Extensively Drug-Resistant Carbapenemase-Producing Pseudomonas aeruginosa and Medical Tourism from the United States to Mexico, 2018–2019

Ian Kracalik; D. Cal Ham; Gillian McAllister; Amanda R. Smith; Maureen Vowles; Kelly Kauber; Melba Zambrano; Gretchen Rodriguez; Kelley Garner; Kaitlyn Chorbi; P. Maureen Cassidy; Shannon McBee; Rhett J. Stoney; Kathleen Moser; Margarita E. Villarino; Oscar E. Zazueta; Amelia Bhatnagar; Erisa Sula; Richard A. Stanton; Allison C. Brown; Alison L. Halpin; Lauren Epstein; Maroya Spalding Walters


Emerging Infectious Diseases. 2022;28(1):51-61. 

In This Article

Abstract and Introduction


Carbapenem-resistant Pseudomonas aeruginosa (CRPA) producing the Verona integron–encoded metallo-β-lactamase (VIM) are highly antimicrobial drug-resistant pathogens that are uncommon in the United States. We investigated the source of VIM-CRPA among US medical tourists who underwent bariatric surgery in Tijuana, Mexico. Cases were defined as isolation of VIM-CRPA or CRPA from a patient who had an elective invasive medical procedure in Mexico during January 2018–December 2019 and within 45 days before specimen collection. Whole-genome sequencing of isolates was performed. Thirty-eight case-patients were identified in 18 states; 31 were operated on by surgeon 1, most frequently at facility A (27/31 patients). Whole-genome sequencing identified isolates linked to surgeon 1 were closely related and distinct from isolates linked to other surgeons in Tijuana. Facility A closed in March 2019. US patients and providers should acknowledge the risk for colonization or infection after medical tourism with highly drug-resistant pathogens uncommon in the United States.


In the United States, 20% of Pseudomonas aeruginosa from adult device–associated healthcare-associated infections and 9% from surgical site infections are not susceptible to carbapenem antimicrobial drugs.[1] However, only 1%–3% of carbapenem-resistant P. aeruginosa isolates harbor carbapenemases,[2] enzymes typically encoded on mobile genetic elements that can be shared horizontally between bacteria and inactivate carbapenems and most other β-lactam antimicrobial drugs. These enzymes include active-on-imipenem (IMP) and Verona integron-encoded metallo-β-lactamase (VIM). These carbapenem-resistant P. aeruginosa (CP-CRPA) are associated with multidrug-resistant (MDR) phenotypes and can rapidly spread in healthcare settings because of poor infection prevention and control practices.[2–7] Acquiring CP-CRPA is typically associated with receipt of healthcare; in the United States, cases have been linked to travel and domestic outbreaks.[8,9] Carbapenemase-producing organisms might emerge in new geographic regions from inpatients who previously received healthcare in regions in which these organisms are more common.[10–12]

VIM is the most commonly identified carbapenemase in P. aeruginosa worldwide.[13] It is also the most common carbapenemase identified in P. aeruginosa in the United States, although the absolute number of cases remains low. During 2017–2018, ≈200 VIM-CRPA were identified among nearly 15,000 isolates tested nationally (https://arpsp.cdc.gov/profile/arln/crpa).

Annually, up to 750,000 US residents participate in medical tourism, defined as international travel for the purpose of receiving medical care.[14,15] Motivations for medical tourism often include lower cost, shorter wait times, and fewer medical requirements.[15,16] Among medical tourists surveyed in 11 US states and territories during 2016, Mexico was the most common destination country.[16] The exact number of US medical tourists who undergo bariatric surgery annually is unknown, but in a 2017 survey, 10 Mexico-based bariatric surgeons reported performing >2,500 procedures on medical tourists, most of whom were US residents.[17] One study estimated 2% of bariatric surgeries worldwide are performed on medical tourists; most of them were performed in Mexico.[17]

Several infectious disease outbreaks linked to medical tourism have been reported, including nontuberculous mycobacteria surgical site infections among medical tourists from the United States and Switzerland undergoing cosmetic surgery in Latin America[18,19] and Q fever among US medical tourists receiving live cell therapy in Germany.[20] In this report, we describe an outbreak of extensively drug-resistant (XDR) P. aeruginosa harboring bla VIM (VIM-CRPA) among US medical tourists who underwent bariatric surgery in Tijuana, Mexico, during 2018–2019.