What type of bacteria is this? Shape: Bacillus Arrangement: Strepto- Colony Desc
ID: 173993 • Letter: W
Question
What type of bacteria is this?
Shape: Bacillus
Arrangement: Strepto-
Colony Description: Frosted white, grows quickly in comparison to others in my class, seems to spread out rather than taking on any elevation
Odor: Present
Gram Positive
Endospore positive
Positive for motility
Seems to be a facultative anaerobe. Used the oxygen at the top of the tube and was heavily concentrated towards the top, but seemed to still grow at lower levels of the tube without oxygen.
PEA Test: Positive
EMB: Negative
Beta hemolysis
Alkali(?) Litmus Milk Test
Catalase test: Negative
Nitrate Reduction: Postitve test
Indole test: Negative
Casein test: Positive
Negative for Glucose Lactose and Sucrose gas
Postitve for Glucose and Sucrose acid
Negative for lactose acid
Explanation / Answer
From the appearance of the bacteria shown above, the description of the bacterial colonies, its ability to produce endospores and its facultative anaerobe characters, this appears like Bacillus spp. But you have also stated that it is catalase negative, and the genus Bacillus is typically catalase positive. This is leading me to think that this may possibly be the genus Paenibacillus, which is very similar* to the genus Bacillus, and is typically catalase negative.*Paenibacillus literally means 'almost bacillus'.
The bacteria highly resemble the genus Streptobacillus, but Streptobacillus is typically Gram negative and non-motile.
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