A foodborne source is one route being investigated as part of an increase of E. coli in Europe.

Between 2017 and 2019, the National Reference Centre for multidrug-resistant gram-negative bacteria and German health officials detected an increase in oxacillinase-244 (OXA-244)-producing E. coli.

European authorities said the increase in cases of a difficult-to-detect carbapenemase (OXA-244) in a species such as E. coli that causes community-acquired infections is of concern. They added there is a risk transmission in the community may contribute to the loss of carbapenems as options for treating serious E. coli infections in Europe.

The source and route of transmission of OXA-244-producing E. coli in Europe and the U.K. is unclear.

Increase of cases since 2013
A European Centre for Disease Prevention and Control (ECDC) spokeswoman said it is likely that several routes of transmission have a role in the increase.

“Transmission via food is just one hypothesis that is currently being considered in the context of OXA-244-producing E. coli in Europe. We lack evidence of foodborne origin, such as isolation from foodstuff of OXA-244-producing E. coli isolates with a tight genomic relationship with human isolates, or common exposure to a certain product by people with OXA-244-producing E. coli in various regions of Europe,” she told Food Safety News.

EU data showed that 33 cases of OXA-244-producing E. coli were detected between 2013 and 2015, followed by 31 in 2016, 21 in 2017, 83 in 2018 and 116 in 2019. However, use of whole genome sequencing (WGS) may have led to more discriminatory identification of cases from samples and contributed to the increase, according to officials.

WGS data identified one main, geographically dispersed cluster of E. coli sequence type 38 with the blaOXA244 gene present in countries that had submitted data. These are Denmark, Finland, France, Germany, Ireland, Luxembourg, the Netherlands, Norway, Sweden and the United Kingdom. Most cases in this cluster were detected in 2018 and 2019.

The first isolates detected in the Netherlands and U.K. were from 2013. One was from this year. An increase in OXA-244-producing E. coli ST38 has also been noted in Switzerland.

An overlap in time and place was found for a few cases in Germany, indicating possible person-to-person transmission. Healthcare-associated clusters were not seen and transmission in healthcare settings cannot explain the distribution in 10 nations and different regions within countries without linked hospital networks.

Food possibility needs investigation
Transmission via food of animal or non-animal origin, by contact with the environment or direct contact with animals, is possible, according to ECDC.

However, no OXA-244-producing E. coli isolates from food or animal sources have been identified in Europe. Imported food or animal products from regions where OXA-48-like carbapenemases are endemic or food from domestic sources could be a contributing factor.

E. coli ST38 isolates that did not carry the blaOXA244 gene have been found in meat, fowl and humans in Germany, and retail chicken in Norway, with related isolates also in humans. In a study in the United States, meat was shown to be a possible source for community-acquired urinary tract infections caused by E. coli, with ST38 a common sequence type in humans and retail meat.

ECDC said given potential public health implications, the possibility of food and animal products contaminated with OXA-244 producing E. coli being distributed over a large geographical area requires investigation. Further studies are needed to determine if the environment, crops, animals and foods contaminated with OXA-244-producing E. coli contributed to the outbreak.

Information about travel was available for only a few cases but Turkey and Egypt were commonly reported previous destinations or countries of hospitalization.

E. coli ST38 often carries genes encoding for extended-spectrum-beta-lactamases (ESBLs).

The ECDC spokeswoman said most patients seem to either only be carriers, so asymptomatic in terms of OXA-244-producing E. coli, or have urinary tract infections.

“Regarding the incubation period, it is known that multidrug-resistant organisms such as OXA-244-producing E. coli may persist as part of the intestinal flora for months. Infection, especially urinary tract infections, can occur from this source at any point during carriage. The incubation period may therefore be extremely variable, which also complicates the epidemiological investigations as exposure and transmission may occur long before infection or detection.”

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