The FDA has approved Exblifep (Allecra), a fixed-dose combination of the cephalosporin cefepime and the beta-lactamase inhibitor enmetazobactam, for IV treatment of adults with complicated urinary tract infections (cUTIs), including pyelonephritis, caused by designated susceptible microorganisms (see Spectrum of Activity). Exblifep is the first product that contains enmetazobactam to be approved in the US.

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.

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.

Eravacycline (Xerava – Tetraphase), a new synthetic tetracycline antibiotic, has been approved by the FDA for IV treatment of complicated intra-abdominal infections (cIAIs) in adults. Eravacycline is structurally similar to tigecycline (Tygacil, and generics), a broad-spectrum tetracycline approved by the FDA for IV treatment of complicated skin and skin structure infections, complicated intra-abdominal infections, and community-acquired pneumonia. A higher rate of mortality has been reported with use of tigecycline compared to other antibacterial drugs; it should be used only when no suitable alternative is available.

The FDA has approved a 6% otic suspension formulation of the fluoroquinolone antibiotic ciprofloxacin (Otiprio – Otonomy) for single-dose treatment of acute otitis externa (swimmer's ear) caused by Pseudomonas aeruginosa or Staphylococcus aureus in patients ≥6 months old. Otiprio was approved earlier for prophylaxis in children with bilateral otitis media with effusion who are undergoing tympanostomy tube placement.

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)

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 FDA has approved ceftazidime/avibactam (Avycaz – Actavis) for IV treatment of complicated urinary tract and intra-abdominal infections in adults who have limited or no other treatment options. Ceftolozane/tazobactam (Zerbaxa – Cubist), another cephalosporin/beta-lactamase inhibitor combination, was approved in 2014.

The FDA has approved another solution of the aminoglycoside antibiotic tobramycin (Bethkis – Chiesi/Cornerstone) for oral inhalation via a nebulizer for management of cystic fibrosis (CF) patients with Pseudomonas aeruginosa.

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.

Inhaled antibiotics, which can achieve high concentrations in the lung with minimal systemic side effects, are probably the most effective therapy available for chronic Pseudomonas aeruginosa infection in patients with cystic fibrosis. An orally inhaled dry powder formulation of the aminoglycoside antibiotic tobramycin (Tobi Podhaler – Novartis) has been approved by the FDA for management of P. aeruginosa pulmonary infection in cystic fibrosis patients ≥6 years old. The new formulation is administered via a hand-held pocket-sized inhaler. Tobramycin is also available as an inhalation solution (Tobi) for administration via a nebulizer. An inhalation solution of aztreonam (Cayston), administered via a nebulizer, is also approved for this indication.

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.

The antibiotic aztreonam is now available as an inhalation solution (Cayston – Gilead) to improve respiratory symptoms in cystic fibrosis (CF) patients ≥7 years old colonized with Pseudomonas aeruginosa. It is the second inhaled antibiotic to be FDA-approved for this indication in CF patients; the aminoglycoside tobramycin (Tobi) was the first. Inhaled antibiotics offer the advantage of high airway concentrations while minimizing systemic side effects.

The text below reviews some common bacterial infections and their treatment. The recommendations made here are based on the results of susceptibility studies, clinical trials and the opinions of Medical Letter consultants.

Doripenem (Doribax - Ortho-McNeil Janssen), an intravenous (IV) carbapenem antibiotic with a spectrum of activity similar to that of imipenem and meropenem, has been approved by the FDA for treatment of complicated intra-abdominal and urinary tract infections. Use of doripenem for treatment of nosocomial pneumonia, including ventilator-associated pneumonia, is still under FDA review.

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.

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.

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.