title: Levofloxacin failure in a patient with pneumococcal pneumonia.
abstract: OBJECTIVE
  To report a case of levofloxacin failure in a patient with a penicillin-sensitive Streptococcus pneumoniae pneumonia.
  
  
  METHODS
  A previously healthy, immunocompetent, 53-year-old white man presented with penicillin-sensitive S. pneumoniae pneumonia. The patient was empirically placed on levofloxacin monotherapy, which was continued due to a local penicillin shortage. When the patient failed to improve, further susceptibility testing was ordered. The organism was found to have a penicillin minimum inhibitory concentration (MIC) of 0.023 microgram/mL and a levofloxacin MIC of 6 micrograms/mL. Effective antimicrobial therapy was delayed, as clinicians did not anticipate fluoroquinolone resistance.
  
  
  CONCLUSIONS
  Newer fluoroquinolones such as levofloxacin have good activity against most S. pneumoniae isolates and are used for the treatment of pneumonia. Although resistance to these agents is rare, it has been reported. Current guidelines from the National Committee for Clinical Laboratory Standards do not recommend initial fluoroquinolone susceptibility testing.
  
  
  CONCLUSIONS
  As fluoroquinolone resistance may not be identified by susceptibility patterns to other antibiotics, early fluoroquinolone susceptibility testing and increased awareness of resistance may aid clinicians in their treatment of pneumococcal disease.
authors.affiliation: University of Kentucky Chandler Medical Center, Lexington, KY, USA.
authors.forename: P E
authors.initials: PE
authors.lastname: Empey
authors.forename: H R
authors.initials: HR
authors.lastname: Jennings
authors.forename: A C
authors.initials: AC
authors.lastname: Thornton
authors.forename: R P
authors.initials: RP
authors.lastname: Rapp
authors.forename: M E
authors.initials: ME
authors.lastname: Evans
mesh_terms: D000890:Anti-Infective Agents / Q000627:therapeutic use*; D006801:Humans; D064704:Levofloxacin; D008297:Male; D008875:Middle Aged; D015242:Ofloxacin / Q000627:therapeutic use*; D010406:Penicillins / Q000494:pharmacology; D011018:Pneumonia, Pneumococcal / Q000188:drug therapy*; D013296:Streptococcus pneumoniae / Q000187:drug effects; D017211:Treatment Failure
chemical_list: D000890:Anti-Infective Agents; D010406:Penicillins; D064704:Levofloxacin; D015242:Ofloxacin