Improved structural characterization of chromosomal breakpoints using high resolution custom array-CGH.

Array-CGH is a powerful tool for the rapid detection of genomic imbalances. By customizing the array it is possible to increase the resolution in a targeted genomic region of interest and determine the structure of the breakpoints with high accuracy, as well as to detect very small imbalances. We have used targeted custom arrays to zoom in on 38 chromosomal breakpoints from 12 different patients carrying both balanced and unbalanced rearrangements. We show that it is possible to characterize unbalanced breakpoints within 17-20,000 bp, depending on the structure of the genome. All of the deletion and duplication breakpoints were further refined and potential underlying molecular mechanisms of formation are discussed. In one of seven carriers of apparently balanced reciprocal translocations we detected a small deletion of 200 bp within the previously FISH-defined breakpoint, and in another patient, a large deletion of 11 Mb was identified on a chromosome not involved in the translocation. Targeted custom oligonucleotide arrays make it possible to perform fine mapping of breakpoints with a resolution within the breakpoint region much higher compared to commercially available array platforms. In addition, identification of small deletions or duplications in apparently balanced rearrangements may contribute to the identification of new disease causing genes.

New screening method to detect carriage of carbapenemase-producing Enterobacteriaceae in patients within 24 hours.

Rapid identification of patients colonized with carbapenemase-producing Enterobacteriaceae (CPE) is essential to prevent introduction and the spread of CPE in the hospital. This article presents the results of a new screening method to detect patients colonized with CPE within 24h after hospital admission. From high-risk patients rectal and throat swabs were collected and incubated overnight, after which DNA was isolated and tested for the most prevalent CPE genes (KPC, NDM, OXA-48, VIM and IMP) by a ligation-mediated real-time polymerase chain reaction. In 14 months 454 patients were screened; in six patients CPE were detected (carriage rate 1.3%).