Most respiratory tract infections are caused by viruses. Bacterial respiratory tract infections are usually treated empirically with antibiotic therapy that targets the most probable causative pathogens. Recommended antibiotic regimens for outpatient treatment of some common respiratory tract infections are listed in Table 1 for adults and Table 2 for children.

More antibiotics are prescribed for treatment of acute otitis media (AOM) than for any other infection in young children. Children with AOM typically present with otalgia, fever, and bulging and erythema of the tympanic membrane.

The FDA has licensed two new pneumococcal conjugate vaccines (PCVs) for prevention of invasive pneumococcal disease in adults: Prevnar 20 (PCV20; Pfizer), which contains antigens from 20 serotypes of pneumococcus, and Vaxneuvance (PCV15; Merck), which contains antigens from 15 serotypes. Two other pneumococcal vaccines are available in the US: Prevnar 13 (PCV13; Pfizer), a 13-valent conjugate vaccine licensed for use in persons ≥6 weeks old, and Pneumovax 23 (PPSV23; Merck), a 23-valent pneumococcal polysaccharide vaccine licensed for use in persons ≥2 years old.

Treatment of community-acquired pneumonia (CAP) is usually empiric, with selected antibiotic regimens directed against some of the most common causative pathogens. Recommended empiric regimens are listed in Table 2; recommended antibiotic dosages for treatment of CAP are listed in Tables 3 and 4. Joint guidelines for treatment of CAP by the American Thoracic Society and the Infectious Diseases Society of America (ATS/IDSA) were updated in 2019.

This issue includes reviews of drugs for glaucoma, age-related macular degeneration (AMD), bacterial conjunctivitis, and dry eye disease. Allergic conjunctivitis is reviewed in a separate issue.

Lefamulin (Xenleta – Nabriva), a semisynthetic pleuromutilin antibiotic, has been approved by the FDA for IV and oral treatment of community-acquired bacterial pneumonia (CABP) in adults. It is the first systemic pleuromutilin antibiotic to be approved in the US; retapamulin (Altabax), a 1% topical ointment for treatment of impetigo, was approved in 2007.

The FDA has approved omadacycline (Nuzyra – Paratek), a semisynthetic tetracycline derivative, for once-daily IV and oral treatment of community-acquired bacterial pneumonia (CAP) and acute bacterial skin and skin structure infections (ABSSSIs) in adults.

The FDA has warned that use of the macrolide antibiotic clarithromycin (Biaxin, and generics) may increase the risk of cardiovascular morbidity and mortality in patients with heart disease.

The FDA has approved delafloxacin (Baxdela – Melinta), an anionic fluoroquinolone antibiotic, for oral and parenteral treatment of adults with acute bacterial skin and skin structure infections (ABSSSIs), including those caused by methicillin-resistant Staphylococcus aureus (MRSA). It is the first fluoroquinolone to be approved for treatment of MRSA.

View the Comparison Table: Some Systemic Fluoroquinolones (online only)

Bacterial infections in adults are generally treated empirically, with the antibiotic covering most, but not all, of the potential causative pathogens. For some infections, culture and sensitivity testing can guide treatment, allowing for use of narrower-spectrum antibiotics. The recommended dosages and durations of antibiotic treatment for common respiratory, skin, and urinary tract infections are listed in Tables 1-3. Infectious disease experts now recommend shorter treatment durations for many infections to reduce the development of antimicrobial resistance and minimize adverse effects.

The FDA has approved Otovel (Arbor), a combination of the fluoroquinolone antibiotic ciprofloxacin 0.3% and the corticosteroid fluocinolone acetonide 0.025%, for otic treatment of acute otitis media with tympanostomy tubes (AOMT) in children ≥6 months old. It is the second fluoroquinolone/corticosteroid combination to be approved for this indication; ciprofloxacin 0.3%/dexamethasone 0.1% (Ciprodex) has been available for many years. In December 2015, a suspension of ciprofloxacin 6% (Otiprio) was approved for otic treatment of bilateral otitis media with effusion in children undergoing tympanostomy tube placement.

The FDA has announced that it is requiring changes in the labeling of systemic fluoroquinolones to warn that the risk of serious adverse effects, including tendinitis, peripheral neuropathy and CNS effects, generally outweighs their benefit for the treatment of acute sinusitis, acute exacerbations of chronic bronchitis, and uncomplicated urinary tract infections. For these infections, the new labels will recommend reserving fluoroquinolones for patients with no other treatment options.

The text that follows reviews some common bacterial infections and their empiric treatment pending the results of culture and susceptibility testing. The recommendations made here are based on the results of susceptibility studies, clinical trials, and the opinions of Medical Letter reviewers. Tables 1 and 2 list the usual dosages of antibacterial drugs.

Drugs for glaucoma, age-related macular degeneration, bacterial conjunctivitis, and dry eyes are reviewed here. Drugs for the treatment of allergic conjunctivitis will be reviewed in a future issue of Treatment Guidelines on Drugs for Allergic Disorders.

A Medical Letter reader has asked us to review the safety of the fluoroquinolone antibiotic levofloxacin (Levaquin – Ortho-McNeil-Janssen), which has just been approved for generic use by the FDA and has been at the center of some recent lawsuits regarding the adequacy of its safety warnings.

The FDA has approved ceftaroline fosamil (Teflaro – Forest), an intravenous (IV) cephalosporin, for treatment of acute bacterial skin and skin structure infections, including those caused by methicillin-resistant Staphylococcus aureus (MRSA), and for treatment of community-acquired bacterial pneumonia in adults. It is the first beta-lactam antibiotic approved for treatment of MRSA.

Telavancin (Vibativ - Astellas and Theravance), a lipoglycopeptide derivative of vancomycin (Vancocin, and others), has received FDA approval for treatment of complicated skin and skin structure infections caused by susceptible gram-positive bacteria in adults.

The FDA has approved the fluoroquinolone besifloxacin 0.6% ophthalmic suspension (Besivance - Bausch & Lomb) for treatment of bacterial conjunctivitis caused by susceptible bacteria. According to the manufacturer, this product was developed specifically for ophthalmic use in a specialized vehicle designed to prolong contact time on the ocular surface. Besifloxacin is not available for systemic use.

Although immunization programs have produced high vaccination rates in US infants and children, similar successes have not been achieved in adults. Vaccines recommended for routine use in adults are reviewed here. Vaccines for travel are reviewed separately.

Information about empirical treatment of bacterial infections, emerging trends in antimicrobial resistance, new drugs and new data about older drugs continue to become available. Usual pathogens and empiric treatment for some common types of infections are summarized in the text and a table listing the drugs of choice and alternatives for each pathogen begins on page 40. The recommendations made here are based on the results of susceptibility studies, clinical trials and the opinions of Medical Letter consultants.

Tigecycline (Tygacil - Wyeth), a derivative of minocycline, is a new intravenous (IV) antibiotic approved for treatment of complicated intra-abdominal and skin and skin-structure infections.

Telithromycin (Ketek - Aventis) has been approved by the FDA for oral treatment of mild to moderate community-acquired pneumonia, acute exacerbations of chronic bronchitis and acute bacterial sinusitis in patients age 18 and older. The drug is the first in a new class of antibiotics, the ketolides, derived from the macrolide erythromycin. Telithromycin has been marketed in Europe since 2001.

New drugs for bacterial infections and new information about older drugs continue to become available. Empirical treatment of some common bacterial infections is discussed in this article. A table listing the drugs of choice and alternatives for each pathogen begins on page 18. These recommendations are based on results of susceptibility studies, clinical trials and the opinions of Medical Letter consultants. Local resistance patterns should be taken into account. Trade names are listed on page 24.

The choice of drugs for treatment of pneumonia depends on the most likely pathogens causing the infection and local antimicrobial resistance patterns. Factors such as severity of illness, presence of co-morbid conditions and whether the infection is community or hospital-acquired also need to be considered.

New drugs for treatment of bacterial infections and new information about older drugs continue to become available. Empirical treatment of some infections is discussed and a table listing the drugs of choice and alternatives for each pathogen are contained in this article. These recommendations are based on results of susceptibility studies, clinical trials and opinions of Medical Letter consultants. Local resistance patterns should be taken into account.

The FDA has approved a conjugate heptavalent pneumococcal vaccine for prevention of invasive pneumococcal disease in infants and children.

Since The Medical Letter last reviewed the choice of drugs for treatment of bacterial infections, a few new drugs and some new information about older drugs have become available.