What types of bacterial infections do macrolides cover?

From the Guidelines

Macrolides are effective against a range of bacterial infections, primarily covering gram-positive organisms, atypical pathogens, and some gram-negative bacteria. They are particularly useful for treating respiratory infections caused by Streptococcus pneumoniae, Haemophilus influenzae, and atypical pathogens like Mycoplasma pneumoniae, Legionella pneumophila, and Chlamydophila pneumoniae 1. Macrolides also cover group A streptococci (Streptococcus pyogenes), which cause pharyngitis and skin infections. They are effective against Bordetella pertussis (whooping cough), Corynebacterium diphtheriae, and certain sexually transmitted infections like Chlamydia trachomatis. Common macrolides include erythromycin, azithromycin, and clarithromycin. These antibiotics work by binding to the 50S subunit of bacterial ribosomes, inhibiting protein synthesis 1. Macrolides are often chosen for patients with penicillin allergies and are valuable for their anti-inflammatory properties and good tissue penetration. However, increasing resistance, particularly among S. pneumoniae strains, has limited their use as first-line agents in some settings 1.

Some key points to consider when using macrolides include:

• Their effectiveness against atypical pathogens, making them a good choice for treating community-acquired pneumonia (CAP) 1
• Their limited activity against Haemophilus influenzae, with more than 98% of strains showing resistance due to efflux pumps 1
• The rising resistance of Mycoplasma pneumoniae to macrolides in some regions, such as Japan, highlighting the need for local surveillance studies 1
• The importance of proper use of antimicrobials to prevent the in vivo selection of resistance 1

Overall, macrolides remain a valuable option for treating various bacterial infections, but their use should be guided by local resistance patterns and patient-specific factors. The choice of macrolide should be based on the specific infection being treated, as well as the patient's medical history and potential allergies.

From the FDA Drug Label

1 INDICATIONS AND USAGE

1.1 Acute Bacterial Exacerbation of Chronic Bronchitis Clarithromycin extended-release tablets are indicated in adults for the treatment of mild to moderate infections caused by susceptible isolates due to Haemophilus influenzae, Haemophilus parainfluenzae, Moraxella catarrhalis,or Streptococcus pneumoniae

1. 2 Acute Maxillary Sinusitis Clarithromycin extended-release tablets (in adults) are indicated for the treatment of mild to moderate infections caused by susceptible isolates due to Haemophilus influenzae, Moraxella catarrhalis,or Streptococcus pneumoniae
2. 3 Community-Acquired Pneumonia Clarithromycin extended-release tablets are indicated for the treatment of mild to moderate infections caused by susceptible isolates due to: Haemophilus influenzae(in adults) Haemophilus parainfluenzae(in adults) Moraxella catarrhalis(in adults) Mycoplasma pneumoniae, Streptococcus pneumoniae, Chlamydophila pneumoniae(in adults)

Macrolides, such as clarithromycin, cover bacterial infections caused by susceptible isolates of:

• Haemophilus influenzae
• Haemophilus parainfluenzae
• Moraxella catarrhalis
• Streptococcus pneumoniae
• Mycoplasma pneumoniae
• Chlamydophila pneumoniae These infections include:
• Acute bacterial exacerbation of chronic bronchitis
• Acute maxillary sinusitis
• Community-acquired pneumonia 2

From the Research

Macrolide Coverage

Macrolides are a class of antibiotics that cover a wide range of bacterial infections, including:

• Respiratory tract infections, such as community-acquired pneumonia, caused by pathogens like Streptococcus pneumoniae, Haemophilus influenzae, and atypical bacteria like Chlamydia pneumoniae, Mycoplasma pneumoniae, and Legionella spp. 3, 4, 5, 6
• Skin and soft tissue infections, including those caused by Streptococcus pyogenes and Staphylococcus aureus 4, 6
• Infections caused by gram-positive aerobes, such as Streptococcus spp. and Staphylococcus aureus 4

Specific Pathogens Covered

Macrolides are effective against:

• Streptococcus pneumoniae, including some macrolide-resistant strains 4, 5, 6
• Haemophilus influenzae, with newer macrolides like azithromycin and clarithromycin showing greater activity than erythromycin 3, 4, 6
• Atypical respiratory pathogens, including Chlamydia pneumoniae, Mycoplasma pneumoniae, and Legionella spp. 3, 4, 5, 6
• Mycobacterium avium complex (MAC) and other nontuberculous mycobacteria, with clarithromycin being a key agent in the treatment of MAC infections 6

Limitations of Macrolide Coverage

Macrolides have limited activity against:

• Gram-negative bacteria, including Enterobacteriaceae and other ESKAPE pathogens, although newer synthetic macrolides are being developed to address this limitation 7
• Bacteria that have developed macrolide resistance, which is an increasing concern and may limit the clinical usefulness of macrolides in the future 4, 6