SELECTED ARTICLES FROM THE RECENT LITERATURE 2005

10/6/05

Antibiotic resistance of invasive pneumococci

Summary
Background - An increasing resistance to antibiotics (ABx) of the strains of S. pneumoniae (Pneumo) involved in invasive infections has become a major therapeutic problem in some areas of the world.

Findings - Vanderkooi et al of the Univ of Toronto in Canada investigated resistance to ABx of Pneumo involved in invasive infections in 3,339 patients. They found that ABx use during the 3 months prior to the onset of the invasive infection was the most important risk factor in ABx resistance. The single most important risk factor for resistance to a particular ABx agent was use within the previous 3 months of an ABx agent in the same chemical class. Of the macrolide ABx, azithromycin appears to be preferentially selected for resistance.

Over the 8 year study period, the authors found that ABx resistance in their (Toronto) region increased from 1% to 6% for penicillin, 4.6% to 13% for erythromycin and from 0.3% to 1.2% for levofloxacin.

Reference
Clin Infect Dis 2005;40:1288-97

Editor's Comments
These findings are of considerable importance and sobering for those treating asthmatic patients. It has been found that Pneumo infections are a major trigger of worsening asthma. A recent study has found an increased frequency of invasive Pneumo infections in chronic asthmatics.

The incidence of Pneumo resistance to ABx does vary considerably in different regions of the world, as pointed out in an editorial accompanying this report (Clin Infect Dis 2005;40:1298-1300). The importance of the finding that individual macrolide ABx agents differ with regard to ABx resistance was also stressed in this editorial.

 

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