Nguyen, M Hong

ABSTRACT Medically important pathogenic fungi invade vertebrate tissue and are considered primary when part of their nature life cycle is associated with an animal host and are usually able to infect immunocompetent hosts. Opportunistic fungal pathogens complete their life cycle in environmental habitats or occur as commensals within or on the vertebrate body, but under certain conditions can thrive upon infecting humans. The extent of host damage in opportunistic infections largely depends on the portal and modality of entry as well as on the host’s immune and metabolic status. Diseases caused by primary pathogens and common opportunists, causing the top approximately 80% of fungal diseases [D. W. Denning, Lancet Infect Dis, 24:e428–e438, 2024, https://doi.org/10.1016/S1473-3099(23)00692-8 ], tend to follow a predictive pattern, while those by occasional opportunists are more variable. For this reason, it is recommended that diseases caused by primary pathogens and the common opportunists are named after the etiologic agent, for example, histoplasmosis and aspergillosis, while this should not be done for occasional opportunists that should be named as [causative fungus] [clinical syndrome], for example, Alternaria alternata cutaneous infection. The addition of a descriptor that identifies the location or clinical type of infection is required, as the general name alone may cover widely different clinical syndromes, for example, “rhinocerebral mucormycosis.” A list of major recommended human and animal disease entities (nomenclature) is provided in alignment with their causative agents. Fungal disease names may encompass several genera of etiologic agents, consequently being less susceptible to taxonomic changes of the causative species, for example, mucormycosis covers numerous mucormycetous molds.

ABSTRACT The rapid pace of name changes of medically important fungi is creating challenges for clinical laboratories and clinicians involved in patient care. We describe two sources of name change which have different drivers, at the species versus the genus level. Some suggestions are made here to reduce the number of name changes. We urge taxonomists to provide diagnostic markers of taxonomic novelties. Given the instability of phylogenetic trees due to variable taxon sampling, we advocate to maintain genera at the largest possible size. Reporting of identified species in complexes or series should where possible comprise both the name of the overarching species and that of the molecular sibling, often cryptic species. Because the use of different names for the same species will be unavoidable for many years to come, an open access online database of the names of all medically important fungi, with proper nomenclatural designation and synonymy, is essential. We further recommend that while taxonomic discovery continues, the adaptation of new name changes by clinical laboratories and clinicians be reviewed routinely by a standing committee for validation and stability over time, with reference to an open access database, wherein reasons for changes are listed in a transparent way.

AbstractBackgroundClostridioides difficile infection (CDI) is a significant cause of morbidity and mortality in recipients of solid organ transplant (SOT) or hematopoietic stem cell transplant (HSCT). In retrospective single center analyses, severe disease and relapse are common. We undertook an international, prospective cohort study to estimate the response to physician determined antibiotic treatment for CDI in patients with SOT and HSCT.MethodsAdults with a first episode of CDI within the first 2 years of SOT or HSCT were enrolled. Demographics, comorbidities, and medication history were collected, and over 90 days of follow‐up clinical cure, recurrences, and complications were assessed. Logistic regression was used to study associations of baseline predictors of clinical cure and recurrence. Odds ratios (ORs) and 95% confidence intervals (CIs) are cited.ResultsA total of 132 patients, 81 SOT and 51 HSCT (32 allogeneic), were enrolled with a median age of 56 years; 82 (62%) were males and 128 (97%) were hospitalized at enrollment. One hundred and six (80.3%) were diagnosed by DNA assay. CDI occurred at a median of 20 days post‐transplant (interquartile range, IQR: 6–133). One hundred and eight patients (81.8%) were on proton pump inhibitors; 126 patients (95.5%) received antibiotics within the 6 weeks before CDI. The most common initial CDI treatments prescribed, on or shortly before enrollment, were oral vancomycin alone (50%) and metronidazole alone (36%). Eighty‐three percent (95% CI: 76, 89) of patients had clinical cure; 18% (95% CI: 12, 27) of patients had recurrent CDI; global clinical cure occurred in 65.2%. Of the 11 patients who died, two (1.5% of total) were related to CDI. In multivariable logistic regression analyses, the type of initial treatment was associated with clinical cure (p = .009) and recurrence (p = .014). A history of cytomegalovirus (CMV) after transplant was associated with increased risk of recurrence (44% with versus 13% without CMV history; OR: 5.7, 95% CI: 1.5, 21.3; p = .01).ConclusionsAmong adults who develop CDI after SOT or HSCT, despite their immunosuppressed state, the percentage with clinical cure was high and the percentage with recurrence was low. Clinical cure and recurrence varied by type of initial treatment, and CMV viremia/disease was associated with an increased risk of recurrence.

Abstract Background CDI is an important cause of morbidity and mortality in SOT and HCT patients (pts). In retrospective single-center analyses, severe disease and relapse were common. We undertook a multicenter prospective observational study to evaluate outcomes of CDI among both SOT and HCT patients. Methods Adults with a first episode of CDI, defined as 3 liquid stools/24 h with the detection of C. difficile toxin in stool, within the first 2 years of SOT or HCT were recruited from 12 centers internationally in the INSIGHT network. At enrollment, demographics, comorbidities, medication histories and outcomes were collected prospectively over 90 days to assess clinical cure, recurrences and complications and to define baseline risk factors for clinical cure and recurrent CDI. Results 132 patients (81 SOT, 51 HCT (32 allogeneic)) were enrolled: median age 56 years, 62.1% were males, 97% were hospitalized. 80.3% were diagnosed by DNA assay. CDI occurred a median of 20 days post transplant (IQR: 6–133). 108 patients were on PPIs. 98.5% were on antibiotics before CDI. 1st line treatment regimen was oral vancomycin in 66 patients (40 SOT, 26 HCT), metronidazole in 48 patients (27 SOT, 21 HCT), both drugs in 14 (10 SOT, 4 HCT), fidaxomicin (3) and linezolid (1). Rejection within 60 days before CDI was uncommon (6.2% SOT) as was GVHD (27.5%). 110 patients (83%, 95% CI: 46–89)) (65 SOT, 45 HCT) had clinical cure; 18% (95% CI: 11–27) had recurrent CDI, 2 were admitted to the ICU due to CDI, 11 (8.3%) died (2 HCT related to CDI). Among baselines variables, only first-line regimen was associated with a higher rate of clinical cure (P = 0.003), most notably for SOT. Factors that did not have a statistically significant negative impact on clinical cure included sex, age > 60, race, country, transplant type, steroids, diabetes, CMV viremia/disease, WBC > 15,000, creatinine > 1.5 mg/dL, or specific antibiotic given prior to CDI. Higher recurrence rates were associated with metronidazole-only regimen (OR: 4.6, 95% CI: 1.6–12.8; P = 0.004) and a history of CMV after transplant (OR: 5.2, 95% CI: 1.7–15.7; P = 0.003). Conclusion Despite their immunosuppressed state, recurrence, ICU admission and mortality occurred in a minority of SOT and HCT with CDI. Initial use of metronidazole and CMV viremia/disease were associated with higher recurrence rates. Disclosures All authors: No reported disclosures.