What antibiotics cover Haemophilus (H.) influenzae?

From the Guidelines

Antibiotics that effectively cover Haemophilus influenzae infections include amoxicillin-clavulanate, third-generation cephalosporins like ceftriaxone or cefotaxime, and fluoroquinolones such as levofloxacin or moxifloxacin. The choice of antibiotic should be guided by the severity of the infection, local resistance patterns, and patient factors like allergies and comorbidities 1.

Key Considerations

• Beta-lactamase production is common in H. influenzae, making plain amoxicillin or ampicillin less reliable unless susceptibility is confirmed 1.
• For empiric therapy, beta-lactamase-stable antibiotics like amoxicillin-clavulanate (875/125 mg twice daily for 7-10 days) or third-generation cephalosporins are preferred 1.
• Fluoroquinolones such as levofloxacin (750 mg daily for 5 days) or moxifloxacin (400 mg daily for 5 days) are also effective options 1.
• For less severe infections, oral options include second-generation cephalosporins like cefuroxime (500 mg twice daily) or trimethoprim-sulfamethoxazole (160/800 mg twice daily) 1.
• In severe infections like meningitis, high-dose ceftriaxone or cefotaxime is recommended 1.
• For patients with penicillin allergies, azithromycin (500 mg on day 1, then 250 mg daily for 4 days) or fluoroquinolones are appropriate alternatives 1.

Treatment Duration

• The treatment duration for H. influenzae infections typically ranges from 5 to 14 days, depending on the severity of the infection and the patient's response to treatment 1.
• For example, amoxicillin-clavulanate may be given for 7-10 days, while fluoroquinolones like levofloxacin or moxifloxacin may be given for 5-7 days 1.

Special Considerations

• Local resistance patterns should be taken into account when selecting an antibiotic, as resistance rates can vary significantly depending on the region and the specific strain of H. influenzae 1.
• Patient factors like allergies and comorbidities should also be considered when choosing an antibiotic, as some patients may require alternative treatments due to potential interactions or contraindications 1.

From the FDA Drug Label

Gram-Negative Bacteria Haemophilus influenzae Haemophilus parainfluenzae

1.1 Lower Respiratory Tract Infections – caused by beta-lactamase–producing isolates of Haemophilus influenzae and Moraxella catarrhalis.

1. 2 Acute Bacterial Otitis Media – caused by beta-lactamase–producing isolates of H. influenzae and M. catarrhalis. 1.3 Sinusitis – caused by beta-lactamase–producing isolates of H. influenzae and M. catarrhalis.

Safety and effectiveness for pneumonia due to Haemophilus influenzae and Streptococcus pneumoniae were not documented bacteriologically in the pediatric clinical trial due to difficulty in obtaining specimens. Use of azithromycin for these two microorganisms is supported, however, by evidence from adequate and well-controlled studies in adults

The antibiotics that cover H. influenzae are:

• Levofloxacin 2
• Amoxicillin-clavulanate 3
• Azithromycin 4

From the Research

Antibiotics that Cover H. influenzae

• Amoxicillin/clavulanate is a broad-spectrum antibacterial that has been shown to be effective against H. influenzae, including beta-lactamase-producing strains 5, 6, 7, 8.
• Amoxicillin is also effective against H. influenzae, but its use may be limited by the presence of beta-lactamase-producing strains 6.
• Cefotaxime, cefuroxime, and azithromycin have also been shown to be effective against H. influenzae, although their use may be limited by resistance patterns and other factors 7, 9.
• Macrolides such as erythromycin, clarithromycin, and azithromycin have poor in vitro activity against H. influenzae and may not be effective in treating infections caused by this organism 6, 7, 9.

Specific Antibiotic Regimens

• Amoxicillin/clavulanate 90/6.4 mg/kg/day in two divided doses (Augmentin ES-600) is recommended for pediatric use in persistent or recurrent acute otitis media where there are risk factors for the involvement of beta-lactamase-producing strains or S. pneumoniae with reduced penicillin susceptibility 5.
• Amoxicillin/clavulanate 2000/125 mg twice daily (available as Augmentin XR in the USA) is recommended for adult respiratory tract infection due to drug-resistant pathogens, such as S. pneumoniae with reduced susceptibility to penicillin, as well as beta-lactamase-producing H. influenzae and M. catarrhalis 5.
• Azithromycin may be effective against H. influenzae, but its use is limited by its poor in vitro activity and unreliable efficacy in vivo 9.