Demonstration of pathogenic bacteria in "sterile" inflammatory exudates

One hundred and twenty-seven exudates from inflammatory processes, judged sterile after incubation on standard isolation media, were further investigated. This involved the exclusion of slow-growing strains by a further 48 hours incubation of the primary plates and subcultures from hypertonic broth that had been inoculated concurrently with the initial cultures. Over 80% of otherwise sterile exudates grew presumptive pathogens only after passage through the hypertonic broth and no further isolations resulted from extended incubation of the primary cultures. A history of current, or recent, antibiotic therapy commonly accompanied the demonstration of these aberrant strains and clinical remission of symptoms usually followed fresh antibiotic therapy directed solely against the revertant isolates.