Question

Question 1 (1 point) An unknown organism was inoculated into a phenol red tub and produce a yellow coloration. The same organism was inoculated into a purple broth tube resulted in growth after the incubation period. Green slant tubes were also inoculated and resulted in a blue coloration. However, this organism was negative for motility within a SIM tube. Which of the following is the unknown species? Salmonella typhimurium Shigella sonnei Enterobacter aerogenes Klebsiella pneumoniae Escherchia coli O Proteus mirabilis Serratia marscecens

Answer 1

Answer 1:
Option - Klebsiella pneumoniae

Klebsiella pneumoniae is lactose fermenter, citrate positive and non-motile.
Other choices given don't have this combination of results.

Answer 2:
Option - 1st option indicates Escherichia coli

Escherichia coli will give following combination of results:
LDC - Pos
H₂S- Neg
Indole - Pos
Lactose - Pos
Urea - Neg
citrate - Neg
Motility - Pos
Colour pigment at 25^oC - Neg
Chromagar colour - Purple.

Answer 3:
Option - Produces H₂S in SIM tube; Produces the enzyme urease

Proteus mirabilis is lactose non-fermenter, motile and does not give indole test positive. On Chromagar it gives a brown halo.

Answer 4:
Option - Klebsiella pneumoniae

Klebsiella pneumoniae is lactose fermenter, non-motile and gives citrate positive and Indole negative.

Answer 5:
Option - Pseudomonas

Pseudomonas gives many tests negative as they are aerobes and do not ferment sugars under anaerobic conditions,
_{[Please note, that information given is insufficient to give name of the organism, this one is to the best of my knowledge.]}

Answer 6:
Option - Serratia marcescens

This organism is urease negative and produces a red coloured pigment on incubation at 25^oC.

Answer 7:
Option - following test results show the organism to be Salmonella typhimurium

- Positive for Lysine Decarboxylase
- negative for indole and lactose
- shows motility

Salmonella typhimurium is positive for citrate but not for urease, it produces H₂S,

Answer 8:
Option - False

Klebsiella pneumoniae can cause UTI but only in complicated cases, catheterization of patients, nosocomial infection, etc. In general most UTI are caused by Escherichia coli.

Answer 9:
Option - False.

Most E.coli are nonpathogenic and ferment sorbitol exception being enteropathogenic like  E. coli O157:H7

Answer 10:
Option - True.

Most strains of Pseudomonas produce water soluble pyocyanin pigment.