Predictors of septic shock in patients with methicillin-resistant Staphylococcus aureus bacteremia

Prompt Identification of Sepsis on Hospital Floors: Are Healthcare Professionals Ready for the Implementation of the Hour-1 Bundle?

Early intervention in sepsis management with recognized therapeutic targets may be effective in lowering sepsis-related morbidity and mortality, although this necessitates timely identification of sepsis by healthcare professionals. The present study aimed to assess knowledge levels, attitudes, and agreement among physicians regarding the Surviving Sepsis Campaign (SSC) guidelines (more specifically, the Hour-1 bundle). A quantitative, descriptive, cross-sectional study was conducted among physicians working in different clinical settings in Karachi, Pakistan, using a self-administered questionnaire. The mean cumulative knowledge score of the respondents towards SSC was 6.8 ± 2.1 (out of 10), where a total of n = 127 respondents (51.62%) had a strong understanding of the SSC guidelines, compared to n = 78 (31.7%) and n = 41 (16.7%) respondents with fair and inadequate knowledge, respectively. The majorly known bundle elements by the respondents were to administer broad-spectrum antibiotics (89.8%, n = 221), the need for taking blood cultures before administering antibiotics (87.8%, n = 216), and measurement of blood lactate levels (75.6%, n = 186). Experienced physicians were more likely to use norepinephrine as the first-choice vasopressor (p < 0.001). Female respondents were more likely to consider the duration of antibiotic therapy to be determined according to the site of infection, the microbiological etiology, the patient’s response to treatment, and the likelihood of achieving adequate source control (p = 0.001). The current study concluded that respondents had an optimistic approach and frequently practice in accordance with the SSC guidelines, while some respondents were not up to date with the most recent guidelines. There is a need for further interventions and continuous medical education to encourage physicians towards appropriate use of the recommended guiding principles for improving treatment outcomes in sepsis patients.

Delay in Antibiotic Administration Is Associated With Mortality Among Septic Shock Patients With Staphylococcus aureus Bacteremia

OBJECTIVES

The relationship between the timing of antibiotics and mortality among septic shock patients has not been examined among patients specifically with Staphylococcus aureus bacteremia.

DESIGN

Retrospective analysis of a Veterans Affairs S. aureus bacteremia database.

SETTING

One-hundred twenty-two hospitals in the Veterans Affairs Health System.

PATIENTS

Patients with septic shock and S. aureus bacteremia admitted directly from the emergency department to the ICU from January 1, 2003, to October 1, 2015, were evaluated.

INTERVENTIONS

Time to appropriate antibiotic administration and 30-day mortality.

MEASUREMENTS AND MAIN RESULTS

A total of 506 patients with S. aureus bacteremia and septic shock were included in the analysis. Thirty-day mortality was 78.1% for the entire cohort and was similar for those participants with methicillin-resistant S. aureus and methicillin-sensitive S. aureus bacteremia. Our multivariate analysis revealed that, as compared with those who received appropriate antibiotics within 1 hour after emergency department presentation, each additional hour that passed before appropriate antibiotics were administered produced an odds ratio of 1.11 (95% CI, 1.02-1.21) of mortality within 30 days. This odds increase equates to an average adjusted mortality increase of 1.3% (95% CI, 0.4-2.2%) for every hour that passes before antibiotics are administered.

CONCLUSIONS

The results of this study further support the importance of prompt appropriate antibiotic administration for patients with septic shock. Physicians should consider acting quickly to administer antibiotics with S. aureus coverage to any patient suspected of having septic shock.

Characterization of patients with bacteremia by methicillin-resistant Staphylococcus aureus in a high-complexity military hospital

Introduction: In Colombia, there are about 500,000 members in the national armed forces who consult military health institutions. In this population, methicillin-resistant Staphylococcus aureus (MRSA) has become a high-incidence pathogen. Objective: The aim of this study was to characterize patients with MRSA bacteremia in the Hospital Militar Central between 2012 and 2015. Materials and methods: This was an observational descriptive study with a retrospective review of clinical histories of hospitalized patients older than 18 years of age with positive blood cultures for methicillin-resistant S. aureus. The identification of the patients was made using the Whonet system, version 5.6. Results: From cultures positive for S. aureus, 24.8% were methicillin-resistant strains, with a higher prevalence in active military personnel. A similar frequency was observed for community-acquired MRSA bacteremias and those acquired at the hospital, with the community phenotype being the most frequent in both groups. The main infectious focus related to the development of bacteremia was soft tissue, followed by pulmonary tissue. There were higher complication rates in nosocomial bacteremias; 34.9% of the patients had prolonged stays attributable to complications triggered by the bacteremia. Conclusions: Active military personnel was the most affected population by MRSA, with a similar frequency in community-acquired and nosocomial bacteremias. The main infectious focus was soft tissue. Taking into account these data, studies that establish the prevalence of skin infections by MRSA should be carried out.

Comparative effectiveness of beta-lactams versus vancomycin for treatment of methicillin-susceptible Staphylococcus aureus bloodstream infections among 122 hospitals

BACKGROUND

Previous studies indicate that vancomycin is inferior to beta-lactams for treatment of methicillin-susceptible Staphylococcus aureus (MSSA) bloodstream infections. However, it is unclear if this association is true for empiric and definitive therapy. Here, we compared beta-lactams with vancomycin for empiric and definitive therapy of MSSA bloodstream infections among patients admitted to 122 hospitals.

METHODS

This retrospective cohort study included all patients admitted to Veterans Affairs hospitals from 2003 to 2010 who had positive blood cultures for MSSA. Hazard ratios (HR) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression. Empiric therapy was defined as starting treatment 2 days before and up to 4 days after the first MSSA blood culture was collected. Definitive therapy was defined as starting treatment between 4 and 14 days after the first positive blood culture was collected.

RESULTS

Patients who received empiric therapy with a beta-lactam had similar mortality compared with those who received vancomycin (HR, 1.03; 95% CI, .89-1.20) after adjusting for other factors. However, patients who received definitive therapy with a beta-lactam had 35% lower mortality compared with patients who received vancomycin (HR, 0.65; 95% CI, .52-.80) after controlling for other factors. The hazard of mortality decreased further for patients who received cefazolin or antistaphylococcal penicillins compared with vancomycin (HR, 0.57; 95% CI, .46-.71).

CONCLUSIONS

For patients with MSSA bloodstream infections, beta-lactams are superior to vancomycin for definitive therapy but not for empiric treatment. Patients should receive beta-lactams for definitive therapy, specifically antistaphylococcal penicillins or cefazolin.

Shedding of tumor necrosis factor receptor 1 induced by protein A decreases tumor necrosis factor alpha availability and inflammation during systemic Staphylococcus aureus infection

Staphylococcus aureus infections are an important public health concern due to their increasing incidence and high rates of mortality. The success of S. aureus as a pathogen is highly related to its enormous capacity to evade the host immune response. The critical role of tumor necrosis factor alpha (TNF-α) in the initial host defense against systemic staphylococcal infection has been demonstrated in experimental models and may partially explain the lack of significant benefits observed in clinical trials attempting to neutralize this cytokine in septic patients. S. aureus protein A plays a key role in regulating inflammation through its ability to bind and signal through the TNF-α receptor 1 (TNFR1). In this study, we demonstrate that S. aureus, via protein A-mediated signaling, induces early shedding of TNFR1, which precedes the secretion of TNF-α in vitro and in vivo. The results obtained using a protein A-deficient mutant and tnfr1(-/-) mice strongly suggest that the increased levels of soluble TNFR1 present during experimental S. aureus infection may neutralize circulating TNF-α and impair the host inflammatory response. Early shedding of TNFR1 induced by protein A may constitute a novel mechanism by which S. aureus subverts the host immune response.