Levofloxacin failure in a patient with pneumococcal pneumonia

OBJECTIVE: TO report a case of levofloxacin failure in a patient with a pen icillin-sensitive Streptococcus pneumoniae pneumonia. CASE SUMMARY: A previously healthy, immunocompetent, 53-year-old white man presented with penicillin-sensitive S. pneumoniae pneumonia. The patient wa s empirically placed on levofloxacin monotherapy, which was continued due t o a local penicillin shortage. When the patient failed to improve, further susceptibility testing was ordered. The organism was found to have a penici llin minimum inhibitory concentration (MIC) of 0.023 mug/mL and a levofloxa cin MIC of 6 mug/mL. Effective antimicrobial therapy was delayed, as clinic ians did not anticipate fluoroquinolone resistance. DISCUSSION: Newer fluoroquinolones such as levofloxacin have good activity against most S. pneumoniae isolates and are used for the treatment of pneum onia. Although resistance to these agents is rare, it has been reported. Cu rrent guidelines from the National Committee for Clinical Laboratory Standa rds do not recommend initial fluoroquinolone susceptibility testing. CONCLUSIONS: AS fluoroquinolone resistance may not be identified by suscept ibility patterns to other antibiotics, early fluoroquinolone susceptibility testing and increased awareness of resistance may aid clinicians in their treatment of pneumococcal disease.