RT Journal Article SR Electronic(1) A1 Newsom, S. W. B.YR 1970 T1 Staphylococcal Persisters Grown From Empyema Fluid On L-Form Medium JF Journal of Medical Microbiology, VO 3 IS 4 SP 669 OP 673 DO https://doi.org/10.1099/00222615-3-4-669 PB Microbiology Society, SN 1473-5644, AB SUMMARY A case of staphylococcal empyema is presented in which resolution was slow in spite of apparently adequate therapy with cloxacillin. A relapse occurred when the drug was stopped after 2 wk because of the appearance of a rash. On two occasions while the patient was being treated with cloxacillin, large numbers of colonies of the bacterial form of Staphylococcus aureus appeared on plates of L-form medium but not on control plates without osmotic stabilisers. Relapse was associated with the re-emergence of staphylococci that could be isolated on conventional media, and a similar reversion of L-colonies made in vitro from the patient’s organism could be demonstrated on prolonged incubation. The infection was finally eradicated by erythromycin, novobiocin and drainage. It is suggested that cultures on L-form medium should be set up in any severe staphylococcal infection that fails to respond to chemotherapy and drainage, and that combined therapy with methicillin and an antibiotic that does not act on the cell wall should be considered., UL https://www.microbiologyresearch.org/content/journal/jmm/10.1099/00222615-3-4-669