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- Whole-genome sequencing analysis of Shiga toxin-producing Escherichia coli O22:H8 isolated from cattle prediction pathogenesis and colonization factors and position in STEC universe phylogeny
- Wanderson Marques Da Silva , Mariano Larzabal , Flavia Figueira Aburjaile , Nahuel Riviere , Luisina Martorelli , James Bono , Ariel Amadio , Angel Cataldi
- J. Microbiol. 2022;60(7):689-704. Published online June 22, 2022
- DOI: https://doi.org/10.1007/s12275-022-1616-z
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- 5 Citations
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Abstract
- Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen capable of causing illness in humans. In a previous study, our group showed that a STEC isolate belonging to O22:H8 serotype (strain 154) can interfere with STEC O157:H7 colonization both in vitro and in vivo. Using whole-genome sequencing and genomic comparative, we predicted a subset of genes acquired by O22:H8 strain 154 through horizontal gene transfer that might be responsible for the phenotype previously described by our group. Among them were identified genes related to the pathogenesis of non-LEE (locus of enterocyte effacement) STEC, specific metabolic processes, antibiotic resistance and genes encoding for the T6SS-1 that is related to inter-bacterial competition. In addition, we showed that this strain carries stx1c and stx2dact, a mucus-inducible variant. The results obtained in this study provide insights into STEC genomic plasticity and the importance of genomic islands in the adaptation and pathogenesis of this pathogen.
- Lipocalin2 as a potential antibacterial drug against Acinetobacter baumannii infection
- Daejin Lim , Su-Jin Park , Ha Young Kim , Minsang Shin , Miryoung Song
- J. Microbiol. 2022;60(4):444-449. Published online March 28, 2022
- DOI: https://doi.org/10.1007/s12275-022-2007-1
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- 3 Citations
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Abstract
- Available antibiotics to treat Acinetobacter baumannii infection is limited due to increasing resistance and the emergence of multiple drug-resistant strains. Hence, discovering effective agents against A. baumannii to reduce the number of infectionrelated deaths is imperative. In search of novel and alternative antibiotics, the antibacterial function of lipocalin2 (Lcn2) was investigated to treat systemic infections of A. baumannii using a mouse neutropenia model. We observed a significant increase in serum Lcn2 levels upon bacterial injection into the mouse, and the administration of recombinant Lcn2 (rmLcn2) extended their survival. Such protective effects were also observed in rmLcn2-pretreated macrophages, where rmLcn2 reduced the survival of the pathogen inside the macrophages. The underlying molecular mechanism of Lcn2 protection was also investigated. We observed that pretreatment of the Raw- 264.7 macrophages with rmLcn2 markedly altered the expression of tonB3, which encodes a component of the transporter for ferrisiderophores in A. baumannii. However, the expression of katG, the gene encoding catalase, remained unaffected. These indicate that Lcn2-mediated defense against the pathogen is related to nutritional immunity rather than reactive oxygen species (ROS) production. Furthermore, the addition of rmLcn2 in infected mice diminished bacterial burden in multiple organs and enhanced the expression of tonB3 in the liver, spleen, and lungs of the infected mice. Increased survival rate due to rmLcn2 treatment declined when the infection model was established using lcn2-defective (lcn2-/-) mice, which indicated the necessity of endogenous Lcn2. Therefore, the antibacterial function of Lcn2 can be exploited to develop an alternative therapeutic agent against A. baumannii.
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