NEW non fermenter gram -ve part 1

Non-fermenting Gram-negative bacteria are

Gram-negative aerobic rods that do not ferment carbohydrates

Examples of non-fermenting Gram-negative bacteria

Pseudomonas Burkholderia Acinetobacter Bordetella

Most clinically important non-fermenter in veterinary medicine

Pseudomonas aeruginosa

Non-fermenting Gram-negative bacteria are commonly found in

Soil water plants and hospital environments

Non-fermenters are commonly associated with

Opportunistic infections

Why are non-fermenters difficult to treat?

They are intrinsically resistant to many antibiotics

Pseudomonas aeruginosa Gram stain

Gram-negative rod

Arrangement of Pseudomonas aeruginosa

Single or pairs

Oxygen requirement of Pseudomonas aeruginosa

Obligate aerobe

Carbohydrate metabolism of Pseudomonas aeruginosa

Non-fermenter

Oxidase test of Pseudomonas aeruginosa

Positive

Catalase test of Pseudomonas aeruginosa

Positive

Natural habitat of Pseudomonas aeruginosa

Soil water skin and mucous membranes

Characteristic odor of Pseudomonas aeruginosa

Fruity or grape-like odor

Characteristic colony appearance of Pseudomonas aeruginosa

Large 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 that damage host tissues

Yellow-green fluorescent pigment produced by Pseudomonas aeruginosa

Pyoverdin

Function of pyoverdin

Siderophore for iron acquisition

Dark red pigment produced by Pseudomonas aeruginosa

Pyorubin

Brown-black pigment produced by Pseudomonas aeruginosa

Pyomelanin

Major virulence factors of Pseudomonas aeruginosa

Capsule fimbriae pyocyanin pyoverdin exotoxin A elastase hemolysin leukocidin and biofilm formation

Function of capsule

Prevents phagocytosis

Function of fimbriae

Attachment to host tissues

Function of exotoxin A

Inhibits protein synthesis causing cell death

Function of elastase

Destroys elastin and damages blood vessels and lung tissue

Function of hemolysin

Lyses red blood cells

Function of leukocidin

Kills leukocytes

Importance of biofilm formation

Protects bacteria from antibiotics and host defenses

Pseudomonas aeruginosa is primarily

An opportunistic pathogen

Animals most susceptible to Pseudomonas infection

Immunocompromised animals

Predisposing factors for Pseudomonas infection

Burns wounds surgery prolonged antibiotic therapy and immunosuppression

Pseudomonas aeruginosa commonly causes

Otitis externa

Pseudomonas aeruginosa commonly causes

Urinary tract infections

Pseudomonas aeruginosa commonly causes

Wound infections

Pseudomonas aeruginosa commonly causes

Pneumonia

Pseudomonas aeruginosa commonly causes

Mastitis

Pseudomonas aeruginosa commonly causes in horses

Ulcerative keratitis

Pseudomonas aeruginosa commonly causes in sheep

Fleece rot

Characteristic appearance of fleece rot

Green discoloration of wool

Characteristic color of Pseudomonas wound infections

Blue-green

Food spoilage caused by Pseudomonas

Meat milk eggs and refrigerated foods

Why can Pseudomonas spoil refrigerated foods?

It grows at low temperatures

Why is Pseudomonas aeruginosa difficult to treat?

Intrinsic and acquired antimicrobial resistance

Mechanism of antibiotic resistance in Pseudomonas

Low membrane permeability efflux pumps enzyme production and biofilm formation

Acinetobacter are

Gram-negative non-fermenting coccobacilli

Habitat of Acinetobacter

Soil water and hospital environments

Acinetobacter infections commonly involve

Wounds pneumonia septicemia and urinary tract infections

Why is Acinetobacter clinically important?

Multidrug resistance

Best clues for Pseudomonas aeruginosa

Oxidase positive obligate aerobe blue-green pigment fruity odor non-fermenter and opportunistic pathogen

Best clues for Acinetobacter

Non-fermenting Gram-negative coccobacillus with multidrug resistance