Findings suggest that IFN-γ (+874), IRF-1 (-410, -388), and IFNGR-1 (-56, -611) are candidate gene markers for determining patient susceptibility to the development of chronic hepatitis B and C.

Hepatitis A is a widespread infectious disease. The prevalence of the disease is closely related to socioeconomic status (SES) and environmental factors. Understanding its prevalence is essential for instituting appropriate precautions. The aim of this study was to determine the prevalence of hepatitis A and evaluate the associated demographic features in children and young adults in Istanbul. In total, 630 individuals between the ages of 5-24 were included in the study. They were classified into four age groups (5-9, 10-14, 15-19 and 20-24 years). The seropositivity of hepatitis A in the whole study population was 40%. Age-specific prevalence was 11.4% in children 5-9 years old, 29% in those 10-14 years old, 49.7% in those 15-19 years old and 69% in those 20-25 years old. Seropositivity was associated with increasing age, low SES, large family size, low maternal educational level, use of unsafe drinking water and living in regions with poor infrastructure and incomplete urbanization. When we compared our results with previous seroprevalence studies performed in Istanbul, we found an epidemiological shift towards increasing age. Factors associated with changes in prevalence were urbanization and associated infrastructure improvement, knowledge of the disease by the population, use of good hygiene and use of vaccination in those at high risk.

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Panton-Valentine leukocidin (PVL) is an important virulence determinant of Staphylococcus aureus. The aim of this study was to investigate the prevalence of PVL genes in clinical S. aureus isolates and to determine the staphylococcal chromosomal cassette mec (SCCmec) types of methicillin-resistant S. aureus (MRSA) strains obtained from inpatients and outpatients of two hospitals in Turkey. Of the 304 S. aureus strains (230 hospital acquired [HA] and 74 community-onset [CO]), 261 were MRSA and 43 were methicillin-sensitive S. aureus (MSSA). PVL positivity was determined in 12 (1 HA and 11 community acquired) strains. Eight were MRSA, and four were MSSA. Seven of the PVL-positive strains were isolated from wound specimens, four from urine, and one from synovial fluid. SCCmec type III (93.78%) was more prevalent among HA-MRSA strains, and SCCmec type IIIB (41.18%) was more prevalent among CO-MRSA strains. Pulsed-field gel electrophoresis patterns of the PVL-positive isolates were different. Our results indicate that PVL-positive strains are able to cause infection in nearly every system without the need for additional risk factors. Our PVL-positive CO-MRSA strains carry SCCmec types other than types IV and V. Due to the presence of PVL-positive strains in the hospitals, it is important to establish appropriate infection control measures to prevent their spread in the community and in hospitals.

The incidence of drug-resistant pathogens differs greatly between countries according to differences in the usage of antibiotics. The purpose of this study was to investigate the phenotypic resistance of 321 methicillin resistance Staphylococcus aureus (MRSA) and 195 methicillin susceptible S. aureus (MSSA) in a total of 516 S. aureus strains to macrolide, lincosamide, streptogramin B (MLS B ), ketolid, and linezolid. Disk diffusion method was applied to determine MLS B phenotype and susceptibility to different antibiotic agents. It was found that 54.6% of the isolates were resistant to erythromycin (ERSA), 48% to clindamycin, 55% to azithromycin, 58.7% to spiramycin, 34.7% to telithromycin, and 0.4% to quinupristin-dalfopristin, respectively. No strain resistant to linezolid was found. The prevalence of constitutive (cMLS B ), inducible (IMLS B ), and macrolides and type B streptogramins (M/MS B ) among ERSA isolates (237 MRSA, 45 MSSA) was 69.6 %, 18.2%, and 12.2 % in MRSA and 28.9%, 40%, and 31.1% in MSSA, respectively. In conclusions, the prevalence of cMLS B was predominant in MRSA; while in MSSA strains, iMLS B and M/MS B phenotype were more higher than cMLS B phenotype resistance. The resistance to quinupristindalfopristin was very low, and linezolid was considered as the most effective antibiotic against all S.aureus strains.