DrVirgo
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Catalase Positive Organisms:
Staph (all)
Pseudomonas
Aspergillus
Candida
Enterobacteriaceae
-Citrobacter, enterobacter, E.coli, Klebsiella (which are all lactose +)
-Shigella, Yersinia, Proteus and Salmonella (which are all lactose -)
-Serratia (a slow lactose fermenter)
Are there any more?
(this is important to know because patients with CGD get infections with Catalase + Organisms, so if anyone can list any more, please post!) 
Thanks.
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| coolmavs
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It would be great if somebody could post the significance of the catalase and oxidase tests and the organisms concerned?
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| bactitech
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Catalase testing is done mainly on gram positive cocci in micro labs to determine the split between Staph and Strep species. That being said, catalase is also performed on a few other organisms for definitive identification when needed. We perform catalase testing on Campylobacter (should be positive), N. gonorrheae (positive), M. catarrhalis (positive). I have never done catalase testing on enterics, Pseudo, or Aspergillus. Diphtheroids are catalase positive, as are some anaerobes.
Oxidase testing is performed on ALL non-lactose fermenting organisms. There are a few lactose fermenters that can be oxidase positive - mainly Aeromonas. I teach all students that they MUST perform oxidase testing on NLF's. If oxidase positive, t throws the identification into a totally different arena than enterobacteriaceae. When we set up automated identifications, a little circle on the card must be filled in if oxidase positive so that the Vitek can identify correctly. The first thing I look for in a problem identification is whether the oxidase was done. If I question the result, I always repeat it.
Oxidase positive gram negative rods are mainly non-fermenters of glucose. There are too many to list here. It is a key test that must be performed on gram negative rods in order to come up with the correct identification.
Neisseria gonorrhoeae is an oxidase positive gram negative diplococcus. Oxidase testing HAS to be performed on this organism to properly identify it.
We use 3% hydrogen peroxide (drug store stuff) for catalase testing. We smear a bit on a glass slide and put a drop of 3% on top of the smear. It should bubble profusely right away. No reaction or a couple of anemic bubbles does NOT constitute a positive reaction. Care must be taken, if the bug to be tested is on blood agar) that the media underneat is not scraped up with the organism, as that can give a false positive reaction.
Oxidase reagent comes in commercial dropper vials. We either swipe a clean swab over a bit of growth on a nonselective medium and drop some reagent on it, or use filter paper on a clean petri dish half plate that's impregnated with a few drops of reagent. A positive reaction will yield a blue color. I personally like the filter paper way best, as it's easiest to do and to read. The paper can be dry and will last for about eight hours before getting discolored. It is important NOT to perform oxidase testing on MacConkey agar, as the agar color will not enable you to get a good reaction.
To be absolutely PURE when you do oxidase testing, you should use a platinum loop. The problem is that most micro labs don't buy these any more as their cost is prohibitive. I try to use an applicator stick when scooping growth rather than a nichrome wire loop.
Hope this helps.
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| DrVirgo
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Thanks for that extensive description.
You mentioned that N. gonorrhea is positive for Catalase? Is N. menintitidis also Catalase positive?
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| bactitech
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I'm not sure. I've only ever done it on N. gonorroheae. Our day shift does respiratory cultures now, so I haven't seen the bug in a few years. Sorry, don't know.
The main reactions for GC vs. N. meningitidis is sugar reactions. GC is positive for glucose only, and negative for sucrose, maltose, and lactose. N. meningitidis is positive for glucose and maltose, negative for sucrose tne lactose. The gold standard (which is hardly used any more) is CTA sugars. Most ID's are now done with commercial kits.
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| DrVirgo
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Great. Thank you!
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| coolmavs
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bactitech that was great explanation. Thank you, sure cleared a few cobwebs....
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| reet
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bactitech...thanks again for ur input...
APPRECIATED!!!!!
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| bactitech
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You're quite welcome.
As an observation, I think it's interesting how you guys learn microbiology, as opposed to the way bench techs learn micro.
For example, I would never memorize a list of catalase positive organisms. In my mind, I would split the gram positive cocci into Staph. and Strep. Staph are catalase positive, and strep are catalase negative, and then go from there. Catalase is not a test we routinely perform on gram negative rods, so I wouldn't even include that. There are a couple of gram negative organisms that we have to perform catalase on: Campylobacter and GC. Other than that, it is not a characteristic I associate with gram negs.
I likewise split gram negative rods into oxidase negative and oxidase positive organisms and go from there. Most of the oxidase negs are fermenters; most of the oxidase positives are non-fermenters. Those are the big splits, though. I stress to all new techs to ALWAYS perform oxidase on non-lactose fermenters. There are a couple of lactose fermenters that are oxidase positive (Aeromonas being the biggie that comes to mind) but on the whole, the NLF's are the ones that is it imperative that you have an oxidase reaction for in order to identify them. I have seen new techs forget to perform this vital test and get led down the garden path many times.
I realize that your exams group things differently (i.e. lists of things to memorize) - I just wanted to throw in my 0.02. 
Duh, it's late and I realized that I just repeated a lot of what I already posted, so have pity on this old lady. I just had my 57th birthday on Friday and I was up really early this morning so I'm ready to crash and I'm not thinking that clearly.
Have a great week everyone.
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| coolmavs
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Belated HAPPY Birthday Bactitech. Hope you have another 1 added to the number of microbiology years that you have already spent (before or after the existing 31 is your choice)
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| bactitech
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Why thank you coolmavs . It's nice to have a cheery message after a long day. I worked this weekend and Saturday was absolutely insane! Was there a full moon or something this weekend? The ER docs were going crazy ordering STAT rapid flus, RSV's, strep screens, tapping CSF's, drawing blood cultures, etc. etc. I've never seen so many specimens come in on a Saturday in my whole life! On top of that, we went to an upgrade of our computer supporting system today. It's slower getting things in for now until we know it cold, so that didn't help matters any. I'm certainly glad my weekend is over.
It's weekends like this that make you wonder how long you're going to hang out in labs? 
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| coolmavs
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As I said before Bactitech add the 1....before or after is your wish.........that is the amount that you are going to hang out in the labs!
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| Cedrick
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here it is
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| bactitech
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It is now July - we're more used to the computer system, but they're doing another upgrade end of this month and test ordering will slow down considerably - everyone is hating this one even more than the other one. Oh well.....nothing you can do.
Respiratory stuff has slowed down, but we're getting into "fancy tests on CSF's" season, due to West Nile, Equine encephalitis, enterovirus, and all those good ol' mosquito borne diseases. We perform enterovirus PCR in-house (not me - other techs) and are the only lab around who offers 24 hour TAT on this test from August through October, which is the season.
Make sure you dump out standing water anywhere around your house or apartment. Mosquitoes can breed pretty much anywhere. Tell your friends, also. We lab people don't want any more CSF's coming in!!
Yeah, I'll probably be in the lab another 10 years minimum. With the cost of health care escalating, who can afford to retire????
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| MRMAVERICK
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goood list
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| labtech+
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Norcardia. Common bacilli found in dirt, but really hard on immunocompromised patients.
Seems to me that should be getting more attention because of the increasing number of immunocompromised patients these days.
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| silver
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FA has nice flow diagram of all of this...easy to learn and remember
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| bactitech
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If you are suspicious of Nocardia, be sure to inform the microbiology lab. Also, order your culture for fungus also, as Nocardia is slow growing and may not show up on regular micro culture media before we sign it out. It will grow on fungal media, however.
The more you can tell us, the better we are able to accommodate your requests. We can supplement the set up protocol with a BHI (brain heart infusion) plate, which Nocardia seems to like, and hold the culture a few extra days.
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| cecille
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campylobacter are also catalase positive some campylobacter growth in CCDA are catalase positive anyone knows what type of campy are catalase neg and which type of campy are catalase positive??
thanks
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| cecille
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JUST WANT to add that Bacillus Cereus/ Bacillus subtilis??? are also catalase positive
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| tompat
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wow, thanks for that info,
anyways happy birthday to this thread
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| bactitech
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When we isolate Campylobacter from a stool culture, catalase must be positive in order to call it this genus, I don't have the flow charts available here, as I'm writing this from home. I do think Campy has to be catalase positive. I don't think there are negative Campylobacter sp.
I'm sorry I forgot about Campy when I wrote my first submission to this very long thread.
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| suaveman
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I believe someone had asked if N. Gonorrhea was catalase positive? According to Kaplan it shows that both N. Mening and N. Gonorr are both oxidase and catalase positive.
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| hedieh
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I was reading about CGD, and I googled for Catalase positive organisms, surprusingly I found this post on our forum, it is so helpful. So I digg it up for the others to use it. Very helpful for me! thanks guys!
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| mytime
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yeah very useful..Thanks. HEDIEH and tns. BACITECH.
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