Exam 1 Micro-Organisms

Question 1

-Rhodospirillum rubrum-

Answer 1

• Gram negative
• spiral shaped
• facultative anaerobic
• found in aquatic environments
• causes ringworm, nail fungus, and athletes foot

Question 2

-Escherichia coli-

Answer 2

• Gram negative
• rod shaped
• facultative anaerobes
• non-spore forming
• can ferment lactose
• found in mammalian intestinal tract
• E. coli 0157:H7 Shiga toxins - associated with beef

Question 3

-Enterobacter aerogenes-

Answer 3

• Gram negative
• rod shaped
• facultative anaerobe
• catalase positive
• found in the human gastrointestinal tract
• Infections commonly attributed to E. aerogenes are respiratory, gastrointesntinal, and urinary tract infections, specifically cystits, in addition to wound, bloodstream, and central nervous system infections. The species most commonly associated with adult cases of meningitis.

Question 4

-Proteus vulgaris-

Answer 4

• Gram-negative
• rod shape
• facultative anaerobe
• catalase-positive
• highly motile
• nitrate-reducing
• hydrogen sulfide-producing
• inhabits the intestinal tracts of humans and animals. It can be found in soil, water, and fecal matter.
• causes hospital infections such as UTI

Question 5

-Serratia marcescens-

Answer 5

• bacteria in the family Enterobacteriaceae)
• Gram negative
• rod shaped
• Facultative anaerobic
• motile
• reddish growth on bathrooms and other surfaces
• involved in nosocomial infections, particularly catheter-associated bacteremia, UTI infections and wound infections (responsible for 1.4% of nosocomial bacteremia cases in the US.)

Question 6

-Moraxella catarrhalis-

Answer 6

• Gram negative
• spherical pairs (diplococcus)
• aerobic
• oxidase-positive
• found as a commensal of the upper respiratory tract

Question 7

-Alcaligenes faecalis-

Answer 7

• Gram negative
• rod shaped
• obligate aerobe
• motile
• non-nitrate reducing
• catalase and oxidase positive
• alpha hemolytic
• citrate positive
• found in feces and soil (environment)
• infections usually occur in the form of UTI

Question 8

-Bacillus cereus-

Answer 8

• Gram positive
• Rod shaped
• facultative anaerobic
• beta hemolytic bacterium
• spore forming
• found in soil and food
• causes food poisoning

Question 9

-Lactococcus lactis-

Answer 9

• Gram positive
• spherical pairs and short chains
• facultative anaerobe
• non spore forming
• non motile
• used in dairy

Question 10

-Enterococcus faecalis-

Answer 10

• Gram positive
• spheres in clusters, short chains, diplococci and single cocci
• facultative anaerobes
• non-hemolytic
• found normally in the intestines of humans, animals and birds. It is also found in soil and water in nature.
• causes life threatening illnesses such as meningitis, UTI, bacteremia, endocarditis (resistant to antibiotics)

Question 11

-Staphylococcus epidermidis-

Answer 11

• Gram positive
• clustered spheres
• facultative anaerobic
• Biochemical tests: coagulase -, catalase +
• lives on healthy human skin and mucosal surfaces
• common cause of infections involving indwelling foreign devices, surgical wound infections, and bacteremia in immunocompromised patients.

Question 12

-Bacillus subtilis-

Answer 12

• Gram positive
• rod shaped
• strict aerobe
• endospore forming
• Catalase positive
• found in soil and guts of human and cows
• Does not normally cause sickness

Question 13

-Bacillus megaterium-

Answer 13

• Gram positive
• rod shaped
• aerobic
• endospore forming
• found in soil
• causes bacteremia, sepsis, meningitis
  (amongst the biggest known bacteria)

Question 14

-Micrococcus luteus-

Answer 14

• Gram positive
• round and clustered
• obligate aerobe
• urease +, catalase +
• found in soil, dust, water and air, and as part of the normal flora of the mammalian skin.
• can cause septic shock, pnuemonia, and urinary tract infections in an immune-deficient person.

Question 15

-Mycobacterium phlei-

Answer 15

• Acid-fast positive
• rod shaped
• found in soil
• causes infection in feet tendons, produces positive TB tests