Sepsis, September 16 edition

In 1,287 adults with methicillin-susceptible S. aureus bacteremia across eight countries, 90-day mortality was 15.0% with cefazolin versus 17.0% with (flu)cloxacillin, yielding a 99.2% probability of non-inferiority. Acute kidney injury occurred less frequently with cefazolin, 13.9% versus 19.6%, with a 99.7% probability of superiority.

Impact: This large international adaptive trial directly addresses a common antimicrobial choice and suggests that cefazolin can preserve efficacy while reducing nephrotoxicity. The result has immediate relevance for antibiotic selection, antimicrobial stewardship, and patients at risk of kidney injury.

Clinical Implications: For adults with methicillin-susceptible S. aureus bacteremia, cefazolin is a strong alternative to (flu)cloxacillin and may be preferred when acute kidney injury risk, dosing practicality, or tolerability are important. Local susceptibility patterns, infection source, endocarditis considerations, and allergy history remain relevant.

Future Directions: Further analyses should define which infection sources and high-risk subgroups derive the greatest renal-safety benefit, and should assess implementation across regions with different antimicrobial resistance patterns.

In a rat model of obstructive urosepsis, butyrate reduced systemic inflammatory mediators, renal injury markers, macrophage infiltration, cardiac mitochondrial injury, and intestinal barrier disruption. These effects were associated with suppression of renal NOX4, reactive oxygen species, and NF-κB activation, while combined butyrate and antibiotic therapy improved multiple physiological measures more than either treatment alone.

Impact: The study links a microbiome-derived metabolite to a defined renal oxidative-inflammatory pathway and demonstrates possible synergy with antibiotics. It provides a mechanistic rationale for adjunctive therapy aimed at limiting organ injury rather than only controlling the infection.

Clinical Implications: Butyrate should not yet be used routinely in patients with urosepsis, but the findings support translational studies of microbiome-derived metabolites as adjuncts to source control and antibiotics. Future human studies must establish dosing, safety, pharmacokinetics, and effects in heterogeneous septic populations.

Future Directions: Studies should validate the mechanism in independent animal models, identify the active butyrate exposure range, determine whether microbiota changes are causal, and test safety and efficacy in carefully designed early-phase human trials.

Across 13 observational studies, adult sepsis non-survivors had lower absolute CD4+ T-cell, CD8+ T-cell, CD3+ T-cell, and absolute lymphocyte counts than survivors. The evidence was most robust for CD4+ T cells, whereas CD8+, CD3+, and absolute lymphocyte-count estimates were more sensitive to heterogeneity, converted data, and sparse lower-risk studies; all prediction intervals crossed zero.

Impact: This synthesis clarifies which adaptive immune-cell measurements have the most reproducible association with sepsis mortality and explicitly demonstrates the uncertainty that prevents immediate biomarker adoption. It supports standardized longitudinal immune monitoring and severity-adjusted prognostic research.

Clinical Implications: Low CD4+ T-cell counts may help characterize immune dysfunction and risk in sepsis research, but routine prognostic decisions should not rely on these measurements alone. Assay standardization, timing specification, and adjustment for illness severity are necessary before clinical implementation.

Future Directions: Prospective multicenter studies should use standardized flow-cytometry protocols, prespecified sampling time points, longitudinal measurements, and severity-adjusted models to determine whether immune-cell counts improve prognostic classification or guide immunomodulatory treatment.