Cunningham, Scott A.

Ureaplasma -induced hyperammonemia is a deadly complication affecting around 4% of lung transplant recipients and, to a lesser extent, other solid organ transplant patients. Understanding the underlying mechanisms will inform patient management, potentially decreasing mortality and morbidity. Here, it is shown that uremia is a plausible contributing factor to the pathophysiology of the condition.

In total, 50 Escherichia coli bloodstream isolates from the clinical laboratory and 12 E. coli isolates referred for pulsed-field gel electrophoresis (PFGE) were sequenced, assessed for clonality using core genome multilocus sequence typing (cgMLST), and evaluated for genomic susceptibility predictions using ARESdb. Results of sequence typing using whole-genome sequencing (WGS)-based MLST and sequence type (ST)-specific PCR were identical.

Helicobacter pylori infection is mainly diagnosed noninvasively, with susceptibility testing traditionally requiring endoscopy. Treatment is empirical, with clarithromycin-based triple therapy recommended where resistance rates are below 15%. Rising rates of clarithromycin resistance, resulting in high therapy failure rates, are seen worldwide, but U.S. data are limited.

The taxonomic position of Yersinia kristensenii subsp. rochesterensis and Yersinia occitanica was re-evaluated by genomic analysis. Average nucleotide identity (ANI), digital DNA–DNA hybridization values, and phylogenetic analyses of the type strains indicate that Y. kristensenii subsp. rochesterensis and Y. occitanica are the same genospecies. Additionally, the overall genomic relatedness index (OGRI) values reveal that Y. kristensenii subsp. rochesterensis should be elevated to species status as Yersinia rochesterensis sp. nov.

AbstractBackgroundCurrent approaches in tracking Clostridioides difficile infection (CDI) and individualizing patient management are incompletely defined.MethodsWe recruited 468 subjects with CDI at Mayo Clinic Rochester between May and December 2016 and performed whole-genome sequencing (WGS) on C. difficile isolates from 397. WGS was also performed on isolates from a subset of the subjects at the time of a recurrence of infection. The sequence data were analyzed by determining core genome multilocus sequence type (cgMLST), with isolates grouped by allelic differences and the predicted ribotype.ResultsThere were no correlations between C. difficile isolates based either on cgMLST or ribotype groupings and CDI outcome. An epidemiologic assessment of hospitalized subjects harboring C. difficile isolates with ≤2 allelic differences, based on standard infection prevention and control assessment, revealed no evidence of person-to-person transmission. Interestingly, community-acquired CDI subjects in 40% of groups with ≤2 allelic differences resided within the same zip code. Among 18 subjects clinically classified as having recurrent CDI, WGS revealed 14 with initial and subsequent isolates differing by ≤2 allelic differences, suggesting a relapse of infection with the same initial strain, and 4 with isolates differing by >50 allelic differences, suggesting reinfection. Among the 5 subjects classified as having a reinfection based on the timing of recurrence, 3 had isolates with ≤2 allelic differences between them, suggesting a relapse, and 2 had isolates differing by >50 allelic differences, suggesting reinfection.ConclusionsOur findings point to potential transmission of C. difficile in the community. WGS better differentiates relapse from reinfection than do definitions based on the timing of recurrence.

Abstract Background Sequence type 131 (EC-ST131) is a prevalent cause of extraintestinal Escherichia coli infection, including in neonates, and accounts for a majority of multidrug-resistant strains. Rare reports of neonatal unit outbreaks have emerged, with one linking the source to freshly expressed breast milk (BM) sharing. We report on premature twin girls whose infection was linked to their mother’s contaminated frozen BM. Methods Blood culture isolates were from twin girls born at 24–1/7 weeks’ gestation who developed severe sepsis caused by ampicillin- and gentamicin-resistant E. coli on days 11 (Baby A; died) and 8 (Baby B; survived) of life; both neonates had sterile blood cultures at birth, and received orogastric feeds using frozen BM provided by their mother. Five remaining frozen BM samples predating onset of sepsis were thawed and cultured; E. coli resistant to ampicillin and gentamicin was recovered from 1 collected on day 5 of life. DNA was extracted from cultured isolates using the Zymo Research Quick-DNA™ Fungal/Bacterial Miniprep kit, sequencing libraries prepared (Nextera® XT PE), and sequencing (Illumina MiSeq® with V2 2 X 250 bp chemistry) completed for the 2 blood and 1 BM isolates. Multilocus Sequence Typing (MLST) and core genome MLST (cgMLST) analyses were performed using SeqSphere+, version 5.1.0 (Ridom, Munster, DE) software, with 2513 alleles analyzed for cgMLST. Results The 2 blood and 1 BM isolates were typed as ST131 by MLST and were indistinguishable by cgMLST. Of the 2513 alleles queried, only 263 (10.5%) differed from the ST131 strain SCB34 (figure). Thus, our EC-ST131 cluster isolates belong to the same clonal complex as, but are genetically divergent from, SCB34. In addition to the E. coli described above isolated from a BM sample, all 5 frozen BM samples grew multiple morphotypes of coagulase-negative staphylococci. The mother had acute chorioamnionitis and was treated with intravenous ampicillin, gentamicin, and metronidazole for 48 hours immediately after delivery. Conclusion Despite frozen BM’s persistent antibacterial activity, it is a potential source of multidrug-resistant bacteria for neonates, as evidenced by this report of EC-ST131 neonatal sepsis in premature twins. 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.

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.

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.