gms | German Medical Science

Negligence of safe food handling, particularly beef and lamb, among the majority of the Iranian population causes high frequencies of chronic disease, including food-related diarrhea [1]. Meat contaminated with Escherichia coli O157H7 ranks among the most severe food-related diarrheal diseases [2]. However, a less pathogenic, but epidemiologically relevant intestinal pathogen is Enterococcus faecalis, which lives commensally in both human and animal intestinal tracts. If food is handled inappropriately, contamination of food products may be the consequence [3]. During the past few years, food products contaminated with vancomycin-resistant enterococci (VRE) have been reported worldwide, and are responsible for morbidity and mortality among hospitalized patients or those receiving systemic antibiotic treatment [3]. To date, no study exists on the prevalence of E.coli O157H7 and E. faecalis in meat in Iran. Therefore, a pilot study was conducted to analyze the prevalence of both index organisms in ground meat.

To investigate the presence or absence of E. coli O157H7 and/or E. faecalis in meat, 24 samples of ground, not cooked meat were collected in 14 “kebab” restaurants in Ilam, Iran. Additionally, 10 samples of raw meat were obtained and screened. Index organisms were identified by conventional microbiological methods and biochemical tests. If E. faecalis was found, minimal inhibitory concentration to vancomycin was determined following CLSI recommendations. Additionally, a vanA-specific PCR was performed to verify vancomycin-resistant enterococci (VRE) strains.

While a few previously conducted studies [4], [5] reported on the presence of E. coli O157H7 without detecting VRE, the present investigation found the opposite result. Although we observed no E. coli O157H7 strains among 24 ground meat samples, E. faecalis was obtained from all 24 samples of ground, cooked kebab meat and 10 raw meat samples. Furthermore, all E. faecalis isolates showed resistance to vancomycin, with 5 strains also showing the presence of the vanA gene in the plasmid [6] of E. faecalis isolates (Figure 1 [Fig. 1]). This is the first report of VRE presence in ground meat in Iran.

To date, most studies have considered E. coli O157H7 as the most important pathogenic microorganism in ground meat in Iran [1], [2]. Surprisingly, none of the ground meat samples investigated in this study was contaminated by E. coli O157H7, whereas E. faecalis, including VRE, was found in ground meat in Iran. This study is the first study reporting on E. faecalis, and particularly VRE, in ground meat in Iran.

Because E. faecalis is a constituent of the gut microflora in animals and humans [3] with a close association between humans and farm animals, enterococci were identified as contaminants in meat [3], [7]. The occurrence of 5 positive vanA genes in E. faecalis isolates are of particular interest, since VRE is associated with nosocomial infections. Although kebab in Iran is well cooked, the presence of E. faecalis and VRE in our tested ground meat is of epidemiological interest.

Our observation warrants further epidemiologic investigation and should be studied in greater depth in the future. Furthermore, restaurants should be monitored more closely to control critical bacteria in animal products, especially in ground meat.

The authors declare that they have no competing interests.