Multilocus sequence typing and antimicrobial resistance in Enterococcus faecium isolates from fresh produce

• Published in: Antonie van Leeuwenhoek 2014-02, Vol.105 (2), p.413-421
• Main Authors: Burgos, Mª José Grande, Aguayo, Mª Carmen López, Pulido, Rubén Pérez, Gálvez, Antonio, López, Rosario Lucas
• Format: Article
• Language: English
• Subjects: Agricultural commodities; ampicillin; Anti-Bacterial Agents - pharmacology; Antibiotic resistance; benzalkonium chloride; biguanides; Biocides; Biomedical and Life Sciences; cefotaxime; chlorhexidine; Disinfectants - pharmacology; Drug resistance; Drug Resistance, Bacterial; Enterococcus faecium; Enterococcus faecium - classification; Enterococcus faecium - drug effects; Enterococcus faecium - genetics; Enterococcus faecium - isolation & purification; fresh produce; hexachlorophene; imipenem; Life Sciences; Medical Microbiology; Microbial Sensitivity Tests; Microbiology; Multilocus Sequence Typing; Plant Sciences; Short Communication; Soil Science & Conservation; vancomycin; Vegetables - microbiology
• ISSN: 0003-6072; 1572-9699
• DOI: 10.1007/s10482-013-0073-4

The purpose of the present study was to determine the relatedness of Enterococcus faecium isolates from fresh produce to E. faecium strains from other sources by using multi-locus sequence typing (MLST) and to determine the antimicrobial resistance of the isolates. MLST analysis of 22 E. faecium isolates from fresh produce revealed 7 different sequence types (ST 22, ST 26, ST 43, ST 46, ST 55, ST 94 and ST 296). Most isolates belonged to ST 296 (40.9 %), followed by ST 94 (27.3 %). All isolates were sensitive to vancomycin and to imipenem, and only one was resistant to ampicillin (MIC 32 mg/l). However, all were resistant to cefotaxime and ceftazidine. E. faecium isolates from fresh produce were inhibited by quaternary compounds (benzalkonium chloride, cetrimide, hexadecylpyridinium chloride, didecyldimethylammonium bromide), biguanides (chlorhexidine), polyguanides [poly-(hexamethylene guanidinium) hydrochloride], bisphenols (triclosan, hexachlorophene) and biocidal solutions of P3 oxonia and P3 topax 66. Didecyldimethylammonium bromide and triclosan were the least effective biocides in growth inhibition, while hexadecylpyridinium chloride was the most effective. Results from MLST typing and antibiotic resistance suggest that the studied E. faecium isolates from fresh produce are not related to the clinically-relevant clonal complex CC17.