Our data complement the findings that genotype D viruses are prevalent in the Turkish population. Being rapid and inexpensive, restriction enzyme analysis described in this study should be useful for large-scale epidemiological analysis of HBV infections.

Objectives: Staphylococcus aureus (S. aureus) is one of the major human pathogens in both community acquired and nosocomial infections. Heavy increase of antibiotic resistance between S. aureus strains became an important public health problem in progress of time. In this study, the antimicrobial effects of piceatannol on S. aureus growth was investigated. Patients and Methods: The antimicrobial effect of piceatannol on a standard S. aureus (DSMZ 6148) strain and two clinical S. aureus strains (C1 and C2) was tested in vitro at concentrations between 0 and 750 µg/ mL. Tigecycline and gentamicin were used as positive controls. For each strain, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values of piceatannol and the control antibiotics were determined separately using the broth microdilution method according to CLSI (Clinical and Laboratory Standards Institute) standards at 24 and 48 h. Results: After 24 and 48 h of treatment with piceatannol, the average MIC for all tested strains was 283 µg/mL and 383 µg/mL, respectively. Bactericidal activity increased as piceatannol concentration increased for one of the three strains. After 24 and 48 h of treatment with piceatannol, the average MBC for all strains was 717 µg/ mL and 583 µg/ mL, respectively. The S. aureus strains were found to be susceptible to tigecycline and gentamicin. Conclusion: Piceatannol has antimicrobial effect against S. aureus; however, more data regarding the effects of this compound on other microorganisms and its bioavailability are needed.

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The frequency of infections caused by Staphylococcus aureus strains and the rate of antibiotic resistance among these strains are gradually increasing. Accordingly, serious problems emerge in the treatment of community or hospital acquired S.aureus infections. This study was aimed to determine the role of MIC and sub-MIC concentrations of gentamicin on biofilm and coagulase forming effects of S.aureus in in vitro test systems and cell cultures. A standard S.aureus ATCC 25923 strain and two clinical S.aureus strains isolated from blood cultures (C1 and C2) were included in the study. Gentamicin MIC values of the strains were determined with microdilution method at the cation-adjusted Mueller Hinton broth according to CLSI standards. For each strain, MIC, 50% MIC and 25% MIC values of gentamicin were determined separately. At the determined MIC values, biofilm formations of strains were determined with crystal violet method spectrophotometrically. Also, coagulase activities of the strains were evaluated in glass tubes. Human origin epithelial cell cultures namely HEp-2 cell lines, were infected with the standard and clinical S.aureus strains (Multiplicity of infection: 50/1) and left for incubation for two hours. After all, MIC, 50% MIC and 25% MIC values of gentamicin, were added to infected cell lines and incubated for 18 hours. Cells were blown up with distilled water and then bacteria were collected. Biofilm formation and coagulase production of these bacteria were evaluated. When S.aureus ATCC 25923 strain and C1 strains' biofilm formation was evaluated before (in vitro) and after incubation in cell culture, no difference was observed. However in C2 strain, under the effect of MIC level gentamicin, biofilm formation was occurred after interaction with the cell. In the same way, when coagulase responses were evaluated, after interaction with the cell, coagulase production of C2 strain was inhibited. These results indicated that, phenotypic characteristics such as biofilm formation and coagulase production might change during the process of bacterial adaptation to microenvironment. Further advanced experimental modelling designed with different combinations of antibiotics and different cell lines may provide data about the causes and timing of these phenotypic changes and shed light on the development of new treatment policies.

Staphylococcus aureus colonized in the nose of healthcare workers is an important risk factor for the development of hospital-acquired staphylococcal infections. Cross-contamination of this bacterium between the hands of healthcare workers and the surfaces they contact is known. In this study, we aimed to evaluate the clonal relationship between eight S. aureus strains isolated from the nose of healthcare providers and five S. aureus strains isolated from mobile phones carried by healthcare providers. Methods: The clonal relationship between the strains and molecular epidemiological status were investigated by the pulsed-field gel electrophoresis (PFGE) method. Results: The first and third strains are isolated from the mobile phone and the nose of a healthcare provider working in the intensive care unit were the same. The second and fourth strains were isolated from the mobile phone and nose of another healthcare provider working in the intensive care unit were the same. The fifth strain, which was found to be the same as the second and fourth strains, was isolated from the mobile phone of another healthcare provider working in the intensive care unit. No similarity was observed between the other strains. Conclusion: Our findings indicate that S. aureus strains colonized in the nose of healthcare workers are also transmitted to other surfaces and that the hospital environment and co-used devices pose a risk for spread. For this reason, training of healthcare workers on the infection control procedure, hand hygiene, environmental disinfection and regular cleaning of mobile phones are important components in order to prevent hospital-acquired infections.