A dedicated fungal culture medium is useful in the diagnosis of fungemia: a retrospective cross-sectional study

Evaluation of Different Blood Culture Bottles for the Diagnosis of Bloodstream Infections in Patients with HIV

INTRODUCTION

Bloodstream infection (BSI) is a significant factor contributing to hospitalization and high mortality rates among human immunodeficiency virus(HIV)-positive patients. Therefore, the timely detection of this condition is of utmost importance. Blood culture is considered the gold standard for diagnosing BSIs. Currently, BD BACTEC™ Plus Aerobic/F culture bottles and the BD BACTEC™ Myco/F Lytic culture bottles can be used for blood culture. This study aimed to evaluate the efficacy of two different types of culture bottles in diagnosing BSIs in patients with HIV.

METHODS

A retrospective analysis was conducted on HIV-positive patients hospitalized in the Infection Department of Wenzhou Central Hospital between July 2019 and October 2021. A total of 246 pairs of blood samples were included, consisting of an aerobic culture vial and a Myco/F culture vial. Blood culture results and clinical diagnosis were utilized to identify the presence of BSI.

RESULTS

Out of 246 cases, 84 cases had positive blood cultures. Fungal BSIs, particularly Talaromyces marneffei BSIs, were the most prevalent among patients with HIV. The positive rate of Myco/F culture bottles (89.29%) was significantly higher compared with aerobic culture bottles (69.05%; P = 0.001). In the diagnosis of fungal BSIs, the positive rate of Myco/F culture bottles was 88.57%, which was significantly higher than that of aerobic culture bottles (72.86%; P = 0.018). The Myco/F culture bottle has more advantages in diagnosing Talaromyces marneffei BSIs (P=0.028). In addition, mycobacteria were exclusively detected in Myco/F culture bottles.

CONCLUSIONS

Fungal BSIs are the predominant type of infections in HIV-positive patients. Myco/F culture bottles exhibit noteworthy attributes of high positive rate in diagnosing HIV combined with BSI. These advantages are conducive to obtaining accurate culture results and minimizing missed diagnoses.

A Dedicated Mycosis Flask Increases the Likelihood of Identifying Candidemia Sepsis

Introduction: Candidemia is a severe condition associated with high mortality, and fungi are often not covered by empiric antimicrobial regimes for sepsis. Therefore, the shortest possible time to detection of yeast in the blood is of the essence. Materials and methods: We performed a cohort study of blood culture flasks drawn from patients aged 18 or older in the capital region of Denmark. In 2018 a blood cultures set consisted of two aerobic and two anaerobic flasks. This was changed in 2020 to two aerobic, one anaerobic, and one mycosis flask. We used time-to-event statistics to model time to positivity and compared 2018 with 2020; further, we stratified analyses on the blood culture system used (BacTAlert™ vs. BACTEC™) and high-risk vs. low-risk departments. Results: We included 175,416 blood culture sets and 107,077 unique patients. We found an absolute difference in the likelihood of identifying fungi in a blood culture set of 1.2 (95% CI: 0.72; 1.6) pr. 1.000 blood culture sets corresponding to the number needed to treat 853 (617; 1382). In high-risk departments, the absolute difference was profound, whereas it was negligible and statistically non-significant in low-risk departments 5.2 (95% CI: 3.4; 7.1) vs. 0.16 (−0.17; 0.48) pr. 1.000 blood culture sets. Conclusions: We found that including a mycosis flask in a blood culture set increases the likelihood of identifying candidemia. The effect was mainly seen in high-risk departments.

Evaluation of an Antifungal Stewardship Initiative Targeting Micafungin at an Academic Medical Center

Delays in the treatment of proven invasive fungal disease have been shown to be harmful. However, empiric treatment for all patients at risk of infection has not demonstrated benefit. This study evaluates the effects of a micafungin stewardship initiative on the duration of therapy and clinical outcomes at the University of Mississippi Medical Center in Jackson, Mississippi. This single-center quasi-experiment evaluated patients who received micafungin. Adult inpatients who received at least one treatment dose of micafungin in the pre-intervention (1 October 2020 to 30 September 2021) or post-intervention (1 October 2021 to 30 April 2022) groups were included. Patients were placed on micafungin for prophylaxis and those who required definitive micafungin therapy were excluded. An algorithm was used to provide real-time recommendations in order to assess change in the treatment days of micafungin therapy. A total of 282 patients were included (141 pre-group versus 141 post-group). Over 80% of the patients included in the study were in an intensive care unit, and other baseline characteristics were similar. The median number of treatment days with micafungin was 4 [IQR 3-6] in the pre-group and 3 [IQR 2-6] in the post-group (p = 0.005). Other endpoints, such as time to discontinuation or de-escalation, hospital mortality, and hospital length of stay, were not significantly different between the groups. An antifungal stewardship initiative can be an effective way to decrease unnecessary empiric antifungal therapy for patients who are at risk of invasive fugal disease.

Global guideline for the diagnosis and management of rare yeast infections: an initiative of the ECMM in cooperation with ISHAM and ASM

Uncommon, or rare, yeast infections are on the rise given increasing numbers of patients who are immunocompromised or seriously ill. The major pathogens include those of the genera Geotrichum, Saprochaete, Magnusiomyces, and Trichosporon (ie, basidiomycetes) and Kodamaea, Malassezia, Pseudozyma (ie, now Moesziomyces or Dirkmeia), Rhodotorula, Saccharomyces, and Sporobolomyces (ie, ascomycetes). A considered approach to the complex, multidisciplinary management of infections that are caused by these pathogens is essential to optimising patient outcomes; however, management guidelines are either region-specific or require updating. In alignment with the One World-One Guideline initiative to incorporate regional differences, experts from diverse geographical regions analysed publications describing the epidemiology and management of the previously mentioned rare yeasts. This guideline summarises the consensus recommendations with regards to the diagnostic and therapeutic options for patients with these rare yeast infections, with the intent of providing practical assistance in clinical decision making. Because there is less clinical experience of patients with rare yeast infections and studies on these patients were not randomised, nor were groups compared, most recommendations are not robust in their validation but represent insights by use of expert opinions and in-vitro susceptibility results. In this Review, we report the key features of the epidemiology, diagnosis, antifungal susceptibility, and treatment outcomes of patients with Geotrichum, Saprochaete, Magnusiomyces, and Trichosporon spp infections.

Epidemiological Trends of Candidemia and the Impact of Adherence to the Candidemia Guideline: Six-Year Single-Center Experience

This study aimed to investigate the epidemiology of candidemia and evaluate the impact of adherence to the candidemia guideline defined by the European Confederation of Medical Mycology Quality of Clinical Candidemia Management (EQUAL) Candida score. Adult candidemia patients ≥ 19 years diagnosed at a tertiary care hospital in the Republic of Korea from 2013 to 2018 were enrolled (period 1 2013–2015, period 2 2016–2018). There was a total of 223 patients. The annual incidence of candidemia increased from 0.43 to 1.33 cases per 1000 admissions between 2013 and 2018, p < 0.001. A significant increase of fluconazole-resistant C. parapsilosis candidemia was noted in period 2 (35.3%) when compared to period 1 (0.0%), p = 0.020. The 30-day mortality rate was not different between period 1 and 2 (43.5% vs. 48.1%, p = 0.527). Multivariate analysis revealed that a Charlson comorbidity index score ≥ 4, neutropenia, duration of hospital stay ≥ 21 days before candidemia diagnosis, septic shock, mycological failure, and EQUAL Candida score < 15 were significantly associated with 30-day mortality. An increase in the incidence of candidemia and fluconazole resistance in the non-albicans Candida species over time was observed. Disease severity, comorbidities, and lower adherence to the candidemia guideline were associated with mortality.

Critical factors in the recovery of pathogenic microorganisms in blood

BACKGROUND

The critical factors for optimal recovery of microbial pathogens from blood are not only the basis for how we perform blood cultures on a daily basis, but are also important for development of all current blood-culture systems. Because much of this research was conducted and published between 1975 and 2010 there is a general sense that many physicians and scientists may not be familiar with it, but it is critical for performing and interpreting blood cultures.

OBJECTIVES

To review the critical factors in the laboratory recovery and isolation of pathogenic microorganisms in blood.

SOURCES

Literature review of published papers, select reviews and updated guidelines.

CONTENT

This review focuses on the critical factors that affect the recovery isolation of pathogenic microorganisms from individuals with bloodstream infections. Contemporary blood-culture systems, and current methods for blood-culture collection, have been designed to incorporate these critical factors so as to optimize recovery and isolation of pathogens while minimizing contamination.

IMPLICATIONS

It is important for microbiologists and practitioners to understand how and why these critical factors affect current blood-culture practices to improve patient management. Future research should emphasize which of these critical factors will still play a role in the era of molecular diagnostic tests, which will no longer be relevant, and which new critical factors have yet to be defined.