — 0.5|
|Bacteroides thetaiotaomicron ATCC 29741|
|Tetracycline||–||–||8 — 32|
|Mycoplasma pneumoniae ATCC 29342|
|Tetracycline||0.06 — 0.5||–||0.06 — 0.5|
|Ureaplasma urealyticum ATCC 33175|
Doxycycline Hyclate Indications and Usage
To reduce the development of drug-resistant bacteria and maintain effectiveness of Doxycycline Hyclate Tablets and other antibacterial drugs, Doxycycline Hyclate Tablets should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.
Doxycycline is indicated for the treatment of the following infections:
- Rocky Mountain spotted fever, typhus fever and the typhus group, Q fever, rickettsialpox, and tick fevers caused by Rickettsiae.
- Respiratory tract infections caused by Mycoplasma pneumoniae.
- Lymphogranuloma venereum caused by Chlamydia trachomatis.
- Psittacosis (ornithosis) caused by Chlamydophila psittaci.
- Trachoma caused by Chlamydia trachomatis, although the infectious agent is not always eliminated, as judged by immunofluorescence.
- Inclusion conjunctivitis caused by Chlamydia trachomatis.
- Uncomplicated urethral, endocervical, or rectal infections in adults caused by Chlamydia trachomatis.
- Nongonococcal urethritis caused by Ureaplasma urealyticum.
- Relapsing fever due to Borrelia recurrentis.
Doxycycline is also indicated for the treatment of infections caused by the following gram-negative microorganisms:
- Chancroid caused by Haemophilus ducreyi.
- Plague due to Yersinia pestis.
- Tularemia due to Francisella tularensis.
- Cholera caused by Vibrio cholerae.
- Campylobacter fetus infections caused by Campylobacter fetus (formerly Vibrio fetus).
- Brucellosis due to Brucella species (in conjunction with streptomycin).
- Bartonellosis due to Bartonella bacilliformis.
- Granuloma inguinale caused by Klebsiella granulomatis.
Because many strains of the following groups of microorganisms have been shown to be resistant to doxycycline, culture and susceptibility testing are recommended.
Doxycycline is indicated for treatment of infections caused by the following gram-negative bacteria, when bacteriologic testing indicates appropriate susceptibility to the drug:
- Escherichia coli.
- Enterobacter aerogenes.
- Shigella species.
- Acinetobacter species.
- Respiratory tract infections caused by Haemophilus influenzae.
- Respiratory tract and urinary tract infections caused by Klebsiella species.
Doxycycline is indicated for treatment of infections caused by the following gram-positive microorganisms when bacteriologic testing indicates appropriate susceptibility to the drug:
- Upper respiratory infections caused by Streptococcus pneumoniae.
- Anthrax due to Bacillus anthracis, including inhalational anthrax (post-exposure): to reduce the incidence or progression of disease following exposure to aerosolized Bacillus anthracis.
When penicillin is contraindicated, doxycycline is an alternative drug in the treatment of the following infections:
- Uncomplicated gonorrhea caused by Neisseria gonorrhoeae.
- Syphilis caused by Treponema pallidum.
- Yaws caused by Treponema pallidum subspecies pertenue.
- Listeriosis due to Listeria monocytogenes.
- Vincent’s infection caused by Fusobacterium fusiforme.
- Actinomycosis caused by Actinomyces israelii.
- Infections caused by Clostridium species.
In acute intestinal amebiasis, doxycycline may be a useful adjunct to amebicides.
In severe acne, doxycycline may be useful adjunctive therapy.
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