The Journal of Medical Microbiology, Vol 11, Issue 1 33-45, Copyright © 1978 by Society for General Microbiology
Human infections with thymine-requiring bacteria
R. Maskell, O. A. Okubadejo, R. H. Payne and L. Pead
Clinical details are presented of 16 patients from whom thymine-requiring
(thy-) mutants of pathogenic organisms were isolated; all had been treated
with co-trimoxazole. The urine of six patients infected with thy- mutants
contained levels of a thymine-like compound sufficient to support their
growth. This might be the result either of the breakdown of pus cells or of
thymine production by living bacteria that persist in stones or scar
tissue, a suggestion supported by the observation of mutant growth "in
satellitism" in vitro. Since 1975 we have isolated mutants from patients
who have had short courses of co-trimoxazole, in contrast to those we
reported upon previously, all except one of whom had had long courses. We
are now isolating thy- mutants more frequently than hitherto. Secondary
mutations to a low thymine requirement may now be occurring more rapidly,
thereby allowing more mutant organisms to survive. The clinical
significance of infection with thy- mutants is not yet clear, but evidence
is accumulating that they are pathogenic. Alternative chemotherapy is
suggested for patients from whom such mutants have been isolated.
