We've all had antibiotics for one reason or another but do they work alongside the immune system to give it a little helping hand or are they completely independent?So, given to someone with a weakened immune system should that patient be given a slightly higher dose, or longer course?
Halfway through second course of Doxycycline for another chest infection and not observing much joy!
Not feeling the love from haematology either. They can't see me for 3 to 4 weeks!
Written by
happyclappy
To view profiles and participate in discussions please or .
Antibiotics that are "bactericidal" generally do not need support from the immune system to work. Those that are "bacteriostatic" generally need a bit of help from us. This concept is somewhat dose related; a high enough dose of an otherwise bacteriostatic agent may be bactericidal. I was taught most antibiotics are bacteriostatic, I am not sure if this is still true with all the new drugs since I quit pharmacy.
In my pharmacokinetic classes, there is a concept called "area under the curve" needed for various bacteria, to be killed with the help of normal immunity. This curve is a time and dose thing. So if one doesn't have normal immunity, one needs longer because the "area under the curve" changes a bit, as the body is not kicking in the help expected. Since we see more drug side effects as blood concentration rises, it's most common to extend the course of therapy. Some docs may also change the dose. A lot depends on what bug they are looking at, side effect profile of the drug, whether the drug affects liver or kidneys or heart, etc etc. But for us immune compromised, we may need 2-3 times the "standard recommendation" for number of days. Which is why I recommend when you can, ask for actual MIC's on an organism for serious infections. There are calculations on can do, to help determine if a higher dose is needed for organisms that seem resistant to standard doses. I don't ask for MIC's on minor or initial infections, or if a treatment seems to be working, but I did when my skin MRSA came back a second time. If I recall correctly, the second time I got treated for 3 weeks instead of 10 days.
These days I usually get Co-Amoxiclav for everything and at least a week for "minor" infections, longer for more serious ones. When my body was at its lowest, before I started treatment, I had about 5 courses of antibiotics and it still didn't help. Just recently again, 3 courses of antibiotics within 2 months. They should do a swab to see if you perhaps need different type of antibiotics. Prophylactic antibiotics might be something to discuss and having your immunoglobulins tested too. Get them to refer you to an immunologist.
Sorry, using medical jargon again. MIC stands for Minimum Inhibitory Concentration. It's defined as the minimum amount of drug needed to prevent a bacteria from continuing to grow. There are a number of methods nowadays to do this (see link). Various antibiotics are tested against a bug the patient has. Depending on whether or not the bug grows X amount, it is determined that a standard dose of the antibiotic either 1)lets the bug continue to grow, or 2) inhibits/stops the growth. To save time and money, because knowing the exact MIC isn't always *needed* to treat most infections, most antibiotic sensitivity reports simply report that a bug is sensitive(S) or resistant (R). The amounts of antibiotics used in the test correlate with standard antibiotic doses commonly used. This works very well most of the time.
But sometimes there are complications. What about a bug that is extremely close to R? It can happen, and so even though the report says sensitive(S) the bug actually is not getting inhibited as much as expected. What about patient drug allergies? What if a drug is unavailable? For various reasons (in my case, a potential for sepsis from a documented MRSA skin infection in an immune compromised patient who does not spike a temperature At All since diagnosed with CLL), more exact measurements can be asked for, to help calculate an "optimum" dose when the standard one may not, or is not, working. These measurements are the actual numbers of the MIC's for the various antibiotics. So instead of a report that comes out of the lab saying "S" or "R", there are numbers next to the letters. They are compared against the standard numbers often found for that bug against that drug, and one can see if a bug is extremely sensitive to one or the other of the selection of S drugs, compared to others closer to the R number. And if you need to use an R drug for whatever reason, the R number will guide you as to how the dose needs to be adjusted. This takes extra time, costs extra money, and (in the US) not every lab offers this. Larger hospitals/medical centers in the US often have the equipment and staff trained to do these.
There are other factors used in determining which drug to use, not just the MIC. Where is the infection, does the drug penetrate that area readily, allergies, renal or hepatic function and how the drug is metabolized,etc.
Sofia, thanks for your informative answer. Do they use MIC's for antifungals? Would this idea of a longer course for immune compromised be similarly used with antifungals?
I had a difficult to clear chest infection for the first three months of this year. I wonder why you have been given the same antibiotic twice when the surviving bugs may be the ones resistant to those particular antibiotics?
I was given four different kinds over 14 week period. Am early stage CLL so we started me off on amoxicillin. Then doxycycline. Then coamoxiclav. Then azithromycin. All of them worked fast. Only the fourth completely cleared the infection.
I was given doxycycline when I had a bad cold prior to a holiday just in case it developed into a chest infection, thankfully it didn't but I was advised to keep them in reserve. I also have a pack of Nitrofurantoin to deal with possible UTIs.
I think Sofia has covered your question really well.
My point is that GPs are still too ready to prescribe an antibiotic for what is clearly an acute infection, without knowing what organism they're trying to control.
At my local surgery I see any one of six or more doctors for an appointment. For an infection one might prescribe penicillin; another a more specific Ab, because he/she is aware of the growing problem of drug-resistant bacteria; another might request some lab tests to ascertain whether the infection is a bacterium and if so which, before prescribing or not.
The evidence of overprescribing and its adverse consequences for health are clearly written in the seasonal pattern of C Difficile infection, which peaks around 4-5 weeks after the peak prescribing season for antibiotics, which is mainly in response to chest infections associated with influenza sciencedirect.com/science/a... The issue is that even a single course of broad spectrum antibiotics can profoundly disrupt the patient's gut's microbiome, and with it the immune system, rendering the patient more vulnerable than before to certain diseases. Not only pathogens healthunlocked.com/cllsuppo... but cancer too bmccancer.biomedcentral.com...
I finished O&V treatment in October 2022. I was plagued by serious chest infections both before and after treatment. I resisted taking a permanent antibiotic that was suggested by my consultant. I relented and since November I have taken a daily antibiotic. It has been truly transformational. No side effects or chest infections yet and I had been hospitalised a few years ago with pneumonia. A winter with no infections has been great news for me.
My advice is to go for it. It has transformed my life thus far.
HiWhich antibiotic was described to you on a daily base - I think I should discuss this option with my doc given a sinusitis lasting 4 months now. I am 7 years in remission after 3,5 years of V+O.
I did have some antibody blood tests after V&O and I then had some repeat vaccinations for flu, covid and pneumonia. My consultant also spoke to an immunological expert.
Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.
Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.