International journal of antimicrobial agents
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Int. J. Antimicrob. Agents · Oct 2009
Annual macrolide prescription rates and the emergence of macrolide resistance among Streptococcus pneumoniae in Canada from 1995 to 2005.
Over the last 20 years, Canadian pneumococcal surveillance studies have documented a steady rise in macrolide resistance. In the current study, we probed the nature of associations between the emergence of macrolide-resistant Streptococcus pneumoniae in Canada and changes in macrolide (azithromycin, clarithromycin and erythromycin) prescription rates. Macrolide susceptibility testing data for respiratory tract isolates of S. pneumoniae (n=15109) were acquired from two published national Canadian surveillance databases, and dispensed outpatient macrolide prescription data were acquired from the proprietary Intercontinental Medical Statistics (IMS) Health Canada CompuScript database. ⋯ When the data were analysed by provincial origin, no statistically significant associations were found between prescription rates of any macrolide and macrolide resistance rates by univariate and multivariate regression analyses. We conclude that increasing macrolide resistance among respiratory isolates of pneumococci in Canada from 1995 to 2005 was associated both with decreasing prescriptions for erythromycin and concurrent increases in prescriptions for azithromycin and clarithromycin (azithromycin>clarithromycin by univariate regression analysis). Resistance development is complex and factors other than macrolide use may also be associated with observed increases in macrolide resistance in Canada from 1995 to 2005.
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Int. J. Antimicrob. Agents · Oct 2009
Prevalence of plasmid-mediated AmpC beta-lactamases among Enterobacteriaceae in Algiers hospitals.
The aim of this study was to investigate the prevalence and diversity of plasmid-mediated AmpC cephalosporinases (PAcBLs) in clinical isolates of Enterobacteriaceae collected between 2003 and 2007 from three Algiers hospitals. Antibiograms were determined on Mueller-Hinton agar plates using the disk diffusion method, and minimum inhibitory concentrations were determined by Etest. Isolates resistant to cefoxitin or ceftazidime were screened for bla(CMY), bla(DHA), bla(FOX) and bla(ACC) as well as extended-spectrum beta-lactamase (ESBL) genes by polymerase chain reaction (PCR). ⋯ The prevalence of PAcBLs was 2.18% (11/505), comprising 8 CMY-2 and 3 DHA-1 enzymes. CTX-M-15 was co-produced with CMY-2 in three isolates and with DHA-1 in one isolate; the two remaining DHA-1-producers co-expressed SHV-12 ESBL. This is the first report of plasmid-mediated AmpC from Algeria, with the first detection of DHA-1 in Enterobacter cloacae.