coryne & rhodoco pt. 2

Pus of exudates

Collected from suppurative conditions

Mid-stream urine

For isolation of C. renale group

Tracheal wash technique (with infusion of saline)

Used for recovey of R. equi from affect3d foals

Corynebacteria

• gram-positive rods with varying degrees of pleomorphism

• Stained smears from animal tissue revela group of cells in parallel (palisades) or cells at a sharp angel to each other (chinese characters)

• Many have metachromatic granules (high-phosphate stores)

R. equi

• usually coccal, but can be rod-shaped (particularly in animal tissue)

• Can be MZN-positive (weakly acid fast)

MacConkey agar

Ox or sheep blood agar

• ______ for detection of gram-negative contaminants

35C for 24-48 hrs

Ox or sheep blood agar

• incubate aerobically at

Modified NANAT R. equie-selective agar medium

• used to recover R. equie from fecal samples

• -

C. pseudotuberculosis

• Produces small, white, dry colonies

• Can be surrounded by a narrow zone of hemolysis after 48- 72hrs of incubation

• After several days, colonies can reach 3mm diameter and appear dry, crumbly and cream in color

C. ulcerans

• produces slightly hemolytic, small, whitish colonies

C. kutscheri

• Produces small, whitish colonies that bear resemblance to those of C. pseudotuberculosis

• Occasional strains are hemolytic.

C. bovis

• Produces small, white, dry and non-hemolytic colonies

• Lipophilic bacterium

  • Has a tendency to appear in the wells of plates inoculated with a milk sample

C. renale

• Non-hemolytic and very small after 24hrs of incubation

• It becomes opaque and dull yellow color as they age

C. pilosum

• Colonies resemble C. renale

• Become cream to yellow color with time

C. cystitidis

• Colonies are similar to C. renale and C. pilosum, but are Transparent to white

R. equi

• Produces small, smooth, shiny and non-hemolytic colonies after 24hrs incubation

• Colonies become larger, mucoid and salmon-pink in color with age (after 48hrs)

• c. pseudotuberculosis

• R. equi

• C. renale

CAMP TEST can be used as quick presumptive tests for ______ interacting with the beta-hemolysin of S. aureus

C. pseudotuberculosis

Inhibits the action of the staphyolococcal beta- hemolysin (reverse CAMP Test)

R. equi and C. renale

• Enhance the action of the staphylococcal beta-hemolysin.

• There is also a synergistic hemolytic effect seen between R. equi and C. pseudotuberculosis on sheep blood aga

• colonial pigmentation

• Presence or absences of growth at ph 5.4

• Biochem ial reactions

Differentiation of members of the C. renale group is based on:

• Molecular genetic-based identification systems

• Chromatographic technique

• Many commercial biochemical systems are available

• However, clinically significant coryneforms that are difficult to identify should be confirmed with:

• hemolysis inhibition

• Indirect hemagglutination

• Anti-hemolysin inhibition

• Complement fixation tests

• Immunodiffusion

• Enzyme-linked immunosorbent assays (ELISA)

Serodoagnostic tests for the detection of antibodies in C. pseudotuberculosis

MHA supplemented with 5% sheep blood

Antimicrobial Susceptibility Test - Coryneform bacteria

• disk diffusion test can be performed using

35C for 24 phrs (48hrs may be required)

Antimicrobial Susceptibility Test - Coryneform bacteria

• incubate at

• The recommended interpretation guidelines for streptococci should be used

MHA (M31-A3, CLSI 2008)

Antimicrobial Susceptibility Test - R. equi

• use disk diffusion test on

• MHA with 5% sheep blood using E-test

• Agar dilution method

• Broth microdilution technique

Minimum Inhibitory Concentration (MIC) - Coryneform bacteria

• determination of MICS can be done on

• agar dilution method

• Broth microdilution technique

• E-test on MHA

Minimum Inhibitory Concentration (MIC) - R. equi

• determination of MICS can be done on

Penicillin

Antimicrobial Resistance - C. pseudotuberculosis

• antibiotic of choice

• however, because there is poor penetration into abscesses, antimicrobial therapy is not recommended for this type of infection.

Combination of ERYTHROMYCIN and RIFAMPIN

Antimicrobial Resistance - R. equi

• antibiotics of choice

• azithromycin

• Clarithromycin

Antimicrobial Resistance - R. equi

• altrnatives to erythromycin

Clarithromycin

has been reported to be more active than azithromycin

• rifampin

• Tetracyclin

• Penicillin G

R equi has been reported to be resistant to