Question

A 53-year-old male farmer presents for evaluation of a growth on his arm. About a week ago, he noticed some mildly itchy red bumps on his arm. They started to blister a day or two later and then ruptured. During this time he had a low-grade fever, but otherwise felt well. Further questioning reveals that he has had no ill contacts and never had anything like this before. He has cows, horses, goats, sheep, and chickens on his farm. On examination of his right upper arm, you find a 4.5-cm circular black eschar surrounded by several vesicles (blisters) and edema. He has tender axillary lymph node enlargement (adenopathy). A Gram stain of fluid drained from a vesicle and a biopsy from the eschar both show chains of gram-positive bacilli on microscopy.

Based on the information presented in the case study, answer the following questions:

1. What microorganism or virus do you believe is to blame for the man’s illness?

2. What information from the patient’s symptoms contributed to your decision?

3. What information from the patient’s history contributed to your decision?

4. Based on what you know about this microorganism or virus, what steps can be taken to treat the illness?

5. What are the primary virulence factors of this organism?

Answer 1

Organism:
Staphylococcus Aureus: This bacteria commonly found on the skin or nose,lung,heart etc..It make symptoms like boils,pus formation,skin ulcer,rash and fever
Patient symptoms:
Blister, low grade fever, 4.5cm circular black eschar,edema, axillary lymph nodes enlargement(adenopathy)
Patient history:
patient having a history of blister one week ago which cause skin infection..Patient has farm house for cows,horse,goat,sheep and chicken..
Treatment:
-Antibiotics like clindamycin,linezolid
-Vancomycin antimicrobial therapy
- debridement
- Isolation
- Aseptic precautions
Virulence factors:
-colonization of host tissue by surface proteins
- Invasion can spread bacteria to tissue
- surface factors inhibit the phagocytic engulfment
- Biochemical properties (catalase production)
-Immunological variation
-Membrane damaging toxins like leukotoxin,hemolysins
- Host tissue damage by exotoxins which produce the symptoms
- Resistance to antimicrobial agent