Characterisation of a novel SCCmec VI element harbouring fusC in an emerging Staphylococcus aureus strain from the Arabian Gulf region.

Abiola Senok,Samar Boswihi,Peter Slickers,Stefan Monecke,Annett Reissig,Anju Nabi,Edet Udo,Darius Gawlik,Sascha D Braun,Joseph Mafofo,Elke Müller,Ralf Ehricht,Ali M Somily,Hedda Nitschke,Rania Nassar,Helmut Hotzel,Antje Ruppelt-Lorz,Rita G Sobral

doi:10.1371/journal.pone.0223985

Abstract

Fusidic acid is a steroid antibiotic known since the 1960s. It is frequently used in topical preparations, i.e., ointments, for the treatment of skin and soft tissue infections caused by Staphylococcus aureus. There is an increasing number of methicillin-resistant S. aureus (MRSA) strains that harbour plasmid-borne fusB/far1 or fusC that is localised on SCC elements. In this study we examined a series of related CC30-MRSA isolates from the Arabian Gulf countries that presented with SCCmec elements and fusC, including a variant that—to the best of our knowledge—has not yet formally been described. It consisted of a class B mec complex and ccrA/B-4 genes. The fusidic acid resistance gene fusC was present, but contrary to the previously sequenced element of HDE288, it was not accompanied by tirS. This element was identified in CC30 MRSA from Kuwait, Saudi Arabia and the United Arab Emirates that usually also harbour the Panton-Valentin leukocidin (PVL) genes. It was also identified in CC8 and ST834 isolates. In addition, further CC30 MRSA strains with other SCCmec VI elements harbouring fusC were found to circulate in the Arabian Gulf region. It can be assumed that MRSA strains with SCCmec elements that include fusC have a selective advantage in both hospital and community settings warranting a review of the use of topical antibiotics and indicating the necessity of reducing over-the-counter sale of antibiotics, including fusidic acid, without prescription.

Highlights

Within a year after of the introduction of penicillinase-resistant semi-synthetic penicillins such as methicillin, oxacillin and the first/second generation cephalosporins, methicillin-resistant Staphylococcus aureus (MRSA) was reported in the United Kingdom [1]
Acquired resistance due to fusB/far1 is commonly observed in the community acquired MRSA strain CC80-MRSA-IV that is common in Mediterranean and Middle Eastern countries [19,20,21,22,23,24,25,26]
In this work we examine a series of related MRSA isolates from Arabian Gulf countries that presented with SCCmec VI elements and fusidic acid (fusC)

Summary

Introduction

Within a year after of the introduction of penicillinase-resistant semi-synthetic penicillins such as methicillin, oxacillin and the first/second generation cephalosporins, methicillin-resistant Staphylococcus aureus (MRSA) was reported in the United Kingdom [1]. In addition to mecA or mecC, SCCmec elements include ccr recombinase genes, regulatory elements and, variably, additional genes encoding resistance to other antimicrobials, such as aminoglycosides or macrolides, and to heavy metal ions [4,5,6,7,8,9,10,11] They might contain the gene fusC encoding fusidic acid resistance [12, 13]. Point mutations in fusE, or rplF, encoding riboprotein L6 can confer resistance [17, 18] Another mechanism is related to the presence of the plasmid-borne gene fusB, known as far. A high prevalence of fusB/far nd fusC and/or a high prevalence of fusidic acid resistance suggest a similar effect in Middle Eastern/Arabian Gulf countries. This included a variant that—to the best of our knowledge—has not yet formally been described and it was characterised in detail

Material and methods

Aim

Results

Discussion