Whole-genome sequencing reveals two prolonged simultaneous outbreaks involving Pseudomonas aeruginosa high-risk strains ST111 and ST235 with resistance to quaternary ammonium compounds.

OBJECTIVE: Water-bearing systems are known as frequent Pseudomonas aeruginosa (PA) outbreak sources. However, many older buildings continue to have sanitary facilities in high-risk departments such as the ICU. We present two simultaneous prolonged multi-drug-resistant (MDR) PA outbreaks detected at the ICU of a pulmonology hospital, which were resolved by whole-genome sequencing (WGS). METHODS: Outbreak management and investigations were initiated in August 2019 after detecting two patients with nosocomial VIM-2-positive MDR PA. The investigations involved weekly patient screenings for four months and extensive environmental sampling for 15 months. All patient and environmental isolates were collected and analysed by WGS. RESULTS: From April to September 2019, we identified 10 patients with nosocomial MDR PA, including five VIM-2-positive strains. VIM-2-positive strains were also detected in nine sink drains, two toilets, and a cleaning bucket. WGS revealed that of 16 VIM-2-positive isolates, 14 were ST111 that carried qacE, or qacEΔ1 genes, whereas 13 isolates clustered (difference of ≤11 alleles by cgMLST). OXA-2 (two toilets), and OXA-2, OXA-74, PER-1 (two patients, three toilets) qacEΔ1-positive ST235 isolates dominated among VIM-2-negative isolates. The remaining seven PA strains were ST17, ST233, ST273, ST309 and ST446. Outbreak containment was achieved by replacing U-bends, and cleaning buckets, and switching from quaternary ammonium compounds (QUATs) to oxygen-releasing disinfectant products. CONCLUSION: Comprehension and management of two simultaneous MDR PA outbreaks involving the high-risk strains ST111 and ST235 were facilitated by precise control due to identification of different outbreak sources per strain, and by the in-silico detection of high-level QUATs resistance in all isolates.

Self-assembly of gold nanoparticles on deep eutectic solvent (DES) surfaces.

Self-assembly of gold nanoparticles was obtained by sputter deposition on DES. SAXS and TEM investigations reveal the formation of spherical nanoparticles with a mean diameter of 5 ± 0.5 nm. For extended sputtering times, the number density of AuNPs increases linearly and a very pronounced 1st and 2nd shell ordering is observed.

[Value of image analysis DNA cytometry in cancer of Vater's ampulla]. / Stellenwert der bildanalytischen DNS-Cytometrie beim Carcinom der Ampulla Vateri.

In 27 patients who underwent partial duodenopancreatectomy due to cancer of the ampulla of Vater, in addition to the TNM classification and usual morphologic criteria, the paraffin-embedded material underwent deparaffinization, was rehydrated, and was mechanically and enzymatically processed into a single-cell solution. For evaluating the DNA histogram this was analyzed with the help of automatic single cell cytophotometric study. At the time of DNA analysis the histomorphological data and the survival time of the patients were not known. In the univariate analysis the 5-year survival rate of patients with diploid or hypotriploid tumors (n = 12) was 69% of patients with diclonal (diploid-triploid n = 7, triploid-tetraploid n = 1) tumors was 62.5% and no patient with a triploid or hypertriploid tumor (n = 7) survived 5 years. No association could be found between the known prognostic criteria and the DNA content. The multivariate analysis shows that beside the lymph node status, the DNA content of tumor cells had a strong and independent influence on the prognosis in cancer of the ampulla of Vater.