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Ten-year trend in aminoglycoside resistance from a worldwide collection of Gram-negative pathogens (19982007)

Abstract number: P636

Biedenbach D., Jones R., Miller G., Armstrong E.

Objectives: To assess resistance (R) trends to aminoglycosides (AG) over ten years from a global sample of Gram-negative (GN) pathogens. This study determined the R rates of gentamicin (GEN), tobramycin (TOB) and amikacin (AMK) against nine common GN species groups from medical centres in North America (NA), Latin America (LA), Europe (EU) and Asia-Pacific (APAC).

Methods: Non-duplicate isolates from bloodstream and respiratory tract infections were collected from 38 countries between 1998–2000 (27,491 strains) and 2005–2007 (30,430 strains) via the SENTRY Program. Organisms included E. coli (EC), Klebsiella spp. (KBS), Enterobacter spp. (EBS), Citrobacter spp. (CBS), Serratia spp. (SER), P. mirabilis (PM), Indole + Proteae (IPP), P. aeruginosa (PSA) and Acinetobacter spp. (ACB). Susceptibility (S) testing was performed by two central monitoring laboratories using CLSI methods (M7-A7, M100-S18) and concurrent quality control testing.

Results: With the exception of KBS in EU, R to GEN increased in all regions for the three most prevalent Enterobacteriaceae (listed first in the Table). Nearly all pathogens in NA showed increased GEN R rates (0.6–11.1%) during the last surveillance period (2005–2007), while significant variations were noted in other regions. The dramatic increase in GEN-R for nearly all species in APAC countries was due to strains sampled from countries not included in the earliest sample (e.g. India and Indonesia). Between 60–70% of the ACB were R to GEN in regions outside of NA, with the USA rate approaching 43% in the most recent years. R to all three AG agents for each of these pathogens was generally <1% among enteric pathogens from NA. However, much higher GEN/TOB/AMK-R rates were observed in other geographic areas for the most common Enterobacteriaceae, highest in LA 1.4–17.1% during both time periods. R to all three AG ranged from 3.1% (NA) to 25.3% (LA) for the PSA isolates collected during 2005–2007.

Conclusions: Significant geographic variability in AG S was observed in the analysis of this large sample of GN pathogens with highest R rates in LA and APAC. Although the AG-R-mechanisms associated with these isolates were not assessed (companion abstract) it appears that a new generation of AG compounds would be a valuable therapeutic alternative to GEN, TOB and AMK for GN infections.

Table

Organism% GEN R
1998–2000 (27,491 isolates)/2005–2007 (30,430 isolates)
 NALAEUAPAC
EC3.2/9.310.4/15.46.4/7.815.5/43.1
KBS3.9/7.930.5/38.420.9/12.312.0/37.6
EBS5.8/8.721.2/29.99.7/10.112.8/30.4
CBS3.2/3.826.5/12.514.1/5.05.4/28.4
SER2.7/3.926.0/20.614.8/8.922.8/13.2
PM6.4/6.336.1/28.120.2/11.06.2/21.5
IPP11.5/12.420.5/43.915.9/12.021.5/24.3
PSA14.7/12.638.6/36.730.0/22.615.7/33.6
ACB31.6/42.765.6/67.969.2/63.035.3/60.0
aIsolates were non-S to GEN.

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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