Microbiology Lecture 2 Review Qs PDF

SCIE 3672 Review Questions for Lecture 2 ======================================== 1. Sequence of events for microbial samples: 1. Collect sample 2. ***[Gram Stain ]*** 3. Inoculate culture media 4. Incubate for [ ***18-24***] hours at [***37***] ° C 5. Check f...

SCIE 3672 Review Questions for Lecture 2 ======================================== 1. Sequence of events for microbial samples: 1. Collect sample 2. ***[Gram Stain ]*** 3. Inoculate culture media 4. Incubate for [ ***18-24***] hours at [***37***] ° C 5. Check for growth: 2. Bacteriological media: 6. Agar -- a semisolid medium 7. Broth -- a [***Liquid***] medium 8. Plate -- a flat round container of agar 9. Tube -- A screw-top container -- may contain agar or broth 10. Slant -- is ***[Tube of agar that has ben allow to solod on a slant ]*** 11. What are selective media and provide 4 examples. ***Contain Compound that inhibits growth type of organism , selects certain bacteria*** Gram positive or Gram Negative Example : MacConkey II Agar ( Mac) Bismuth Sulfite Agar Eosin Methylene Blue Columbia Colistin -- nalidixic acid agar ( CNA ) Mannitol Salt Agar 12. What are differential media and provide 3 examples. ***Difference Between certain type of bacteria based on biochemical reaction*** Example : MacConkey II Agar ( Mac ) Salmonella-Shigella agar (SS) Mannitol Salt Agar Mueller-Hinton agar (MH) 13. Name two examples of nutritive media ***Growth all bacteria and some fungi*** Eg: Blood Agar Trypticase soy agar ( TSA) Detail : ***Enrich : Addition of blood , serum or eggs*** ***Enrichment : medium that favour the growth of group of bacteria*** 14. What is hemolysis and what are the different types seen on blood agar? - Differentiates between [***Lactose***] fermenters (LFs) and ***non [Lactose]*** [ ] fermenters (NLFs); a neutral red indicator stains LF colonies purple. - This agar inhibits overgrowth of [***E.coli vs Klebsiella***] spp. Eosin Methylene Blue ==================== - Dyes inhibit growth of Gram [***+***] bacteria - Selects for Gram ***-*** bacteria - Differentiates between ***Lactose*** fermenters and ***non [Lactose]*** [ ] fermenters.  Columbia colistin-nalidixic acid agar (CNA) with [ 5 %] sheep's blood ================================================================================= - Colistin and nalidixic acid [***Inhibit***] for Gram [***-***] organisms Mannitol Salt Agar ================== - 7.5% sodium chloride which ***[Select]*** for organisms that are halotolerant - An example is ***Staphylococcus spp***. - Mannitol and phenol red (pH indicator) ***Differentiate*** between organisms which can ferment [***Mannitol***] and those that cannot.  Lower Ph , cause phenol red indicator to turn Yellow Mueller-Hinton agar (MH) ======================== - General-use medium specifically formulated to give standardized results during antibiotic sensitivity testing - Used in the [***Kirby Bauer***] test - Can be enriched with ***Blood*** for more fastidious organisms - Measure diameter of each zone and compare it to zone size chart for resistance, intermediate, and susceptible. ============================================================================================================== - Selects for pathogenic enteric Gram ***-*** bacteria - Differentiates colonies on the basis of ***[Lactose]*** fermentation (pink) - Differentiates [Hydrogen Sulfide] (H2S)-producing bacteria by use of ferric citrate in the formula (black pigment seen in H2S-producing colonies).  15. Name a genus of Gram-negative bacteria that ferments lactose ***Escherichia coli*** 16. Name a genus of Gram-negative bacteria that is a non-lactose fermenter but produces hydrogen sulfide. 17. Name a genus of Gram-negative bacteria that is a non-lactose fermeneter and does not produce hydrogen sulfide. ***Shigella*** - Trypticase soy broth (TSB) - Brain-heart infusion (BHI) broth - Thioglycolate broth (THIO) - Gram-negative broth (GN) - Urea agar slant (UREA) - Bile esculin agar (BE) - Nutrient agar slant (NA) - Simmon's citrate tubes - Triple sugar iron agar - Oxidation fermentation medium with dextrose (OF) - Sodium chloride 0.85% (NaCl 0.85%) - Motility test medium 18. Name two broths for general purpose use? ***Trypticase soy broth ( TSB )*** ***Brain heart infusion (BHI)*** 19. Which broth is used for bringing bacteria to a certain turbidity level for diffusion antibiotic sensitivity testing (Kirby-Bauer)? ***Brain heart infusion (BHI)*** 20. Which broth is used in fecal culturing and is an enrichment medium for growing Salmonella spp. And Shigella spp.? ***Culture media - Tubes of broth or agar*** 21. Urea broth or agar slant (UREA) =============================== - Determines whether bacteria produce the enzyme ***[Ureas] ,*** which degrades [***Urea***] into ammonia, water, and carbon dioxide. 22. Bile esculin agar (BE) ====================== - Identifies bacteria that hydrolyze [ ***Esculin*** ](enterococci). A positive reaction turns the agar ***dark brown*** to ***Black*** 23. The colour of **Simmons Citrate agar** is ***Gream Negative*** and a positive reaction turns the colour of the agar [***Deep Blue*** ] 24. **Triple sugar agar** determines whether bacteria ferment 3 types ***of [Sugar : Glucose , lactose and sucrose].*** 25. **Sodium chloride 0.85% (NaCl 0.85%)** is a sterile solution used for diluting ***Gram Negative*** bacteria for API 20E testing. 3. Basic tests for identification of bacteria 1. How is the catalase test done and name one common genus of catalase positive bacteria and one negative genus? ***Look for production ( enzyme ) by bacteria*** ***Stick - used to smear small amount of colony - slide*** ***Drop 3% hydrogen peroxide on specimen*** ***Bubbing = Positive*** ***Staphylococcus - positive*** ***Streptococcus - negative*** 2. What indicates that the catalase test is positive? ***Bubbing or bubble*** 3. How is the coagulase test carried out and what is the main purpose of this test? ***Differentiates Staphylococcus spp*** ***Identify present of enzyme coagulase - which produce staphylococcus aures and caused blood plasma clot*** 4. What indicates that the coagulase test is positive? ***Plasma Gel*** ***Plasma Liquid - negative*** 5. In the Kirby-Bauer test, antibiotic discs - Must be kept at [***4***] °C (i.e. refrigerator) - Must not be ***Expire*** [ ] - Must be monitored using control organisms 6. What does the term control organisms mean? ***Control organisms are standard strains used to ensure the accuracy and reliability of lab tests*** 7. The optochin sensitivity test is used to test for ***Streptococcus [ ] (***genus) 8. The oxidase test determines whether bacteria produce the enzyme ***cytochrome oxidase*** [ ]. What colour indicates that the bacteria being tested\ produce ***cytochrome oxidase*** in a standard oxidase test?\ A. Yellow\ B. Pink\ ***C. Blue***\ D. Green\ Question 9. The CAMP test tests for [S***treptococcus*** ](genus) [***Agalactiae***] (species). Cause \-- Mastitis 1. What are somatic cells and why do they increase in the milk of lactating ruminants? ***Somatic cells are body cells, excluding reproductive cells.*** ***They increase in the milk of lactating ruminants due to an immune response to infections like mastitis.*** 2. What is the name of the "cowside" test for mastitis in lactating ruminants? **California Mastitis Test (CMT)**. 3. The CMT is based on gel formation when the test reagent reacts with [***DNA***] in somatic cells in the milk sample 4. Name four common mastitis pathogens ***Staphylococcus aureus\ Streptococcus agalactiae\ Streptococcus uberis*** ***Escherichia col*** 5. When a milk sample tests positive in the CMT, what is the next step in a diagnosis? ***if CMT is positive, then perform milk culture\ BAP and MAC or selective mastitis medium\ (SELMA)\ Culture milk samples (for subculture)\ Confi rmatory testing***