Incidence of dsRNA mycoviruses in a collection of Aspergillus fumigatus isolates.

A collection of clinical and environmental isolates of the opportunistic human pathogen, Aspergillus fumigatus, were screened for the presence of mycoviruses and 6.6 % of 366 isolates contained dsRNA segments ranging in size from ~1.0 to 4.0 kbp. The dsRNAs were categorised into three different groups comprising bipartite dsRNAs, quadripartite dsRNAs, representative isolates of which have both been sequenced, and an uncharacterised mycovirus, whose genome apparently consists of four dsRNAs 1-2.5 kbp in size. Here, we describe dsRNA incidence in the A. fumigatus isolates examined, their provenance and also note that on occasion individual isolates were infected with two groups of different dsRNAs.

The effects of dsRNA mycoviruses on growth and murine virulence of Aspergillus fumigatus.

Some isolates of the opportunistic human pathogenic fungus Aspergillus fumigatus are known to be infected with mycoviruses. The dsRNA genomes of two of these mycoviruses, which include a chrysovirus and a partitivirus, have been completely sequenced and an RT-PCR assay for the viruses has been developed. Through curing virus-infected A. fumigatus isolates by cycloheximide treatment and transfecting virus-free isolates with purified virus, as checked by RT-PCR, isogenic virus-free and virus-infected lines of the fungus were generated whose phenotypes and growth have been directly compared. Mycovirus infection of A. fumigatus with either the chrysovirus or the partitivirus resulted in significant aberrant phenotypic alterations and attenuation of growth of the fungus but had no effect on susceptibility to common antifungals. Chrysovirus infection of A. fumigatus caused no significant alterations to murine pathogenicity.

Surveillance for Azole-Resistant Aspergillus fumigatus in a Centralized Diagnostic Mycology Service, London, United Kingdom, 1998-2017.

Background/Objectives: Aspergillus fumigatus is the leading cause of invasive aspergillosis. Treatment is hindered by the emergence of resistance to triazole antimycotic agents. Here, we present the prevalence of triazole resistance among clinical isolates at a major centralized medical mycology laboratory in London, United Kingdom, in the period 1998-2017. Methods: A large number (n = 1469) of clinical A. fumigatus isolates from unselected clinical specimens were identified and their susceptibility against three triazoles, amphotericin B and three echinocandin agents was carried out. All isolates were identified phenotypically and antifungal susceptibility testing was carried out by using a standard broth microdilution method. Results: Retrospective surveillance (1998-2011) shows 5/1151 (0.43%) isolates were resistant to at least one of the clinically used triazole antifungal agents. Prospective surveillance (2015-2017) shows 7/356 (2.2%) isolates were resistant to at least one triazole antifungals demonstrating an increase in incidence of triazole-resistant A. fumigatus in our laboratory. Among five isolates collected from 2015 to 2017 and available for molecular testing, three harbored TR34/L98H alteration in the cyp51A gene that are associated with the acquisition of resistance in the non-patient environment. Conclusion: These data show that historically low prevalence of azole resistance may be increasing, warranting further surveillance of susceptible patients.

Bacterial colonization of airway stents: a promoter of granulation tissue formation following laryngotracheal reconstruction.

OBJECTIVE: To investigate whether airway granulation, a common occurrence during laryngotracheal reconstructive surgery and a common cause of delays in definitive treatment and treatment failure, is associated with a microbial etiology. DESIGN: Prospective case-control study. SETTING: Tertiary referral airway reconstruction unit. PATIENTS: Patients who had an airway stent as part of their treatment for laryngotracheal stenosis. INTERVENTIONS: All airway stents were sent for microbiological analysis. Information about patient demographics, lesion characteristics, and presence of airway granulation tissue at different times during treatment were obtained and correlated against the microbiological findings from airway stents. MAIN OUTCOME MEASURES: A chi2 test was used to correlate airway colonization with specific pathogens and occurrence of airway granulation. Logistic regression analysis was used to identify independent microbiological predictors of airway granulation. RESULTS: Thirty-one airway stents were removed from 26 patients. The mean (SD) age at presentation was 42 (18) years, and postintubation tracheal stenosis was the most common etiology. There were highly significant associations between stent colonization with Staphylococcus aureus and Pseudomonas aeruginosa and the occurrence of airway granulation (P<.02), and these microorganisms were independently associated with the risk of developing airway granulation. Furthermore, S aureus was associated with persistence of airway granulation on average 4 months following removal of the stent. CONCLUSIONS: Airway granulation seems to be associated not with polymicrobial airway colonization but with infection with specific pathogenic microorganisms. All patients undergoing laryngotracheoplasty should receive antibiotic prophylaxis to cover these microorganisms, and the development and use of antibiotic-impregnated airway stents should be explored.

Rhinoorbital and pulmonary zygomycosis post pulmonary aspergilloma in a patient with chronic lymphocytic leukaemia.

A patient with an 18-year history of chronic lymphocytic leukaemia developed zygomycosis of the orbit, sinuses and nasal bones together with pulmonary fungal nodes due to Absidia corymbifera while on high dose steroids and four months after successful treatment of pulmonary aspergilloma with liposomal amphotericin B followed by oral voriconazole. He was treated successfully with extensive surgical debridement, intravenous liposomal amphotericin B and intravenous itraconazole.

Candidaemia in a tertiary hospital in Nigeria.

BACKGROUND: Candidaemia is a widely-studied and reviewed topic in the developed world; however, there is a dearth of information on nosocomial candidaemia in Nigeria, despite the increasing use of more invasive therapeutic modalities, immunosuppressive agents and increasing incidence of immunosuppression as a result of malignancies and HIV. OBJECTIVES: To determine the hospital-based frequency of candidaemia in a tertiary hospital in Ibadan, Nigeria. METHOD: This was a prospective descriptive study which included 230 immunosuppressed patients. All isolates were identified to the species level using both conventional and automated methods. Thereafter, all Candida species isolated were tested for antifungal susceptibility using the broth microdilution method. RESULTS: Candidaemia occurred in 12 (5.21%) of the 230 study patients, with C. tropicalis accounting for 50% of the infections. Four patients (33.3%) presented with C. parapsilosis, one (8.3%) with C. albicans and one (8.3%) with a mixed infection of C. albicans and C. tropicalis. All 12 isolates were sensitive to fluconazole (minimal inhibitory concentration < 8 mg/mL). Univariate analysis revealed that old age, multiple surgeries and long-term hospitalisation were significant contributing factors for the occurrence of candidaemia. Eleven (91.7%) of the 12 patients with candidaemia had Candida colonisation of other sterile sites including the bladder, peritoneum and trachea. Furthermore, bivariate analysis revealed that mucositis (p = 0.019) and diarrhoea (p = 0.017) were significantly associated with an increased risk of candidaemia. The crude mortality rate of candidaemia was 91.7%. CONCLUSION: This study highlights the significance of nosocomial candidaemia and the need for proactive laboratory investigation and clinical management of this life-threatening disease.

Penicillium species as a rare isolate in tracheal granulation tissue: a case series.

INTRODUCTION: Granulation tissue formation is a major problem complicating the treatment of upper airway stenosis. We present two cases of recurrent tracheal granulation tissue colonisation by Penicillium species in patients undergoing laryngotracheal reconstructive surgery for post-intubation tracheal stenosis. We believe that although most Penicillium species do not cause invasive disease they can be a contributory factor to the occurrence of upper airway stenosis. CASE PRESENTATION: A microbiological and mycological study of tracheal granulation tissue in two patients with recurrent laryngotracheal stenosis was carried out. Penicillium species was seen microscopically and cultured from tracheal granulation tissue. Neither patient grew any bacteria known to be associated with airway granulation tissue formation. Amphotericin B, itraconazole, flucytosine voriconazole and caspofungin were highly active against both isolates. CONCLUSION: A search for a fungal cause should form part of the investigation for recurrent tracheal granulation tissue during laryngotracheal reconstruction.

Environmental source of Candida dubliniensis.

We isolated Candida dubliniensis from a nonhuman source, namely, tick samples from an Irish seabird colony. The species was unambiguously identifi ed by phenotypic and genotypic means. Analysis of the 5.8S rRNA gene showed that the environmental isolates belong to C. dubliniensis genotype 1.