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| __NOTOC__ | | __NOTOC__ |
| {{Azithromycin}} | | {{Azithromycin (ophthalmic)}} |
| {{CMG}} | | {{CMG}}; {{AE}} {{SS}} |
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| ==Microbiology== | | ==Microbiology== |
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| Azithromycin acts by binding to the 50S ribosomal subunit of susceptible microorganisms and, thus, interfering with microbial protein synthesis. Nucleic acid synthesis is not affected. | | Azithromycin acts by binding to the 50S ribosomal subunit of susceptible microorganisms and interfering with microbial protein synthesis. |
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| Azithromycin concentrates in phagocytes and fibroblasts as demonstrated by in vitro incubation techniques. Using such methodology, the ratio of intracellular to extra-cellular concentration was >30 after one hour incubation. In vivo studies suggest that concentration in phagocytes may contribute to drug distribution to inflamed tissues. | | Azithromycin has been shown to be active against most isolates of the following microorganisms, both in vitro and clinically in conjunctival infections [see Indications and Usage (1)]. |
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| Azithromycin has been shown to be active against most isolates of the following microorganisms, both in vitro and in clinical infections as described in the INDICATIONS AND USAGE section of the package insert for ZITHROMAX (azithromycin for injection).
| | * CDC coryneform group G2 |
| | * [[Haemophilus influenzae]] |
| | * [[Staphylococcus aureus]] |
| | * [[Streptococcus mitis]] group |
| | * [[Streptococcus pneumoniae]] |
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| ===Aerobic and facultative gram-positive microorganisms ===
| | The following in vitro data are also available, but their clinical significance in ophthalmic infections is unknown. The safety and effectiveness of AzaSite in treating ophthalmological infections due to these microorganisms have not been established. |
| *[[Staphylococcus aureus ]]
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| *[[Streptococcus pneumoniae]]
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| NOTE: Azithromycin demonstrates cross-resistance with erythromycin-resistant gram-positive strains. Most strains of Enterococcus faecalis and methicillin-resistant staphylococci are resistant to azithromycin.
| | The following microorganisms are considered susceptible when evaluated using systemic breakpoints. However, a correlation between the in vitro systemic breakpoint and ophthalmological efficacy has not been established. This list of microorganisms is provided as an aid only in assessing the potential treatment of conjunctival infections. |
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| ===Aerobic and facultative gram-negative microorganisms===
| | Azithromycin exhibits in vitro minimal inhibitory concentrations (MICs) of equal or less (systemic susceptible breakpoint) against most (≥90%) of isolates of the following ocular pathogens: |
| *[[Haemophilus influenzae ]]
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| *[[Moraxella catarrhalis ]]
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| *[[Neisseria gonorrhoeae]]
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| ==="Other" microorganisms ===
| | * [[Chlamydia pneumoniae]] |
| *[[Chlamydia pneumoniae ]] | | * [[Chlamydia trachomatis]] |
| *[[Chlamydia trachomatis ]] | | * [[Legionella pneumophila]] |
| *[[Legionella pneumophila ]] | | * [[Moraxella catarrhalis]] |
| *[[Mycoplasma hominis ]] | | * [[Mycoplasma hominis]] |
| *[[Mycoplasma pneumoniae]] | | * [[Mycoplasma pneumoniae]] |
| | * [[Neisseria gonorrhoeae]] |
| | * [[Peptostreptococcus]] species |
| | * [[Streptococci]] (Groups C, F, G) |
| | * [[Streptococcus pyogenes]] |
| | * [[Streptococcus agalactiae]] |
| | * [[Ureaplasma urealyticum]] |
| | * [[Viridans streptococci]] |
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| [[Beta-lactamase]] production should have no effect on azithromycin activity.
| | Efficacy for this organism was studied in fewer than 10 infections.<ref name="dailymed.nlm.nih.gov">{{Cite web | last = | first = |title = AZASITE (AZITHROMYCIN) SOLUTION [INSPIRE PHARMACEUTICALS, INC.] | url =http://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=5dc0f75a-1e14-469f-af4f-c668a32f2328 |publisher = | date = | accessdate = }}</ref> |
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| Azithromycin 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 of the package insert for ZITHROMAX (azithromycin tablets) and ZITHROMAX (azithromycin for oral suspension).
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| ===Aerobic and facultative gram-positive microorganisms ===
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| *[[Staphylococcus aureus ]]
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| *[[Streptococcus agalactiae ]]
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| *[[Streptococcus pneumoniae ]]
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| *[[Streptococcus pyogenes]]
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| ===Aerobic and facultative gram-negative microorganisms ===
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| *[[Haemophilus ducreyi ]]
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| *[[Haemophilus influenzae ]]
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| *[[Moraxella catarrhalis ]]
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| *[[Neisseria gonorrhoeae]]
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| ==="Other" microorganisms ===
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| *[[Chlamydia pneumoniae ]]
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| *[[Chlamydia trachomatis ]]
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| *[[Mycoplasma pneumoniae]]
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| [[Beta-lactamase]] production should have no effect on azithromycin activity.
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| The following in vitro data are available, but their clinical significance is unknown.
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| At least 90% of the following microorganisms exhibit an in vitro minimum inhibitory concentration (MIC) less than or equal to the susceptible breakpoints for azithromycin. However, the safety and effectiveness of azithromycin in treating clinical infections due to these microorganisms have not been established in adequate and well-controlled clinical trials.
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| ===Aerobic and facultative gram-positive microorganisms ===
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| *[[Streptococci]] (Groups C, F, G)
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| *Viridans group [[streptococci]]
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| ===Aerobic and facultative gram-negative microorganisms ===
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| *[[Bordetella pertussis]]
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| ===Anaerobic microorganisms ===
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| *[[Peptostreptococcus species]]
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| *[[Prevotella bivia]]
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| ==="Other" microorganisms ===
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| *[[Ureaplasma urealyticum]]
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| [[Beta-lactamase]] production should have no effect on azithromycin activity.
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| Susceptibility Testing Methods
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| When available, the results of in vitro susceptibility test results for antimicrobial drugs used in resident hospitals should be provided to the physician as periodic reports which describe the susceptibility profile of nosocomial and community-acquired pathogens. These reports may differ from susceptibility data obtained from outpatient use, but could aid the physician in selecting the most effective antimicrobial.
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| ===Dilution techniques===
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| Quantitative methods are used to determine antimicrobial minimum inhibitory concentrations (MICs). These MICs provide estimates of the susceptibility of bacteria to antimicrobial compounds. The MICs 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 azithromycin powder. The MIC values should be interpreted according to criteria provided in Table 3.
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| ===Diffusion technique===
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| Quantitative methods that require measurement of zone diameters also provide reproducible estimates of the susceptibility of bacteria to antimicrobial compounds. One such standardized procedure2,3 requires the use of standardized inoculum concentrations. This procedure uses paper disks impregnated with 15-µg azithromycin to test the susceptibility of microorganisms to azithromycin. The disk diffusion interpretive criteria are provided in Table 3.
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| No interpretive criteria have been established for testing [[Neisseria gonorrhoeae]]. This species is not usually tested.
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| A report of "susceptible" indicates that the pathogen is likely to be inhibited if the antimicrobial compound reaches the concentrations usually achievable. A report of "intermediate" indicates that the result should be considered equivocal, and, if the microorganism is not fully susceptible to alternative, clinically feasible drugs, the test should be repeated. This category implies possible clinical applicability in body sites where the drug is physiologically concentrated or in situations where high dosage of drug can be used. This category also provides a buffer zone which prevents small uncontrolled technical factors from causing major discrepancies in interpretation. A report of "resistant" indicates that the pathogen is not likely to be inhibited if the antimicrobial compound reaches the concentrations usually achievable; other therapy should be selected.<ref>{{Cite web | last = | first =|title = http://www.accessdata.fda.gov/drugsatfda_docs/label/2013/050710s039,050711s036,050784s023lbl.pdf | url =http://www.accessdata.fda.gov/drugsatfda_docs/label/2013/050710s039,050711s036,050784s023lbl.pdf | publisher = |date = | accessdate = }}</ref>
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| ==References== | | ==References== |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sheng Shi, M.D. [2]
Microbiology
Azithromycin acts by binding to the 50S ribosomal subunit of susceptible microorganisms and interfering with microbial protein synthesis.
Azithromycin has been shown to be active against most isolates of the following microorganisms, both in vitro and clinically in conjunctival infections [see Indications and Usage (1)].
The following in vitro data are also available, but their clinical significance in ophthalmic infections is unknown. The safety and effectiveness of AzaSite in treating ophthalmological infections due to these microorganisms have not been established.
The following microorganisms are considered susceptible when evaluated using systemic breakpoints. However, a correlation between the in vitro systemic breakpoint and ophthalmological efficacy has not been established. This list of microorganisms is provided as an aid only in assessing the potential treatment of conjunctival infections.
Azithromycin exhibits in vitro minimal inhibitory concentrations (MICs) of equal or less (systemic susceptible breakpoint) against most (≥90%) of isolates of the following ocular pathogens:
Efficacy for this organism was studied in fewer than 10 infections.[1]
References
Adapted from the FDA Package Insert.