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.
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Int. J. Antimicrob. Agents · Aug 2009
ReviewFosfomycin for the treatment of infections caused by multidrug-resistant non-fermenting Gram-negative bacilli: a systematic review of microbiological, animal and clinical studies.
The treatment of multidrug-resistant (MDR), extensively drug-resistant or pandrug-resistant non-fermenting Gram-negative bacterial infections constitutes a challenge in an era of few new antibiotic choices. This mandates the re-evaluation of already existing antibiotics such as fosfomycin. We systematically reviewed the literature to assess the clinical and microbiological effectiveness of fosfomycin in the treatment of these infections by searching PubMed, Scopus and the Cochrane Library databases. ⋯ In six clinical studies, 33 patients with MDR P. aeruginosa infections (mainly pulmonary exacerbations of cystic fibrosis) received fosfomycin (25/33 in combination with other antibiotics); 91% of the patients clinically improved. In conclusion, fosfomycin could have a role as a therapeutic option against MDR P. aeruginosa infections. Further research is needed to clarify the potential utility of this agent.
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Int. J. Antimicrob. Agents · Jul 2009
Risk factors and clinical features of infections caused by plasmid-mediated AmpC beta-lactamase-producing Enterobacteriaceae.
A case-control study was performed with the objective of analysing risk factors and clinical features of infections caused by plasmid-mediated AmpC beta-lactamase (plasmid AmpC)-producing Enterobacteriaceae. All patients infected with plasmid AmpC-producing Enterobacteriaceae in two tertiary care hospitals from December 2006 to August 2007 were included. Plasmid AmpC enzymes were characterised by isoelectric focusing, enzyme inhibition assay and enzyme-specific polymerase chain reaction. ⋯ An independent risk factor for infection with plasmid AmpC-producing Enterobacteriaceae was the use of an oxyimino-cephalosporin within 1 month of plasmid AmpC infection [adjusted odds ratio (aOR), 10.8, 95% confidence interval (CI), 1.6-75.4; P=0.016], with the use of a urinary catheter showing borderline significance (aOR, 6, 95% CI 0.93-38.4; P=0.06). An independent risk factor for treatment failure at 72 h was infection due to plasmid AmpC-producing Enterobacteriaceae (aOR, 9.78, 95% CI 1.34-71.17; P=0.02). These results suggest that infections caused by plasmid AmpC-producing isolates significantly increase treatment failure at 72 h and that prior use of an oxyimino-cephalosporin is a risk factor for infections caused by plasmid AmpC-producing Enterobacteriaceae.