How to use direct microscopy to diagnose fungal infections (2023)

section excerpts


Fast and proper diagnosis of fungal infections is a challenge, especially in immunocompromised hosts [1]. Clinical symptoms are non-specific, fungal colonization is difficult to distinguish from fungal diseases, especially when it comes to non-sterile body samples such as sputum [2]. Blood cultures are usually negative (molds) and generally most patients cannot undergo invasive diagnostic procedures [3]. The question "what is the best specimen for

Why should we choose direct microscopy?

Culture and microscopic examination remain the “gold standard” but may be insensitive and depend on the patient population and sample being tested [1]. As a consequence, the use of antigen and molecular methods in the diagnosis of fungal infections is increasing [5]. In the era of molecular diagnostics, culture and, to a greater extent, microscopy are no longer used to diagnose fungi. Without a doubt, modern tools are of great importance, but nevertheless they are also diverse

What are the best direct microscopy methods?

Several different dyes and techniques are used to detect fungi in clinical specimens [12]. Clinical microbiology laboratories routinely use aqueous potassium hydroxide (KOH), Indian ink, fluorescent dyes including decalfluoride white.TM(CFW), Uvitex 2B lub BlancophorTMand the Gram method for direct examination [4, 13]. Each method has its advantages and disadvantages, which are listed in Table 1. Samples should first be examined for areas of necrosis, purulent, bloody, or caseous; these are the most

Head-to-head: what is the lowest common denominator?

As a group, fungi show great diversity and polymorphism, as exemplified by the different morphologies and structures observed in pathological tissues. Therefore, the detection of fungal elements, e.g. in a lung biopsy, confirms the symptoms of infection, but does not allow for the identification of the genus or species [2, 4]. Recognition of specific structures can only provide a possible fungal pathogen under certain circumstances. Typically, the morphological features visible under the microscope are varied and

What samples should be used for direct testing?

The immediate direct methods of examination depend on the type of sample that reveals the mass pathology and allows you to identify the fungus. Selection of appropriate slides for microscopy is based on clinical examination and consideration of the fungal pathogen most likely to cause such infection [1, 4, 13, 16]. In this case, the most important step is to take samples whenever possible from sites of infection; in addition, all primarily sterile samples taken from suspected patients

What are the pitfalls? From false positives to operator errors

Successful detection of fungal elements in any sample depends greatly on the experience of the researcher, the anatomical site, the amount of sample, the site of pathology, and finally, careful sample preparation. For example, cerebrospinal fluid (CSF) requires centrifugation to concentrate fungi [4]. The fungi are then larger than the bacteria, but are usually present in smaller numbers and in groups [4], so it is necessary to test different parts of the preparation. Moreover, there is

Best practice recommendations for reporting mushroom elements

Depending on the specimen and type of infection, different microscopic morphologies may occur and should be interpreted with caution. The first step is to ensure the suitability and quality of the sample material and to select the appropriate method for detecting the suspected fungal pathogen (see Table 3 and Table 1 for selection of clinical specimens and appropriate staining methods). Reporting of results should include the following fungal morphologies: whether the yeast is small or

Final remarks

Microscopy is an important test and specimens taken from patients suspected of having a fungal infection should be handled with great care. The main pillars should be considered.

  • 1.

    If possible, samples should be taken from infected body sites.

  • 2.

    Specimens taken from infected or primarily sterile body sites should be subjected to fungal microscopy (along with cultured and non-cultured methods).

  • 3.

    Any positive elements of mushrooms should be described based on the morphology of the mushrooms. How

Transparency Statement

The authors declare the following competing interests: MK and SS have no competing interests to declare. CLF reports financial support from Gilead Sciences and Astellas Pharma, received consulting fees or payments/fees for lectures, presentations, educational events from Gilead Sciences, Merck Sharp and Dohme, Pfizer, BioMerieux, F2G, Immy, and received support to attend Gilead Meetings and/or science trips.

Original Contributions

All authors contributed equally to the concept and execution of the review.

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    stuffed nocardiais an opportunistic pathogen that mainly causes pneumonia in immunocompromised patients, complicated in nearly a third of cases by a thick-walled, multi-site brain abscess that causes significant morbidity and mortality. This review aims to evaluate the optimal treatment strategynorthern.stuffingbrain abscess

    Case report. The Medline database was used to conduct a systematic review from inception to January 2020 for articles in English onnorthern.stuffingbrain abscess according to PRISMA guidelines.

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    Urgent multimodal MRI is necessary when there is a clinical suspicion of cerebral nocardiosis. In the case of single or multiple small brain abscesses, microbiological documentation of the puncture of lesions resembling visceral tumors can be obtained. For a large or symptomatic brain abscess, aggressive surgical excision appears to be a reliable option and may be preferred to needle aspiration. Then, long-term antibiotic therapy with co-trimoxazole is necessary.

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    In 2017-2019, we collected prescriptions from outpatient visits from 269 Chinese PHFs in 31 cities located in 6 provinces. Conditions resulting in the use of antibiotics were classified as appropriate, potentially appropriate and unsuitable using a well-established classification method. We then assessed the magnitude, adequacy, and costs of antibiotic prescriptions, overall and by antibiotic classification group, diagnostic categories, and patient characteristics.

    Of the total of 209,662 eligible antibiotic prescriptions, 147,758 (70.5%) were inappropriate, representing 66.8% ($558.0/$835.3K) of antibiotic costs. Upper respiratory tract infections, acute bronchitis and non-infectious gastroenteritis were responsible for 68.9% (101,744/147,758) of inappropriate antibiotic prescriptions. High rates of inappropriate antibiotic prescribing were reported among children aged 0 to 5 years (78.5% (21,049/26,799)) and patients living in economically disadvantaged areas (77.5% (38,430/49,587)). In total, 256,474 single antibiotics were prescribed, of which 82.2% (210,885/256,474) were broad-spectrum antibiotics, including second-generation cephalosporins (15.1% (38,705/256,474)) and third-generation cephalosporins (14.6% (37491/256474) ) ) are the most commonly prescribed subgroups.

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    A total of 206 cases of IE caused by streptococci (n=140, 68%) or enterococci (n=66, 32%) were included. IE occurred in artificial valves in 77 (37%) cases and in intracardiac devices in 28 (14%) cases. The aortic valve was involved in 136 (66%) cases. There were 154 (75%) men, the mean age was 70 ± 14 years, valve surgery was performed in 81/206 (39%) patients, and in-hospital mortality was 8% (17/206). All patients in the MDD group and most of the patients in the non-MDD group received continuous infusion of amoxicillin. Amoxicillin TDM was administered to 114 patients (55.3%) with a mean of 4.7 ± 2.3 measurements per patient, with a mean steady-state plasma concentration of 41.2 ± 19 mg/L, with the majority within ( 82/114, 72%) to the therapeutic target (20-80 mg/l). The mean dose of amoxicillin was lower in patients with MDD (10.0 ± 3.3 g/day) than in patients without MDD (11.3 ± 2.0 g/day) (PAG=0,003).

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    The presence and fate of antimicrobial residues in the environment is of increasing concern. Previous researchers have demonstrated the persistence of residues in soil and water. In addition, antimicrobial resistance is a growing concern, especially for public health, animal health and economic development. This study investigated a low-cost, commercial glucometer as a basis for detecting antimicrobial residues in combination with microorganisms sensitive to these residues. A microbial bioassay based on the metabolic responseGeobacillus stearothermophilus, a sensitive bacterium used to determine antimicrobial residues in food products, measuring changes in glucose levels due to metabolic activity. After optimizing experimental conditions, this detection strategy was tested using bacterial cultures in the presence of colistin, an antibiotic of last resort used to treat humans and animals. GrowthG. stearothermophilusthis was measurable as the change in glucose concentration after 2 to 4 h incubation at 60°C when the LB medium was supplemented with 100 mg/dl glucose. The lowest concentration of colistin measured that resulted in growth inhibition was 1 mg/L colistin, and the lag phase increase resulted in 100 µg/L colistin. To increase the sensitivity of the assay, we then added subinhibitory chloramphenicol to the medium and found that growth inhibition could be achieved with a lower colistin concentration of 8 µg/l. These results provide a promising basis for a future low-cost sensor to identify antimicrobial residues in environmental samples in the field.

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    Evaluation of the available evidence for the clinical effectiveness of individualized optimization of antimicrobial dosing.

    data sources: PubMed, Embase, Web of Science and Cochrane Library databases from database inception to November 11, 2022.

    Published, peer-reviewed, randomized controlled trials.

    Patients ≥18 years of age receiving an antibiotic or antifungal.

    Patients receiving an individualized dose of antibacterial medicine.

    Cochrane tool on the risk of bias in randomized controlled trials.

    The primary outcome was the risk of death. Secondary outcomes included goal achievement, treatment failure, clinical and microbiological cure, length of hospital stay, treatment duration, and adverse events. Effect sizes were combined using a random effects model. Inconsistency tests (I2).

    Ten randomized controlled trials (1241 participants;northern=624 in the individualized antimicrobial group inorthern=617 in the control group). Optimization of individualized dosing of antimicrobial agents was associated with a numerical reduction in mortality (hazard ratio [RR] = 0.86; 95% CI, 0.71-1.05), without reaching statistical significance. In addition, it was associated with significantly higher target achievement rates (RR=1.41; 95% CI, 1.13–1.76) and a significant reduction in treatment failure (RR=0.70; 95% CI, 0.54–0.54). .92). Optimization of individualized antimicrobial dosing was associated with an improvement but not a significant improvement in clinical cure (RR=1.33; 95% CI, 0.94-1.33) and microbiological score (RR=1.25; CI, 1, 00-1.57), and a significant decrease in the risk of nephrotoxicity (RR=0.55; 95% CI, 0.31-0.97).

    This meta-analysis showed that target achievement, treatment failure, and nephrotoxicity were significantly improved in patients who underwent individualized antimicrobial dose optimization. Improvements in mortality, clinical cure or microbiological scores have been demonstrated, although not significant.

© 2023 European Society for Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.


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