entero part 3

What are the methods of diagnosis for E. coli infections?

Clinical signs and pathology, specimen collection, isolation, identification, serotyping, lab techniques for enterotoxins.

What specimens are collected in enteric diseases for diagnosing E. coli?

Faecal samples.

What specimens are collected from septicaemic cases for diagnosing E. coli?

Tissue specimens.

What specimen is collected in suspected mastitis for E. coli diagnosis?

Mastitis milk.

What specimen is collected in urinary infections for E. coli diagnosis?

Mid-stream urine.

What specimens are collected from suspected cases of pyometra or metritis for E. coli diagnosis?

Cervical swabs.

What culture media are used to isolate E. coli?

Blood agar, MacConkey agar, and EMB agar.

Where can E. coli be isolated in pure culture in enteric infections?

Small intestine.

From which organs can E. coli be recovered in septicemic conditions?

Liver, spleen, kidneys, and lungs.

What lab cells are used to detect heat labile enterotoxins of E. coli?

Mouse adrenal cells, Chinese hamster ovary cells, and vero monkey kidney cells.

What test involves injecting bacterial culture supernatants into ligated ileal loops of rabbits?

Detection of heat labile enterotoxin.

What indicates a positive test in the ligated ileal loop method?

Accumulation of fluid in the loop.

How is the heat stable enterotoxin (ST) detected?

By injecting culture supernatants into milk-filled stomachs of infant mice.

How long after injection are the infant mice examined for detection of ST enterotoxin?

4 hours.

What is a positive sign for ST detection in mice?

Dilatation of the intestine due to fluid accumulation.

Which methods can confirm the presence of enterotoxins or fimbrial antigens in E. coli?

Immunological methods or PCR.

Which medium is used for expression of fimbrial antigens in E. coli isolates?

Minca medium.

What test is used for serotype identification of E. coli?

Slide agglutination tests for O and H antigens.

What prevents intestinal colonization by pathogenic E. coli in neonates?

Colostral antibodies.

By when does the absorption of gamma globulin from the intestine become negligible?

By 36 hours after birth.

How is passive immunization against E. coli achieved in pigs?

By immunizing sows with E.coli K88 antigen during gestation.

What is the result of sow immunization on piglets?

Anti K-88 antibodies in colostrum prevent K88 adhesion in piglets.

What environmental practice should be avoided in cattle before calving to aid in E. coli prevention?

Moving the mother to a new environment shortly before calving.

How many types of vaccines are available for active immunization against E. coli?

Three.

What are the three types of E. coli vaccines available?

Live E.coli K88 antigen (oral), killed E.coli with K88 (bacterin), bacteria-free K88 antigen (subunit vaccine).

Which vaccine is used to enhance colostral protection in pregnant cows?

Purified E.coli K99 fimbrial or whole cell preparations, often with rotavirus antigen.

What antibiotics are commonly used in the prevention and treatment of colibacillosis?

Oxytetracycline, chlortetracycline, streptomycin, ciprofloxacin, and enrofloxacin.

What is a consequence of antibiotic use in E. coli treatment?

Development of resistant strains of E. coli.