The association between pathogen factors and clinical outcomes in patients with Staphylococcus aureus bacteraemia in a tertiary hospital, Cape Town

dc.contributor.authorAbdulgadera, Shima M.en_ZA
dc.contributor.authorVan Rijswijk, Amikeen_ZA
dc.contributor.authorWhitelawa, Andrewen_ZA
dc.contributor.authorNewton-Foota, Maeen_ZA
dc.date.accessioned2020-07-16T05:46:01Z
dc.date.available2020-07-16T05:46:01Z
dc.date.issued2019-11-29
dc.descriptionCITATION: Abdulgadera, S. M. 2020. The association between pathogen factors and clinical outcomes in patients with Staphylococcus aureus bacteraemia in a tertiary hospital, Cape Town. International Journal of Infectious Diseases, 91:111-118, doi:10.1016/j.ijid.2019.11.032.
dc.descriptionThe original publication is available at https://www.ijidonline.com
dc.descriptionPublication of this article was funded by the Stellenbosch University Open Access Fund
dc.description.abstractBackground: Staphylococcus aureus is a serious pathogen, able to cause life-threatening infections such as bacteraemia. The association between S. aureus microbial characteristics and clinical outcomes is under- investigated in African settings. This study aimed to determine the molecular epidemiology and virulence characteristics of S. aureus isolates from bacteraemic patients at Tygerberg Hospital, South Africa, and to investigate the associations between pathogen characteristics and clinical outcomes. Methods: This study included 199 S. aureus isolates collected from blood cultures between February 2015 and March 2017. Methicillin resistance was determined using disc diffusion and all resistant isolates were further characterized by staphylococcal cassette chromosome mec (SCCmec) typing. Genotyping was done using spa and agr typing, and agr functionality was assessed using the phenotypic d-haemolysin assay. Logistic regression models were performed to describe the associations between strain characteristics and the clinical outcomes methicillin resistance, in-hospital mortality, and length of stay (LOS). Results: Of the 199 S. aureus isolates collected, 27% were MRSA, and the overall crude in-hospital mortality rate was 29%. Seventy-three different spa types were identified, including seven new types. Agr I was the most common type, in 99 (49.7%) isolates, followed by agr II, III, and IV in 57 (28.6%), 37 (18.6%), and six (3%) isolates, respectively. Agr dysfunctionality was observed in 25 (13%) isolates, mostly belonging to spa-clonal complex (CC) 012. Methicillin resistance was significantly associated with hospital-acquired infection (odds ratio (OR) 4.77, 95% confidence interval (CI) 2.09–10.87). A significant increase in mortality was observed with increasing age (OR 7.48, 95% CI 2.82–19.8) and having a hospital-acquired infection (OR 2.26, 95% CI 1.12–4.55). S. aureus strains with a functional agr system showed an association with longer duration of stay (OR 1.66, 95% CI 0.93–2.99). Conclusions: We report the lowest MRSA prevalence at Tygerberg Hospital for the past 10 years, and agr dysfunctionality was shown to be driven by a certain genotype, spa-CC012. Despite the limited available clinical data, the study provided insights into associations between S. aureus epidemiology and agr-related virulence characteristics, and clinical outcomes.en_ZA
dc.description.urihttps://www.ijidonline.com/article/S1201-9712(19)30472-2/fulltext
dc.description.versionPublisher's version
dc.format.extent8 pagesen_ZA
dc.identifier.citationAbdulgadera, S. M. 2020. The association between pathogen factors and clinical outcomes in patients with Staphylococcus aureus bacteraemia in a tertiary hospital, Cape Town. International Journal of Infectious Diseases, 91:111-118, doi:10.1016/j.ijid.2019.11.032
dc.identifier.issn1878-3511 (online)
dc.identifier.issn1201-9712 (print)
dc.identifier.otherdoi:10.1016/j.ijid.2019.11.032
dc.identifier.urihttp://hdl.handle.net/10019.1/108708
dc.language.isoen_ZAen_ZA
dc.publisherElsevier on behalf of International Society for Infectious Diseasesen_ZA
dc.rights.holderAuthors retain copyrighten_ZA
dc.subjectStaphylococcus aureusen_ZA
dc.subjectPathogenic bacteriaen_ZA
dc.subjectBacteraemiaen_ZA
dc.subjectGenetic regulationen_ZA
dc.subjectMolecular epidemiologyen_ZA
dc.titleThe association between pathogen factors and clinical outcomes in patients with Staphylococcus aureus bacteraemia in a tertiary hospital, Cape Townen_ZA
dc.typeArticleen_ZA
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