Abstract
Carbapenem-resistant Acinetobacter baumannii strains belonging to international clonal lineage II (ICL-II) have become predominant in intensive care units (ICUs) throughout Italy. Between 2005 and 2009, the carbapenem-hydrolyzing class D β-lactamase (CHDL) bla OXA-23 gene became more prevalent than bla OXA-58 among epidemic ICL-II strains showing extensive genetic similarity. These findings posed the question of whether CHDL gene replacement occurred in the homogeneous ICL-II population or a new OXA-23 clone(s) emerged and spread in ICUs. In this study, the changes in the ICL-II A. baumannii population and CHDL gene carriage were investigated in 30 genetically related isolates collected during the bla OXA-58-to- bla OXA-23 transition period. Pulsotyping, randomly amplified polymorphic DNA (RAPD) analysis, and multilocus sequence typing (MLST) results were combined with multilocus variable-number tandem-repeat (VNTR) analysis (MLVA-8), siderotyping, and plasmid profiling to improve genotype-based discrimination between isolates. Pulsotyping, RAPD analysis, and MLST clustered isolates into a single type. MLVA-8 identified 19 types that clustered into three complexes. All OXA-23-producing isolates formed a single complex, while OXA-58 producers were split into two complexes. Southern blot analysis of the physical localization and genetic context of the CHDL genes showed that bla OXA-58 was invariably located on plasmids, while bla OXA-23 was present within Tn2006 on the chromosome or both the chromosome and plasmids. These data indicate that the apparently homogeneous population of CHDL-producing ICL-II strains was composed of several independent strains and that, between 2005 and 2009, distinct OXA-23 producers displaced the preexisting OXA-58 producers. Thus, MLVA-8 appears to be a suitable tool not only for investigating A. baumannii population structure but also for high-resolution epidemiological typing.
| Original language | English |
|---|---|
| Pages (from-to) | 590-597 |
| Number of pages | 8 |
| Journal | Journal of Clinical Microbiology |
| Volume | 50 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - Mar 2012 |
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ASJC Scopus subject areas
- Microbiology (medical)
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Evidence of diversity among epidemiologically related carbapenemase- producing Acinetobacter baumannii strains belonging to international clonal lineage II. / Minandri, Fabrizia; D'Arezzo, Silvia; Antunes, Luísa C S; Pourcel, Christine; Principe, Luigi; Petrosillo, Nicola; Visca, Paolo.
In: Journal of Clinical Microbiology, Vol. 50, No. 3, 03.2012, p. 590-597.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Evidence of diversity among epidemiologically related carbapenemase- producing Acinetobacter baumannii strains belonging to international clonal lineage II
AU - Minandri, Fabrizia
AU - D'Arezzo, Silvia
AU - Antunes, Luísa C S
AU - Pourcel, Christine
AU - Principe, Luigi
AU - Petrosillo, Nicola
AU - Visca, Paolo
PY - 2012/3
Y1 - 2012/3
N2 - Carbapenem-resistant Acinetobacter baumannii strains belonging to international clonal lineage II (ICL-II) have become predominant in intensive care units (ICUs) throughout Italy. Between 2005 and 2009, the carbapenem-hydrolyzing class D β-lactamase (CHDL) bla OXA-23 gene became more prevalent than bla OXA-58 among epidemic ICL-II strains showing extensive genetic similarity. These findings posed the question of whether CHDL gene replacement occurred in the homogeneous ICL-II population or a new OXA-23 clone(s) emerged and spread in ICUs. In this study, the changes in the ICL-II A. baumannii population and CHDL gene carriage were investigated in 30 genetically related isolates collected during the bla OXA-58-to- bla OXA-23 transition period. Pulsotyping, randomly amplified polymorphic DNA (RAPD) analysis, and multilocus sequence typing (MLST) results were combined with multilocus variable-number tandem-repeat (VNTR) analysis (MLVA-8), siderotyping, and plasmid profiling to improve genotype-based discrimination between isolates. Pulsotyping, RAPD analysis, and MLST clustered isolates into a single type. MLVA-8 identified 19 types that clustered into three complexes. All OXA-23-producing isolates formed a single complex, while OXA-58 producers were split into two complexes. Southern blot analysis of the physical localization and genetic context of the CHDL genes showed that bla OXA-58 was invariably located on plasmids, while bla OXA-23 was present within Tn2006 on the chromosome or both the chromosome and plasmids. These data indicate that the apparently homogeneous population of CHDL-producing ICL-II strains was composed of several independent strains and that, between 2005 and 2009, distinct OXA-23 producers displaced the preexisting OXA-58 producers. Thus, MLVA-8 appears to be a suitable tool not only for investigating A. baumannii population structure but also for high-resolution epidemiological typing.
AB - Carbapenem-resistant Acinetobacter baumannii strains belonging to international clonal lineage II (ICL-II) have become predominant in intensive care units (ICUs) throughout Italy. Between 2005 and 2009, the carbapenem-hydrolyzing class D β-lactamase (CHDL) bla OXA-23 gene became more prevalent than bla OXA-58 among epidemic ICL-II strains showing extensive genetic similarity. These findings posed the question of whether CHDL gene replacement occurred in the homogeneous ICL-II population or a new OXA-23 clone(s) emerged and spread in ICUs. In this study, the changes in the ICL-II A. baumannii population and CHDL gene carriage were investigated in 30 genetically related isolates collected during the bla OXA-58-to- bla OXA-23 transition period. Pulsotyping, randomly amplified polymorphic DNA (RAPD) analysis, and multilocus sequence typing (MLST) results were combined with multilocus variable-number tandem-repeat (VNTR) analysis (MLVA-8), siderotyping, and plasmid profiling to improve genotype-based discrimination between isolates. Pulsotyping, RAPD analysis, and MLST clustered isolates into a single type. MLVA-8 identified 19 types that clustered into three complexes. All OXA-23-producing isolates formed a single complex, while OXA-58 producers were split into two complexes. Southern blot analysis of the physical localization and genetic context of the CHDL genes showed that bla OXA-58 was invariably located on plasmids, while bla OXA-23 was present within Tn2006 on the chromosome or both the chromosome and plasmids. These data indicate that the apparently homogeneous population of CHDL-producing ICL-II strains was composed of several independent strains and that, between 2005 and 2009, distinct OXA-23 producers displaced the preexisting OXA-58 producers. Thus, MLVA-8 appears to be a suitable tool not only for investigating A. baumannii population structure but also for high-resolution epidemiological typing.
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UR - http://www.scopus.com/inward/citedby.url?scp=84857407362&partnerID=8YFLogxK
U2 - 10.1128/JCM.05555-11
DO - 10.1128/JCM.05555-11
M3 - Article
C2 - 22205821
AN - SCOPUS:84857407362
VL - 50
SP - 590
EP - 597
JO - Journal of Clinical Microbiology
JF - Journal of Clinical Microbiology
SN - 0095-1137
IS - 3
ER -