A 26-year-old woman visits her physician because of an unusual vaginal discharge. On examination, the physician observes a thin, homogeneous, white-gray discharge that adheres to the vaginal wall. The pH of the discharge is 5.5 (normal, <4.3). On Gram stain, many epithelial cells covered with gram-variable rods are seen. Bacterial vaginosis is diagnosed. Which one of the following normal genital flora microorganisms is greatly decreased in bacterial vaginosis?
(A) Corynebacterium species
(B) Staphylococcus epidermidis
(E) Lactobacillus species
Certain microorganisms are never considered to be members of the normal flora. They are always considered to be pathogens. Which one of the following organisms fits into that category?
(A) Streptococcus pneumoniae
(C) Mycobacterium tuberculosis
(D) Staphylococcus aureus
(E) Neisseria meningitidis
A 9-year-old girl develops fever and severe pain on the right side of her throat. On examination, redness and swelling in the right peritonsillar area are seen. A peritonsillar abscess is diagnosed. The most likely organisms to be cultured from this abscess are
(C) Corynebacterium species and Prevotella melaninogenica
(D) Normal oral nasal flora
(E) Viridans streptococci and C albicans
A 70-year-old man with a history of diverticulosis of the sigmoid colon experiences a sudden onset of severe left lower quadrant abdominal pain. Fever develops. The severe pain gradually subsides and is replaced by a constant aching pain and marked abdominal tenderness. A diagnosis of probable ruptured diverticulum is made, and the patient is taken to the operating room. The diagnosis of ruptured diverticulum is confirmed, and an abscess next to the sigmoid colon is found. The most likely bacteria to be found in the abscess are
(A) Mixed normal gastrointestinal flora
(B) Bacteroides fragilis alone
(D) Clostridium perfringens alone
(E) Enterococcus species alone
Antimicrobial therapy can decrease the amount of susceptible bowel flora and allow proliferation of relatively resistant colonic bacteria. Which one of the following species can proliferate and produce a toxin that causes diarrhea?
(C) Pseudomonas aeruginosa
(D) Clostridium difficile
Which one of the following microorganisms can be part of the normal vaginal flora and cause meningitis in newborns?
(B) Corynebacterium species
(D) Ureaplasma urealyticum
Dental plaque and periodontal disease can be thought of as a continuum of what type of physiological process?
(D) Exaggerated immune response
Which one of the following microorganisms is closely associated with dental caries?
Anaerobic bacteria such as B fragilis occur in the sigmoid colon in a concentration of about 1011/g of stool. At what concentration do facultative organisms such as E coli occur?
S pneumoniae can be part of the normal flora of 5–40% of people. At what anatomic site can it be found?
Hundreds of phylotypes have been identified in the human stomach; however, the only microorganism that has been shown to persist is
(B) Lactobacillus acidophilus
Resident flora is commonly found in the
Resident flora is absent from the
A 65-year-old woman was admitted with squamous cell carcinoma of the cervix. She underwent extensive gynecologic surgery and was maintained postoperatively on broad-spectrum intravenous antibiotics. The patient had a central venous catheter placed on the day of surgery. Beginning 3 days postoperatively, the patient became febrile. On day 8, cultures of blood and of the tip of the central line both grew gram-positive organisms that were ovoid and reproduced by budding. Which of the following microorganisms is most likely responsible for the patient’s condition?
(C) Enterococcus faecalis
(E) Saccharomyces cerevisae
A 65-year-old woman was admitted with squamous cell carcinoma of the cervix. She underwent extensive gynecologic surgery and was maintained postoperatively on broad-spectrum intravenous antibiotics. The patient had a central venous catheter placed on the day of surgery. Beginning 3 days postoperatively, the patient became febrile. On day 8, cultures of blood and of the tip of the central line both grew gram-positive organisms that were ovoid and reproduced by budding.
The most likely portal of entry for the organism in is
(A) During gynecologic surgery
(C) During placement of the central venous catheter
(D) During placement of IV line for administration of antibiotics
(E) Intubation while under anesthesia