How often are sputum cultures false negative? My son is currently recovering from a month of sickness including sinusitis that then settled into his chest. His sputum culture was taken 3 days after he finished 10 days of amox and had just started 3 days of augmentin. His sputum was thick yellow good sample and came back normal. I suppose he could have viral pneumonia but I almost wish it was something so we could do something besides empiric therapy. He is being treated with oral antibiotic for one month now and getting better along with albuterol/pulmicort. Any insights?
False negative sputum culture?
- Thread starter Julie7
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I'm pretty sure h flu and staph aureus are pretty normal growths in both cf and non cf patients. My son has cultured these a few times and was told they do not treat either unless there are symptoms. Sounds like the augmentin being used should cover this. Unfortunately it is the time of year most of us cf parents hate with the increased cold and flu germs being passed around.
I agree with Jshet. Culture results on the same day doesn't seem right. It wouldn't be enough time for the culture to actually grow anything! It's defintely possible they got his culture mixed up with someone else's. I've had that happen. Maybe call them and ask for them to double check on that because of the time line.
Our local cf clinic does the same darned thing. I'll get a call from the clinic the next day from the nurse saying normal flora. When DS was a baby the cf clinic in the City waited 5-7 days before releasing the final report. When he cultured H. Flu, he'd usually be all snotty and have a sinus infection -- augmentin for 3 weeks was prescribed. When he cultured non-mucoid pseudomonas he had no symptoms.
Sputum Culture results do not come back the same day. It takes at least 48 hours for the preliminary report; for example gram negative or gram positive bacteria. Then up to 5-7 days for the type of bacteria and sensitivities.. For example, sputum culture shows staph aureus and what antibiotic will work to kill it. Some sputum cultures can take even longer when looking for slow growing stuff. But in general, when my daughter has a sputum culture done I call after 6 days to know what she grew and what it is sensitive to.
Also, when my daughter is cultured it says on the order slip, patient has CF, the lab know how to handle these cultures. Once, my daughter had a culture done at her regular pediatrician's(can't remember why) It was back in 2 days and I do not think it was accurate.
Another thing; how did they obtain the culture? DId your child cough something up into a sterile cup? Or were they cough swabbed? My daughter has never coughed anything up into a cup. She just won't or can't. So they cough swab her, unfortunately this is not super accurate because it is not coming from deep in the lungs. So yes one could culture something in the lungs but not have it show up on culture because it was not obtained deep enough.
Hope you child continues to improve. My daughter is battling a blechy cough too
And i wonder if her last culture actually shows what it causing the problem..Time will tell. Hope I didn't confuse you.
Also, when my daughter is cultured it says on the order slip, patient has CF, the lab know how to handle these cultures. Once, my daughter had a culture done at her regular pediatrician's(can't remember why) It was back in 2 days and I do not think it was accurate.
Another thing; how did they obtain the culture? DId your child cough something up into a sterile cup? Or were they cough swabbed? My daughter has never coughed anything up into a cup. She just won't or can't. So they cough swab her, unfortunately this is not super accurate because it is not coming from deep in the lungs. So yes one could culture something in the lungs but not have it show up on culture because it was not obtained deep enough.
Hope you child continues to improve. My daughter is battling a blechy cough too
And i wonder if her last culture actually shows what it causing the problem..Time will tell. Hope I didn't confuse you.Thanks everyone. He was able to cough up a good sample. I left a message with clinic to ensure they did let it grow before finalizing. I can log on to see results which say final on the same day as culture. Maybe they can see something I cannot but I am double checking with the clinic.
B
BreathinSteven
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I agree with some of the other commentary... In my past experiences -- some bugs take much longer to grow out. If there is a bad infection -- they may have an initial indication in hours or a few days... But, they will re-examine the culture 1-2-3 weeks out and find other bugs have started to grow... Also -- my past understanding has been that when a culture is taken while you're actively taking antibiotics, or just stopped, that can inhibit the growth/proliferation of whatever bugs they were trying to kill. But those too may grow out after several days...
They can increase/add/change antibiotics if something grows out immediately/quickly -- but other bugs may take a while to show up on a culture. I don't necessarily find it unusual that they would tell you what's growing out the next day (or, what's not growing out) -- but that probably shouldn't be the final answer. If they say, "negative" or normal flora -- I would hope they qualify that with "at this time"... Love, Steve
They can increase/add/change antibiotics if something grows out immediately/quickly -- but other bugs may take a while to show up on a culture. I don't necessarily find it unusual that they would tell you what's growing out the next day (or, what's not growing out) -- but that probably shouldn't be the final answer. If they say, "negative" or normal flora -- I would hope they qualify that with "at this time"... Love, Steve