The Quizzes about Bacteriology – Part 2

The laboratory reports that the Venereal Disease Research Laboratory (VDRL) test performed on the above patient is reactive at a dilution of 1:4 (4 dils). The patient also reports to you that he has recently been diagnosed with hepatitis A. Which one of the following is most appropriate next step in management?

Assume that the same patient from the previous vignette absolutely denies any contact, sexual or otherwise, with a person who had syphilis. Also assume that both the RPR and the FTA-Abs are positive on this patient. Which of the following tests could be used to show that this patient probably does not have syphilis?

A patient is hospitalized after an automobile accident. The wounds become infected, and the patient is treated with tobramycin, carbenicillin, and clindamycin. Five days after antibiotic therapy was initiated, the patient develops severe diarrhea and pseudomembranous enterocolitis. Antibiotic-associated diarrhea and the more serious pseudomembranous enterocolitis can be caused by which of the following organisms?

A 2-year-old child has a fever, stiff neck, and is irritable. Gram stain smear of spinal fluid reveals gram-negative, small pleomorphic coccobacillary organisms. What is the most appropriate procedure to follow in order to reach an etiological diagnosis?

A patient complains to his dentist about a draining lesion in his mouth. A Gram stain of the pus shows a few gram-positive cocci, leukocytes, and many-branched gram-positive rods. Branched yellow sulfur granules are observed by a microscope. Which of the following is the most likely cause of the disease?

A 39-year-old primigravid Caucasian female lawyer develops premature rupture of membranes at 35 weeks of gestation. She develops fever up to 103°F, and the amniotic fluid reveals a group B Streptococcus. Which of the following is the best option to reduce Group B streptococcal infection in her fetus?

A 1-week-old neonate presents to the pediatric emergency room with fever, irritability, poor feeding, and a bulging anterior fontanelle. Lumbar puncture is performed, and the cerebrospinal fluid (CSF) grows group B Streptococcus. Which of the following is the most likely pathogenic mechanism?

A man who has a penile chancre appears in a hospital’s emergency service. The VDRL test is negative. Which of the following is the most appropriate course of action?

A clinically depressed farmer complains of extreme weakness, a daily rise and fall in fever, and night sweats. Small gram-negative rods are isolated from blood cultures after a 2-week incubation period. Which of the following organisms is the most likely etiologic agent?

An outbreak occurs in a community where the water supply is contaminated. Multiple patients experience nausea and vomiting as well as profuse diarrhea with abdominal cramps; stools are described as “rice water.” Curved, gram-negative rods are isolated on a sulfate-citrate bilesucrose agar. In the treatment of patients who have cholera, the use of a drug that inhibits adenyl cyclase would be expected to have which of the following characteristics?

A box of ham sandwiches with mayonnaise, prepared by a person with a boil on his neck, is left out of the refrigerator for the on-call interns. Three doctors become violently ill approximately 2 hours after eating the sandwiches. Which of the following is the most likely cause?

A 34-year-old diabetic truck driver notices maceration of the web space of his toes on the right foot. Two days later he has a temperature of up to 100°F, exquisite tenderness, erythema, and swelling of the right leg. Culture exudate from the foot yields S. aureus. Which of the following often complicates treatment of S. aureus infection with penicillin?

Two of 3 family members have dinner at a local restaurant and, within 48 hours, start experiencing double vision, difficulty in swallowing and speaking, and breathing problems. These symptoms are consistent with which of the following?

A clinical research group attempting to develop an improved Neisseria meningitidis vaccine is granted approval to gather volunteers for a clinical trial. Part of the volunteer evaluation is to sample bacteriologically for normal oral flora Neisseria. They find that almost all of the participants have several commensal species as part of their upper respiratory tract (URT) flora. Which of the following statements accurately describes the significance of these bacteria?

A family routinely consumes unpasteurized milk, claiming “better taste.” Several members experience a sudden onset of crampy abdominal pain, fever, and profuse bloody diarrhea. Campylobacter jejuni is isolated and identified from all patients. Which of the following is the treatment of choice for this type of enterocolitis?

An unimmunized, 2-year-old boy presents with drooling from the mouth, elevated temperature, and enlarged tonsils. During attempts at intubation, no gray-white membrane is observed but the epiglottis appears “beefy” red and edematous. Which of the following is the most likely organism?

A 70-year-old female patient is readmitted to a local hospital with fever and chills following cardiac surgery at a major teaching institution. A gram-positive coccus grows within 24 hours from blood taken from the patient. Initial tests indicate that this isolate is resistant to penicillin. Which of the following is the most likely identification?

Further testing of the patient in the previous question reveals that the isolate possesses the group D antigen, and is not β-lactamasepositive, but is resistant to vancomycin. Which of the following is the most likely identification of this isolate?