Culture and Sensitivity Report (HOW TO INTERPRET)

[ResonantEcho]

According to the following information, what medication should be prescribed? And can someone explain how to read the report and the meaning on what is reported?:

Release D/T: >100,000 CFU/ML GRAM NEGATIVE RODS
>100,000 CFU/ML ESCHERICHIA COLI

E COLI
Antimicrobial MIC mcg/ml Int
--------------------------------------------------------
AMPICILLIN 4 S
AMOX/CLAV ACID <=8/4 S
AMP/SULBACT <=8/4 S
AMIKACIN <=16 S
CEFAZOLIN <=8 S
CEFOTAXIME <=8 S
CEFUROXIME <=4 S
CIPROFLOXACIN <=1 S
NITROFURANTOIN <=32 S
GENTAMICIN >8 R
IMIPENEM <=4 S
LEVOFLOXACIN <=2 S
PIPERACILL/TAZO <=16 S
TRIMETH/SULFA <=2/38 S
TETRACYCLINE <=4 S
TOBRAMYCIN 4 S
CEFEPIME <=8 S
AZETREONAM <=8 S
CEFTRIAXONE <=8 S
TRIMETHOPRIM <=8 S

Guessing I would say I should have been prescribed TRIMETH/SULFA. Was prescribed LEVOFLOXACIN.

[alan]

Do a search for the number 100,000 - I believe the nurses have said on numerous occasions that if the count is above 100,000, you should be prescribed an antibiotic. My memory isn't the greatest, so see what the search shows you.

[JGNI]

It was Sensitive to everything but gentamicin anyway, the doc picked levofloxacin because he feels comfortable with it and is probably avoiding TMP-SMX because of frequent adverse events like skin rash. As I said it often, in vitro sensitivity is not the whole portrait. I hope you get better on levofloxacin.

[ResonantEcho]

Originally Posted by JGNI

It was Sensitive to everything but gentamicin anyway, the doc picked levofloxacin because he feels comfortable with it and is probably avoiding TMP-SMX because of frequent adverse events like skin rash. As I said it often, in vitro sensitivity is not the whole portrait. I hope you get better on levofloxacin.

So what do the numbers mean?

He originally prescribed me Levofloxacin before knowing what bacteria was present. A few days after taking final pill (7 days, 1 a day), I started noticing strings of something or another coming out of my bladder (some here have described it as looking like egg whites). However, I wasn't running a fever. Now the egg whites have subsided but urine is VERY cloudy but I am still not running a fever. I just have some discomfort in my stomach.

He prescribed me Trimeth/Sulfa (2 a day for 10 days). I noticed a few messages here in the past said if fever wasn't present anti-biotics should not be taken. Should I hold off and see if the cloudiness eventually subsides?

From report, am I correct by saying Trimeth/Sulfa did show to be the most sensitive to bacteria? Then Amox/Clav Acide and Amp/Sulbact? Then Ciprofloxacin? Levofloxacin being 5th sensitive?

[SCI-Nurse]

The report shows >100,000 bacterial colonies of the bug e.coli.
A UTI is present when the colony count is >100,000 though infections are usually only treated when the colony count is present along with a fever or a rise in the wbc count. Most people with catheters will show >100,000
counts all the time, called colonization.

The sensitivities show the drugs that your laboratory has tested against this e coli germ. If it is "S" sensitive, it can work effectively with e coli. The MIC (minimum inhibatory concentration) is the dilution of this drug at which the germ can no longer grow. All of the "S" meds usually work but some clinicians use the MIC to guide them in more complex situations.

AS mentioned above, the urine culture results are valuable but the choice of antibiotic is also determined by allergies, ease of dosing and pts compliance history.

AAD

[JGNI]

ResonantEcho,

You are right by understanding that the lower the MIC the better, meaning that you will not need to reach very high concentrations of the antibiotic to kill the bacteria, that's the concept. Those in vitro analysis are telling you just that. BUT, all antibiotics are not reaching the same concentrations everywhere in your body. So if the antibiotic is mainly excreted in the urine, no matter if the MIC of this antibiotic is high, it will probably exceed it there in the urine and it will work. On the other hand, even if an antibiotic had a low MIC (it's all theory here), if none of it was to reach your bladder it would be of no use. Determination of susceptibility for most antibiotics (don't put nitrofurantoin among these) is established on the expected concentration you will be able to reach in your blood so that if the bacteria gets there (that's where it can become life threatening) it will be killed, R if it will not, S if it will. So you understand it can be different for urine.

Here are some factors influencing the choice of the antibiotic:

- Susceptibility patterns
- Safe achievable serum levels
- Distribution of antibiotic in tissues
- Route of excretion
- Toxic side effects
- Existing or developing renal or hepatic failure
- Absorption characteristics
- Existing or developing allergic reactions
- Antibiotic interactions with other drugs
- Cost

You usually treat infections when symptomatic, which means anything causing you problems, not just fever. If you are nauseous, even without fever, it can be a good reason to treat it etc. Many factors are involved, the PERSON is treated, not just lab results or symptoms, so it is hard to give a clear answer to when to treat or not.

By the way, in my experience, levofloxacin once a day has never been a very good choice in complicated UTI's (ours).