Alpha & Non-hemolytic Streptococcus Flashcards by RJ A

What indicates inflammation from Strep pneumoniae?

C substance in the cell wall can elicit a C-reactive protein in the patient
Non-specific & only indicates inflammation

How well did you know this?

Not at all

Perfectly

What is Streptococcus pneumoniae referred to & what is it?

Pneumococcus

Pathogen that causes pneumocccoccal pneumonia & meningitis

How well did you know this?

Not at all

Perfectly

What is S. pneumoniae famous for?

A capsule - virulence factor

50 types

How well did you know this?

Not at all

Perfectly

What is used to serotype the bacteria S. pneumoniae?

The Neufield test

Antisera & capsule will cause a swelling in the Quellung reaction

How well did you know this?

Not at all

Perfectly

What does S. pneumoniae cause?

Pneumonia, sinusitis, otitis media, bacteremia, & meningitis
Ear infections in children over 3
Pneumonia in the elderly

How well did you know this?

Not at all

Perfectly

How does one get pneumonia & what are their risk factors?

Patient must already by colonized & not have an antibody to the strain
Immunosuppressed - alcoholism, anesthesia, viral infections
Can lead to lobar pneumonia

How well did you know this?

Not at all

Perfectly

What is effusion & pleural effusion?

Collection of serous fluid between an organ & the lining of the body cavity
Pleural effusion is effusion around the lungs

How well did you know this?

Not at all

Perfectly

What can pneumonia be accompanied by?

A pleural effusion

How well did you know this?

Not at all

Perfectly

Pneumonia can have several effusions which are?

Exudate
Transudate
Empyema

How well did you know this?

Not at all

Perfectly

What is exudate?

Effusion that is caused by infection or malignancy & has pus (WBC)
Increased LD - lactate dehydrogenase
Increased protein

How well did you know this?

Not at all

Perfectly

What is transudate?

Effusion that is caused by hydrostatic pressure
Watery
Low WBC
Low LD
Low protein

How well did you know this?

Not at all

Perfectly

What is empyema?

Collection of purulent fluid in the pleural space between the lung & chest wall
Sterile empyema has no bacteria in it
Fluid may be infected or sterile

How well did you know this?

Not at all

Perfectly

What are the characteristics of pneumococcal pneumonia, meningitis, & septicemia?

Mortality rates are high if untreated & still can be fatal if treated
Meningitis can follow otitis media & pneumonia
CSF gram stain reveals WBC & characteristic gram positive pairs - “lancet shaped pairs”
Blood cultures are positive & performed when sputum & CSF are collected
Penicillin is the drug of choice - some strains are resistant

How well did you know this?

Not at all

Perfectly

What are the types of vaccinations for pneumococcal pneumonia, meningitis, & septicemia?

PCV7

PS23

How well did you know this?

Not at all

Perfectly

What is PCV7?

Pneumococcal conjugate vaccine 7
Approved for children & part of normal pediatric care
13 valent product for children

How well did you know this?

Not at all

Perfectly

What is PS23?

23-valent vaccine used for adults

Recommended for elderly with cardiac or pulmonary disease & for asplenic individuals

How well did you know this?

Not at all

Perfectly

What are the laboratory diagnosis of Strep pneumoniae?

Specimens - sputum, blood, CSF
Sputum is cultured to BAP in CO2, MAC & CNA, & gram stained
Beta hemolytic
Colonies - umbilicate or mucoid
MAC - no growth
CNA - growth
Distinguishes from other alpha strep using optochin & bile solubility

How well did you know this?

Not at all

Perfectly

Where are the oldest colonies of S. pneumoniae?

In the center

How well did you know this?

Not at all

Perfectly

How do we differentiate green streps (what tests)?

Optochin - P disk; ethylhydrocupreine HCl
Bile solubility - sodium desoxycholate
Colony morphology
Gram stain - gram positive lancet shaped pairs & chains (capsule)

How well did you know this?

Not at all

Perfectly

What is endocarditis?

Infection of the valves of the heart
Associated with transient bacteria
Those at risk have hematologic malignancies, damaged heart valves (rheumatic fever)

How well did you know this?

Not at all

Perfectly

What are the characteristics of Viridans Streptococci?

Normal flora in the URT, female genital tract, & GI tract
Many require CO2 for growth
Are oropharyngeal normal flora which can be opportunistic pathogens
Viridans strep is the most common cause of bacterial endocarditis

How well did you know this?

Not at all

Perfectly

What does capnophilic mean?

Grows better in carbon dioxide

How well did you know this?

Not at all

Perfectly

Strep viridans is not S. pneumoniae because of?

It’s green strep without Lancefield group antigens

What are oropharyngeal commensals of Strep viridans?

Sub acute bacterial Endocarditis
Meningitis
Abscesses
Osteomyelitis
Epyema

What are the species of S. viridans?

``` Angiosus group Mitis group Mutans group Salivarius group Bovis group ```

What are the types of oral infections that are caused by S. viridans?

Gingivitis Dental caries - cavaties Oropharyngeal abscess

What are the laboratory tests for S. viridans?

All viridans are PYR positive & LAP positive | Multitest panels can be used to speciate them

What is the most commonly isolated viridans group?

S. mutans Usually from oral cavity Primary contributor to dental caries & bacteremia

What will viridans strep be seen as in cultures?

Throat culture as small green colonies in the background | Normal flora

What two types of strep bacteria are not green?

Enterococcus & group D strep

What are enterococci?

Normal flora in the intestines | Frequent causes of nosocomial infection, especially UTI, then bacteremia, & endocarditis

What are common species of enterococcus & group D strep?

E. faecalis & E. faecium

What type of lancefield antigen do enterococcus & group D strep have?

Antigen D

What type of hemolysis do enterococcus & group D strep have?

Usually hemolytic | Can be alpha or beta

What type of pseudo-catalase reaction do enterococcus & group D strep?

Weak

What type of conditions do enterococcus & group D strep grow under?

Bile High salt High temperature Alkaline conditions

What group are group D strep a part of?

Streptococcus bovis

What are the strep members of the strep bovis group?

S. equinus S. gallolyticus S. infantarius S. alactolyticus

What are the laboratory diagnosis for Enterococcus?

Urine cultures on BAP & MAC with calibrated loop to count colonies Colonies grow in CO2 but don't require it Blood cultures are their own collection media Bile esculin - positive Grow in high salt broth PYR - positive

What is esculin hydrolysis?

Ability to hydrolyze esculin Characteristic of enterococci & group D strep Some S. viridans do this

What are the two results of bile esculin?

Black - positive Growth - positive No growth - negative

What does 6.5% NaCl broth do?

Distinguishes between enterococcus & group D strep Tubes will get cloudy or stay clear No color is used for evaluation

How are enterococcus species differentiated?

Based on carbohydrate & amino acid usage Motility Ability to grow in the presence of tellurie

What are the motile forms of enterococcus?

E. faecalis - UTI E. faecium E avium E. durans

What type of enterococcus is the only one to grow in the presence of tellurite?

E. faecalis

What are the components of antimicrobial resistance to aminoglycosides?

Enterococcus is resistant to several antibiotics 6 vancomycin resistant phenotypes VanA - VanE & VanG ˜2% of E. faecalis & 60% E. faecium found in blood are vancomycin resistant - VRE

What is Van A?

Inducible | Carried on a transposon & confers a high level of resistance to vancomycin & teicoplanin

What is VanB?

Chromosomal Has variable levels of resistance to vancomycin Susceptible to teicoplanin

What are two types of nutritionally variant strep?

Abiotrophia & granulicatella spp. Not typeable by lancefield typing Growth as satellites & require SH for growth

What do nutritionally variant strep cause?

Bacteremia, endocarditis, otitis media | Very antibiotic resistant, may require surgery

What is the typical presentation of nutritionally variant strep?

``` Fever Collect blood cultures Tubes monitored under CO2 for growth Gram positive S. aureus is streaked to see if they grow in satellites around it ```

What types of nutritionally variant strep organisms are grown from supplemented media?

Pyridoxal-dependent Vitamin B6 dependent Thiol dependent Staph aureus streak plates

What are some strep like organisms?

Aerococcus Gemella Lactococcus

What is LAP leucine aminopeptidase?

Enzyme that cleaves peptide bonds, especially leucine Substrate is leucine-B-napthylamide which is hydrolyzed to B-napthylamine Red - positive PYR similar

What are characteristics of aerococcus?

``` Gram-positive cocci that form tetrads Alpha hemolytic - resemble viridans group Usually a contamininant PYR - positive Salt tolerant - 6.5% NaCl Bile esculin variable LAP - negative ```

What are lactococcus?

Similar to enterococci | Pattern of carbohydrate fermentation is used to identify & distinguish them from enterococci

What are characteristics of gemella?

Similar to viridans Decolorize easily May look gram negative cocci in pairs, tetrads, clusters or chains