Disc Diffusion

The results summarized in Table 10.3 give the average zone of inhibition (mm), using standard discs of PERA, PERA/nano ZnO-1, PERA/nano ZnO-3, PERA/nano ZnO-5 and PERA/nano ZnO-7 (5 mg/ml) and fluconazole (100 pg/ml). All of the Candida isolates used in this study showed high degree of sensitivity as is evident from the zone of clearance in each case. Average zone of inhibition is greater (12.65 mm) for 

Fluconazole (lOOfig/ml) showed an average inhibitory zone (mm) of 15.3,16 and 16.5 for invasive, cutaneous and respiratory isolates, n is number of isolates. Each isolate was tested in duplicate. 

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Detecting evolutionary hot spots of antibiotic resistance in Europe Disc diffusion method Genes encoding dihydrofolate reductases confers resistance to trimethoprim... 

In sensitivity tests based on disc diffusion methods, the clear zone of inhibition around each individual disc was measured in three different directions to obtain the mean value of each set. 

Table 37 Effect of tetracycline (Tc) and promazine (Pr) on bacteria by disc diffusion technique...

Table 40 Synergism between ciprofloxacin (Cf) and flupenthixol (Fp) by disc diffusion test...

Fig. 21 shows data on small molecule (GMS) release. The rate of release was about 50 pg/day, representing about 5 %/day of the total entrapped amount. The amount of released GMS was based on a disc diffusion assay. A control experiment using an entrapped, non-conjugated GMS in reverse chemistry nanoparticles demonstrated a total absence of GMS in particles immediately after their preparation (data not shown). 

Resistant by Kirby-Bauer disc diffusion method to penicillin G (P), Tetracycline (T), Clindamycin (C), Novobiocin (N), Kanamycin (K), Chloroamphenicol (Ch), Erythromycin (E). 

The historical gradient plates, ditch-plate and cup-plate techniques (see Hugo 8c Russell, 1998) have been replaced by more quantitative techniques such as disc diffusion (Fig. 11.4), broth and agar dilution, and E-tests (Fig. 11.5). All employ chemically defined media (e.g. Mueller-Hinton or Iso-Sensitest) at a pH of 7.1—1 A, and in the case of solid media, agar plates of defined thickness. 

The potential interaction between two antimicrobials can be demonstrated using a variety of laboratory procedures, e.g. checkerboard MIC assays where the microorganism is exposed to varying dilutions of each drug alone and in combination, disc diffusion tests (see Fig. 11.4) and kinetic kill curve assays. With the former, results can be plotted in the form of a figure called an isobologram (see Fig. 11.7). 

An antibacterial assay using the disc-diffusion method found that the stems and the roots of H. capitellata showed weak to moderate activities against the tested bacteria, Bacillus subtilis B28, Bacillus subtilis B29, Pseudomonas aeruginosa UI 60690 and methicillin resistant Staphylococcus aureus, (MRSA) while the leaves showed weak activity toward Bacillus subtilis B28, MRSA and P. aeruginosa only. However, the roots of H. dichotoma showed moderate antibacterial properties against all four bacteria. All other extracts did not exhibit any antibacterial properties. Table 10 shows the inhibition zones of the methanolic extracts of some Hedyotis species as measured by the disc-diffusion method. 

Table 10 Inhibition zones (mm) of methanolic extracts of Hedyotis species as measured by the disc-diffusion method.

Also hyperibones A-D (76-79) were screened for antibacterial activity by the disc diffusion test against MSSA and MRSA [8]. Hyperibones A, B and D showed mild activity (zone diameter 9.5, 9.2, 6.0, 9.3 mm, for MRSA and 9.0, 9.1, 6.0, 9.0 mm, for MSSA, respectively tetracycline 34 mm, for MRSA and MSSA quercetin 8 mm, for MRSA and MSSA)... 

Antibacterial efficacy decreased after non-ionic and anionic lanndering of the fabric. In particular, the antibacterial activity of Ppy(Cl) samples was severely degraded by anionic laundering. The antibacterial activity of Ppy has been investigated against Streptococcus pneumoniae (RCMB 010010), Enterococcus faecalis (RCMB 010068) and Staphylococcus aureus (RCMB 010028), i.e.. Gram-positive bacteria. The agar disc diffusion method was used to determine the antibacterial activity and ampicillin... 

Media for the Disc Diffusion Test Miieller-Hinton Agar Medium... 

Sterile graduated pipettes of 10, 5, 2 and 1 ml, sterile capped 7.5 x 1.3 cm tubes/ small screw-capped bottles, Pasteur pipettes, an overnight broth culture of the test and control organisms (same as for disc diffusion tests), the required antibiotic in powder form, the required solvent for the antibiotic, sterile distilled water - 500 ml and suitable nutrient broth medium. A suitable rack to hold 22 tubes in two rows, i.e., 11 tubes in each row. 

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