B2.5 Streptococcus pneumoniae; Abiotrophia and Granulicatella Flashcards
Streptococcus pneumoniae also known as
PNEUMOCOCCUS and DIPLOCOCCUS
encapsulated, characteristically lancet-shaped which occurs singly, on pairs and short chains
contains antigen referred to as C substance which reacts with CRP
facultative anaerobe requiring an increase CO2 tension (Candle Jar)
Streptococcus pneumoniae
Streptococcus pneumoniae VIRULENCE FACTORS
- Polysaccharide Capsule
- Adherance
- Enzymes
- Pneumolysin O
- Autolysin
- C-substance
- Hemolysin
Enzymes found in Streptococcus pneumoniae
Neuraminidase
Protease
Hyaluronidase
Streptococcus pneumoniae enzyme in charge of degrading surface structures of host tissue
Neuraminidase
Streptococcus pneumoniae enzyme in charge of facilitating bacterial colonization on mucosal surfaces by eliminating Ig
Protease
oxygen-sensitive toxin found in Streptococcus pneumoniae that is cytolytic for cells
Pneumolysin O
S. pneumoniae component that facilitates the release of pneumolysin O and other toxic proteins or inflammatory substance from cells
Autolysin
component of cell wall of S. pneumoniae which is teichoic acid that reacts with CRP resulting in the activation of some nonspecific host immune response
C-substance
RELATED INFECTIONS AND DISEASES with S. pneumoniae
- Lobar Pneumonia
- Meningitis
- Otitis Media
- Endocarditis, Peritonitis, and Bacteremia
- Secondary Atypical Hemolytic Uremic Syndrome
characterized by the presence of voluminous fluid which hastens in the spread of bacteria in the lungs
sudden onset with chills, dyspnea, and cough
most common cause of bacterial pneumonia in elderly and immunocompromised individual
Lobar Pneumonia
Microscopy of sputum from patients with Lobar Pneumonia
large number of S. pneumonia cells and WBC;
absence of oropharyngeal microbiota
follows other S. pneumonia otitis media or pneumonia
most common cause of meningitis in adults
Meningitis
most common isolate in children under 3 years old with recurrent otitis
media
Otitis Media
Specimen of choice for S. pneumoniae
Sputum, Swabs, Pus, CSF and Blood
Specimen characteristic that may indicate S. pneumonia
RUST-TINGED SPUTUM
LABORATORY DIAGNOSIS of S. pneumoniae
- Gram-Stain
- Culture Medium
- Biochemical Test
- Serologic Test
Gram-Stain observations for S. pneumoniae
Gram(+) cocci in pairs = DIPLOCOCCI
cells are slightly pointed = LANCET SHAPE
Culture Medium used for S. pneumoniae
BHIA, TSA with 5% sheep’s RBC and CAP
Blood agar plate results for young colonies of S. pneumoniae
circular, glistening, dome shaped, wet, mucoid
Blood agar plate results for old colonies of S. pneumoniae
AUTOLYTIC CHANGES result in a
collapse of each colony’s center,
giving it umbilicate or doughnot
appearance, Dimple-shaped
(CHECKER or NAILHEAD COLONIES)
BAP of S. pneumoniae
Colonies incubated aerobically produce
α-hemolysis.
BAP of S. pneumoniae
Colonies incubated anaerobically produce
β-hemolysis due to
oxygen-labile PNEUMOLYSIN O
BIOCHEMICAL TEST used for S, pneumoniae
a. Optochin Susceptibility Test/ TAXO P
b. Bile Solubility Test
c. Neufeld-Quellang Reaction/ Capsular Swelling Test
d. Francis Test
e. Mouse Virulence Test
presumptive identification of S. pneumoniae
Optochin Susceptibility Test/ TAXO P
Optochin Susceptibility Test/ TAXO P utilizes what disk
Optochin (ETHYLHYDROCUPREIN HYDROCHLORIDE)
Optochin (ETHYLHYDROCUPREIN HYDROCHLORIDE) is added to what media in order to determine S. pneumoniae
surface of an SBA plate inoculated with an α-hemolytic Streptococcus
Optochin Susceptibility Test/ TAXO P positive result for S. pneumoniae
ZOI >14 mm with a 6-mm disk = SUSCEPTIBLE
ZOI >16 mm with a 10-mm disk = SUSCEPTIBLE
Test based on the presence of autocatalytic enzyme AMIDASE in S. pneumoniae
Under the influence of BILE SALT OR DETERGENT, bacteria’s cell wall lyses during cell division
Bile Solubility Test
Bile Solubility Test detects the presence of what enzyme in order to determine S. pneumoniae
AMIDASE
Bile Solubility Test Reagent used for S. pneumoniae identification
SODIUM DEOXYCHOLATE
Bile Solubility Test Result interpretation
S. pneumoniae = solution becomes CLEAR (+)
Other α-hemolytic = solution remains CLOUDY (-)
Negative control: Suspensions made in saline
most useful, specific and rapid method for the identification of S. pneumonia (+) and allows serotyping of isolates
performed by mixing on a slide loopful of emulsified sputum or CSF with a loopful of ANTICAPSULAR SERUM and METHYLENE BLUE
Neufeld-Quellang Reaction/ Capsular Swelling Test
Neufeld-Quellang Reaction/ Capsular Swelling Test (+) reaction for S. pneumoniae
capsule appears swollen due to change in refractive index which in turn due to serologic reaction (OIL IMMERSION OBJECTIVE)
SKIN TEST for determining the presence of ANTIBODIES against pneumococci
Francis Test
Based on the sensitivity of mouse to even small inoculum of pneumococci
Sputum containing pneumococci is injected intraperitoneally to a mouse which eventually dies within 16-48 hours
Heart blood of the mouse contain pure culture of pneumococci
Mouse Virulence Test
uses particle-bound antibody to enhance the visibility of the agglutination reaction between Antigen and Antibody
Coagglutination Test
Pneumococci reaction with these test
Bile Solubility Test
Inulin Fermentation Test
Capsular Swelling Test
Quinidine Test
Optochin Test
Mouse Virulence Test
Bile Solubility Test = Bile Soluble
Inulin Fermentation Test = Fermenter
Capsular Swelling Test = Swelling of Capsule
Quinidine Test = Susceptible
Optochin Test = Susceptible
Mouse Virulence Test = Mouse dies within 16-48
hours
Streptococci reaction with these test
Bile Solubility Test
Inulin Fermentation Test
Capsular Swelling Test
Quinidine Test
Optochin Test
Mouse Virulence Test
Bile Solubility Test = Insoluble
Inulin Fermentation Test = Non-fermenter
Capsular Swelling Test = No Swelling
Quinidine Test = Resistant
Optochin Test = Resistant
Mouse Virulence Test = Won’t die
SEROLOGIC TEST FOR STREPTOCOCCI
Lancefield Precipitin Test
Direct Fluorescent Antibody Test
Coagglutiantion (Phadebact)
Enzyme-linked Immunosorbent Assay (ELISA)
Latex Agglutination Test
ASO Titer for Group A Streptococcal Infection
confirmatory test wherein cell wall antigens are extracted either physically by heating or chemical or enzymatic extraction of cell
suspension grown overnight in Todd-Hewitt Broth
Lancefield Precipitin Test
formerly known as the NUTRITIONALLY VARIANT STREPTOCOCCI
Abiotrophia and Granulicatella
Abiotrophia and Granulicatella also known as
pyridoxal-dependent or vitamin B6-dependent,
thiol-dependent and symbiotic streptococci
grow as “satellite colonies” around other bacteria and require sulfhydryl compounds for growth
part of the human oral and gastrointestinal microbiota
Abiotrophia and Granulicatella
Abiotrophia and Granulicatella Related Infections
Bacteremia,
endocarditis,
otitis media,
osteomyelitis,
endophthalmitis after cataract extraction,
brain abscess,
chronic sinusitis,
septic arthritis,
meningitis,
and breast implant– associated infections
Microscopy phenotype of Abiotrophia and Granulicatella
Gram-variable and Pleomorphic forms
Abiotrophia and Granulicatella
Species
Granulicatella adiacens,
Granulicatella elegans, and
Granulicatella balaenopterae,
Abiotrophia defective, and
Abiotrophia adjacens
Biochemical Characteristics of Abiotrophia and Granulicatella
α-galactosidase
β-galactosidase
β-glucuronidase,
Hippurate hydrolysis
Arginine hydrolysis
Acid production from trehalose and starch
