Antibacterial effect of N-acetylcysteine and taurolidine on planktonic and biofilm forms of Enterococcus faecalis.

AIM: This study investigated the antimicrobial activity of taurolidine and N-acetylcysteine (NAC) on planktonic and biofilm Enterococcus faecalis phenotypes. MATERIALS AND METHODS: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of NAC and taurolidine were determined using broth microdilution, utilizing calcium hydroxide (CH), sodium hypochlorite, and chlorhexidine for comparisons. Thereafter, the ability of dentin powder to neutralize the antibacterial activity of NAC and taurolidine was studied. The efficacy of both antimicrobial agents on E. faecalis biofilms was examined quantitatively by exposure of 21-day-old E. faecalis biofilms on dentin disks. The cytotoxicity of human dental pulp fibroblast cells in contact with the extracts was evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assay. RESULTS: The MIC and MBC of NAC, taurolidine, and CH were not affected by pre-incubation in dentin powder. As verified by qualitative assay of E. faecalis biofilms, CH was the strongest bactericidal agent at all test dilutions, regardless of the presence of dentin powder. The antibacterial effect of NAC and taurolidine was significantly lower than that of CH at all test dilutions. At 48 h, all test agents showed similar, but high levels of cytotoxicity. CONCLUSION: NAC and taurolidine were effective against E. faecalis in planktonic state, at the expense of demonstrating cytotoxic effects. For both planktonic and biofilm forms of E. faecalis, neither NAC nor taurolidine offered any advantage over CH.

[Determination of hepatitis C virus genotypes among hepatitis C patients in Eastern Black Sea Region, Turkey]. / Dogu Karadeniz Bölgesi Hepatit C Hastalarinda Hepatit C Virusu Genotiplerinin Belirlenmesi.

Hepatitis C virus (HCV), the major cause of transfusion-associated hepatitis, is an important public health problem in the world as well as in Turkey. HCV is grouped as six distinct genotypes and a large number of closely-related subtypes. Genotyping of HCV is an important tool for providing epidemiological data, prediction of prognosis, and optimization of antiviral therapy. This study was carried out to determine the distribution of HCV genotypes in hepatitis C patients residing in different provinces of the Eastern Black Sea Region, Turkey. A total of 304 HCV-RNA positive cases (151 male, 153 female; age range: 11-93 years, mean age: 55.2 ± 13.3 years) who were admitted to the Molecular Microbiology Unit of Department of Medical Microbiology, Karadeniz Technical University Faculty of Medicine, between January 2009 to December 2012, were included in the study. HCV genotypes were detected in plasma samples of the patients by using commercial assays [INNO-LiPA HCV II (Innogenetics, Belgium) or Abbott RealTime HCV Genotype II (Abbott Molecular Inc, USA)]. Due to the ambiguous genotyping results in some samples with these methods, an in-house multiplex polymerase chain reaction (PCR) assay with genotype-specific primers was also used in the study. Similar to the previous reports from Turkey, our results showed that four HCV genotypes (1, 2, 3, and 4) prevailed in the Eastern Black Sea Region and the predominant genotype and subtype were genotype 1 (92.8%) and 1b (87.5%), respectively. Distribution of genotypes were observed to vary according to the province. Prevalences of subtype 1a, genotype 2, 3, and 4 were noted as 5.3%, 1.6%, 4.9%, and 0.7%, respectively. Furthermore, the samples from Giresun, Gumushane and Bayburt provinces, which are relatively less immigrated, had higher genotype 1, and the prevalence rates in the region was affected by the presence of non-citizen residents. This study is the first report on distribution of HCV genotypes in chronic hepatitis C patients living in the provinces of Eastern Black Sea Region. Moreover, genotype-specific multiplex PCR assay could be useful in resolving certain methodological problems such as "ghost bands" encountered in line probe assay (LiPA) and multiple genotypes (including genotype 4) observed in real-time PCR during the characterization of HCV genotypes seen in Turkey.