Bacterial Survey – Gram negatives
2) 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 (tumorinducing) plasmid
• Ti plasmid is used as a DNA
vector in biotechnology
– nitrogenase genes
– other genes