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Interferon-gamma (IFN-g) is a pro-inflammatory cytokine that plays a pivotal role in the defense mechanism against Brucella infection. It was hypothesized that the IFN-g in (þ874 A/T in intron 1) TT and þ5644 T/A, TT genotypes, which are reportedly associated with high IFN production, are associated with susceptibility to brucellosis in Iranian subjects. Genotyping of these IFN-g variants by an allele-specific polymerase chain reaction method was performed in 281 subjects, comprising 153 patients with active brucellosis and 128 healthy controls. It was found that the þ874 minor allele (A) and homozygote genotype (AA) were significantly more frequently present in brucellosis patients than in controls (OR ¼ 2.588; 95% CI, 1.313-5.104; P ¼ 0.006 for the AA genotype; OR ¼ 1.575; 95% CI, 1.124-2.216; P ¼ 0.010 for the A allele). However, the allelic and genotypic distribution of the IFN-g polymorphism at position UTR5644 A>T did not differ significantly between patients and controls (P > 0.05). The distribution of haplotypes in this study suggests that the T/A haplotype (þ874/ UTR5644), which was present more frequently in controls than in patients, may protect subjects against Brucella infection. It is suggested that IFN-g þ874 AA genotype and A allele are risk factors for developing brucellosis infection in Iranian subjects.

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KEYWORDS ABSTRACTBrucella melitensis; Brucella abortus; Persister cell; TA systems; Real-time PCR Scan to discover online Background & Objective: Persister cells are defined as a subpopulation of bacteria that are capable of reducing their metabolism and switching to dormancy in stress conditions. Persister cells formation has been attributed to numerous mechanisms, including stringent response and Toxin-Antitoxin (TA) systems. This study aimed to investigate the hypothetical role of TA systems in persister cells formation of Brucella strains by evaluating toxins of type II TA systems (RelE, Fic, Brn T, cogT) expression.Methods: Brucella strains treated with a lethal dose of gentamicin and ampicillin and to determine the number of surviving cells, bacterial colonies were counted at different time intervals. The role of TA systems in persister cell formation was then determined by toxin expression levels using qRT-PCR method. Results:Our results showed the viability of persister cells after 7 h. The results of relative qRT-PCR showed higher levels of toxin gene expression due to stress conditions, suggesting the possible role of TA systems in persister cells formation and antibiotics tolerance. Conclusion:The results of this study showed that considering the importance of persistence and the tolerance to antibiotics, further studies on persister cells formation and related genes such as the TA system genes in Brucella strains might help us to identify the precise mechanisms leading to persister cells formation. Main Subjects:Microbiology

Our findings indicate that in the DU group, the serum concentrations of IL-12 but not of IL-13 were influenced by bacterial CagA, independent of the VacA status, suggesting that high IL-12 levels may contribute to susceptibility to DU in CagA-positive individuals. These findings could possibly be considered to improve the predictive or prognostic values of inflammatory cytokines for DU, and also to design possible novel therapeutic approaches.

The IL-18 - 607C variant was associated with higher levels of serum IL-18 and an increased risk of DU. Moreover, our findings indicated that serum concentrations of IL-18 were influenced by CagA factor, irrespective of the VacA status, suggesting that high levels of IL-18 in CagA-positive subjects predisposes to susceptibility to DU.

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