Gram Negative Bacteria PDF

## Reorganized Gram Negatives ### Pseudomonas aeruginosa - Main pathogen in humans - Common in moist area of hospitals - Obligate aerobe - Sweet grape like odor - Oxidase positive - Does not ferment glucose, lactose - Grows at 42 degrees Celsius **Gram Negatives: The Pseudomonas** - Motile - Aerob...

## Reorganized Gram Negatives ### Pseudomonas aeruginosa - Main pathogen in humans - Common in moist area of hospitals - Obligate aerobe - Sweet grape like odor - Oxidase positive - Does not ferment glucose, lactose - Grows at 42 degrees Celsius **Gram Negatives: The Pseudomonas** - Motile - Aerobic - Occur in water, plants and animals **Infections of Aerugonosa** - Skin infection - Eye infection - Ear infection **Serious pathogens associate with aerugionsoa** 1. Veniliated associated pneumonia (VAP) 2. Nosocomil pneumonia 3. UTI **At risk population:** - Neutropenic patients - Burn patients - CF - Mechanincal ventilator **Virulent factors for aerugonosa:** - Exotoxin A - Pili - Lipopolysaccharide - Chronic colonization **Mechanism of resistance for psuedomnas aergunosa** - Beta lactamase - Ability to form biofilm - Multi drug efflux pumps ### Stenotrophomas Maltophilia - Lavender green or gray color - Oxidase negative - Oxidizes gluecose and maltose - Does not ferment lactose - Hospital acquired infection - Bactrim is the drug of choice ### Burkholderia - Cause of glanders - Can be zoonotic in humans ### Acinetobacter - Aerobic - Non-gluecose - Non-lactose fermenter - Short rods on gram stain - Widely distributed in soil or water - Significant nosocomial pathogen - Penumonias, bacterimias, wound infection - Highly resistant - May need to go to colistin ### The HACEK Bacteria - Eikenella corrodens – small fastidious gram neg rod - Part of gingival and bowel flora - Oxidase positive ### Moraxella species - Coccobacillus - Associated with bronchitis and pneumonia ### Neisseria Species ### Pasturella multocida - Primarily animal pathogen but can be zoonotic - Can get Cellulitis via animal bites - Non motile gram negative coccobacilli - Should always be suspected in skin infections due to cats and dogs - Treatment is augementin ### Yersinia species - Infection of wild rodents transmitted to humans and other mammals - Called the black death - Can be used as a biological weapon ### Y. Enterocolitis and pseudotuberculosis - Can cause diarrheal disease in humans - Non lactose fermenting ### Haemophilus Influenzae type B - Antiphagocytic capsule - Antigen B is the worst for humans - Polyribose phosphate of H influenzae is its major virulence factor - Non invasive infection: - Otitis media - Sinusitis - Pharyngitis - Invasive: - Pneumonia, septic arithritis, osteomyletis - Vaccine ### Bacteroides Fragilis - Part of normal intestinal flora - Can be pathogenic generally syngergistically with other bacteria - Polymicrobic infection - Capsular polysaccharide is a virulent factor - Faculative anaerobe - Hallmark infections are aspiration pneumonia and intra abdominal abcess - Can be treated with metronidazole or clindamycin ### Haemophilus - Small pleomorphic bacteria - Require enriched chocolate agar (contain no chocolate) - Contain X(Heme) and V (Nicotinamide-adeninediculceotide) factors - Can be in normal respitory flora - Cause wide array of disease