sodium-dodecyl-sulfate and Bacteremia

Patient mortality is significantly reduced by rapid identification of bacteria from sterile sites. MALDI-TOF can identify bacteria directly from positive blood cultures and multiple sample preparation methods are available. We evaluated three sample preparation methods and two MALDI-TOF score cut-off values. Positive blood culture bottles with organisms present in Gram stains were prospectively analysed by MALDI-TOF. Three lysis reagents (Saponin, SDS, and SepsiTyper lysis bufer) were applied to each positive culture followed by centrifugation, washing and protein extraction steps. Methods were compared using the McNemar test and 16S rDNA sequencing was used to assess discordant results.. In 144 monomicrobial cultures, using ≥2.000 as the cut-off value, species level identifications were obtained from 69/144 (48%) samples using Saponin, 86/144 (60%) using SDS, and 91/144 (63%) using SepsiTyper. The difference between SDS and SepsiTyper was not statistically significant (P = 0.228). Differences between Saponin and the other two reagents were significant (P < 0.01). Using ≥1.700 plus top three results matching as the cut-off value, species level identifications were obtained from 100/144 (69%) samples using Saponin, 103/144 (72%) using SDS, and 106/144 (74%) using SepsiTyper and there was no statistical difference between the methods. No true discordances between culture and direct MALDI-TOF identification were observed in monomicrobial cultures. In 32 polymicrobial cultures, MALDI-TOF identified one organism in 34-75% of samples depending on the method.. This study demonstrates two inexpensive in-house detergent lysis methods are non-inferior to a commercial kit for analysis of positive blood cultures by direct MALDI-TOF in a clinical diagnostic microbiology laboratory.

Topics: Bacteremia; Bacteria; Bacterial Infections; Bacteriological Techniques; Blood Culture; Blood Grouping and Crossmatching; Centrifugation; Detergents; DNA, Bacterial; Electrophoresis, Capillary; Humans; RNA, Ribosomal, 16S; Saponins; Sodium Dodecyl Sulfate; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

MALDI-ToF MS can be used to identify microorganisms directly from blood cultures. This study compared two methods of sample preparation. Similar levels of genus- (91% vs 90%) and species-level identifications (79% vs 74%) were obtained with differential centrifugation and SDS methods. The SDS method is faster and requires minimal handling.

Topics: Bacteremia; Bacteria; Blood Culture; Humans; Sodium Dodecyl Sulfate; Specimen Handling; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Time Factors

The aim of this study was to evaluate and compare the activity of oral mouthwashes against biofilm forms of MRSA isolated from the oral cavity and the bloodstream.. The time-kill kinetics efficacy of 7 over-the-counter mouthwashes were tested against 28 clinical MRSA biofilm isolates for 0.5, 1 and 2 min.. Treatments of MRSA biofilms formed by oral and bloodstream isolates were not significantly different, with mouthwashes displaying a rapid and modest anti-biofilm effect. None of the biofilm isolates were completely eradicated by the compounds tested, with a maximal killing of only approximately 70% shown by Corsodyl and Peroxyl. Maximum activity of all compounds tested was observed after 0.5 min. Fluorigard showed the poorest overall activity (57% reduction).. MRSA colonize the oral cavity, and are more prevalent in institutionalized persons and the elderly. Over-the-counter mouthwashes are ineffective at killing MRSA biofilms, which has infection control implications.

Topics: Aloe; Anti-Infective Agents, Local; Bacteremia; Bacteriological Techniques; Benzoates; Biofilms; Cetylpyridinium; Chlorhexidine; Drug Combinations; Drug Resistance, Bacterial; Humans; Hydrogen Peroxide; Indicators and Reagents; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Mouth; Mouthwashes; Plant Preparations; Salicylates; Sodium Dodecyl Sulfate; Tea Tree Oil; Terpenes; Tetrazolium Salts; Time Factors; Triclosan

We describe a case of bacteraemia due to an atypical strain of Campylobacter fetus ssp. fetus. Conventional biochemical and phenotypic characterisation was unhelpful but whole cell protein profiles obtained by means of sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) allowed us to identify this strain.

Topics: Bacteremia; Bacterial Proteins; Campylobacter fetus; Campylobacter Infections; Child; Electrophoresis, Polyacrylamide Gel; Humans; Male; Sodium Dodecyl Sulfate; Species Specificity; Surface-Active Agents

Rochalimaea quintana was isolated from the blood of a French human immunodeficiency virus-infected patient with bacillary angiomatosis. The isolate showed the typical growth characteristics of Rochalimaea species and was inert when typical biochemical testing was used. The purpose of the present work was to characterize and compare this new isolate with reference strains of R. quintana, Rochalimaea vinsonii, and Rochalimaea henselae by using immunofluorescence, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Western blot (immunoblot), restriction fragment length polymorphism-PCR of the citrate synthase gene, 16S rRNA gene sequencing, and pulsed-field gel electrophoresis. SDS-PAGE, Western blot, restriction fragment length polymorphism-PCR with TaqI enzyme, and 16S rRNA gene sequencing could differentiate the three Rochalimaea species and allowed characterization of the French isolate as R. quintana. However, identification of the Rochalimaea isolate to the species level was more easily obtained by immunofluorescence with specific murine antisera. Pulsed-field gel electrophoresis allowed differentiation of the French R. quintana isolate from R. quintana Fuller and may serve as an epidemiological tool.

Topics: Adult; AIDS-Related Opportunistic Infections; Angiomatosis, Bacillary; Bacteremia; Bacterial Proteins; Base Sequence; Blotting, Western; Drug Resistance, Microbial; Electrophoresis, Gel, Pulsed-Field; Electrophoresis, Polyacrylamide Gel; Fluorescent Antibody Technique; Genes, Bacterial; Humans; Male; Molecular Sequence Data; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Rickettsia; RNA, Bacterial; RNA, Ribosomal, 16S; Sodium Dodecyl Sulfate; Trench Fever