QuestionSBA
QuestionChoice
This is also an aerobic gram-positive bacteria. However, the cocci are arranged in pairs or 'string of beads'.

Just think of strep as in strip - they arrange themselves into strips.
10005768
c
*Streptococcus pyogenes*
QuestionChoice
This is an aerobic, gram-positive organism which is arranged in clumps of spheres/ cocci. However, this would test negative on a coagulase test.

The coagulase test is done by identifying the presence of bound coagulase or clumping factor on the wall of the bacteria.

Coagulase-negative Staphylococci commonly live on the skin and don't tend to cause infection unless someone is immunocompromised.
10005769
d
*Staphylococcus Epidermis*
QuestionChoice
This is a gram-negative bacteria.
10005770
e
*Neisseria Gonnorhoea*
QuestionChoice
This is an Aerobic, gram-positive organism which is arranged in clumps of spheres/ cocci.

This is the most common cause of septic arthritis. The main aim of this question is to identify which bacteria are gram-negative/ positive and which are aerobic and anaerobic. You are not expected to know about septic arthritis.
10005766
a
*Staphylococcus Aureus*
QuestionChoice
This is a gram-negative bacteria that cause UTI. This bacteria can also cause septic arthritis but is ruled out by the joint culture.
10005767
b
*Escherichia coli*
Concept
Chapter
2693
3956
Gram Staining
Topic
148
Microbiology
13700
A 60 year old diabetic female presents to the GP with a 3-day history of a red, swollen, painful right knee.

On examination, there is limited movement in the knee due to the pain associated. The GP notices that it is warm to touch as he tries to mobilise it.

She is systematically well and there are no signs of sepsis.

The GP suspects septic arthritis.

Joint aspiration is carried out and was sent for Gram stain, leucocyte count, polarising microscopy and fluid culture.

Fluid culture shows aerobic gram-positive cocci in clumps. A coagulase test is carried out which is positive. What organism is this likely to be?
a