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1.  Potent bactericidal efficacy of copper oxide impregnated non-porous solid surfaces 
BMC Microbiology  2014;14:57.
The role of fomites and the environment in nosocomial infections is becoming widely recognized. In this paper we discuss the use of Cupron copper oxide impregnated non-porous solid surface in the hospital setting and present in vitro testing data via USA Environmental Protection Agency (EPA) approved testing protocols that demonstrate the efficacy of these products to assist in reduction in environmental contamination and potentially nosocomial infections.
The two countertops tested passed all the acceptance criteria by the EPA (>99.9% kill within 2 hours of exposure) killing a range of bacterial pathogens on the surface of the countertops even after repeated exposure of the countertops to the pathogen, and multiple wet and dry abrasion cycles.
Cupron enhanced EOS countertops thus may be an important adjunct to be used in hospital settings to reduce environmental bioburden and potentially nosocomial infections.
PMCID: PMC3973859  PMID: 24606672
Copper oxide; EPA registered; Antimicrobial surface; Environmental bioburden
2.  Analysis of the Genotype and Virulence of Staphylococcus epidermidis Isolates from Patients with Infective Endocarditis▿ †  
Infection and Immunity  2008;76(11):5127-5132.
Staphylococcus epidermidis is one of the most common causes of infections of prosthetic heart valves (prosthetic valve endocarditis [PVE]) and an increasingly common cause of infections of native heart valves (native valve endocarditis [NVE]). While S. epidermidis typically causes indolent infections of prosthetic devices, including prosthetic valves and intravascular catheters, S. epidermidis NVE is a virulent infection associated with valve destruction and high mortality. In order to see if the differences in the course of infection were due to characteristics of the infecting organisms, we examined 31 S. epidermidis NVE and 65 PVE isolates, as well as 21 isolates from blood cultures (representing bloodstream infections [BSI]) and 28 isolates from nasal specimens or cultures considered to indicate skin carriage. Multilocus sequence typing showed both NVE and PVE isolates to have more unique sequence types (types not shared by the other groups; 74 and 71%, respectively) than either BSI isolates (10%) or skin isolates (42%). Thirty NVE, 16 PVE, and a total of 9 of the nasal, skin, and BSI isolates were tested for virulence in Caenorhabditis elegans. Twenty-one (70%) of the 30 NVE isolates killed at least 50% of the worms by day 5, compared to 1 (6%) of 16 PVE isolates and 1 (11%) of 9 nasal, skin, or BSI isolates. In addition, the C. elegans survival rate as assessed by log rank analyses of Kaplan-Meier survival curves was significantly lower for NVE isolates than for each other group of isolates (P < 0.0001). There was no correlation between the production of poly-β(1-6)-N-acetylglucosamine exopolysaccharide and virulence in worms. This study is the first analysis suggesting that S. epidermidis isolates from patients with NVE constitute a more virulent subset within this species.
PMCID: PMC2573358  PMID: 18794284
3.  Gene Acquisition at the Insertion Site for SCCmec, the Genomic Island Conferring Methicillin Resistance in Staphylococcus aureus▿  
Journal of Bacteriology  2007;190(4):1276-1283.
Staphylococcus aureus becomes resistant to methicillin by acquiring a genomic island, known as staphylococcal chromosome cassette mec (SCCmec), which contains the methicillin resistance determinant, mecA. SCCmec is site-specifically integrated into the staphylococcal chromosome at a locus known as the SCCmec attachment site (attB). In an effort to gain a better understanding of the potential that methicillin-sensitive S. aureus (MSSA) isolates have for acquiring SCCmec, the nucleotide sequences of attB and surrounding DNA regions were examined in a diverse collection of 42 MSSA isolates. The chromosomal region surrounding attB varied among the isolates studied and appears to be a common insertion point for acquired foreign DNA. Insertions of up to 15.1 kb were found containing open reading frames with homology to enterotoxin genes, restriction-modification systems, transposases, and several sequences that have not been previously described in staphylococci. Two groups, containing eight and four isolates, had sequences found in known SCCmec elements, suggesting SCCmec elements may have evolved through repeated DNA insertions at this locus. In addition, the attB sequences of the majority of MSSA isolates in this collection differ from the attB sequences of strains for which integrase-mediated SCCmec insertion or excision has been demonstrated, suggesting that some S. aureus isolates may lack the ability to site-specifically integrate SCCmec into their chromosomes.
PMCID: PMC2238224  PMID: 18083809
4.  Evaluation of Molecular Typing Methods in Characterizing a European Collection of Epidemic Methicillin-Resistant Staphylococcus aureus Strains: the HARMONY Collection▿  
Journal of Clinical Microbiology  2007;45(6):1830-1837.
We analyzed a representative sample of methicillin-resistant Staphylococcus aureus (MRSA) from 11 European countries (referred to as the HARMONY collection) using three molecular typing methods used within the HARMONY group to examine their usefulness for large, multicenter MRSA surveillance networks that use these different laboratory methodologies. MRSA isolates were collected based on their prevalence in each center and their genetic diversity, assessed by pulsed-field gel electrophoresis (PFGE). PFGE groupings (≤3 bands difference between patterns) were compared to those made by sequencing of the variable repeats in the protein A gene spa and clonal designations based on multilocus sequence typing (MLST), combined with PCR analysis of the staphylococcal chromosome cassette containing the mec genes involved in methicillin resistance (SCCmec). A high level of discrimination was achieved using each of the three methodologies, with discriminatory indices between 89.5% and 91.9% with overlapping 95% confidence intervals. There was also a high level of concordance of groupings made using each method. MLST/SCCmec typing distinguished 10 groups containing at least two isolates, and these correspond to the majority of nosocomial MRSA clones described in the literature. PFGE and spa typing resolved 34 and 31 subtypes, respectively, within these 10 MRSA clones, with each subtype differing only slightly from the most common pattern using each method. The HARMONY group has found that the methods used in this study differ in their availability and affordability to European centers involved in MRSA surveillance. Here, we demonstrate that the integration of such technologies is achievable, although common protocols (such as we have developed for PFGE) may also be important, as is the use of centralized Internet sites to facilitate data analysis. PFGE and spa-typing data from analysis of MRSA isolates from the many centers that have access to the relevant equipment can be compared to reference patterns/sequences, and clonal designations can be made. In the majority of cases, these will correspond to those made by the (more expensive) method of choice—MLST/SCCmec typing—and these alternative methods can therefore be used as frontline typing systems for multicenter surveillance of MRSA.
PMCID: PMC1933060  PMID: 17428929
5.  Use of Outer Surface Protein Repeat Regions for Improved Genotyping of Staphylococcus epidermidis▿  
Journal of Clinical Microbiology  2007;45(3):730-735.
Staphylococcus epidermidis is an important nosocomial pathogen, but little is known of its epidemiology. Accurate, reproducible typing systems would greatly improve epidemiologic investigations of S. epidermidis. The sequence-based typing technique most recently evaluated, multilocus sequence typing (MLST), often lacks discrimination and can be expensive. PCR and sequence-based analyses of the serine-aspartate repeat region of sdrG (Fbe) and the repeat region of the accumulation-associated protein gene (aap) were evaluated for the ability to discriminate among previously well-characterized S. epidermidis clinical isolates. Forty-eight strains were investigated, with sdrG found in 100% and aap found in 79% of all strains tested. Both genes demonstrated PCR product size and nucleotide sequence variation. Each system by itself gave an index of discrimination similar in value to that of MLST (0.924 and 0.953 compared to 0.96), but discrimination was further improved when combinations of the three systems were used. We conclude that typing systems using amino acid and nucleotide repeat regions of the S. epidermidis surface proteins SdrG and Aap show promise as typing tools and should be investigated using a larger panel of clinically relevant isolates.
PMCID: PMC1829099  PMID: 17202277
6.  Evolutionary Genetics of the Accessory Gene Regulator (agr) Locus in Staphylococcus aureus† 
Journal of Bacteriology  2005;187(24):8312-8321.
The accessory gene regulator (agr) locus influences the expression of many virulence genes in the human pathogen Staphylococcus aureus. Four allelic groups of agr, which generally inhibit the regulatory activity of each other, have been identified within the species. Interference in virulence gene expression caused by different agr groups has been suggested to be a mechanism for isolating bacterial populations and a fundamental basis for subdividing the species. To test the hypothesis that the species is phylogenetically structured according to agr groups, we mapped agr groups onto a clone phylogeny inferred from partial sequences of 14 genes from 27 genetically diverse strains. Shimodaira-Hasegawa and parametric bootstrap tests rejected the hypotheses that the species is subdivided into three or five monophyletic agr groups but failed to reject the hypothesis that the species is subdivided into two groups that each consist of multiple clonal complexes and multiple agr groups. Additional evidence for agr recombination is found from clustered polymorphisms in complete agr sequences. However, agr recombination has not occurred frequently or randomly through time, because the topology and branch lengths of the clone phylogeny are reflected within each agr group. To account for these observations, we propose a new evolutionary model that involves a genetically polymorphic ancestral population of S. aureus that horizontally transferred agr groups between two subspecies groups near the time that these subspecies groups diverged.
PMCID: PMC1317016  PMID: 16321935

Results 1-6 (6)