Gram -

Question 0

Spirochete general characteristics

Answer 0

Live under various conditions, many are Aerobic, other are facultative anaerobic, and others live anaerobic. Gram -, penicillin sensitive.

Question 1

Spirochete general description

Answer 1

Coiled bacteria, located in soil,in sewage and decaying matter and in human and animal body.
Do not use flagella , use axial filament located between the outer sheath and the body of the spirochete. Axial filament rotate the cell rotate the opposite direction and moves through liquids.

Question 2

Spirochete human pathogens

Answer 2

Treponema : T. pallidum :syphilis (transmitted by arthropods)
Borrelia : relapsing fever , Lyme disease (tick borne)(transmitted by arthropods)
Leptospira : leptospirosis , it’s a blood disease( passed through urine/water)

Question 3

Important differences between spirochete and spirilla ?

Answer 3

Spirilla are helical bacteria resembling spirochete but they don’t have axial filaments. They posses flagella for motility. They are Gram - helical bacteria

Question 4

Distinguish characteristic of Spirilla

Answer 4

Spirilla are commonly found in aquatic environment. Some can be unusually long, reaching up to 60m in length. Azospirillum lives in close association with many plants where it fix nitrogen.
Aerobic/microaerophilic
Fecal/oral transmission

Question 5

Pathogenic spirilla

Answer 5

Campylobacter jejuni: Gastroenteritis( intestinal disease) accompanied by diarrhea and transmitted by contaminated milk, water and food.
Helicobacter pylori: stomach ulcers in humans, comma shaped or “s” shaped rigid cells , free living, isolated from water/feces, motile by polar flagella ( often amphitrichous)
Spirillum minor : rat bite fever, a blood disease transmitted during a rodent bite.

Question 6

Compare vibrios with other spirochete

Answer 6

Certain helical bacteria are referred to as Vibrios, Gram -, curved bacteria, resembles commas.
Vibrio cholerae: agent of cholera, serious intestinal disease with extensive diarrhea.
Bdellovibrio: ability to multiply within other bacteria

Question 7

General characteristic of Pseudomonas

Answer 7

Gram - , single rods, aerobic,flagella occurring at the poles ( lophotrichous) found in soil, water and plants. Highly resistant to chemicals and antibiotics, carry multiple resistance plasmids. Many contaminate and survive in hospital equipments(I.V. tubing, dialysis machines, water lines …). Metabolizes ,many unusual organic compounds(jet fuel, oil, soap, disinfectant). Cause of burn infections, septicemia
Pseudomonas aeruginosa : produces serious infection in humans. Sensitive to gentamycins and silver compounds. Use nitrogen as final electron acceptor. Produces blue-green pigment in burnt tissue detected by UV light.

Question 8

Legionella

Answer 8

Rods, single or in pairs, fastidious, found in water and equipment which is in contact with soil and water mist or vapor(A/C units, cooling towers, hot water lines, humidifier....) 
Very fastidious ( very picky) activated charcoal is their favorite medium.

Question 9

Brucella

Answer 9

Causative agent of Brucellosis.
Gram-, rods, nonmotile, coccobacilli, zoonotic/epizoonotic (parasites of humans and animals, cattle, goats,pigs,dogs). relatively common in animals, especially cows, pigs and sheep. Transmitted to human in contaminated meat and animal products and they cause undulant fever. Sensitive to tetracycline and streptomycin.
B. melitensis : undulant fever in goats
B.abortus : cattles
B.suis: swine and hogs
B. canis

Question 10

Rhizobium

Answer 10

Most important Gram - rods in agriculture, symbiotic, they live on the roots of legume plants ( peas, beans, alfalfa and clover) where they fix nitrogen. They trap nitrogen from air and fix it into nitrogen compound the plants can use. Plants for amino acid form nitrogen and become rich in protein. Source of food for all animals and humans.

Question 11

Compare Azetobacter and Rhizobium

Answer 11

Azotobacter and Rhizobium both nitrogen fixing. Azotobacter live free in soil. And trap soil nitrogen and make it available for plants. They are key element in nitrogen cycle of soil. Azomonas gram - rods are the same as azotobacter.

Question 12

Bordetella pertussis

Answer 12

Agent of whooping cough, colonizes nasopharynx and trachea in humans.

Question 13

Neisseria

Answer 13

Gram -, aerobic/microaerophilic, diplodocus, parasites of human mucous membrane, reproductive tracts and nervous system. Penicillin and cephalosporin sensitive. Growth in candle jar.

Question 14

Neisseria Pathogen

Answer 14

N.gonorrhea : sexually transmitted gonococcal urethritis

N. meningitidis: meningococcal meningitis (airborne),

Question 15

Bordetella

Answer 15

Nonmotile bacilli , capsules formed.

Erythromycin sensitive. Vaccine available

Question 16

Family Enterobacteriacea

Answer 16

Intestinal flora ( “enteric bacteria”, “coliforms”), inhabit intestine of humans and animals, many are motile, most ferment glucose , posses pili(fimbrae), may interchange plasmids, causes endotoxins. This group includes commensals, opportunistic pathogens and primary pathogens.

Question 17

Enterobacteriacea pathogens

Answer 17

Escherichia: E.coli
Citrobacter: opportunistic pathogen
Enterobacte: opportunistic
Klebsiella: opportunistic
Proteus: opportunistic
Salmonella: intestinal pathogen
Shigella: intestinal pathogen
Yersinia: bubonic plague

Question 18

Pseudomonas aeruginosa

Answer 18

In soil, plants, skin, cause of burn infection, septicemia( bacteria replicating in blood stream, producing endotoxins ), psychrophiolic, fluorescent pigmented under UV, multiple flagella

Question 19

Legionella pathogen e.g.

Answer 19

L. pneumophila: opportunistic pathogen, causing fatal pneumonia in immunocompromised individual. Sensitive to tetracycline.
Found in water/devices/fixtures containing water

Question 20

Citrobacter e.g.

Answer 20

C.freundii
Common cause of urinary tract infections, often multiply drug resistance, like citrate acid , treatment: nitropherontone, trimethylsulfa…

Question 21

Escherichia e.g.

Answer 21

E.coli : lives in the intestine of animals and humans. Some strain cause urinary infection and gastroenteritis. Main causative agent of opportunistic / nosocomial infection. Hospital acquired infection. Tetracycline/erythromycin/ampicillin sensitive.

Question 22

Serratia marcescens

Answer 22

Opportunistic pathogen, produce red colony pigment, frequently associated with nosocomial infection. May cause urinary and serious respiratory infections in weakened hosts. May colonize catheters, saline solution and other similar objects.
NOT sensitive to ampicillin.

Question 23

Enterobacteriacea e.g.

Answer 23

Enterobacter aerogenes : nosocomial pathogen, causes septicemia and pneumonia , mucoid colonies due to think capsules

Question 24

Klebsiella e.g.

Answer 24

Klebsiella pneumoniae : sometimes mistaken for Enterobacter, it forms capsule, produces distinct capsules and mucoid colonies. Frequent opportunistic nosocomial pathogen, causes pneumonia and septicemias which may be potentially fatal. Attack lungs

Question 25

Proteus e.g.

Answer 25

P. vulgaris, P.mirabilis
Frequent cause of opportunistic and nosocomial urinary, wound and respiratory infection, highly motile, “swarming” colonies, perithricous flagella

Question 26

Salmonella e.g.

Answer 26

Primary pathogen, cause gastroenteritis, salmonellosis, typhoid fever. Incapable of lactose fermentation, produce hydrogen sulfide. Many species are I.D. By antibody testing (serovars).
S.typhi : typhoid , S. Dublin : in Ireland , S. Arizona
Some colonize hosts and produce carrier states(typhoid Mary).
Transmitted by fecal contamination of food and water , flies, raw milk,meats and poultry( including eggs).
Ampicillin / chloramphenicol / trimethoprim sensitive.
Destroy by boiling or cooking at above 170 F.

Question 27

Shigella e.g.

Answer 27

Similar to salmonella in non-utilization of lactose.
Pathogens include : Shingella sonnei, Shingella flexneri, Shingella dysenteriae.
Causative agent of shigellosis( basically dysentery)
Transmitted by same routes as salmonella.

Question 28

Yersinia e.g.

Answer 28

Y.pestis : flea borne bubonic plague and airborne pneumonic plague. Spread by rodent fleas, pandemic disease, rare today.
Y.enterocolita : gastroenteritis transmitted by raw/improperly cooked meats, vegetables and raw milk.

Question 29

Vibrio Human pathogen

Answer 29

Free living in fresh and salt water, comma shape bacilli,motile, monotrichous flagella.
Vibrio cholerae : causative agent of cholerae transmitted by contaminated water/food.
Vibrio parahaemolyticus and V. Vulnificans: cause gastroenteritis , food intoxications acquired by eating raw or uncooked shellfish.

Question 30

Pasteurellaceae

Answer 30

Rod shape, pleomorphic, parasitize animals and humans.
Pasteurella :Pathogen of cattle, fowl, cats and dogs. Facultative anaerobic .
Pasteurella multocida : may cause epizoonotic infections via animal bites ( e.g.cats)
Hemophilus: H.influenzae: may inhibit nasopharynx, vagina and intestines of humans. Produce meningitis, otitis, bronchitis, pneumonias. Required hemolyzed blood in culture medium for growth. Rifampin sensitive. Vaccine available (Hib).
Gardnerella: Pleomorphic, G.vaginalis : cause of the most common vaginitis infection. Not STD, result from pH change, overgrowth of flora, lack of antagonistic flora.

Question 31

Bacterioides

Answer 31

Anaerobic bacteria, responsible for serious infections following surgery, puncture wounds, and animal and human bites. Anaerobic bacteria found in intestines and mouths of humans and animals.
B. fragilis

Question 32

Rickettsias/Ehrlichia

Answer 32

Completely parasitic. Primarily arthropod borne ( fleas, lice and ticks), multiply in bloodstream and cause Hugh fevers, rashes and collapse. Obligate intracellular parasites, nonmotile, pleomorphic , incapable of ATP synthesis
Tetracycline and doxycycline sensitive

Question 33

Rickettsia e.g.

Answer 33

R. Prowazekii and R. Typhi : cause typhus
R. Rickettsii : causes Rocky Mountain spotted fever
Tetracycline and doxycycline sensitive

Question 34

Ehrlichia e.g.

Answer 34

E. chafeensis : causes human granulocytic ehrlichiosis

Tetracycline and doxycycline sensitive

Question 35

Chlamydia

Answer 35

Pathogens of humans and birds.
Sensitive to Tetracyclines / Erythromycin
C. Trachomatis: leading cause of non-gonococcal urethritis ( sexually transmitted)
C.psittaci: causes a serious pneumonia in birds(parrot-fever) which may be contracted by humans handling birds or exposed to bird droppings.