Blood agar plates

Duplicate counts are made using serial dilutions up to 10-6 and drop plates. Solutions are then spotted onto blood agar plates and incubated at 37 °C for 18 hours after which the number of colony forming units is determined. To pass the BA Challenge Test there must be no growth from the aliquots taken at 15 minutes or more from the 1 400 and 1 1600 dilutions. 

Inoculate a fresh colony from a blood agar plate into THY medium. 

Apply 100 pi of each dilution to a blood agar plate and gently swirl the plate. 

Take the medium from step d of the subculture procedure and centrifuge at 800 g for 15 min. Discard the supernatant. Using a platinum loop, place the sediment on a blood agar plate (Appendix 4) and incubate at 37°C for at least 2 days to check for bacterial growth (Chapter 9). 

Also streak samples onto two blood agar plates (Appendix 4) and two deoxycholate plates. 

The bacterium is grown on blood agar plates and stored in a mixture of Mueller-Hinton broth containing 20% (v/v) glycerol. In this mixture, bacteria can be stored in small aliquots for several years at -70°C. 

To prepare plate cultures, frozen stocks are placed on dry ice and are stabbed with a hot wire loop. Material adhering to the loop is then plated onto the blood agar plates. Frozen stocks may require several passages to regain growth characteristics. 

To prepare a seeding culture, fill a 25 pL universal with approximately 10 pL of sterile Mueller-Hinton broth and seed these with 1-2 colonies from the blood agar plate. This is then incubated at 37°C overnight with vigorous shaking at approximately 200 rpm. 

Before using heparin with antibiotics, blood agar plates with various organisms were cultured. The plates were prepared in the ordinary fashion. In a second set of cultures, disks with antibiotics were soaked in heparin, and finally heparin was incorporated into the blood agar alone. Examination of the plates made it obvious that heparin did not inhibit the action of the antibiotics and often seemed to enhance it. It is not known whether heparin is truly an antibiotic. 

The significant advantages of direct plasma treatment (Fridman et al., 2007) have been demonstrated by comparison of two types of experiments with DBD discharges. In one set of experiments, a surface covered by bacteria was employed as one DBD electrode a second smaller-area DBD electrode was placed over it. Areas of sterilization with and without air flow parallel to the surface have been compared. In another set of experiments, a surface covered by bacteria was employed as one DBD electrode the rate of sterilization in the system was compared to the case when the surface was separated from the DBD by a grounded mesh electrode (see Fig. 12-8). Bacterial samples for the experiments were collected from de-identified skin samples from human cadavers. Bacteria from the skin samples consisted of staphylococci, streptococci, and Candida species of yeast. They were transferred onto the blood agar plate, cultured, and diluted in lOX PBS to approximately 10 cfu/mL. To quantily sterilization efficiency, 20 drops of 10 cfu/mL bacteria were placed on the agar surface, left to dry for 5 min, and finally treated by plasma. This volume... 

Blood agar plates Adjust trypticase soy agar base to pH 6.0 and then autoclave. Cool sterilized agar in a 50 °C water bath. Add defibrinated sheep blood to 5% final concentration immediately prior to pouring plates. Store at 4 °C. 

Titer dilute GAS-PBS solutions to confirm that correct infectious dose was given to the animals for each of the two GAS strains. Use THY agar or TSA blood agar plates for plating serial dilutions for titer determination. 

The bactericidal test in this, and the following tables, is based on that of Miles and Misra (1938). At the end of the given time, samples were withdrawn, diluted, and inoculated on a dried blood—agar plate. The plates were read after 48 hours at 37°C. Symbols — no growth +, up to 50 colonies + +, 50—150 colonies + ++, uncountable. (Albert, Gibson and Rubbo, 1953.)... 

Preparation of culture supernatants - R haemolytica biotype A1 was grown as previously described (17). Briefly, colonies from a blood agar plate wCTe used to inoculate tryptic soy broth. This culture was incubated at 37 C for 4.5 hours. This broth was used to inoculate fresh tryptic soy broth which was incubated for 1 hour at 370 C with 5% CO2 bubbled throu it. The broth was stirred as rapidly as possible without foaming. After 1 hour of incubation bacteria were removed from the culture by ultrafiltration (Pellicon, Millipore, Inc.). Culture supernatants free of bacteria were lyophilized and stored dessicated at -20 C until loaded into hydrogels. 

The anti bacterial characteristics of the fiibrics made fiom 100% bamboo fibre and bamboo fibre/cotton blends as evaluated by parallel streak method and die qualitative and quantitative assessment of bacterial growth in die 100% bamboo fibre material (nevdy developed) and the in cotton material (regularly used 1 the hospital) vdiich were exposed to surgical conditions by blood agar plate method and the assessment by Turbidity method are given as below. 

The bacterial growth in the blood agar plates for 100% bamboo fibre material (newly developed) as well as 100% cotton material (regularly used by the hospital) is depicted in the form of photographs in Figs. 6 7. 

From Fig.6 it could be seen that the blood plate with bamboo fibre material exhibits less bacterial colonies when compared to the blood agar plate with cotton material. It is to be noted that both the materials were esqxised to toe same surgical conditions. 

From the results of the blood agar plate method, it is very clear that the material made of bamboo fibres is able to inhibit the growth of pathogenic bacteria effectively. 

FIGURE 1 The 5% sheep blood agar plates with colonies of S. aureus ATCC 25923 standard strain from bacterial suspensions after incubation with tested materials (PSU and PSU/Ag composites) and controls. 

Keppel, A. D. and Janovy, J., JR. 1980. Morphology of LeishmanU donovani colonies grown on blood agar plates. J. Parasitol. 66(5) 849-851. 

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