stool processing (prac reports)

i am disappointed at the lack of quality and thoroughness of your research for the practical report.
Many students chose the easiest pathogens. If you dont consider the unusual or different pathogens, how are you going to learn?
Insufficient research was done on the identification of each pathogen chosen. Please consult relatively new textbooks for information
In your Gram of the culture and the specimen, you need to be specific about the morphology of the pathogens. It isnt enough to say the organism is a GNB. Many organisms have very specific shapes, an the fact that you have not indicated so, proves that you havent done sufficient reading and research. It would also be a good idea to do a simple pencil drawing to show the shapes of these organisms.
The layout of the practical reports needs work. It seems as if the information is just gathered and written down with no forethought. Subheadings are important. Just as important is the specific tasks/processing done on each day. If you dont have a clear idea of what is done on which day, please either ask me or do some extra reading.
When you have chosen your pathogens, it is important to specify a species. Shigella has 4 species, and these need to be distinguished from each other. Not all species cause severe disease.
If you have written about agar/culture plates we did not learn about in micro 1, you need to indicate the use/purpose of the plate, its main ingredients, and the expected morphology of the pathogen on that plate.
There are some students who are confused about Gram reaction and culture morphology on the agar plates.

These are some of the most important points Ive picked up from your prac reports. Please ensure that these errors are not repeated in the next prac report.

possible pathogens in stools

possible pathogens:

Vibrio cholerae
Yersinia enterocolitica
Shigella dysenteriae
Salmonella typhi/paratyphi/enteriditis
Bacillus cereus
Campylobacter jejuni
Aeromonas

how to learn urine specimen processing in micro

take an A4 page
divide into 3 parts
label each part as day 1, 2 and/or 3
provide subheadings, i.e macroscopy of specimen or culture, microscopy of specimen or culture, etc
in point form fill in everything that needs to be done
draw diagram if necessary

NB!!! you must be able to explain all types of inoculations/streaking/seeding
also all uses/purposes of media/biochemical tests used
expected results in biochemical tests
common morphology of orgs on all media used (include colours)

not sure if this helps. let me know.

urine processing DAY THREE

Read biochemical tests

the GNB was Klebsiella pneumoniae
citrate pos
indole neg (kovacs reagent)
H2S neg
non motile
acid slant and acid butt on TSI, gas pos
urease pos
PAD neg (10% FeCl2)

C albicans due to presence of germ tubes (no restriction between germ tube and yeast cell)

Enterococcus sp due to aesculin bile pos (black colour)and resistant to bacitracin

S saprophyticus due to coag neg, MSA pink colonies, DNA neg and Resistant to novobiocin

urine processing DAY TWO Biochemical tests

Staphylococcus id
S saprophyticus is common cause of UTI in women and in men with indwelling catheters
only difference between S saprophyticus is its resistance to 5ug novobiocin
S saprophyticus is coag neg, MSA (pink colonies), DNA neg and novobioicin resistant.
so set up
DNA plate (stab and streak)
MSA (streak for single colonies)
coagulase (inoculate plasma with colony, incubate for up to 4 hours, remove and refridgerate if unable to read on same day)
seed CAB plate with suspension of org equivalent to McFarlands 0.5. Place novobiocin disc on plate)

GNB id
inoculate
TSI (stab and streak\
SIM
citrate *stab and streak)
PAD
urease

yeast id
set up germ tube
inoculate serum with colony
incubate at 37 degrees for up to 2 hours
make wet prep and examine for germ tubes which is pos for C albicans

Enterococcus id
inoculate BA plate. Place bacitracin disc in area of most growth (should be resistant)
inoculate aesculin bile (pos for Enterococcus)

urine processing DAY TWO

examine antimicrobial plate
any zone around disc indicates that the px is on antibiotics and will influence the significance of any growth of organisms
examine CLED plate
estimate the amount of growth
growth up to the squiggle in the middle of plate equals 100 000 orgs per ml of urine
growth up to a level below the squiggle decreases by a power of 10. (please see me if you dont understand this)

examine the BA Growth should represent totality of all orgs seen on other plates
examine MaC for LF/NLF (LF are pink, NLF are brown, transparent, colourless)
examine SAB for yeasts (distinctive odour)

NB! you must get used to the smell of bacteria. Orgs like yeasts, E coli, Klebs, S aureus have very distinct smells. Smells is one way of guiding you to a possible identity of the organism.

set up biochemical tests to identify any potential pathogens seen.
contd in next post

urine processing DAY ONE

day one
macroscopy of specimen
describe odour (if applicable) colour, turbidity, volume
microscopy of specimen
decant few ml into a centrifuge tube
centrifuge and make wet prep with sediment
examine using up to 40X obkective
examine for cells, crystals, casts, and bacteria/yeasts
if casts and crystal seen, name type (significant as it denotes type of kidney damage)
culture of specimen
use plates dependent on what seen in wet prep (use urine from original urine specimen container)
include BA (enriched medium, usually all orgs grow), Mac for LF/NLF (GNB), CLED (total colony count, streak for single colonies without flaming, use 1/1000 ul loop)
include SAB if yeasts seen in wet prep
ALWAYS remember potential pathogens found in urine
perform an antimicrobial test to dtermine if px is on antimicrobial therapy
make a suspension of B subtilis equivalent to McFarlands 0.5
seed a CAB plate using the suspension
place a sterile filter paper disc on plate
place a loopful (1/100 ul) of urine on disc
incubate all plates at 37 degrees, aerobically for 18-24 hours
lastly do a dipstick to determine any abnormal chemistry.
NB! Nitrites indicate bacterial activity i.e. reduction of nitrates