Prevalence of ESBL-producing Enterobacteriaceae (ESBLE) in Raw Vegetables

Abstract number: O102

Reuland E.A., al Naiemi N., Rijnsburger M.C., Savelkoul P.H., Vandenbroucke-Grauls C.M.

Introduction: Recent data show that ESBL-producing bacteria are found in Dutch soil samples (Knapp et al., Environ. Sci. Technol. 2010), and in food-producing animals such as broiler chickens and pork meat. We wondered whether ESBL-E are also present in raw vegetables.

Objectives: The aim of this study was to evaluate the presence of ESBL-E in raw vegetables in the region of Amsterdam.

Materials and Methods: Between October 14 and November 29, 2010, samples of 17 different types of vegetables were obtained from the market, and from organic and conventional stores in the region of Amsterdam. We focused on vegetables that grow on and in the ground. Screening for ESBL-E was performed with a selective enrichment broth and inoculation on a selective screening agar, containing cefotaxime and ceftazidime. ESBL production was confirmed with the double disc synergy test with clavulanic acid. Species identification and further antibiotic susceptibility testing were performed with the Vitek-2 system (bioMérieux). DNA-isolation was performed with the QIAamp DNA mini kit (Qiagen). ESBL genes were characterized by microarray (Check-KPC ESBL Check-Points).

Results: Out of 79 analyzed samples, four yielded ESBL-producing Enterobacteriaceae (5%). ESBL-E were found in parsnip, bean sprouts and radish; this means that three (17,6%) of the vegetables types were contaminated with ESBL-E. Of the four positive samples, three were from vegetables of organic origin. The ESBL-producing strains were Enterobacter cloacae (in two samples), Citrobacter freundii (in one sample) and Klebsiella pneumoniae (in one sample). Three strains were positive in the microarray for CTX-M ESBL belonging to the CTX-M-1 family and one for an SHV ESBL. PCR and sequencing are pending.

Conclusion: Our results document the presence of ESBL-producing Enterobacteriaceae in some raw vegetables obtained in Amsterdam, the Netherlands, implying that raw vegetables may be a source of resistance genes. The possible impact of our findings on human health highlights the need to further evaluate the presence of ESBL-E in raw vegetables and to explore whether colonization of the human gut from this source does occur.

Session Details

Date: 07/05/2011
Time: 00:00-00:00
Session name: Abstracts of 21st ECCMID / 27th ICC
Location: Milan, Italy, 7 - 10 May 2011
Presentation type:
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