S1B5 - Streptococcus Flashcards
How is S. pyogenes transmitted?
S. pyogenes is transmitted human-to human via respiratory droplets, food, or direct inoculation to the skin
What are abnormal lab results of the cerebrospinal fluid of Streptococcus pneumoniae meningitis?
Lab results of S. pneumoniae meningitis are:
- bacteria in cerebrospinal fluid (CSF),
- elevated CSF protein,
- elevated PMNs, and
- low CSF glucose.
Two weeks after having a sore throat and fever, a seven-year-old boy complains of knee pain, elbow pain, and chest pain. Physical examination demonstrates a macular rash on his trunk. What bacterial factor is involved in this disease?
A) Lipopolysaccharide
B) Polysaccharide capsule
C) SpeC
D) SpeA
E) M-protein
M-protein
Answer Explanation
Rheumatic fever is mediated by antibodies against S. pyogenes’ M-protein, making it an autoimmune disease. The major JONES criteria for diagnosis of rheumatic fever are carditis, polyarthritis, chorea, erythema marginatum, and subcutaneous nodules. Carditis can present as pericarditis, which would cause chest pain. The polyarthritis can occur in up to 80% of patients and most commonly involves multiple large joints. The rash and subcutaneous nodules are rare findings, and Sydenham’s chorea occurs late in rheumatic fever.
What are some virulence factors that S. pneumoniae uses to evade the host immune system?
Streptococcus pneumoniae virulence factors are IgA protease and polysaccharide capsule (anti-phagocytic).
An elderly patient is admitted from home with a pneumonia that is productive of rusty-colored sputum. Sputum cultures grow optochin-sensitive gram-positive bacteria. Which of the following diseases is least associated with this pathogen?
A) Meningitis
B) Endocarditis
C) Sinusitis
D) Otitis media
Endocarditis
Answer Explanation
Rusty-colored sputum is classic for S. pneumoniae, especially in the setting of community-acquired pneumonia. The culture results and optochin-sensitivity make it a firm diagnosis. In addition to CAP, S. pneumoniae is also the most common bacterial cause of meningitis, otitis media, and sinusitis. Endocarditis is associated with S. viridans.
Does strep viridans have a capsule? How does this compare to strep pyogenes?
S. viridans has no capsule (differentiate from hyaluronic acid capsule of S. pyogenes, polysaccharide capsule of S. pneumoniae).
Which streptococcal species causes dental caries?
A) Streptococcus pyogenes
B) Streptococcus pneumoniae
C) Streptococcus mutans
D) Streptococcus sanguis
S. mutans causes dental caries
Describe the hemolytic pattern of Streptococcus gallolyticus (formerly Streptococcus bovis) on blood agar.
In the laboratory, Streptococcus gallolyticus grows on blood agar in small colonies that are typically non-hemolytic (variable presentation).
A bacterial organism is found to be pyrrolidonyl arylamidase (PYR) test positive, what two organisms are high on your differential?
S. pyogenes is pyrrolidonyl arylamidase (PYR) test positive, a rapid test used for the presumptive identification of S. pyogenes and Enterococci.
A 12-year-old girl is brought in by her mother, who reports dark brown urine and swelling around the daughter’s eyes. The patient may have complained about a sore throat 2 weeks prior. Which lab result would confirm the suspected diagnosis?
A) Serum negative for presence of anti-DNAse B antibodies
B) Urinalysis positive for protein and red blood cells
C) Serum BUN > 50
D) Elevated serum C3 concentration
E) Serum ASO titer > 1:330
Serum ASO titer > 1:330
Answer Explanation
The suspected diagnosis is post-streptococcal glomerulonephritis. The dark brown urine suggests hematuria, and the periorbital edema suggests loss of protein. The history of pharyngitis and patient age point toward streptococcal cause, rather than one of the many other causes of hematuria and proteinuria.
In the setting of a recent Group A strep infection, ASO titers (> 1:330), anti-DNAse B antibodies, and anti-hyaluronidase antibodies are frequently elevated. While UA will definitely show proteinuria and red cells, this confirms glomerulonephritis but not the specific entity. Serum C3 concentrations are usually decreased in the setting of PSGN.
What is the morphology, gram staining, anaerobe/aerobe, and hemolysis on blood agar of Streptococcus pyogenes?
Streptococcus pyogenes (Group A Strep, GAS) is a facultative anaerobic, β-hemolytic, gram-positive cocci.
What are the two species of Enterococci normally found in humans? Which is more common and which is more likely to be resistant to vancomycin?
E. faecalis is more common and less likely to be resistant to vancomycin, while E. faeciuM is less common and More likely to be vancomycin resistant (VRE).
Is S. pyogenes bacitracin sensitive or resistant?
S. pyogenes is bacitracin sensitive, vs. S. agalactiae which is bacitracin resistant.
What are some specific species within the Streptococcus viridans group of bacteria, and what diseases do they cause?
Streptococcus viridans is a large group of commensal (non-pathogenic) gram-positive bacteria:
- S. mutans causes dental caries;
- S. sanguinis is the most common cause of subacute endocarditis;
- S. mitis can also cause bacterial endocarditis.
In what setting would you expect an Enterococci species infection?
Enterococci species are one of the leading causes of nosocomial infections in the U.S. due to high resistance.
S. pyogenes infection from what body tissue often precedes rheumatic fever?
Note that rheumatic fever is generally preceded by GAS tonsillopharyngitis and NOT GAS skin infections (impetigo).
How does S. pyogenes toxic shock-like syndrome differ from S. aureus toxic shock syndrome?
In toxic shock-like syndrome (TSLS) a systemic release of exotoxin A (SpeA) from a S. pyogenes skin infection (cellulitis) can cause polyclonal activation of T cells, leading to acute fever, shock, and multi-organ failure. In addition, TSLS patients from S. pyogenes infection present with painful, pre-existing skin infections and positive blood cultures.
S. aureus toxic shock syndrome (TSS) patients do not present with painful, pre-existing skin infections or positive blood cultures.
What are 3 organisms that contain IgA protease?
Other organisms that contain IgA protease can be remembered by the mnemonic SHiN
- S. pneumoniae
- H. influenzae type B
- Neisseria
What patients should receive the pneumococcal conjugate vaccine (a.k.a Prevnar)?
The pneumococcal conjugate vaccine (Prevnar) is given to children under 5 years and adults over 65 to prevent Streptococcus pneumoniae infection.
What types of surfaces does Streptococcus gallolyticus prefer to infect once in the bloodstream?
From the blood stream, the organism prefers to attach to collagen-rich surfaces (such as valvular surfaces) via pilus-like structures.
Which virulence factor allows S. pneumoniae to colonize the nares?
A) Beta-hemolytic activity
B) Polysaccharide capsule
C) TSST-1 superantigen
D) IgA protease
E) Alpha-hemolytic activity
IgA protease
Answer Explanation
Mucosal surfaces are usually covered with IgA as a means of passive immunity. S. pneumoniae can produce IgA protease, allowing it to colonize the nares. Its polysaccharide capsule is a virulence factor that inhibits C3b opsonization. While S. pneumoniae does have alpha-hemolytic activity, this is not in itself a virulence factor. Beta-hemolytic activity is a marker of Group B streptococcus. TSST-1 superantigen is secreted by S. aureus and causes toxic shock syndrome.
How does local infection with Enterococci species normally occur?
Infection may occur when Enterococci species overgrows locally when antibiotics suppress normal flora.
What factors increase the risk of contracting S. pneumoniae in a patient?
Patients at a higher risk for contracting pneumonia include those with
- Asthma
- Viral infection
- Smoking history
- Asplenic
- Immunocompromised
Name three disease entities caused by Enterococci infections.
Patients typical present with UTIs or biliary tract infections if infection is local. Systemic infections usually manifest as subacute bacterial endocarditis (SBE).
Colonization of heart valves by Enterococci species happens after being previously affected with what disease?
In SBE, enterococci, as well as S. viridans, colonize heart valves previously damaged from rheumatic fever.
If a patient presents with Streptococcus gallolyticus bacteremia, what other diagnostic evaluations should be performed?
Patients with Streptococcus gallolyticus bacteremia should be investigated for colorectal neoplasms (colonoscopy) due to strong correlation.
What is required to make a diagnosis of rheumatic fever?
Diagnosis of rheumatic fever requires evidence of a recent GAS infection (serology from Antistreptolysin O titer or anti-DNase B titer or bacterial culture) and either two major OR one major and two minor Jones criteria.
What are the three most common causes of neonatal meningitis from 0-6 months?
The three most common causes of neonatal meningitis from 0-6 months is:
- S. agalactiae (group B)
- E. coli
- Listeria
What factors make an individual high-risk for a severe Streptococcus pneumoniae infection?
Immunocompromised, asplenic, and older patients are at higher risk for a more severe infection.
Is S. agalactiae bacitracin resistant or sensitive?
S. agalactiae is bacitracin resistant. Contrast this with S. pyogenes, which is bacitracin sensitive.
(Bacitracin is A in the picture)
What should be administered to pregnant women who test positive for Streptococcus agalactiae?
Pregnant women with positive cultures receive intrapartum penicillin prophylaxis.
A 19-year-old woman presents in severe shock. Which finding would favor Streptococcus pyogenes over Staphylococcus aureus as the source of her shock?
A) Lobar pneumonia on chest X-ray
B) A borad-based, tender cellulitis on her thorax
C) A migratory polyarthritis with associated pericardial fluid collection
D) A tampon left in place for 2 weeks
E) A chronic wound on her leg with exposed bone
A broad-based, tender cellulitis on her thorax
Answer Explanation
Both S. pyogenes and Staphylococcus aureus can cause toxic shock, a superantigen toxin–mediated disease. The classic finding in S. aureus–caused toxic shock syndrome is a retained tampon. In S. pyogenes, the shock is preceded by a very tender soft tissue infection, such as necrotizing fasciitis. Chronically exposed bone is by definition osteomyelitis, but this only rarely presents as systemic disease. Lobar pneumonia can result in bacteremia, and proceed to shock, but GAS is not associated with pneumonia. Migratory polyarthritis and carditis are two of the JONES criteria for rheumatic fever, a late sequela of strep throat, but again is not associated with shock.
“Rusty” sputum is classically associated with pneumonia caused by what pathogen?
Patients with Streptococcus pneumoniae will have red or brown sputum, classically described as “rusty.” Bacteremia may follow.
Streptococcus gallolyticus, formerly known as Streptococcus bovis, infections has a high correlation with what other diseases besides endocarditis?
Streptococcus gallolyticus infections are known to cause infective endocarditis and have an extremely high correlation with colorectal neoplasms. Other sites of infection include the urinary and biliary system.
What are the effects of streptolysin O and S in S. pyogenes?
S. pyogenes also synthesizes streptolysin O and streptolysin S, which destroys red and white blood cells.
A patient with a 3-month-long stay in the intensive care unit is treated for a urinary tract infection. Urine cultures grow gram-positive cocci in pairs with variable hemolysis. What is the likely pathogen?
A) Escherichia coli
B) Staphylococcus aureus
C) Corynebacterium
D) Enterococcus
E) Proteus mirabilus
Enterococcus
Answer Explanation
The description of the laboratory findings, a gram-positive cocci with variable hemolysis, from a nosocomial urinary tract infection a gram-positive cocci with variable hemolysis is diagnostic for enterococcus.
A systemic release of exotoxins A, B, and C from S. pyogenes causes what disease?
Systemic release of exotoxins A, B, and C, the superantigens, causes scarlet fever.
Which different infections are commonly caused by Streptococcus pneumoniae?
S. pneumoniae causes C-MOPS
- Conjunctivitis, with patients presenting with redness and discharge in one eye
- Meningitis, with patients presenting with fever, chills, headache and neck stiffness
- Otitis media, with patients presenting with ear pain
- Pneumonia (community-acquired lobar), with patients presenting with fever, chills, cough, and chest pain
- Sinusitis, with patients presenting with fever, purulent nasal discharge, and sinus tenderness
How does non-bullous impetigo present? What is the most likely causative organism, S. aureus or S. pyogenes?
Patients with skin infections from S. pyogenes may present with pustular lesions and honeycomb-like crusts known as non-bullous impetigo at the site of inoculation. S. aureus, however, is the most common cause of both non-bullous and bullous impetigo.
What are the treatment options for non-resistant species of Enterococci? For resistant species?
Treatment includes ampicillin or vancomycin/aminoglycosides (synergistic) for non-resistant species.
For VRE, treatment includes linezolid and streptogramins (quinupristin and dalfopristin).
What role does streptokinase play in the virulence of S. pyogenes?
S. pyogenes contains streptokinase, an enzyme that converts plasminogen to plasmin and results in fibrinolysis. Surface bound plasmin activity promotes systemic spread of bacterial cells through degradation of tissue barriers and through modulation of the host immune response.
What are the 2 components of the antigen in the S. pneumoniae vaccine given to infants and toddlers?
Why are both 2 components required in this population?
The antigen in the S. pneumoniae vaccine (PCV13) given to infants and toddlers is composed of a polysaccharide capsule + protein conjugate that is similar to diphtheria toxin. The protein conjugate is required because polysaccharide antigens alone are poorly antigenic in infants and toddlers.
What disease is exotoxin B (SpeB) of S. pyogenes associated with?
Exotoxin B (SpeB) is a protease precursor that becomes activated to a cysteine protease. SpeB is associated with necrotizing fasciitis.
5-10% of adults have S. pneumoniae colonization of their nares. How does this organism avoid immunoglobulins present in mucus?
IgA protease cleaves secretory IgA (present in mucus). 5-10% of adults have nares colonized with pneumococcus.
How does hyaluronidase contribute to the virulence of S. pyogenes?
S. pyogenes contains hyaluronidase that breaks down connective tissue, facilitating spread through tissues (cellulitis).
Which bacteria commonly colonizes the female vaginal tract and often causes neonatal meningitis?
S. agalactiae causes neonatal meningitis, pneumonia, and sepsis.
In diagnosing rheumatic fever, what are the major and minor JONES criteria?
Major JONES criteria include
- Joints that are affected with migratory polyarthritis
- O or carditis (think of “O” as ♥), which may include endocarditis, myocarditis, or pericarditis
- Nodules (subcutaneous) on extensor surfaces (e.g. wrist, elbow, knee)
- Erythema marginatum rash, which is described as the presence of pink rings involving the trunk and sometimes the limbs
- Sydenham chorea, a neurologic disorder consisting of abrupt, nonrhythmic involuntary movements, muscular weakness, and emotional disturbances
Minor Jones criteria include
- Fever
- Arthralgia (cannot be used as criteria if polyarthritis is evident)
- Increased serum levels of acute phase reactants (e.g. CRP, ESR)
- Prolonged PR interval on EKG
Is S. viridans alpha or beta hemolytic?
S. viridans alpha-hemolytic (like S. pneumoniae), in contrast to β-hemolytic S. pyogenes and S. agalactiae.
Which feature distinguishes Streptococcus pneumoniae from viridans streptococci?
A) S. pneumoniae grows next to optochin discs, viridans streptococci does not
B) S. pneumoniae grows on plood agar, viridans streptococci does not
C) S. pneumoniae is insoluble in bile, viridans streptococci is soluble
D) S. pneumoniae does not grow next to optochin discs, viridans streptococci does grow next to optochin discs
S. pneumoniae does not grow next to optochin discs, viridans streptococci does grow next to optochin discs.
Answer Explanation
Streptococcus pneumoniae and viridans streptococci are both gram-positive cocci that grow in chains. S. pneumoniae is optochin-sensitive, so it will not grow immediately next to optochin-impregnated discs. Viridans streptococci is optochin-insensitive, so it will grow next to optochin. Both organisms will grow on blood agar. S. pneumoniae is bile soluble, while Viridans streptococci is bile insoluble.
What is the gram stain of Streptococcus gallolyticus, formerly known as Streptococcus bovis? Is it catalase negative or positive?
Streptococcus gallolyticus (formerly S. bovis) is catalase-negative, gram-positive coccus that is considered a member of Group D Streptococcus (GDS). This species is not part of the normal flora.
What virulence factor of Streptococcus pneumoniae puts asplenic patients particularly at risk of septic infection?
The capsule of Streptococcus pneumonia makes asplenic patients (e.g. sickle cell & splenectomy pts) particularly at risk for sepsis. Prophylactic vaccination of these patients is considered standard of care.
What is the difference between erysipelas and cellulitis?
Erysipelas is a superficial S. pyogenes infection of the skin.
Cellulitis is a deeper process that extends to the subcutis.
Both are red, tender, and warm, however cellulitis has ill-defined borders.
What type of hemolysis does Streptococcus pneumoniae exhibit on blood agar? Quellung test positive or negative? Optochin sensitive or resistant? Catalase negative or positive?
On blood agar, they are alpha-hemolytic, catalase negative and optochin-susceptible. They can be detected with the positive quellung reaction.
Which of the following organisms is hippurate positive?
A) C. trachomatis
B) S. agalactiae
C) B. anthracis
D) S. aureus
S. agalactiae
Answer Explanation
Hippurate Test is to be used in the presumptive identification of Gardnerella vaginalis, Campylobacter jejuni, Listeria monocytogenes and group B streptococci, by detecting the ability of the organism to hydrolyze hippurate.
What causes the post-streptococcal glomerulonephritis seen in patients with a recent skin and pharyngeal streptococcal infections?
Post-streptococcal glomerulonephritis follows skin or pharyngeal streptococcal infections. Circulating immune complex deposition causes glomerular damage and subsequent nephritic syndrome.
What is the most common overall bacterial cause of sore throat?
S. pyogenes is the most common bacterial cause of sore throat. Patients may present with fever, malaise, sore throat or enlarged cervical lymph nodes.
How is Streptococcus pneumoniae transmitted?
S. pneumoniae is transmitted via respiratory droplets and often occurs in people predisposed to pneumonia, ear infection, and meningitis.
Where can S. pyogenes normally be found?
S. pyogenes is part of the normal flora of skin and the oropharynx.
What tests can be done to help diagnose post-streptococcal glomerulonephritis?
Diagnosis of post-streptococcal glomerulonephritis can be made with elevated titers of antistreptolysin O (ASO) or anti-DNase B.
How would Streptococcus pneumoniae otitis media be diagnosed?
Lab results of S. pneumoniae otitis media are fluid in middle ear behind tympanic membrane and bacteria in this fluid. However, usually clinical diagnosis is sufficient enough to progress towards treatment.
Where is S. agalactiae normally found?
S. agalactiae is part of the natural flora of the gastrointestinal and vagina.
Is Streptococcus viridans optochin-resistant or optochin-sensitive?
S. viridans is optochin resistant (differentiate from optochin-sensitive S. pneumoniae).
(optochin = P disk)
What is the mechanism underlying rheumatic fever?
Rheumatic fever is caused by a cross-reactivity between S. pyogenes antigens (esp. M. proteins) and self-antigens. 80% of cases are in children and present 2-3 weeks post-infection.
How does the hyaluronic acid capsule contribute to the virulence in S. pyogenes?
S. pyogenes contains a hyaluronic acid capsule that gives it antiphagocytic properties.
Where are Enterococci species normally found?
Enterococci species normally inhabit intestines, biliary tract, and genitourinary tract.
What is the morphology, gram staining, catalase positive/negative, and hemolysis on blood agar of Streptococcus agalactiae?
Streptococcus agalactiae (GBS, Group B streptococcus) is a catalase negative gram-positive cocci with beta hemolysis on blood agar.
What is the antibiotic used for S. agalactiae infections?
Treatment includes penicillin G.
Pregnant women with positive cultures receive intrapartum penicillin prophylaxis.
How does systemic infection with Enterococci species normally occur? Where does it often colonize?
Systemic infection occurs when bacteria enter bloodstream when mucosal or epithelial barrier is disrupted and often colonize heart valves.
Lancet-shaped, gram-positive bacteria are isolated from the CSF of a patient with meningitis. Which patient population is at risk for infection by this pathogen?
A) Adult patient with sickle cell disease
B) Patients who only received the heptavalent conjugate vaccine
C) Patients who only receive the 23-valent conjugate vaccine
D) Patients with nares colonized by this bacterium
E) Patients with intracranial hemorrhage
Adult patients with sickle cell disease
Answer Explanation
The question stem describes S. pneumoniae, which causes meningitis, otitis media, sinusitis, and community-acquired pneumonia. The polysaccharide capsule inhibits opsonization, and patients missing spleens (e.g. sickle cell patients or splenectomized patients) are more at risk for infection. Patients who received either the 7- or 23-valent vaccine are less at risk for infection. Colonization of nares doesn’t increase risk for meningitis, nor does intracranial bleeding.
What are manifestations of scarlet fever?
In scarlet fever there is a systemic release of pyrogenic exotoxins A, B, and C (SpeA, SpeB, and SpeC). This leads to:
- Fever
- Pharyngitis (sore throat)
- “Strawberry” tongue (may also be seen in Kawasaki disease)
- Confluent erythematous sandpaper-like (fine, blanching) rash that begins on the chest and neck and spreads outward.
- “Circumoral pallor,” where a rash spares the nasolabial triangle and chin
- “Pastia lines,” where there is an accentuation of rash in a linear pattern along skin folds
- Rash may be followed by fine desquamation (peeling) starting with the fingers in the second week
Are Enterococci species catalase negative or positive?
Enterococci species are catalase negative.
Which organism is not bile soluble, Streptococcus viridans or Streptococcus pneumoniae?
S. viridans is not bile soluble, i.e. not susceptible to lysis by bile (vs. Streptococcus pneumoniae, which is bile soluble).
What is the morphology, gram staining, anaerobe/aerobe, and hemolysis on blood agar of Enterococci species?
Enterococci species are gram-positive facultative anaerobes that form short to medium length chains with variable hemolysis on blood agar.
Resistance to which of the following antibiotics is least likely to develop in Enterococci?
A) Amikacin
B) Oxacillin
C) Gentamicin
D) Daptomycin
E) Vancomycin
Daptomycin
Answer Explanation
Enterococcus is notorious for resistance to aminoglycosides (amikacin, gentamicin) and vancomycin (VRE, or vancomycin-resistant enterococci). Enterococcus is also often resistant to oxacillin, in fact more often than it is resistant to penicillin. Daptomycin resistance remains rare.
What role does M protein play in the virulence of S. pyogenes?
S. pyogenes contains M protein, the main virulence factor that inhibits opsonization and phagocytosis by blocking complement. There are 100+ immunotypes of M protein.
What virulence factors secreted by S. pyogenes act as superantigens?
S. pyogenes synthesizes exotoxins A, B, and C that are subject to lysogenic conversion (also called Spes, scarlet fever toxins, and erythrogenic toxins) and act as superantigens.
How do Streptococcus pneumoniae appear upon gram stain and microscopy?
Gram staining will show gram-positive lancet-shaped diplococci growing in chains.
What specimens are taken to diagnose Streptococcus pneumoniae infections? What can be used to diagnosis otitis media?
Diagnosis is made with:
- sputum sample for pneumonia,
- CSF sample for meningitis, and
- visualization with an otoscope for otitis media
How is Streptococcus pneumoniae pneumonia treated?
Treatment for S. pneumoniae should include a respiratory fluoroquinolone (levofloxacin or moxifloxacin) or combination therapy with a beta-lactam plus either a macrolide or doxycycline.
A 1-day old newborn develops sepsis. Blood cultures grow gram-positive cocci in chains that are resistant to bacitracin. The most likely risk factor for this infection is colonization of which of the following?
A) Hospital bed
B) Mother’s breast ducts
C) Newborn’s central nervous system
D) Newborn’s gastrointestinal tract
E) Mother’s vagina
Mother’s vagina
Answer Explanation
Group-B strep classically causes perinatal pneumonia, meningitis, and sepsis. 25% of pregnant women have vaginal/rectal colonization, and the pathogen is passed to the neonate during birth.
What autoimmune diseases are caused by S. pyogenes?
Autoimmune diseases caused by S. pyogenes include
- Rheumatic fever (a Type II hypersensitivity reaction)
- Post-streptococcal glomerulonephritis (a Type III hypersensitivity reaction)
- Pediatric autoimmune neuropsychiatric disorder associated with group A streptococci (PANDAS) syndrome
What special growth conditions can be used to differentiate Enterococci species from nonenterococci?
Enteroccoci species grows on 6.5% NaCl (vs. Nonenterococci) and 40% bile culture media.
What is the role of M protein in Streptococcus pyogenes infections?
A) Inhibit opsonization
B) Claeve antibodies
C) Facilitate bacterial entry into cells
D) Function as a superantigen
Inhibit opsonization
Answer Explanation
M protein is the main virulence factor of S. pyogenes that functions to inhibit opsonization.
Facilitate bacterial entry into cells is incorrect because S. pyogenes is not an intracellular pathogen.
Cleave antibodies refers to IgA protease, which S. pyogenes does not contain.
SpeA and SpeC are exotoxins of the superantigen family that are secreted by S. pyogenes, not M protein.
What are the important indications for pneumococcal polysaccharide vaccine (Pneumovax) immunization against Streptococcus pneumoniae?
Immunocompromised and asplenic patients, as well as adults over 65 should be immunized with the pneumococcal polysaccharide vaccine (Pneumovax).
What are the typical manifestations of pyogenic S. pyogenes infection (i.e. not autoimmune or toxin-related manifestations)?
Pyogenic infections caused by S. pyogenes include
- pharyngitis (“strep throat”),
- non-bullous impetigo,
- erysipelas/cellulitis.
What is the CAMP test? Which two microbes are CAMP positive?
S. agalactiae, along with Listeria monocytogenes, exhibits a positive CAMP test (CAMP factor enlarges the area of hemolysis formed by beta-hemolysin from Staphylococcus aureus).
What lab tests can be used to detect recent infection with strep pyogenes?
Diagnosis of S. pyogenes pyogenic and toxin-mediated diseases can be made through throat or skin culture. Recent infections can be detected with elevated titers of antistreptolysin O (ASO) or anti-DNase B.
