Antibiotic resistance and virulence genes in Enterococcus species isolated from raw and processed seafood.

This study evaluated the antibiotic resistance characteristics and virulence genes of enterococci isolated from raw and processed seafood sold in the Marmara Region, Turkey. In this context, the enterococcal load was determined as between 1.0 and 2.5 log CFU/g in 39 of a total of 397 samples. It was determined that 117 strains isolated from the samples belonged to Enterococcus gallinarum, E. casseliflavus, E. durans, E. faecium, and E. faecalis species. Erythromycin, tetracycline, streptomycin, and gentamicin resistance was observed, whereas the tetM, ermB, aac(6')-aph(2'')-la genes were found in a majority of the isolates. It was also determined that the isolates carried the agg2 and gelE virulence genes. When all these results are evaluated, the presence of these isolates in aquatic products may pose a risk in terms of food safety and public health.

Seasonal variations and human health risk assessment of trace elements in the bivalve ecosystem in the Sea of Marmara.

Twelve trace elements were studied in four economically important bivalve molluscs (Mediterranean mussel, manila clam, striped venus clam, and truncated wedge clam) from the southern Marmara Sea for seasonal bioaccumulation and human health risk assessment. According to the findings, Fe and Zn were the most accumulative and element concentrations changed considerably (P < 0.05) between seasons and species. Daily, weekly, monthly intake and target hazard quotients of the trace elements were estimated and compared with maximum limits. The results revealed that consuming these bivalve molluscs from the southern Marmara Sea could be considered safe for human consumption. Nevertheless, further monitoring is needed in order to better follow the development in time of elemental pollution due to increasing environmental pressure on the Marmara Sea basin, together with research on other different bioaccumulative organisms.

Bacteriological quality, heavy metal and antibiotic resistance in Sapanca Lake, Turkey.

Sapanca Lake is important as a source of drinking water. In this study, we aimed to detect the bacterial quality, the frequency of bacterial antibiotic and heavy metal resistance, and bioindicator bacteria in the water samples taken from Sapanca Lake in the period between 2008 and 2010. The resistance of bacterial isolates to certain antibiotics and heavy metal salts was investigated using disc diffusion and minimum inhibitory concentration techniques. Bacterial metabolic reactions were tested using the VITEK 2 Compact 30 micro identification system for identification of cultivable bacteria. Twenty-seven bacteria species belonging to three classes-Gammaproteobacteria, Bacilli, Flavobacteria-were recorded for the first time in Sapanca Lake. The highest indicator bacteria were recorded as 71 ± 3.1 × 104 CFU/100 ml in the summer season. The highest bacterial resistance was recorded as 90.47% against vancomycin in a total of 84 strains. Ampicillin (88.10%) and amoxicillin-clavulanate (64.29%) followed them. The resistance varied between 10.71 and 59.52% against cefuroxime, kanamycin, aztreonam, ceftazidime, cefotaxime, and oxacillin. The highest frequency against heavy metal salts was recorded as 74.19% against NiCl2. The heavy metal resistance against Cu, Zn, Hg, and Cd detected as 52.38%, 46.42%, 33.33%, and 26.19%, respectively. The results showed that the occurrence of heavy metals and antibiotic sources in Sapanca Lake induced a tolerance in bacteria for the metal salts and antibiotic derivatives tested. The fluctuations in the indicator bacteria and the occurrence of pathogenic bacteria also showed the possibility that the coastal areas of Sapanca Lake had been exposed to contamination due to inadequate sewage treatment.

Seasonal abundance and diversity of culturable heterotrophic bacteria in relation to environmental factors in the Gulf of Antalya, Eastern Mediterranean, Turkey.

The abundance of culturable heterotropic bacteria studied on and according to depth levels and seasons in the Gulf of Antalya. Environmental factors were compared regarding culturable heterotrophic bacteria abundance and diversities of bacteria. During the study period (between August 2009 and April 2010, seasonally in the Gulf of Antalya, at six stations and six depth levels (0-20 cm, 10, 25, 50, 100, 200 m). The bacterial isolates were identified in the automated micro identification system VITEK 2 Compact 30 (Biomereux, France). The mean abundance was higher in Sts. D, E and F than Sts. A, B and C, located in the eastern part of the gulf. The mean abundance decreased as the depth level increased. The mean abundance of CHB ranged between 8.15 × 10(6) and 2.54 × 10(8) CFU ml(-1) throughout the year. Abundance of CHB differed according to the variations of biotic and abiotic factors. A total of 27 taxa of bacteria including six bacterial classes were reported in this study as the first records for the Gulf of Antalya. Six bacterial classes: Gamma Proteobacteria (46.81 %), Bacilli (27.66 %), Beta Proteobacteria (12.77 %), Alfa Proteobacteria (6.38 %), Actinobacteria (4.26 %) and Flavobacteria (2.13 %) were determined. The study resulted in increased knowledge on the composition and biochemical response of bacteria isolated from eutrophic and oligotrophic areas. 23 bacteria species belonging to 16 families were reported.

Depuration Times of Donax trunculus and Tapes decussatus.

The present study was performed to determine the depuration time and ability of Donax trunculus (Wedge Clam) and Tapes decussatus (Carpet Shell) contaminated with Escherichia coli, Salmonella enterica subsp. enterica serovar Typhimurium and Vibrio parahaemolyticus. Clams were contaminated with each bacterium at the level of 7.0 - 8.0 Log10 cfu/g. After contamination, clams were analyzed every 3 h in the first 24 h time period and every 6 h until the 72nd hour. During the depuration process of both clams, the level of bacteria decreased quickly to 40% of initial load in the first 12 h. The results of this study indicate that the depuration time of carpet shells for all bacteria is 66 h. The depuration process of the wedge clam was different from the carpet shell; S. typhimurium and E. coli can be depurated in 66 and 78 h, respectively, while V. parahaemolyticus was present after 72 h at the level of 1.7 Log10 cfu/g.

Depuration Times of Donax trunculus and Tapes decussatus

The present study was performed to determine the depuration time and ability of Donax trunculus (Wedge Clam) and Tapes decussatus (Carpet Shell) contaminated with Escherichia coli, Salmonella enterica subsp. enterica serovar Typhimurium and Vibrio parahaemolyticus. Clams were contaminated with each bacterium at the level of 7.0 - 8.0 Log10 cfu/g. After contamination, clams were analyzed every 3 h in the first 24 h time period and every 6 h until the 72nd hour. During the depuration process of both clams, the level of bacteria decreased quickly to 40% of initial load in the first 12 h. The results of this study indicate that the depuration time of carpet shells for all bacteria is 66 h. The depuration process of the wedge clam was different from the carpet shell; S. typhimurium and E. coli can be depurated in 66 and 78 h, respectively, while V. parahaemolyticus was present after 72 h at the level of 1.7 Log10 cfu/g.

The occurrence of pathogenic bacteria in some ships' ballast water incoming from various marine regions to the Sea of Marmara, Turkey.

The composition and frequency of antibiotic resistance of pathogenic bacteria, the abundance of heterotrophic aerobic bacteria (HPC) and possible in-situ use of chromogenic agar were investigated in the ships' ballast water coming from different regions of the world to the Sea of Marmara, Turkey for the first time. The samples that were taken from 21 unit ships coming from various marine environments of the Southern China Sea, the Atlantic Ocean, the Mediterranean and the Black Sea to the Sea of Marmara, Turkey in 2009 and 2010 were tested. 38 bacteria species, 27 of them pathogenic bacteria belonging to 17 familia, were detected. Vibrio cholera was not detected in the samples. However, the presence of a high number of HPC, including a cocktail of pathogenic bacteria showed that the ships carry a potential risk for the Sea of Marmara.