Equine Reproductive Procedures. Группа авторов. Читать онлайн. Newlib. NEWLIB.NET

Автор: Группа авторов
Издательство: John Wiley & Sons Limited
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Жанр произведения: Биология
Год издания: 0
isbn: 9781119555933
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all four quadrants with the sample swab on the inside of each corner of the plate (primary streak) (see Figure 14.1 as an example).Figure 14.1 Inoculation of a streak plate for cultivation of microbial organisms. This example shows how to streak one entire plate; a slight modification is required to streak each quadrant of a quad plate.

       With a new sterile swab, streak through the primary streak one or more times and continue to streak the second third of the plate (secondary streak).

       With a new sterile swab, streak through the secondary streak one or more times and continue to streak the final third of the plate (tertiary streak). The concept is to separate the colonies so that individual colonies can be identified.

       Perform the same streaking pattern on the other quadrants.Figure 14.2 Culture of Streptococcus equi subspecies zooepidemicus on a quad plate with TSA with 5% sheep blood (upper right), MacConkey II agar (upper left), Gram‐positive chromogenic agar (lower right), and Gram‐negative chromogenic agar (lower left). Note the growth of small white colonies with β‐hemolysis (black arrow) on blood agar, the lack of growth on MacConkey agar, and the small light blue colonies on the Gram‐positive chromogenic agar.

       If additional agars are to be used, inoculate in the same manner as previously described.

       Incubate the plate(s), bottom side up in a 37°C (99°F) incubator for 20–24 hours.

       After incubation, observe the quad plate for the appearance of any colony growth and determine if more than one type of colony is present. Identify hemolytic activity of colonies developing on TSA agar. Determine if contaminants are present (e.g., where are the colonies located on the plate, are they actually touching a streak line, are there more than one type of colony?) (Figures ; Table 14.2).

       Observe any additional inoculated agars for presumptive identification or growth of a fungal/yeast organism (i.e., Sabouraud agar).

       Characterize the amount of growth as either no growth, very light growth, light growth, moderate growth, or heavy growth.

       Plates with mixed growth should be subcultured and individual organisms subsequently identified.

       Plates should be cultured for a minimum of 72 hours before being discarded.

Photo depicts culture of Escherichia coli on a quad plate with TSA with 5% sheep blood (upper right), MacConkey II agar (upper left), Gram-positive chromogenic agar (lower right), and Gram-negative chromogenic agar (lower left). Note the growth of cream-colored colonies without hemolysis on blood agar, the medium-sized pink colonies on MacConkey agar, and the pink to red colonies on Gram-negative chromogenic agar. Photo depicts culture of Pseudomonas aeruginosa on a quad plate with TSA with 5% sheep blood (upper right), MacConkey II agar (upper left), Gram-positive chromogenic agar (lower right), and Gram-negative chromogenic agar (lower left). Note the growth of flat metallic - colonies on blood agar, the large pale ish colonies on MacConkey agar, and the growth of transparent white to colonies on Gram-negative chromogenic agar. Photo depicts culture of Klebsiella pneumoniae on a quad plate with TSA with 5% sheep blood (upper right), MacConkey II agar (upper left), Gram-positive chromogenic agar (lower right), and Gram-negative chromogenic agar (lower left). Note the growth of large mucoid colonies without hemolysis on blood agar, the large pink mucoid colonies on MacConkey agar, and the growth of large colonies with a slight pink halo on Gram-negative chromogenic agar.
Organism Gram Stain Morphology TSA/5% Sheep Blood Agar MacConkey Agar Chromogenic Agar Comments
Streptococcus equi subsp. zooepidemicus Pos. Cocci (ovoid, chains) Small, white, round colonies (β‐hemolysis) (0.5–1.0 mm) No growth Small, light blue colonies
Escherichia coli Neg. Rods Cream‐colored colonies (α‐hemolysis) (2–3 mm) Medium sized, gray to pink colonies Medium, pink to red colonies
Klebsiella pneumoniae Neg. Rods Large, gray, mucoid colonies (non‐hemolytic) (2–4 mm) Large, pink, mucoid colonies Large, blue with slight pink halo colonies
Pseudomonas aeruginosa Neg. Rods Flat metallic blue colonies (β‐hemolysis) (3–4 mm) Large, pale greenish colonies Transparent white to green colonies Grape‐like odor on blood agar; fluorescence with Wood’s UV light
Staphylococcus aureus Pos. Cocci (round, clusters) Medium, cream to gold colonies (± βhemolysis) (2–3 mm) No growth or limited growth of pink colonies White to light yellow colonies

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