Dataset Information

Biofilm formation in enterococci: genotype-phenotype correlations and inhibition by vancomycin.

ABSTRACT: Enterococci are nosocomial pathogens that can form biofilms, which contribute to their virulence and antibiotic resistance. Although many genes involved in biofilm formation have been defined, their distribution among enterococci has not been comprehensively studied on a genome scale, and their diagnostic ability to predict biofilm phenotypes is not fully established. Here, we assessed the biofilm-forming ability of 90 enterococcal clinical isolates. Major patterns of virulence gene distribution in enterococcal genomes were identified, and the differentiating virulence genes were screened by polymerase chain reaction (PCR) in 31 of the clinical isolates. We found that detection of gelE in Enterococcus faecalis is not sufficient to predict gelatinase activity unless fsrAB, or fsrB alone, is PCR-positive (P?=?0.0026 and 0.0012, respectively). We also found that agg is significantly enriched in isolates with medium and strong biofilm formation ability (P?=?0.0026). Additionally, vancomycin, applied at sub minimal inhibitory concentrations, inhibited biofilm in four out of five strong biofilm-forming isolates. In conclusion, we suggest using agg and fsrB genes, together with the previously established gelE, for better prediction of biofilm strength and gelatinase activity, respectively. Future studies should explore the mechanism of biofilm inhibition by vancomycin and its possible use for antivirulence therapy.

SUBMITTER: Hashem YA

PROVIDER: S-EPMC5515943 | biostudies-literature | 2017 Jul

REPOSITORIES: biostudies-literature

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Biofilm formation in enterococci: genotype-phenotype correlations and inhibition by vancomycin.

Hashem Yomna A YA Amin Heba M HM Essam Tamer M TM Yassin Aymen S AS Aziz Ramy K RK

Scientific reports 20170718 1

Enterococci are nosocomial pathogens that can form biofilms, which contribute to their virulence and antibiotic resistance. Although many genes involved in biofilm formation have been defined, their distribution among enterococci has not been comprehensively studied on a genome scale, and their diagnostic ability to predict biofilm phenotypes is not fully established. Here, we assessed the biofilm-forming ability of 90 enterococcal clinical isolates. Major patterns of virulence gene distribution ...[more]

PMID: 28720810

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Project description:Enterococci and biofilm-associated infections are a growing problem worldwide, given the rise in antibiotic resistance in environmental and clinical settings. The increasing incidence of antibiotic resistance and its propagation potential within enterococcal biofilm is a concern. This requires a deeper understanding of how enterococcal biofilm develops, and how antibiotic resistance transfer takes place in these biofilms. Enterococcal biofilm assays, incorporating the study of antibiotic resistance transfer, require a system which can accommodate non-destructive, real-time experimentation. We adapted a Gene Frame® combined with fluorescence microscopy as a novel non-destructive platform to study the conjugal transfer of vancomycin resistance in an established enterococcal biofilm.A multi-purpose fluorescent in situ hybridisation (FISH) probe, in a novel application, allowed the identification of low copy number mobile elements in the biofilm. Furthermore, a Hoechst stain and ENU 1470 FISH probe identified Enterococcus faecium transconjugants by excluding Enterococcus faecalis MF06036 donors. Biofilm created with a rifampicin resistant E. faecalis (MW01105Rif) recipient had a transfer efficiency of 2.01 × 10-3; double that of the biofilm primarily created by the donor (E. faecalis MF06036). Conjugation in the mixed enterococcal biofilm was triple the efficiency of donor biofilm. Double antibiotic treatment plus lysozyme combined with live/dead imaging provided fluorescent micrographs identifying de novo enterococcal vancomycin resistant transconjugants inside the biofilm. This is a model system for the further study of antibiotic resistance transfer events in enterococci. Biofilms promote the survival of enterococci and reduce the effectiveness of drug treatment in clinical settings, hence giving enterococci an advantage. Enterococci growing in biofilms exchange traits by means of horizontal gene transfer, but currently available models make study difficult. This work goes some way to providing a non-destructive, molecular imaging-based model system for the detection of antibiotic resistance gene transfer in enterococci.

Project description:RYR1 mutations are typically associated with core myopathies and are the most common overall cause of congenital myopathy. Dominant mutations are most often associated with central core disease and malignant hyperthermia, and genotype-phenotype patterns have emerged from the study of these mutations that have contributed to the understanding of disease pathogenesis. The recent availability of genetic testing for the entire RYR1 coding sequence has led to a dramatic expansion in the identification of recessive mutations in core myopathies and other congenital myopathies. To date, no clear patterns have been identified in these recessive mutations, though no systematic examination has yet been performed.In this study, we investigated genotype-phenotype correlations in a large combined cohort of unpublished (n?=?14) and previously reported (n?=?92) recessive RYR1 cases.Overall examination of this cohort revealed nearly 50% of cases to be non-core myopathy related. Our most significant finding was that hypomorphic mutations (mutations expected to diminish RyR1 expression) were enriched in patients with severe clinical phenotypes. We also determined that hypomorphic mutations were more likely to be encountered in non-central core myopathies. With analysis of the location of non-hypomorphic mutations, we found that missense mutations were generally enriched in the MH/CCD hotspots and specifically enriched in the selectivity filter of the channel pore.These results support a hypothesis that loss of protein function is a key predictive disease parameter. In addition, they suggest that decreased RyR1 expression may dictate non-core related pathology though, data on protein expression was limited and should be confirmed in a larger cohort. Lastly, the results implicate abnormal ion conductance through the channel pore in the pathogenesis in recessive core myopathies. Overall, our findings represent a comprehensive analysis of genotype-phenotype associations in recessive RYR1-myopathies.

Dataset Information

Biofilm formation in enterococci: genotype-phenotype correlations and inhibition by vancomycin.

Publications

Biofilm formation in enterococci: genotype-phenotype correlations and inhibition by vancomycin.

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