Friday, 26 October 2007

Microbiology--- CAMP TEST (week 19)

hey to all!!!

I'm posting for week 19!!! TIme passed super fast...
I saw ying ying's posts abt CAMP test but what i'm abt to post is a bit different from her.

Here i go...

For those who had been to micro lab, you should pretty well known with GPB/GPC/GNB/GNC.
Here i'm going to introduce you to ARCANOBACTERIUM HAEMOLYTICUM.

CHARACTERISTICS:

--- gram postive rods with pointed ends

---catalase negative
---small colonies, may be smooth, mucoid, white, dry
---B-haemolytic
---It will not grow on MacConkey agar
--- Facultative anaerobe

Certain organism such as Group B streptoccui able to produce a factor that acts synergistically with B-hemolytic of S.aureus subspec. aureus on sheep blood. The purpose of test to determine the organism's ability to produce and elaborate CAMP factor. The production of a-hemolytic(a-toxin) by clostridium perfrigen also demostrate the synergistic phenomenon with CAMP factor. If Phospholipase D is produced by organism, the CAMP reaction would be inhibited.


Medium:
TSA with 5% sheep blood agar (BAP)


Procedure:
1) preheat 35'C. Ensure plates are dry.
2) Using inoculating needle, streak B-lysin substrate organism in a straight and across centre of BAP
3) Streak QC stain ( about 2-3cm) perpendicular to S.aureus inoculum without touching the Staphylococcui
4) Incubate CO2 35'c incubator for at least 24 hours
**Note: the arrow head means +ve CAMP results
The curve head means -ve CAMP results



MY senior said that normally she will do another REVERSE CAMP test(RCT) to confirm the results from CAMP test.


PRCT-- production of a distinct crescent hemolysis at junction between streptoccus agalatiae streak and test organism.

NPRCT-- No constriction of band of hemolysis






**Note: Postive reaction

Limitation:

--> size of zone is depend on the amount of bacterial product and its diffuse rate through the medium

--> inocula should be sufficient to produce confluent growth. The extent and intensity of lysis depends on the size of the staphylocuccus inoculum. If the inocula is too light, reaction would be weak.

--> If the inocula are not perpendicular, production of arrow heads will not appear. False Negative occur.







ELaIne

SEE ya soon!!!





11 comments:

ALsubs said...

hi elaine
For ARCANOBACTERIUM HAEMOLYTICUM,what type of specimen is it normally present?
Which disease is it related to ?
liu qian here.
thanks !

pei shan said...

hi elaine,, why i din see this test in my micro lab... so cool... btw why it doesnt grow on maconkey agar?

MedBankers said...

hey liu qian,

A wound swab is normally sent too the micro lab as arcanobacteria is found in deep wound.

As arcanobacteria is found in wound, it will lead to skin manifestation(inflammation,pus etc..)and release of extracellular toxin. As one of their characteristic (hemolytic), it will cause serious bleeding too!!

hope it answer yr doubt
elaine

MedBankers said...

hey peishan!

MAconkey agar is a selective medium (it contains specific antibody that will inhibit the growth of arcanobacteria). heee! And it is more easy to spot arcanobacteria in sheep blood agar, because it is hemolytic!

elaine
miss u!

Debra said...

Hello,

I'm not familar with these terms : GPB/GPC/GNB/GNC

All i see is alphabets. T_T. Can you clarify?

People seem adverse to my posts, no qns at all! Though i suppose, that is a good thing for me XD.

- Debra, TG02

peishan said...

i know the answers... can i reply on your behalf, elaine? haha...

MedBankers said...

hey everyone,

GNB-gram negative bacilli
GNC-gram negative cocci
GPB-"positive bacilli
GPC-"positive cocci

debra don worry! PEi shan welcome to correct me if i'm wrong. i think i spell wrongly.. hee

elaine

first6weeks said...

hihi Elaine,

in what cirumstances, this test is order?

Juexiu
tg02

peishan said...

correct this time... ^^

Distinction in Disaster! said...

hi elaine,

can u elaborate more about ARCANOBACTERIUM HAEMOLYTICUM, like the clinical significance and there is some circumstances that the bacteria didn't grow after 24 hours incubation, what will you do?

Lizzie

MedBankers said...

hey jue xiu,

normally the med tech will first identify whether it is a gram neg or pos, followed by catalase test. There is a flowchart done by the pathologist in microlab. Med tech will follow the chart leading to arcanobacteria. i think different lab will be different in identify microoganism

elaine