Dimethyl sulfoxide enhances effectiveness of skin antiseptics and reduces contamination rates of blood cultures.

Effective skin antisepsis is of central importance in the prevention of wound infections, colonization of medical devices, and nosocomial transmission of microorganisms. Current antiseptics have a suboptimal efficacy resulting in substantial infectious morbidity, mortality, and increased health care costs. Here, we introduce an in vitro method for antiseptic testing and a novel alcohol-based antiseptic containing 4 to 5% of the polar aprotic solvent dimethyl sulfoxide (DMSO). The DMSO-containing antiseptic resulted in a 1- to 2-log enhanced killing of Staphylococcus epidermidis and other microbes in vitro compared to the same antiseptic without DMSO. In a prospective clinical validation, blood culture contamination rates were reduced from 3.04% for 70% isopropanol-1% iodine (control antiseptic) to 1.04% for 70% isopropanol-1% iodine-5% DMSO (P < 0.01). Our results predict that improved skin antisepsis is possible using new formulations of antiseptics containing strongly polarized but nonionizing (polar aprotic) solvents.

Topical adjuvants incompletely remove adherent Staphylococcus aureus from implant materials.

Adjuvant treatments including Betadine, Dakin's solution (sodium hypochlorite), or hydrogen peroxide (H2 O2 ) have been attempted to eradicate prosthetic joint infection caused by biofilm or intracellular bacteria. The purpose of this study was to evaluate the in vitro abilities of chemical adjuvants to decrease Staphylococcus aureus (S. aureus) biofilm presence on orthopaedic implant grade materials, including titanium, stainless steel, and cobalt chrome. S. aureus biofilms were grown for 48 h and evaluated for baseline colony forming units/centimeter squared (CFU/cm2 ) and compared to treatments with Betadine, Dakin's solution, H2 O2 , or 1% chlorine dioxide (ClO2 ). Control discs (n = 18) across all metals had an average of 4.2 × 107 CFU/cm2 . All treatments had statistically significant reductions in CFU/cm2 when compared to respective control discs (p < 0.05). For all metals combined, the most efficacious treatments were Betadine and H2 O2 , with an average 98% and 97% CFU/cm2 reduction, respectively. There were no significant differences between reductions seen with Betadine and H2 O2 , but both groups had statistically greater reductions than Dakin's solution and ClO2 . There was no change in antibiotic resistance patterns after treatment. Analysis of S. aureus biofilms demonstrated a statistically significant reduction in biofilm after a five-minute treatment with the modalities, with an average two log reduction in CFU/cm2 . Statement of clinical significance: While statistically significant reductions in CFU/cm2 were accomplished with chemical adjuvant treatments, the overall concentration of bacteria never fell below 105 CFU/cm2 , leading to questionable clinical significance. Further techniques to eradicate biofilm should be investigated. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1599-1604, 2018.

Unique Footprint in the scl1.3 Locus Affects Adhesion and Biofilm Formation of the Invasive M3-Type Group A Streptococcus.

The streptococcal collagen-like proteins 1 and 2 (Scl1 and Scl2) are major surface adhesins that are ubiquitous among group A Streptococcus (GAS). Invasive M3-type strains, however, have evolved two unique conserved features in the scl1 locus: (i) an IS1548 element insertion in the scl1 promoter region and (ii) a nonsense mutation within the scl1 coding sequence. The scl1 transcript is drastically reduced in M3-type GAS, contrasting with a high transcription level of scl1 allele in invasive M1-type GAS. This leads to a lack of Scl1 expression in M3 strains. In contrast, while scl2 transcription and Scl2 production are elevated in M3 strains, M1 GAS lack Scl2 surface expression. M3-type strains were shown to have reduced biofilm formation on inanimate surfaces coated with cellular fibronectin and laminin, and in human skin equivalents. Repair of the nonsense mutation and restoration of Scl1 expression on M3-GAS cells, restores biofilm formation on cellular fibronectin and laminin coatings. Inactivation of scl1 in biofilm-capable M28 and M41 strains results in larger skin lesions in a mouse model, indicating that lack of Scl1 adhesin promotes bacterial spread over localized infection. These studies suggest the uniquely evolved scl1 locus in the M3-type strains, which prevents surface expression of the major Scl1 adhesin, contributed to the emergence of the invasive M3-type strains. Furthermore these studies provide insight into the molecular mechanisms mediating colonization, biofilm formation, and pathogenesis of group A streptococci.

Comparison of immune response to the influenza vaccine in obese and nonobese healthcare workers.

OBJECTIVE: To determine whether there is a difference in antibody titers and functionality after receipt of the influenza vaccine for obese versus nonobese healthcare workers (HCW). DESIGN: Prospective observational study. SETTING: Tertiary medical center. PARTICIPANTS: Healthcare workers. METHODS Baseline influenza antibody titers for obese and nonobese HCW were recorded during the hospital's 2011 annual influenza vaccination day and follow-up antibody titers were measured 4 weeks later. Antibodies were measured using the hemagglutination inhibition assay and functionality was measured using the micro-neutralization method. RESULTS: Of 200 initial HCWs, 190 completed the study (97 obese and 93 nonobese). Seroprotection after immunization was not significantly different for nonobese compared with obese HCW for each strain (influenza A [H1N1], 99% and 99%; influenza A [H3N2], 100% and 99%; and influenza B, 67% and 71%, respectively) All geometric mean titers measured by micro-neutralization showed statistically significant increases in activity. In comparison, there was no difference in the 4-fold increase in H1N1 or B titers. There was a significant difference in the 4-fold increase of H3N2 titers between the nonobese and obese HCWs (82/93 [88%] vs 64/97 [66%], P=.003) In an ad hoc analysis we found that obese HCWs had a statistically greater number of 4-fold decreases in titers with H1N1 and H3N2. CONCLUSIONS: There was no significant difference in protection from influenza between obese and nonobese HCWs after immunization.