From the Guidelines
Azithromycin is effective against a wide range of bacteria, including gram-positive, gram-negative, and atypical bacteria, such as Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella pneumophila. The antibiotic works by binding to the 50S subunit of bacterial ribosomes, inhibiting protein synthesis, which prevents bacterial growth and reproduction. It has a long half-life, allowing for once-daily dosing and often shorter treatment courses compared to other antibiotics.
Key Bacteria Targeted by Azithromycin
- Streptococcus pneumoniae
- Haemophilus influenzae
- Mycoplasma pneumoniae
- Chlamydia pneumoniae
- Legionella pneumophila
- Staphylococcus aureus
- Streptococcus pyogenes
- Chlamydia trachomatis
- Neisseria gonorrhoeae
Treatment Uses
- Respiratory tract infections
- Skin and soft tissue infections
- Sexually transmitted infections
- Certain gastrointestinal infections According to the most recent and highest quality study, azithromycin is recommended as the first-line agent for the treatment of dysentery and acute watery diarrhea with greater than mild fever 1. This is due to its efficacy against a wide range of bacteria, including those that are resistant to other antibiotics, such as fluoroquinolones. Additionally, azithromycin has been shown to be well-tolerated with minimal side effects, making it a suitable option for the treatment of travelers' diarrhea.
From the FDA Drug Label
Azithromycin has been shown to be active against most isolates of the following bacteria, both in vitro and in clinical infections (see INDICATIONS AND USAGE) Gram-positive bacteria Staphylococcus aureus Streptococcus agalactiae Streptococcus pneumoniae Streptococcus pyogenes Gram-negative bacteria Haemophilus ducreyi Haemophilus influenzae Moraxella catarrhalis Neisseria gonorrhoeae “Other” bacteria Chlamydophila pneumoniae Chlamydia trachomatis Mycoplasma pneumoniae
The bacteria that azithromycin is effective against include:
- Gram-positive bacteria:
- Staphylococcus aureus
- Streptococcus agalactiae
- Streptococcus pneumoniae
- Streptococcus pyogenes
- Gram-negative bacteria:
- Haemophilus ducreyi
- Haemophilus influenzae
- Moraxella catarrhalis
- Neisseria gonorrhoeae
- Other bacteria:
- Chlamydophila pneumoniae
- Chlamydia trachomatis
- Mycoplasma pneumoniae 2
From the Research
Types of Bacteria Affected by Azithromycin
- Azithromycin is effective against a variety of bacteria, including:
- Gram-positive organisms, although it is marginally less active than erythromycin in vitro 3
- Gram-negative pathogens, such as Haemophilus influenzae, H. parainfluenzae, Moraxella catarrhalis, Neisseria gonorrhoeae, Urea-plasma urealyticum, and Borrelia burgdorferi 3
- Streptococcus pneumoniae, although its efficacy may be reduced in cases of macrolide-resistant strains 4
- Haemophilus influenzae, although azithromycin may be less effective than amoxicillin-clavulanate in some cases 5, 6
Spectrum of Antimicrobial Activity
- Azithromycin has a similar spectrum of antimicrobial activity to erythromycin, but with some differences in its efficacy against certain bacteria 3
- Azithromycin is more active than erythromycin against many Gram-negative pathogens, but less active against some Gram-positive organisms 3
- The activity of azithromycin is unaffected by the production of beta-lactamase, but erythromycin-resistant organisms are also resistant to azithromycin 3
Clinical Efficacy
- Azithromycin has been shown to be effective in the treatment of various infections, including: