Recent data indicates an increasing rate of vancomycin resistance in clinical enterococcal isolates worldwide. The nosocomial enterococci are likely to harbor virulence elements that increase their ability to colonize hospitalized patients. The aim of this study was to characterize virulence determinants in vancomycin-resistant enterococci (VRE) obtained from various clinical sources.During the years 2008 to 2010, a total of 48 VRE isolates were obtained from three University teaching hospitals in Northwest, Iran. Initially, phenotypic speciation was done and minimum inhibitory concentrations (MICs) of vancomycin were determined by agar dilution method and E-test. Then, species identification and resistance genotypes along with detection of virulence genes (asa1, esp, gelE, ace and cpd) of the isolates were performed by multiplex PCR.Thirty eight isolates were identified as vancomycin-resistant Enterococcus faecium (VREfm) and ten as E. faecalis (VREfs). Irrespective of the species, vanA gene (89.58%) was dominant and three phenotypically vancomycin susceptible E. faecium isolates carried the vanB gene. Among virulence genes investigated, the esp was found in 27(71%) VREfm strains, but did not in any VREfs. Other virulence determinants were highly detected in VREfs strains. Our data indicate a high prevalence of E. faecium harboring vancomycin resistance with vanA genotype and the two VRE species displayed different virulence genes.
The aim of this study was to characterize virulence determinants and antibiotic resistance profiles in enterococci obtained from various clinical sources in the northwest of Iran. A total of 160 enterococcal clinical isolates from various wards of University Teaching Hospitals were collected and specified by biochemical test, from September 2014 to July 2015. Identification of enterococci was confirmed by multiplex PCR in the genus and species level. Antibiotic resistance properties and virulence determinants were examined by phenotypic and molecular methods. Of 160 enterococcal isolates, 125 (78.12%) and 35 (21.88%) isolates were identified as Enterococcus faecalis and Enterococcus faecium, respectively. The most common antibiotic nonsusceptible pattern observed was resistance toward rifampicin [n = 122 (76.25%)] followed by erythromycin [n = 117 (73.12%)]. Among all isolates, gelE [n = 140 (87.5%)], cpd [n = 137 (85.6%)], and asa1 [n = 118 (73.8%)] were the most prevalent virulence genes studied. Thirty isolates (11 E. faecalis, 19 E. faecium) were found to be resistant to vancomycin, with minimum inhibitory concentration of ≥256 μg/ml. Twenty-seven isolates carried the vanA gene, whereas none of the isolates carried vanB. E. faecalis had a considerable ability to show virulence genes and drug resistance. Emergence of antibiotic-resistant enterococci and the high prevalence of virulence traits in our study could be regarded as an alarming situation.
Alteration in the composition of the gut microbiota can lead to a number of chronic clinical diseases.
Akkermansia muciniphila
is an anaerobic bacteria constituting 3–5% of the gut microbial community in healthy adults. This bacterium is responsible for degenerating mucin in the gut; its scarcity leads to diverse clinical disorders. In this review, we focus on the role of
A. muciniphila
in diabetes, obesity and atherosclerosis, as well as the use of this bacterium as a next-generation probiotic. In regard to obesity and diabetes, human and animal trials have shown that
A. muciniphila
controls the essential regulatory system of glucose and energy metabolism. However, the underlying mechanisms by which
A. muciniphila
alleviates the complications of obesity, diabetes and atherosclerosis are unclear. At the same time, its abundance suggests improved metabolic disorders, such as metabolic endotoxemia, adiposity insulin resistance and glucose tolerance. The role of
A. muciniphila
is implicated in declining aortic lesions and atherosclerosis. Well-characterized virulence factors, antigens and cell wall extracts of
A. muciniphila
may act as effector molecules in these diseases. These molecules may provide novel mechanisms and strategies by which this bacterium could be used as a probiotic for the treatment of obesity, diabetes and atherosclerosis.
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