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.