Micro bio lab exam 2

Trillions of bacteria live on and in our body (many on our skin), because the bacteria are mostly harm;less and some even beneficial

These include staphylococcus aureus, staphylococcus epidermidis and staphylococcus saprophyticus.

gram positive cocci in clusters

gram positive cocci in chains

Most pathogenic of the staphylococci, normal microbiota: skin surface, upper respiratory tract, nares, axillary, groin, perineum; can colonize various epithelial and mucosal membrane. Cause a wide range of infections: superficial skin infections; would infections, deep infections: bones, joints, deep organs, lungs and respiratory. Scalded skin syndrome; toxic syndrome; food poisoning

Ubiquitous meme ER of normal microbiota and often encountered in the laboratory as a contaminant. Normal microbiota: skin and mucous membranes; distributed widely over body surface. Can cause infections in immunocompromised patients: important nosocomial pathogen, associated with in dwelling prosthetic devices—intravascular catheters, cardiac valves, joints, cerebral shunts; bacteremia; UTIs; wounds

Second most common cause of uncomplicated UTIs in women. Normal microbiota: skin and mucosa of the urogenital tract. Cause urinary tract infections: sexually active, young females, prostatitis in men, infections in sites outside of urinary tract are uncommon

Detects the presence of the enzyme catalase, which catalyzes the breakdown of hydrogen peroxide to H2O and O2. Hydrogen peroxide is toxic to cells therefore bacteria must produce enzymes responsible for breaking it down.

If its positive it bubbles and if its negative it doesn't bubble

This agar is both selective and differential medium used to detect staphylococci

It contains a high concentration of salt which allows for growth of only salt-tolerant staphylococci to grow

It contains mannitol and the pH indicator phenol red. Fermentation of mannitol by pathogenic staphylococci (S. Aureus) produces acid, which decreases he pH and causes the agar to change from red to yellow

Staphylococcus aureus: it grows and it changes the agar yellow
Staphylococcus epidermis: it grows on the agar but it doesn't turn it yellow meaning it ca not ferment mannitol

Bacteria can grow and change color to yellow (fermented mannitol), it can grow and not change color (it doesn't ferment mannitol), lastly it could not grow at all ( salt levels too high to cause any growth)

Anatomical characteristics/ mechanisms to prevent/fight in infection: nasal hairs, antibacterial enzymes, convoluted passages, cilia and mucous lining of the trachea, mucous lining of the nasal turbinates, reflexes— coughing, sneezing, swallowing, normal microbiota of nasopharynx and presence of normal microbiota

Bacteria most commonly found in the upper respiratory tract include streptococci (teeth, mucus membranes, throat). The lower respiratory tract (trachea, bronchi, and bronchioles) is virtually free of microorganisms, mainly because of the efficient cleansing action of the Ciliated epithelium which lines the tract

Causes group A streptococci infections, cause strep throat. It's never normal microbiota in any part of body—— always a pathogen. Causes infections in upper respiratory tract

Causes group b streptococci infections, significant neonatal infections— normal microbiota: female genital tract, lower GI tact, may colonize upper respiratory tract. Infections most commonly involve neonates and infants

#1 cause of community acquired bacterial pneumonia, causes infections in the upper respiratory tract

Causes group D streptococci infections, important nosocomial infections, include UTIs.

catalase positive

catalase negative

Is both enriched and differential medium and is used to detect hemolytic microorganisms

It contains iron and other nutrients from the blood that are needed by certain bacteria to grow

Because streptococcus and staphylococcus produce toxins called hemolysis that can break down RBCs causing a visual change in the media

causes partial lysis of RBCs and breakdown of hemoglobin which leads to a green color change in the agar.

causes complete lysis of RBCs and breakdown of hemoglobin which leads to a colorless clearing in the agar

an organism that does not cause hemolysis

Is a variant of blood agar plate and contains red blood cells that have been lysed (broken apart—— cocked)

Is a rapid test system used for the qualitative detection and identification of group of streptococci

Methicillin-Resistant Staphylococcus Aureus; an infectious disease caused by a pathogen that is resistant to many antibiotics