Association between β-lactam exposure and clearance of bacteraemia and acute kidney injury in patients with methicillin-resistant Staphylococcus aureus bloodstream infections-a post hoc analysis of the CAMERA2 trial.

In 30 seconds

This post hoc analysis of the CAMERA2 randomized trial examined whether the timing and duration of β-lactam exposure were associated with bacteraemia clearance and acute kidney injury (AKI) in patients with methicillin-resistant Staphylococcus aureus bloodstream infection. Compared with no β-lactam, early, late, and throughout exposure were each associated with faster clearance; adjusted hazard ratios were 1.59 (1.16-2.19), 1.62 (1.14-2.31), and 1.85 (1.36-2.52), respectively. Late and throughout exposure were also associated with higher adjusted odds of AKI, whereas early exposure was not clearly associated with increased AKI.

Key findings

• Compared with no β-lactam, early exposure was associated with faster bacteraemia clearance (adjusted hazard ratio 1.59 [1.16-2.19]).
• Late and throughout β-lactam exposure were associated with faster clearance, with adjusted hazard ratios of 1.62 (1.14-2.31) and 1.85 (1.36-2.52), respectively.
• Adjusted AKI odds were higher with late exposure (OR 6.01 [1.61-29.60]) and throughout exposure (OR 7.93 [2.43-36.30]); early exposure had an OR of 1.24 (0.27-6.60).

Why it matters

The analysis highlights a potential trade-off between microbiological response and renal harm that may depend on β-lactam exposure duration. It also suggests that empiric-period exposure and continued combination treatment should not be assumed to have the same risk profile. These findings can inform interpretation of combination-therapy evidence, while remaining hypothesis-generating because they come from a post hoc analysis.

What to keep in mind

This was a post hoc analysis, and the exposure groups were not randomized comparisons; the associations therefore do not establish that β-lactam duration caused the observed outcomes.