Diversity of Acinetobacter baumannii in Four French Military Hospitals, as Assessed by Multiple Locus Variable Number of Tandem Repeats Analysis

Abstract

BackgroundInfections by A. calcoaceticus-A. baumannii (ACB) complex isolates represent a serious threat for wounded and burn patients. Three international multidrug-resistant (MDR) clones (EU clone I-III) are responsible for a large proportion of nosocomial infections with A. baumannii but other emerging strains with high epidemic potential also occur.Methodology/Principal FindingsWe automatized a Multiple locus variable number of tandem repeats (VNTR) analysis (MLVA) protocol and used it to investigate the genetic diversity of 136 ACB isolates from four military hospitals and one childrens hospital. Acinetobacter sp other than baumannii isolates represented 22.6% (31/137) with a majority being A. pittii. The genotyping protocol designed for A.baumannii was also efficient to cluster A. pittii isolates. Fifty-five percent of A. baumannii isolates belonged to the two international clones I and II, and we identified new clones which members were found in the different hospitals. Analysis of two CRISPR-cas systems helped define two clonal complexes and provided phylogenetic information to help trace back their emergence.Conclusions/SignificanceThe increasing occurrence of A. baumannii infections in the hospital calls for measures to rapidly characterize the isolates and identify emerging clones. The automatized MLVA protocol can be the instrument for such surveys. In addition, the investigation of CRISPR/cas systems may give important keys to understand the evolution of some highly successful clonal complexes.

Significant spread of extensively drug-resistant Acinetobacter baumannii genotypes of clonal complex 92 among intensive care unit patients in a university hospital in southern Iran

“…Nevertheless, the marked discriminatory power of Abaum_0017 has been acknowledged, but there is also limited agreement with other typing methods, and hence this locus has been considered unsuitable for inclusion in a first-line MLVA scheme. In our study, the Abaum_3406 locus was present in approximately half of the isolates that were assessed, which supports recent data indicating a high degree of variability and polymorphism in Abaum_3406 [37]. Likewise, the poor amplification of this locus implies that it is not consistently present in A. baumannii isolates, suggesting that the distribution of VNTR loci differs between isolates from different geographical regions.…”

Comparison of Multiple-Locus Variable-Number Tandem-Repeat Analysis with Pulsed-Field Gel Electrophoresis Typing of Acinetobacter baumannii in China

“…In addition, significant association between drug sensitivity and Abaum_0826 amplification failure was revealed ( 2 test, P Ͻ 0.001). Another recent report obtained similar results (11). So, Abaum_0826 PCR failure may be a useful marker to reflect the non-IC identification or sensitive phenotype; thus, it was considered for the HGDI calculation and clustering analysis.…”

“…In contrast, multiple-locus variable-number tandem-repeat (VNTR) analysis (MLVA), based on the copy numbers of tandem-repeat units (TRs) of VNTR loci, is a highly reproducible and portable typing method and can be easily shared. So far, 10 VNTRs that provided sufficient repeat polymorphism for fine typing of clinical isolates have been described in A. baumannii, and three different selections of loci have been evaluated, including a 2-locus assay (9), an MLVA-8 scheme (10), and a partially automated MLVA-10 Orsay scheme (11).…”

Bacterial Strain Diversity Within Wounds

“…[84][85][86][87] The diversity and plasticity of Acinetobacter has made whole-genome sequencing a vital epidemiological tool. 88,89 Acinetobacter is highly capable of recombination, which has an impact on virulence.…”

“…90 The genus has a number of named species that occur in wounds, including Acinetobacter baumannii, Acinetobacter calcoaceticus, and Acinetobacter pittii. Scattered reports have identified more than one species or genotype recovered for a single patient (Hauck et al 84 identifies four such patients), even in a single wound sample, much like Staphylococcus, and have repeatedly identified mutations to antibiotic resistance during the course of infection. 91 However, systematic published data about strain diversity within a single species within single wounds do not appear to be available, and, given the methodological difficulties, suggestive unpublished data require extensive analysis and peer review before it can be given credence.…”