Mastitis Mastitis is the inflammation of mammary gland characterized by edema, hemorrhage and fibrosis of udder. Mastitis is always infectious and is a disease of lactating glands. Infections enter through teat canal to cause mastitis. It occurs when white blood cells (leukocytes) are released into the mammary gland , usually in response to bacteria invading the teat canal. Milk -secreting tissue and various ducts throughout the mammary gland are damaged due to toxins released by the bacteria. Mastitis can also occur as a result of chemical , mechanical, or thermal injury . Types : 1 - Contagious : pathogens that cause mastitis tend to live on the cow's udder and teat skin and transfer from affected cow (or quarter) to unaffected cow (or quarter) during milking. They adhere easily to the skin, colonizing the teat end and then 'grow' into the teat canal, where infection occurs . 2 - Environmental : Present in the housing and bedding - can transfer during milking or between milking, when the cow is loafing, eating or lying down. The pathogen can enter the teat canal by force during milking, for example, when liner slippage occurs. These environmental pathogens do not generally possess the same ability as contagious pathogens to adhere to and colonize the teat . Common bacteria causing mastitis :
Transcript
Mastitis
Mastitis is the inflammation of mammary gland characterized by edema, hemorrhage and fibrosis of udder. Mastitis is always infectious and is a disease of lactating glands. Infections enter through teat canal to cause mastitis. It occurs when white blood cells (leukocytes) are released into the mammary gland, usually in response to bacteria invading the teat canal. Milk-secreting tissue and various ducts throughout the mammary gland are damaged due to toxins released by the bacteria. Mastitis can also occur as a result of chemical, mechanical, or thermal injury.
Types:
1 - Contagious :
pathogens that cause mastitis tend to live on the cow's udder and teat skin and transfer from affected cow (or quarter) to unaffected cow (or quarter) during milking. They adhere easily to the skin, colonizing the teat end and then 'grow'
into the teat canal, where infection occurs .
2 - Environmental :
Present in the housing and bedding - can transfer during milking or between milking, when the cow is loafing, eating or lying down. The pathogen can enter the teat canal by force during milking, for example, when liner slippage occurs. These environmental pathogens do not generally possess the same ability as contagious pathogens to adhere to and colonize the teat.
Lab diagnosisStreptococcus agalactiae (also known as Group B streptococcus or GBS) is a gram-positive streptococcus.
Colonial morphology of S. agalactiae in culture is typically gray to whitish-gray in color when grown on sheep blood agar colonies surrounded by a narrow zone of β-hemolysis.
GBS is characterized by the presence in the cell wall of the antigen group B of Lancefield classification (Lancefield grouping) that can be detected directly in intact bacteria using latex agglutination tests.
The CAMP test is also another important test for identification of GBS. The CAMP factor produced by GBS acts synergistically with the staphylococcal β-hemolysin inducing enhanced hemolysis of sheep or bovine erythrocytes.
GBS is also able to hydrolyze hippurate and this test can also be used to identify presumptively GBS.
Streptococcus agalactiae stains violet with gram stain
Streptococcus agalactiae on CAP blood agar plate.
Positive CAMP test indicated by the formation of an arrowhead where Streptococcus agalactiae meets the Staphylococcus aureus (white middle streak)
Streptococcus agalactiae, latex agglutination.
Purple color indicates for presence of S. agalactiae
Depending upon the type of infection present, an appropriate specimen is obtained accordingly and sent to the laboratory for definitive identification by using biochemical or enzyme-based tests .
A gram stain is first performed to guide the way, which should show typical gram-positive bacteria, cocci, in clusters.
S. aureus grows readily on blood agar forming beta-hemolysis.
Second, the isolate is cultured on mannitol salt agar, which is a selective medium with 7–9% NaCl that allows S. aureus to grow, producing yellow-colored colonies as a result of mannitol fermentation and subsequent drop in the medium's pH. Furthermore, for differentiation on the species level.
catalase (positive for all Staphylococcus species),
coagulase (fibrin clot formation, positive for S. aureus)
Typical gram-positive cocci, in clusters (Gram stain)
S. aureus appears as grape-like clusters when viewed through a microscope, and has large, round, golden-yellow colonies, often with beta hemolysis, when grown on blood agar plates. Beta hemolysis .
Fibrin clot formation as positive result for Staph aureus.
Yellow, mannitol positive Staphylococcus aureus with yellowish halo around colonies. Whittish, mannitol negative colonies of S. epidermidis.
Baird Parker Agar is a selective medium for the isolation and presumptive identification of coagulase-positive Staphylococci produce dark gray to black colonies due to tellurite reduction; staphylococci that produce lecithinase break down the egg yolk and cause clear zones around respective colonies. An opaque zone of precipitation may form due to lipase activity
An appropriate sample is taken and sent to the lab. At first gram stain is preformed which shows a red-rod shaped bacteria under microscope.E. coli grows readily on MaCconckey media.Then catalase test is preformed “positive”Then oxidase “negative”
Gram negative rod shaped bacteria under light microscope
Typical E.coli: rod-shaped bacteria (bacilli) with rounded ends, sometimes forming filaments with electron microscope
Escherichia coli concave colonies on MacConkey agar.
Since E.coli doesn’t have oxidase enzyme so there will be no change as a negative result.
Effervescence of gases as a positive result for presence of E. coli that contains catalase enzyme which split H2O2
Gram stain is preformed which shows gram negative rod bacteria.Then catalase test is done which shows effervescence of gases that indicates presence of Klebsiella spp Urease test is preformed after that shows red color as a positive result.
Lab diagnosis :Pseudomonas aeruginosa is often preliminarily identified by its typical odor in vitro. The smell is
described as grape-like, tortilla-like.Gram stain is preformed that shows gram-negative rod bacteria.Then citrate,catalase and oxidase tests are preformed both of them give positive result for pseudomonas spp.
