Carbapenem (cfiA) resistance gene in Bacteroides fragilis group strains in Belgium
Abstract number: P912
Wybo I., Soetens O., Van Doorslaer K., Piérard D., Lauwers S.
Objectives: In a recent Belgian survey  3% of the B. fragilis group strains were not susceptible to meropenem. In our university hospital a decrease in susceptibility to meropenem was observed from 97% in 2005 to 92% and 93% in 2006 and the first 8 months of 2007 respectively. In isolates belonging to other species of the B. fragilis group isolates susceptibility to meropenem was 97% in 2006 and 100% in the other years. The purpose of this study was to determine the prevalence of the cfiA carbapenem resistance gene in B. fragilis group isolates collected for a Belgian survey for resistance in anaerobes and to look for the presence of the cfiA gene in meropenem non-susceptible strains of this group isolated in our hospital.
Methods: From October 2003 to February 2005 238 B. fragilis group strains (135 B. fragilis and 103 other species) were collected in 9 Belgian hospitals. Also included in this study were 15 meropenem non-susceptible strains isolated in our hospital. Meropenem susceptibility was determined by Etest®. The following breakpoints were used for susceptible and resistant strains: 4 and 16 mg/L. The strains were screened for cfiA gene by PCR with specific primers.
Results: Of 135 B. fragilis collected for the survey three showed reduced susceptibility (MIC=8) and three were resistant (1 with MIC=16 and 2 with MIC=32). All these isolates and three of four isolates with a MIC of 4 were cfiA gene positive. All B. fragilis isolates with a MIC less than 4, one Bacteroides fragilis isolate with a MIC of 4 and the 103 isolates from other species were cfiA gene negative.
Fifteen meropenem non-susceptible strains (MIC>4; 12 B. fragilis, 1 B. thetaiotaomicron, 1 B. ovatus and 1 B. vulgatis) were detected in our hospital since 2005. Eleven B. fragilis isolates were cfiA gene positive. The cfiA gene was not detected in the remaining B. fragilis strain (MIC=8) and in the other species.
Conclusion: The prevalence of the cfiA resistance gene in Belgian survey isolates (20032005) was 6.7% (9/135) in Bacteroides fragilis isolates. All except one of meropenem non-susceptible B. fragilis strains isolated in our hospital since 2005 were cfiA gene positive. The cfiA gene was not detected in other species of the B. fragilis group.
|Session name:||18th European Congress of Clinical Microbiology and Infectious Diseases|
|Back to top|