The Streptococci, Enterococci, and Related Genera | Jawetz, Melnick, & Adelberg’s Medical Microbiology, 27e | AccessMedicine

A 48-year-old alcoholic man is admitted to a hospital because of stupor. He is unkempt and homeless and lives in an encampment with other homeless people, who called the authorities when he could not be easily aroused. His temperature is 38.5°C, and his blood pressure 125/80 mm Hg. He moans when attempts are made to arouse him. He has positive Kernig and Brudzinski signs, suggesting meningeal irritation. Physical examination and chest radiography show evidence of left lower lobe lung consolidation. An endotracheal aspirate yields rust-colored sputum. Examination of a Gram-stained sputum smear shows numerous polymorphonuclear cells and numerous gram-positive lancet-shaped diplococci. On lumbar puncture, the cerebrospinal fluid is cloudy and has a white blood cell count of 570/μL with 95% polymorphonuclear cells; Gram stain shows numerous gram-positive diplococci. Based on this information, the likely diagnosis is

(A) Pneumonia and meningitis caused by Staphylococcus aureus

(B) Pneumonia and meningitis caused by Streptococcus pyogenes

(C) Pneumonia and meningitis caused by Streptococcus pneumoniae

(D) Pneumonia and meningitis caused by Enterococcus faecalis

(E) Pneumonia and meningitis caused by Neisseria meningitidis

A 48-year-old alcoholic man is admitted to a hospital because of stupor. He is unkempt and homeless and lives in an encampment with other homeless people, who called the authorities when he could not be easily aroused. His temperature is 38.5°C, and his blood pressure 125/80 mm Hg. He moans when attempts are made to arouse him. He has positive Kernig and Brudzinski signs, suggesting meningeal irritation. Physical examination and chest radiography show evidence of left lower lobe lung consolidation. An endotracheal aspirate yields rust-colored sputum. Examination of a Gram-stained sputum smear shows numerous polymorphonuclear cells and numerous gram-positive lancet-shaped diplococci. On lumbar puncture, the cerebrospinal fluid is cloudy and has a white blood cell count of 570/μL with 95% polymorphonuclear cells; Gram stain shows numerous gram-positive diplococci.

The patient is started on antibiotic therapy to cover many possible microorganisms. Subsequently, culture of sputum and cerebrospinal fluid yields gram-positive diplococci with a minimum inhibitory concentration to penicillin G of greater than 2 μg/mL. The drug of choice for this patient until further susceptibility testing can be done is

(A) Penicillin G

(B) Nafcillin

(C) Trimethoprim–sulfamethoxazole

(D) Gentamicin

(E) Vancomycin

A 48-year-old alcoholic man is admitted to a hospital because of stupor. He is unkempt and homeless and lives in an encampment with other homeless people, who called the authorities when he could not be easily aroused. His temperature is 38.5°C, and his blood pressure 125/80 mm Hg. He moans when attempts are made to arouse him. He has positive Kernig and Brudzinski signs, suggesting meningeal irritation. Physical examination and chest radiography show evidence of left lower lobe lung consolidation. An endotracheal aspirate yields rust-colored sputum. Examination of a Gram-stained sputum smear shows numerous polymorphonuclear cells and numerous gram-positive lancet-shaped diplococci. On lumbar puncture, the cerebrospinal fluid is cloudy and has a white blood cell count of 570/μL with 95% polymorphonuclear cells; Gram stain shows numerous gram-positive diplococci.

This infection might have been prevented by

(A) Prophylactic intramuscular benzathine penicillin every 3 weeks

(B) A 23-valent capsular polysaccharide vaccine

(C) A vaccine against serogroups A, C, Y, and W135 capsular polysaccharide

(D) A vaccine of polyribosylribitol capsular polysaccharide covalently linked to a protein

(E) Oral penicillin twice daily

A 48-year-old alcoholic man is admitted to a hospital because of stupor. He is unkempt and homeless and lives in an encampment with other homeless people, who called the authorities when he could not be easily aroused. His temperature is 38.5°C, and his blood pressure 125/80 mm Hg. He moans when attempts are made to arouse him. He has positive Kernig and Brudzinski signs, suggesting meningeal irritation. Physical examination and chest radiography show evidence of left lower lobe lung consolidation. An endotracheal aspirate yields rust-colored sputum. Examination of a Gram-stained sputum smear shows numerous polymorphonuclear cells and numerous gram-positive lancet-shaped diplococci. On lumbar puncture, the cerebrospinal fluid is cloudy and has a white blood cell count of 570/μL with 95% polymorphonuclear cells; Gram stain shows numerous gram-positive diplococci.

The pathogenesis of the organism causing the infection includes which of the following?

(A) Invasion of cells lining the alveoli and entry into the pulmonary venule circulation

(B) Resistance to phagocytosis mediated by M proteins

(C) Migration to mediastinal lymph nodes where hemorrhage occurs

(D) Lysis of the phagocytic vacuole and release into the circulation

(E) Inhibition of phagocytosis by a polysaccharide capsule

A 48-year-old alcoholic man is admitted to a hospital because of stupor. He is unkempt and homeless and lives in an encampment with other homeless people, who called the authorities when he could not be easily aroused. His temperature is 38.5°C, and his blood pressure 125/80 mm Hg. He moans when attempts are made to arouse him. He has positive Kernig and Brudzinski signs, suggesting meningeal irritation. Physical examination and chest radiography show evidence of left lower lobe lung consolidation. An endotracheal aspirate yields rust-colored sputum. Examination of a Gram-stained sputum smear shows numerous polymorphonuclear cells and numerous gram-positive lancet-shaped diplococci. On lumbar puncture, the cerebrospinal fluid is cloudy and has a white blood cell count of 570/μL with 95% polymorphonuclear cells; Gram stain shows numerous gram-positive diplococci.

A 13-valent capsular polysaccharide protein conjugate vaccine for the pathogen is recommended

(A) For children up to age 18 years and for selected adults

(B) Only on exposure to a patient with disease caused by the organism

(C) For all children ages 2–23 months plus selected older children and adults with immunocompromising conditions

(D) For children ages 24–72 months

(E) For all age groups older than age 2 months

An 8-year-old boy develops a severe sore throat. On examination, a grayish-white exudate is seen on the tonsils and pharynx. The differential diagnosis includes group A streptococcal infection, Epstein-Barr virus infection, severe adenovirus infection, and diphtheria. (Neisseria gonorrhoeae pharyngitis would also be included, but the patient has not been sexually abused.) The cause of the boy’s pharyngitis is most likely

(A) A catalase-negative gram-positive coccus that grows in chains

(B) A single-stranded positive-sense RNA virus

(C) A catalase-positive gram-positive coccus that grows in clusters

(D) A catalase-negative gram-positive bacillus

(E) A double-stranded RNA virus

An 8-year-old boy develops a severe sore throat. On examination, a grayish-white exudate is seen on the tonsils and pharynx. The differential diagnosis includes group A streptococcal infection, Epstein-Barr virus infection, severe adenovirus infection, and diphtheria. (Neisseria gonorrhoeae pharyngitis would also be included, but the patient has not been sexually abused.)

A primary mechanism responsible for the pathogenesis of the boy’s disease is

(A) A net increase in intracellular cyclic adenosine monophosphate

(B) Action of M protein

(C) Action of IgA1 protease

(D) Action of enterotoxin A

(E) Inactivation of elongation factor 2

A 40-year-old woman develops severe headache and fever. Her neurologic examination findings are normal. A brain scan shows a ring-enhancing lesion of the left hemisphere. During surgery, a brain abscess is found. Culture of the abscess fluid grows an anaerobic gram-negative bacillus (Fusobacterium nucleatum) and a catalase-negative gram-positive coccus that on Gram stain is in pairs and chains. The organism is β-hemolytic and forms very small colonies (<0.5 mm in diameter). One person thought it smelled like butterscotch. It agglutinates with group F antisera. The organism most likely is

(A) Streptococcus pyogenes (group A)

(B) Enterococcus faecalis (group D)

(C) Streptococcus agalactiae (group B)

(D) Streptococcus anginosus group

(E) Staphylococcus aureus

Important methods for classifying and speciating streptococci are

(A) Agglutination using antisera against the cell wall group-specific substance

(B) Biochemical testing

(C) Hemolytic properties (α-, β-, nonhemolytic)

(D) Capsular swelling (quellung) reaction

(E) All of the above

An 8-year-old girl develops Sydenham’s chorea (“St. Vitus dance”) with rapid uncoordinated facial tics and involuntary purposeless movements of her extremities, strongly suggestive of acute rheumatic fever. She has no other major manifestations of rheumatic fever (carditis, arthritis, subcutaneous nodules, skin rash). The patient’s throat culture is negative for Streptococcus pyogenes (group A streptococci). However, she, her brother, and her mother all had sore throats 2 months ago. A test that if positive would indicate recent S pyogenes infections is

(A) Antistreptolysin S antibody titer

(B) Polymerase chain reaction for antibodies against M protein

(C) ASO antibody titer

(D) Esculin hydrolysis

(E) Antihyaluronic acid antibody titer

All of the following statements regarding the hyaluronic acid capsule of S pyogenes are correct except

(A) It is responsible for the mucoid appearance of the colonies in vitro.

(B) It is antiphagocytic.

(C) It binds to CD44 on human epithelial cells.

(D) It is an important virulence factor.

(E) A vaccine against the capsule is currently available.

Enterococci can be distinguished from nonenterococcal group D streptococci on the basis of which of the following characteristics?

(A) γ-Hemolysis

(B) Esculin hydrolysis

(C) Growth in 6.5% NaCl

(D) Growth in the presence of bile

(E) Gram stain morphology

Which of the following statements regarding the Streptococcus bovis group is correct?

(A) They possess Lancefield group D antigen.

(B) Some strains are vancomycin resistant.

(C) Infections caused by these organisms are benign.

(D) All subspecies are PYR positive.

(E) All subspecies are β-hemolytic.

Which of the following genera requires pyridoxal for growth?

(A) Aerococcus

(B) Granulicatella

(C) Enterococcus

(D) Leuconostoc

(E) Pediococcus

Which of the following genera is typically resistant to vancomycin?

(A) Aerococcus

(B) Gemella

(C) Pediococcus

(D) Streptococcus

(E) Abiotrophia

Chapter 14: The Streptococci, Enterococci, and Related Genera

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Chapter 14: The Streptococci, Enterococci, and Related Genera

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