A child with a bloodborne Neisseria infection was treated with gentamicin.
After treatment, Neisseria could not be cultured from her
blood, indicating that the bacteria were killed. However, her symptoms
became worse. Annually, nearly half of similar patients die.
Explain why antibiotic treatment made her symptoms increase.
I think it is because the dead bacteria, which are intracellular when alive, are degraded, and their LPS (the lipid A moiety specifically) is presented on the cells to the immune system, causing an endotoxin response.
Yes – the LPS (endotoxin) release from killing all the bacteria so quickly has bad effects on your immune system, in the form of endotoxic shock. This is generally the case to at least some degree for any Gram negative bacterium, not just Neisseria or intracellular ones. As a result, such infections are treated with bacteriostatic antibiotics instead.