Does International Travel Spread Antimicrobial-Resistant Bacteria?

Antimicrobial-resistant bacteria may be spread through traveler contamination at international airports, according to research published in Clinical Microbiology and Infection.¹

Frieder Schaumburg, MD, of the Institute of Medical Microbiology at the University Hospital Münster in Münster, Germany, and colleagues conducted a cross-sectional study of international travelers to determine the types of antimicrobial-resistant bacteria that are trafficked through airports and the global spread of those bacteria.

“Airports are important travel hubs where people are exposed to pathogens that are carried by others,” Dr Schaumburg and colleagues wrote. “It seems plausible that drug-resistant bacteria from an individual traveler could be transferred to inanimate surfaces and then picked up by others.”

Toilet door handles—one of the last places people often touch before washing their hands—were chosen due to their frequent use by multiple people after “potentially unhygienic activities” (eg, using the restroom) and because they are typically contaminated with skin and gut flora.

Over the course of the study, members of Dr Schaumburg’s research team swabbed 400 toilet door handles (60.5% men’s and 39.5% women’s restrooms) in 136 airports in 59 countries around the world while they were traveling; 80.75% of swabs were taken in arrival airports, 2.75% were taken at a layover airport, and 16.5% were taken at the destination airport. Each door handle was swabbed with a moistened environmental swab (3M™ Quick Swab) and stored in a Letheen neutralizing buffer (3M™) for a median of 7 days before undergoing laboratory analysis.

Staphylococcus aureus, Stenotrophomonas maltophilia, and Acinetobacter baumannii complex were the 3 most commonly identified bacteria (5.5%, 2%, and 1.3%, respectively); S aureus was most frequently found in Africa, followed by South America, Europe, North America, and Asia (7.7%, 6.5%, 5.5%, 4.7%, and 4.6%, respectively). Pseudomonas aeruginosa, vancyomycin-resistant enterococci, and extended spectrum β-lactamase-producing Enterobacteriaceae were not detected. The remaining samples consisted of staphylococci, enterococci, and other Gram-negative rods (Citrobacter and Enterobacter sp).

The researchers then conducted further analysis on the isolated bacteria to determine their antimicrobial resistance. Methicillin-susceptible S aureus was most commonly resistant against penicillin (42.9%), followed by erythromycin/clindamycin (9.5%), and levofloxacin (4.8%). Five A baumannii complex isolates were found to be susceptible to quinolones and gentamicin; 2 S maltophilia istolates were resistant to trimethoprim/sulfamethoxazole. No phenotypic carbapenem resistance or carbapenemase-encoding genes were detected among A baumannii and enterobacteriaceae samples.

One methicillin-resistant S aureus (MRSA, mecA-positive, ST672, T1451, SCCmec type V, PVL-negative)—an emerging, community-associated MRSA clone from the Indian subcontinent—was swabbed in Paris; researchers found that it was resistant to animoglycosides, quinolones, macrolides, clindamycin, and trimethoprim/sufamethoxazole but susceptible to glycopeptides, linesolid, and rifampicin.

“Almost every geographic region has its problems with antimicrobial resistance, which are not limited to MRSA,” said Dr Schaumburg in a press release. “These challenges are not restricted to industrialized regions. A joint strategy that brings together low-, middle-, and high-income countries is probably the most important aspect in the fight against antimicrobial resistance.”²

Study Limitations

• Researchers were unable to quantify the door handle confirmation, and were unable to immediately culture the swabs immediately after sampling due to logistic constraints
• It is unknown if or how door handles were disinfected prior to sampling
• Handle material was unavailable to the researchers
• Sources of bias may explain both over- and under-estimation of the true rate of contamination. 

References

1. Schaumburg F, Köck R, Leendertz FH, Becker K. Airport door handles and the global spread of antimicrobial-resistant bacteria: a cross sectional study. Clin Microbiol Infect. 2016;22(12):1010-1011. doi: 10.1016/j.cmi.2016.09.010
2. Airport door handles: Are they helping to spread drug-resistant bacteria around the world? [news release]. Basel, Switzerland: European Society of Clinical Microbiology and Infectious Diseases. Accessed November 30, 2016.