20 Introduction to Staphylococcus aureus
- State some of the main features of Staphylococcus aureus.
- Recall the main cause of public health concern related to this species.
20.1 Staphylococcus aureus
Staphylococcus aureus is an important human pathogen that colonises approximately 30% of the population. It is a major cause of multiple infections with varying degrees of severity including skin and soft tissue, bone and joint, endocarditis, device and prosthesis, line-related, pneumonia, and bacteraemia. Mortality from bacteraemia is reported at approximately 30% (Bai 2022) with approximately 14,000 cases from 2022 to 2023 (UKHSA 2023). Antimicrobial drug resistance (AMR) is an important factor in increasing mortality resulting from S. aureus infections. In the global burden of disease study from 2019, S. aureus was the second highest contributing pathogen to AMR-related deaths (Lancet 2022). Meticillin resistant S. aureus (MRSA) is a primary concern of resistance amongst S. aureus infections and accounted for the pathogen-drug combination, across all bacteria, with the highest attributable deaths, whilst resulting in a higher mortality when compared to methicillin sensitive S. aureus (MSSA) (UKHSA 2023).
Genomic epidemiological studies over the last two decades have provided significant insights into the transmission dynamics of S. aureus and aided targeted control strategies. Whole-genome sequences from S. aureus isolates derived from hospitals and the community have provided insights outbreaks related to critical care wards, care homes, intravenous drug user networks and schools (Harris, 2013, Coll 2017, Marks 2021, van Tonder 2023). It has helped detail the emergence of human-adapted clades, such as CC398, facilitated a one-health approach to understanding transmission, and identified key virulence traits (Young 2012, Uhlemann 2017, Larsen 2022).
There is an increasing body of evidence that routine use of whole-genome sequencing can aid infection prevention control and public health decision making, and this is being increasingly investigated and implemented (Durand 2018). That said, there is a significant disparity in sequences generated between regions and an under-representation of sequences from MSSA, which can bias our understanding of the population dynamics and evolutionary selection pressures shaping S. aureus populations.
20.2 Course dataset
For this course we’re going to analyse 30 isolates collected as part of a citizen science project that aimed to identify links between self-reported social networks and genome-linked transmission of S. aureus in two Cambridgeshire schools (van Tonder 2023).
20.3 Summary
- Staphylococcus aureus is a bacterium species that is a part of the human microbiota. However, it can also cause a range of infections, from minor skin infections to more serious conditions like pneumonia, endocarditis, and sepsis.
- Methicillin-Resistant Staphylococcus aureus (MRSA) are of primary concern, as they are resistant to common antibiotics such as methicillin.
- Genome sequencing and assembly of this species can aid in identifying clonal clusters and presence of antimicrobial resistance genes.
References
Bai AD, Lo CKL, Komorowski AS, Suresh M, Guo K, Garg A, et al. Staphylococcus aureus bacteraemia mortality: a systematic review and meta-analysis. Clin Microbiol Infect. 2022. DOI
UKHSA. Annual epidemiological commentary: Gram-negative, MRSA, MSSA bacteraemia and CDI infections, up to and including financial year 2022 to 2023. 2023. Link
Antimicrobial Resistance Collaborators. Global burden of bacterial antimicrobial resistance in 2019: a systematic analysis. Lancet. 2022. DOI
UKHSA. 30 day all-cause mortality following MRSA, MSSA and Gram-negative bacteraemia and C. difficile infections: 2021 to 2022 report. 2023. Link
Coll F, Harrison EM, Toleman MS, Reuter S, Raven KE, Blane B, et al. Longitudinal genomic surveillance of MRSA in the UK reveals transmission patterns in hospitals and the community. Sci Transl Med. 2017. DOI
Harris SR, Cartwright EJ, Torok ME, Holden MT, Brown NM, Ogilvy-Stuart AL, et al. Whole-genome sequencing for analysis of an outbreak of meticillin-resistant Staphylococcus aureus: a descriptive study. Lancet Infect Dis. 2013. DOI
Marks LR, Calix JJ, Wildenthal JA, Wallace MA, Sawhney SS, Ransom EM, et al. Staphylococcus aureus injection drug use-associated bloodstream infections are propagated by community outbreaks of diverse lineages. Commun Med (Lond). 2021. DOI
van Tonder AJ, McCullagh F, McKeand H, Thaw S, Bellis K, Raisen C, et al. Colonization and transmission of Staphylococcus aureus in schools: a citizen science project. Microb Genom. 2023. DOI
Uhlemann AC, McAdam PR, Sullivan SB, Knox JR, Khiabanian H, Rabadan R, et al. Evolutionary Dynamics of Pandemic Methicillin-Sensitive Staphylococcus aureus ST398 and Its International Spread via Routes of Human Migration. mBio. 2017. DOI
Larsen J, Raisen CL, Ba X, Sadgrove NJ, Padilla-Gonzalez GF, Simmonds MSJ, et al. Emergence of methicillin resistance predates the clinical use of antibiotics. Nature. 2022. DOI
Young BC, Golubchik T, Batty EM, Fung R, Larner-Svensson H, Votintseva AA, et al. Evolutionary dynamics of Staphylococcus aureus during progression from carriage to disease. Proc Natl Acad Sci U S A. 2012. DOI
Durand G, Javerliat F, Bes M, Veyrieras JB, Guigon G, Mugnier N, et al. Routine Whole-Genome Sequencing for Outbreak Investigations of Staphylococcus aureus in a National Reference Center. Front Microbiol. 2018. DOI