Identification of a PVL-negative SCCmec-IVa sublineage of the methicillin-resistant Staphylococcus aureus CC80 lineage: understanding the clonal origin of CA-MRSA

TY - JOUR

T1 - Identification of a PVL-negative SCCmec-IVa sublineage of the methicillin-resistant Staphylococcus aureus CC80 lineage

T2 - understanding the clonal origin of CA-MRSA

AU - Edslev, S. M.

AU - Westh, H.

AU - Andersen, P. S.

AU - Skov, R.

AU - Kobayashi, N.

AU - Bartels, M. D.

AU - Vandenesch, F.

AU - Petersen, A.

AU - Worning, P.

AU - Larsen, A. R.

AU - Stegger, M.

PY - 2018

Y1 - 2018

N2 - Objectives: Community-acquired (CA) methicillin-resistant Staphylococcus aureus (MRSA) isolates belonging to clonal complex 80 (CC80) are recognized as the European CA-MRSA. The prevailing European CA-MRSA clone carries a type IVc staphylococcal cassette chromosome mec (SCCmec) and expresses Panton-Valentine leukocidin (PVL). Recently, a significant increase of PVL-negative CC80 MRSA has been observed in Denmark. The aim of this study was to examine their genetics and epidemiology, and to compare them to the European CA-MRSA clone in order to understand the emergence of PVL-negative CC80 MRSA. Methods: Phylogenetic analysis of the CC80 S. aureus lineage was conducted from whole-genome sequences of 217 isolates (23 methicillin-susceptible S. aureus and 194 MRSA) from 22 countries. All isolates were further genetically characterized in regard to resistance determinants and PVL carriage, and epidemiologic data were obtained for selected isolates. Results: Phylogenetic analysis revealed the existence of three distinct clades of the CC80 lineage: (a) an methicillin-susceptible S. aureus clade encompassing Sub-Saharan African isolates (n = 13); (b) a derived clade encompassing the European CA-MRSA SCCmec-IVc clone (n = 185); and (c) a novel and genetically distinct clade encompassing MRSA SCCmec-IVa isolates (n = 19). All isolates in the novel clade were PVL negative, but carried remnant parts (8–12 kb) of the PVL-encoding prophage ΦSa2 and were susceptible to fusidic acid and kanamycin/amikacin. Geospatial mapping could link these isolates to regions in the Middle East, Asia and South Pacific. Conclusions: This study reports the emergence of a novel CC80 CA-MRSA sublineage, showing that the CC80 lineage is more diverse than previously assumed.

AB - Objectives: Community-acquired (CA) methicillin-resistant Staphylococcus aureus (MRSA) isolates belonging to clonal complex 80 (CC80) are recognized as the European CA-MRSA. The prevailing European CA-MRSA clone carries a type IVc staphylococcal cassette chromosome mec (SCCmec) and expresses Panton-Valentine leukocidin (PVL). Recently, a significant increase of PVL-negative CC80 MRSA has been observed in Denmark. The aim of this study was to examine their genetics and epidemiology, and to compare them to the European CA-MRSA clone in order to understand the emergence of PVL-negative CC80 MRSA. Methods: Phylogenetic analysis of the CC80 S. aureus lineage was conducted from whole-genome sequences of 217 isolates (23 methicillin-susceptible S. aureus and 194 MRSA) from 22 countries. All isolates were further genetically characterized in regard to resistance determinants and PVL carriage, and epidemiologic data were obtained for selected isolates. Results: Phylogenetic analysis revealed the existence of three distinct clades of the CC80 lineage: (a) an methicillin-susceptible S. aureus clade encompassing Sub-Saharan African isolates (n = 13); (b) a derived clade encompassing the European CA-MRSA SCCmec-IVc clone (n = 185); and (c) a novel and genetically distinct clade encompassing MRSA SCCmec-IVa isolates (n = 19). All isolates in the novel clade were PVL negative, but carried remnant parts (8–12 kb) of the PVL-encoding prophage ΦSa2 and were susceptible to fusidic acid and kanamycin/amikacin. Geospatial mapping could link these isolates to regions in the Middle East, Asia and South Pacific. Conclusions: This study reports the emergence of a novel CC80 CA-MRSA sublineage, showing that the CC80 lineage is more diverse than previously assumed.

KW - Antibiotic resistance

KW - CA-MRSA

KW - Epidemiology

KW - Evolution

KW - Genetics

KW - Phylogeny

KW - SCCmec

U2 - 10.1016/j.cmi.2017.06.022

DO - 10.1016/j.cmi.2017.06.022

M3 - Journal article

C2 - 28668467

AN - SCOPUS:85027719634

SN - 1198-743X

VL - 24

SP - 273

EP - 278

JO - Clinical Microbiology and Infection

JF - Clinical Microbiology and Infection

IS - 3

ER -