Travel Patterns Spark C auris Outbreaks in NY and NJ

Increased travel and migration are likely associated with recent outbreaks of Candida auris in the United States, based on data from a study of simulated travel patterns.

The spread of resistant C auris has become a significant public health issue, with both simultaneous and independent outbreaks occurring worldwide, and travel patterns may play a role, wrote Rita R. Verma, PhD, of New York Medical College, Valhalla, New York, and colleagues.

New York City remains a hub for international travelers and currently has the highest prevalence of C auris clade I, which originated in South Asia, they wrote.

“The study is an offshoot of our decade-long focus on the first emergence and subsequent spread of Candida auris in New York-New Jersey area,” said corresponding author Vishnu Chaturvedi, MD, of New York Medical College, in an interview. “Interestingly, four major genotypes of this fungal pathogen arose independently from East Asia, South Asia, South America, and South Africa,” he said.

The genotypes were clustered in different regions of the United States, and the researchers conducted a modeling study to explain these patterns.

In the study, published in Microbiology Spectrum, the researchers created a simulation using data from four elements: Travel to the United States from South Asia, the proportion of the US population in New York and New Jersey, the proportion of hospitals in New York and New Jersey, and the proportion of all travelers entering the United States through New York and New Jersey.

“The process for collecting input data from various sources proved arduous, but we were pleasantly surprised to find the simulation supported our initial hypothesis about travel-related origins from South Asia and the initial spread in New York-New Jersey,” Chaturvedi told Medscape Medical News.

Public health authorities reported 56 cases of C auris in the New York-New Jersey area compared to seven cases in the rest of the United States overall between 2013 and 2016. The researchers analyzed cases of C auris clade I documented between 2015 and 2017 and associations with South Asian travel, population, number of hospitals, and all travel.

Based on an X2 goodness-of-fit test, using Monte Carlo simulation, the researchers found that the proportion of travelers from South Asia was significantly associated with patterns of C auris clade I cases in the New York-New Jersey area.

“In contrast, the simulation revealed that, while not perfect, using the number of travelers originating in South Asia to predict introductions was more consistent with observations than total population or number of hospitals in an area,” the researchers wrote in the study.

The findings were limited by several factors including the fact that the origin of an international flight to the United States is not always the origin of the traveler, nor is the entry point to the United States the traveler’s final destination in the United States, the researchers noted. However, simulations suggest a link between travel patterns and increased C auris in the New York-New Jersey area, they said.

Takeaways and Next Steps

The knowledge about biogeography of C auris and epidemiology of C auris candidiasis continues to evolve, said Chaturvedi. “For patient care, it appears prudent to probe the history of travel and exposure and get laboratory data on identification and antifungal drug susceptibility of C auris from the patient,” he said. More detailed whole-genome sequencing of C auris, is needed, as is surveillance in high-risk settings and enhanced antifungal stewardship, in order to improve infection control and public health, he added.

“Whole genome characterization of all New York-New Jersey C auris remains a top priority,” Chaturvedi told Medscape Medical News. “Frontline clinical laboratories need more refined laboratory tests for rapid identification and characterization of C auris,” he said. In addition, continuing medical education is needed to help physicians make evidence-based decisions for patient care to improve outcomes, he noted.

Keep Tabs on Pathogen Travel Patterns

C auris is a significant public health concern; the fungus can cause both invasive infections and asymptomatic colonization that spreads easily, said Shirin A. Mazumder, MD, associate professor and infectious disease specialist at The University of Tennessee Health Science Center, Memphis, Tennessee, in an interview.

“C auris can be difficult to treat because it may be resistant to many different antifungal medications,” said Mazumder, who was not involved in the current study. Evaluating the role of geography is important for a better understanding of the disease and how to prevent transmission, she said.

Data from other infectious diseases have shown that travel facilitates the introduction of pathogens across geographic boundaries, so the findings of the current study linked travel to the emergency of C auris in the United States were not surprising, Mazumder told Medscape Medical News.

“At this point, C auris has been detected in many countries across 5 continents,” she said. Counsel patients to adhere to good infection prevention practices, she emphasized. “One of the most effective ways to prevent C auris infection includes frequently washing hands with soap and water or using an alcohol-based hand sanitizer,” Mazumder added.

As for clinical implications of the findings, evaluation of domestic and local spread of C auris may be useful in future studies to increase understanding not only of disease transmission but also of how to decrease the spread of infection, Mazumder said.

This study was supported by the Centers for Disease Control and Prevention-Antibiotic Resistance Lab Network and the National Institutes of Health. The researchers had no financial conflicts to disclose. Mazumder had no financial conflicts to disclose.