Vancomycin-Resistant Enterococcus: Infectious Endocarditis Treatment

Application of multilocus sequence analysis (MLSA) for rapid identification of Enterococcus species based on rpoA and pheS genes

The aim of this study was to evaluate the use of RNA polymeraseαsubunit (rpoA) and phenylalanyl-tRNA synthase (pheS) gene sequences as species identification tools for enterococci. Ninety-six representative strains comprising all currently recognizedEnterococcusspecies were examined.rpoAgene sequences generated a robust classification into species groups similar to the one based on 16S rRNA gene sequence analysis. On the other hand, thepheSgene is a fast-evolving clock even better suited for species delineation than therpoAgene, but not for recognition of species groups withinEnterococcusas determined by bothrpoAand 16S rRNA genes. All enterococcal species were clearly differentiated on the basis of theirrpoAandpheSsequences. Evaluation of intraspecies variation showed that bothrpoAandpheSgenes have a high degree of homogeneity among strains of the same species. Strains of the same enterococcal species have at least 99 %rpoAand 97 %pheSgene sequence similarity, whereas, different enterococcal species have at maximum 97 %rpoAand 86 %pheSgene sequence similarity. It was concluded that both genes can be used as reliable tools for identification of clinical and environmental species ofEnterococcusand are efficient screening methods for the detection of novel species. The sequence data obtained in this study were compared to the availableatpAand 16S rRNA gene sequences. The MLSA approach toEnterococcustaxonomy provides portable, highly reproducible data with lower costs for rapid identification of all enterococcal species.

Enterococci from foods

Enterococci have recently emerged as nosocomial pathogens. Their ubiquitous nature determines their frequent finding in foods as contaminants. In addition, the notable resistance of enterococci to adverse environmental conditions explains their ability to colonise different ecological niches and their spreading within the food chain through contaminated animals and foods. Enterococci can also contaminate finished products, such as fermented foods and, for this reason, their presence in many foods (such as cheeses and fermented sausages) can only be limited but not completely eliminated using traditional processing technologies. Enterococci are low grade pathogens but their intrinsic resistance to many antibiotics and their acquisition of resistance to the few antibiotics available for treatment in clinical therapy, such as the glycopeptides, have led to difficulties and a search for new drugs and therapeutic options. Enterococci can cause food intoxication through production of biogenic amines and can be a reservoir for worrisome opportunistic infections and for virulence traits. Clearly, there is no consensus on the acceptance of their presence in foodstuffs and their role as primary pathogens is still a question mark. In this review, the following topics will be covered: (i) emergence of the enterococci as human pathogens due to the presence of virulence factors such as the production of adhesins and aggregation substances, or the production of biogenic amines in fermented foods; (ii) their presence in foods; (iii) their involvement in food-borne illnesses; (iv) the presence, selection and spreading of antibiotic-resistant enterococci as opportunistic pathogens in foods, with particular emphasis on vancomycin-resistant enterococci.

Prosthetic valve endocarditis due to vancomycin-resistant Enterococcus faecium: treatment with chloramphenicol plus minocycline

We report a case of prosthetic valve endocarditis and persistent bacteremia due to vancomycin-resistant Enterococcus faecium. The combination of parenteral chloramphenicol plus minocycline therapy was administered for 8 weeks and resulted in cure after treatment with quinupristin-dalfopristin had failed.

Two-stage exchange hip arthroplasty for deep infection

Although the risk of infection after total hip arthroplasty has decreased over the last three decades with the use of prophylactic antibiotics, laminar airflow operating rooms and whole-body exhaust suites, deep infection after total hip arthroplasty remains a serious complication. Significant morbidity to the patient and the cost to the health care system remain. During this period of time, diagnostic techniques also have improved including the use of polymerase chain reaction amplification. Treatment options now include: suppressive antibiotics, irrigation and debridement with retention of components, one-stage reimplantation, two-stage reimplantation, and salvage procedures. Based on the medical literature, the successful eradication of a total joint replacement infection with a two-stage reimplantation protocol is over 90% while the success rate with a one-stage protocol is approximately 80%. These success rates may decline however as the prevalence of antibiotic resistant organisms increases. Current controversies regarding two-stage reimplantation protocols include: duration of intravenous antibiotic therapy, timing of the reimplantation, the use of allograft bone in the reconstruction, the choice of fixation (cement versus cementless), and the use of antibiotic-loaded cement spacers.