Other Gram -ve NON fermenting part 1

Genus Pseudomonas characteristics

Gram-negative medium-sized rods

Arrangement of Pseudomonas

Pairs

Oxygen requirement of Pseudomonas

Obligate aerobes

Pseudomonas are fermenters or nonfermenters?

Nonfermenters

Oxidase test of Pseudomonas

Positive

Catalase test of Pseudomonas

Positive

Most important species of Pseudomonas

Pseudomonas aeruginosa

Habitat of Pseudomonas aeruginosa

Soil water skin and mucous membranes

Characteristic odor of Pseudomonas aeruginosa colonies

Fruity/grape-like odor

Characteristic colony appearance of Pseudomonas aeruginosa

Mucoid colonies

Serotyping of Pseudomonas aeruginosa is based on

O (somatic) antigens

Blue-green pigment produced by Pseudomonas aeruginosa

Pyocyanin

Function of pyocyanin

Produces reactive oxygen species and damages host tissues

Yellow-green fluorescent pigment produced by Pseudomonas aeruginosa

Pyoverdin

Function of pyoverdin

Siderophore that acquires iron

Dark red pigment produced by Pseudomonas aeruginosa

Pyorubin

Brown-black pigment produced by Pseudomonas aeruginosa

Pyomelanin

Major virulence factors of Pseudomonas aeruginosa

Fimbriae capsule pyocyanin pyoverdin exotoxin A elastase hemolysin leukocidin and drug resistance

Function of fimbriae

Adhesion

Function of capsule

Resists phagocytosis

Most important toxin of Pseudomonas aeruginosa

Exotoxin A

Mechanism of exotoxin A

Inhibits host cell protein synthesis

Result of exotoxin A activity

Cell death

Function of elastase

Destroys elastin causing tissue and lung damage

Function of hemolysin

Lyses red blood cells

Function of leukocidin

Kills leukocytes

Pseudomonas aeruginosa is primarily what type of pathogen?

An opportunistic pathogen

Animals at greatest risk of Pseudomonas infection

Immunocompromised animals

Other major predisposing factors for Pseudomonas infection

Burns and concurrent infections

Pseudomonas aeruginosa commonly causes

Urinary tract infections, ear and wound infections

Pseudomonas aeruginosa commonly causes

Ear infections

Pseudomonas aeruginosa commonly causes

Wound infections

Characteristic color of Pseudomonas wound infections

Blue-green

Pseudomonas aeruginosa commonly causes (2)

Pneumonia and mastitis

Pseudomonas aeruginosa commonly causes

Mastitis

Pseudomonas aeruginosa commonly causes in sheep

Fleece rot (green wool)

Pseudomonas aeruginosa commonly causes in horses

Ulcerative keratitis

Characteristic appearance of fleece rot

Green discoloration of wool

Why is Pseudomonas difficult to treat?

High antimicrobial resistance due to porin-mediated drug resistance

Best clues for identifying Pseudomonas aeruginosa

Oxidase positive obligate aerobe blue-green pigment fruity odor and nonfermenter

Genus Burkholderia characteristics

Gram-negative rods

Oxygen requirement of Burkholderia

Obligate aerobes

Major virulence factor of Burkholderia

Polysaccharide capsule

Burkholderia mallei causes

Glanders

Primary host of Burkholderia mallei

Horses and other equids

Other susceptible hosts of Burkholderia mallei

Humans cats and dogs

Transmission of Burkholderia mallei

Ingestion of contaminated food or water

Other routes of Burkholderia mallei transmission

Inhalation and skin wounds

Burkholderia mallei primarily causes

Chronic disease

Characteristic lesion of glanders

Caseous abscesses

Burkholderia mallei induces

Delayed hypersensitivity

Three forms of glanders

Nasal pulmonary and cutaneous (farcy)

Nasal form of glanders causes

Nodular lesions and ulcers on the nasal septum

Pulmonary form of glanders causes

Nodular lesions and abscesses in the lungs

Cutaneous form of glanders is called

Farcy

Cutaneous glanders is characterized by

Lymphangitis with discharging abscesses along lymphatic vessels

Diagnostic skin test for glanders

Mallein test

Mallein test is based on

Delayed hypersensitivity reaction

Mallein test is performed by

Intrapalpebral injection of mallein

Positive mallein test

Eyelid swelling with purulent ocular discharge

Time to read a mallein test

More than 24 hours after injection

Burkholderia pseudomallei causes

Melioidosis (Pseudoglanders)

PS: because it looks and acts almost exactly like an ancient, highly contagious veterinary disease called glanders, but it is caused by a different, "pseudo" (false) version of the bacteria

Habitat of Burkholderia pseudomallei

Soil water and vegetation

Transmission of Burkholderia pseudomallei

Inhalation ingestion or skin wounds

Acute form of melioidosis causes

Septicemia with abscesses in multiple organs

Chronic melioidosis resembles

Glanders

Lawsonia intracellularis characteristics

Slender curved Gram-negative rod

Oxygen requirement of Lawsonia intracellularis

Microaerophilic (require low levels of oxygen to survive)

Lifestyle of Lawsonia intracellularis

Obligate intracellular bacterium

Lawsonia intracellularis can only be grown in

Cell culture

Lawsonia intracellularis causes

Proliferative enteropathy (contagious GIT disease)

Primary host of Lawsonia intracellularis

Pigs

Most susceptible pigs

Post-weaning and young growing pigs

Lawsonia intracellularis replicates in

Ileal crypt epithelial cells

Effect of Lawsonia intracellularis on crypt cells

Hyperplasia (proliferation) (an abnormal increase in the number of cells in an organ or tissue, which causes it to enlarge)

Most severely affected intestinal region

Terminal ileum

Clinical signs of proliferative enteropathy

Diarrhea dehydration abdominal pain and arched back

Characteristic intestinal lesion

Thickened intestinal mucosa

Proliferative hemorrhagic enteropathy occurs most commonly in

Older pigs

Characteristic lesion of proliferative hemorrhagic enteropathy

Thickened intestinal wall with hemorrhage into the lumen

Case fatality rate of proliferative hemorrhagic enteropathy

Approximately 50%

Porcine intestinal adenomatosis occurs in

Pigs younger than 12 weeks

Lesions of porcine intestinal adenomatosis

Thickened mucosa of terminal ileum and upper large intestine

Clinical signs of porcine intestinal adenomatosis

Anorexia wasting and recovery

Necrotic enteritis caused by Lawsonia intracellularis occurs in

Pigs younger than 12 weeks

Characteristic lesion of necrotic enteritis

Necrosis of proliferative intestinal mucosa

Clinical outcome of necrotic enteritis

Sudden death

Regional ileitis occurs in

Pigs younger than 12 weeks

Nickname for regional ileitis

Hosepipe gut

Why is it called hosepipe gut?

Thick rigid intestine due to muscular hypertrophy

Lesions of regional ileitis

Muscular hypertrophy with inflammation of the submucosa and lamina propria

Serious complication of regional ileitis

Intestinal rupture and peritonitis

Clinical outcome of intestinal rupture

Sudden death

Best clue for Lawsonia intracellularis on an exam

Intracellular curved Gram-negative rod causing proliferative enteropathy with thickened terminal ileum in post-weaning pigs