49 TO ANSWER ITEMS 6-49 THROUGH 6-53, SELECT FROM THE ABOVE LIST THE CONDITION MOST PROBABLY CAUSED BY THE AGENT LISTED IN THE QUESTION. 6-49. Bordetella pertussis. 1. A 2. C 3. E 4. F 6-50. Streptococcus pneumoniae. 1. A 2. B 3. C 4. E 6-51. Yersinia pestis. 1. B 2. C 3. D 4. E 6-52. Clostridium perfringens. 1. A 2. C 3. D 4. F 6-53. Staphylococcus aureus. 1. A 2. D 3. E 4. F 6-54. In the Gram’s stain procedure, which of the following chemicals acts as the mordant? 1. Crystal violet 2. Safranin 3. Iodine 4. Acetone 6-55. All of the following statements are true about antigens EXCEPT that an antigen 1. is inherently unstable structurally 2. must be foreign to the body 3. possesses a high molecular weight 4. has a high specificity to stimulate tissues to produce antibodies 6-56. The Rapid Plasma Reagin test for syphilis is best used with what type of specimen? 1. Serum 2. Plasma 3. Whole blood 4. Either serum or plasma A. Impetigo B. Plague C. Pneumonia D. Gas gangrene E. Strep throat F. Whooping cough