Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
MLS 334 exam 1
| Question | Answer |
|---|---|
| What are the 4 steps of the microbiology lab? | Obtain the specimen, plate it to media, identify what is growing, and perform antimicrobial susceptibility testing to determine what antibiotics can be used. |
| what do incubators do? | combine different temperatures and CO2 concentrations to create different environments for optimal growth. |
| what are the most common incubators? | 37C with CO2, 35C with ambient air, anaerobic jars or chambers and 30C with ambient air. |
| how are wound cultures incubated? | on BAP, CHOC and CAN media and incubated in 37C CO2, and MAC in 35C ambient |
| how are urine cultures incubated? | on BAP and MACmedia and are both incubated at 35C ambient |
| how are fungus cultures incubated? | plates are incubated in 30C ambient |
| what is assessed on 4x? | larger organisms and parasites |
| what is assessed on 10x? | the quality of the specimen |
| what is assessed on 40x? | the quantitation of WBC and RBC |
| what is assessed on 100x? | the identification and quantification of bacteria |
| when should the condenser be down? | for wet preps |
| when should the condenser be up? | gram stained and other stained specimens |
| what is a rapid biochemical test? | a test performed after the initial culture and gram stain to rapidly identify different groups of bacteria to help guide what testing should be done next. |
| what tests are included under the rapid biochemical test? | catalase, coagulase, oxidase, PYR |
| list routine media | BAP, MAC, CHOC, CAN, Thio |
| what does catalase test do? | identifies if the bacteria contains the enzyme catalase. The catalase enzyme breaks down hydrogen peroxide into oxygen and water which creates a rapid production of bubbles (positive). Used primarily to differentiate staph from strep. |
| what does the coagulase test do? | identifies if the bacteria contains the enzyme coagulase. Converts fibrinogen to fibrin and results in clot formation or clumping. differentiates staph aureus from other coagulase negative staph species. |
| what does oxidase test do? | identifies if the bacteria contains the enzyme cytochrome-C oxidase. A blue/purple compound is produced when tetramethyl-para-phenylenediamine reacts with the cytochrome-C oxidase. Differentiates nonfermenting gram negative rods. |
| what does the PYR test do? | identifies if the bacteria contains the PYR enzyme. Produces a red/ pink color to identify group A strep. |
| define taxonomy | the orderly classification and grouping of organisms |
| define classification | the arrangement of organisms into groups |
| nomenclature | assigning names to various taxonomic rankings for each microbial species |
| how is phenotype assessed? | through media, gram stains, morphology, biochemical characteristics, and antimicrobial resistance patterns |
| what are the 4 main types of pathogens that cause human disease | bacteria, fungi, viruses and parasites |
| define infection | invasion and multiplication of microorganisms within a host |
| where is normal flora found | skin, URT, GI, female genital tract |
| recall the three ways an infectious disease can be classified | microbiological (pathogens or causative agent), clinical (clinical manifestation), epidemiological (transmission, reservoir) |
| list the chain of infection | pathogen, reservoir, portal of exit, mode of transmission, portal of entry, susceptible host |
| define commensalism | microorganism benefits, host is not harmed |
| define mutalism | both microorganism and host benefit |
| define carrier | not harming host but can be passed to someone else |
| define transient microbiota | microbes that occupy the body for a short amount of time |
| define resident microbiota | microbes that have established 'residence' |
| define opportunistic pathogen | host resistance low an generally do not cause disease |
| define iatrogenic infection | infections from medical treatments or procedures |
| what are the antibacterial substances | fatty acids, lysozyme, and bile |
| what are the body sites that contain normal flora | skin and mucous membranes, upper respiratory, GI, outer opening of urethra, external genitalia, vagina, external ear and canal, external eye |
| what body sites are sterile? | internal organs and tissue, fluids within organ or tissue such as blood, urine and CSF |
| describe skin flora | skin surface and hair follicles, apocrine sweat glands. The normal flora colonzies the skin to prevent pathogens from forming. |
| list the common skin flora | candida spp., micrococcus spp., staphylococcus spp., clostridium spp., propionibacterium spp., diphtheroids |
| describe mouth flora | supports anaerobic growth with low oxidation reduction potential, buccal mucosa and tooth surface. Microorganisms produce acids which can lead to tooth decay. |
| list the common mouth flora | streptococcus mitis, streptococcus sanguis, streptococcus salivarius, streptococcus mutans |
| describe respiratory flora | lower respiratory tract normally considered sterile and ciliary epithelial cells and mucous help protect |
| list the common flora of respiratory tract | staph aureus, staph epidermidis, diphtheroids, haemophilus, streptococcus spp. |
| describe GI flora | composed of esophagus, stomach, small intestine and colon, this environment favors anaerobes. stomach usually sterile |
| is enterobacteriaceae a group of organisms? | yes |
| describe genitourinary flora | sterile: kidneys, bladder, fallopian tubes. Non-sterile: vagina and distal cm of urethra |
| define virulence | the degree or ability for a microorganism to cause disease (ability to multiply within host) |
| list microorganism virulence factors | capsules, toxins, adhesive fimbriae, and ability to survive intracellularly |
| describe the different ways a host can resist infection | physical barriers, cleaning mechanisms (tears, urine mucous, cilia), low pH, antimicrobial substances (fatty acids on skin, hydrochloric acid in stomach), indigenous microbial flora, phagocytosis, inflammation |
| list the cells involved in phagocytosis | PMNS and macrophages |
| list the steps of phagocytosis | attachment (organism to phagocyte, PMNS have various receptors, opsonization), Ingestion (surrounds attached particles, encloses in phagosome leads to degranulation), killing |
| is phagocytosis effective for intracellular pathogens? | no |
| list the mechanisms for microorganisms to resist phagocytosis | capsules, prevent fusion of phagolysosome, leukocidins, inhibit chemotaxis |
| describe innate immhnity | natural, non-specific (physical barriers, chemical barriers, phagocytosis) |
| describe adaptive immunity | acquired, specific immunity (humoral B lymphocytes, cell mediated by T lymphocytes) |
| describe IgG | 70-75%, crosses placenta |
| describe IgM | 10-15%, first antibody produced, largest |
| describe IgA | 15-20%, secreted by mucous membranes |
| describe IgD | <1%, signals B cell receptors |
| describe IgE | <1%, clearance of parasites and allergies |
| describe the primary antibody response | IgM, peak in 1-3 weeks then decline, gradually changes to IgG or IgA |
| describe the secondary response | rapid increase in IgG, IgM plays a minor role |
| what are the laboratory results associated with infection? | IgM means current or recent infection, IgG means previous infection, an elevated WBC |
| what are the components of the prokaryotic cell? | single celled, no nucleus, nor organelles, much smaller than eurokayocyte, contain a cell wall, may have capsule |
| list and describe the components in a gram positive cell wall | one major layer, peptidoglycan, surface proteins, thick, no outer membrane, narrow periplasmic space, penetrable |
| list the components of gram negative cell wall | two major layers, composed of KPS, lipoprotein, peptidoglycan, porin, proteins, thin, contains outer membrane (unique to gram negative), large periplasmic space, less penetrable to molecules |
| list the components of acid fast cell wall | waxy layer of glycolipids and fatty acids, organisms might show up lightly gram positive |
| describe the components of an absence of cell wall | plasma membrane has sterols, lack of rigid cell wall. common: genera Mycoplasma ureaplasma |
| define pleomorphic | variability in shape |
| what is the function of peptidoglycan? | to prevent osmotic lysis. A polymer that has interlocking chains of two amino sugars (NAG, NAM). |
| what is the function of lipopolysaccharides? | add strength to outer membrane |
| what is the function of surface proteins? | can function as enzymes or adhesions |
| what is the function of the gram negative cell wall? | outer membrane- semipermeable to retain certain enzymes and prevents certain toxic substances from entering |
| what is the function of periplasm? | nutrient breakdown |
| what is the function of teichoic acid | cell wall strength |
| what is the function of a capsule | the outermost layer made of polysaccharides, stick to each other and surfaces, prevents cell from drying out, protection from host immune system. |
| what environmental factors influence bacterial growth rate and what pH pathogenic bacteria grow best at? | pH, temperature, gaseous composition of atmosphere |
| what pH do pathogenic bacteria grow best at? | a neutral pH of 7.0-7.5 |
| define psychrophile | grow best at cold temperatures 10-20C |
| define mesophile | grow best at moderate temp 20-40C |
| define thermophiles | grow best at high temps 50-60C |
| define obligate aerobes | require oxygen |
| define facultative aerobes | survive in the presence of oxygen but do not use oxygen in metabolism |
| define obligate anaerobes | cannot grow in presence of oxygen |
| define facultative anaerobes | can grow with or without oxygen |
| define capnophilic | enriched with extra CO2 (5-10%) |
| define microaerophilic | reduced level of oxygen |
| what is an example of an obligate aerobe? | Pseudomonas aeruginosa |
| what is an example of an obligate anaerobe? | Clostridium spp. |
| what is an example facultative anaerobe? | Escherichia coli |
| what is an example of an Aerotolerant anaerobe? | streptococcus pyogenes |
| what is an example of a microaerophiles? | helicobacter pylori |
| what is an example of capnophile? | Haemophilus influenzae |
| describe the purpose of an anaerobic jar | to remove oxygen to get the anaerobes to grow |
| list the 4 steps in the population growth curve | lag phase, log phase, stationary phase, death phase |
| what is the clinical significance of direct examination in the lab? | make sure that material submitted is representative, identify infectious agents, identify cellular components and debris from inflammation and or infection, help guide physicians for empiric treatment, help develop epidemiologic data |
| what is the purpose of acid fast stain? | differential stain to identify acid fast organisms |
| what is the principle of the acid fast stain? | carbolfuchsin can penetrate the cell wall |
| what is the interpretation of the acid fast stain? | acid fast cells will stain fuschia and non acid fast cells will stain blue |
| what is the purpose of KOH staining procedure? | detect fungal elements in skin, hair, nails and tissue |
| what is the principle of KOH staining procedure? | KOH will break down keratin and skin for easier interpretation |
| what is the purpose of trichrome stain? | detecting intestinal protozoa from stool samples |
| what is the principle of trichrome stain? | permanent stained smear that will stain trophozoites and cysts |
| what is the purpose of calcofluor white? | detecting fungal elements in skin, hair, nails and tissues |
| what is the principle of calcofluor white? | calcofluor white will bind to polysaccharides present in fungus |
| what is the interpretation of calcofluor white stain? | fungus will fluoresce green or blue white |
| what is the purpose of giemsa stain? | staining for malarial parasites in blood smears, inclusion bodies in chlamydia, |
| what is the principle of giemsa stain? | differential stain that contains azure, methylene blue and eosin dyes |
| what is the purpose of acridine orange stain? | used to find bacteria in specimens that may be difficult (early blood cultures) |
| what is the principle of acridine orange stain? | fluorochrome dye that can stain both gram positive and gram negative cell walls. Binds to nucleic acid of cell. Needs fluorescent microscope needed. |
| what are the grading guidelines for sputum? | quantitate on 10x the squamous epithelial cells and WBC. reject sputum sample if there are >25 SEC present and any amount of WBC |
| what is spirillum? | thick spiral |
| what is spirochete? | thin spiral |
| it is not okay to report gram positive diplococci cat eyes | true |
Created by:
marynelson01