The role of temperate bacteriophages in bacterial infection

Bacteriophages are viruses that infect bacteria. There are an estimated 1031 phage on the planet, making them the most abundant form of life. We are rapidly approaching the centenary of their identification, and yet still have only a limited understanding of their role in the ecology and evolution of bacterial populations. Temperate prophage carriage is often associated with increased bacterial virulence. The rise in use of technologies, such as genome sequencing and transcriptomics, has highlighted more subtle ways in which prophages contribute to pathogenicity. This review discusses the current knowledge of the multifaceted effects that phage can exert on their hosts and how this may contribute to bacterial adaptation during infection

Using assessment of higher brain functions of children with GJB2-associated deafness and cochlear implants as a procedure to evaluate language development

Objective: While investigators have reported that patients with GJB2-associated deafness and cochlear implants have preferable language development, the mechanisms of this phenomenon remains unknown. The goat of the present study was to assess higher brain functions of patients with GJB2-retated and GJB2-unrelated deafness as a method of evaluating language development. Methods: Eight children with cochlear implants were subjected to genetic testing for GJB2 and underwent the Raven colored progressive matrices test, Rey's auditory verbal learning test, Rey's complex figure test, the standardized Language test for aphasia, the picture vocabulary test, and the standardized comprehension test for abstract words. Results:Three children were diagnosed with GJB2-related deafness, and five children were diagnosed with GJB2-unrelated deafness. All three GJB2-related cases demonstrated normal range higher brain functions and fair language development. By contrast, one GJB2-unrelated case showed a semantic disorder, another demonstrated a visual cognitive disorder with dyslexia, and another had attention deficit-hyperactivity disorder. Conclusions:Children with GJB2-unrelated deafness showed a high frequency of heterogeneous disorders that can affect proper language development. This difference between children with GJB2-retated and GJB2-unrelated deafness may account for the improved language development in children with GJB2-related deafness and cochlear implants. Further, genetic diagnosis of the non-syndromic hearing toss represents a useful tool for the preoperative prediction of outcomes following a cochlear implant procedure.</p

Diverse Temperate Bacteriophage Carriage in Clostridium difficile 027 Strains

The hypervirulent Clostridium difficile ribotype 027 can be classified into subtypes, but it unknown if these differ in terms of severity of C. difficile infection (CDI). Genomic studies of C. difficile 027 strains have established that they are rich in mobile genetic elements including prophages. This study combined physiological studies, electron microscopy analysis and molecular biology to determine the potential role of temperate bacteriophages in disease and diversity of C. difficile 027.We induced prophages from 91 clinical C. difficile 027 isolates and used transmission electron microscopy and pulsed-field gel electrophoresis to characterise the bacteriophages present. We established a correlation between phage morphology and subtype. Morphologically distinct tailed bacteriophages belonging to Myoviridae and Siphoviridae were identified in 63 and three isolates, respectively. Dual phage carriage was observed in four isolates. In addition, there were inducible phage tail-like particles (PT-LPs) in all isolates. The capacity of two antibiotics mitomycin C and norfloxacin to induce prophages was compared and it was shown that they induced specific prophages from C. difficile isolates. A PCR assay targeting the capsid gene of the myoviruses was designed to examine molecular diversity of C. difficile myoviruses. Phylogenetic analysis of the capsid gene sequences from eight ribotypes showed that all sequences found in the ribotype 027 isolates were identical and distinct from other C. difficile ribotypes and other bacteria species.A diverse set of temperate bacteriophages are associated with C. difficile 027. The observed correlation between phage carriage and the subtypes suggests that temperate bacteriophages contribute to the diversity of C. difficile 027 and may play a role in severity of disease associated with this ribotype. The capsid gene can be used as a tool to identify C. difficile myoviruses present within bacterial genomes