This article points out problems within the U.S., but only touches on the fact that the U.S. is a country that has millions of visitors and immigrants, many of whom come from countries where antibiotics are handed out too often.

In many parts of the world, pharmacies aren't as tightly regulated or monitored and often sell medication upon request rather than prescription. In my experience, lots of people head to the pharmacy instead of the doctor, because the doctor or hospital will make the diagnosis and then either issue a prescription, which can be filled in-house or filled at a pharmacy at a lower cost.

Pharmacists usually have little medical training, if any and simply note what prescriptions are filled and for what ailment. People that head to pharmacies tend to tell pharmacists their symptoms and then the pharmacists will generally sell the person several medications in the hope of catching it and from what I've seen, since tetracycline antibiotics have become less effective lately, pharmacies are regularly selling heavy-duty stuff like Cipro.

Another thing that I saw in Vietnam, was that hospitals don't provide food or water to patients and so families either bring food and drink in, or patients go out to eat at street stalls or get food from street vendors just outside the hospital. Often, these places don't really wash the dishes off, instead opting to rinse them off in a tub of water since there is no real access to water on the street. Not surprisingly, Vietnam is a country where antibiotic resistant TB is flourishing.

Unfortunately, this model of food and beverage service is not confined to Vietnam, but is fairly common in SE Asia. I'm not sure about China or India, but I think it's likely to be similar.

When all this is added to the amount of people travelling in and out of the U.S., concern is definitely justified.