Gram-negative, Proteobacteria_20.pdf

Proteobacteria

• Proteus = many shapes

• Gram-negative

• Chemoheterotrophic

• Largest taxonomic group of bacteria

• Reorganized from 5 to now only 2 groups

Alphaproteobacteria

• Oligotrophs: most can grow with very low levels of nutrients

• Many have stalks or buds known as prosthecae

• Protomitochondria: ancestor of mitochondria

• N fixation, symbiotic relationship with plants

• Pathogenic (humans, plants)

Alphaproteobacteria - Purple nonsulfur bacteria

Genus Rhodospirillium and Genus Magnetospirillum

Genus Rhodospirillium

• Anoxygenic photosynthesis

•Metabolic flexibility

• Cyst formation: nutrient deprivation, NOT endospores, only resistant to desiccation

Genus Magnetospirillum

• Magnetotactic: magnetosomes to align with magnetic field

Alphaproteobacteria - Order Caulobacterales

• Genus Caulobacter

• Life cycle uses prostheca (stalks)

• Holdfast to attach to solid substrates (secretes strongest biological adhesive known)

Alphaproteobacteria - Order Rhizobiales

• Includes genera Rhizobium

• Symbiotically live in the soil with legume root nodules with N-fixing cells(bacteroids)

• Genus Agrobacterium

• Plant pathogens, enters through plant wounds

• Depends on Ti plasmid

Alphaproteobacteria - Brucellosis

• Brucella melitensis

• Human, animal pathogens

• Zoonatic disease

• Consumption contaminated animal products (like unpasteurized milk), abrasions on skin when handling animals

• Undulent: cyclic fevers, arthritis

Alphaproteobacteria and gammaproteobacteria - Nitrifying bacteria

• Oxidize ammonium or nitrite to gain energy and electrons

• Contribute to N cycle

• Chemolithoautotrophs

Order Pelagibacterales

• Pelagibacter (Genus)

• Unique: most abundant, in oceans, small genome

• Part of Earth's carbon cycle

Alphaproteobacteria -Rickettsias

• Rickettsia (Genus)

• ALL Obligate intracellular parasites, insect and tick bites

• Cause spotted fevers

• R. rickettsii: Rocky Mountain spotted fever

• Severe headache, fever,chills, skin rash hands/feet (damaged blood vessels)

Alphaproteobacteria: mitochondria ancestor

• Proteobacterial origin of mitochondria

Gammaproteobacteria - Order Burkholderiales

• Burkholderia (Genus)• Neisseria (Genus)• Bordatella (Genus)

Gammaproteobacteria - Order Burkholderiales • Burkholderia (Genus)

• Chemoheterotrophs ,chemolithotrophs

• Use substances released from organic decompositions

• Motile, disease in humans (pneumonias),plants (onions, tobacco)

• B. cepacia contamination of equipment/drugs in hospitals

• Issue for cystic fibrosis patients

Gammaproteobacteria - Order Burkholderiales • Neisseria (Genus)

• Inhabits mucous membranes (genitals, eyes, brain)

• N. meningitidis: cause of meningococcal meningitis

Gammaproteobacteria - Order Burkholderiales • N. gonorrhoeae

• cause of gonorrhea

• Acute, infectious STD

• Mucous membranes of genitourinary tract, eye, rectum, throat

• Use pili to attach to mucosal cells

• Some strains resistant to ALL antibiotic classes

• Men: discharge/pus, frequent urination

• Women: asymptomatic, PID, sterilitity, joints

• Conjunctivitis in newborns

Gammaproteobacteria - Order Burkholderiales• Bordatella (Genus)

• B. pertussis (whooping cough)

• Droplet transmission

• Nonmotile

• Targets respiratory epithelium (fever, malaise, uncontrollable cough, cyanosis)

• Highly contagious

• Pertussis toxin: increases mucus secretion

• Kennel cough in dogs

Gammaproteobacteria - Family Thiobacillaceae

• Obligate aerobes and facultativedenitrifiers (reduce nitrate tonitrogen gas)

• Control levels of sulfide in water draining from mines (bioremediation)

• Acid mine drainage inhospitable to most organisms

Gammaproteobacteria- Order Legionellales

• Legionella pneumophila (Legionnaire's disease)

• Found in streams, warm-water pipes, AC units, andcooling towers

• Prevent: chlorination, heating water

• Multiply in protozoa, human macrophages

Gammaproteobacteria- Order Coxiella

• Coxiella burnetii

• Q fever; transmitted via aerosols or milk

• DON'T CONSUME RAWMILK!

•Live outside host by forming resistant spore (heat,drying, disinfectant)

• Potential bioterrorism agent

Gammaproteobacteria- Order Pseudomonadales • species?

• Pseudomonas aeruginosa • Acinetobacter baumanii

Gammaproteobacteria- Order Pseudomonadales• Pseudomonas aeruginosa

• Human pathogen, resistant to most antibiotics, grow in antiseptics

• Opportunistic

• hospital-acquired infections

Gammaproteobacteria- Order Pseudomonadales• Acinetobacter baumanii

• Hospital-acquired• Invasive device• Immunosuppressed

• MDR infection

Gammaproteobacteria - Order Enterobacterales • Family?

Vibrionaceae and Enterobacteriaceae

Gammaproteobacteria - Order Enterobacterales • Family Vibrionaceae

• Found in aquatic habitats

• Bioluminescence (V. fischeri)

• Pathogen

• Vibrio cholerae cause scholera

• Food/water contamination

• 2010 Haiti resurgence

• Symptoms: profuse diarrhea,vomiting, leg cramps, die from dehydration/shock

Gammaproteobacteria - Family Enterobacteriaceae

• Escherichia (Genus)• Proteus (Genus)• Salmonella (Genus)• S. typhi • Klebsiella (Genus)• Shigella (Genus)• Serratia (Genus) • Yersinia (Genus)

Gammaproteobacteria - Family Enterobacteriaceae • Escherichia (Genus)

• E. coli: common inhabitant of GI tract, used in research labs

• indicator of fecal contamination

• causes foodborne disease and UTIs

Gammaproteobacteria - Family Enterobacteriaceae• Proteus (Genus)

• Swarming motility; colonies form concentric rings

• Moving like school of fish in same direction

• Opportunistic pathogen: UTI

Gammaproteobacteria - Family Enterobacteriaceae• Salmonella (Genus)

• 2,500 serovars

• Common form of foodborne illness

• Non typhoidal:

• Salmonella Enteritidis

• Gastroenteritis

• Abdominal pain, fever,cramps, nausea,vomiting

• contaminated water/food

Gammaproteobacteria - Family Enterobacteriaceae• S. typhi

•causes typhoidfever

• Enteric fever

• Person-to-person (Host restricted) from ingestion food/water contaminated infected feces

• Symptoms: rose spot rash, spread from epithelium to lymphoid, blood, liver, gallbladder, septic shock

• Some asymptomatic

Gammaproteobacteria - Family Enterobacteriaceae • Klebsiella (Genus)

• K. pneumoniae causes pneumonia (50% fatality), meningitis, UTIs, wound/skin infections

• Hospital-acquired, opportunistic (ventilators, catheters)

• Normally found in gut, skin (harmless)

• Increasingly resistant

Gammaproteobacteria - Family Enterobacteriaceae • Shigella (Genus)

• shigellosis

• Causes bacillary dysentery

• Acute inflammation of intestinal tract

• Fecal-oral

• Symptoms: fever,abdominal cramps,bloody, mucosal diarrhea

• Macrophages phagocytize, they kill them and invade epithelium

• Dehydrated, can't maintain blood pressure

Gammaproteobacteria - Family Enterobacteriaceae• Serratia (Genus)

• S. marcescens (opportunistic)

• Produces red pigment in colonies

• Common cause of nosocomial (hospital) infections (UTIs, respiratory infections)

• Catheters

Gammaproteobacteria - Family Enterobacteriaceae • Yersinia (Genus)

• Y. pestis causes plague, Black Death

• Transmitted via fleas from rats, squirrels

• Bubonic (swollen lymphnodes)

• Septicemic (multiply in blood)

• Pneumonic (air droplets)

Gammaproteobacteria - Order Thiotricales

• Francisella (Genus)

• F. tularensis: causes tularemia, "rabbit fever"

• associated with hiking; ticks, deer flies

• Rodents, rabbits, hares, cats are susceptible

• Depends on how bacteria enters the body