Chapter 25: Mycoplasma and Ureaplasma. All Answers

MULTIPLE CHOICE 1. Mycoplasmas are a different type of bacteria because they do not have a: a. cell wall. b. cell membrane. c. nuclear membrane. d. messenger transporter. A Mycoplasmas are pleomorphic orga ...

MULTIPLE CHOICE 1. Mycoplasmas are a different type of bacteria because they do not have a: a. cell wall. b. cell membrane. c. nuclear membrane. d. messenger transporter. A Mycoplasmas are pleomorphic organisms that do not possess a cell wall, a characteristic that makes them resistant to cell wall–active antibiotics, such as the penicillins and cephalosporins. REF: 553 OBJ: Level 1: Recall 2. One of the factors that allows Mycoplasma to infect the respiratory tract and the urogenital tract is that: a. the body has a hard time detecting their presence, because they have no cell wall. b. they are virulent organisms. c. they adhere to the epithelium of mucosal surfaces and are not eliminated by mucus secretions. d. all of the above. C The mycoplasmas adhere to the epithelium of mucosal surfaces in the respiratory and urogenital tracts and are not eliminated by mucous secretions or urine flow. REF: 554 OBJ: Level 1: Recall 3. What disease causes the condition primary atypical pneumonia? a. Mycoplasma hominis b. M. urealyticum c. M. fermentans d. M. pneumoniae D M. pneumoniae may cause bronchitis, pharyngitis, or a relatively common respiratory infection known as primary atypical pneumonia or walking pneumonia. REF: 554 OBJ: Level 1: Recall 4. At-risk groups for contracting walking pneumonia include all the following except: a. prisoners. b. college students. c. military personnel. d. preschool children. D Mycoplasma pneumoniae causes approximately 20% of reported pneumonias in the general population and up to 50% in military settings. School-age children and young adults are especially susceptible to infection. Clinical disease is uncommon in very young children and older adults. Other groups at risk include closed-in populations, such as prisoners, college students, and military personnel. REF: 554 OBJ: Level 1: Recall 5. What two organisms are associated with urogenital tract infections but have also been isolated from asymptomatic individuals? a. Mycoplasma hominis and Ureaplasma urealyticum b. M. hominis and M. fermentans c. U. urealyticum and M. pneumoniae d. M. penetrans and M. pneumoniae A Both M. hominis and U. urealyticum are associated with infections of the urogenital tract. They are, however, frequently isolated from asymptomatic individuals, making interpretation of a positive culture difficult. REF: 555 OBJ: Level 2: Interpretation 6. When Mycoplasma hominis invades the upper genitourinary tract, it can cause: a. salpingitis. b. pyelonephritis. c. pelvic inflammatory disease. d. all of the above. D M. hominis is found in the lower genitourinary tracts of approximately 50% of healthy adults and has not been reported as a cause of nongonococcal urethritis (NGU). The organism may, however, invade the upper genitourinary tract and cause salpingitis, pyelonephritis, pelvic inflammatory disease, or postpartum fevers. REF: 555 OBJ: Level 1: Recall 7. What organism has been recovered in normal, sexually active females but is also associated with chorioamnionitis, congenital pneumonia, and development of chronic lung disease in premature infants? a. Mycoplasma hominis b. Ureaplasma ureolyticus c. M. penetrans d. M. fermentans B U. urealyticum has been recovered from more than 60% of normal, sexually active females and has been associated with reproduction disorders, chorioamnionitis, congenital pneumonia, and the development of chronic lung disease in premature infants. REF: 555 OBJ: Level 2: Interpretation 8. If a newborn has symptoms of meningitis but the cerebrospinal fluid (CSF) is negative for both Gram stain and a routine culture, what organisms should be suspected? a. Neisseria gonorrhea and Chlamydia trachomatis b. Treponema pallidum and Borrelia burgdorferi c. Mycoplasma hominis and Ureaplasma urealyticum d. M. pneumoniae and C. trachomatis C M. hominis and Ureaplasma spp. can be transmitted to the fetus at delivery and have been recovered from the CSF of certain high-risk newborns, including preterm and low-birth-weight babies. It has been recommended that culture for these organisms be attempted when the CSF specimen from a newborn with evidence of meningitis is negative for both Gram stain and routine bacteriology culture. REF: 555 OBJ: Level 2: Interpretation 9. When transporting specimens for Mycoplasma culture to the laboratory, extreme care must be taken so that the specimen does not: a. become contaminated. b. leak from the specimen container. c. become overgrown with bacterial normal flora. d. dry out. D Specimens for mycoplasmal culture include body fluids such as blood, synovial fluid, cerebrospinal fluid (CSF), wound aspirates, and respiratory secretions. Owing to the lack of a cell wall, all mycoplasmas are extremely sensitive to drying. REF: 557 OBJ: Level 1: Recall 10. What time frame is suitable for blood draws for serologic testing to diagnose Mycoplasma infections? a. Onset of symptoms and 2 to 3 weeks later b. Week after symptoms start and 2 months later c. Weeks after symptoms start and 3 months later d. Onset of symptoms and 2 months later A Optimally, serum samples for serologic testing should be collected at the onset of symptoms and 2 to 3 weeks later for acute and convalescent measurements. REF: 560 OBJ: Level 1: Recall 11. What test method is used to detect antibodies to Mycoplasma spp.? a. Complement fixation (CF) b. Enzyme immunoassay (EIA) c. Direct fluorescent antibody (DFA) d. Cellulose ion exchange (CIE) B Until recently, the most commonly used technique for demonstration of Mycoplasma pneumoniae antibodies was the micromethod CF assay, which was time-consuming and had inherent technical problems. EIA and micro-IF are now available for the detection of serum antibodies. REF: 560 OBJ: Level 1: Recall 12. All the following antibiotics are used to treat mycoplasma infections except: a. macrolides. b. fluoroquinolones. c. tetracyclines. d. penicillin. D Because they lack a cell wall, the mycoplasmas are inherently resistant to the -lactams: penicillins and cephalosporins. Mycoplasma pneumoniae has remained susceptible to the tetracyclines, newer fluoroquinolones, and the macrolides. REF: 561 OBJ: Level 1: Recall 13. Mycoplasma spp. from patient samples are visible by which staining technique? a. Gram stain b. Wright’s stain c. Acridine orange d. All of the above C Because they lack a cell wall, the mollicutes will not be visible by Gram staining. A DNA fluorescent stain (e.g., acridine orange) can be used, but this is not specific for the mollicutes. Mycoplasma-like colonies are stained with the Dienes or methylene blue stains. REF: 557 OBJ: Level 1: Recall 14. Which of the following methods is used to determine the presence of growth in mycoplasma broth media? a. Broth turbidity b. Presence of biofilm on surface c. Change in phenol red pH indicator d. Release of radiolabeled CO2 C Because Mycoplasma spp. do not produce visible turbidity in broth media, a pH indicator such as phenol red is added to detect growth. REF: 557 OBJ: Level 1: Recall 15. Which antibiotic is added to mycoplasma isolation and transport media to minimize bacterial contamination? a. Tetracycline b. Penicillin c. Erythromycin d. Gentamicin B Because they lack a cell wall, the mycoplasmas are inherently resistant to the -lactams: penicillins and cephalosporins. Penicillin is therefore added to transport and culture media to minimize bacterial contamination. REF: 557 OBJ: Level 1: Recall 16. Cultures for Mycoplasma pneumoniae should be incubated for: a. 2 to 3 days. b. 5 to 7 days. c. 10 to 14 days. d. 21 days or more. D M. pneumoniae colonies may take as long as 21 days to appear on culture media. REF: 558 OBJ: Level 1: Recall 17. Which of the following stains is used to enhance the visibility of mycoplasma-like colonies? a. Gram stain b. Acridine orange c. Dienes stain d. Wright’s stain C Because mycoplasma organisms do not stain with Gram stain, mycoplasma-like colonies are stained with the Dienes or methylene blue stains to enhance visibility. REF: 559 OBJ: Level 1: Recall 18. Mycoplasma organisms will grow in which of the following atmospheres? a. Ambient b. Capnophilic c. Anaerobic d. All of the above D Broth media is typically placed in atmospheric conditions, while solid agar media may be placed in 5% to 10% CO2 or an anaerobic atmosphere. REF: 558 OBJ: Level 1: Recall 19. Which of the following organisms was once called “T-strain mycoplasma?” a. Ureaplasma spp. b. Mycoplasma hominis c. Mycoplasma fermentans d. Mycoplasma orale A Ureaplasma spp. were once called T-strain mycoplasma because they form extremely small colonies on solid media. REF: 559 OBJ: Level 1: Recall 20. Which factor is added to media to provide cholesterol for mycoplasma-like organisms? a. Trypticase soy digest b. 20% fetal calf serum c. X and V factor supplement d. 5% sheep blood B Fetal calf serum is added to media to provide a source of cholesterol required for synthesis of cell membranes. REF: 559 OBJ: Level 1: Recall