Purpose. In vitro analyses of virulence, pathogenicity and associated host cell responses are important components in the study of biofilm infections. The Candida-related infection, denture-associated oral candidosis, affects up to 60 % of denture wearers and manifests as inflammation of palatal tissues contacting the denture-fitting surface. Commercially available three-dimensional tissue models can be used to study infection, but their use is limited for many academic research institutions, primarily because of the substantial purchase costs. The aim of this study was to develop and evaluate the use of in vitro tissue models to assess infections by biofilms on acrylic surfaces through tissue damage and Candida albicans virulence gene expression.
Methodology. In vitro models were compared against commercially available tissue equivalents (keratinocyte-only, SkinEthic; full-thickness, MatTek Corporation). An in vitro keratinocyte-only tissue was produced using a cancer-derived cell line, TR146, and a full-thickness model incorporating primary fibroblasts and immortalised normal oral keratinocytes was also generated. The in vitro full-thickness tissues incorporated keratinocytes and fibroblasts, and have potential for future further development and analysis.
Results. Following polymicrobial infection with biofilms on acrylic surfaces, both in-house developed models were shown to provide equivalent results to the SkinEthic and MatTek models in terms of tissue damage: a significant (P<0.05) increase in LDH activity for mixed species biofilms compared to uninfected control, and no significant difference (P>0.05) in the expression of most C. albicans virulence genes when comparing tissue models of the same type.
Conclusion. Our results confirm the feasibility and suitability of using these alternative in vitro tissue models for such analyses.
Purpose. Shigellosis is one of the most important food-borne and water-borne diseases worldwide. Although antibiotics are considered as efficient agents for shigellosis treatment, improper use of these has led to the emergence of antibiotic-resistant Shigella spp. Therefore, finding a new strategy as alternative treatment seems necessary.
Methodology. Different samples from a wastewater treatment plant were used to isolate Shigella spp. specific phages. Physiological properties were determined, and genomic analysis was also carried out.
Results. A virulent Siphoviridae bacteriophage, vB_SsoS-ISF002, was isolated from urban wastewater in Iran and showed infectivity to different isolates of both Shigella sonnei and Shigella flexneri. vB_SsoS-ISF002 was stable at different pH values and temperatures. It had a short latent period (15 min), a large burst size (76±9 p.f.u. cell−1) and appropriate lytic activity especially at high MOI. Its genome (dsDNA) was 50 564 bp with 45.53 % GC content and 76 predicted open reading frames. According to comparative genomic analysis and phylogenic tree construction, vB_SsoS-ISF002 was considered as a member of the T1virus genus.
Conclusion. These results indicated that vB_SsoS-ISF002 is a novel virulent T1virus phage and may have potential as an alternative treatment for shigellosis.
Human respiratory syncytial virus causes severe lower respiratory tract infection in neonates and children. Genotype ON1, with duplication of 72-nt in the G gene, was first detected in Canada and then recorded in other countries. In the current study, we describe the first detection of the ON1 genotype among children in Egypt in 2014/2015. Sequence analysis of the full-attachment G gene revealed that the majority of the strains examined were related to the ON1 genotype and only one sample related to N1 genotype. The Egyptian ON1 strains showed unique non-silent mutations in addition to variable mutations near the antigenic sites in comparison to the original ON1 ancestor strain. Continuous surveillance of hRSV regionally and globally is needed to understand the evolutionary mechanisms and strategies adopted by hRSV and their inducers for better adaption to the host.