Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Acinetobacter baumannii among horses entering a veterinary teaching hospital: The contemporary "Trojan Horse"

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From: PLoS ONE(Vol. 13, Issue 1)
Publisher: Public Library of Science
Document Type: Report
Length: 4,920 words
Lexile Measure: 1550L

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Author(s): Birgit Walther 1,2,*, Katja-Sophia Klein 3, Ann-Kristin Barton 3, Torsten Semmler 4, Charlotte Huber 2, Silver Anthony Wolf 4, Karsten Tedin 1, Roswitha Merle 5, Franziska Mitrach 6, Sebastian Guenther 7,8, Antina Lübke-Becker 1, Heidrun Gehlen 3


Multi-drug resistant (MDR) pathogens, especially extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae, have frequently been reported as a cause of severe infections in horses, which has become an issue of increasing importance in veterinary infection control and biosafety in equine clinical settings [1-6]. While there is no significant clinical difference for individual horses with respect to the particular pathogen source in case of infection, the distinction between an endogenous self-infection versus an exogenous cross-infection is crucial from the standpoint of epidemiology and disease prevention (http://www.who.int/water_sanitation_health). Thus, precise information on the local endemic load and epidemiology of MDR carried by patients entering a hospital is crucial for infection control policies [7]. Such data can be used for the targeted development of prevention strategies to protect the horse from exogenous as well as endogenous infection sources [3]. In the past, severe infections with Gram-negative bacteria in hospitalized horses have generally been reported in association with Salmonella infections [8-10] and ESBL-producing Enterobacteriaceae [3,11]. Moreover, equine patients colonized or infected with Acinetobacter baumannii [12,13] might pose a risk for themselves or other patients within a clinical environment. Consequently, the aim of this study was to determine the carriage rate of these pathogens which harbor the potential for nosocomial and zoonotic transmission in equine clinical settings as a first step for subsequent implementation of more specific hygiene barriers. Accordingly, ESBL-producing Enterobacteriaceae, Salmonella and A . baumannii were selected as indicator pathogens to estimate the influx of Gram-negative MDR strains.

Material and methods

Participants, setting and sample collection

As part of a hygiene intervention program, a prospective prevalence study was conducted at the clinic for horses at the Freie Universität Berlin with sampling taking place over a two-year period, from April to October in 2014 and again in 2015. Horses showing clinical signs associated with either "colic" or an "open wound" at hospital admission were included. Inclusion criteria for patient samples were as follows: sterile cotton swabs with Amies transport medium (Mast Diagnostica, Reinfeld) of both anterior nostrils taken on arrival without delay and faecal samples of the first defecation after admission within 120 min. Horses leaving the clinic within 24h after admission were excluded from the study groups. Those horses which did not survive 24h due to euthanasia or sudden death were included, since these animals were regarded as fully hospitalized.

In addition, a wound swab was taken immediately upon admission from the "open wound" patients within the reception area. One person (K-S.K.) was trained to take the microbiological samples and collected the data on horse patients during both study periods.


According to the German regulations for research with animal subjects, taking swabs from anterior nasal cavity of equine patients at hospital admission in the context of a hygiene evaluation does not require approval (Landesamt für Gesundheit und Soziales, Berlin,...

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Gale Document Number: GALE|A525648536