Tuberculous Pericarditis is Multibacillary and Bacterial Burden Drives High Mortality

•The antibiotic concentrations achieved in TB pericarditis fluid have up to now been unknown•The pH in pericardial fluid was alkaline, which would mean that pyrazinamide effect would be compromised.•The protein content in pericardial fluid was high, which would lead to low non-protein bound drug concentrations•The concentrations of rifampicin, ethambutol and pyrazinamide in pericardial were dramatically low and below their MICs