02/20/2017 06:31 EST | Updated 02/21/2017 06:44 EST

How Travel Helps Antibiotic Resistance Spread Around The World

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sneezing woman sick blowing nose with white background

With all the wintry weather affecting the country, Canadians cannot be blamed for seeking out warmer climates. The promise of sun, sand, and sea may seem like the perfect antidote to the constant struggles of the snow and those cold winds. Yet, there is an inherent risk associated with travel in the form of infection; a dream vacation may quickly turn into an onslaught of unfortunate symptoms.

Between 2011 and 2012, some 1,500 people sought medical attention after returning back to Canada. This number may appear to be small in comparison to the millions of Canadians travelling abroad each year. Yet these cases only represent those who were ill when they returned and not necessarily reveal who might have been sick while on vacation. Countless more suffer and recover while they are away.

Though infections can affect almost any area of the body, on average, about half of the troubles are gastrointestinal, usually in the form of traveller's diarrhea. While this condition usually is not life-threatening, the symptoms certainly can ruin a vacation. Thankfully, most of these troubles are caused by bacteria and can be treated with a simple antibiotic prescription. Within a few days, the pain and those runs fade away allowing individuals to continue enjoying their trip.

There is, however, a potential unwanted consequence of this action. While the target of the symptoms may be eliminated, the use of antibiotics may allow for colonization of the gastrointestinal tract with antibiotic resistant bacteria. As a result, the traveler unexpectedly may end up being an importer of a public health threat.

For years, this route of spreading antibiotic resistance was considered to be a theory but in 2011, a group of Finnish researchers confirmed the suspicion. They examined the fecal matter of 430 Finnish travelers who had suffered from traveler's diarrhea and had taken antibiotics while away. As expected, up to four out of every five individuals was carrying resistant bacteria. As for the source of the strains, most were acquired while abroad.

When this study was performed, the antibiotic resistance crisis had not yet been called by the World Health Organization. But when the announcement was made, certain types of antibiotic resistance became significantly more important. This included fluoroquinolone resistance, in which bacteria can survive in the presence of some of the most powerful drugs such as ciprofloxacin, or as most people call it, Cipro. Unfortunately, the 2011 study did not examine the risk for this particular type of bacteria.

That changed earlier this month. Certain members of the same group of scientists went back to the feces to determine if antibiotic use during travel was a risk factor for spreading fluoroquinolone resistance. The results revealed travelers may need to start thinking about infection prevention instead of antibiotic control.

As in 2011, the group examined the 430 traveller specimens but in this case, only those from individuals who had taken a fluoroquinolone were selected. Then, just as before, the samples were examined for any presence of resistance.

When the results came back, the picture was indeed gloomy. Almost all of the bacteria isolated from these individuals were able to resist Cipro. This was expected as using the drug would help resistors survive and thrive. This revelation on its own was enough to recommend against using this antibiotic when travelling. However, there were some surprises in store.

The first happened to be a lack of any link between a certain geographical region and the presence of resistance. This suggested fluoroquinolone resistance was common in most areas of the world as early as 2011 when the original samples were collected. This not only revealed the widespread nature of this type of resistance but also implicated even back then, there were no safe zones from resistant strains.

Another surprise came in the form of age. Elderly people were more likely to carry these types of bacteria, regardless of what drugs were taken. This revealed the importance of a strong and balanced gastrointestinal microbial population particularly in older individuals who are more prone to shifts in microbial balance.

The final unexpected result came in the form of resistance linkages. Although this study focused on fluoroquinolones, many other types of antibiotic resistance were found in the same species. This meant the use of any antibiotic, not just one like Cipro, could potentially lead to spread of several types of resistance.

The results of the study reveal a trifecta of concern with respect to travel and antibiotic use.

First, antibiotics may cause a shift in the microbial population as they kill off those sensitive to the drug.

Second, this alteration may allow resistant bacteria to thrive particularly in the elderly.

Thirdly, the use of a single antibiotic may still lead to multiple forms of resistance due to those genetic linkages.

Taken together, the authors had little choice but to suggest antibiotic use should not be condoned unless absolutely necessary.

This recommendation may be music to the ears of public health officials but to travelers, this may place an increased onus to avoid infection. In Canada, the government has helped relieve some of that burden by offering excellent tips to help you stay safe. In addition, travel doctors are an excellent resource to improve safety while abroad. These professionals know exactly what troubles may lie ahead and more importantly, how to avoid them.

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