Question

Please list the term that matches the description.

1. Staphylococcus aureus secretes this protein which punches holes in red blood cells. _______

2. Means “Living together”. _______

3. Degree of pathogenicity. _______

4. Hospital acquired infections that arise from a patient’s normal microbes in a health care setting.  _______

5. Lipopolysaccharide of Gram negative bacteria. _______

6. When both symbionts benefit from their interaction. _______

7. A second stage of infection disease, which is short with generalized mild symptoms. _______

8. Formerly called nosocomial infections. _______

9. Another word for disease. _______

10. A symbiont that benefits without significantly affecting the other. _______

Answer 1

1. Hemolysin

Bacteria producing haemolysin (like Staphylococcus), can cause partial or complete lysis of RBC. Different types of haemolysis are:

• Alpha haemolysis: greenish- discoloration around the colony. Partial Haemolysis.
• Beta Haemolysis: Complete haemolysis. Zone of clearing around colonies.
• Gamma haemolysis: no haemolysis observed. Colonies may appear on media.

2. Symbiosis

• The word “Symbiotic” in Greek, means living together.
• It involves interaction like mutualism, commensalism or antagonism (parasitic) relationship between two unrelated organisms.

3. Virulence

• The capacity of a pathogenic organism to cause disease is called as the pathogenicity.
• The gegree of pathogenicity is the virulence for the organisms. It is related to virulence factors possessed by the organism

4. Nosocomial

• In immunocompromised people, severe infection may result, mostly in form of nosocomial infections (hospital related).

5. Endotoxin (LPS)

• LPS or lipopolysachharide layer is present in outer membrane of Gram negative bacteria.
• The comprise of the O-antigen or endotoxin.
• They are integral part of the bacteria.
• They can be released only when the bacteria die. Example E. coli, Salmonella typhi.