Lab Exam 2 Microbio

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After culture of bacteria, the red color of urea broth that contains phenol red indicates that urease produced by the bacteria converted urea into ____. What is the name of molecule in the blank?

Ammonia

Catalase

An enzyme produced in all cells to decompose hydrogen peroxide, a by-product of cell respiration

true or false Fermenting lowers the pH of the MSA medium turning color into pink.

False Fermenting lowers the pH of the medium turning color into yellow.

True or False Staphylococcus aureus can ferment mannitol, but Staphylococcus epidermidis can't.

True Staphylococcus aureus can ferment mannitol, but Staphylococcus epidermidis can't.

True or false Gram-positive bacteria will not form any colonies on MacConkey medium.

True Gram-positive bacteria will not form any colonies on MacConkey medium. Crystal violet and bile salt inhibit the growth of gram-positive bacteria.

True or false? Lactose-fermenting microorganisms lower the pH of McConkey Agar

True Lactose-fermenting microorganisms produce organic acids, particularly lactic acid, which lowers the pH (colorless at neutral, bright red/pink below 6.8)

True or False most of the time Staph Aureus is harmless but can be one of the serious causes of infection .

True Staphyloccocus aureus is harmless to most healthy individuals but can opportunist bacterias.

Urinalysis (Urine test

Turbidity by looking White blood cells by microscope Leukocyte esterase detection by a rapid dipstick test (leukocyte esterase is released when leukocytes die.) pH test Detecting other proteins and nitrate

Increase elimination of the medication

Using efflux pump, bacteria can remove antibiotics from their cytoplasm.

identification of pathogens

Using selective and differential media such as MacConkey Agar. • Beta-hemolysis test

MacConkey Agar (MAC)

Gram negative bacteria like it. Gram + don't like to grow on it.

Pdase test (phenylalanine deaminase test)

Gram negative test green: + yellow:- testing for the enzyme: phenylalanine deaminase (pheynylalanine deaminase deaminates the amino acid phenylalanine)

lactose negative bacteria( gram negative bateria)

Gram-negative bacterial species will still form colonies, but colonies will have a white appearance as there will be no change in pH in the absence of lactose fermentation.

significant bacteriuria."

Greater than 100,000 bacterial colonies per milliliter urine sample

_________________uses urease to produce ammonia and neutralize gastric acid in human stomach.

Helicobacter pylori

MRSA

Hospital-acquired MRSA (HA-MRSA) Community-acquired MRSA (CA-MRSA)

What does bubbling result indicate in catalase test ?

Indicates the presence of catalase

___________________binds to starch and form blue-purple colored complex.

Iodine

Selective and differential Medias

Manitol Salt Agar(MSA)) MCconkey Agar (MAC)

Fc receptor that binds to antibodies, preventing them from functioning. It binds to Fc regions of the B-cell receptor, killing them.

Protein A

urea positive bacteria

Proteus vulgaris

__________________________are also problems, especially in hospitalized patients with indwelling urinary catheters or those receiving multiple antimicrobial agents.

Pseudomonas and Acinetobacter

How to collect and store voided urine sample

Refrigerate urine samples. Add boric acid to urine samples. Boric acid inhibits bacterial growth in the sample for up to 12 hours at room temperature. Use "Clean-Catch" or "Clean-Voided" Techniques to collect voided urine samples.

S. Aureus are beta-hemolytic but __________________ and ________________ are not

S. epidermidis S. saprophyticus

_________________________ has resistence to low concentration of novobiocin

S. saprophyticus

meticillin-sensitive Staphylococcus aureus (MSSA).

S.aureus infections that are more susceptible to methicillin .

Lactose negative species

Salmonella, Proteus, Yersinia, Pseudomonas

Types of Staphylococcus

Staphylocccus aureus Staphylococcus epidermidis Staphyloccus saprophyticus

Which bacterial species turn MSA plates yellow ?

Staphyloccoccus aureus Turns MSA plates yellow because it ferments mannitol

High salt concentration blocks growth of bacteria, but members of _______________________ can grow (halotolerant bacteria).

Staphyloccocus

Gram positive bacteria:

Staphylococci, Bacillus subtilis

Major cause of nosocomial infections

Staphylococcus aureus

True or false The end products of DNA digestion are not dissolved and removed by weak acid, but the large DNA molecule does dissolve in weak acid

false The end products of DNA digestion are dissolved and removed by weak acid, but the large DNA molecule does not dissolve in weak acid

how does bacteria avoid host defenses ?

fc region on bacteium bind to fc region of antibodies

DNase

breaks down DNA

urease

breaks down urea

signs and symptoms of cystitis

burning on urination, frequency, urgency, urine discolored (pale or red ) and foul smelling Pain in area above pubic bones

Enterotoxin

can cause food poisoning

some bacteria split urea molecules in two releasing __________ and ________________

carbon dioxide ammonia

Bacterias that produce urease break down urea in the medium(phenol red+ urea medium) causing release of ammonia which increases the ph. How does that change the results

causes a change from orange pink to dark pink

TSST-1

causes toxic shock syndrome (TSS) in the users of highly absorbent tampons

decrease in uptake of medicine

changes in protein prevent reuptake of antibiotics

staphylococcus aureus produces ____ that coagulates plasma

coagulase

defense mechanisms of S.aureus

coagulase production hemolysin production catalase production

beta hemolysin streptococci cause

complete destruction of RBCs in surroundings

Kligler Iron Agar (KIA) Test

contains the carbohydrates glucose and lactose and a pH indicator that changes from red to yellow when acids are produced by fermentation of either of these simple sugars

what is the inflammation in the urinary bladder?

cystitis

tryptophanase

degrades amino acid tryptophan into pyruvic acid, ammonia ,indole

In addition to basic nutrients, ________ media contain one or more components, such as a particular carbohydrate, that can be used by some microorganisms but not by others. If the microorganism uses the component during the incubation period, a change occurs in an indicator that is also included in the medium, which results in a color change in the medium.

diferential

McConkey Agar

differentiate lactose fermenters (pink colonies) and lactose non fermenters (yellow colonies)

Hyaluronidase

digests hyaluronic that hold cells together to help infections penetrate more deeply

Staphylokinase

dissolves fibrin clots

alpha-hemolytic streptococci

does NOT lose the red blood cells, but the hemoglobin in converted to methemoglobin (partial RBC destruction)

ways Staph aureus is transmitted

during the first days of life via transmission from mother to child. after birth the hands have been identified as the main source of transmission from mother to child.

Mechanism of Acquired Resistance

enzymes inactivate antibiotics alteration of target molecules decrease in medicine uptake increase in medication elimination

Staphylococci are _____.

facultative anaerobes

true or false Bacteriuria always indicates UTI

false Bacteriuria does not always indicate UTI. factors such as container of urine , bacteria on skin , normal flora at the end of urethra can affect how sterile urine collection is

true or false Some facultative anaerobes and aerotolerant anaerobes also are catalase positive

false Some facultative anaerobes and aerotolerant anaerobes also are catalase negative

true or false Pseudomona Aeruginosa ferment all carbohydrates

false Pseudomona Aeruginosa doesn't ferment at all.

true or false Staphylococcus saprophyticus is part of normal flora

false Staphylococcus saprophyticus is not a part of normal flora

Seratia marcescens ferments

glucose sucrose

Smaller sugars such as ____________and _____________don't interact with iodine, so no color is formed.

glucose and maltose

E. coli ferments

glucose(yellow result)

Staphylococci are ___, irregular cluster like grapes.

gram-positive cocc

Virulent Factors of Staphylococcus aureus

hemolysin coagulase leukocidin hyaluronidase staphylokinase enterotoxin

staphylococcus aureus produces ___ that destroys red blood cells.

hemolysins

Kovac's reagent reacts with____________producing brilliant red color.

indole

microorganism causing cystitis

opportunistic pathogens of the fecal flora, gram-negative bacteria such as E. coli, Klebsiella, Enterobacter, Serratia, and Proteus.

acute urethral syndrome.

patients with symptoms of cystitis have low counts of the causative agent in their urine.

Deaminase of phenylalanine forms ________________ that reacts to ferric ions forming green color.

phenylpyruvic acid

hemolysins

pore-forming toxins that damage destroy red blood cells through hemolysis

Quadrant four indicates

presence of a non lactose fermenter (salmonella typhimurium )-4

pros of catheterized urine specimens

prevents contamination of sample from normal urogenital flora. So, it presents condition of urine properly.

nonfermenter

pseudomonas aeruginosa

what is the type of UTI that generally begins in your urethra or bladder and travels to and multiply in one or both of your kidney?

pyelonephritis

Which quadrants contain lactose fermenters

quadrant 1 (Enterobacto Aerogenes)and quadrant 2(E. COli) grew red/pinkish colonies

spontaneous mutations

random change in the DNA due to errors in replication that occur without a known cause Combination therapy of multiple antibiotics used;unlikely cells will simultaneously develop resistance

The presence of indole following is indicated

red pink color ( specifically Staph aureus

Which of the following has the risk of infection in urinary bladder and cystitis?

sampling catherized urine specimens

Gram negative bacteria

scherichia coli, Serratia marcescens

Low urine pH (pH < 5.0)

seen most commonly in metabolic acidosis (kidney problem). Acidic urine is also associated with the ingestion of large amount of meat.

In addition to basic nutrients, ____ media contain one or more components that suppress the growth of some microorganisms without seriously affecting the ability of others to grow.

selective

which of the following contains DNASE Serretia marcescence or S. aureus

serratia Marcenscence Clreared spot indicated no DNA is there (degaraded by DNase)

glucose fermenter , unable to ferment lactose

shigella dysenteriae

Why are women more prone to UTIs than men

shorter urethra, their vagina/urethra is closer closer to rectum making it easier for bacteria to enter the bladder

You inoculated 0.01 ml of clean-catch voided urine sample on a nutrient agar plate and incubated at 35°C overnight. Next day, the number of colonies on the plate was 1,100. This urine sample has ____ bacteriuria. What's in the blank?

significant

type of germ that about 30% of people carry in their noses

staph aureus

which of the following is the major cause of nosocomial infections?

staphylococcus aureus

most frequent inhabitant of human surfaces, including skin and mucous membranes

staphylococcus epidermidis

Normally, urine is ___________ when excreted by the kidneys and stored in the urinary bladder.

sterile

true or false DNase produced and secreted by bacteria degrades DNA in the medium making clear circle.

true DNase produced and secreted by bacteria degrades DNA in the medium making clear circle. That indicates that the bacteria is DNase-positive

true or false Iron salt and sodium thiosulfate in KIA allow identification of Hydrogen sulfide producing bacteria in the medium.(BLACK precipitation)

true Iron salt and sodium thiosulfate in KIA allow identification of Hydrogen sulfide producing bacteria in the medium.(BLACK precipitation)

true or false Rapid urease production is characteristic of Proteus species,

true Rapid urease production is characteristic of Proteus species,

true or false Enzymes bind to their specific substrates and cause chemical change in them:

true Enzymes bind to their specific substrates and cause chemical change in them

true or false Obligate anaerobes don't have catalase.

true Obligate anaerobes don't have catalase.

true or false certain bacteria can be identified by examining the presence of a certain enzyme activity.

true certain bacteria can be identified by examining the presence of a certain enzyme activity. Occasionally, different species of bacteria have different sets of enzymes

true or false penicillium discovered by Alexander Flemmings can inhibit growth of staph aureus .

true penicillium discovered by Alexander Flemmings can inhibit growth of staph aureus .

true or false staph aureus is found among the flora of healthy individuals

true staph aureus is among the flora of healthy people

Indole test examines the presence of the enzyme ____ in bacteria. What is the name of the enzyme in the blank?

tryptophanase

indole test tests for

tryptophanase(enzyme)

Bacteria of the Proteus genus such as Proteus vulgaris produce _______________

urease

staphylococcus epidermidis and staphylococcus saprophyticus don't cause serious infections because they don't produce _____ factors such as hemolysins, coagulase, leukocidin

virulence

how should females wipe genitals for urine test .

wipe between folds of genitals front to back

how should males wipe for urine tests

wipe head of penis and opening pull foreskin back if uncircumcised

Very alkaline urine

(pH > 7.0) is suggestive of infection with a urea-splitting organism, such as Proteus mirabilis.

characteristics of staphylococci

-Gram-positive cocci -Catalase positive Colony irregular grape like cluster Hardy, facultative anaerobic organism.

steps to obtain accurate urine test

1.wash hands with soap and water . 2.handle cup carefully to avoid contaminating it do not touch the inside of cup or lid 3. wash genitals 4. start urinating into the toilet , midstream move cup in to catch some urine 5pull cup away before you finish urinating half full cup 6.put lid tightly around cup . label it properly

insignificant bacteriuria

100 to 1,000 per milliliter, not more than 10,000,

Which quadrant contains a gram positive bacteria?

3. did not grow any colonies( Staph . epidermis )

factors of cystitis in women

30% of women develop cystitis at some time during their lives. Short urethra Sexual intercourse Birth control devices such as diaphragms.

pH of human urine

4.5 to 8.2 (average 6.0)

coagulase

A bacterial enzyme that causes blood plasma to clot

R plasmid

A bacterial plasmid carrying genes that confer resistance to certain antibiotics.

Clean-Catch or Clean-Voided Techniques females

All labial surfaces must be thoroughly cleansed. The sterile container must be held in such a way that it does not contact with the skin or clothing. The first steam of urine is discarded. A midstream sample is collected. Close the container tightly and wipe the container with disinfectant

Infections caused by Staphylococcus aureus include all of the following

Bacteremia /sepsis Pneumonia Endocarditis Osteomyelitis

MacConkey Agar contains

Basal nutrients plus crystal violet, bile salt, lactose, and neutral red (pH indicator)

Antibiotic-inactivating enzymes

Beta-lactamases, carbapenemases, Kanamycin degrading enzyme,

ways to culture urine specimen

Catheterized urine specimen • Voided urine specimen

catherized urine specimen

Collecting urine sample directly from bladder by inserting a sterile polyurethane catheter tube into urethra and passing it up into the bladder.

cons of urine specimen collection

Contamination of urogenital flora into urine samples You must culture or analyze the sample immediately. You must obtain and report accurate result

What inhibits the growth of Gram-positive bacteria on MacConkey Agar?

Crystal violet and bile salt inhibit the growth of gram-positive bacteria.

Membrane-Damaging Toxins

Cytotoxins that disrupt plasma membranes causing cell to lyse

______________take the amino group out of amino acids.

Deaminases

Lactose fermenters

E. coli Enterobacter Klebsiella

You cultured Escherichia coli in a phenol red glucose broth overnight. The color of phenol red changed from red to yellow. What does it mean?

E. coli fermented glucose

factors of cystitis in males

Enlarged prostate: UTIs are unusual in men until about age 50, when enlargement of the prostate gland compresses the urethra and makes it difficult for them to completely empty the bladder. Catheterization: Medical conditions may require a urinary catheter to drain the bladder. Pathogen may create a biofilm either within or on the catheter.

gram positive bacterias that cause UTIs

Enterococcus spp., Staphylococcus saprophyticus and other coagulase- negative staphylococci, and Staphylococcus aureus

which of the following is the most frequent cause of UTI?

Escherichia coli

Mannitol Salt Agar(MSA) contains

Essential nutrient plus 7.5% NaCl, Mannitol, and phenol red (pH indicator)

alterations in target molecule

Modifications in penicillin binding proteins (PBPs), changes in ribosomal RNA,

What can detect Methicillin resistant genes

PCR test latex agglutination assay

Name the chemical component in phenyl ethyl alcohol agar that inhibits the growth of Gram-negative bacteria.

Phenyl thethyl alchohol ( selective ) Inhibits growth of Gram negative

________________________has been implicated in acute urinary tract infections in young women between 16 to 25 years of age.

Staphylococcus saprophyticus

Examples of catalase positive anaerobes

Streptococcus pyogenes and Enterococcus faecalis

all the followings are Folliculitis Pimples, furuncles (boils), carbuncles, and impetigo in skin Pneumonia, pyelonephritis, osteomyelitis, meningitis, and endocarditis. Infections of the sinuses (sinusitis) and middle ear (otitis media).

Symptoms of S. aureus infection

Clean-Catch or Clean-Voided Technique for males

Thoroughly wash the glans of the penis. Discard the first stream of urine. Collect a midstream portion in a sterile container. If the outside of container has been soiled with urine, it must be wiped clean with disinfectant before being handled further

what is the purpose of indole test ?

To distinguish bacterial species by their production of indole

what is the purpose of KIA ?

To observe how a single medium can be used to determine multiple biochemical reactions of bacteria

"Any microorganism is potentially pathogenic if it enters a susceptible host." Is it true or false?

True

If the microorganism produces _______________, it digests starch in the starch agar, and Gram's iodine will not form blue-purple color.

amylase

What is the enzyme that hydrolyzes starch?

amylase

The presence of bacteria in voided urine is _________.

bacteriuria

why can some staphyloccocci grow on mannitol salt agar?

because they are halotolerant

staphylococcus aureus is

beta-hemolytic

Enzymes

biological catalysts of biochemical reactions.

The test should not be performed with organisms growing on a ________________medium because catalase is found in red blood cells.

blood containing

bascillus subtilis

is amylase positive degragres starch

Streptococcus pyogenes

is an hemolysin bacteria

Purpose of DNase test?

is to see if the bacteria has the ability to produce the DNase enzyme

Leukocidins

kill phagocytic leukocytes

KIA contains abundant of___________ , but small amount of _____________

lactose glucose

Staphylococcus epidermidis

may cause infections if they get past barriers through wounds ect may be dangerous to immunocompromised people

cons of Catheterized urine specimen

may introduce microorganisms into the bladder that could result in infection and cystitis. So, it has a risk.

Many hospital strains of S. aureus are resistant to most of the commonly used antibiotics, especially methicillin. These strains are called

methicillin- resistant S. aureus (MRSA).

3 ways people get UTIs

microorganisms in the bloodstream are deposited to kidneys from infection site producing pyelonephritis Bacteria on the outside or at the end of urethra travel to bladder causing cystitis Microorganism in the urethra are introduced in the bladder with catheters or cystoscopes

changes enzymes cause in their substrate

modification, breaking down , combine molecules together

voided urine specimen

more commonly collected for urine culture.

Genetic Transfer

movement of DNA from one bacterium to another by transformation, transduction, or conjugation

non-hemolytic streptococci

no effect on red blood cells

pros of urine specimens collection

no risk of infection


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