Keywords
1. Staphylococcus aureus
2. Hemodialysis
3. Vascular Access Infections
4. Chronic Kidney Disease
5. Dialysis Patient Care
In the enduring battle against infection among hemodialysis patients, a recent 25-month prospective observational study published in BMC Nephrology has shed light on the colonization and infection rates of Staphylococcus aureus (S. aureus) within this vulnerable population. The study, which took place at an outpatient dialysis center, monitored a cohort of 86 individuals undergoing hemodialysis, revealing significant insights into the relationship between S. aureus carriage, infection, and patient mortality.
DOI: 10.1186/s12882-019-1332-z
The research team led by Matthias M. Scheuch and colleagues from the University Medicine Greifswald in Germany meticulously followed these patients, collecting blood samples, nasal swabs, and vascular access site swabs every six months to test for the presence of S. aureus. In addition to analyzing the carrier status of the bacteria, the team also investigated the specific lineages and genotypes of S. aureus strains through spa PCR and microarray-based genotyping.
Key findings from this study revealed that, on average, 40% of dialysis patients were carriers of S. aureus compared to 27% in the general population. Even more striking, 65% of patients were carriers at some point during the study, indicating a high level of intermittent colonization. Within the dialysis cohort, the most common lineage was clonal complex (CC) 8, and the identified spa type was t008, which differed from the dominant clonal complex CC30 found in the general population.
The study did not shy away from the grim realities of S. aureus infections, reporting six bloodstream infections attributed to the bacteria during the research period, which included one death. Intriguingly, the researchers identified a lower overall mortality rate in patients with a positive S. aureus carrier status than non-carriers, suggesting a potential protective or adaptive effect that warrants further investigation.
The preferential colonization of S. aureus in patients with arteriovenous (AV) fistulas over central venous catheters (CVCs) is a particularly notable finding, emphasizing the importance of vascular access choice in infection control. Patients with AV fistulas demonstrated a denser colonization in their nasal mucosa, which could influence the risk of subsequent infection.
As hemodialysis patients frequently interact with healthcare environments—dialysis centers, hospitals, and rest homes—they become prime candidates for exposure to health care-associated pathogens like S. aureus. The study’s findings corroborate the evidence that healthcare environments significantly contribute to the elevated colonization rates among this patient group.
The study was registered retrospectively with ISRCTN (ISRCTN 14385893) and compels the medical community to ponder the complex interaction between host and pathogen, the risks associated with different types of vascular access, and the surprising association between colonization and reduced mortality.
Given the scope and implications of the study, it has referenced several key works in the field. These include the following publications:
1. Mulcahy ME, McLoughlin RM. Host–bacterial crosstalk determines Staphylococcus aureus nasal colonization. Trends Microbiol. 2016;24(11):872–886. doi: 10.1016/j.tim.2016.06.012.
2. den Heijer CDJ, van Bijnen EME, Paget WJ, et al. Prevalence and resistance of commensal Staphylococcus aureus, including meticillin-resistant S aureus, in nine European countries: a cross-sectional study. Lancet Infect Dis. 2013;13(5):409–415. doi: 10.1016/S1473-3099(13)70036-7.
3. Holtfreter S, Grumann D, Balau V, et al. Molecular epidemiology of Staphylococcus aureus in the general population in Northeast Germany: results of the study of health in Pomerania (SHIP-TREND-0). J Clin Microbiol. 2016;54(11):2774–2785. doi: 10.1128/JCM.00312-16.
4. Wertheim HF, Melles DC, Vos MC, et al. The role of nasal carriage in Staphylococcus aureus infections. Lancet Infect Dis. 2005;5(12):751–762. doi: 10.1016/S1473-3099(05)70295-4.
5. Fowler VG, Jr, Olsen MK, Corey GR, et al. Clinical identifiers of complicated Staphylococcus aureus bacteremia. Arch Intern Med. 2003;163(17):2066–2072. doi: 10.1001/archinte.163.17.2066.
The findings of this comprehensive observational study contribute significantly to the understanding of S. aureus colonization and infection among hemodialysis patients. As we move forward, these insights can help shape infection prevention strategies, influence decisions on vascular access management, and ultimately improve patient outcomes in the hemodialysis community.