ESBL Genes of E. coli in Chicken Meat and Humans | CDC EID

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Volume 17, Number 7–July 2011
Research
Extended-Spectrum β-Lactamase Genes of Escherichia coli in Chicken Meat and Humans, the Netherlands

Ilse Overdevest, Ina Willemsen, Martine Rijnsburger, Andrew Eustace, Li Xu, Peter Hawkey, Max Heck, Paul Savelkoul, Christina Vandenbroucke-Grauls, Kim van der Zwaluw, Xander Huijsdens, and Jan Kluytmans Author affiliations: St. Elisabeth Hospital, Tilburg, the Netherlands (I. Overdevest, J. Kluytmans); Amphia Hospital, Breda, the Netherlands (I. Overdevest, I. Willemsen, J. Kluytmans); University Medical Centre, Amsterdam, the Netherlands (M. Rijnsburger, P. Savelkoul, C. Vandenbroucke-Grauls, J. Kluytmans); Heart of England National Health Service Foundation Trust, Birmingham, UK (A. Eustace, L. Xu, P. Hawkey); University of Birmingham, Birmingham (P. Hawkey); and National Institute of Public Health and Environmental Protection, Bilthoven, the Netherlands (M. Heck, K. van der Zwaluw, X. Hiujsdens)

Suggested citation for this article


Abstract
We determined the prevalence and characteristics of extended-spectrum β-lactamase (ESBL) genes of Enterobacteriaceae in retail chicken meat and humans in the Netherlands. Raw meat samples were obtained, and simultaneous cross-sectional surveys of fecal carriage were performed in 4 hospitals in the same area. Human blood cultures from these hospitals that contained ESBL genes were included. A high prevalence of ESBL genes was found in chicken meat (79.8%). Genetic analysis showed that the predominant ESBL genes in chicken meat and human rectal swab specimens were identical. These genes were also frequently found in human blood culture isolates. Typing results of Escherichia coli strains showed a high degree of similarity with strains from meat and humans. These findings suggest that the abundant presence of ESBL genes in the food chain may have a profound effect on future treatment options for a wide range of infections caused by gram-negative bacteria.

Infections with drug-resistant bacteria are associated with higher rates of illnesses and deaths, which have a serious effect on costs of health care (1,2). During the past decade, drug resistance in Enterobacteriaceae has increased dramatically worldwide. This increase has been caused mainly by an increased prevalence of extended-spectrum β-lactamase (ESBL)–producing Enterobacteriaceae (3,4) and has increased the use of last-resort antimicrobial drugs (i.e., carbapenems).

ESBL genes are located on plasmids that can be easily transferred between and within bacterial species. Some ESBL genes are mutant derivatives of established plasmid-mediated β-lactamases (e.g., blaTEM/SHV), and others are mobilized from environmental bacteria (e.g., blaCTX-M). During the 1990s, most reports on ESBL genes concerned blaTEM/SHV types, which were related to cross-infections in hospitals. However, the recent global increase has been caused mainly by blaCTX-M–type genes. The epidemiology of ESBL genes is changing rapidly and shows marked geographic differences in distribution of genotypes of blaCTX-M β-lactamases (5). In the United States, the most prevalent drug resistance gene in humans is currently blaCTX-M-15, which is often associated with a widely distributed variant of Escherichia coli O:25b, sequence type 131 (ST131). Bacteria containing ESBL genes are currently a common cause of infections originating in community-dwelling persons without a history of hospitalization, and these organisms can then be introduced into hospitals (6–9).

Fecal carriage of ESBL genes has been identified as the major reservoir in the environment, but the original source of this colonization has not been clearly identified. Because bacterial species that carry ESBL genes are normal inhabitants of the gastrointestinal tract, food is a potential source of them. The presence of ESBL genes has been clearly documented in food-production animals, especially chickens (10,11). Drug resistance in animals is caused mainly by the large amount of antimicrobial drugs used in food production. In addition to their presence in farm animals, ESBL genes have been found in retail meat (12,13). A recent survey of broiler chickens in Great Britain found that blaCTX-M-1 was the most prevalent ESBL gene (14). Although ESBL genes in food-production animals pose a potential threat to humans, Randall et al. concluded that drug resistance genes in chickens (blaCTX-M-1) differed from the drug resistance genes most frequently found in humans (blaCTX-M-15) (14).

In the Netherlands, use of antimicrobial drugs and associated drug resistance in humans is among the lowest in Europe (15). Paradoxally, use of antimicrobial drugs in food-production animals in this country is among the highest in Europe (16). Therefore, the Netherlands provides a good setting to monitor spread of drug resistance from an animal reservoir into the human population. This spread was recently exemplified by emergence of livestock-associated methicillin-resistant Staphylococcus aureus in pigs and veal calves. This was first reported in the Netherlands in 2004 and has now been reported worldwide (17). The aim of our study was to determine the prevalence of ESBL genes in retail meat and hospitalized patients in the Netherlands and to compare ESBL genes and bacterial strains involved.

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ESBL Genes of E. coli in Chicken Meat and Humans CDC EID


Suggested Citation for this Article
Overdevest I, Willemsen I, Rijnsburger M, Eustace A, Xu L, Hawkey P, et al. Extended-spectrum β-lactamase genes of Escherichia coli in chicken meat and humans, the Netherlands. Emerg Infect Dis [serial on the Internet]. 2011 Jul [date cited]. http://www.cdc.gov/EID/content/17/7/1216.htm

DOI: 10.3201/eid1707.110209

Comments to the Authors
Please use the form below to submit correspondence to the authors or contact them at the following address:
Jan Kluytmans, Laboratory for Microbiology and Infection Control, Amphia Hospital, PO Box 90158, 4800 RK Breda, the Netherlands; email: jankluytmans@gmail.com