THE RESISTANCE OF BACTERIAL SPORES WITH REFERENCE TO SPORE GERMINATION AND ITS INHIBITION

Abstract

The resistance of bacterial spores has not been reviewed previously in this publication. There are many important phases of spore resistance which might be reviewed and discussed. Considering all the chemical and physical influences which have been tested in some way upon the resistance and via­ bility of bacterial spores, the literature is immense, overwhelming, and ex­ ceedingly contradictory. Any pretense to a thorough and comprehensive coverage would be presumptuous if not futile. Therefore, for the purposes of this review, consideration has been limited to what the writer considers some of the significant information with reference to the resistance of bacterial spores in relation to spore germination and its inhibition. Even with this limitation, it is impossible to cover all the relevant literature upon the sub­ ject. Before proceeding to the specific subject matter of this review, a few gen­ eral references upon the resistance of bacterial spores may be mentioned. Knaysi (1) presents an excellent and comprehensive review and evaluation of the literature upon the bacterial endospore which includes discussions of spore resistance and germination. Heat resistance has been reviewed and discussed by Esty (2), Rahn (3), and Schmidt (4). Radiation resistance has been reviewed by Lea (5) and Proctor & Goldblith (6, 7, 8). Chemical re­ sistance has been treated extensively by Rahn (9). Many of the individual chapters in Reddish (10) contain data and considerations bearing upon spore destruction by chemicals together with extensive references to the literature. In view of the wide variety of chemical agents active to some de­ gree in a lethal manner upon spores, it is evident that this subject does not lend itself to attempts at systematic review such as are possible with heat and radiation. The various papers appearing in the Symposium on the Biology of Bacterial Spores (11) also present very good reference material upon the various aspects of spore resistance. Unfortunately perhaps for microbiologists, death of a microorganism has been defined in terms of the inability to reproduce to the point of macro­ scopic detection, that is the production of a colony, grossly visible growth, or a detectable metabolic product. Therefore all studies of the resistance of bacterial spores are based upon the determination of the presence of sur­ vivors following some specified treatment. This determination may be quali-