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Questions and Answers
What is the most common manifestation of GBS infections in otherwise healthy adults?
What is the most common manifestation of GBS infections in otherwise healthy adults?
- Pneumonia
- Urinary tract infections
- Peripartum fever (correct)
- Soft tissue infections
Which condition is often associated with peripartum fever?
Which condition is often associated with peripartum fever?
- Osteomyelitis
- Chronic respiratory disease
- Heart disease
- Chorioamnionitis (correct)
Which group is at greater risk for GBS infections that are not related to the peripartum period?
Which group is at greater risk for GBS infections that are not related to the peripartum period?
- Pregnant women in their third trimester
- Young adults in urban areas
- Elderly individuals and those with chronic illnesses (correct)
- Children under 5 years old
What percentage of cases report relapse or recurrence of invasive GBS infections weeks to months after the first episode?
What percentage of cases report relapse or recurrence of invasive GBS infections weeks to months after the first episode?
What is a common infection associated with Group B Streptococcal disease in adults?
What is a common infection associated with Group B Streptococcal disease in adults?
How does GBS's sensitivity to penicillin compare to GAS?
How does GBS's sensitivity to penicillin compare to GAS?
Which complication can occur occasionally from bacteremia due to GBS infection?
Which complication can occur occasionally from bacteremia due to GBS infection?
What type of infection is cellulitis considered in the context of GBS infections in adults?
What type of infection is cellulitis considered in the context of GBS infections in adults?
What hemolytic pattern is produced by streptococci that form large colonies on blood agar?
What hemolytic pattern is produced by streptococci that form large colonies on blood agar?
Which Lancefield group is associated with β-hemolytic streptococci that are commonly linked to human infections?
Which Lancefield group is associated with β-hemolytic streptococci that are commonly linked to human infections?
What is a key characteristic of α-hemolytic streptococci when cultured on blood agar?
What is a key characteristic of α-hemolytic streptococci when cultured on blood agar?
How are enterococci classified in the context of streptococci?
How are enterococci classified in the context of streptococci?
Which species of streptococci is known for causing pneumonia and meningitis?
Which species of streptococci is known for causing pneumonia and meningitis?
What characterizes streptococci with γ hemolysis?
What characterizes streptococci with γ hemolysis?
What is the role of biochemical testing in identifying certain streptococci?
What is the role of biochemical testing in identifying certain streptococci?
What association do Lancefield groups have with β-hemolytic streptococci?
What association do Lancefield groups have with β-hemolytic streptococci?
What is the recommended timeframe for screening for anogenital colonization in pregnant women?
What is the recommended timeframe for screening for anogenital colonization in pregnant women?
What is the loading dose of penicillin G recommended for intrapartum chemoprophylaxis?
What is the loading dose of penicillin G recommended for intrapartum chemoprophylaxis?
Which alternative is recommended for women with a history of penicillin allergy?
Which alternative is recommended for women with a history of penicillin allergy?
What is the primary reason Gemella morbillorum was reclassified from Streptococcus morbillorum?
What is the primary reason Gemella morbillorum was reclassified from Streptococcus morbillorum?
Under what condition should vancomycin be used for intrapartum chemoprophylaxis?
Under what condition should vancomycin be used for intrapartum chemoprophylaxis?
What percentage of pregnant women and newborns may be exposed to antibiotics due to treatment of colonization or risk factors?
What percentage of pregnant women and newborns may be exposed to antibiotics due to treatment of colonization or risk factors?
What type of infections are commonly associated with the viridans streptococci?
What type of infections are commonly associated with the viridans streptococci?
Which of the following factors is NOT a risk factor for viridans streptococcal bacteremia?
Which of the following factors is NOT a risk factor for viridans streptococcal bacteremia?
What is one potential risk associated with the treatment of colonized pregnant women?
What is one potential risk associated with the treatment of colonized pregnant women?
What is one of the main focuses of ongoing research regarding Group B Streptococcus (GBS)?
What is one of the main focuses of ongoing research regarding Group B Streptococcus (GBS)?
When does transient viridans streptococcal bacteremia typically occur?
When does transient viridans streptococcal bacteremia typically occur?
Which group of streptococci includes species that may cause various types of abscesses?
Which group of streptococci includes species that may cause various types of abscesses?
What is necessary for pregnant women who develop premature labor but have unknown culture status?
What is necessary for pregnant women who develop premature labor but have unknown culture status?
What type of infection is NOT typically associated with viridans streptococci?
What type of infection is NOT typically associated with viridans streptococci?
How do the hemolytic patterns of the S.milleri group differ from other viridans streptococci?
How do the hemolytic patterns of the S.milleri group differ from other viridans streptococci?
Which of the following statements about viridans streptococci is false?
Which of the following statements about viridans streptococci is false?
What type of infections are commonly produced by viridans streptococci?
What type of infections are commonly produced by viridans streptococci?
What is the recommended presumptive treatment for neutropenic patients with bacteremia suspected to be caused by viridans streptococci?
What is the recommended presumptive treatment for neutropenic patients with bacteremia suspected to be caused by viridans streptococci?
What must nutritionally variant streptococci require for growth in laboratory culture?
What must nutritionally variant streptococci require for growth in laboratory culture?
Which species is categorized under the genus Abiotrophia?
Which species is categorized under the genus Abiotrophia?
How does the treatment outcome of endocarditis due to nutritionally variant streptococci compare to that of usual viridans streptococci?
How does the treatment outcome of endocarditis due to nutritionally variant streptococci compare to that of usual viridans streptococci?
What two genera have nutritionally variant streptococci been reclassified into?
What two genera have nutritionally variant streptococci been reclassified into?
What is the recommended addition to the penicillin regimen for treating endocarditis caused by nutritionally variant streptococci?
What is the recommended addition to the penicillin regimen for treating endocarditis caused by nutritionally variant streptococci?
Which of the following infections is NOT commonly associated with viridans streptococci?
Which of the following infections is NOT commonly associated with viridans streptococci?
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Study Notes
Classification of Streptococci
- Streptococci are classified by hemolytic pattern, Lancefield group, species name, and trivial name.
- β-hemolytic streptococci show complete hemolysis in blood agar cultures, producing large colonies (≥0.5 mm).
- Lancefield system groups β-hemolytic streptococci into groups A, B, C, and G, each linked to specific human infections.
- α-hemolytic streptococci display partial hemolysis, resulting in a green appearance on blood agar and include Streptococcus pneumoniae and viridans streptococci.
- Nonhemolytic streptococci, referred to as γ hemolysis, include group D streptococci and enterococci.
Screening and Treatment for Group B Streptococcus (GBS)
- The CDC recommends screening for GBS colonization at 35-37 weeks of pregnancy via lower vaginal and anorectal cultures.
- Intravenous chemoprophylaxis is advised for culture-positive women or those with a history of GBS infection or bacteriuria.
- Penicillin G is the preferred chemoprophylaxis, with cefazolin as an alternative for women with penicillin allergies.
- Clindamycin is used for those with immediate hypersensitivity if susceptibility to the colonizing isolate is confirmed.
- A GBS vaccine is under development, targeting childbearing-age women to enhance maternal antibody levels in newborns.
Infections Caused by GBS in Adults
- GBS infections in healthy adults are primarily linked to pregnancy, with peripartum fever being common.
- Other infections include endometritis, chorioamnionitis, bacteremia, cellulitis, urinary tract infections, pneumonia, and septic arthritis.
- Relapses or recurrences of invasive infections occur in approximately 4% of cases.
Treatment of GBS Infections
- GBS is less sensitive to penicillin compared to Group A Streptococcus (GAS), requiring higher dosages for treatment.
Viridans Streptococci
- Viridans streptococci induce transient bacteremia, often following dental procedures or minor trauma, and are notable for their role in endocarditis.
- These organisms are often isolated in mixed flora from sites of sinusitis, brain abscesses, and liver abscesses.
- Neutropenic patients are at higher risk for viridans streptococcal bacteremia, particularly after intensive chemotherapy.
S. Milleri Group Infections
- The S. milleri group includes S. intermedius, S. anginosus, and S. constellatus, causing various suppurative infections, especially abscesses.
- These species may present with various hemolytic patterns and are associated with oral and respiratory tract infections.
Treatment Considerations for Viridans Streptococci
- Neutropenic patients with bacteremia likely require early treatment with vancomycin due to potential penicillin resistance.
- Viridans streptococci isolated in other cases reliably respond to penicillin, requiring susceptibility testing for serious infections.
Nutritionally Variant Streptococci (NVS)
- NVS, including Abiotrophia and Granulicatella species, require special growth factors for laboratory culture and are grouped with viridans streptococci.
- Endocarditis caused by NVS has a higher rate of treatment failure, often necessitating the addition of gentamicin to the treatment regimen with penicillin.
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