Molecular analysis of clonally related Salmonella Typhi recovered from epidemiologically unrelated cases of typhoid fever, Brazil

BACKGROUND

The primary method of molecular subtyping for the identification and investigation of outbreaks has been pulsed-field gel electrophoresis (PFGE). In some cases, this technique has not been able to show discrimination between the unrelated strains that can be achieved by whole genome sequencing (WGS).

METHODS

The aim of this study was to determine the strengths and drawbacks of WGS using different analytic approaches compared to traditional typing method, PFGE, for retrospectively typing clusters cases of 28 S. Typhi.

RESULTS

We evaluated three analytical approaches on the WGS data set (Nucleotide Difference (ND), (SNPs) and Whole genome multi locus sequence typing (wgMLST) that identically classified the clusters-related strains into two clusters, cluster A (with strains from 2017), and Cluster B (with strains from 2007).

CONCLUSIONS

In this study WGS based typing, was able to compete with PFGE for differentiation of the clusters of S. Typhi strains.

Subtyping of plasmid-mediated quinolone resistance among Salmonella serotypes by whole genome sequencing

Most known plasmids are identified by conferring virulence or antimicrobial resistance phenotypes and such characteristics aid in the success of the dispersion of different plasmid types between bacteria from different sources. This study aimed to perform the subtyping of the plasmid-mediated quinolone resistance, detected in Salmonella spp. A total of 34 Salmonella strains non-susceptible to ciprofloxacin were evaluated. Strains were selected based on the presence of PMQR determined by Polymerase Chain Reaction and further submitted to Next Generation Sequencing. Most of the strains presented the qnrB19 in small ColE-like plasmids and qnrB2 gene associated with IncN/ST5 plasmids also detected. Our results indicated the co-occurrence of PMQR and ESBLs in plasmids that are a lineage of epidemic plasmids circulating in Salmonella in which additional resistances were detected, highlighting the potential threat of resistance Salmonella to public health, particularly in infections in which antimicrobial therapy is needed.

Emergence of CMY-2-Producing Salmonella Heidelberg Associated with IncI1 Plasmids Isolated from Poultry in Brazil

In this study we report the characterization of plasmid-mediated CMY-2-producing Salmonella Heidelberg recovered from food, poultry, and poultry environment in Brazil, between 2014 and 2016. The bla_CMY-2 resistance gene was allocated in large (90-148 kb) IncI1 type transferable plasmids. Salmonella Heidelberg isolates were genetically related, indicating the dissemination of closely related isolates among food, poultry, and its environment. This is the first report of IncI1 replicon-types of plasmids encoding the bla_CMY-2 resistance gene in Salmonella Heidelberg isolates in Brazil, the world's biggest exporter of chickens.

Nutritional vitamin A status in northeast Brazilian lactating mothers

BACKGROUND

Vitamin A deficiency is the major cause of morbidity and mortality among children and in women of reproductive age in developing countries. The present study aimed to assess maternal nutritional vitamin A status, as well as analyse the association of preformed vitamin A and pro-vitamin A consumption on the nutritional status of nursing mothers, based on serum retinol and retinol colostrum concentrations coupled with dietary intake.

METHODS

Serum and colostrums were collected from 86 healthy parturients, recruited within 16 h postpartum. Blood samples were obtained, the morning after an overnight fast. Retinol was analysed by high-performance liquid chromatography. Dietary vitamin A was assessed using a food frequency questionnaire and the women were separated into two groups according to the predominant dietary source of vitamin A: group A, > 50% preformed vitamin A (n = 37); and group B > 50% pro-vitamin A carotenoids, (n = 49).

RESULTS

Serum retinol and total vitamin A ingestion (mean +/- SD) were higher in group A than in group B (1.4 +/- 0.4 micromol L(-1) and 2072.0 +/- 1465.9 microg retinol activity equivalent (RAE) day(-1) versus 1.2 +/- 0.6 micromol L(-1) and 1051.6 +/- 920.4 microg RAE day(-1), respectively (P < 0.05), but colostrum retinol (3.4 +/- 1.7 micromol L(-1) and 3.6 +/- 1.9 micromol L(-1)) was similar in both groups. In group B, 36.7% (n = 18) of the nursing mothers presented a risk of developing vitamin A deficiency, based on their dietary intake.

CONCLUSIONS

On the basis of the intake of the pro-vitamin A carotenoids, some women may be at risk of vitamin A deficiency. However, their status is currently normal, as indicated by serum and milk retinol concentrations.