Question

In April 2004, a 37 year-old woman died of a mysterious skin infection that caused massive death of the connective tissue. She had been in the hospital for routine surgery in the day surgery unit. Another patient acquired the infection but the infection was milder and he lived. In addition, twelve other patients from the same day surgery as the previous two were shown to have the infection but also survived. Analysis of the specimens taken from the individuals showed gram positive coccus chains. It grew as beta-hemolytic and relatively sensitive to antibiotics including bacitracin. The infection control team tested the operating room personnel and none were shown to have the bacterium.

1. What is most likely the name of the disease causing this infection? What is the etiological agent?

2. Describe the bacterium. What are the characteristics of the pathogen that enabled it to cause this massive damage to a young healthy woman?

4.How do you think this patogen was transmitted?

5. What type of investigation would you have performed to discover the source of the pathogen?

Answer 1

1. The name of disease causing this infection is Impetigo. The etiological agent is Streptococcus pyogenes.

2. Characteristics of pathogen are- S.pyogenes is gram positive extracellular bacterium.These are non motile, non sporing cocci less than 2 micrometres in length.They form chains and large colonies greater than 0.5 mm in size. It has beta- hemolytic growth on agar.

4. This pathogen may transmitted via respiratory droplets, hand contact with nasal discharge and skin contact with that infected lady.

5. This infection is typically began in skin or throat.after detection of hemolytic colonies displaying S. pyogenes morphology, catalase test confirms that isolates represent streptococci.