Interviewing Sarah Thompson

Although we had designed a schematic for the decision making processes that a doctor goes through when prescribing antibiotics, we wanted a more personal perspective to better understand the difficulties that doctors face.

We interviewed Dr Sarah Thompson, a microbiologist at a children’s hospital. Sarah is a medical doctor and specialises in microbiology. She advises doctors on antibiotic prescription.

First, we would like to see, from the point of view of a doctor, if patients indeed actively ask for antibiotics

“In the healthcare settings that you have worked in, have you or other healthcare staff been asked by patients for antibiotics?

Second, given that our device is mostly targeting medical staff, we would like to know if she thinks the current antibiotic prescription mechanism needs improvement.

Given the medical importance of antibiotics, do you think prescribing antibiotics based on clinical symptoms alone is appropriate?

Finally, we are interested in knowing what would make a good device to a doctor.

Ideally How accurate must the device be in order for it to be of use in inform your diagnosis/prescription?

"If you think about it, there are patients that clearly need antibiotics and patients that don’t. So you care about the middle group, if we assume without the test,they are gonna get (antibiotics) anyway, if it is sensitive but not brilliantly specific, if you got a negative you can stop the antibiotics. Whereas if you got a (false)positive, they would get the antibiotics but they would have got it anyway. If you(also) got a false negative, then what can you trust? Because you are having both false negatives and positives. Therefore, I think it will be most useful for being a rule-out test. And if that is what you are targeting, what you need is a very good sensitivity. You can have false positives but you have to minimize your false negatives.

In terms of how sensitive and accurate it needs to be, if you are targeting infections that are relatively mild, you can say it doesn't really matter anyway, cause if you are gonna do a microbiology test and they are not that unwell you can wait two days anyway.

In terms of how sensitive and accurate it needs to be, if you are targeting infections that are relatively mild, you can say it doesn't really matter anyway, cause if you are gonna do a microbiology test and they are not that unwell you can wait two days anyway.

I’d say it’d have to right majority of the time. You don't wanna be proven wrong and you don't wanna be not giving antibiotics to be the people that have (bacterial) infections. As soon as that happens a few times, (our device)it’d top being used. So I would say that you would target sensitivity over specificity. And the false negative would be a problem."

Do you think it would effectively reduce the number of antibiotic mis-prescriptions?

...Getting the reliability would be difficult. .. Blood culture, when people take bood, quite a few the positive culture that we get are contaminated from the skins. So when they take the culture they are going through the skin, either because the skin wasn’t adequately cleaned or because the technique they used to obtain or maybe they’ve touched something. Actually, skin floral gets into the culture bottle. And indeed potentially any bottles that you are collecting for your test and if it is detecting any bacterial then it would be positive, not because they got an infection but because they've introduced bacteria into it.

With any test like this, the challenge would be the samples you get would have to be sterile. If you are detecting the presence of bacteria, there would have to be a sample (with data) that you would ordinarily get if there were no infection.”

How much time ideally should the test take for it to be clinically practical?

“As quick as possible.”

Would two hours be ok?

“Probably. So you would be aiming at short as possible. It kinds of depends on which environment you are targeting. If it is general practice, it has to be quick, because they only have about 10 minutes appointment. Yes it is better to know better later that day. But it’s probably gonna be reasonably inconvenient for the GP. If you do a test and that takes two hours,particularly given how many people they see with infections again and again, you’re gonna have to recontact them.

...You can imagine that You are gonna have to say to them that we will let you know if you need antibiotics. But if you assume a number of them will do, you would need to recontact them later that day, they need to come in and get a prescription and take that to the pharmacist, so that’s 3 visits in a day…

So the added workload having to recontact people.. Depends on how tests you do on a day, if it’s something that would be using frequently then for a GP, waiting for the result means they would use less often.

If you want it(the device) to be a standard, does this patient have an infection(bacterial)... then the test has to be swift. In an outpatient clinics then it would probably to fairly comparable to the GP surgeries if they’re gonna use it.

If you want it(the device) to be a standard, does this patient have an infection(bacterial)... then the test has to be swift. In an outpatient clinics then it would probably to fairly comparable to the GP surgeries if they’re gonna use it.

Our device would contain a GM live bacteria. Would it be a problem to using the device in a clinical setting?

Not inherently. If I was to be judging you project, my expectations from an infectious and control point of view would be that it needs to be easily cleanable from the outside of the device. If it’s gonna move from patient to patient, you need to make sure it doesn’t transmit bacteria.

And with GM bacteria, as long as they don’t come out it doesn't matter.

You need to make it as easy as possible so people can use it and not make hazardous, say, some bits pop out. It needs to be a robust and enclosed device where the bacteria cannot contaminate the device and the people using the device.

...make sure the bacteria wouldn’t contaminate the sample that you are testing or If the device is contaminated with those bacteria and they get into the sample then the sample you are testing will always be positive.Also, it would have to have a disposable element to it. Otherwise, whatever you are using to get the blood would then be contaminated and you would always get positive.