People comment that my videos are easy to understand. Have you read the theory behind the procedure in the video?

The purpose of Coombs reagent is to help the IgG antibodies that may be on the surface of the red blood cells connect to other red blood cells in the tube thus to produce visible agglutination. IgG antibodies do not cause RBC agglutination very well, so the Coombs reagent helps this happen.

@@patricktracy9947 Thank you so much

It;s the potentiator Low Ionic Strength Solution (LISS).

Yes, that is LISS.

@@patricktracy9947 thank you ❤️ from india

Hi kk...your observation is correct, and I address it in the notes section.

I have never seen it performed on nutrient agar, so I can't answer your question.

Sir what happened to you no reply

An antibiotic disc placed on a blood agar plate will have a certain concentration of the antibiotic in it as determined by the manufacturer. Based on the manufacturer's guidelines, usually a measured zone of no growth around the disc is how we measure whether an organism is sensitive or resistant. For example, if you make a lawn of Streptococcus pneumoniae on a blood agar plate and put an optochin disc in the center of it, a zone of 18 mm of no growth around the disc may be considered sensitive thus positive for Streptococcus pneumoniae.

I made a mistake instead of streptococcus I was checking staphylococcus saprophyticus I put novobiocin I inoculate organism and placed nv novobiocin for nv originally bacteria shows resistant so it means it is s saprophyticus I cannot find any grth around the disc not only around the disc in the inoculated area it shows resistant to that antibiotics so my doubt is that bacteria is staphylococcus saprophyticus or any mistakes

I can't answer that question. You have given me too little information.

MacConkey is a selective/differential plate for growing Gram-negative rods from Enterobacterales like E. coli, Klebsiella, etc., not for growing fastidious Gram-negative rods like Haemophilus. Gram-negative cocci like Neisseria will also not grow on it.

Selena, I don't clearly understand your description of the situation and your questions, therefore I don't feel comfortable replying to them.

@@patricktracy9947 what i mean why we do the antibody screen test rather than the cross match ? I really don't understand this test ?

@@patricktracy9947 when a paitents needs blood transfusion we normally do the cross match test in order to give the compatible blood bottle right Now in the screening test i got confeused how we will give a blood bottle ? Did u get my question right

@@selena5979 Every blood bank will have its own SOPs (Standard Operating Procedures) which will determine which testing is performed before blood products can be issued to a patient. All patients who may need blood products will have a type and screen done on their blood. I would say most, if not all, will do a crossmatch. There are various tpyes of crossmatches including computer and serological. Serological can be immediate spin or AHG. All testing depends on the lab's SOPs.

@@patricktracy9947 oh so it depends on the sops .. now i get it thank u for ur answer dr.patrick 🤝🏻

Since the organism is growing on MacConkey, is oxidase negative and is swarming on sheep blood agar, it is probably Proteus species, either vulgaris or mirabilis.

Yes, Candida can be a stool pathogen although it is rare. Candida is an opportunistic pathogen so if normal stool flora is disrupted, Candida may have a chance to gain control of the bowel flora.

There is no reason why you can't count colonies from the MacConkey or CNA plates.

@@patricktracy9947 thank you for responding . So you can count on any plate but the type of steaking is diffrent , it's not but quadrant , am i right ?

@@staisi2012 You can count plates if a calibrated loop is used to set them up. Urine cultures are usually the only culture type that use a calibrated loop. Other culture types like sputum where we don't use a calibrated loop and just streak for isolation may use a system of quantitation like "rare, few, moderate or many".

@@patricktracy9947 I understand sir , thank you so much , i really appreciate it .

Please

​@@priyak6945 We can't really identify an organism without specific biochemical or molecular testing. We can, however, give the doctor a preliminary report. For example, if I read a urine culture after 24 hours of incubation and saw 50,000 CFUs/ml of an oxidase-negative colony that is lactose-positive and has a fried-egg apperance on MacConkey agar, I can report "50,000 CFUs/ml of probable E. coli. Identification and susceptibilty results to follow"

Can by experience

@@priyak6945 With experience you can suggest what the identification of an organism is, but the identification needs to be confirmed with molecular or biochemical testing.

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I'm glad it was helpful.

It helped me so much that I revisit it from time to time for work lol ❤🎉

I am glad that you now understand?👌

Hi Priyak, I don't have experience with diluting tracheal aspirates.