Bacterial Survey – Gram negatives2) Aerobic bacilli and cocci

•Pseudomonas

•Legionella

•Neisseria

•Rhizobium

•Agrobacterium

•Methanobacterium

Pseudomonas

• Large taxon; K/K on TSI• “garbage disposals” of the

MO world• Ubiquitous; assoc. with

nosocomial infections• Resistance and virulence

factors/traits• Opportunistic; can affect

compromised hosts– Burn patients– Cancer patients– Transplant patients

Legionella

• Recently discovered (1976) at Legionnaire’s convention

• Found in cool waters• Transported by aerosols• Produces mild-severe

respiratory infections– High fever, cough

• Diagnosis by immunoflourescence

Neisseria I• Diplococci diagnostic• N.gonorrhoeae – produces

urethritis –> cystitis -> pyelonephritis

• 80% males show signs• Female signs inconsistent• Dysuria, polyuria, pyuria• Ascending infections

– Vas deferens blocked– PID

• Systemic infections– Gonorrheal endocarditis– Gonorrheal arthritis– Eyes/pharynx – opthalmia neonate

Co-infections with Chlamydia

Neisseria II

• N. meningitidis – causes ~30% of childhood meningitis

• Initiates as throat infection -> sepsis -> meningitis

• Endotoxin effects to blood-brain barrier

• High mortality

Rhizobium

• symbiotic N2-fixer in the roots of legumes (clover, alfalfa, vetch, peas, beans)

• Expresses nitrogenase at low O2 tension in roots

• Reduces N2 NH2 for incorp into amino acids

• Major route for N into the biosphere

Root nodules on legume species

Agrobacterium

• associative N2-fixer• Plant pathogen – causes

“crown gall”• produced by Ti (tumor-

inducing) plasmid• Ti plasmid is used as a DNA

vector in biotechnology– nitrogenase genes– other genes