Molecular Epidemiology of Staphylococcus aureus Bacteremia: Association of Molecular Factors With the Source of Infection

Abstract

Staphylococcus aureus bacteremia (SAB) is associated with high morbidity and mortality, which varies depending on the source of infection. Nevertheless, the global molecular epidemiology of SAB and its possible association with specific virulence factors remains unclear. Using DNA microarrays, a total of 833 S. aureus strains (785 SAB and 48 colonizing strains) collected in Spain over a period of 15 years (2002–2017) were characterized to determine clonal complex (CC), agr type and repertoire of resistance and virulence genes in order to provide an epidemiological overview of CCs causing bloodstream infection, and to analyze possible associations between virulence genes and the most common sources of bacteremia. The results were also analyzed by acquisition (healthcare-associated [HA] and community-acquired [CA]), methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) strains, and patient age (adults vs. children). Our results revealed high clonal diversity among SAB strains with up to 28 different CCs. The most prevalent CCs were CC5 (30.8%), CC30 (20.3%), CC45 (8.3%), CC8 (8.4%), CC15 (7.5%), and CC22 (5.9%), which together accounted for 80% of all cases. A higher proportion of CC5 was found among HA strains than CA strains (35.6 vs. 20.2%, p < 0.001). CC5 was associated with methicillin resistance (14.7 vs. 79.4%, p < 0.001), whereas CC30, CC45, and CC15 were correlated with MSSA strains (p < 0.001). Pathogen-related molecular markers significantly associated with a specific source of bacteremia included the presence of sea, undisrupted hlb and isaB genes with catheter-related bacteremia; sed, splE, and fib genes with endocarditis; undisrupted hlb with skin and soft tissue infections; and finally, CC5, msrA resistance gene and hla gene with osteoarticular source. Our study suggests an association between S. aureus genotype and place of acquisition, methicillin resistance and sources of bloodstream infection, and provides a valuable starting point for further research insights into intrinsic pathogenic mechanisms involved in the development of SAB.

Molecular characterization of methicillin-resistant Staphylococcus aureus clinical strains from the endotracheal tubes of patients with nosocomial pneumonia

“…The molecular epidemiology of MRSA in bloodstream infections has been described previously, but less frequently in respiratory infections contracted in the ICU [27,28]. CC22 is one of the largest circulating clonal complexes associated with hospital-acquired MRSA in Europe (UK) and Asia (Kuala Lumpur, China) [11,29], while studies of nosocomial pneumonia indicate that CC5 is associated with MRSA strains originating mostly from the US, Europe (Portugal), Asia (China), Africa (Algeria) and Latin America (Argentina and Chile) [18,19,30,31].…”

Antimicrobial Resistance and Molecular Epidemiology of Staphylococcus aureus Causing Bloodstream Infections at Ruijin Hospital in Shanghai from 2013 to 2018

“…It has been suggested that CC5 has become an increasingly frequent cause of MRSA infections as well as bacteremia acquired by hospitalized patients from some other reports and that healthcare exposure is no longer a discriminator of USA100 vs USA300 infections [28][29][30] . An analysis of SAB conducted in www.nature.com/scientificreports www.nature.com/scientificreports/ Spain over 15 years (2002-2017) revealed that CC5 was the most prevalent CC and the proportion of CC5 among healthcare-associated S. aureus isolates was higher than that among community-associated S. aureus isolates, and CC5 was much more associated with methicillin resistance 4 . Simultaneously, CC5 MRSA was also prevalent in bloodstream infections in nine Latin American countries except in Colombia and Ecuador 29 .…”

“…The vast majority of patients with LA-MRSA CC398 BSIs had no history of exposure to livestock, which is similar to the ratio observed for other types of MRSA, and it demonstrates that the increase of LA-MRSA CC398 BSIs was accompanied by a large increase of LA-MRSA CC398 SSTIs and the expansion of porcine reservoir 32 . CC398 S. aureus resulted in an increasing incidence of bloodstream infections tst (21),sea (4),seb (1),sec (21),seg (24),seh (15),sei (22) tst (1), sec (1), seg (1), sei (1) sed (3), seg (3), seh (1),sei (3), sej (2) 764 12 2 II (8) IV (2) t002 (8) t002 (2) t002 (2) tst (3),seb (2),sec (3), seg (8),seh (8),sei (8) tst (2), sec (2), seg (2), seh (2), sei (2) sec (1), sed (1), seg (2), seh (1), sei (2) www.nature.com/scientificreports www.nature.com/scientificreports/ in a French hospital between 2010 and 2017 as well; the prevalence rate of CC398 isolates among S. aureus BSIs increased from 3.6% in 2010 to 20.2%in 2017 (P < 0.05) 33 . CC398 MRSA emerged but remains very sparse and CC398 MSSA disseminates in the community as suggested.…”

“…Therefore, it is deeply needed to monitor the extraordinary cloning of human adaptive S. aureus like CC398 and genomic studies might can figure out the determinants of its diffusion. (1) t037 (1) sea (1) II (39) ST5 (24) t1818 (1),t2460 (9),t264 (2),t311 (3),t450 (1),t458 (1),t601 (1), t9353 (2),t9363 (4) tst (21),sea (4),seb (1),sec (21),seg (24),seh (15),sei (22) ST764 (8) t002 (8) tst (3),seb (2),sec (3),seg (8),seh (8),sei (8) ST1801 (4) t030 (1),t037 (2),t421 (1) sea (4),seh (2) ST3066 (2) t5076 (2) tst(2),sec (2),seg (2),sei (2) ST59 (1) t437(1) sea (1) IV (4) ST764 (2) t002 (2) tst(2),sec (2),seg (2),seh (2),sei (2) ST5 1 Table 4. SCCmec types of 53 MRSA isolates causing bloodstream infections from 2013 to 2018.…”

The Continuing Evolution of Community-Associated MRSA ST93-IV in Australia

“…The hsdM gene has recently been shown to be a hotspot for chromosome rearrangements in staphylococcus causing phenotype switching associated with persistent infections (17). The clfA gene, which mediates staphylococcal binding to brin coated surfaces, has previously been linked to bacteraemia (18).…”