Comparison of outbreak and nonoutbreak Acinetobacter baumannii strains by genotypic and phenotypic methods

Abstract

Thirty-one Acinetobacter baumannii strains, comprising 14 strains from 14 outbreaks in different northwestern European cities and 17 sporadic strains, were compared by investigating various properties of the strains including biotype, antibiogram, cell envelope protein electrophoretic profile, ribotype pattern, and the band pattern generated by a novel genomic fingerprinting method, named AFLP, which is based on the selective amplification of restriction fragments. Results showed that 12 strains from unrelated outbreaks were linked together in two clusters according to their similarities by these typing methods, whereas sporadic strains were more heterogeneous. Outbreak strains appeared to be markedly more resistant to antibiotics than nonoutbreak strains. The uniformity of typing characters in two sets of outbreak strains suggests that strains in each cluster have a common clonal origin.

Use of sequence-based typing and multiplex PCR to identify clonal lineages of outbreak strains of Acinetobacter baumannii

“…Diversity may be caused by movement of insertion sequences [32], a feature already recognised as being important in A. baumannii [27,[33][34][35]. The clonal lineages identified were found to correspond to pan-European clones I, II and III, defined by amplified fragment length polymorphism analysis (Group 1 corresponding to European clone II, Group 2 to European clone I, and Group 3 to European clone III), thus providing further evidence to support the original descriptions of these lineages [16,17]. Isolates can be assigned to these lineages with absolute certainty by sequence typing, while amplified fragment length polymorphism analysis may provide more ambiguous results.…”

“…Isolates can be assigned to these lineages with absolute certainty by sequence typing, while amplified fragment length polymorphism analysis may provide more ambiguous results. These sequence types were present in multiple and distant locations, and may arise in different hospitals through a combination of independent selection from very widespread common ancestors and some degree of spread, perhaps facilitated by patient transfers [16]. Perhaps 'outbreak' may not be the most appropriate term to apply to these strains, since their persistence may be a result, at least in part, of their continual selection in hospitals under antibiotic pressure, rather than a true outbreak situation.…”

Multiresistant Gram-negative bacteria: the role of high-risk clones in the dissemination of antibiotic resistance

“…The first description of the international lineages was based on comparisons of cell envelope protein profiling, ribotyping and AFLP genomic fingerprinting of epidemic and nonepidemic A. baumannii strains from geographically distinct European hospitals (Dijkshoorn et al, 1996). Since then, there have been abundant reports of outbreaks due to sublineages of these clones, including the French AYE VEB-1 strain (European clone I) (Naas et al, 2006), the United Kingdom OXA-23 clone 1 and the United Kingdom South East clone (European clone II) (Coelho et al, 2006).…”

The role of ISAba1 in expression of OXA carbapenemase genes in Acinetobacter baumannii

“…ISAba1 was sought as described by Segal et al (2005). PCR mapping experiments using combinations of First isolate date refers to recent years; UK isolates of this clone have been described before this date (Dijkshoorn et al, 1996).…”