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We describe the identification of a methicillin-resistant, high-level mupirocin-resistant Staphylococcus argenteus. The isolate (1801221) was characterized as t6675-ST2250-SCCmecIVc, and whole-genome sequencing revealed that the isolate possessed two plasmids. One plasmid (34,870 bp), designated p1_1801221 with rep23, harboured the mupirocin resistance (mupA) gene. The second plasmid (20,644 bp), assigned as p2_1801221 with rep5a and rep16, carried the resistance determinants for penicillin (blaZ) and cadmium (cadD). Phylogenetic analysis revealed that the isolate clustered with the European ST2250 lineage. The overall high similarity of both plasmids in S. argenteus with published DNA sequences of Staphylococcus aureus plasmids strongly suggests an interspecies transfer. The pathogenic potential, community and nosocomial spread, and acquisition of antibiotic resistance gene determinants, including the mupA gene by S. argenteus, highlight its clinical significance and the need for its correct identification., Finanziert durch den Open-Access-Publikationsfonds der Westfälischen Wilhelms-Universität Münster (WWU Münster).

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is a common healthcare-associated pathogen that remains a major public health concern. Sequence type 228 (ST228) was first described in Germany and spread to become a successful MRSA clone in several European countries. In 2000, ST228 emerged in Lausanne and has subsequently caused several large outbreaks. Here, we describe the evolutionary history of this clone and identify the genetic changes underlying its expansion in Switzerland. MATERIALS AND METHODS: We aimed to understand the phylogeographic and demographic dynamics of MRSA ST228/ST111 by sequencing 530 representative isolates of this clone that were collected from 14 European countries between 1997 and 2012. RESULTS: The phylogenetic analysis revealed distinct lineages of ST228 isolates associated with specific geographic origins. In contrast, isolates of ST111, which is a single locus variant of ST228 sharing the same spa type t041, formed a monophyletic cluster associated with multiple countries. The evidence points to a German origin of the sampled population, with the basal German lineage being characterized by spa type t001. The highly successful Swiss ST228 lineage diverged from this progenitor clone through the loss of the aminoglycoside-streptothricin resistance gene cluster and the gain of mupirocin resistance. This lineage was introduced first in Geneva and was subsequently introduced into Lausanne. CONCLUSION: Our results reveal the radiation of distinct lineages of MRSA ST228 from a German progenitor, as the clone spread into different European countries. In Switzerland, ST228 was introduced first in Geneva and was subsequently introduced into Lausanne.

Staphylococcus aureus is part of the common flora on the skin and mucous membranes of mammals and approximately 20–30% of humans are persistently colonized, mainly by mostly susceptible human-adapted isolates. In contrast, colonization with methicillin-resistant S. aureus is rare (approximately 1%), predominantly transient and associated with prior contact to the health care system. Additionally, in recent years livestock-associated S. aureus clones contributed to colonization in humans, especially in those working in close contact to farm animals. A considerable percentage of colonizing S. aureus isolates is equipped with enterotoxin genes. Humans carrying enterotoxigenic isolates represent a contamination source when handling food, thus generating a continuous risk of S. aureus food intoxication. Molecular characterization of isolates colonizing humans and obtained from food, respectively, enables the tracing of food-related outbreaks back to the source of food intoxication. We will summarize current knowledge about the S. aureus population colonizing humans, including those in close contact to animals and food, respectively. Additionally, we will review data on the molecular characterization of S. aureus isolates related to staphylococcal foodborne disease and the elucidation of staphylococcal foodborne outbreaks. Staphylococcal food poisoning is a common foodborne disease, mediated by the ingestion of enterotoxins produced by enterotoxigenic strains of S. aureus. For several outbreaks of foodborne S. aureus disease, colonized personnel could be identified as the source of food contamination. However, because of the widespread occurrence of enterotoxigenic strains as human colonizers and the often transient nature of colonization, the source of contamination cannot always be identified unambiguously. Therefore, compliance with hygiene measures is the most important requirement to prevent food contamination by both human colonization and environmental S. aureus reservoirs.

Im Epidemiologischen Bulletin 42/2019 berichtet das NRZ für Staphylokokken und Enterokokken über Häufigkeit, Eigenschaften und Verbreitung von MRSA in Deutschland. Trotz rückläufiger MRSA-Prävalenzen und -Inzidenzen ergibt sich im Vergleich mit den Vorjahren eine unverändert hohe Anzahl an Staphlococcus aureus-/MRSA-Einsendungen an das NRZ. Die detaillierte Analyse von Erregern, insbesondere die Erstellung eines sogenannten mikrobiellen genetischen Fingerabdrucks, ist unverzichtbar, um Ausbruchsgeschehen zu erkennen und evolutionäre Entwicklungen darzustellen. Bestimmte Ko-Resistenzen (Fluorchinolone, Makrolide) sind bei MRSA weiterhin rückläufig. Alleinig die Resistenzentwicklung gegenüber Tetracyclin zeigte einen leicht ansteigenden Trend.

Im Epidemiologischen Bulletin 42/2019 berichtet das NRZ für Staphylokokken und Enterokokken über Häufigkeit, Eigenschaften und Verbreitung von MRSA in Deutschland. Trotz rückläufiger MRSA-Prävalenzen und -Inzidenzen ergibt sich im Vergleich mit den Vorjahren eine unverändert hohe Anzahl an Staphlococcus aureus-/MRSA-Einsendungen an das NRZ. Die detaillierte Analyse von Erregern, insbesondere die Erstellung eines sogenannten mikrobiellen genetischen Fingerabdrucks, ist unverzichtbar, um Ausbruchsgeschehen zu erkennen und evolutionäre Entwicklungen darzustellen. Bestimmte Ko-Resistenzen (Fluorchinolone, Makrolide) sind bei MRSA weiterhin rückläufig. Alleinig die Resistenzentwicklung gegenüber Tetracyclin zeigte einen leicht ansteigenden Trend.

Zwischen 2006 und 2017 stiegen Einsendungen von humanen Staphylokokkenisolaten an das NRZ zur Verifizierung der Linezolidempfindlichkeit kontinuierlich an. In ~500 Fällen konnten wir eine Linezolid-Resistenz bestätigen, bei drei Vierteln der Stämme handelte es sich dabei um S. epidermidis.[zum vollständigen Text gelangen Sie über die oben angegebene URL], Bad Honnef-Symposium 2018