Alojamiento para los refugiados que llegan a Grecia, 2015-2017

Las llegadas masivas a Grecia desde 2015 han superado con creces la provisión de alojamiento aceptable. Los intentos para ofrecer soluciones continúan

IncHI plasmids, a dynamic link between resistance and pathogenicity

Plasmids of incompatibility group (Inc) HI1 are important vectors of antibiotic resistance in both of the major causal agents of enteric fever: Salmonella enterica subspecies enterica serovar Typhi and S. Paratyphi A. In S. Typhi, IncHI1 plasmids appeared in the 1970s and spread globally. In some circumstances they are maintained within the bacterial population even in the absence of selection from antibiotics. The low cost associated with IncH plasmids in Salmonella is due, in part, to the presence of a plasmid gene encoding an H-NS-like global regulator which acts co-operatively with chromosomally encoded H-NS. Very recently, IncHI1 plasmids have crossed from S. Typhi into S. Paratyphi A; the acquisition of drug resistance and possibly other phenotypic traits encoded by IncHI1 plasmids has increased the virulence potential of this neglected pathogen. There is no vaccine for S. Paratyphi A and resistance to the current drugs of choice, the fluoroquinolones, is also spreading rapidly. There is a conserved backbone to all IncH plasmids but variation occurs in regions of the plasmids associated with antibiotic resistance. These IncHI1 plasmids are allowing major human pathogens to sample genes available in their environment, the human gut, and will be maintained by enhancing the competitive advantage of the bacterial host. Therefore competition between closely related resistance plasmids will probably increase the transmission of enteric fever by enhancing the fitness of their bacterial hosts

Genetic markers in s. Paratyphi c reveal primary adaptation to pigs

Salmonella enterica with the identical antigenic formula 6,7:c:1,5 can be differentiated biochemically and by disease syndrome. One grouping, Salmonella Paratyphi C, is currently considered a typhoidal serovar, responsible for enteric fever in humans. The human-restricted typhoidal serovars (S. Typhi and Paratyphi A, B and C) typically display high levels of genome degradation and are cited as an example of convergent evolution for host adaptation in humans. However, S. Paratyphi C presents a different clinical picture to S. Typhi/Paratyphi A, in a patient group with predisposition, raising the possibility that its natural history is different, and that infection is invasive salmonellosis rather than enteric fever. Using whole genome sequencing and metabolic pathway analysis, we compared the genomes of 17 S. Paratyphi C strains to other members of the 6,7:c:1,5 group and to two typhoidal serovars: S. Typhi and Paratyphi A. The genome degradation observed in S. Paratyphi C was much lower than S. Typhi/Paratyphi A, but similar to the other 6,7:c:1,5 strains. Genomic and metabolic comparisons revealed little to no overlap between S. Paratyphi C and the other typhoidal serovars, arguing against convergent evolution and instead providing evidence of a primary adaptation to pigs in accordance with the 6,7:c:1.5 strains

Using next generation sequencing to tackle non-typhoidal Salmonella infections.

The publication of studies using next generation sequencing to analyse large numbers of bacterial isolates from global epidemics is transforming microbiology, epidemiology and public health. The emergence of multidrug resistant Salmonella Typhimurium ST313 is one example. While the epidemiology in Africa appears to be human-to-human spread and the association with invasive disease almost absolute, more needs to be done to exclude the possibility of animal reservoirs and to transfer the ability to track all Salmonella infections to the laboratories in the front line. In this mini-review we summarise what is currently known about non-typhoidal Salmonella in sub-Saharan Africa and discuss some of the issues which remain

Identification and characterisation of enteroaggregative Escherichia coli subtypes associated with human disease

Enteroaggregative E. coli (EAEC) are a major cause of diarrhoea worldwide. Due to their heterogeneity and carriage in healthy individuals, identification of diagnostic virulence markers for pathogenic strains has been difficult. In this study, we have determined phenotypic and genotypic differences between EAEC strains of sequence types (STs) epidemiologically associated with asymptomatic carriage (ST31) and diarrhoeal disease (ST40). ST40 strains demonstrated significantly enhanced intestinal adherence, biofilm formation, and pro-inflammatory interleukin-8 secretion compared with ST31 isolates. This was independent of whether strains were derived from diarrhoea patients or healthy controls. Whole genome sequencing revealed differences in putative virulence genes encoding aggregative adherence fimbriae, E. coli common pilus, flagellin and EAEC heat-stable enterotoxin 1. Our results indicate that ST40 strains have a higher intrinsic potential of human pathogenesis due to a specific combination of virulence-related factors which promote host cell colonization and inflammation. These findings may contribute to the development of genotypic and/or phenotypic markers for EAEC strains of high virulence

A novel broadly applicable PCR-RFLP method for rapid identification and subtyping of H58 Salmonella Typhi

Salmonella Typhi (S. Typhi), the human-adapted agent of typhoid fever, is genetically monomorphic. SNPs accumulation divided the S. Typhi population in 85 haplotypes (H) of which one, H58, has undergone a clonal expansion. The surveillance of H58 S. Typhi is particularly important, especially in areas where typhoid fever is endemic. We developed a simple PCR and PCR-RFLP method to detect and subtype H58 S. Typhi based on the presence of genomic deletion and specific SNPs. The method was validated against 39 S. Typhi isolates of known haplotype, showing 100% of specificity and high sensitivity, and then used to screen a collection of 99 S. Typhi from Asia, demonstrating a high incidence of H58 S. Typhi in Jordan and India. Our method is designed to be applied in all laboratories with basic molecular biology equipment and few financial resources and allows the surveillance of H58 S. Typhi in resource poor settings

Whole-genome sequencing for national surveillance of Shiga toxin–producing Escherichia coli O157

Background. National surveillance of gastrointestinal pathogens, such as Shiga toxin–producing Escherichia coli O157 (STEC O157), is key to rapidly identifying linked cases in the distributed food network to facilitate public health interventions. In this study, we used whole-genome sequencing (WGS) as a tool to inform national surveillance of STEC O157 in terms of identifying linked cases and clusters and guiding epidemiological investigation. Methods. We retrospectively analyzed 334 isolates randomly sampled from 1002 strains of STEC O157 received by the Gastrointestinal Bacteria Reference Unit at Public Health England, Colindale, in 2012. The genetic distance between each isolate, as estimated by WGS, was calculated and phylogenetic methods were used to place strains in an evolutionary context. Results. Estimates of linked clusters representing STEC O157 outbreaks in England and Wales increased by 2-fold when WGS was used instead of traditional typing techniques. The previously unidentified clusters were often widely geographically distributed and small in size. Phylogenetic analysis facilitated identification of temporally distinct cases sharing common exposures and delineating those that shared epidemiological and temporal links. Comparison with multi locus variable number tandem repeat analysis (MLVA) showed that although MLVA is as sensitive as WGS, WGS provides a more timely resolution to outbreak clustering. Conclusions. WGS has come of age as a molecular typing tool to inform national surveillance of STEC O157; it can be used in real time to provide the highest strain-level resolution for outbreak investigation. WGS allows linked cases to be identified with unprecedented specificity and sensitivity that will facilitate targeted and appropriate public health investigations

Safety and efficacy of 2% chlorhexidine gluconate aqueous versus 2% chlorhexidine gluconate in 70% isopropyl alcohol for skin disinfection prior to percutaneous central venous catheter insertion in preterm neonates:The ARCTIC randomised-controlled feasibility trial protocol

Introduction Catheter-related sepsis is one of the most dangerous complications of neonatal intensive care and is associated with significant morbidity and mortality. Use of catheter-care € bundles' has reduced the incidence of catheter-related sepsis, although individual components have not been well studied. Better evidence is needed to guide selection of the most appropriate antiseptic solution for skin disinfection in preterm neonates. This study will inform the feasibility and design of the first randomised controlled trial to examine the safety and efficacy of alcohol-based versus aqueous-based chlorhexidine antiseptic formulations for skin disinfection prior to percutaneous central venous catheterisation in preterm neonates. The antiseptics to be compared are 2% chlorhexidine gluconate (CHG) aqueous and 2% CHG in 70% isopropyl alcohol. Methods and analysis The Antiseptic Randomised Controlled Trial for Insertion of Catheters (ARCTIC) is a two-centre randomised-controlled feasibility trial. At least 100 preterm infants born at <34 weeks' gestation and due to undergo percutaneous insertion of a central venous catheter will be randomly allocated to receive prior skin disinfection with one of the two antiseptic solutions. Outcomes include: i) recruitment and retention rates; ii) completeness of data collection; iii) numbers of enrolled infants meeting case definitions for definite catheter-related sepsis, catheter-associated sepsis and catheter colonisation and iv) safety outcomes of skin morbidity scores recorded daily from catheter insertion until 48 hours post removal. The key feasibility metrics will be reported as proportions with 95% CIs. Estimated prevalence of catheter colonisation will allow calculation of sample size for the large-scale trial. The data will inform whether it will be feasible to progress to a large-scale trial. Ethics and dissemination ARCTIC has been approved by the National Health Service Health Research Authority National Research Ethics Service Committee East of England (Cambridge South) (IRAS ID 163868), was adopted onto the National Institute of Health Research Clinical Research Network portfolio (CPMS ID 19899) and is registered with an International Standard Randomised Control Trials Number (ISRCTN: 82571474; Pre-results) and European Clinical Trials Database number 2015-000874-36. Dissemination plans include presentations at scientific conferences, scientific publications and sharing of the findings with parents via the support of Bliss baby charity

Development and evaluation of a multiple-locus variable-number tandem-repeats analysis assay for subtyping Salmonella Typhi strains from sub-Saharan Africa

Purpose: Molecular epidemiological investigations of the highly clonal Salmonella enterica subspecies enterica serovar Typhi (S. Typhi) are important in outbreak detection and in tracking disease transmission. In this study, we developed and evaluated a multiple-locus variable-number tandem-repeats (VNTR) analysis (MLVA) assay for characterization of S. Typhi isolates from sub-Saharan Africa. Methodology: Twelve previously reported VNTR loci were evaluated and an MLVA assay consisting of five polymorphic loci was adopted. The MLVA assay was developed for use on capillary electrophoresis systems by testing a collection of 50 S. Typhi isolates. This S. Typhi strain panel consisted of six outbreak related isolates and 44 epidemiologically unlinked isolates. Amongst these were nine S.Typhi haplotype H58 isolates. Results: The MLVA assay characterized the 50 isolates into 47 MLVA profiles while PFGE analysis of the same isolates revealed 34 pulsotypes. MLVA displayed higher discriminatory power (Simpson’s index of diversity (DI) 0.998 [95% confidence interval (CI) 0.995–1.000)] as compared to pulsed-field gel electrophoresis [Simpson’s DI 0.984 (95% CI 0.974–0.994)]. Conclusion: The MLVA assay presented in this study is a simple, rapid and more accessible tool that serves as a good alternative to other molecular subtyping methods for S. Typhi

Detection of mutations in gyrB using denaturing high performance liquid chromatography (DHPLC) among Salmonella enterica serovar Typhi and Paratyphi A

Background:- Fluoroquinolone resistance is mediated by mutations in the quinolone-resistance determining region (QRDR) of the topoisomerase genes. Denaturing high performance liquid chromatography (DHPLC) was evaluated for detection of clinically important mutations in gyrB among Salmonella. Method:- S. Typhi and S. ParatyphiA characterised for mutation in QRDR of gyrA, parC and parE were studied for mutation in gyrB by DHPLC and validated by sequencing. Result:- The DHPLC analysis was able to resolve the test mutant from isolates with wild type gyrB and distinguished mutants from other mutant by peak profile and shift in retention time. Three sequence variants were detected at codon 464, and a novel mutation Ser→Thr was also detected. gyrB mutation was associated with non classical quinolone resistance (NALS-CIPDS) in 34 isolates of S. Typhi only and was distinct from classical quinolone resistance associated with gyrA mutations (NALR-CIPDS). Conclusion: DHPLC is effective for the detection of mutation and can reduce the need forsequencing to detect clinically significant gyrB mutations.