This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Friend, P. L. Articles by Slade, H. D. Search for Related Content PubMed PubMed Citation Articles by Friend, P. L. Articles by Slade, H. D.

Effect of Resistance to Chloramphenicol on Bacteriophage Sensitivity of Group A Streptococci ¹

^a Department of Microbiology, Northwestern University Medical School, Chicago, Illinois

ABSTRACT

Several phage hosts of group A streptococci became resistant to lysis by bacteriophage as a consequence of having acquired the ability to grow in the presence of chloramphenicol. The phage was adsorbed to the streptococcal cell, and P³²-labeling of the phage showed that the phage genome penetrated the chloramphenicol (CM)- resistant cells as it did the parent cells. However, artificial lysis of the infected CM-resistant cells with chloroform or enzymes revealed no intracellular mature phage particles. Lysates of infected CM-resistant cells contained no phage-related antigenic materials which possessed serum-blocking power, although they were readily detected in lysates of infected parent cells. The CM-resistant cells were not lysogenized by the phage. Only cells resistant to more than 10 µg/ml of chloramphenicol were resistant to phage, and this threshold effect was taken as an indication of at least two different loci of chloramphenicol resistance on the streptococcal genome. Strains resistant to high levels of other antibiotics, such as streptomycin and erythromycin, showed no resistance to lysis by phage. Evidence indicated that the mutant cells were deficient in an essential function associated with the phage genome.

² Present address: Department of Microbiology, College of Medicine, University of Cincinnati, Cincinnati, Ohio. Predoctoral trainee of the Institute of General Medical Sciences, National Institutes of Health (2-TI-GM-724).

³ Research career awardee, Institute of General Medical Sciences, National Institutes of Health (5-K6-GM-16284).

¹ Presented in part by Patric L. Friend to the Graduate School of Northwestern University in partial fulfillment of the requirements for the Ph.D. degree.