Plasmid-Mediated Transmission of KPC-2 Carbapenemase in Enterobacteriaceae in Critically III Patients

Carbapenem-resistant Enterobacteriaceae (CRE) cause health care-associated infections worldwide, and they are of severe concern due to limited treatment options. We report an outbreak of KPC-2-producing CRE that was caused by horizontal transmission of a promiscuous plasmid across different genera of bacteria and hospitals in Germany. Eleven isolates (8 Citrobacter freundii, 2 Klebsiella oxytoca, and 1 Escherichia coli) were obtained from seven critically ill patients during the six months of the outbreak in 2016. One patient developed a CRE infection while the other six patients were CRE-colonized. Three patients died in the course of the hospital stay. Six of the seven patients carried the same C. freundii clone; one K. oxytoca clone was found in two patients, and one patient carried E. coli and C. freundii. Molecular analysis confirmed the presence of a conjugative, blaKPC-2-carrying 70 kb-IncN plasmid in C. freundii and E. coli and an 80 kb-IncN plasmid in K. oxytoca. All transconjugants harbored either the 70 or 80 kb plasmid with blaKPC-2, embedded within transposon variant Tn4401g. Whole genome sequencing and downstream bioinformatics analyses of all plasmid sequences showed an almost perfect match when compared to a blaKPC-2-carrying plasmid of a large outbreak in another German hospital two years earlier. Differences in plasmid sizes and open reading frames point to the presence of inserted mobile genetic elements. There are few outbreak reports worldwide on the transmission of blaKPC-2-carrying plasmids across different bacterial genera. Our data suggest a regional and supraregional spread of blaKPC-2-carrying IncN-plasmids harboring the Tn4401g isoform in Germany.</p

Plasmid-Mediated Transmission of KPC-2 Carbapenemase in Enterobacteriaceae in Critically Ill Patients

Carbapenem-resistant Enterobacteriaceae (CRE) cause health care-associated infections worldwide, and they are of severe concern due to limited treatment options. We report an outbreak of KPC-2-producing CRE that was caused by horizontal transmission of a promiscuous plasmid across different genera of bacteria and hospitals in Germany. Eleven isolates (8 Citrobacter freundii, 2 Klebsiella oxytoca, and 1 Escherichia coli) were obtained from seven critically ill patients during the six months of the outbreak in 2016. One patient developed a CRE infection while the other six patients were CRE-colonized. Three patients died in the course of the hospital stay. Six of the seven patients carried the same C. freundii clone; one K. oxytoca clone was found in two patients, and one patient carried E. coli and C. freundii. Molecular analysis confirmed the presence of a conjugative, blaKPC-2-carrying 70 kb-IncN plasmid in C. freundii and E. coli and an 80 kb-IncN plasmid in K. oxytoca. All transconjugants harbored either the 70 or 80 kb plasmid with blaKPC-2, embedded within transposon variant Tn4401g. Whole genome sequencing and downstream bioinformatics analyses of all plasmid sequences showed an almost perfect match when compared to a blaKPC-2-carrying plasmid of a large outbreak in another German hospital two years earlier. Differences in plasmid sizes and open reading frames point to the presence of inserted mobile genetic elements. There are few outbreak reports worldwide on the transmission of blaKPC-2-carrying plasmids across different bacterial genera. Our data suggest a regional and supraregional spread of blaKPC-2-carrying IncN-plasmids harboring the Tn4401g isoform in Germany

Investigations of methylated myxochelins and novel secondary metabolite families from myxobacteria

Der erste Teil dieser Arbeit befasst sich mit den kürzlich in einem LC-MS-Screening identifizierten methylierten Biscatecholat-Siderophoren Methylmyxochelin A und B aus Myxococcus xanthus DK1622. Ein biochemisches und aktivitätsbasiertes Screening des Proteinextrakts kombiniert mit einer MALDI-TOF-MS-Analyse und heterologer Expression von Zielproteinen führte zur Entdeckung und Charakterisierung der ersten beschriebenen Siderophor-Catechol-O-Methyltransferase, welche eine Spezifität gegenüber Myxochelin A zeigte. Ausgehend von Produktionsanalysen und in Kooperation durchgeführten koordinationschemischen Analysen wurde eine Hypothese zur Funktion von Methylmyxochelinen in der Eisenhomöostase formuliert. Der zweite Teil beschreibt die LC-MS-basierte Identifizierung und Isolierung der neuen myxobakteriellen Sekundärmetabolitfamilien Thaxteramide aus Jahnella thaxteri SBSr007 sowie Chondrodepside und Chondrosaride aus Chondromyces sp. SBCm009. Über in silico-Analysen konnten zwei PKS/NRPS-Biosynthesegencluster der Thaxteramide gefunden und spezifiziert werden. Für die Chondrodepside und Chondrosaride wurden hypothetische Biosynthesemodelle aufgestellt.The first part of this work addresses the methylated biscatecholate siderophores Methylmyxochelin A and B from Myxococcus xanthus DK1622 recently identified in a LC-MS-screening. A biochemical and activity-based screening of the protein extract combined with MALDI-TOF-MS analysis and heterologous expression of target proteins led to the discovery and characterization of the first described siderophore catechol-O-methyltransferase exhibiting high specificity towards Myxochelin A. Based on production analyses and analyses of the coordination chemistry performed in cooperation an inferential hypothesis for the function of Methylmyxochelins in iron homeostasis was postulated. The second part describes the LC-MS-based identification and isolation of the novel myxobacterial secondary metabolite families Thaxteramides from Jahnella thaxteri SBSr007 as well as Chondrodepsides and Chrondrosarides from Chondromyces sp. SBCm009. Via in silico-analyses two PKS/NRPS biosynthetic gene clusters for Thaxteramides were detected and specified. For Chondrodepsides and Chrondrosarides hypothetical biosynthetic models were proposed

Ablehnung der Behandlung von Patienten mit MRE in geriatrischen Kliniken und Rehabilitationseinrichtungen: Einzelfälle oder gängige Praxis?

Die Zunahme multiresistenter Erreger (MRE) stellt für alle Beteiligten im Gesundheitswesen eine große Herausforderung dar. Im Umgang mit MRE gilt es, die Balance zu wahren zwischen der Umsetzung sinnvoller Hygienemaßnahmen und der Erfüllung des Behandlungsauftrages, im Sinne einer gleichberechtigten und optimalen Patientenversorgung. Es existieren umfangreiche Empfehlungen der Kommission für Krankenhaushygiene und Infektionsprävention (KRINKO) zu Hygienemaßnahmen bei Infektionen oder Besiedlung mit multiresistenten gramnegativen Erregern (MRGN)1 und zur Prävention und Kontrolle von Methicillin-resistenten Staphylococcus-aureus-Stämmen (MRSA) in medizinischen und pflegerischen Einrichtungen2 sowie zum Umgang mit besiedelten/infizierten Patienten in Heimen.3 Da die Epidemiologie und die Verbreitungsdynamik von MRE in Abhängigkeit vom Patienten- und Einrichtungsprofil zwischen verschiedenen Einrichtungen erheblich variieren können, ist für die Festlegung von spezifisch angepassten Präventionsbündeln eine individuelle Risikoabwägung erforderlich. 1-4 Hierbei sollen insbesondere das Übertragungs-, Kolonisations- und Infektionsrisiko für den jeweiligen Patienten, die durchzuführende medizinische Maßnahme und das Risikoprofil der Einrichtung berücksichtigt werden. Ziel ist es, Patienten mit MRE sicher zu versorgen und andere Patienten sowie das Personal zu schützen. In diesem Bericht soll auf die Probleme, die bei der Verlegung von Patienten mit MRE-Besiedlung/-Infektion auftreten können, hingewiesen werden

“She Loves Nothing but Her Art”: Vibrant Marble and the Agency of the Female Artist in Louisa May Alcott’s “A Marble Woman, or The Mysterious Model”

At first glance, “A Marble Woman” (1865) seems to offer but a trite marriage plot, assuaging Louisa May Alcott’s contemporary readers while containing the heroine’s scandalous abilities. On a second and read through a new materialist critical lens, it becomes apparent how cunningly the female sculptor Cecil negotiates her creativity with the societal demands on the true woman and the marriage doctrine of her time. The sensational story’s twist reveals the female protagonist’s masterful manipulation of her guardian-husband Yorke who was, just as the reader, under the assumption that he was the one molding her to his needs. The protagonist’s true artistry, we realize, is not static sculpture but vibrant performance which renders her simultaneously as woman and marble, artist and an artwork

Mutasynthesis-derived myxalamids and origin of the isobutyryl-CoA starter unit of myxalamid B

Myxalamids are potent inhibitors of the eukaryotic electron transport chain produced by different myxobacteria. Here, we describe the identification of the myxalamid biosynthesis gene cluster from Myxococcus xanthus. Additionally, new myxalamids (5-13) have been obtained by mutasynthesis from bkd mutants of M. xanthus and Stigmatella aurantiaca. Moreover, as these bkd mutants are still able to produce myxalamid B (2), the origin of the isobutyryl-CoA (IB-CoA) starter unit required for its biosynthesis has been determined. In a M. xanthus bkd mutant, IB-CoA originates from valine, but in S. aurantiaca this starter unit is derived from alpha-oxidation of iso-odd fatty acids, thereby connecting primary and secondary metabolism