C-reactive protein predicts complications in community-associated S. aureus bacteraemia: a cohort study.

BACKGROUND: Staphylococcus aureus (S. aureus) bacteraemia is increasingly acquired from community settings and is associated with a mortality rate of up to 40% following complications. Identifying risk factors for complicated S. aureus bacteraemia would aid clinicians in targeting patients that benefit from expedited investigations and escalated care. METHODS: In this prospective observational cohort study, we aimed to identify risk factors associated with a complicated infection in community-onset S. aureus bacteraemia. Potential risk factors were collected from electronic medical records and included: - patient demographics, symptomology, portal of entry, and laboratory results. RESULTS: We identified several potential risk factors using univariate analysis. In a multiple logistic regression model, age, haemodialysis, and entry point from a diabetic foot ulcer were all significantly protective against complications. Conversely, an unknown entry point of infection, an entry point from an indwelling medical device, and a C-reactive protein concentration of over 161 mg/L on the day of admission were all significantly associated with complications. CONCLUSIONS: We conclude that several factors are associated with complications including already conducted laboratory investigations and portal of entry of infection. These factors could aid the triage of at-risk patients for complications of S. aureus bacteraemia.

Clinical significance of follow-up blood culture in patients with a single Staphylococcus aureus-positive blood culture.

Background: We evaluated the frequency of a positive result in follow-up blood cultures (FUBCs) and clinical outcome when FUBCs were not performed, in patients with a single Staphylococcus aureus-positive blood culture.Methods: We analyzed blood culture results in a prospective, observational cohort of patients with S. aureus bacteraemia (SAB) at a tertiary-care hospital. All adult patients with only a single positive blood culture set from at least two blood culture sets drawn at the initial SAB episode were enrolled in the study. We analyzed FUBC results performed within 5 days after bacteraemia onset and compared the characteristics and outcomes between patients with and without FUBCs.Results: Of 305 patients with a single S. aureus-positive blood culture, FUBCs were obtained in 274 (90%) and were positive in 15% (42/274), of whom 50% were afebrile. The rate of positivity of FUBCs was significantly higher in methicillin-resistant S. aureus (MRSA) than in methicillin-susceptible S. aureus (19% versus 9%, p = .03). In 190 patients with a single MRSA-positive blood culture, the demographic and clinical characteristics were similar between patients with and without FUBCs (167 versus 23). Although mortality was comparable between the two groups, relapse of SAB was significantly more frequent in patients in whom FUBCs were not performed (17% versus 2%, p = .008).Conclusions: Even if a patient has a single S. aureus-positive blood culture and no fever, FUBCs should be performed to manage the infection properly and to prevent SAB relapse.

Gender differences in the outcome of community-acquired Staphylococcus aureus bacteraemia: a historical population-based cohort study.

OBJECTIVES: Female gender has been suggested to be associated with poor outcome in patients with Staphylococcus aureus bacteraemia (SAB), but existing data remain sparse and conflicting. We investigated clinical outcomes in female and male patients with community-acquired (CA-) SAB. METHODS: Population-based medical registers were used to conduct a cohort study of all adult patients with CA-SAB in northern Denmark, 2000-2011. Thirty-day mortality after CA-SAB for female and male patients was estimated by the Kaplan-Meier method. Using Cox proportional hazards regression, we computed hazard ratios (HRs) of death according to gender, overall and stratified by age groups, co-morbidity level, and selected major diseases while adjusting for potential confounders. Moreover, we estimated 30-day prevalence proportions for SAB-associated infective endocarditis and osteomyelitis by gender. RESULTS: Among 2638 patients with CA-SAB, 1022 (39%) were female. Thirty-day mortality was 29% (n = 297) in female patients and 22% (n = 355) in male patients, yielding an adjusted HR (aHR) of 1.30 (95% CI, 1.11-1.53). This association appeared robust across age groups, whereas no consistent pattern was observed according to co-morbidity level. Compared with male patients, the prognostic impact of gender was most pronounced among female patients with diabetes (aHR 1.52; 95% CI 1.04-2.21)), and among female patients with cancer (aHR 1.40; 95% CI 1.04-1.90). The 30-day prevalence of infective endocarditis or osteomyelitis did not differ according to gender. CONCLUSION: Female patients with CA-SAB experienced increased 30-day mortality compared with male patients. Gender should be considered in the triage and risk stratification of CA-SAB patients.