The purpose of this in vitro study was to evaluate the antibacterial activity of five different root-canal sealers (RoekoSeal, Ketac-Endo, AH Plus, Sealapex, Sultan). With the use of Enterococcus faecalis as a test organism, both the agar-diffusion test (ADT) and direct-contact test (DCT) were performed. For DCT, sealers were mixed and placed on the sidewall of microtiter plate wells. A 10-microl bacterial suspension was placed on the tested material samples. Bacteria were allowed to directly contact to the sealers for 1 h at 37 degrees C. Bacterial growth was then spectrophotometrically measured through every 30 min for 19 h by using an Anthos Labtec HT 2. For ADT, a 200-microl bacterial suspension was spread on brain-heart infusion agar plates. Freshly mixed sealers were poured into uniform wells punched in the agar. After periods of incubation at 37 degrees C for 24 h and 7 days in humid atmosphere, the zones of inhibition of bacterial growth on agar plates were observed and measured. Ketac-Endo, Sultan, and AH Plus had similar results for DCT. These sealers were more potent bacterial-growth inhibitors than Sealapex and RoekoSeal. According to ADT, RoekoSeal showed no antibacterial activity. There was no significant difference among AH Plus, Sealapex, and Sultan (p > 0.05). Ketac-Endo demonstrated lower antimicrobial activity than these sealers (p < 0.05). Time had no effect on the antibacterial activity of the tested sealers (p > 0.05). The antibacterial efficiency of the materials varied according to the tests used. It was concluded that the technique, time, and ingredients of the tested material can affect the results of the microbiological studies.

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The aim of this study was to investigate the presence of Staphylococcus aureus and staphylococcal enterotoxin (SE) genes in Urfa cheese samples and to characterize the enterotoxigenic potential of these isolates. From a total of 127 Urfa cheese samples, 53 isolates (from 41.7% of the samples) were identified by a species-specific PCR assay as S. aureus. Of these isolates, 40 (75.5%) gave positive PCR results for the 3' end of the coa gene. The coa-positive S. aureus strains were characterized for their population levels and enterotoxigenic properties, including slime factor, β-lactamase, antibiotic susceptibilities, production of the classical SEs (SEA through SEE), in both cheese and liquid cultures by enzyme-linked immunosorbent assay (ELISA) and for the presence of specific genes, including classical SE genes (sea through see), mecA, femA, and spa, by PCR. The genetic relatedness among the coa-positive S. aureus isolates was investigated by PCR-based restriction fragment length polymorphism (RFLP) analysis and the 23S rRNA gene spacer. The 23S rRNA gene spacer and coa RFLP analysis using AluI and Hin6I revealed 14 different patterns. SEB, SEC, and SEA and SEE were detected by ELISA in three cheese samples. Fourteen S. aureus strains harbored enterotoxin genes sea through see, and three strains carried multiple toxin genes. The most commonly detected toxin gene was sec (25% of tested strains). Of the 40 analyzed S. aureus strains, 3 (7.5%) were mecA positive. Based on tandem repeats, four coa and spa types were identified. The results of this study indicate that S. aureus and SEs are present at significant levels in Urfa cheese. These toxins can cause staphylococcal food poisoning, creating a serious hazard for public health.