Question | Answer |
Define opportunists. | Orgs that normally do not cause disease unless the conditions become favorable. |
Term used to describe a preliminary report sent to a physician before all testing has been completed. | Presumptive report |
What is catalase? | An enzyme produced by ALL Staphylococcus spp. |
Where can Staph epidermidis be found as a natual inhabitant of the body? | S. epidermidis is a natural inhabitant of the skin and mucous membranes |
Term given to Staphylococcus organisms that do not have the capability to produce the coagulase enzyme. | Coagulase Negative Staph (CNS) |
Which CNS is the most frequently grown in the microbiology department? | Staph epidermidis |
What do colonies of Staph saprophyticus look like on a BAP plate? | S. saprophyticus cannot be distinguished from other CNS on a BAP plate |
Define pathogen. | Organism capable of causing disease. |
What gram stain morphology does Staph aureus have? | gram positive cocci in clusters |
What three factors do Staph aureus organisms possess that contribute to their virulence? | 1. structural components of the cell wall, 2. enzymes, and 3. toxins |
True or False: Staph saprophyticus is not a CNS. | False--Staph saprophyticus IS a CNS. |
What simple laboratory test can distinguish Staph aureus from the CNS? | The coaulase test. |
What is novobiocin? | An antibiotic |
Which of the following organisms would most likely present with the following characteristics: gpc, catalase (+), coagulase (-), novobiocin resistant?
Staph aureus, Staph epidermidis, or Staph saprophyticus | Staph saprophyticus WHY: S. sapro is the only Staph spp resistant to novobiocin |
Staph species which is resistant to the antibiotic novobiocin. | Staph saprophyticus |
What is trhe gram stain reaction and morphology of the Micrococcus spp? | gpc in pairs, tetrads, clusters and/or chains |
What gram stain morphology do Micrococcus species have? | gram positive cocci in tetrads |
Staph saprophyticus can be found to inhabit what part of the human body? | the GU (genitourinary) tract of humans |
What Staph species is considered the second most common cause of UTIs (urinary tract infections) in women? | Staph saprophyticus |
What is beta hemolysis when seen on a BAP plate? | Complete hemolysis of the RBCs in the BAP media. |
A wound culture grows out a gpc with the following characteristics: Beta-hemolytic colonies on a BAP that are both catalase (+) and coagulase (+). What is the MOST likely organism? | Staph aureus |
Staph epidermidis is associated with all of the following except:
wound infections, bacteremias, nosocomial urinary tract infections, or toxic shock syndrome | toxic shock syndrome--S. aureus is associated with this type of infection |
Define saprophytic. | Saprophytic means surviving on decaying matter |
All of the following may be used to identify Staph epidermidis except:
catalase reaction, coagulase reaction, gram stain morphology, B-lactamase reaction | B-lactamase reaction. WHY: S. epi cannot produce the enzyme B-lactamase. |
What enzyme produced by certain strains of Staph aureus can cleave (breakdown) the structure of penicillin and render it useless as an effective antiobiotic? | The beta-lactamase enyzyme |
Describe what Staph epidermidis organisms look like on a BAP plate. | Colonies are small/medium, non-hemolytic, smooth/round, and white |
What is coagulase? | An enzyme that can clot or coagulate plasma. |
True or False: Staph saprophyticus is a CNS. | True |
In what areas of the body do Staph organisms normally inhabit? | Normally Staph spp. inhabit the skin and mucous membranes |
Where can Micrococci spp. be found as inhabitants? | Skin and environment |
Describe what colonies of Staph aureus look like on a BAP plate. | medium/large, smooth, round, white to creamy colored colonies. beta hemolytic |
Name three infections caused by toxins produced by Staph aurues organisms. | 1. Toxic Shock Syndrome, 2. Scalded Skin Syndrome, and 3. Food poisoning |
Staphylococcal food poisoning is characterized by:
A.rapid onset--within 2-6 hours of ingestion of enterotoxin, B.colonization of the GI tract by the bacterium,C. a 2day-2 week incubation period,D. diarrhea, but no vomiting | C. a 2 day - 2 week incubtion period |
Define pyogenic. | pus producing |
What do colonies of Micrococci spp. look like on a BAP plate? | Often pigmented, ranging in color from beige to bright yellow or orange. |
Term used to describe a final report sent to a physician when all necessary testing has been completed. | Definitive report |
A positive blood culture shows gram positive cocci in tetrads. The following day, yellow pigmented colonies are observed on a BAP plate. The colonies test catalase (+). What is the MOST likely organism? | Micrococcus spp. |