When are just-in-case antibiotics justified, who’s most at risk (it may surprise you) and what you can recommend beyond basic hygiene advice…

At best traveller’s diarrhoea is a nasty experience. At worst, it can be fatal.

It remains the most likely infection in travellers, says Associate Professor Bernie Hudson, director of microbiology and infectious diseases at Sydney’s Royal North Shore Hospital.

People visiting friends or family are at particular risk, as they are less likely to take adequate precautions and more likely to be exposed to pathogens.

Some causes are clearly vaccine preventable, such as typhoid and hepatitis A, and most GPs would be well-versed in offering these vaccines.

More than 15% of cases are associated with enterotoxigenic E. coli strains, and many patients ask if they can have a script for antibiotics, just in case.

For the most part, Associate Professor Hudson recommends against this, as the evidence is particularly poor, and multidrug-resistant organisms are becoming an increasing issue.

Where a just-in-case script for antibiotics does seem clinically appropriate, he says azithromycin is the usual choice. He also recommends against routine antibiotic prophylaxis for traveller’s diarrhoea.

He prefers to focus on other preventative options. Food and water hygiene remain the mainstay advice.

Associate Professor Hudson recommends patients concerned about traveller’s diarrhoea consider hyperimmune bovine colostrum powder, marketed in Australia as Travelan. “That stuff definitely works,” he says. Ideally it is taken with every meal, so patients need to plan their supply in advance, and might find it tricky on longer trips.

“That’s where Dukoral comes in,” he says. It has been some years since American evidence suggested this oral cholera/ETEC vaccine was not very effective, but Associate Professor Hudson says it remains useful in patients with a history of traveller’s diarrhoea, especially before longer trips. The Australian Immunisation Handbook recommends it for travellers aged 2 or older who have a high risk of acquiring diarrhoeal disease and are travelling somewhere with high risk of exposure to cholera.

For a patient on a PPI headed to a tropical country, he almost always recommends Dukoral before the trip and Travelan during it.

“The elephant in the room is the proton pump inhibitor,” Associate Professor Hudson explains. “Gastric acid is the first line of defense against many of these things.”

He notes that patients will often ask about other just-in-case antibiotics. Again, he tailors his advice to the individual in question. “For a female with a UTI history, it is definitely reasonable,” he says, and he recommends they also carry their anti-candida treatment of choice. “That also applies to females using doxycycline as malaria prophylaxis.”

For the most part, he does not recommend other just-in-case scripts. “If you have a chest infection that’s bad enough to be needing antibiotics, then you need to be seeking healthcare.”

Non-directed antibiotic usage tends to be more risk than its worth. “Many studies are now showing people traveling to developing countries return with a higher rate of carriage of multi-resistant gram negative organisms,” he says. “Taking antibiotics while you’re over there just makes it worse.”

You can listen to an extended version of Associate Professor Bernie Hudson’s recent travel medicine lecture here.

This article was written independently, with no input from any of the manufacturers of products that are mentioned.