What do systematic reviews say?

Monotherapy vs combination therapy compared

Monotherapy showed no clear difference in all‐cause mortality—same beta lactam Survival compared with combination therapy compared (low certainty).

• Beta lactam antibiotic monotherapy versus beta lactam‐aminoglycoside antibiotic combination therapy for sepsis 2014 · Cochrane Headline outcomes only
  RR 0.97 [0.73, 1.3]
  13 studies · 1431 participants
  Low