The incidence of virulence factors among 48 Enterococcus faecium and 47 Enterococcus faecalis strains from foods and their antibiotic susceptibility were investigated. No strain was resistant to all antibiotics, and for some strains, multiple resistances were observed. Of E. faecium strains, 10.4% were positive for one or more virulence determinants, compared to 78.7% of E. faecalis strains. Strains exhibiting virulence traits were not necessarily positive for all traits; thus, the incidence of virulence factors may be considered to be strain specific.Enterococci constitute a major component of the microflora of artisanal cheeses produced in southern Europe (10) and are considered to play an important role in ripening and aroma development (1,5,28). This has led to the suggestion that enterococci be included in starter culture preparations for the manufacture of certain Mediterranean cheeses (1,5,23). However, enterococci are also major nosocomial pathogens causing a variety of infections (19,20). Enterococcus faecalis strains clearly dominate among enterococci isolated from human infections, while Enterococcus faecium strains are associated with the majority of the remainder (15).A specific cause for concern and contributing factor to pathogenesis of enterococci is their resistance to a wide variety of antibiotics (18,20). However, antibiotic resistance as such cannot explain the virulence of enterococci. Although enterococci possess subtle virulence traits (25), considerable progress has recently been made in determining these. For example, studies have shown that phenotypes such as ␤-hemolysin/bacteriocin (also called cytolysin) and aggregation substance (AS), which are encoded by E. faecalis pheromone-responsive plasmids, are related to pathogenicity and enhance the virulence of enterococci in animal models (2,12,14,15,26). AS is an adhesin which mediates the formation of cell clumps that allow the highly efficient transfer of the sex pheromone plasmid on which AS is encoded (4). An interesting variation in the generally similar AS (about 90% homology) encoded by sex pheromone plasmids such as pAD1, pCF10, and pPD1 is encoded by asa373 on plasmid pAM373. This AS is also involved in a clumping response, but it has little homology to the "classical" AS and therefore represents a rather unique type of adhesin (22). Other virulence factors include the adhesin called enterococcal surface protein (Esp) and gelatinase (Gel), which is an extracellular metalloendopeptidase (26).This study aimed to determine the incidence of hemolysin; classical AS; and the aggregation substances Asa373, Gel, and Esp and antibiotic susceptibility among enterococci isolated mostly from cheeses. Studies formed part of the European Union (EU) project FAIR-CT97-3078, "Enterococci in Food Fermentations: Functional and Safety Aspects." As E. faecalis and E. faecium are predominantly associated with human infection and as these species were also predominant among strains isolated from cheese in the EU study, our study was concerned only with...

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Aims: To identify enterococci from Hussuwa, a Sudanese fermented sorghum product, and determine their technological properties and safety for possible inclusion in a starter culture preparation. Methods and Results: Twenty-two Enterococcus isolates from Hussuwa were identified as Enterococcus faecium by using phenotypic and genotypic tests such as 16S rDNA gene sequencing, RAPD-PCR and restriction fragment length polymorphism of the 16S/23S intergenic spacer region fingerprinting. Genotyping revealed that strains were not clonally related and exhibited a considerable degree of genomic diversity. Some strains possessed useful technological properties such as production of bacteriocins and H 2 O 2 or utilization of raffinose and stachyose. None produced a-amylase or tannase. A safety investigation revealed that all strains were susceptible to the antibiotics ampicillin, gentamicin, chloramphenicol, tetracycline and streptomycin, but some were resistant to ciprofloxacin, erythromycin, penicillin and vancomycin. Production of biogenic amines or presence of genes encoding virulence determinants occurred in some strains. Conclusions: Enterococcus faecium strains are associated with fermentation of Sudanese Hussuwa. Some strains exhibited useful technological properties such as production of antimicrobial agents and fermentation of indigestible sugars, which may aid in stabilizing and improving the digestibility of the product respectively. Significance and Impact of the Study: Enterococci were shown to play a role in the fermentation of African foods. While beneficial properties of these bacteria are indicated, their presence in this food may also imply a hygienic risk as a result of antimicrobial resistances or presence of virulence determinants.

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Lactobacillus plantarum CNRZ 1228 exhibited heme-dependent catalase activity under environmental conditions similar to those encountered during sausage fermentation. The 1,455-bp catalase gene (katL) was cloned and encoded a protein of 484 amino acids. Expression of katL in a heterologous host showed that katL encodes a functional catalase. PCR screening of selected strains of lactic acid bacteria for katL indicated the presence of similar genes in other strains of lactobacilli.