lab 13 Flashcards by Melissa Dyke

Shallow wound characteristics and 3 examples

More oxygen
More potential infections from aerobic bacteria
Staphylococcus aureus (most common pathogen)
Staphylococcus epidermidis (very common normal flora)
Streptococcus pyogenes (strep throat)

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Deep wound characteristics and 1 example

Less oxygen
More potential infections from anaerobic bacteria
Clostridium spp. (C. perfringens, obligate)

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Differentiating Gram positive staphylococcus

Staphylococcus aureus

Common wound pathogen, especially nosocomials
Colony- golden tan, medium size, entire raised, entire margin
Beta hemolytic on sheep blood agar
Coagulase positive/catalase positive
Mannitol fermentation positive
Procoagulase causes coagulates materials in the body by converting fibrin to fibrinogen

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Differentiating Gram positive staphylococcus

Staphylococcus epidermidis

Less common wound pathogen, but occasionally cause sub-acute bacterial endocarditis
On skin and URT
Colony- off white, small to medium size, raised, entire margin
Coagulase negative/catalase positive
Mannitol fermentation negative

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Clostridium sp. info

Often found in soil
Cause serious deep wound diseases such as gas gangrene
Other disease: botulism, tetanus, food poisoning
GPB with endospores
Strict anaerobe

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Testing for oxygen requirements of microbes
Thioglycollate broth
(see pics of tubes)

Contains sodium thioglycollate, a reducing agent ➝ reduces oxygen in the medium
Contains dyes showing aerobic zone (oxygen indicator)
Observe growth patterns to determine:
Obligate aerobe (need O2)
Obligate anaerobe (no O2 needed)
Facultative anaerobe (yes and no on O2)

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UTI: Collect Urine for Culturing

Cleancatch midstream?

wash area, void in toilette, stop and catch midstream portion of void
Morning specimen is best (concentrated specimen)

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UTI: Collect Urine for Culturing

Catheterization?

Tube inserted via urethra into the bladder (invasive)

Urine specimen obtained (no skin contaminants usually)

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UTI: Collect Urine for Culturing

Suprapubic?

Needle and syringe used (invasive)
Inserted just superior to the pubic bone directly into bladder; urine aspirated
Best specimen (bladder contents only)

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What is another work for bladder infection?

Cystitis

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What is the most common cause of bladder infections

Escherichia coli

GNB, facultative anaerobe, enteric organism

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What is the number of organisms/ml of urine to confirm a UTI?

100,000 organisms/ml

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General lab procedure to test urine?

Obtains urine sample
Transfer 1ul urine to NA using calibrated loop and spreads
Incubate ➝ count colonies ➝ do calculation

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Thayer Martin medium contents

Selective and enriched medium for growing Neisseria gonorrhoea
Modified blood agar called chocolate agar with addition of antibiotics ➝ antibiotics inhibit other organisms

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What disease is called Treponema pallidum?

Syphilus

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What is the gram stain for Treponema pallidum and how is it viewed?

GN spirochete but often sensitive to the Gram staining process
Silver stain or Dark field microscope is used

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What is the genus and species of Syphilis

Treponema pallidum

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How is Treponema palledum transmitted?

Contact with infective manifestation of the disease, usually during close intimate contact during vaginal, anal or oral sex
Organism penetrates through mucous membranes, wounds, or hair follicles
Trans placental transmission

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Disease process of Syphilis?

Treponema pallidum
Infection or incubation period, 2-6 weeks
Starts with Primary syphilis, if untreated may progress to Secondary, latent and Tertiary syphilis

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What is primary Syphilis?

Appearance of typically a single chancre - usually painless
Chancre forms where organism entered the body- oral, genital or anal areas
Last 3-6 weeks and disappears spontaneously

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What is Secondary Syphilis?

Organisms grows and disperses in the blood, lymph and tissues
Often appears as rash, typically on palms and soles of feet
If not treated:
25% go into latent stage, no signs or symptoms (could last for years
25% become cured
50% go into tertiary stage

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What is Tertiary Syphils

Systemic disease of internal organs, nervous system, eyes, hear, blood vessels, liver, bones and joints
Difficulty coordinating muscle movements, paralysis, numbness, gradual blindness and dementia
May cause death
May form gummas, rubbery lesions, may ulcerate

What is Congenital Tertiary Syphils?

Crosses the placenta after 3rd-4th month
Child may be: stillborn or born with active syphilis
-anemic, nasal discharge, rash, saddle back nose; or normal in appearance, lesions appear later

What is the genus and species of Gonorrhea?

Neisseria gonorrhoeae

What is Neisseria gonorrhoeae?

Gonorrhea

``` Neisseria gonorrhea Transmission? Reservoir? Treatment? Areas infected? ```

``` STD; close intimate contact humans cephalsporins only Males: eyes, urethra, throat, anus Females: eyes, urethra, throat, anus, cervix ```

Gonorrhea signs and symptoms?

CM in 1-3 days Asymptomatic carriers possible (males and females) Male (urethra, pharynx, rectum): Urethritis (green/yellow discharge- frequent urination Complications: sterility Female (30-50% asymptomatic): Cervix only; vagina is resistant (pH is to low) Symptoms similar to those of males and rectal pain Complications: arthritis, sterility and PID

Neisseria gonorrhoeae in newborns

``` Eye infection (transmitted during a vaginal delivery): called gonococcal ophthalmia Preventative treatment: silver nitrate/erythromycin eye drops ```

Diagnosis of Gonorrhea

Male: diagnosed from gram stained (intracellular GNDC) urethral discharge specimen Female: diagnosed from vaginal culture ID of organism and gram stain (intracellular GNDC)- requires BOTH because females have other Neisseria sp. (GNDC) as normal flora so Neisseria gonorrhoeae must be positively identified along with the intracellular GNDC

What plate do you grow Neisseria gonorrhoeae on?

Thayer-Marin medium because it is selective and enriched chocolate agar with antibiotics. Antibiotics inhibit other orgnisms

What is Chlamydia trachomatis?

Chlamydia STD (intracellular parasite)

How is Chlamydia transmitted?

Human to human contact during vaginal, anal or oral sex. | May also be transmitted to newborn during vag delivery

What are signs and treatment of Chlamydia?

Corneal scarring- blindness Cervix infected ➝ PID ➝ infertility Treatment: Azithromycin or doxycycline

Name 2 bacterial pathogens that cause wound infections?

Staphylococcus sp. | Clostridium sp.

Name 4 bacterial pathogens that cause urogenital infections including STD?

Escherichia coli Neisseria gonorrhoeae Treponema pallidum Chlamydia trachomatis

Members of the genus Staphylococcus are common inhabitants of the human skin. What is the Gram stain? What plate is used and why?

Gram positive cocci | MSA because they can tolerate the salt contents of the plate

What test is performed in order to differentiate Staphylycoccus and Streptococcus?

``` Catalase test (know chart in PPT) ```

What test is performed in order to diffentiate Staphylococcus aureus and Staphylococcus epidermidis?

``` Coagulase test (know chart in PPT) ```

``` What is? Central endospore Subterminal endospore Terminal endospore? Non-deforming or Deforming? ```

Central endospore is located in the middle of the vegetative cell and is non-deforming Subterminal endospore is located towards one end but not completely at the end, Non-deforming Terminal endospore is at the end, deforming

What enzyme does gonorrhea produce?

Oxidase

What is Lactobacillus sp.?

Part of the normal flora of the vagina. It produces acid products which protect the vagina from pathogens and prevents and overgrowth of Candida albicans that cause yeast infections.

Name a medium that is used to grow many fastidious organisms and why?

Thayer Martin medium (chocolate agar) because is has added antimicrobials

What is the growth pattern on NA for the following: Staphylococcus aureus Staphylococcus epidermidis Escherichia coli

Nutrient Agar Staphylococcus aureus- good growth Staphylococcus epidermidis- good growth Escherichia coli- good growth

What is the growth pattern on MSA for the following: Staphylococcus aureus Staphylococcus epidermidis Escherichia coli

Mannitol salt agar Staphylococcus aureus- good growth with yellow halo around colonies Staphylococcus epidermidis- poor growth Escherichia coli- no growth

Mannitol salt agar contents

``` Beef extract Peptone Agar Distilled/deionized water D-Mannitol Phenol red 7.5% Sodium chloride ```

Nutrient agar contents

Beef extract Peptone Agar Distilled/deoinized water

Describe the location of growth in a thioglycollate medium containing a: Strict aerobe? Strict anaerobe? Facultative anaerobe?

Strict aerobe- top of tube Strict anaerobe- bottom of tube Facultative anaerobe- through out tube

Describe the location of growth in a thioglycollate medium containing a: Strict aerobe? Strict anaerobe? Facultative anaerobe?

Strict aerobe- top of tube Strict anaerobe- bottom of tube Facultative anaerobe- through out tube

Urine colony count from incubated NA plate: | Plate count 88. Does this patient have cystitis?

NO 88 X 1000 = 88,000 org/ml 100,000 would be considered positive for cystitis

What are 2 most common newborn chlamydial infections?

Conjunctivitis and pneumonia

What are 2 most common newborn chlamydial infections?

Conjunctivitis and pneumonia

What is the treatment for Gonorrhea?

Cephalosporin

What is the treatment for Syphilis?

Benzathine penicillin G 2.4 million units for Primary, Secondary and latent. Benzathine penicillin G 7.2 million unit for late latent