Question

A women is brought to the ER where you are working triage. She has an extremely swollen right lower leg. You see what appears to be an old surgical wound in the mid-calf, with rough scar tissue surrounded by purplish-red skin. She is in a lot of pain and her husband speaks for her. He tells you that three weeks ago she had a group of moles removed from that area. It had appeared to heal initially, but three days ago the incision area started looking bigger rather than smaller. She did not return to the physician, hoping the condition would resolve itself. In the past three days the area has begun to swell and become very hot. You call the attending physician immediately because you know that this is a serious condition.

The patient is sent straight to surgery where the wound is debrided. Gram-positive cocci growing in chains are recovered from the wound. She is transferred to intensive care and put on high-dose intravenous antibiotics for the next 18 hours, but the next evening her leg is amputated below the knee. She remains in the hospital for two months following surgery and requires long-term antibiotic therapy and multiple skin grafts on her upper leg.

1. What condition did this patient have? What organism caused it? Provide your rationale. (5 pts)
2. Why was amputation the best solution for the infection in this case? (3 pts)
3. How is the organism transmitted? How might the patient have contracted it? (2 pts)
4. If the organism gets into blood, what other condition would doctors become concerned about? What virulence factors contribute to this condition – explain their mechanism of action and how it contributes to the disease condition. (4 pts)

Answer 1

1. This patient have condition called as Osteomyelitis and organism which caused this condition is staphylococcus aureus.

Because Osteomyelitis is an infection mainly caused by gram positive bacteria staphylococcus aureus in long bone , vertebrae or clavicle due to contaminated surgical procedure , cut , wound or trauma . In this patient have infection with cut in long bone as in mid thigh and bacteria which was found is gram positive cocci thus most probably patient have osteomyelitis caused by staphylococcus aureus.

2. Amputation is best solution for infection in this case because it lead to absence of remission of osteomyelitis till 1 year and thus reducing risk of multiple amputation in patient. Also reduce the risk of spread of infection (organism) to different organ through blood stream leading pneumonia , endocarditis and septicemia or septic shock. So amputation is best solution.

3. This organism staphylococcus aureus is mainly transmitted through blood stream , it is also normal flora present over skin but due to trauma and contaminated blade it can spread to long bone and in bloodstream causing bacterisepsis in blood and osteomyelitis which is debilating bone infection.

Patient may have contracted it by taking antibiotics orally , cleaning wound through aseptic solution , using topical antibiotic on cut to kill organism thus avoiding the spread of organism and thus reducing risk of infection .

4. If organism get into blood , which is staphylococcus aureus it may have caused pneumonia in patient as it spread through bloodstream may have caused bacteremia or bacterial sepsis in blood and endocarditis may also occur in heart. Thus doctors will be concerned about spetic shock and sign and symptoms of it , pneumonia and endocarditis.

5. Virulence factor which contributes to this condition is of staphylococcus aureus - surface antigens adherence on type 1 collagen and endotoxin , and glycocalyx .

Their mechanism of action as it spread through bloodstream , bacteria reaches the metaphysis of rapidly growing bone and provokes an inflammatory response. Surface antigen play important role in bacterial adherence to type 1 collagen and endotoxin that suppress local immune response . Also glycocalyx may form around bacteria and may enhance adherence of other bacteria and metallic implants. Due to which acute inflammatory response occur causing tissue necrosis and breakdown of bone leading to obstruction thus causinh avascular necrosis and tissue death , leading to sequestration formation , hence chronic osteomyelitis.

PLEASE UPVOTE IF YOU FIND IT SATISFACTORY. COMMENT IF ANY DOUBT.