Open AccessPlaquelike Clearings Induced by Antimicrobial Agents on Lawns of Pseudomonas aeruginosa
Author(s) -
Marian W. Wolfe,
Daniel Amsterdam
Publication year - 1970
Publication title -
infection and immunity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.508
H-Index - 220
eISSN - 1070-6313
pISSN - 0019-9567
DOI - 10.1128/iai.1.2.190-194.1970
Subject(s) - tetracycline , microbiology and biotechnology , nalidixic acid , pseudomonas aeruginosa , biology , chloramphenicol , antimicrobial , bacteria , antibiotics , genetics
Plaques similar in appearance to those induced by phage were observed adjacent to chloramphenicol and tetracycline discs on Pseudomonas aeruginosa lawns used for the determination of antibiotic susceptibility. Thirteen strains were selected for study, 10 of which exhibited the plaquing phenomenon. The ability to form plaques induced by tetracycline was not related to any of the biochemical properties of the strains studied, their overall antimicrobial susceptibility pattern, or their pathological source. Some pseudomonad strains were capable of pyocin production; however, the relationship between plaque formation and pyocin production was not apparent. Supernatant fluids of resuspended plaque contents of eight strains originally demonstrating clearings could induce plaques on sensitive indicator lawns only when collected from tetracycline-induced plaque areas; supernatant fluids of the same strains could not produce clearings without previous exposure to the drug. Of the eight supernatant fluids capable of plaque induction, three were active on their homologous indicator lawns. In a subsequent survey of 95 P. aeruginosa strains, it was found that 28 isolates exhibited plaques. Of these, 17 were associated with tetracycline, 7 were associated with chloramphenicol, 3 were associated with triple sulfa; and 1 was associated with nalidixic acid.