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Background: The Brazilian endemic clone Pseudomonas aeruginosa ST277 carries important antibiotic resistance determinants, highlighting the gene coding for SPM-1 carbapenemase. However, the resistance and persistence of this clone is apparently restricted to the Brazilian territory. To understand the differences between Brazilian strains from those isolated in other countries, we performed a phylogenetic analysis of 47 P. aeruginosa ST277 genomes as well as analyzed the virulence and resistance gene profiles. Furthermore, we evaluated the distribution of genomic islands and assessed in detail the characteristics of the CRISPR-Cas immunity system in these isolates., Results: The Brazilian genomes presented a typical set of resistance and virulence determinants, genomic islands and a high frequency of the CRISPR-Cas system type I-C. Even though the ST277 genomes are closely related, the phylogenetic analysis showed that the Brazilian strains share a great number of exclusively SNPs when compared to other ST277 genomes. We also observed a standard CRISPR spacers content for P. aeruginosa ST277, confirming a strong link between sequence type and spacer acquisition. Most CRISPR spacer targets were phage sequences., Conclusions: Based on our findings, P. aeruginosa ST277 strains circulating in Brazil characteristically acquired In163 and PAGI-25, which can distinguish them from strains that do not accumulate resistance mechanisms and can be found on the Asian, European and North American continents. The distinctive genetic elements accumulated in Brazilian samples can contribute to the resistance, pathogenicity and transmission success that characterize the ST277 in this country.

Objectives: Klebsiella pneumoniae carbapenemase (KPC) is the most widespread carbapenemase in Enterobacteriaceae in Brazil. Although its presence is not common in Pseudomonas aeruginosa, it has been increasingly reported. Here we report a draft genome sequence of a KPC-producing P. aeruginosa strain recovered from a bloodstream infection sample in Brazil., Methods: The antimicrobial susceptibility of KPC-producing P. aeruginosa CCBH17348 was evaluated by the disk diffusion method, Etest and broth microdilution. Carbapenemase production was confirmed by colorimetric assay (Carba NP) and PCR. Genomic DNA was sequenced by Illumina MiSeq sequencing and was assembled using the A5-Miseq pipeline, and gene annotation was performed using RAST 2.0. The database ResFinder 2.1, CRISPRFinder and MLST website were used to identify resistance genes, clustered regularly interspaced short palindromic repeats (CRISPRs) and sequence types (STs), respectively., Results: Isolate CCBH17348 was considered multidrug-resistant, was susceptible to fluoroquinolones, gentamicin and polymyxin, and belonged to a newly described ST (ST2584), carrying an IncQ1 plasmid with bla KPC-2 and aph(3')-VI genes. Other genes associated with resistance and virulence found in the genome were bla OXA-50 , bla PAO , fosA, catB, mutation in oprD and mexT (MexEF-OprN efflux regulator), and exotoxin-encoding genes (exoS, exoY and exoT)., Conclusions: This study highlights the potential risk of new STs of P. aeruginosa carrying bla KPC-2 and the potential spread of bla KPC-2 in an IncQ1 plasmid., (Copyright © 2018 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.)

In this study, we describe the genetic features of an XDR KPC-2-producing Klebsiella pneumoniae isolate by using whole-genome sequencing, its clinical-epidemiological context and susceptibility against antimicrobial combinations. The isolate belongs to clonal complex 258 and harbors several acquired genes and mutations associated with antimicrobial resistance., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Acinetobacter baumannii is an important pathogen frequently associated with nosocomial outbreaks around the world. In Brazil, A. baumannii has become particularly problematic because of its prevalence and the carbapenems resistance. Here, we report the draft genome sequence of a multidrug-resistant A. baumannii(ST15/CC15) isolated in 2009 from the state of Espírito Santo (Southeast Brazil). We observed important resistance determinant genes in an estimated genome size of 4,102,788 bp with 3,862 predicted coding regions. A detailed report of the genomic data analysis might help to understand the specific features of highly successful strains belonged to a relevant complex clonal in different Brazilian geographical regions.

ExoU is an important virulence factor in acute Pseudomonas aeruginosa infections. Here, we unveiled the mechanisms of ExoU-driven NF-κB activation by using human airway cells and mice infected with P. aeruginosa strains. Several approaches showed that PAFR was crucially implicated in the activation of the canonical NF-κB pathway. Confocal microscopy of lungs from infected mice revealed that PAFR-dependent NF-κB activation occurred mainly in respiratory epithelial cells, and reduced p65 nuclear translocation was detected in mice PAFR-/- or treated with the PAFR antagonist WEB 2086. Several evidences showed that ExoU-induced NF-κB activation regulated PAFR expression. First, ExoU increased p65 occupation of PAFR promoter, as assessed by ChIP. Second, luciferase assays in cultures transfected with different plasmid constructs revealed that ExoU promoted p65 binding to the three κB sites in PAFR promoter. Third, treatment of cell cultures with the NF-κB inhibitor Bay 11-7082, or transfection with IκBα negative-dominant, significantly decreased PAFR mRNA. Finally, reduction in PAFR expression was observed in mice treated with Bay 11-7082 or WEB 2086 prior to infection. Together, our data demonstrate that ExoU activates NF-κB by PAFR signalling, which in turns enhances PAFR expression, highlighting an important mechanism of amplification of response to this P. aeruginosa toxin., (© 2014 John Wiley & Sons Ltd.)

Objective: To analyze and compare the mutations in two different regions of the katG gene, which is responsible for isoniazid (INH) resistance., Methods: We analyzed 97 multidrug-resistant Mycobacterium tuberculosis strains isolated in cultures of sputum samples obtained from the Professor Hélio Fraga Referral Center, in Brasília, Brazil. Another 6 INH-sensitive strains did not present mutations and were included as controls. We used PCR to amplify two regions of the katG gene (GenBank accession no. U06258)-region 1, (from codon 1 to codon 119) and region 2 (from codon 267 to codon 504)-which were then sequenced in order to identify mutations., Results: Seven strains were resistant to INH and did not contain mutations in either region. Thirty strains carried mutations in region 1, which was characterized by a high number of deletions, especially at codon 4 (24 strains). Region 2 carried 83 point mutations, especially at codon 315, and there was a serine-to-threonine (AGC-to-ACC) substitution in 73 of those cases. The analysis of region 2 allowed INH resistance to be diagnosed in 81.4% of the strains. Nine strains had mutations exclusively in region 1, which allowed the proportion of INH-resistant strains identified to be increased to 90.6%., Conclusions: The number of mutations at codon 315 was high, which is consistent with cases described in Brazil and in other countries, and the analysis of region 1 resulted in a 9.2% increase in the rate at which mutations were identified.