The Battle between Bacteria and Bacteriophages: A Conundrum to Their Immune System.

Bacteria and their predators, bacteriophages, or phages are continuously engaged in an arms race for their survival using various defense strategies. Several studies indicated that the bacterial immune arsenal towards phage is quite diverse and uses different components of the host machinery. Most studied antiphage systems are associated with phages, whose genomic matter is double-stranded-DNA. These defense mechanisms are mainly related to either the host or phage-derived proteins and other associated structures and biomolecules. Some of these strategies include DNA restriction-modification (R-M), spontaneous mutations, blocking of phage receptors, production of competitive inhibitors and extracellular matrix which prevent the entry of phage DNA into the host cytoplasm, assembly interference, abortive infection, toxin-antitoxin systems, bacterial retrons, and secondary metabolite-based replication interference. On the contrary, phages develop anti-phage resistance defense mechanisms in consortium with each of these bacterial phage resistance strategies with small fitness cost. These mechanisms allow phages to undergo their replication safely inside their bacterial host's cytoplasm and be able to produce viable, competent, and immunologically endured progeny virions for the next generation. In this review, we highlight the major bacterial defense systems developed against their predators and some of the phage counterstrategies and suggest potential research directions.

Hepatitis C virus infection in Jeddah city, Saudi Arabia: Seroprevalence and knowledge.

The infection rate of the hepatitis C virus (HCV) in Saudi Arabia is among the lowest in the world. However, it is likely that poor knowledge and awareness of HCV infection could minimize the effectiveness of prevention and control programs in the kingdom. Thus, the study objective was to estimate the prevalence of HCV infection, and to assess current knowledge about it, in the targeted population. Data on 5482 Saudi people attending primary healthcare centers in Jeddah City in 2014/2015 were analyzed in this cross-sectional study. Questions that covered the natural history, risk behavior, and prevention, and treatment of HCV were collected using a predesigned questionnaire. HCV seroprevalence was assessed using an enzyme-linked immunosorbent assay. HCV prevalence of 0.38% (95% confidence interval: 0.22-0.54) was found. The level of knowledge of the natural history, risk behavior, and prevention and treatment of HCV was poor among the participants. The lowest level of knowledge for all participants pertained to its prevention and treatment. The prevalence of HCV was low in Saudi Arabia (0.38%). However, adequate knowledge of HCV was lacking. Thus, the need to increase knowledge and awareness of HCV in the Saudi population is warranted.