Answer to July 2023 Photo Quiz

Read the full article for the answer.

Report of terbinafine resistant Trichophyton spp. in Italy: Clinical presentations, molecular identification, antifungal susceptibility testing and mutations in the squalene epoxidase gene

BACKGROUND

Numerous reports of resistance to terbinafine in Trichophyton spp. from all over the world are arousing justified attention and concern. Point mutations in the gene that encodes the squalene epoxidase (SQLE) enzyme are responsible for these therapeutic resistances.

OBJECTIVES

Primary objective of the study was to describe first isolates of Trichophyton spp. resistant to terbinafine among the patients treated between September 2019 and June 2022 at the Dermatology Units of Ospedale Maggiore Policlinico and San Bortolo Hospital. Secondary objective was to study the resistance mechanism.

METHODS

Patients with confirmed Trichophyton spp. infection has been treated with systemic and topical terbinafine. Patients were then re-evaluated 12 weeks after the therapy. Patients with incomplete or absent response to terbinafine underwent a new skin scraping for direct mycological examination, new identification of dermatophyte species from culture and MALDI-TOF, molecular species identification, antifungal susceptibility testing and molecular analysis of SQLE gene.

RESULTS

We identified five patients without clinical response to treatment with terbinafine. The DNA sequencing of the ITS region identified one Trichophyton rubrum and four Trichophyton indotineae. The T. rubrum strain showed minimum inhibitory concentration (MIC) (90% growth inhibition) of 4 mg/L for terbinafine. The four T. indotineae strains showed a MICs range of 0.25-4 mg/L for terbinafine. The analysis of the SQLE gene in the T. rubrum strain showed a nucleotide substitution generating a missense mutation (L393F). The SQLE gene sequencing in the T. indotineae strains showed a nucleotide substitution generating a missense mutation (F397L) in two strains, a nucleotide substitution L393S in one strain and a nucleotide substitution F415C in another strain.

CONCLUSIONS

We report the first cases of terbinafine-resistant Trichophyton isolates in the Italian population. Solid antifungal management programs will be needed to promote more responsible use of antimycotics and preserve their therapeutic efficacy to control antifungal resistance.

Yeast Bloodstream Infections in the COVID-19 Patient: A Multicenter Italian Study (FiCoV Study)

Fungemia is a co-infection contributing to the worsening of the critically ill COVID-19 patient. The multicenter Italian observational study FiCoV aims to estimate the frequency of yeast bloodstream infections (BSIs), to describe the factors associated with yeast BSIs in COVID-19 patients hospitalized in 10 hospitals, and to analyze the antifungal susceptibility profiles of the yeasts isolated from blood cultures. The study included all hospitalized adult COVID-19 patients with a yeast BSI; anonymous data was collected from each patient and data about antifungal susceptibility was collected. Yeast BSI occurred in 1.06% of patients, from 0.14% to 3.39% among the 10 participating centers. Patients were mainly admitted to intensive or sub-intensive care units (68.6%), over 60 years of age (73%), with a mean and median time from the hospitalization to fungemia of 29 and 22 days, respectively. Regarding risk factors for fungemia, most patients received corticosteroid therapy during hospitalization (61.8%) and had a comorbidity (25.3% diabetes, 11.5% chronic respiratory disorder, 9.5% cancer, 6% haematological malignancies, 1.4% organ transplantation). Antifungal therapy was administered to 75.6% of patients, mostly echinocandins (64.5%). The fatality rate observed in COVID-19 patients with yeast BSI was significantly higher than that of COVID-19 patients without yeast BSI (45.5% versus 30.5%). Candida parapsilosis (49.8%) and C. albicans (35.2%) were the most fungal species isolated; 72% of C. parapsilosis strains were fluconazole-resistant (range 0-93.2% among the centers). The FiCoV study highlights a high prevalence of Candida BSIs in critically ill COVID-19 patients, especially hospitalized in an intensive care unit, a high fatality rate associated with the fungal co-infection, and the worrying spread of azole-resistant C. parapsilosis.

Environmental and bioclimatic factors influencing yeasts and molds distribution along European shores

The present study employed data collected during the Mycosands survey to investigate the environmental factors influencing yeasts and molds distribution along European shores applying a species distribution modelling approach. Occurrence data were compared to climatic datasets (temperature, precipitation, and solar radiation), soil datasets (chemical and physical properties), and water datasets (temperature, salinity, and chlorophyll-a concentration) downloaded from web databases. Analyses were performed by MaxEnt software. Results suggested a different probability of distribution of yeasts and molds along European shores. Yeasts seem to tolerate low temperatures better during winter than molds and this reflects a higher suitability for the Northern European coasts. This difference is more evident considering suitability in waters. Both distributions of molds and yeasts are influenced by basic soil pH, probably because acidic soils are more favorable to bacterial growth. Soils with high nitrogen concentrations are not suitable for fungal growth, which, in contrast, are optimal for plant growth, favored by this environment. Finally, molds show affinity with soil rich in nickel and yeasts with soils rich in cadmium resulting in a distribution mainly at the mouths of European rivers or lagoons, where these metals accumulate in river sediments.

Fungal diversity in lake and sea beaches of Italy: Relevance to human health

Fungal diseases correlated to beach sand or water have not yet been demonstrated due to the lack of epidemiological studies. This study aims to illustrate the fungal population in beach sands of the two largest Italian lakes and in sands and waters of Mediterranean coasts of Southern Italy to contribute to the identification and assessment of causes of microbiological pollution that might impair bathers health. A great difference was observed between the two lakes, where the total of colony-forming units (CFU) ranged from 33.3 to 1049.9 CFU/g. For coastal sands, the total CFU ranged from 216.7 to 538.8 CFU/g, and for coastal waters the total ranged from 185 to 368.7 CFU/ml. The survey revealed the prevalence of opportunistic pathogenic moulds, mainly Aspergillus spp. (A. niger and A. fumigatus) and Penicillium spp., both in freshwater and costal bathing sites. Dermatophytes and yeasts were not detected in the freshwater sands while they were found at low load in coastal waters (3.3 CFU/ml) and sands (1.7 CFU/g). Differences were observed between urban and non-urban coastal beaches with regard to isolation of dermatophytes only from one urban beach. The present study reports a great diversity of fungi in sand and water of bathing beaches confirming that the Mediterranean region has a greater variety of fungal species.

P352 Molds and yeasts on the beach: environmental factors influencing distribution of fungi along european shores

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PM

 

Objectives

The present study employed data collected during the Mycosands survey to investigate the environmental factors influencing yeasts and molds distribution along European shores by applying a species distribution modeling approach.

Methods

Occurrence data were compared to climatic datasets (temperature, precipitation, and solar radiation), soil datasets (chemical and physical properties), and water datasets (temperature, salinity, and chlorophyll concentration) downloaded from web databases. All dataset layers were edited and formatted by QGIS software and analyses were performed by MaxEnt software.

Results

The distribution maps inferred comparing occurrence data on shores for Aspergillus spp., Aspergillus fumigatus, A. flavus, A. niger, Fusarium spp., dematiaceous fungi, and considering all molds, to climatic datasets showed the highest probability of presence along Eastern and South-Central Mediterranean coasts, whereas comparison of water occurrence data to water features identified a high suitability along Eastern Mediterranean coasts, Gulf of Lion, Southern coasts of Spain, and Southern and Central Atlantic coast of Portugal, Southern Atlantic coast of France, Netherlands coasts, the mouth of Danube, coasts of the Ireland sea, and Kuri Lagoon in Lithuania. The main variables contributing to the models were minimum temperatures in winter, water temperature during spring, and chlorophyll concentration. The comparison with soil datasets showed a high tolerance of soils with a high concentration of CaCO3 and basic pH. Nitrogen concentration was tolerated at values below 1 g/kg and phosphorus concentration at values <20 mg/kg and >40 mg/kg. In addition, the model identified a high tolerance to soils rich in nickel.

The same analyses were performed for the following groups of occurrence data: Candida spp., Rhodotorula spp., and all yeasts. Results showed the highest probability of presence on shores located along the coasts of Eastern Mediterranean Sea, Southern-Central Mediterranean Sea, Northern Adriatic Sea coasts, Kuri Lagoon, and Northern European coasts from France to Denmark. In waters, high suitability areas were located along the coasts of Northern Black Sea, Northern Adriatic Sea, coasts of Ireland Sea, Western Atlantic coast of France, and the Northern European coasts from France to western Denmark. The most relevant variables contributing to the model were minimum temperatures during winter and water chlorophyll concentration. The comparison with soil features showed similar results to those obtained for molds, except a high tolerance for soils rich in cadmium.

Conclusions

All together our results suggest a different probability of distribution of yeasts and molds along European shores. Yeasts seem to tolerate low temperatures better during winter than molds and this reflects a higher suitability for the Northern European coasts. This difference is more evident considering suitability in waters. Both distributions of molds and yeasts are influenced by basic soil pH, probably because acidic soils are more favorable to bacterial growth. Soils with high nitrogen concentrations are not suitable for fungal growth, which, in contrast, are optimal for plant growth, favored by this environment. Finally, molds show affinity with soil rich in nickel and yeasts with soils rich in cadmium resulting in a distribution mainly at the mouths of European rivers or lagoons, where these metals accumulate in river sediments.

P039 Cross-resistance to clinical and agricultural azoles among Aspergillus fumigatus strains isolated from humans and environment in Italy

 

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PM

Objectives

In Italy, a prevalence of 16.9% of resistance to clinical azoles was observed among Aspergillus fumigatus isolates from an agricultural environment. This spread of azole-resistance is attributed to the widespread use of 14a-demethylase inhibitors (DMIs).

The aims of the present study were to investigate: the DMIs resistance in Italian A. fumigatus strains of clinical and environmental origin, both susceptible and resistant to clinical azoles; the molecular mechanism of resistance in strains susceptible to clinical azoles but resistant to at least one of the tested DMIs; the in vitro DMI resistance induced by prolonged exposure to DMIs in susceptible clinical and environmental strains, and the molecular mechanism of resistance.

Methods

A total of 54 A. fumigatus strains were selected: 23 susceptible to clinical azoles (CAS) and 31 resistant (CAR) with and without mutations in the CYP51A gene (TR34/L98H, F219I, G54R, G54E, D269Y, M220I, or F46Y/M172V/N248T/D255E/E427K). Antifungal susceptibility testing was performed for 8 DMIs (tebuconazole, epoxiconazole, difenoconazole, propiconazole, tetraconazole, flusilazole, fenbuconazole, and prochloraz) using broth microdilution method according to EUCAST and CLSI methods. Mutations in CYP51A, CYP51B, and HMG1 genes were investigated in CAS with DMI high MIC values. In vitro induction of resistance was performed using the 8 DMIs on 11 (6 clinical and 5 environmental) A. fumigatus strains susceptible both to clinical azoles and DMIs. A suspension of 106 conidia was inoculated on glucose-yeast extract-peptone agar plates containing different DMIs at different concentrations and incubated at 37°C for 72 h for six repeated passages.

Results

Comparable results were obtained using EUCAST and CLSI methods.

Resistance (MIC ≥16) to tetraconazole and fenbuconazole was observed in 100% of isolates, both CAR and CAS. On the contrary, a statistically significant difference in tebuconazole, epoxiconazole, difenoconazole, propiconazole, and flusilazole MICs between CAR strains and CAS strains was observed with higher geometric means (GM) in CAR (range 4.9-9.3 mg/L) than in CAS (1.5-2.7 mg/L) strains. Prochloraz showed the lowest GMs: 0.6 and 0.25 mg/L in CAR and CAS strains, respectively.

A significant difference of the GMs for all the DMIs tested, except prochloraz, was observed between the isolates harboring a TR34/L98H or a M220I mutation (GM range 10.4-16 mg/L) and those with other CYP51A mutations (GM range 1-4.6 mg/L).

In the CAS showing high DMI MICs, the absence of CYP51A mutations was confirmed, while a synonymous mutation P394P, was identified in CYP51B. No mutations in HMG1 gene were found.

In the induction tests, the prolonged exposure to DMIs showed an induced phenotypic resistance of 100% (11/11 isolates) for epoxiconazole, of 72.7% (8/11) for propiconazole, of 54% (6/11) for tebuconazole and difenoconazole, and of 9.1% (1/11) for prochloraz.

Molecular analysis to understand if the phenotypic resistance corresponds to induced mutations in CYP51A, CYP51B, and HMG1 genes is in progress.

Conclusions

Preliminary results confirm cross-resistance between clinical azoles and DMIs, with MIC differences between CAR and CAS and between strains with different mutations in the CYP51A gene. Furthermore, the ability of DMIs to induce resistance in vitro was highlighted.

Exploring Mitogenomes Diversity of Fusarium musae from Banana Fruits and Human Patients

Fusarium musae has recently been described as a cross-kingdom pathogen causing post-harvest disease in bananas and systemic and superficial infection in humans. The taxonomic identity of fungal cross-kingdom pathogens is essential for confirming the identification of the species on distant infected hosts. Understanding the level of variability within the species is essential to decipher the population homogeneity infecting human and plant hosts. In order to verify that F. musae strains isolated from fruits and patients are part of a common population and to estimate their overall diversity, we assembled, annotated and explored the diversity of the mitogenomes of 18 F. musae strains obtained from banana fruits and human patients. The mitogenomes showed a high level of similarity among strains with different hosts’ origins, with sizes ranging from 56,493 to 59,256 bp. All contained 27 tRNA genes and 14 protein-coding genes, rps3 protein, and small and large ribosomal subunits (rns and rnl). Variations in the number of endonucleases were detected. A comparison of mitochondrial endonucleases distribution with a diverse set of Fusarium mitogenomes allowed us to specifically discriminate F. musae from its sister species F. verticillioides and the other Fusarium species. Despite the diversity in F. musae mitochondria, strains from bananas and strains from human patients group together, indirectly confirming F. musae as a cross-kingdom pathogen.

In Vitro Antifungal Activity of Ibrexafungerp (SCY-078) Against Contemporary Blood Isolates From Medically Relevant Species of Candida: A European Study

Background

Ibrexafungerp (SCY-078) is the newest oral and intravenous antifungal drug with broad activity, currently undergoing clinical trials for invasive candidiasis.

Objective

The aim of this study was to assess the in vitro activity of ibrexafungerp and comparators against a collection of 434 European blood isolates of Candida.

Methods

Ibrexafungerp, caspofungin, fluconazole, and micafungin minimum inhibitory concentrations (MICs) were collected from 12 European laboratories for 434 blood isolates, including 163 Candida albicans, 108 Candida parapsilosis, 60 Candida glabrata, 40 Candida tropicalis, 29 Candida krusei, 20 Candida orthopsilosis, 6 Candida guilliermondii, 2 Candida famata, 2 Candida lusitaniae, and 1 isolate each of Candida bracarensis, Candida catenulata, Candida dubliniensis, and Candida kefyr. MICs were determined by the EUCAST broth microdilution method, and isolates were classified according to recommended clinical breakpoints and epidemiological cutoffs. Additionally, 22 Candida auris from different clinical specimens were evaluated.

Results

Ibrexafungerp MICs ranged from 0.016 to ≥8 mg/L. The lowest ibrexafungerp MICs were observed for C. albicans (geometric MIC 0.062 mg/L, MIC range 0.016–0.5 mg/L) and the highest ibrexafungerp MICs were observed for C. tropicalis (geometric MIC 0.517 mg/L, MIC range 0.06–≥8 mg/L). Modal MICs/MIC₅₀s (mg/L) against Candida spp. were 0.125/0.06 for C. albicans, 0.5/0.5 for C. parapsilosis, 0.25/0.25 for C. glabrata, 0.5/0.5 for C. tropicalis, 1/1 for C. krusei, 4/2 for C. orthopsilosis, and 0.5/0.5 for C. auris. Ibrexafungerp showed activity against fluconazole- and echinocandin-resistant isolates. If adopting wild-type upper limits, a non-wild-type phenotype for ibrexafungerp was only observed for 16/434 (3.7%) isolates: 11 (4.6%) C. parapsilosis, 4 (5%) C. glabrata, and 1 (2.5%) C. tropicalis.

Conclusion

Ibrexafungerp showed a potent in vitro activity against Candida.

Catheter-related blood stream infection caused by Millerozyma farinosa in an immunocompetent patient: a case report and a brief review of the literature

Millerozyma farinose is a halotolerant yeast that has recently been described as an emerging human pathogen, especially in immunocompromised patients. Both the diagnostic process and treatment options are still unclear. Here, we report a case of an immunocompetent oncological patient who developed a catheter-related bloodstream infection (CRBSI) with a concomitant respiratory tract infection caused by M. farinosa. In this report, we discuss how prompt microbiological identification and attentive evaluation of the patient's clinical status can play a significant role in the appropriate management of infections caused by uncommon fungi. MALDI-TOF technology has also substantially improved the timely diagnosis of rare fungi. Furthermore, our diagnosis was subsequently confirmed by 5.8S rRNA sequencing. In our patient, the rapid diagnosis of fungaemia was crucial, together with catheter removal and the initiation of antifungal treatment, for the patient's clinical improvement.

ICU ENVIRONMENTAL SURFACES ARE A RESERVOIR OF FUNGI: SPECIES DISTRIBUTION IN NORTHERN ITALY

BACKGROUND

Preventing and reducing nosocomial infections is a public health goal. Concern about healthcare-associated fungal infections has increased in recent years, due to the emergence and spread of new pathogens, increasing antifungal resistance and outbreaks in hospital settings.

AIM

This study investigated the presence of medically-relevant fungal species on environmental surfaces in 12 intensive care units of 8 hospitals in Milan, Italy.

METHODS

Environmental samplings, using contact plates on surfaces near bed stations and medical workstations, were conducted between November 2019 and January 2020. Fungi isolated were identified and some were tested in vitro for antifungal susceptibility.

FINDINGS

A total of 401 environmental samples were collected from 61 bed stations and 17 medical workstations. Positive samples were found in all hospitals except one, with positivity rates ranging from 4% to 24.2%. Filamentous fungi were found mainly on infusion pumps (23.2%) and patient tables (21.2%), whereas yeasts were mainly on computers (25%) and floors (10.9%). Fungi were isolated from 12% of total samples. Filamentous fungi, mainly Aspergillus fumigatus, grew in 70.8% of positive samples, and yeasts in 27.1%, mainly Candida parapsilosis (42.8%) and C. glabrata (28.6%). Fungi were detected both near patients' beds and on surfaces at workstations, indicating potential for environment-to-patient, patient-to-patient and healthcare workers-to-patient transmission CONCLUSIONS: This study highlights that surveillance in hospital settings through environmental sampling may be an important component of fungal infection prevention.

Candidemia: Evolution of Drug Resistance and Novel Therapeutic Approaches

Candidemia and invasive candidiasis are the most common healthcare-associated invasive fungal infections, with a crude mortality rate of 25–50%. Candida albicans remains the most frequent etiology, followed by C. glabrata, C. parapsilosis and C. tropicalis. With the exception of a limited number of species (ie: C. krusei, C. glabrata and rare Candida species), resistance to fluconazole and other triazoles are quite uncommon. However, recently fluconazole-resistant C. parapsilosis, echinocandin-resistant C. glabrata and the multidrug resistant C. auris have emerged. Resistance to amphotericin B is even more rare due to the reduced fitness of resistant isolates. The mechanisms of antifungal resistance in Candida (altered drug-target interactions, reduced cellular drug concentrations, and physical barriers associated with biofilms) are analyzed. The choice of the antifungal therapy for candidemia must take into account several factors such as type of patient, presence of devices, severity of illness, recent exposure to antifungals, local epidemiology, organs involvement, and Candida species. The first-line therapy in non-neutropenic critical patient is an echinocandin switching to fluconazole in clinically stable patients with negative blood cultures and azole susceptible isolate. Similarly, an echinocandin is the drug of choice also in neutropenic patients. The treatment duration is 14 days after the first negative blood culture or longer in cases of organ involvement. An early removal of vascular catheter improves the outcome. The promising results of new antifungal molecules, such as the terpenoid derivative ibrexafungerp, the novel echinocandin with an enhanced half-life rezafungin, oteseconazole and fosmanogepix, representative of new classes of antifungals, are discussed.

Fusarium musae from Diseased Bananas and Human Patients: Susceptibility to Fungicides Used in Clinical and Agricultural Settings

Fusarium musae belongs to the Fusarium fujikuroi species complex. It causes crown rot disease in banana but also keratitis and skin infections as well as systemic infections in immunocompromised patients. Antifungal treatments in clinical and agricultural settings rely mostly on molecules belonging to the azole class. Given the potential risk of pathogen spread from food to clinical settings, the goal of the work was to define the level of susceptibility to different azoles of a worldwide population of F. musae. Eight fungicides used in agriculture and five antifungals used in clinical settings (4 azoles and amphotericin B) were tested using the CLSI (Clinical and Laboratory Standards Institute) protocol methodology on 19 F. musae strains collected from both infected patients and bananas. The level of susceptibility to the different active molecules was not dependent on the source of isolation with the exception of fenbuconazole and difenoconazole which had a higher efficiency on banana-isolated strains. Minimal inhibitory concentrations (MICs) of the different molecules ranged from 0.12–0.25 mg/L for prochloraz to more than 16 mg/L for tetraconazole and fenbuconazole. Compared to the F. verticillioides, F. musae MICs were higher suggesting the importance of monitoring the potential future spread of this species also in clinical settings.

Mycosands: Fungal diversity and abundance in beach sand and recreational waters - Relevance to human health

The goal of most studies published on sand contaminants is to gather and discuss knowledge to avoid faecal contamination of water by run-offs and tide-retractions. Other life forms in the sand, however, are seldom studied but always pointed out as relevant. The Mycosands initiative was created to generate data on fungi in beach sands and waters, of both coastal and freshwater inland bathing sites. A team of medical mycologists and water quality specialists explored the sand culturable mycobiota of 91 bathing sites, and water of 67 of these, spanning from the Atlantic to the Eastern Mediterranean coasts, including the Italian lakes and the Adriatic, Baltic, and Black Seas. Sydney (Australia) was also included in the study. Thirteen countries took part in the initiative. The present study considered several fungal parameters (all fungi, several species of the genus Aspergillus and Candida and the genera themselves, plus other yeasts, allergenic fungi, dematiaceous fungi and dermatophytes). The study considered four variables that the team expected would influence the results of the analytical parameters, such as coast or inland location, urban and non-urban sites, period of the year, geographical proximity and type of sediment. The genera most frequently found were Aspergillus spp., Candida spp., Fusarium spp. and Cryptococcus spp. both in sand and in water. A site-blind median was found to be 89 Colony-Forming Units (CFU) of fungi per gram of sand in coastal and inland freshwaters, with variability between 0 and 6400 CFU/g. For freshwater sites, that number was 201.7 CFU/g (0, 6400 CFU/g (p = 0.01)) and for coastal sites was 76.7 CFU/g (0, 3497.5 CFU/g). For coastal waters and all waters, the median was 0 CFU/ml (0, 1592 CFU/ml) and for freshwaters 6.7 (0, 310.0) CFU/ml (p < 0.001). The results advocate that beaches should be monitored for fungi for safer use and better management.

Phylogenomic Analysis of a 55.1-kb 19-Gene Dataset Resolves a Monophyletic Fusarium that Includes the Fusarium solani Species Complex

Scientific communication is facilitated by a data-driven, scientifically sound taxonomy that considers the end-user's needs and established successful practice. In 2013, the Fusarium community voiced near unanimous support for a concept of Fusarium that represented a clade comprising all agriculturally and clinically important Fusarium species, including the F. solani species complex (FSSC). Subsequently, this concept was challenged in 2015 by one research group who proposed dividing the genus Fusarium into seven genera, including the FSSC described as members of the genus Neocosmospora, with subsequent justification in 2018 based on claims that the 2013 concept of Fusarium is polyphyletic. Here, we test this claim and provide a phylogeny based on exonic nucleotide sequences of 19 orthologous protein-coding genes that strongly support the monophyly of Fusarium including the FSSC. We reassert the practical and scientific argument in support of a genus Fusarium that includes the FSSC and several other basal lineages, consistent with the longstanding use of this name among plant pathologists, medical mycologists, quarantine officials, regulatory agencies, students, and researchers with a stake in its taxonomy. In recognition of this monophyly, 40 species described as genus Neocosmospora were recombined in genus Fusarium, and nine others were renamed Fusarium. Here the global Fusarium community voices strong support for the inclusion of the FSSC in Fusarium, as it remains the best scientific, nomenclatural, and practical taxonomic option available.

Azole resistance in Aspergillus isolates by different types of patients and correlation with environment - An Italian prospective multicentre study (ARiA study)

BACKGROUND

A wide range of frequency of azole-resistance in A fumigatus in different patient populations worldwide was observed threatening to reduce therapeutic options.

OBJECTIVES

Estimate the prevalence of azole-resistance, investigate the molecular mechanisms of resistance, compare the genotypes of resistant clinical isolates with those from the surrounding environment.

METHODS

Aspergillus isolates were collected by seven Italian hospital microbiology laboratories. Strains were isolated from different clinical samples from unselected patients. The azole-resistance was evaluated using screening test and microdilution EUCAST method. The molecular mechanism of resistance was performed sequencing the cyp51A gene. Resistant isolates were genotyped by microsatellite analysis and their profiles compared with those of azole-resistant isolates from previous Italian studies.

RESULTS

425 Aspergillus isolates from 367 patients were analysed. The azole-resistance rates were 4.9% and 6.6% considering all Aspergillus spp. isolates and the A fumigatus sensu stricto, respectively. All resistant isolates except one were from a single hospital. Two rare azole-resistant species were identified: A thermomutatus and A lentulus. The predominant resistance mechanism was TR₃₄ /L98H. No correlation between the clinical resistant strains and environmental isolates from patients' home/work/ward was observed. The analysis of the molecular correlation between the resistant clinical strains collected in the present study and those of environmental and clinical origin collected in previous Italian studies reveals a progressive diversification of azole-resistant genotypes starting from a founder azole-resistant genotype.

CONCLUSIONS

This study confirms the trend of azole-resistance rate in Italy, showing a geographical difference. Data reinforce the importance of surveillance programmes to monitor the local epidemiological situation.

Tobacco and e-cigarette smoking habits among Italian healthcare students

BACKGROUND

Healthcare professionals might play a significant role in tobacco control. The aims of this study were to investigate tobacco cigarette and electronic cigarette (e-cigarette) consumption among university students enrolled in courses of the healthcare area, and to understand whether training in healthcare could induce to smoking cessation.

STUDY DESIGN

Cross-sectional survey using a self-administered, structured questionnaire.

METHODS

Tobacco smoking habits of 560 students of four different medical area courses at the University of Milan, enrolled both in the first and in the last course year during the 2017-2018 academic year, were collected.

RESULTS

The prevalence of smokers was 34.8%, almost the same for males and females, and higher in Italian students compared to foreigners. Smoking prevalence was higher among employed (46.9%) than unemployed (35.1%) students, without differences between healthcare and non-healthcare workers. The influence of family, and particularly friends, is confirmed to be relevant. About 25% of respondents tried e-cigarettes, mainly smokers (44.6%) and former smokers (38.6%) with the goal of quitting smoking. More than 44% were dual users of both tobacco cigarettes and e-cigarettes. Comparing smoking habits between first-year and final-year students, only students of healthcare assistance course showed a significant drop in smoking during the university studies.

CONCLUSIONS

The implementation of specific educational curricula on smoking dangers and on smoking cessation techniques might have the double effect of supporting students in quitting smoking and of properly preparing them for their future task of helping people to quit smoking.

Prospective multicentre study on azole resistance in Aspergillus isolates from surveillance cultures in haematological patients in Italy

OBJECTIVES

This study was conducted to assess the prevalence of azole resistance in Aspergillus isolates from patients with haematological malignancies or who were undergoing haematopoietic stem cell transplantation and to identify the molecular mechanism of resistance.

METHODS

In this 28-month prospective study involving 18 Italian centres, Aspergillus isolates from surveillance cultures were collected and screened for azole resistance, and mutations in the cyp51A gene were identified. Resistant isolates were genotyped by microsatellite analysis, and the allelic profiles were compared with those of resistant environmental and clinical isolates from the same geographical area that had been previously genotyped.

RESULTS

There were 292 Aspergillus isolates collected from 228 patients. The isolates belonged mainly to the section Fumigati (45.9%), Nigri (20.9%), Flavi (16.8%) and Terrei (4.8%). Three isolates showed itraconazole resistance: Aspergillus fumigatus sensu stricto, Aspergillus lentulus (section Fumigati) and Aspergillus awamori (section Nigri). The itraconazole resistance rates were 1% and 1.48% considering all Aspergillus spp. isolates and the Aspergillus section Fumigati, respectively. The prevalence of azole resistance among all the patients was 1.3%. Among patients harbouring A. fumigatus sensu stricto isolates, the resistance rate was 0.79%. The A. fumigatus isolate, with the TR₃₄/L98H mutation, was genotypically distant from the environmental and clinical strains previously genotyped.

CONCLUSIONS

In this study, the Aspergillus azole resistance rate was 1% (3/292). In addition to A. fumigatus sensu stricto, A. lentulus and A. awamori azole-resistant isolates were identified. Therefore, it is important have a correct identification at the species level to address a rapid therapy better, quickly understand the shift towards cryptic species and have an updated knowledge of the local epidemiology.

Yeast-like filamentous fungi: Molecular identification and in vitro susceptibility study

Yeast-like filamentous fungi, collected in Italy from 1985 to 2018, were submitted to molecular identification and antifungal susceptibility testings. Clinical isolates were identified as Magnusiomyces capitatus (28), M. clavatus (18), and Geotrichum candidum (2). M. clavatus was prevalent among blood isolates (18/24), M. capitatus among isolates from other biological materials. The intrinsic echinocandin resistance was confirmed. Both species had low minimum inhibitory concentrations (MICs) of itraconazole, posaconazole, and voriconazole, while M. clavatus had lower MIC of flucytosine and higher MIC of isavuconazole than M. capitatus. The intrinsic resistance of these species to echinocandins could be the reason of the recent increase of M. clavatus bloodstream infections.

Cryptococcus neoformans and Cryptococcus gattii Species Complex Isolates on the Slopes of Mount Etna, SICILY, Italy

This study investigated the presence of Cryptococcus neoformans and Cryptococcus gattii species complex isolates on olive trees growing in the Eastern part of Sicily (Italy) characterized by the presence of the volcano Etna and the ability of these fungal pathogens to sexually reproduce on medium containing volcanic soil. Samples from 124 olive trees were collected from 14 different sites around Mount Etna. Eighteen trees (14.5%) resulted colonized by C. neoformans VNI-αA isolates, one (0.8%) by VNIV-αD isolates, and two (1.6%) by C. gattii VGI-αB isolates. The ability of environmental and reference strains belonging to VNI, VNIV, and VGI molecular types to sexually reproduce on a medium containing volcanic soil was also tested. VNI and VNIV strains were able to produce filaments and basiodiospores more vigorously than on the control medium, whereas VGI strains were not fertile. In conclusion, the present study identified which C. neoformans and C. gattii species complex genotypes are circulating in Eastern Sicily and confirmed the ecological role of olive trees as environmental reservoir of these pathogens. It also showed that Cryptococcus is able to colonize and sexually reproduce in inhospitable environments such as the slopes of a volcano.

Evolution of fungemia in an Italian region

BACKGROUND

Fungemia represents a public health concern. Knowing aetiology and activity of the antifungals is critical for the management of bloodstream infections. Therefore, surveillance on local/international levels is desirable for a prompt administration of appropriate therapy.

METHODS

Data on fungi responsible for fungemia and antifungal susceptibility profiles were collected from a laboratory-based surveillance over 2016-2017 in 12 hospitals located in Lombardia, Italy. The trend of this infection in twenty years was analysed.

RESULTS

A total of 1024 episodes were evaluated. Rate of candiaemia progressively increased up to 1.46/1000 admissions. C.albicans was the most common species (52%), followed by C. parapsilosis (15%) and C glabrata (13%). As in the previous surveys the antifungal resistance is rare (echinocandins<2%, fluconazole 6%, amphotericin B 0.6%). Fungi other than Candida were responsible for 18 episodes: Cryptococcus neoformans (5 cases), Fusarium spp. (4), Magnusiomyces clavatus (3), Saccharomyces cerevisiae (3), Rhodotorula spp. (2), Exophiala dermatitidis (1). All fungi, except S.cerevisiae, were intrinsically resistant to echinocandins. Some isolates showed also elevated azole MIC.

CONCLUSIONS

No particular changes in terms of species distribution and antifungal susceptibility patterns was noted. However, surveillance programs are needed to monitor trends in antifungal resistance, steer stewardship activities, orient empirical treatment.

Epidemiological trends of cryptococcosis in Italy: Molecular typing and susceptibility pattern of Cryptococcus neoformans isolates collected during a 20-year period

In the present study clinical data and isolates from cases of cryptococcosis recorded during clinical surveys carried out in Italy from 1997 to 2016, were investigated. Molecular typing and antifungal susceptibility testing were performed in order to delineate the epidemiological trend of cryptococcosis in Italy and to define wild-type population for four different antifungal compounds. During the studied period, a total of 302 cases collected from 32 centers of 11 Italian regions were recorded. Analysis of clinical data showed a significant increase of frequency (from 7% to 38%) of cryptococcosis in human immunodeficiency virus (HIV)-negative patients primarily with hematologic malignancies and solid organ transplantations. The prevalence of the molecular types has significantly changed during the study period, showing an increase of VNIII isolates from 11% to 41% in HIV-negative patients, and a decrease of VNIV isolates from 36% to 16%. Antifungal susceptibility testing allowed us to calculate the epidemiological cut-off for flucytosine (1 mg/l), fluconazole (8 mg/l), itraconazole (0.5 mg/l), and voriconazole (0.25 mg/l). Most of the isolates were wild-type strains. Comparison of the MIC distributions according to molecular types showed that VNIV isolates had lower MICs for fluconazole and itraconazole than the VNI and VIII isolates. The current study emphasizes that the epidemiology of cryptococcosis in Italy has significantly changed over the last decades.

Presence of L701 M mutation in the FKS1 gene of echinocandin-susceptible Candida krusei isolates

Resistance of Candida krusei isolates to echinocandins, the recommended drugs to treat candidemia, has been associated with mutations in hot spot (HS) regions of the FKS1 gene or L701 M mutation in a region between HS1 and HS3 of FKS1. However, the role of L701 M mutation alone in causing reduced echinocandins susceptibility is still unclear. We analyzed a region between HS1 and HS3 of FKS1 of 25 C. krusei isolates from clinical samples. Susceptibility to echinocandins was determined by a commercial broth microdilution assay and by the microdilution method according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST). The L701 M mutation was detected in 22/25 (88%) C. krusei isolates with low MIC values in the absence of other HS mutations. The presence of isolated L701 M mutation in C. krusei clinical isolates susceptible to echinocandins suggests that this mutation may be just associated to polymorphism in the C. krusei population.

Multi-Locus Next-Generation Sequence Typing of DNA Extracted From Pooled Colonies Detects Multiple Unrelated Candida albicans Strains in a Significant Proportion of Patient Samples

The yeast Candida albicans is an important opportunistic human pathogen. For C. albicans strain typing or drug susceptibility testing, a single colony recovered from a patient sample is normally used. This is insufficient when multiple strains are present at the site sampled. How often this is the case is unclear. Previous studies, confined to oral, vaginal and vulvar samples, have yielded conflicting results and have assessed too small a number of colonies per sample to reliably detect the presence of multiple strains. We developed a next-generation sequencing (NGS) modification of the highly discriminatory C. albicans MLST (multilocus sequence typing) method, 100+1 NGS-MLST, for detection and typing of multiple strains in clinical samples. In 100+1 NGS-MLST, DNA is extracted from a pool of colonies from a patient sample and also from one of the colonies. MLST amplicons from both DNA preparations are analyzed by high-throughput sequencing. Using base call frequencies, our bespoke DALMATIONS software determines the MLST type of the single colony. If base call frequency differences between pool and single colony indicate the presence of an additional strain, the differences are used to computationally infer the second MLST type without the need for MLST of additional individual colonies. In mixes of previously typed pairs of strains, 100+1 NGS-MLST reliably detected a second strain. Inferred MLST types of second strains were always more similar to their real MLST types than to those of any of 59 other isolates (22 of 31 inferred types were identical to the real type). Using 100+1 NGS-MLST we found that 7/60 human samples, including three superficial candidiasis samples, contained two unrelated strains. In addition, at least one sample contained two highly similar variants of the same strain. The probability of samples containing unrelated strains appears to differ considerably between body sites. Our findings indicate the need for wider surveys to determine if, for some types of samples, routine testing for the presence of multiple strains is warranted. 100+1 NGS-MLST is effective for this purpose.

Evaluation of Real Time PCR Aspergillus spp. in bronchoalveolar lavage samples

The present study investigated the improvement in the diagnosis of invasive pulmonary aspergillosis (IPA) adding a molecular test on bronchoalveolar lavage (BAL) to the routine diagnostic approach including microscopy, culture and galactomannan (GM) immunoassay. A total of 133 BAL samples were retrospectively tested for the Aspergillus DNA: 112 samples were from immunocompromised patients at risk of invasive fungal infection and 21 were from patients not at risk and without clinical evidence of IPA. The latter samples were used to identify the cut-off of positivity for the molecular test. Applying the cut-off quantity of 50 copies/reaction, the PCR test had 90% sensitivity and 97% specificity and resulted the most sensitive, specific and accurate among those evaluated. The statistical analysis showed that the probability that a patient is not affected by IPA is 99% when the three tests (PCR, GM and culture) are concordantly negative.

Antibiotic resistance: Italian awareness survey 2016

Antimicrobial resistance has become a public health priority worldwide. The WHO conducted a survey concerning the personal use of antibiotics, knowledge of appropriate use and awareness of the issue of resistance. A similar survey was conducted in Italy involving 666 young university students and 131 seniors attending courses of the University of the third age. Antibiotics seem to be taken with moderate frequency and appropriately: 30% of respondents took them in the past six months and 94% took these drugs only prescribed by a doctor, in the correct dose and for the proper duration. Notable confusion concerning the conditions treatable with antibiotics was detected (only 30% indicated gonorrhea, and 30-40% believed that antibiotics should be employed for fever, cold, and flu), while 94% of participants seemed aware of the problem of antibiotic resistance. Most of the respondents identified the behaviors that can reduce the phenomenon of resistance (regular handwashing and use of antibiotics only when prescribed and needed). The results of our survey, that involved people of high level of instruction and living in urban areas of northern regions, cannot be extended to all the Italian population. However, they provide valid elements to promote initiatives aimed to a more aware use of antibiotics.

Azole Resistance in Aspergillus fumigatus Clinical Isolates from an Italian Culture Collection

The aims of the study were to investigate the prevalence of azole resistance among Aspergillus fumigatus clinical isolates. A total of 533 clinical isolates that had been collected between 1995 and 2006, from 441 patients, were screened. No resistance was detected in isolates collected between 1995 and 1997. Starting in 1998, the resistance rate was 6.9%; a total of 24 patients (6.25%) harbored a resistant isolate. The TR34/L98H substitution was found in 21 of 30 tested isolates.

Trichophyton concentricum in skin lesions in children from the Salomon Islands

AIM

Aim of the paper was to report cases of Tinea imbricata, a mycosis caused by the anthropophilic dermatophyte Trichophyton concentricum, observed in 2012 in Guadalcanal, the largest of the Salomon islands.

METHODS

During 2012, several cases of Tinea imbricata, called bakwa by local people, were observed in the Little Samaritan Hospital in Guadalcanal. Skin scrapings collected from three young patients were examined in Italy to confirm the clinical diagnosis. The fungus grown on culture was morphologically identified and submitted to sequencing of the ITS1-ITS2 region.

RESULTS

The diagnosis obtained by visual inspection of the skin lesions, characterised by concentric and lamellar plaques of scale often involving large part of the body, was confirmed mycological investigations. A prevalence of 15% of Tinea imbricata in this population was hypothesized. The fungus grown on culture was morphologically identified as Trichophyton concentricum and identification was confirmed sequencing the ITS1-ITS2 region. Patients were treated with potassium permanganate solution soaked gauze followed by colloidal sulfur and salicylic acid cream application. However, the efficacy of the antifungal treatment was difficult to evaluate due to the poor compliance of the patients and the remoteness of the villages.

CONCLUSION

Italian clinicians and mycologists should be aware of this fungal infection because the increased number of international travels and of migration rise the spread of infections previously restricted to limited geographical areas.

Acquired echinocandin resistance in a Candida krusei blood isolate confirmed by mutations in the fks1 gene

We describe a case of bloodstream infection caused by a Candida krusei strain that developed echinocandin resistance during caspofungin therapy. Three mutations were found in the HS1 region of the fks1 gene, two of them have never been reported either in C. krusei nor in C. albicans.

Azole-resistant Aspergillus fumigatus in the environment of northern Italy, May 2011 to June 2012

In recent years acquired azole resistance in Aspergillus fumigatus has been increasingly reported and a dominant mechanism of resistance (TR34/L98H) was found in clinical and environmental isolates. The aim of the present study was to investigate the prevalence of azole resistance in environmental A. fumigatus isolates collected in northern Italy. A. fumigatus grew from 29 of 47 soil samples analysed. Azole-resistant isolates were detected in 13% (6/47) of the soil samples and in 21% (6/29) of the soil samples containing A. fumigatus. High minimal inhibitory concentrations (MIC) of itraconazole (≥16 mg/L) and posaconazole (≥0.5 mg/L) were displayed by nine isolates from six different soil samples, namely apple orchard (1 sample), rose pot compost (2 samples), and cucurbit yields (3 samples). Seven isolates had a MIC=2 mg/L of voriconazole. Seven of nine itraconazole and posaconazole resistant isolates harboured the same TR34/L98H mutation of cyp51A. These findings, together with the occurrence of resistant clinical isolates, suggest that azole resistance should be considered in primary patient care.

Antifungal susceptibility profiles of Candida isolates from a prospective survey of invasive fungal infections in Italian intensive care units

The antifungal susceptibility pattern of 302 Candida isolates collected during an Italian survey on invasive fungal infections in an intensive care setting was investigated. The results were correlated with some epidemiological data and compared with the antifungal profiles obtained in a previous survey. No resistance to echinocandins was detected. The overall resistance levels to fluconazole, posaconazole and voriconazole were 12.6, 6.0 and 7.1 %, respectively. Candida tropicalis and Candida parapsilosis accounted for more than half of all the fluconazole resistant isolates. Reduced susceptibility to fluconazole is not uncommon among isolates (12.3 %) and appears to be increasing, particularly among C. parapsilosis isolates, which showed an increase in resistant isolates from 2 % in the 1990s to 25.8 % in the present study. Routine antifungal susceptibility testing of this species is therefore recommended.

In vitro activity of conventional antifungal drugs and natural essences against the yeast-like alga Prototheca

BACKGROUND

Two outbreaks of mastitis due to the yeast-like alga Prototheca zopfii recently occurred in dairy herds in Lombardia (Italy) involving 180 and 150 lactating cows, respectively.

OBJECTIVES

To determine the in vitro susceptibility of Prototheca isolates to conventional antifungal agents and to essential oils.

METHODS

Twenty P. zopfii isolated from milk during these outbreaks, six P. zopfii isolated from fresh water and two Prototheca sp. reference strains were submitted to antifungal susceptibility testing by broth microdilution assay following the CLSI guidelines for yeasts.

RESULTS

The tested isolates were shown to be resistant to fluconazole and caspofungin. A wide range of voriconazole MICs was observed. In contrast, amphotericin B, itraconazole and posaconazole appeared active with MICs < or = 1 mg/L. Bergamot and tea tree oils seemed to exert an interesting activity against this yeast-like alga.

CONCLUSIONS

Difficulties in treating animals with conventional drugs and the potent in vitro activity of essential oils demonstrated here raise the interest in further investigations on the therapeutic use of these non-conventional natural products.

Four-year persistence of a single Candida albicans genotype causing bloodstream infections in a surgical ward proven by multilocus sequence typing

The present study represents the first application of multilocus sequence typing to retrospectively investigate a suspected outbreak of Candida albicans bloodstream infection cases that occurred in the same hospital ward between July 1987 and October 1991. Results demonstrated that eight bloodstream infections were caused by the same strain, endemic in the ward, over a 4-year period.

In vitro testing of fungicidal activity of biocides against Aspergillus fumigatus

The activity of biocides against Aspergillus fumigatus is unknown. In the European guidelines to evaluate the fungicidal activity of a biocide, the critical step concerning the preparation of conidial suspensions is cumbersome and time-consuming. The aims of this study were to evaluate a simplified procedure to prepare conidial suspensions to test a biocide in comparison with the recommended one and to investigate the in vitro activity of seven biocides by the suspension neutralization method against A. fumigatus clinical isolates. The proposed simplified procedure proved reproducible, gave the same results and was quicker than that described in the European guidelines. Benzalkonium chloride (0.25 %), glutaraldehyde (1.6 %), polyvinylpyrrolidone iodine (1 % available iodine) and polyester glycol iodine (0.18 % available iodine) showed biocidal activity in <or=5 min contact time, and chlorine (0.14 % available Cl) and chlorhexidine (0.06 %) after 15 min and 30-60 min, respectively. In contrast, chloramine-T (0.01 %) did not show biocidal activity. In addition, a simplified and reproducible procedure may be used for testing the fungicidal activity of new compounds or combined formulations. In conclusion, the biocides tested, which are commonly used in hospital settings, were shown to display biocidal activity against A. fumigatus and a simplified procedure may be adopted for testing the fungicidal activity of new compounds.

The European Confederation of Medical Mycology (ECMM) survey of candidaemia in Italy: in vitro susceptibility of 375 Candida albicans isolates and biofilm production

OBJECTIVES

To investigate the in vitro antifungal susceptibility pattern of 375 Candida albicans bloodstream isolates recovered during the European Confederation of Medical Mycology survey of candidaemia performed in Lombardia, Italy and to test the ability to form biofilm.

METHODS

In vitro susceptibility to flucytosine, fluconazole, itraconazole, posaconazole, voriconazole and caspofungin was performed by broth microdilution following the NCCLS guidelines. Biofilm production was measured using the XTT reduction assay in 59 isolates selected as representative of different patterns of susceptibility to flucytosine and azoles.

RESULTS

MICs (mg/L) at which 90% of the strains were inhibited were < or =0.25 for flucytosine, 0.25 for caspofungin, 4 for fluconazole and 0.06 for itraconazole, voriconazole and posaconazole. Flucytosine resistance was detected in five isolates and was associated with serotype B in 2/29 and serotype A in 3/346. Resistance to fluconazole was detected in 10 isolates; nine of these exhibited reduced susceptibility to the other azoles. Among the 10 patients with fluconazole-resistant C. albicans bloodstream infection, only one, an AIDS patient, had been previously treated with fluconazole. Biofilm production was observed in 23 isolates (39%) and was significantly associated with serotype B. No relationship was detected with the pattern of antifungal susceptibility.

CONCLUSIONS

Resistance is uncommon in C. albicans isolates recovered from blood cultures, while biofilm production is a relatively frequent event. Periodic surveillance is warranted to monitor the incidence of in vitro antifungal resistance as well as of biofilm production.

The European Confederation of Medical Mycology (ECMM) survey of candidaemia in Italy: antifungal susceptibility patterns of 261 non-albicans Candida isolates from blood

OBJECTIVES

To analyse the in vitro antifungal susceptibility of 261 non-albicans Candida bloodstream strains isolated during the European Confederation of Medical Mycology survey of candidaemia performed in Lombardia, Italy (September 1997-December 1999).

METHODS

In vitro susceptibility to flucytosine, fluconazole, itraconazole, posaconazole and voriconazole was determined using the broth microdilution method described in the NCCLS M27-A guidelines. Etest strips were used to assess susceptibility to amphotericin B. In vitro findings were correlated with the patient's underlying condition and previous antifungal treatment.

RESULTS

MICs (mg/L) at which 90% of the strains were inhibited were, respectively, 2 for flucytosine, 8 for fluconazole, 0.5 for itraconazole, 0.25 for voriconazole and 0.25 for posaconazole. Amphotericin B MIC endpoints were <0.50 mg/L in all the isolates tested. Flucytosine resistance was detected in 19 isolates (7%), mainly among Candida tropicalis strains (30%). Innate or secondary fluconazole resistance was detected in 13 strains (5%). Among the 13 patients with fluconazole-resistant Candida bloodstream infection, three were HIV positive, including one treated with fluconazole for oral candidosis; the four who were HIV negative had received the azole during the 2 weeks preceding the candidaemia. Cross-resistance among fluconazole and other azoles was a rare event.

CONCLUSIONS

Resistance is still uncommon in non-albicans Candida species recovered from blood cultures. However, in fungaemias caused by C. tropicalis, Candida glabrata and Candida krusei, there is a high prevalence of resistance to fluconazole and flucytosine. Fluconazole resistance should be suspected in patients treated previously with azoles, mainly those with advanced HIV infection.