Abstract
The effect of FL 1060, a newly described beta-lactam antibiotic, on three strains of Escherichia coli was studied. The agent showed extraordinarily high activity as judged by conventional titrations, but inoculum size, osmolality of the medium, and length of the incubation period were all found to have a marked effect on the result. Continuous turbidimetric monitoring and microscopical observation of cultures of E. coli exposed to FL 1060 showed the effect of the antibiotic to have many novel features. Exposed bacterial rods converted to spherical forms, but in a different manner from that of classical penicillin-mediated transformation. Furthermore, although FL 1060 was bactericidal for the majority of the bacterial population, a fraction not only survived its lethal action but grew in high concentrations of the agent thereby producing a phenotypically resistant population which nonetheless continued to show characteristic morphological deformities. Possible reasons for this anomalous behaviour are discussed.
Full text
PDFImages in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Greenwood D., O'Grady F. A comparison of the effects of ampicillin on Escherichia coli and proteus mirabilis. J Med Microbiol. 1969 Nov 4;2(4):435–441. doi: 10.1099/00222615-2-4-435. [DOI] [PubMed] [Google Scholar]
- Greenwood D., O'Grady F. Trimodal response of Escherichia coli and Proteus mirabilis to penicillins. Nature. 1970 Oct 31;228(5270):457–458. doi: 10.1038/228457a0. [DOI] [PubMed] [Google Scholar]
- Hartmann R., Höltje J. V., Schwarz U. Targets of penicillin action in Escherichia coli. Nature. 1972 Feb 25;235(5339):426–429. doi: 10.1038/235426a0. [DOI] [PubMed] [Google Scholar]
- Lederberg J. BACTERIAL PROTOPLASTS INDUCED BY PENICILLIN. Proc Natl Acad Sci U S A. 1956 Sep;42(9):574–577. doi: 10.1073/pnas.42.9.574. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lund F., Tybring L. 6 -amidinopenicillanic acids--a new group of antibiotics. Nat New Biol. 1972 Apr 5;236(66):135–137. doi: 10.1038/newbio236135a0. [DOI] [PubMed] [Google Scholar]
- Russell A. D., Fountain R. H. The effect of some cephalosporins on Escherichia coli. Postgrad Med J. 1970 Oct;(Suppl):43–50. [PubMed] [Google Scholar]
- Watson B. W., Gauci C. L., Blache L., O'Grady F. W. A simple turbidity cell for continuously monitoring the growth of bacteria. Phys Med Biol. 1969 Oct;14(4):555–558. doi: 10.1088/0031-9155/14/4/302. [DOI] [PubMed] [Google Scholar]