A 56-year-old woman comes to the emergency department due to a week of fever, dyspnea, and cough with productive, foul-smelling sputum. She has no chills or rigors. The patient was seen at an urgent care center for these symptoms 4 days ago and was prescribed a 5-day course of azithromycin to treat pneumonia. However, she continues to feel worse despite taking the medicine. She underwent an upper gastrointestinal endoscopy 10 days ago for a long history of heartburn. Temperature is 38.7 C (101.7 F), blood pressure is 130/80 mm Hg, pulse is 108/min, and respirations are 22/min. Dentition is poor. Crackles are heard over the right upper lung field. There are no cardiac murmurs. Abdomen is soft and nontender. Complete blood count shows leukocytes of 14,500/mm³. Chest x-ray reveals a right upper lobe infiltrate. Which of the following additional therapies would be most helpful for this patient's condition?

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This patient likely has an aspiration pneumonia due to anaerobes as a complication of upper gastrointestinal endoscopy. Patients with pneumonia caused by anaerobic organisms typically present with indolent symptoms such as fever, malaise, and a characteristic foul-smelling sputum. Poor dentition, which predisposes to a greater quantity of oral anaerobic organisms, increases the risk of anaerobic aspiration pneumonia. Other risk factors for aspiration include forms of upper airway instrumentation (eg, endotracheal or nasogastric tubes), gastroesophageal reflux, dysphagia, and impaired consciousness. The location of the infiltrate is gravity-dependent and differs according to the patient's position at the time of aspiration. In supine patients, the posterior segments of the upper lobes and superior segments of the lower lobes are most affected, whereas in erect patients the bases of the lower lobes and the right middle lobe are most affected. Adding an antibiotic, such as clindamycin, with anaerobic coverage is the most reasonable next step. Other regimens include metronidazole with amoxicillin, amoxicillin-clavulanate, or a carbapenem. High rates of failure are seen with metronidazole monotherapy. (Choice A) The combination of ampicillin and gentamicin has good synergism against gram-negative aerobes. However, many anaerobes produce beta-lactamases; consequently, using ampicillin without a beta-lactamase inhibitor (eg, sulbactam) is not ideal for anaerobic coverage. The triple combination of ampicillin, gentamicin, and metronidazole is sometimes used for abdominal infections. (Choice B) Ciprofloxacin has good gram-negative coverage but is not effective for anaerobic or most gram-positive organisms. (Choice D) Doxycycline is an appropriate antibiotic for outpatient community-acquired pneumonia in which macrolide resistance is suspected, but it does not have good activity against anaerobes. (Choice E) Trimethoprim-sulfamethoxazole is the drug of choice for Pneumocystis pneumonia and is effective against many gram-negative and gram-positive agents; however, it does not provide significant anaerobic coverage. Educational objective: In patients with fever and a cough productive of foul-smelling sputum after instrumentation of the upper airway or esophagus, an anaerobic lung infection should be suspected. Common antibiotic options for anaerobic coverage include metronidazole with amoxicillin, amoxicillin-clavulanate, and clindamycin. References: Healthcare-associated pneumonia and aspiration pneumonia. (http://www.ncbi.nlm.nih.gov/pubmed/25657850) Aspiration-induced lung injury. (http://www.ncbi.nlm.nih.gov/pubmed/21263315) Geriatric oral health and pneumonia risk. (http://www.ncbi.nlm.nih.gov/pubmed/15909270)

A 56-Year-Old Woman Comes to the Emergency Department Due to a Week