Bactericidal activity, tests

Presence of interfering substances 4.2 Tests for 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. 

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 ... 

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...

An increased susceptibility to Streptococcus zooepidemicus aerosol was not observed in mice exposed to 5 ppm phenol for 3 hours, or for 5 daily 3-hour periods (Aranyi et al. 1986). Neither did the phenol exposures affect pulmonary bactericidal activity towards Klebsiella pneumonia. Although tests for vulnerability to infectious agents do not represent a comprehensive evaluation of immunological competence, the 5-ppm level can be considered a NOAEL for this specific immunological effect, and is recorded in Table 2-1 and plotted in Figure 2-1. 

FIGURE 103-7. Killing curve depicting the effect of concentration on antibiotic bactericidal activity. CPU = colony-forming units MIC = minimal Inhibitory concentration. 0.25-64 times the MIC the organism tested was P. aeruginosa ATCC 27853. (From ref 51.)... 

An aliquot of free iodine extract from Table 3 was tested for bactericidal activity. A = water-soluble formulation, B = partially water-soluble formulation and C = experimental water-insoluble formulation. 

In most cases, viral contamination is picked up by the palm surface of the hand therefore, the use of the whole hand may be quite relevant to testing the bactericidal activity of surgical scrubs and products for preoperative skin antisepsis [76], but not for dealing with viruses. 

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