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D W Denning

Publications and source records attributed to D W Denning.

At least 19 recordsLinked to original sources
PubMed1999

Aspergillus fumigatus catalases: cloning of an Aspergillus nidulans catalase B homologue and evidence for at least three catalases.

The presence of catalases in the water soluble fractions of three Aspergillus fumigatus strains was investigated using non-denaturing and denaturing polyacrylamide gel electrophoresis and Western analysis. Using non-denaturing polyacrylamide gel electrophoresis and staining for catalase activity, three separate catalases were identified. An A. fumigatus catalase gene (catB) was cloned from genomic DNA using the Aspergillus niger catR gene as a probe. Polyclonal antibodies were raised to a glutathione S-transferase-CatB fusion product expressed in Escherichia coli. Western analysis indicated that, under denaturing conditions, the polyclonal antibody recognised a 90-kDa band and under non-denaturing conditions, two separate bands were identified. These results indicate that A. fumigatus in addition to CatB, produces at least two other catalases, one of which is similar in size to CatB. The polyclonal antibody was also used to observe catalase expression in mice, experimentally infected with A. fumigatus. Staining was observed heterogeneously throughout the fungal hyphae. This result indicates that catalase is produced by A. fumigatus during invasive aspergillosis.

Animals↗
PubMed1998

Influenza-like episodes in HIV-positive patients: the role of viral and 'atypical' infections.

OBJECTIVES: To document viral and 'atypical' infections in HIV-positive patients and association with influenza-like symptoms. PATIENTS AND METHODS: Monthly culture of urine, faeces and throat swabs in 63 HIV-positive patients (30 asymptomatic and 33 with AIDS-related complex/AIDS) over 5-27 months (with 1125 patient-months of follow-up), with further sample collections during influenza-like episodes. Standard viral detection methods were used. Throat swabs were assessed for Chlamydia sp. by culture and immunoblotting, and for Mycoplasma pneumoniae by polymerase chain reaction. RESULTS: Viruses were detected in 15 (50%) and M. pneumoniae in nine (30%) out of 30 HIV-positive patients during an influenza-like illness. A close temporal relationship with symptoms was observed in 12 (40%) patients: cytomegalovirus in six (20%), M. pneumoniae in three (10%), herpes simplex virus in three (10%), and enterovirus in one (4%). Influenza-like symptoms were more frequent in asymptomatic HIV infection than in AIDS-related complex/AIDS patients (actuarial risk at 1 year, 63 versus 26%; P=0.002), particularly in those with CD4 cell counts >300 x 10(6)/l at enrolment (P=0.002). At least 44% (four out of nine) M. pneumoniae infections were asymptomatic and 78% (seven out of nine) were associated with prolonged excretion (2-17 months). Chlamydia sp. were not detected. CONCLUSIONS: Influenza-like symptoms were more likely to be reported by HIV-positive patients at early stages of disease, possibly as a result of differences in immune responses to viral infection. There was a close association in 40% of cases between the development of symptoms and detection of cytomegalovirus, herpes simplex virus, enterovirus and M. pneumoniae (a previously unrecognized association).

AIDS-Related Opportunistic Infections↗
PubMed1998

Treatment of HIV-related fluconazole-resistant oral candidosis with D0870, a new triazole antifungal.

OBJECTIVES: To evaluate the efficacy and tolerance of D0870 in the treatment of HIV-related fluconazole-resistant oro-oesophageal candidosis. DESIGN: Multicentre open study. PATIENTS: HIV-seropositive patients with oro-oesophageal candidosis despite at least 7 days of treatment with fluconazole at doses of 100 mg per day or more. METHODS: Patients received an initial dose of D0870 (150 mg), then 25 mg per day for 6 days. Symptoms and signs of candidosis were compared at entry and on days 3 and 7 of treatment. At each visit, samples were taken for safety monitoring and for in vitro susceptibility testing of Candida isolates. Limited pharmacokinetic samples were taken on days 1 and 7. RESULTS: Of 26 evaluable patients, 16 showed partial improvement, nine showed no improvement, and only one had full clearance of thrush by day 7. In vitro testing of the cleared patient's isolate suggested that it was susceptible to fluconazole. Symptoms of dysphagia cleared in 14 and improved in five of the 22 patients with presumptive oesophageal involvement at entry. Pharmacokinetic measurement showed wide variability in maximum D0870 levels recorded on day 1 (range, 0.07-0.34 mg/l) and susceptibility testing of isolates also showed a range of minimal inhibitory concentration values to D0870 (range, < 0.06-8 mg/l; median, 0.25 mg/l). When these data were combined with clinical response there was a strong suggestion that lack of symptomatic improvement was related to low plasma D0870 levels or to the presence of less D0870-susceptible isolates. Six patients were noted to have a fall in haemoglobin, three of whom were receiving concomitant therapy known to suppress bone marrow. Three patients reported headaches as adverse events that were attributed to study medication, but D0870 was well tolerated overall. CONCLUSIONS: D0870 shows promise in the treatment of fluconazole-resistant oro-oesophageal candidosis and was well tolerated, although efficacy in this difficult-to-treat patient group was probably limited due to the inadequate plasma levels achieved in this pilot study with the low doses of D0870 administered.

AIDS-Related Opportunistic Infections↗
PubMed1998

An EORTC multicentre prospective survey of invasive aspergillosis in haematological patients: diagnosis and therapeutic outcome. EORTC Invasive Fungal Infections Cooperative Group.

OBJECTIVES: The EORTC Invasive Fungal Infections Cooperative Group (IFICG) conducted a prospective survey by questionnaire of all cases of invasive aspergillosis (IA) in cancer patients to ascertain current diagnostic and therapeutic approaches. METHODS: All members of the IFICG were asked prospectively to complete a detailed questionnaire for each IA case identified in their institution over a 12-month period. RESULTS: One hundred and thirty questionnaires were returned. All cases were independently evaluated (DWD & JC) and 123 were eligible. Cases came from 20 hospitals in eight countries and the number of cases per institution varied from 1-21. Acute myeloid leukaemia (AML) (60, 49%), acute lymphoblastic leukaemia (ALL) (21, 17%) and lymphoma (11, 9%) were the most frequent underlying diseases, and 16 (12%) patients had received an allogeneic bone marrow transplant. Pulmonary involvement was present in 87%, infection of sinuses/nose in 16% and brain in 8%. The chest radiograph was initially normal in 9% of those with primary pulmonary disease. The diagnosis was confirmed in 50%, probable in 31% and possible in 19%. The evidence for IA was on the basis of clinical and radiological features alone in 28%, with culture or histology in another 31% and 9%, respectively, and with both culture and histology in 29%. In three (2%) patients with diagnosis was based on culture or histology alone. Treatment was given to 120 patients (98%)-amphotericin B 75%, lipid-associated amphotericin B 36%, itraconazole 40%, flucytosine 12%, growth factors 33%, lobectomy 5%. At 3 months after diagnosis or first suspicion of IA, 44 (36%) patients were alive and 79 (64%) dead. Outcome was best in those with AML (30% death and 46% with a complete antifungal response or cure). Growth factors (mostly granulocyte colony stimulating factor) appeared not to influence outcome (P = 0.99). CONCLUSION: IA remains a considerable diagnostic and therapeutic challenge. No single diagnostic procedure was universally successful and a multifaceted approach including surgery is necessary. There was no discernable difference in outcome between initial therapy with amphotericin B, itraconazole or lipid-associated amphotericin B, although numbers are limited and the study was retrospective.

Adolescent↗
PubMed1998

Variation in morphotype, karyotype and DNA type of fluconazole resistant Candida albicans from an AIDS patient.

Azole-resistant oropharyngeal and oesophageal candidiasis is a recent phenomenon observed in patients with AIDS usually previously treated with fluconazole. Some variation has been observed in antifungal susceptibility testing among separate colonies of Candida albicans from the same patient. This raises the question of whether there are multiple clones present or simply phenotypic variation in expression of azole resistance. To address this question we took 18 isolates grown from multiple swabs taken before and after experimental azole therapy from a single HIV-positive individual with fluconazole-resistant oral candidiasis and compared morphotype, karyotype, PCR-based DNA typing and azole susceptibility. Ten of the isolates were from a single 2-day period. Amongst these 10 there were seven morphotypes, five karyotypes and four polymerase chain reaction (PCR) types. Three further morphotypes, one karyotype and two PCR types were found amongst the eight isolates obtained during the subsequent 4 months. Limited variation in susceptibility to two azoles--fluconazole and D0870--was also seen. This work emphasizes both the large genotype and phenotypic variability of C. albicans isolates in the mouth of AIDS patients with fluconazole resistance, and the difficulties in interpretation of present typing methods.

AIDS-Related Opportunistic Infections↗
PubMed1998

Skull base osteitis following fungal sinusitis.

Aspergillus sp. sinusitis is not uncommon in immunocompromised patients but is unusual in patients who are not immunocompromised. The disease may occur as a saprophytic condition, as an allergic sinusitis or as a potentially lethal invasive disease. The differentiation between non-invasive and invasive Aspergillus sp. sinusitis is crucial and this distinction is fully discussed. The treatment options are also considered. Invasive disease requires aggressive treatment with long-term antifungal agents in sufficient doses combined with wide surgical excision. We present a patient who presented with invasive Aspergillus fumigatus sinusitis and subsequently developed cranial neuropathies and skull base osteitis. She was initially treated with oral itraconazole (400 mg daily) for 18 months but due to lack of response this was changed to a new experimental oral azole (voriconazole) which was continued for a further 14 months. She has since remained well for the last five years.

Adult↗
PubMed1998

In-vitro activity of voriconazole against Aspergillus spp. and comparison with itraconazole and amphotericin B.

The in-vitro activity of the triazole antifungal agent voriconazole was compared with itraconazole and amphotericin B against 60 aspergillus isolates. Susceptibility tests were performed using two methods: a macrodilution and a microdulution method. For macrodilution methodology, geometric mean (GM) MIC values and ranges were 0.4 and 0.125-4 mg/L for voriconazole, 0.24 and 0.06-->16 mg/L for itraconazole, and 1.04 and 0.5-4 mg/L for amphotericin B. For the microdilution method, GM MICs and ranges were 0.66 and 0.125-2 mg/L for voriconazole, 0.27 and 0.06-->16 mg/L for itraconazole, and 1.62 and 0.25-32 mg/L for amphotericin B. In conclusion, voriconazole is active against Aspergillus spp. in vitro, and at similar concentrations to itraconazole.

Amphotericin B↗
PubMed1998

In-vitro activities of amphotericin B, itraconazole and voriconazole against 150 clinical and environmental Aspergillus fumigatus isolates.

The in-vitro activity of amphotericin B, itraconazole and voriconazole against 130 clinical and 20 environmental Aspergillus fumigatus isolates was tested with an agar dilution method using RPMI 1640 medium. Itraconazole-susceptible (AF71) and -resistant (AF90) isolates were included in each test and all isolates were tested in duplicate. Geometric mean MIC values (ranges) at 48 h and 72 h were, respectively, amphotericin B, 0.91 (0.25-2) and 1.50 (1-4) mg/L; itraconazole, 0.25 (0.06-1) and 0.48 (0.125-8) mg/L; and voriconazole, 0.56 (0.25-8) and 0.78 (0.25-8) mg/L. The reproducibility of the results was high for all drugs. In-vitro resistance of A. fumigatus to the tested antifungal agents was uncommon and the MICs of itraconazole were half those of voriconazole (P < 0.01).

Amphotericin B↗
PubMed1998

In vitro activity of the echinocandin antifungal agent LY303,366 in comparison with itraconazole and amphotericin B against Aspergillus spp.

LY303,366 (LY) is a novel derivative of the echinocandin class of antifungal agents. The in vitro activities of LY, itraconazole (ITZ), and amphotericin B (AMB) were assessed against 60 Aspergillus isolates, including 35 isolates of A. fumigatus, eight isolates of A. terreus, eight isolates of A. flavus, eight isolates of A. niger and one isolate of A. nidulans. Four A. fumigatus isolates were resistant to ITZ. Susceptibility testing for all drugs was performed with a broth microdilution procedure. LY was tested in two media: antibiotic medium 3 (AM3) and Casitone with 2% glucose (CAS) with an inoculum of 2 x 10(3) spores/ml. ITZ and AMB were tested in RPMI 1640 with 2% glucose with an inoculum of 1 x 10(6) spores/ml. All tests were incubated at 37 degrees C for 48 h. A novel end point was used to determine a minimal effective concentration (MEC) for LY, i. e., almost complete inhibition of growth save a few tiny spherical colonies attached to the microplate. MICs were measured for ITZ and AMB with a no-growth end point. Ranges and geometric mean (GM) MECs were from 0.0018 to >0.5 and 0.0039 mg/liter and from 0.0018 to >0.5 and 0.008 mg/liter for LY in AM3 and LY in CAS, respectively. Differences between species were apparent, with A. flavus being significantly less susceptible to LY than any other species tested with both media (P </= 0.05). Ranges and GM MICs were from 0.125 to >16 and 0.7 mg/liter for ITZ and from 0.25 to 16 and 1.78 mg/liter for AMB. Minimal fungicidal concentrations (MFCs) were also determined for all drugs. GM MFCs were 0.018, 0.09, 19.76, and 12.64 mg/liter for LY in AM3, LY in CAS, ITZ, and AMB, respectively. LY in AM3 and LY in CAS were fungicidal for 86.7 and 68% of isolates, respectively (98% killing). In comparison, ITZ and AMB were fungicidal for 35 and 70% of isolates, respectively (99.99% killing). A reproducibility study was performed on 20% of the isolates. For 12 isolates retested, the MEC or MIC was the same or was within 1 dilution of the original value for 11, 11, 10, and 9 isolates for LY in AM3, LY in CAS, ITZ, and AMB, respectively. In conclusion, LY seems to be a promising antifungal agent with excellent in vitro activity against Aspergillus spp.

Amphotericin B↗
PubMed1998

Efficacy of LY303366 against amphotericin B-susceptible and -resistant Aspergillus fumigatus in a murine model of invasive aspergillosis.

LY303366 is a novel antifungal echinocandin with excellent in vitro activity against Aspergillus spp. We compared four doses (1, 2.5, 10, and 25 mg/kg of body weight) of LY303366 with amphotericin B (0.5 to 5 mg/kg) in a temporarily neutropenic murine model of invasive aspergillosis against an amphotericin B-susceptible (AF210) and an amphotericin B-resistant (AF65) Aspergillus fumigatus isolate based on in vivo response. Mice were immunosuppressed with cyclophosphamide (200 mg/kg) and infected 3 days later. Treatment started 18 h after infection and lasted for 10 days. LY303366 was given once daily intravenously for 10 days, and amphotericin B (at 0.5, 2, and 5 mg/kg) was given once daily intraperitoneally for 10 days, or only on days 1, 2, 4, and 7 (at 5 mg/kg). Kidneys and lungs from survivors were cultured on day 11. Control mice in both experiments had 90 to 100% mortality. Amphotericin B at 0.5 mg/kg and LY303366 at 1 mg/kg yielded 10 to 20% survival rates for mice infected with either AF210 or AF65. Amphotericin B at 2 and 5 (both regimens) mg/kg yielded a 70 to 100% survival rate for mice infected with AF210 but a 10 to 30% survival rate for mice infected with AF65 (P = 0.01 to 0.04 compared with AF210). Against AF210 and AF65, LY303366 at 2.5, 10, and 25 mg/kg produced a survival rate of 70 to 80%, which was as effective as amphotericin B for AF210, but superior to amphotericin B for AF65 (P < 0.03 to 0.0006). For AF65, LY303366 at 10 and 25 mg/kg/day was superior to amphotericin B at 2 and 5 mg/kg/day in reducing tissue colony counts (P = 0.01 to 0.003), and for AF210, amphotericin B at 5 mg/kg/day and at 5 mg/kg in four doses was more effective than all four regimens of LY303366 in reducing renal culture counts (P = 0.01 to 0.0001). The present study shows, for the first time, that in vivo resistance of A. fumigatus to amphotericin B exists, although this could not be detected by in vitro susceptibility assays. Furthermore, LY303366 appears to be effective against amphotericin B-susceptible and -resistant A. fumigatus infection in this model and should be further evaluated clinically.

Amphotericin B↗
PubMed1998

Polar lipids of Aspergillus fumigatus, A. niger, A. nidulans, A. flavus and A. terreus.

Little is known of the phospholipid composition of Aspergillus species. The aim of this study was to determine individual phospholipid analogues in Aspergillus. Twenty-nine clinical and environmental isolates from five Aspergillus species were analysed. Fast atom bombardment mass spectrometric data were considered in two ranges, m/z 190-500 and m/z 500-1000, to facilitate the recognition of major fatty acyl groups and phospholipids. Quantitative comparison of major anions in both m/z ranges was undertaken. Confirmation of major phospholipid anions from eight representative isolates was achieved by tandem mass spectrometry. The major phospholipid families were phosphatidic acid (PA), phosphatidylethanolamine (PE), phosphatidylinositol (PI), and phosphatidylserine (PS). Anions were detected consistent with the presence of specific phospholipid moieties, such as palmitoyl-linolenoyl phosphatidic acid, palmitoyl-oleoylphosphatidylethenolamine, oleoyl-linoleoyl-phophatidylserine and palmitoyl-linoleoyl-phosphatidylinositol. It appears that there is some commonality of sn1 or sn2 fatty acyl substituents, frequently C18:2 at sn1 accompanied by C16:0 at sn2, with differing molecular weights being attributable to analogues with differing head groups. Differences in certain phospholipids (e.g. minor peak with m/z 933) were detected between A. fumigatus, A. nidulans and other species examined which could have diagnostic value.

Aspergillus↗
PubMed1998

Current trends in the detection of antigenaemia, metabolites and cell wall markers for the diagnosis and therapeutic monitoring of fungal infections.

There have been several recent developments in the diagnosis of fungal infections, including the production of novel antigen detection tests, the G-test, and assays for the detection of fungal metabolites. In this article we present an overview of these developments and examine the value of including these tests in clinical trials.

Antigens, Fungal↗
PubMed1997

Azole resistance in Candida.

Resistance of Candida to azoles is an increasing problem. Susceptibility testing of Candida against fluconazole and ketoconazole is now feasible and desirable. Good correlation of resistance in vitro with clinical failure of fluconazole therapy has now been shown in mucosal candidiasis. The relationship, if any, between resistance and clinical failure in the context of invasive candidiasis is not clear at present and additional correlative work needs to be done. Monitoring of resistance trends in Candida is clearly important now.

Antifungal Agents↗
PubMed1997

Guidelines for the investigation of invasive fungal infections in haematological malignancy and solid organ transplantation. British Society for Medical Mycology.

Invasive fungal infections are increasing in incidence and now affect as many as 50% of neutropenic/bone marrow transplant patients and 5 to 20% of solid organ transplant recipients. Unfortunately, many of the diagnostic tests available have a low sensitivity. The guidelines presented here have been produced by a working party of the British Society for Medical Mycology in an attempt to optimise the use of these tests. The yield of fungi from blood cultures can be increased by ensuring that at least 20 ml of blood are taken for aerobic culture, by using more than one method of blood culture, and by employing terminal subculture if continuous monitoring systems are used with a five-day incubation protocol. Skin lesions in febrile neutropenic patients should be biopsied and cultured for fungi. The detection of galactomannan in blood or urine is of value in diagnosing invasive aspergillosis only if tests are performed at least twice weekly in high-risk patients. Antigen detection tests for invasive candidiasis are less valuable. Computed tomography scanning is particularly valuable in diagnosing invasive pulmonary fungal infection when the chest radiograph is negative or shows only minimal changes. Bronchoalveolar lavage is most useful in patients with diffuse changes on computed tomography scan. The major advances in the diagnosis of invasive fungal infection in patients with haematological malignancy or solid organ transplantation have been in the use of imaging techniques, rather than in the development of new mycological methods in the routine laboratory.

Algorithms↗
PubMed1997

In-vitro activity of D0870, a new triazole antifungal drug, in comparison with fluconazole and itraconazole against Aspergillus fumigatus and Candida krusei.

The activity of the new triazole antifungal D0870 was compared with those of itraconazole and fluconazole against Candida krusei and Aspergillus fumigatus, two fungi showing inherent tolerance of fluconazole. The activity of D0870 resembled that of itraconazole against whole cells of C. krusei, but it was less effective against A. fumigatus. However, the effect on sterol biosynthesis, in terms of the sterol type accumulating and IC50 for in-vitro biosynthesis, appeared similar in both species. The superior antifungal effect of D0870 over fluconazole appeared related to better inhibition of ergosterol biosynthesis in A. fumigatus, but in C. krusei this did not account for the entire difference which may result mainly from reduced efflux of drug.

Antifungal Agents↗