lab 13 Flashcards
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)
Deep wound characteristics and 1 example
Less oxygen
More potential infections from anaerobic bacteria
Clostridium spp. (C. perfringens, obligate)
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
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
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
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)
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)
UTI: Collect Urine for Culturing
Catheterization?
Tube inserted via urethra into the bladder (invasive)
Urine specimen obtained (no skin contaminants usually)
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)
What is another work for bladder infection?
Cystitis
What is the most common cause of bladder infections
Escherichia coli
GNB, facultative anaerobe, enteric organism
What is the number of organisms/ml of urine to confirm a UTI?
100,000 organisms/ml
General lab procedure to test urine?
Obtains urine sample
Transfer 1ul urine to NA using calibrated loop and spreads
Incubate ➝ count colonies ➝ do calculation
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
What disease is called Treponema pallidum?
Syphilus
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
What is the genus and species of Syphilis
Treponema pallidum
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
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
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
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
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
