Molecular Epidemiology of Staphylococcus aureus in the General Population in Northeast Germany: Results of the Study of Health in Pomerania (SHIP-TREND-0).

Silva Holtfreter,Barbara M Bröker,Christiane Cuny,Stephanie S Bauerfeind,Birgit Walther,Nicole Haasler,Chi Hai Vu,Paula Döring,Annette Barwich,Wolfgang Witte,Dorothee Grumann,Ivo Steinmetz,Kristin Henselin,Susanne Westphal,Veronika Balau,Julia Kolata,Henry Völzke,Sophie Nowotny,Erika Friebe,Birte Holtfreter,Dörte Radke,Thomas Kocher,Patricia Trübe,Katrin Gaardbo Kuhn ,Kirk H Schulz ,Sebastian Schulz ,André Göhler ,Hans J Grabe ,Stefan Weiß

doi:10.1128/jcm.00312-16

Abstract

Population-based studies on Staphylococcus aureus nasal colonization are scarce. We examined the prevalence, resistance, and molecular diversity of S. aureus in the general population in Northeast Germany. Nasal swabs were obtained from 3,891 adults in the large-scale population-based Study of Health in Pomerania (SHIP-TREND). Isolates were characterized using spa genotyping, as well as antibiotic resistance and virulence gene profiling. We observed an S. aureus prevalence of 27.2%. Nasal S. aureus carriage was associated with male sex and inversely correlated with age. Methicillin-resistant S. aureus (MRSA) accounted for 0.95% of the colonizing S. aureus strains. MRSA carriage was associated with frequent visits to hospitals, nursing homes, or retirement homes within the previous 24 months. All MRSA strains were resistant to multiple antibiotics. Most MRSA isolates belonged to the pandemic European hospital-acquired MRSA sequence type 22 (HA-MRSA-ST22) lineage. We also detected one livestock-associated MRSA ST398 (LA-MRSA-ST398) isolate, as well as six livestock-associated methicillin-susceptible S. aureus (LA-MSSA) isolates (clonal complex 1 [CC1], CC97, and CC398). spa typing revealed a diverse but also highly clonal S. aureus population structure. We identified a total of 357 spa types, which were grouped into 30 CCs or sequence types. The major seven CCs (CC30, CC45, CC15, CC8, CC7, CC22, and CC25) included 75% of all isolates. Virulence gene patterns were strongly linked to the clonal background. In conclusion, MSSA and MRSA prevalences and the molecular diversity of S. aureus in Northeast Germany are consistent with those of other European countries. The detection of HA-MRSA and LA-MRSA within the general population indicates possible transmission from hospitals and livestock, respectively, and should be closely monitored.

Highlights

Population-based studies on Staphylococcus aureus nasal colonization are scarce
14.4% of the study participants stayed in a hospital within the previous 12 months, 21.3% frequently visited a hospital, nursing home, retirement home, or hospice during the previous 24 months, and 7% were employed in the medical sector
There was no association between S. aureus carriage and exposure to health care environments

Summary

Introduction

Resistance, and molecular diversity of S. aureus in the general population in Northeast Germany. MSSA and MRSA prevalences and the molecular diversity of S. aureus in Northeast Germany are consistent with those of other European countries. The core genome is highly conserved across S. aureus strains and comprises genes associated with central metabolism and other housekeeping functions. The core variable genome is strictly linked to particular clonal lineages and includes regulators of virulence gene expression, e.g., the accessory gene regulator (agr), and surface proteins [11]. Patterns of MGEs (e.g., plasmids, phages, and pathogenicity and genomic islands) are highly varied between S. aureus isolates but are often associated with particular clonal lineages [11, 12]. MGEs carry a variety of resistance and virulence genes, encoding, for example, superantigens (SAgs), exfoliative toxins, and pore-forming toxins

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