Greenwood‐Quaintance, Kerryl E.

Mini We compared the sensitivity and specificity of peri-implant tissue culture to the vortexing–sonication technique for the diagnosis of spinal implant infection (SII). Lower thresholds of sonicate fluid culture positivity showed increased sensitivity with maintained specificity. We recommend a threshold of 20 CFU/10 mL for sonicate culture positivity for the diagnosis of SII. Study Design. This is a retrospective study comparing the diagnosis of spinal implant infection (SII) by peri-implant tissue culture to vortexing–sonication of retrieved spinal implants. Objective. We hypothesized that vortexing–sonication would be more sensitive than peri-implant tissue culture. Summary of Background Data. We previously showed implant vortexing–sonication followed by culture to be more sensitive than standard peri-implant tissue culture for diagnosing of SII. In this follow-up study, we analyzed the largest sample size available in the literature to compare these two culture methods and evaluated thresholds for positivity for sonicate fluid for SII diagnosis. Methods. We compared peri-implant tissue culture to the vortexing–sonication technique which samples bacterial biofilm on the surface of retrieved spinal implants. We evaluated different thresholds for sonicate fluid positivity and assessed the sensitivity and specificity of the two culture methods for the diagnosis of SII. Results. A total of 152 patients were studied. With more than 100 colony forming units (CFU)/10 mL as a threshold for sonicate fluid culture positivity, there were 46 patients with SII. The sensitivities of peri-implant tissue and sonicate fluid culture were 65.2% and 79.6%; the specificities were 88.7% and 93.4%, respectively. With more than 50 CFU/10 mL as a threshold, there were 50 patients with SII. The sensitivities of peri-implant tissue and sonicate fluid culture were 68.0% and 76.0%; the specificities were 92.2% for both methods. Finally, with more than or equal to 20 CFU/10 mL as a threshold, there were 52 patients with SII. The sensitivities of peri-implant tissue and sonicate fluid culture were 69.2% and 82.7%; the specificities were 94.0% and 92.0%, respectively. Conclusion. Implant sonication followed by culture is a sensitive and specific method for the diagnosis of SII. Lower thresholds for defining sonicate fluid culture positivity allow for increased sensitivity with a minimal decrease in specificity, enhancing the clinical utility of implant sonication. Level of Evidence: 4

The antibiofilm activity of a hydrogen peroxide-generating electrochemical scaffold (e-scaffold) was determined against mono- and trispecies biofilms of methicillin-resistant Staphylococcus aureus , multidrug-resistant Pseudomonas aeruginosa , and Candida albicans . Significant time-dependent decreases were found in the overall CFU of biofilms of all three monospecies and the trispecies forms. Confocal laser scanning microscopy showed dramatic reductions in fluorescence intensities of biofilm matrix protein and polysaccharide components of e-scaffold-treated biofilms.

Metagenomic shotgun sequencing for the identification of pathogens is being increasingly utilized as a diagnostic method. Interpretation of large and complicated data sets is a significant challenge, for which multiple commercial tools have been developed. Three commercial metagenomic shotgun sequencing tools, CosmosID, One Codex, and IDbyDNA, were compared to determine whether they result in similar interpretations of the same sequencing data.

The worldwide spread of multidrug-resistant Enterobacterales is a serious threat to public health. Here, we compared the MICs of plazomicin, amikacin, gentamicin, and tobramycin against 303 multinational multidrug-resistant Gram-negative bacilli. We followed Clinical and Laboratory Standards Institute (CLSI) guidelines and applied CLSI breakpoints as well as those of the European Committee on Antimicrobial Susceptibility Testing (EUCAST) for amikacin, gentamicin, and tobramycin and of the U.S.

Abstract Background We recently demonstrated that 16S rRNA PCR/sequencing performed on biofilms dislodged from extracted CIEDs into a salt solution—referred to as “sonicate fluid’ (SF)—may be used to detect pathogens in culture-negative CIED infection (Clinical Infectious Diseases, ciz266, doi:10.1093/cid/ciz266). The method we described included a DNA extraction/purification step, which can be time consuming and costly. Here, we evaluated an extraction-free approach to 16S rRNA gene PCR/sequencing. Methods 28 SF samples derived from explanted clinically-infected CIEDs were tested. Cases were categorized as “culture-positive” (C-P) if ≥20 cfu/10 mL were recovered, and as “culture-negative” (C-N), if <20 cfu/10 mL were detected in SF culture. The extraction-free method consisted of a single step of lysis at 1,000 rpm, 95°C for 5 minutes using an Eppendorf ThermoMixer®. DNA extraction (the comparator method) was performed using the ZymoBIOMICSTM Kit with modifications. Samples were processed using both methods, followed by amplification of the 16S rRNA gene and bidirectional Sanger sequencing. Crossing points (CPs) generated by the two approaches were compared. Organisms detected by the two PCR methods were compared with those detected with culture. Results Of the 28 samples tested, 13 were C-N and 15 C-P. The extraction-free method generated an amplicon in 13/15 C-P cases, with CPs ranging from 26 to 36 cycles vs. 100% (15/15) detected with the DNA extraction method and Cps of 19 to 32. Usable sequence length for the extraction-free method was of 359 (interquartile range, 307–390) vs. 390 (interquartile range, 308–396) base pairs with DNA extraction. Genus-level concordance between bacteria detected by culture in C-P samples and those found using the extraction-free and extraction methods was 92% (12/13) and 93% (14/15), respectively. Bacteria were detected by the extraction method in 2/13 C-N specimens, with none detected with an extraction-free method. Conclusion The described extraction-free method may be suitable for testing SF derived from CIEDs using 16S rRNA gene PCR/sequencing, saving time and cost. More studies are needed to establish clear cutoffs for interpretation of results and to assess for PCR inhibitors in the studied specimen-type. Disclosures Robin Patel, MD, ASM and IDSA: Other Financial or Material Support, Travel reimbursement, editor’s stipends; CD Diagnostics, Merck, Hutchison Biofilm Medical Solutions, Accelerate Diagnostics, ContraFect, TenNor Therapeutics Limited, Shionogi: Grant/Research Support; Curetis, Specific Technologies, NextGen Diagnostics, PathoQuest, Qvella: Consultant; NBME, Up-to-Date, the Infectious Diseases Board Review Course: Honorarium recipient, Other Financial or Material Support; Patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic, and a patent on an anti-biofilm substance issued: Other Financial or Material Support, Patents.

The in vitro activities of rifampin, rifabutin, rifapentine, and rifaximin were tested against 200 periprosthetic joint infection (PJI)-associated staphylococci. Seven rifampin-resistant isolates had MICs of ≥4 μg/ml. Three isolates had rifampin MICs of 0.25 to 1 μg/ml and harbored an Asp471Gly RpoB variant, suggesting that the CLSI rifampin-susceptible staphylococcal breakpoint of ≤1 μg/ml may be too high.

Bacteriophage-derived lysins are being developed as anti-infective agents. In an acute osteomyelitis methicillin-resistant Staphylococcus aureus (MRSA) model, rats receiving no treatment or treatment with daptomycin, exebacase (CF-301), or daptomycin plus exebacase had means of 5.13, 4.09, 4.65, and 3.57 log 10 CFU/gram of bone, respectively.

Abstract Background Sonicate fluid (SF), a solution derived from vortexing and sonication of explanted cardiovascular implantable electronic devices (CIEDs), is a higher-yield specimen compared with swabs or tissues for culture-based detection of microorganisms associated with CIED infection. Despite this, SF culture fails to identify a causative organism in ~50% of cases. We aimed to evaluate the diagnostic performance of 16S ribosomal RNA gene (rRNA) polymerase chain reaction (PCR)/sequencing of SF and compare it with that of SF culture. Methods We identified 322 SF specimens from extracted CIEDs and reviewed clinical data for each patient. Subjects were classified as having or not having CIED infection. Cases were subcategorized as culture negative if no significant growth was reported from SF cultures and as culture positive if an organism was detected above predefined thresholds. 16S rRNA PCR/sequencing was performed, with the organisms identified reported according to Clinical and Laboratory Standards Institute guidelines for sequence data interpretation. Results A total of 278 SF samples corresponded to infected cases, of which 160 were culture positive and 118 culture negative. The remaining 44 were from noninfected cases, of which 2 were culture positive. Compared with SF culture, the sensitivity of 16S rRNA PCR/sequencing was higher (64% vs 57.5%, P = .003). 16S rRNA PCR/sequencing detected a potential pathogen in 28 of 118 culture-negative cases, identifying staphylococci in the majority (18/28). Conclusions 16S rRNA PCR/sequencing has higher sensitivity to detect bacteria in SF from extracted CIEDs than does SF culture.

We previously demonstrated that shotgun metagenomic sequencing can detect bacteria in sonicate fluid, providing a diagnosis of prosthetic joint infection (PJI). A limitation of the approach that we used is that data analysis was time-consuming and specialized bioinformatics expertise was required, both of which are barriers to routine clinical use.