a riskAntimicrobial resistance acquired abroad

An organism that survives the drugs meant to kill it, carried home in or on a patient who was treated in a hospital where such organisms are common. The CDC names carbapenem-resistant Enterobacterales and Candida auris as the two that "appear to be more common in some countries where U.S. residents travel for medical tourism", and asks US hospitals to screen anyone who spent a night in a healthcare facility abroad within the previous six months.

The link between hospital travel and resistance was established by a single paper. In 2010 Kumarasamy and colleagues reported a carbapenem resistance gene, blaNDM-1, in 44 isolates from Chennai, 26 from Haryana, 37 referred to the UK's national reference laboratory, and 73 from other sites in India and Pakistan. The gene sat mostly in Escherichia coli and Klebsiella pneumoniae, which were resistant to everything the authors tested except tigecycline and colistin, and it sat on plasmids that transferred readily between organisms. Case review found that most of the UK patients carrying it had travelled to India or Pakistan within the past year, or had links to those countries.

The paper was contested hard — the Lancet Infectious Diseases carried fourteen published comments in the three months after it appeared — and the naming of the enzyme after a city was part of what was contested. What was not in dispute was the mechanism: a plasmid moves between species, a patient moves between countries, and the two movements compound.

Inference — the loss here is carried almost entirely by the receiving system. A colonised patient is not ill and presents no claim; the cost appears later as a side room, contact precautions, a screening programme, and an antibiotic course that may run to months. Nobody bills it to the operation that produced it.

Screening is a swab, and in the United States admission screening for carbapenem-resistant Enterobacterales is available free through the Antibiotic Resistance Laboratory Network. The CDC asks facilities to take an explicit travel history, including any medical care received abroad, and to report suspected or confirmed cases of unusual resistance to public health authorities so that clusters are recognised — returning patients present near home, which scatters an outbreak across jurisdictions before anyone sees its shape.

As of 16 September 2026 no destination country publishes a resistance rate for its international patients, and no source market publishes a count of resistant organisms imported by them. What exists is the screening rule, the outbreak investigations, and the reference laboratory referrals that started the subject.