Which of the following
does not characterize Neisseria gonorrhea:
A. grows well in cold temperature
B. culture can be done by Thayer Martin medium
C. gram negative diplococci
D. DNA probe can be used for rapid diagnosis
E. can cause septic abortion and premature rupture of membrane
Answer
Which substance in the outer membrane of gram negative bacteria is a potent endotoxin (released when the bacteria die)?
peptidoglycan
lipid A component of lipopolysaccharide
lipoproteins
antigenic polysaccharides
Answer
A 24-year-old woman in her third trimester of pregnancy presents with urinary frequency and burning for the past few days. She denies fever, nausea, vomiting, or chills. She takes no medications besides prenatal vitamins and is generally in good health. Physical examination is remarkable for mild suprapubic tenderness, and a urine dipstick is positive for white blood cells, protein, and a small amount of blood. Culture produces greater than 100,000 colonies of gram-negative bacilli. which of the following attributes of this uropathogenic organism is most strongly associated with its virulence?
A. Bundle-forming pili
B. GVVPQ fimbriae
C. Heat labile toxins
D. Heat stable toxins
E. P pili
F. Type 1 pili
Answer
An archaeologist who has been excavating a very old Middle Eastern site develops a pustule on his hand. The pustule then ruptures to form a black eschar surrounded by expanding brawny
edema. Which of the following organisms is the most likely cause of this condition?
A. Bacillus anthracis
B. Borrelia burgdorferi
C. Francisella tularensis
D. Spirillium minus
E. Yersinia pestis
Answer
Regarding Gonorrhoea which is incorrect:
a. Is caused by a bacterium
b. Can only be treated with penicillin
c. If untreated, can occasionally lead to infertility
d. Is frequently asymptomatic in women
Answer
Which of the following are trimeric proteins in the bacterial outer membrane that control the passage of large molecules, including some antibiotics, into and out of the cell?
A. lipopolyscacchride
B. porins
C. transpeptidases
D. pili
E. fibrillae
Answer
Which one of the following is not an arbovirus?
A. Ross River virus
B. Murray Valley encephalitis virus
C. Barmah Forest virus
D. Human papillomavirus
E. Dengue virus
Answer
Which of the following is the causative agent of lymphogranuloma venereum?
A. B.(Rochalimaea) henselae
B. E. chaffeensis
C. C. trachomatis
D. R. rickettsii
E. C. burnetii
Answer
Which one of the following organisms normally inhabits the healthy human oral cavity?
A. M. hominis
B. M. orale
C. M. pneumoniae
D. M. fermentans
E. U. urealyticum
Answer
Which of the following mycoplasmas has been implicated as a cause of nongonococcal urethritis (NGU)?
A. Mycoplasma hominis
B. M. pneumoniae
C. M. fermentans
D. M. mycoides
E. Ureaplasma urealyticum
Answer
A man with chills, fever, and headache is thought to have "atypical" pneumonia. History reveals that he raises chickens and that approximately 2 weeks ago he lost a large number of them to an undiagnosed disease. Which of the following is the most likely diagnosis of this man's condition?
A. Anthrax
B. Q fever
C. Relapsing fever
D. Leptospirosis
E. Ornithosis (psittacosis)
Answer
Which one of the following antibiotics binds to penicillin-binding protein-2 (PBP-2)?
A. Penicillin
B. Amdinocillin
C. Amphotericin
D. Chloramphenicol
E. Trimethoprim
Answer
Which one of the following antibiotics inhibits dihydrofolate reductase?
A. Penicillin
B. Amdinocillin
C. Amphotericin
D. Chloramphenicol
E. Trimethoprim
Answer
Which of the following is a quinolone antibiotic with broad Gram-negative and Gram-positive activity?
A. Piperacillin
B. Cefoperazone
C. Ceftriaxone
D. Ciprofloxacin
E. Imipenem
Answer
DNA from a host sample can be amplified by a process known as the polymerase chain reaction (PCR). Which of the following is required for PCR?
A. Knowledge of the genetic sequence to be amplified
B. An single nucleotide primer
C. An ultracentrifuge
D. A universal probe to detect the amplified product
E. A heat-sensitive DNA polymerase enzyme
Answer
Early attempts at the polymerase chain reaction (PCR) used E. coli DNA polymerase. This was replaced with DNA polymerase from Thermus aquaticus ("Taq" polymerase). Which of the following is the primary advantage in using this enzyme?
A. It is cheaper than E. coli polymerase
B. Specificity is increased because nonspecific hybridization of primers does not occur
C. Use of Taq polymerase results in fewer PCR cycles
D. Use of Taq polymerase enables lower temperatures to be used
E. Upon repeated cycling, Taq polymerase becomes denatured, which causes less interference with the hybridization process
Answer
Certain enzymes catalyze the cross-linking of peptidoglycan, a unique constituent of bacterial cell walls. Which of the following may be a factor in antibiotic resistance, the target of which is cell-wall synthesis?
A. Bactoprenol
B. Reverse transcriptase
C. RNA polymerase
D. DNA gyrase
E. Penicillin-binding proteins (PBPs)
Answer
Reversion of Neisseria gonorrhoeae from a fimbriated (fim 1) to a nonfibriated (fim 2) state would result in which one of the following phenomena?
A. Inability of N. gonorrhoeae to colonize the mucosal epithelium
B. Reversion to a Gram-positive stain
C. Death of the organism
D. Loss of serologic specificity
E. A negative capsule strain
Answer
The formation of adenosine triphosphate (ATP) is essential for the maintenance of life. In mammalian systems, the number of moles of ATP formed per gram atom of oxygen consumed (the P/O ratio) is 3; in bacteria, however, the P/O ratio may be only 1 or 2. Which of the following is the primary reason for the lower P/O ratio in bacteria?
A. Absence of nicotinamide adenine dinucleotide (NAD)
B. Loss of oxidative phosphorylation coupling sites
C. Less dependence on ATP as an energy source
D. Absence of a nonphosphorylative bypass reaction
E. A less-efficient mesosome
AnswerTags:
MCQ, Microbiology, ATP
An aliquot of Escherichia coli is treated with ethylenediaminetetraacetic acid (EDTA). The first wash is analyzed and found to contain alkaline phosphatase, DNase, and penicillinase. Which of the following anatomic areas of the cell is most likely to have been affected by the EDTA?
A. Periplasmic space
B. Mesosomal space
C. Chromosome
D. Plasma membrane
E. Slime layer
Answer
