Campylobacter identification

Gram negative small curved, spiral, seagull wings bacilli
growth at 37 and at 42 degrees
Darting motility in wet prep
Oxidase pos
Catalase pos
Sensitive to nalidixic acid 30ug
Resistant to cephalothin 30ug
Campylobacter jejuni is pos for hippurate hydrolysis
Campylobacter coli is neg for hippurate hydrolysis

Carriers

The following orgs can be carried by healthy people
Corynebacterium diphtheriae
Haemophilus influenzae
Streptococcus pneumoniae
Salmonella typhi
Vibrio cholerae
Staphylococcus aureus

WIDAL test

This is a serological test for typhoid and paratyphoid fever
Set up 2 rows of 6 tubes each
make dilutions of 1/40 up to 1/1280
Add the O antigen and H antigen to separate rows
O antigen is blue, and O agglutination is granuler
Vigorous shaking of the tube when reading will not destroy the agglutination
H antigen is pink, and H agglutination is floccular (cloud like)
Vigorous shaking will destroy the agglutination which is rectified by light centrifugation
O are incubated at 37 degrees
H are incubated at 56 degrees

This test is done when MC and S is negative. Patients dont visit the Dr at the appropriate time.
The organism is shed in the blood in weeks 1-2, in urine in weeks 2-3, and in stool indefinitely.
The name of the serotying is the Kauffman White scheme. The types of antigens tested for are the O and H. The Vi antigen is tested for to determine if the patient is a carrier

Neisseria species

2 pathogens of interest:
Neisseria meningitidis also called meningococcus
Neisseria gonorrhoeae also called gonococcus
GNC which is oxidase positive and produces beta lactamse
grows on enriched media (BA and CHOC) at 37 degrees
does not grow on general purpose media like NA
Non pathogens or commensals grow at room temp on enriched media and on NA at 37 degrees
CTA sugars are cysteine lactose sugars - enriched media in tubes which support the growth of Neissera. Has added CHO to aid in identification, look for acid production
Neisseria gonorrhoeae produces acid from glucose
Neisseria meningitidis produces acid from glucose and maltose
Neisseria lactamica produces acid from glucose, maltose and lactose
B catarrhalis produces no acid from glucose, maltose, lactose or sucrose
In the Gram of the specimen, look for the kidney shaped diplococci IC or EC in WBC. This needs to be reported to the Dr.
Be careful when making the smear and inoculating agar plates:
roll the swab over the slide/plate. In the smear this is done to preserve the morphology of the organism.
N meningitidis is encapsulated so a Quellung reaction can be done
culture plates are incubated under increased carbon di oxide

Pseudomonas aeruginosa

this is an oxidative organism, GNB, which produces 2 pigments, pyocyanin and pyoverdin. On NA, the colonies have a characteristic greenish colour. It also produces a distinct smell. Open the plate and pass it quickly past your nostrils. Dont inhale too eagerly and dont leave the plate open for long.
the identification rests on:
colonial morphology on agar plates
characteristic colour and smell
reactions in OF/Hugh Leifson medium acid in open and closed tube, oxidative reaction
oxidase reaction positive

this organism is very fond of damp/moist areas so it colonises readily anything that has "standing" water. It has a strong unhealthy relationship with cystic fibrosis patients. These patients produce the alginate gene. This gene is activated to produce alginate which surrounds the cell wall of the organism and therefore protects it against phagocytosis.
Now picture this:
the organism produces many toxins/enzymes that destroy elastin, collagen, lipase which all allow the organism to spread the infection
the pigment pyocyanin stops other bacteria from causing an infection at then same time
the organism destroys the RBC and produces toxic effects in the patient
the organism is resistant to most of the antibiotics used for GNB infections. So any antibiotic used will produce serious side effects in the patient
What a nasty little buggar??
And to top it all, it is capable of growing at room temp, body temp and at 42 degrees. So a fever in the patient wont kill this little horror!!!

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