Several individuals have food borne poisoning due to Salmonella from a common so

Question

Several individuals have food borne poisoning due to Salmonella from a common source. Later several individuals went 10 the local emergency rooms of the hospital complaining of similar symptoms. How could you determine and be sure that these individuals have the same infection? Distinguish between alpha-and beta-hemolysis? How would you differentiate between us and ? Why are females more prone to UTI than males? What would be the effect sample being left at room temperature overnight before transported to the laboratory for current?

Explanation / Answer

6. Salmonella causes enteric infection. Fecal sample from all the individuals can be collected and tested for the presence of Salmonella antigens. If all the individuals have the same infection, then all their specimens will test positive in the lab for the presence of same antigen of Salmonella.

7. Alpha-hemolysis is the partial lysis of RBC’s resulting in a greenisg color due to the presence of biliverdin, the breakdown by-product of haemoglobin. Alpha-hemolysis is due to the enzyme alpha-hemolysin produced by certain bacteria like Streptococcus pneumoniae. Beta-hemolysis is the process of complete breakdown of RBC and haemoglobin by the enzyme beta-hemolysin produced by certain bacteria like Staphylococcus aureus.

8. Staphylococcus aureus and Streptococcus pneumoniae can be differentiated by growing the bacteria on blood agar plate. Staphylococcus aureus is beta-hemolytic. It produces beta hemolysin that causes complete breakdown of RBC’s resulting in a lightened and transparent area around and under the colony. Streptococcus pneumoniae on the other hand is alpha-hemolytic. It produces alpha hemolysin that causes partial breakdown of RBC’s thus resulting in a dark and greenish area around and under the colony.

9. Females are more prone to UTI than males. As the urethra is shorter in females, bacteria need only to travel a shorter distance to reach the urinary bladder to cause an infection. Also, as the urethra is located near to the rectum in females, bacteria from the rectum can easily travel up the urethra and reach the bladder to cause an infection. Further, changes in the vaginal normal flora and pH due to the use of oral antibiotics, spermicides, menopause etc may also result in UTI causing bacteria to enter, survive and cause an UTI. Having sex can also cause UTI in women as the bacteria are pushed in to the urethra.

10. Culturing of urine sample being left at room temperature overnight before transported to the laboratory will give false results. It is because of the bacterial overgrowth that occurs in the urine when left at room temperature. As a result false results regarding the number of bacteria in the urine sample are obtained.

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