lab 11 Flashcards
Define Beta Hemolysis
Completely lysis of RBC’s → shows as clear area around colonies
Define Alpha Hemolysis
Parial lysis/bruising of RBC’s → shows as darker colonies (green to brown) and some clearing around colonies
Define Gamma Hemolysis
No hemolysins produced → no hemolysis
Streptococcus pyogens - causes? sample collection? macro/micro characteristics?
Cause of strep throat in upper respiratory tract, other infections
Also referred to a Group A strep (GAS)
Typical throat swab
Small/medium, white, beta hemolytic colonies.
Gram positive streptococci, some diplococci present
Streptococcu pneunoniae - causes? sample collection? macro/micro characteristics?
Causes of pneumonia in lower respiratory tract (most common agent of bacterial pneumonia)
Sputum, bronchial washing
Medium, mucoid, off what, alpha hemolytic colony.
Gram positive diplococci predominantly
-lancelet shaped cells
-capsule present if capsule stained
Normal flora in oropharynx in healthy individuals
S. salivarius (++)
S. pyogenes
S. pneumonia
S. mutans
Normal flora in oropharynx in health individuals (other could include:)
Staphylococcus sp. -S. epidermidis (++) -S. aureus Neisseria sp Corynebacteria sp Candida albicans Several strict anaerobes Others
What causes pneumonia in lower respiratory tract and produce capules?
Streptococcus pneunomiae (gpdc) Klebsiella sp. (gnb)
What does Streptococcus pneunomia and Kebsiella sp cause?
Pneumonia in LRT (produce capules)
What bacteria causes a positive and negative capsule stain and present a halo
Streptococcus pneumoniae and Klebsiella pneumoniae
Characteristics of Klebsiella pneumoniae on Endo agar
Raised, slimy growth which stings into threads when drawn with a loop
Mycobactrium tuberculosis Acid Fast Stain, what does it look like?
Formation of the organisms in a serpentine cord aligned parallel with one another. These are Acid Fast Bacilli NOT Gram negative
Mycobacterium tuberculosis is the causative agent for what disease?
Tuberculosis or TB
What is Acid Fast Stain AKA
Ziehl-Neelson Stain
Why does Mycobacterium tuberculosis not stain properly?
Has atypical cell walls containing mycolic acid and different type of peptidoglycan
What does Corynebacterium diphtherae look like gram stained?
Slender bacilli with some pleomorphism, especially clubbing, with no particular arrangement. gram positive, highly pleomorphic organisms.
What is the causative agent for Corynebacterium diphtheria?
Diphtheria (LRT)
What does Corynebacterium diphtheriae smear look like on the Loeffler medium?
Stained with methylene blue and Gram iodine. Green in color with polor or beaded staining (granules). Polor region is on both ends. Beaded staining with more than one granule on cells
What does Haemophilus influenzae look like gram stained?
Gram negative pleomorphic bacilli
What is the causation of Haemophilus influenzae?
Meningitis (CNS) in young children and other diseases. Does not cause the flu
in order to identify a streptococcus species, exhibiting a beta hemolytic pattern around colonies on SBA plate which test would you perform
Strep A Quick Antigen Test and Bacitracin susceptibility if needed
Which of the following would be most easily killed by using heat?
a. GP spore forming bacteria
b. GN non spore forming bacteria
c. GN spore forming bacteria
d. GP non spore forming bacteria
Gram Negative, non spore forming bacteria
Environment that provides increased carbon dioxide and low oxygen? What organism grows best?
Candle Jar
Capnophiles
What will result if Streptococcus (strep throat) is not treated
Rheumatic fever, Glomerulonephritis or Scarlet Fever
What causes Streptococcus pyogenes?
Strep Throat
What causes Streptococcus pneumoniae?
Bacterial pneumonia. May also serve as a potential source for infection of the meninges because it can enter the blood from lungs.
What does Streptococcus pneumoniae look like?
Forms a mucoid, wet looking colony due to a polysaccharide capsule (virulence factor)
What role doe Ciliated Epithelium play in protecting the respiratory tract against pathogens?
Moves mucus with trapped organisms and debris out of the respiratory tract
What role doe normal flora play in protecting the respiratory tract against pathogens?
Colonizes areas of the body to prevent or decrease access to the area by a pathogen
What role doe Alveolar macrophages play in protecting the respiratory tract against pathogens?
Phagocytize debris and organisms that reach alveoli. This is a protective response
What role doe secretory IgA play in protecting the respiratory tract against pathogens?
Is found in the body secretions near the surface. It binds to microorganisms and prevents them from attaching and invading mucous membranes.
Example: Vibrio choleraie, Streptococcus mutans and Neisseria gonorrhoeae will not bind to the host cells in presence of secretory IgA
What the gram statement and hemolytic pattern for Streptococcus pneumoniae?
Alpha hemolytic and gram positive dilplococcus
List 5 organisms that make up the normal flora of the URT
Neisseria sp Corynebacterium sp Streptococcus sp Staphylococcus sp Bacteroides sp Candida albicans Others
Does the isolation of Neisseria sp from the pharynx necessarily mean the a person has gonorrheal pharyngitis or another disease of Neisseria sp?
Niesseria sp isolated from the pharynx could be normal flora (pathogen or non pathogen) and must be tested. All Neisseria species are gram negative diplococci. Neisseria gonorrhoeae is an intercellular pathogen and fastidious (temp, humidy sensitive)
Identify the etiologic agent of pneumococcal pneumonia. Give the gram reaction and list two virulence factors for this microorganism
Streptococcus pneumoniae
Gram positive diplococci
Capsule, streptokinase, hemolysin (alpha)
Klebsiella pneumonia - List the causation agent, how the disease is transmitted, gram reaction if applicable ( if not applicable explain why and what is used), and typical treatment.
LRT, Caused by Klebsiella pneumonia, acquired when host defenses are impaired (alcohol, malnutrition, decreased cough mechanism, decreased mucus production) Results from inhalation of infected droplets. Therapeutic agents: amikacin, tobramycin, cephalosporins (organisms usually responds slowly; high mortality rate). Gram negative bacilli
Primary atypical pneumonia (walking pneumonia) - List the causation agent, how the disease is transmitted, gram reaction if applicable ( if not applicable explain why and what is used), and typical treatment.
LRT, Caused by Mycoplasma pneumoniae through inhalation of contaminated droplets. This is a small bacterium that lacks a cell wall (cannot be Gram stained). Therapeutic agent: tetracycline or erythromycin
Psittacosis - List the causation agent, how the disease is transmitted, gram reaction if applicable ( if not applicable explain why and what is used), and typical treatment.
Caused by Chlamydia psittaci which is inhaled from contaminated airborne dust (parrot and parrot like bird feces). It can also be caused by bird bite or from another humans contaminated respiratory droplets. This organism is an obligate intercellular parasite. Therapeutic agent: tetracycline
Streptococcus pyogens- what is the gram reaction statement and hemolytic pattern?
Gram positive streptococcus, Beta hymolitic
Stretococuccus pneumoniae- what is the gram reaction statement and hemolytic pattern?
Gram positive diplococcus, Alpha hymolitic
