Bactericidal activities

Uses. Diketene is described as having bactericidal activity (136,137). It also raises the octane rating of gasoline (138) but is not used for these purposes in the Western world. 

Number and type of organism Bacteriostatic activity, ppm Bactericidal activity, log reduction... 

Thermal cyclization of the arylaminomethylenemalonate afforded quinoline 3-carboxylate 630 whose reaction with 1,1-dibromoethane gave oxazolo[5,4,3-(/]quinoline 631. Acid hydrolysis and reaction with N-methylpiperazine gave 632 whose bactericidal activity is superior to that of pipemidic acid (82JAPK57203085) (Scheme 108). 

Condensation of 165 with chloroacetamide derivatives afforded (89JIC246) carbamoylhydrazino derivatives 168. Some are active against S. aureus and Escherichia coli. Condensation of 165 with ethyl cyanoace-tate, malononitrile, ethyl acetoacetate, or acetylacetone gave (87AP1191, 87PHA664 89JHC769) 169 and 170, whose bactericidal activity has been reported. 

Most aiititubercular drag s are bacteriostatic (slow or retard the growth of bacteria) against the M. tuberculosis bacillus. These dm usually act to inhibit bacterial cell wall synthesis, which slows the multiplication rate of the bacteria. Only isoniazid is bactericidal, with rifampin and streptomycin having some bactericidal activity. 

Rifampicin possesses significant bactericidal activity at very low eoncentrations against staphylococci. Unfortunately, resistant mutants m arise very rapidly, both in vitro and in vivo. It has thus been reeommended that rifampicin should be eombined with another antibiotie, e.g. vaneomyein, in the treatment of staphylococeal infections. 

Isopropyl alcohol (isopropanol, CH3CHOH.CH3) has slightly greater bactericidal activity than that of ethanol but is also about twice as toxic. It is less active against viruses, particularly non-enveloped viruses, and should be considered a limited-spectrum virucide. Used at concentrations of 60-70%, it is an acceptable alternative to ethanol for preoperative skin treatment and is also employed as a preservative for cosmetics. 

Boiling point increases Bactericidal activity increases Inactivation by organic matter increases Water solubility decreases Tissue toxicity decreases... 

Presence of interfering substances 4.2 Tests for bactericidal activity... 

The effect of temperature on bactericidal activity may be expressed quantitatively by means of a temperature coefficient, either the temperature coefficient per degree rise in temperature, denoted by 6, or the coefficient per 10° rise, the value. 

There is no doubt that the maximum information concerning the fate of a baeterial populahon is obtained by performing viable counts at selected hme intervals. Alternatively, the number of survivors expressed as the percentage remaining viable at the end of a given period of time may be determined by viable counts and this parameter is often used in assessing bactericidal activity. 

Fungal spores or mycelium may be added to the solution under test. At selected time intervals, samples can be subcultured into suitable media and the presence or absence of growth noted after incubation. A quantitative assessment similar to that described for bactericidal activity (section 3.2, Table 11.3) can also be undertaken. 

Russell A.D. (1981) Neutralization procedures in the evaluation of bactericidal activity. In Disinfectants Their Use and Evaluation of Effectiveness (eds C.H. Collins, M.C. Allwood, S.F. Bloomfield A. Fox), pp. 45-59. London Academic Press. 

While it may be desirable to limit the excess, chronic and inappropriate generation of phagocyte-derived ROMs, it is necessary to achieve this without simultaneously compromising their vital bactericidal function. The orally effective iron chelator 2,3-dihydroxybenzoate has been shown to decrease PMN ROM generation without a corresponding loss of bactericidal activity to phagocytosed Staphylococctis aureus (Boxer et al., 1978). 

The coefficients of the regression are all highly significant (p < 0.0001) and the fit of the model to the observed data is shown in Fig. 37.1. Using non-linear regression we obtain the bilinear Hansch model for the bactericidal activities of the 17 phenol analogs (Table 37.2) ... 

Fig. 37.1. Quadratic Hansch model fitted to the bactericidal activities (log 1/C) of 10 doubly substituted phenols in Table 37.2 as a function of lipophilicity (log P) [20].

Mode of action Interferes with bacterial cell wall synthesis during active multiplication, causing cell wall death and resultant bactericidal activity Inhibits bacterial cell wall synthesis by binding to one or more of the penicillin-binding proteins, which in turn inhibit the final transpeptidation step of peptidoglycan synthesis in bacterial cell walls bacteria usually lyse from ongoing autolytic enzyme activity... 

The first draft (finished in 1993 and revised in 1995) describes a test method for determination of the bactericidal activity of a chemical disinfectant applied to a contaminated surface under laboratory conditions ... 

There are not yet many products on the market that show bactericidal activity and meet at the same time the requirements for application in plastics ... 

Test Method. Due to the fact that there does not yet exist an official method for the investigation of the bactericidal activity of surfaces an adequate method had to be developed ... 

Table 3 Scoring System of the Test on Bactericidal Activity...

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