Human Colon Cancer-Derived Clostridioides difficile Strains Drive Colonic Tumorigenesis in Mice.

Defining the complex role of the microbiome in colorectal cancer and the discovery of novel, protumorigenic microbes are areas of active investigation. In the present study, culturing and reassociation experiments revealed that toxigenic strains of Clostridioides difficile drove the tumorigenic phenotype of a subset of colorectal cancer patient-derived mucosal slurries in germ-free ApcMin/+ mice. Tumorigenesis was dependent on the C. difficile toxin TcdB and was associated with induction of Wnt signaling, reactive oxygen species, and protumorigenic mucosal immune responses marked by the infiltration of activated myeloid cells and IL17-producing lymphoid and innate lymphoid cell subsets. These findings suggest that chronic colonization with toxigenic C. difficile is a potential driver of colorectal cancer in patients. SIGNIFICANCE: Colorectal cancer is a leading cause of cancer and cancer-related deaths worldwide, with a multifactorial etiology that likely includes procarcinogenic bacteria. Using human colon cancer specimens, culturing, and murine models, we demonstrate that chronic infection with the enteric pathogen C. difficile is a previously unrecognized contributor to colonic tumorigenesis. See related commentary by Jain and Dudeja, p. 1838. This article is highlighted in the In This Issue feature, p. 1825.

Progressive Development of Cefiderocol Resistance in Escherichia coli During Therapy is Associated With an Increase in blaNDM-5 Copy Number and Gene Expression.

BACKGROUND: As cefiderocol is increasingly being prescribed in clinical practice, it is critical that we understand key mechanisms contributing to acquired resistance to this agent. METHODS: We describe a patient with acute lymphoblastic leukemia and a New Delhi metallo-ß-lactamase (NDM)-5-producing Escherichia coli intra-abdominal infection in whom resistance to cefiderocol evolved approximately 2 weeks after the start of treatment. Through whole-genome sequencing (WGS), messenger RNA expression studies, and ethylenediaminetetraacetic acid inhibition analysis, we investigated the role of increased NDM-5 production and genetic mutations contributing to the development of cefiderocol resistance, using 5 sequential clinical E. coli isolates obtained from the patient. RESULTS: In all 5 isolates, blaNDM-5 genes were identified. The minimum inhibitory concentrations for cefiderocol were 2, 4, and >32 µg/mL for isolates 1-2, 3, and 4-5, respectively. WGS showed that isolates 1-3 contained a single copy of the blaNDM-5 gene, whereas isolates 4 and 5 had 5 and 10 copies of the blaNDM-5 gene, respectively, on an IncFIA/FIB/IncFII plasmid. These findings were correlated with those of blaNDM-5 messenger RNA expression analysis, in which isolates 4 and 5 expressed blaNDM-5 1.7- and 2.8-fold, respectively, compared to, isolate 1. Synergy testing with the combination of ceftazidime-avibactam and aztreonam demonstrated expansion of the zone of inhibition between the disks for all isolates. The patient was successfully treated with this combination and remained infection free 1 year later. CONCLUSIONS: The findings in our patient suggest that increased copy numbers of blaNDM genes through translocation events are used by Enterobacterales to evade cefiderocol-mediated cell death. The frequency of increased blaNDM-5 expression in contributing to cefiderocol resistance needs investigation.

Is Piperacillin-Tazobactam Effective for the Treatment of Pyelonephritis Caused by Extended-Spectrum ß-Lactamase-Producing Organisms?

BACKGROUND: Limited data exist regarding the efficacy of piperacillin-tazobactam (TZP) for the management of nonbacteremic pyelonephritis caused by extended-spectrum ß-lactamase (ESBL)-producing organisms. METHODS: We conducted a multicenter observational study comparing clinical outcomes of adults hospitalized with ESBL-producing pyelonephritis who were receiving TZP versus carbapenems, using an inverse probability of treatment weighted propensity score analysis. Patients were eligible for inclusion if all of the following criteria were met: (1) urine cultures growing Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, or Proteus mirabilis at ≥50 000 colony-forming units/mL; (2) identification of an ESBL gene; (3) pyuria (≥10 white blood cells per high powered field in the urine); and (4) dysuria and fever plus at least 1 of the following symptoms: emesis, rigors, hypotension, or flank pain. RESULTS: There were 186 patients included in the propensity score-weighted cohort; 45 (24%) received TZP and 141 (76%) received a carbapenem. Of these 186 patients, 27% were admitted to the intensive care unit, 48% were immunocompromised, and 45% had underlying urologic abnormalities. There were no differences between the 2 groups in the proportion of patients (20% vs 25%) with recurrent cystitis or pyelonephritis with the same ESBL-producing organism within 30 days (odds ratio, 0.75; 95% confidence interval, .31-1.81; P = .52). There were no differences in the resolution of clinical symptoms by Day 7 or in 30-day mortality. There was 1 (2%) patient in the TZP arm and 11 (8%) patients in the carbapenem arm who had incident carbapenem-resistant organisms isolated within 30 days (P = .09). CONCLUSIONS: TZP may be a reasonable alternative to carbapenems for the management of ESBL-producing pyelonephritis and may mitigate the risk of emergence of carbapenem-resistant organisms, compared with carbapenem therapy.

Transmission and clearance of potential procarcinogenic bacteria during fecal microbiota transplantation for recurrent Clostridioides difficile.

BACKGROUNDFecal microbiota transplantation (FMT) is an effective treatment for recurrent Clostridioides difficile infection (rCDI) in adults and children, but donor stool samples are currently screened for only a limited number of potential pathogens. We sought to determine whether putative procarcinogenic bacteria (enterotoxigenic Bacteroides fragilis, Fusobacterium nucleatum, and Escherichia coli harboring the colibactin toxin) could be durably transmitted from donors to patients during FMT.METHODSStool samples were collected from 11 pediatric rCDI patients and their respective FMT donors prior to FMT as well as from the patients at 2-10 weeks, 10-20 weeks, and 6 months after FMT. Bacterial virulence factors in stool DNA extracts and stool cultures were measured by quantitative PCR: Bacteroides fragilis toxin (bft), Fusobacterium adhesin A (fadA), and Escherichia coli colibactin (clbB).RESULTSFour of 11 patients demonstrated sustained acquisition of a procarcinogenic bacteria. Whole genome sequencing was performed on colony isolates from one of these donor/recipient pairs and demonstrated that clbB+ E. coli strains present in the recipient after FMT were identical to a strain present in the donor, confirming strain transmission. Conversely, 2 patients exhibited clearance of procarcinogenic bacteria following FMT from a negative donor.CONCLUSIONBoth durable transmission and clearance of procarcinogenic bacteria occurred following FMT, suggesting that additional studies on appropriate screening measures for FMT donors and the long-term consequences and/or benefits of FMT are warranted.FUNDINGCrohn's & Colitis Foundation, the Bloomberg~Kimmel Institute for Cancer Immunotherapy at Johns Hopkins University School of Medicine, the National Cancer Institute, and the Canadian Institutes of Health Research.

Multicenter Clinical Validation of the Molecular BD Max Enteric Viral Panel for Detection of Enteric Pathogens.

The conventional methodology for gastrointestinal pathogen detection remains time-consuming, expensive, and of limited sensitivity. The objective of this study was to evaluate the performance of the BD Max enteric viral panel (Max EVP) assay for identification of viral pathogens in stool specimens from individuals with symptoms of acute gastroenteritis, enteritis, or colitis. Prospective and archival stool specimens from adult and pediatric patients with diarrhea were collected in Cary-Blair medium or unpreserved containers. The results for specimens tested by the Max EVP (on the BD Max platform) were compared to those obtained by the reference method (alternate PCR assays, followed by bidirectional sequencing). Positive percent agreement (PPA) and negative percent agreement (NPA) were calculated. A total of 2,239 specimens were collected, with 2,148 being included for analysis. In this population, 39.6% of specimens were from outpatients, 42.1% were from patients <21 years old, and 49.7% were from females. Prevalence rates for prospective specimens were 7.3%, 4.5%, 3.5%, 2.4%, and 1.2% for norovirus, sapovirus, astrovirus, rotavirus, and adenovirus, respectively. PPA was 92.8%, 84.9%, 93.0%, 100%, and 95.6%, for norovirus, sapovirus, astrovirus, rotavirus, and adenovirus, respectively. NPA was ≥99.4% for all targets. In conjunction with the clinical presentation, laboratory findings, and epidemiological information, the Max EVP assay is effective for the differential diagnosis of enteric disease caused by norovirus, sapovirus, astrovirus, rotavirus, and adenovirus. This assay can be used individually for patients at high risk for a viral enteropathogen (e.g., in outbreak settings) or as an adjunct to other enteric bacterial panels.

Identification of infectious organisms in cytopathology: A review of ancillary diagnostic techniques.

Cytology samples obtained from exfoliative sources and fine-needle aspiration (FNA) procedures can all be used to detect microorganisms and/or the associated cytopathologic effects (CPE) caused by an infection. There are many advantages to utilizing cytology samples as an adjunct to routine microbiology laboratory methods. For example, cytology samples can be obtained by non-invasive and minimally invasive techniques, and interpretation is affordable, accurate, and fast. Furthermore, routine cytology stains, including the Papanicolaou (Pap) and the Diff-Quik (DQ) stains, can adequately identify a number of microorganisms. Finally, material obtained by these procedures can also be used for cytologic ancillary testing, microbiology culture, and molecular studies. Currently, there are a variety of ancillary diagnostic techniques that are routinely utilized in the cytopathology laboratory. Additionally, the increasing utilization of molecular-based, diagnostic techniques on fluid specimens, as well as FFPE material, is expanding the role of cytopathology for infectious disease diagnostics. In this review, we provide an overview of the most practical ancillary techniques commonly used to identify microorganisms on cytology specimens.

Mycobacterium arupense flexor tenosynovitis: case report and review of antimicrobial susceptibility profiles for 40 clinical isolates.

We describe a case of chronic tenosynovitis in the hand of a 58-year-old cattle farmer. Surgical biopsy specimens grew Mycobacterium arupense. The patient responded to surgery and antimicrobial therapy based on in vitro susceptibility testing. The antimicrobial susceptibility profiles of the isolate from this patient and 39 additional clinical isolates are presented.

Development and validation of rapid use scope test strips to determine the efficacy of manual cleaning for flexible endoscope channels.

BACKGROUND: Cleaning of flexible endoscopes is most commonly performed using manual methods that are often performed inadequately. The aim of this study was to validate the sample collection protocol and the Rapid Use Scope Test (RUST) and then assess its usefulness in clinical use. METHODS: The benchmarks for adequate cleaning were protein <6.4 µg/cm(2), hemoglobin <2.2 µg/cm(2), and carbohydrate <1.2 µg/cm(2). Sample collection consisted of flushing 10 mL of sterile reverse osmosis water through the suction-biopsy port to the distal end. Validation of the RUST audit tool included simulated-use and in-use testing in 43 endoscopy clinics across Canada. RESULTS: Simulated-use testing validated that improperly cleaned endoscopes that exceeded the cleaning benchmarks would be flagged by the RUST test. The clinical-use study indicated that 96.6% of 1,489 scope channels tested were RUST negative; however, 19% and 12% of elevator guide-wire channels and endoscopic retrograde colangiopancreatography channels, respectively, exceeded the benchmarks. The survey indicated that reprocessing personnel valued a rapid audit tool for assessing compliance with manual cleaning. CONCLUSION: The validated RUST test provides health care users with a rapid audit tool for manual cleaning that can be integrated into the quality program in endoscopy.