Bacteria from the genus Staphylococcus can cause a wide variety of disease. These range from minor skin infections and gastroenteritis to urgent medical emergencies such as toxic shock syndrome, bacterial septicaemia and fatal pneumonia. Staphylococcal disease is a persistent healthcare challenge and has been very successful in finding niches when faced by selection pressures posed by efforts to combat infectious disease such as the formation of modern hospitals, the introduction of antibiotic chemotherapies and Methicillin resistant Staphylococcus aureus (MRSA) screening programs.
Reflecting the highly diverse nature of staphylococcal disease, especially that caused by Staphylococcus aureus, the National Collection of Type Cultures (NCTC) provides strains isolated from a wide range of clinical cases. This includes British Society for Antimicrobial Chemotherapy (BSAC) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) recognised antibiotic sensitivity and resistance control strains.
One of the most high profile staphylococcal diseases is infection by MRSA, the leading cause of bacterial infection of the bloodstream and soft tissues in the developed world1. MRSA can be carried by healthy individuals (commonly via nasal carriage) and subsequently infect susceptible individuals such as those who are immunosuppressed or are made vulnerable to infection by invasive surgery. In addition to this, the mec genes that confer methicillin resistance to Staphylococcus aureus are mobile meaning they can be transferred to non-resistant bacteria, escalating the problem.
Clinical antibiotic use has generated epidemic resistant strains, firstly penicillin resistant strains in the mid-1940s, and then the first methicillin resistant strains reported in the early 1960s. Epidemic MRSA (EMRSA) strains are highly prevalent in the hospital environment. NCTC hold representatives of a number of EMRSA strains (NCTC 13131-13143) including a representative of EMRSA-15 (NCTC 13142), the most common and rapidly spreading strain encountered in hospital environments in the UK and Europe2.
An effective method of reducing the spread and incidence of infection of MRSA in hospitals is to screen those at risk and use alternative antimicrobial treatments before infection can occur. Mupirocin is used to reduce carriage in healthy individuals and although effective, over use can lead to mupirocin resistance. NCTC 13577 and NCTC 13656 are MRSA strains that are positive for the mupA gene, conferring high-level mupirocin resistance. NCTC 13656, as well as being mupirocin resistant, is associated with a pandemic lineage of MRSA which has spread to Asia to Europe3.
Even established strains of MRSA are constantly evolving. NCTC 13552, Staphylococcus aureus LGA251, has a novel mecA gene discovered using whole genome sequencing. This novel gene was subsequently detected in 51 of 80 other isolates from England, Scotland and Denmark which were previously thought to be negative for mecA4. This study highlights the importance of whole genome sequencing as a tool for use in diagnostics as well as research. The whole genome sequence for NCTC 13616, an EMRSA-15 strain, was used as a reference when investigating a 2009 MRSA outbreak in a neonatal unit. Although this study was used to investigate retroactively, data was obtained in a clinically relevant time frame, and highlighted the importance of reference genomes in outbreak investigation and understanding the population structure of clinical MRSA strains5.
Authenticated bacterial organisms provided by Public Health England’s Culture Collections are available for research purposes and diagnostic controls. The National Collection of Type Cultures’ NCTC_3000 project aims to make publicly available 3000 whole genome sequences for reference and research, to improve the nation’s health and reduce the burden of hospital acquired infections such as MRSA infection.
Follow the NCTC 3000 project on Twitter here.
Download or order NCTC’s UK Standards for Microbiology Investigations (SMI) test poster here.
1. Frank R. DeLeo, Henry F. Chambers. Reemergence of antibiotic-resistant Staphylococcus aureus in the genomics era. J Clin Invest. 2009 September 1; 119(9): 2464–2474
2. Matthew T.G. Holden, Li-Yang Hsu, Kevin Kurt, Lucy A. Weinert, Alison E. Mather, Simon R. Harris, Birgit Strommenger, Franziska Layer, Wolfgang Witte, Herminia de Lencastre, Robert Skov, Henrik Westh, Helena Žemličková, Geoffrey Coombs, Angela M. Kearns, Robert L.R. Hill, Jonathan Edgeworth, Ian Gould, Vanya Gant, Jonathan Cooke, Giles F. Edwards, Paul R. McAdam, Kate E. Templeton, Angela McCann, Zhemin Zhou, Santiago Castillo-Ramírez, Edward J. Feil, Lyndsey O. Hudson, Mark C. Enright, Francois Balloux, David M. Aanensen, Brian G. Spratt, J. Ross Fitzgerald, Julian Parkhill, Mark Achtman, Stephen D. Bentley, Ulrich Nübel. A genomic portrait of the emergence, evolution, and global spread of a methicillin-resistant Staphylococcus aureus pandemic. Genome Res. 2013 April; 23(4): 653–664.
3. Hajo Grundmann, David M. Aanensen, Cees C. van den Wijngaard, Brian G. Spratt, Dag Harmsen, Alexander W. Friedrich, the European Staphylococcal Reference Laboratory Working Group. Geographic Distribution of Staphylococcus aureus Causing Invasive Infections in Europe: A Molecular-Epidemiological Analysis. PLoS Med. 2010 January; 7(1).
4. Laura García-Álvarez, Matthew TG Holden, Heather Lindsay, Cerian R Webb, Derek FJ Brown, Martin D Curran, Enid Walpole, Karen Brooks, Derek J Pickard, Christopher Teale, Julian Parkhill, Stephen D Bentley, Giles F Edwards, E Kirsty Girvan, Angela M Kearns, Bruno Pichon, Robert LR Hill, Anders Rhod Larsen, Robert L Skov, Sharon J Peacock, Duncan J Maskell, Mark A Holmes. Meticillin-resistant Staphylococcus aureus with a novel mecA homologue in human and bovine populations in the UK and Denmark: a descriptive study. Lancet Infect Dis. 2011 August; 11(8): 595–603
5. Claudio U. Köser, B.A., Matthew T.G. Holden, Ph.D., Matthew J. Ellington, D.Phil., Edward J.P. Cartwright, M.B., B.S., Nicholas M. Brown, M.D., Amanda L. Ogilvy-Stuart, F.R.C.P., Li Yang Hsu, M.R.C.P., Claire Chewapreecha, B.A., Nicholas J. Croucher, M.A., Simon R. Harris, Ph.D., Mandy Sanders, B.Sc., Mark C. Enright, Ph.D., Gordon Dougan, Ph.D., Stephen D. Bentley, Ph.D., Julian Parkhill, Ph.D., Louise J. Fraser, Ph.D., Jason R. Betley, Ph.D., Ole B. Schulz-Trieglaff, Ph.D., Geoffrey P. Smith, Ph.D., and Sharon J. Peacock, Ph.D., F.R.C.P. Rapid Whole-Genome Sequencing for Investigation of a Neonatal MRSA Outbreak. N Engl J Med 2012; 366:2267-2275
Please confirm your country of origin from the list below.