LONKS JR, GARAU J, GOMEZ L, XERCAVINS M, DE ECHAGUEN AO, MEDEIROS AA; Interscience Conference on Antimicrobial Agents and Chemotherapy (41st : 2001 : Chicago, Ill.).

Abstr Intersci Conf Antimicrob Agents Chemother Intersci Conf Antimicrob Agents Chemother. 2001 Dec 16-19; 41: abstract no. L-1850.

Miriam Hospital, Providence, RI

BACKGROUND: Some have questioned the clinical relevance of in vitro resistance to macrolides among S. pneumoniae. A matched case-control study was performed to determine whether clinical failures of macrolide therapy occurred more commonly among patients with invasive disease due to erythromycin-resistant pneumococci. METHODS: Data from 1987 to 2000 from 1 hospital in Spain and 3 hospitals in the United States were reviewed. Among 1,071 patients with pneumococcal bacteremia, 86 patients with an erythromycin non-susceptible isolate were included as cases. Controls (n=141) were patients with an erythromycin susceptible pneumococcal bacteremia matched for age, sex, location and year of bacteremia. RESULTS: Nineteen (22%) of the cases and none (0%) of the matched controls were taking a macrolide antibiotic when blood cultures were drawn (p=0.00000004). Ten of 11 isolates from Spain had the erm gene (ribosomal methylase) whereas 6 of 8 isolates from the United States had the mef gene (n=3) or the M phenotype (n=3), consistent with macrolide efflux. The MIC of erythromycin ranged from as low as 4 microg/ml in an isolate that contained the mef gene to >128 mg/ml in isolates with the erm gene. CONCLUSIONS: Invasive pneumococcal disease occurred on macrolide therapy only if the patient had an erythromycin non-susceptible isolate. These data support the clinical importance of in vitro macrolide resistance. Also, it suggest that current recommendations to use macrolides as first-line empiric treatment of community-acquired infections suspected to be of pneumococcal etiology need to be reconsidered. The use of a standardized computer database linking clinical, demographic, microbiological and antibiotic usage data from multiple hospitals would facilitate this type of analysis.

Publication Types:

• Meeting Abstracts

Keywords:

• Anti-Bacterial Agents
• Antigens, Bacterial
• Bacteremia
• Case-Control Studies
• Community-Acquired Infections
• Erythromycin
• Humans
• In Vitro
• Macrolides
• Microbial Sensitivity Tests
• Phenotype
• Spain
• Streptococcal Infections
• Streptococcus pneumoniae
• United States
• genetics
• immunology

Other ID:

• GWAIDS0030669

UI: 102270306

From Meeting Abstracts