Streptococcus pneumoniae

For us children younger than 5 who get pneumococcal disease

1 in10 develop meningitis 1 in 20 develop pneumonia 1 in 100 develop bloodstream infection

What is the doubling time of S. pneumoniae

20-30 minutes

PPSC23 vaccine

23 valent pneumococcal polysaccharide vaccine Licensed in 1983 contains the capsular antigen of 23 of the most common disease causing serotypes covers 80-90% of serotypes that may cause invasive pneumococcal infections Primarly for adults 65 and older, younger adults who are smokers have diabetes heart disease lung cancer or HIV Effective in preventing invasive pneumococcal disease in adults but decreases over time post vaccination Efficacy of vaccine:56-86% less than 50% of patients experience mild local reactions that last less than 48hrs Limitations in pediatric population many of the serotypes are poorly immunogenic in infants and children <2

How many cases of S. Pneumoniae do you see yearly

4 out of 10 children develop it yearly

Who is at highest risk to develop pneumococcal disease

65 years and older and <2 years old

Cases of pneumococcal pneumonia

90,000 yearly cases 400,000 hospitalizations yearly 5-7% (20-28,000 patients) will die!!

Steptococcal pneumoniae

AKA-- Pneumococcus : causes pneumococcal pneumonia

Carriers of pneumococci

Adults without children 5-10% School aged children 20-60%

Lobar pneumonia

All of a single lobe of the lungs can involve more than one lobe Entire area of involvement becomes a large mass more prone to occur in younger adults 80% of cases are due to S. pneumoniae

Bronchial pneumonia

Alveoli attached to surrounding the larger bronchioles

Pros to vaccinations

Amount of pneumococcal disease cases REDUCED Reduction in transmission Reduction in carriers Overall reduction of antibiotic resistance Icreases in retention of antibiotic effectiveness ---Forms of a licensed pneumococcal vaccine in the US

Pathogenesis of S. pneumoniae

Bacteria enters lower respiratory tract and migrate into alveoli adherence to alveolar epithelium (pili and choline- binding protiens) + replication +initiation of host immune system= Lobar pneumonia release of pneumolysin and hydrogen peroxide causes disruption in alveolar epithelium edema fluid and pus accumulate in alveolar space

Hyaluronidase

Breaks down hyaluronic acid --aids in SPREAD and COLONIZATION --increases pulmonary infection

Who does Pneumococcal pneumonia typically infect

Children 5 years and YOUNGER (particularly <2) Adults 65 years and OLDER

Signs and symptoms of S. pneumoniae

Clinical presentation is BROAD and range from: --Mild (non specific) : managed as outpatient --Severe(respiratory distress) : requires ventilation All symptoms do not have to be present to have pneumococcal pneumoniae: Fever Productive cough Alveoli fill with fluid/pus causing cough shortness of breath sweating shaking/ chills headache muscle pain fatigue chest pain with breathing

How long is a patient contagious

Communicability: transmission can occur as long as organism appears in respiratory secretions, regardless of treatment. Unknown amount of time.....

What are factors that contribute to transmission of S. pneumoniae

Crowding Season of the year( winter/spring) presence of upper respiratory infections of pneumococcal disease (pneumonia/meningitis)

Pneumonia

Disease of the lung caused by a VARIETY of bacteria (streptococcus, staphylococcus, psudomonas) variety of viruses, fungi and protozoans

What are the oxygen requirements

Fermentative aerotolerant anaerobe Uses fermentation for ATP (no o2 needed)

Gram stain of S. Pneumoniae

G+ diplococci

Diagnosis of S. pneumoniae

If invasive pneumococcal disease (meningitis/bacteremia) -sample of cerebrospinal fluid/blood sent to lab for testing in non invasive pneumococcal pneumonia in adults: urine test If non invasive pneumococcal infections (ear/sinus): diagnosed based on history and physical exam

Shape of S. pneumoniae

Lancet shape

Why is it a significant problem for children and elderly

Leading cause of invasive bacterial disease

Pilli

Mediates Adhesion influences the inflammatory response through cytokine production 2nd type of pillus identified thought to be involved in adherence to epithelial cells Not all pneumococci have pili but some strains express both types

Where do you find S. Pneumoniae

Member of normal Pharyngeal flora in children and adults

Where can pneumococci be found?

Members of normal flora of respiratory tract can be isolated from 5-90% of healthy people

PLY

Most widely studied virulence factor --Belongs to hemolysin family (pore forming toxins) --Binds to cholesterol then forms large pores --mediates activation of classical complement pathway induces proinflammatory response

Does it produce a spore and or a capsule

Non Sporing Yes it has a capsule

Motility

Non motile

What are the 2 types of US licensed S. pneumoniae vaccines

PPSC23 vaccine PCV13 vaccine

What diseases can S. Pneumoniae cause?

Pneumonia Sinusitis Meningitis Otitis media Septic arthritis Endocarditis Peritonitis Cellulitis Brain abscess

What are the five virulence factors of S. pneumoniae

Polysaccharide capsule PLY Hyaluronidase Pilli Choline

Pneumolysin

Pore forming cytotoxin that activates the classical complement pathway Lysis host cells

Polysaccharide capsule

Primary virulence factor of Streptococcus pneumoniae Composed of peptidoglycan and teichoic acid --transparent: dominates in the nasopharynx and expresses less capsule --Opaque: dominates in the blood, and is characterized by and increased polysaccharide capsule-more invasive for lungs and brain Antiphagocytic Prevents C3b binding(eat me sign), inhibiting complement system activation

PCV13 vacccine

Protein Conjugate vaccines Most important serotypes are coupled to T-cell dependent antigens= stimulate a helper T-cell response (immunological memory) Licensed in 2000 13 Valent pneumococcal conjugate vaccine contains serotypes that account for 92% of serotypes that cause invasive pneumococcal disease in children <5 years old Dosage: 0-5 years (4 doses) 6-18 (1 dose) 19years + with certain conditions: (1 dose) Duration of protection Full antibody response: within 2-3weeks Antibody levels remain elevated at least 5 years Levels back to preimmunization levels 10 years Some patients may need to be REVACCIANTED if at high risk for developing pneumococcal infections

Pneumococcal surface protein A

PspA Inhibits complement system activation Binds to lactoferrin (which plays an important role in innate immunity)

Classification of S. pneumoniae

Rebecca Lansefield: Cannot be classified --Alpha hemolytic streptococcus

Choline binding proteins

Specific to S. Pneumoniae Lyt A: breaks down peptidoglycan -releases PLY from the cytoplasm LytB, LytC and CbpE--- involved in nasopharyngeal colonization

Treatment of S. pneumoniae

Standard treatment: Penicillin Invasive pneumococcal infections: broad spectrum antibiotics until antibiotic sensitivity testing results are received narrow spectrum targeted antibiotic selected based on sensitivity results symptoms typically go away 12-36 hours post antibiotic therapy vaccine has decreased antibiotic resistant pneumococcal infections

Pneumococcal pneumonia

Type of pneumonia that is ONLY CAUSED by S. Pneumoniae it is the most common clinical presentation of pneumococcal disease in adults

Septicemia/Bacteremia

When S. Pneumoniae infects the BLOODSTREAM from the LUNGS occurs in 30% of patients very serious complication : can result in additional lung problems and heart problems

catalase

negative

How is S. pneumoniae transmitted

person to person via respiratory droplets and secretions -Coughing -sneezing -Saliva -Mucus

Healthy lungs are

spongy, pink sacs that are filled with pores that fill the chest cavity. They are flexible and expand