Aspergillus flavus

Date: 26 November 2013

cultures grown from BAL fluid showing formation of sclerotia.

Copyright:

Kindly donated by Dr Claudia Venturelli and Dr Giorgia Bertazzoni, Laboratory of Microbiology – Policlinico of Modena-Italy. © Fungal Research Trust

Notes:

These colonies were isolated from a BAL, (also with bacterial qrowth of S.aureus and S.maltophilia) from a patient with a VAP (undergoing corticosteroid treatment). The growth medium used is sabouraud dextrose agar , incubated at 37° C The identification is made by microscopic/macroscopic observation criteria.

Colonies on CYA 60-70 mm diam, plane, sparse to moderately dense, velutinous in marginal areas at least, often floccose centrally, sometimes deeply so; mycelium only conspicuous in floccose areas, white; conidial heads usually borne uniformly over the whole colony, but sparse or absent in areas of floccose growth or sclerotial production, characteristically Greyish Green to Olive Yellow (1-2B-E5-7), but sometimes pure Yellow (2-3A7-8), becoming greenish in age; sclerotia produced by about 50% of isolates, at first white, becoming deep reddish brown, density varying from inconspicuous to dominating colony appearance and almost entirely suppressing conidial production; exudate sometimes produced, clear, or reddish brown near sclerotia; reverse uncoloured or brown to reddish brown beneath sclerotia. Colonies on MEA 50-70 mm diam, similar to those on CYA although usually less dense. Colonies on G25N 25-40 mm diam, similar to those on CYA or more deeply floccose and with little conidial production, reverse pale to orange or salmon. No growth at 5°C. At 37°C, colonies usually 55-65 mm diam, similar to those on CYA at 25°C, but more velutinous, with olive conidia, and sometimes with more abundant sclerotia.

Sclerotia produced by some isolates, at first white, rapidly becoming hard and reddish brown to black, spherical, usually 400- 800 µm diam. Teleomorph not known. Conidiophores borne from subsurface or surface hyphae, stipes 400 µm to 1 mm or more long, colourless or pale brown, rough walled; vesicles spherical, 20-45 µm diam, fertile over three quarters of the surface, typically bearing both metulae and phialides, but in some isolates a proportion or even a majority of heads with phialides alone; metulae and phialides of similar size, 7-10 µm long; conidia spherical to subspheroidal, usually 3.5-5.0 µm diam, with relatively thin walls, finely roughened or, rarely, smooth.

Distinctive features

Aspergillus flavus is distinguished by rapid growth at both 25°C and 37°C, and a bright yellow green (or less commonly yellow) conidial colour. A. flavus produces conidia which are rather variable in shape and size, have relatively thin walls, and range from smooth to moderately rough, the majority being finely rough.


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Showing 10 posts of 2574 posts found.
  • Title

    Legend

  • A. Necrotic mass prolapsing in and out of the distal right intermediate bronchus obscuring both the basal stem and basal division

    Patient VE - Plugging of airways with mucus 1

  • History : A 20 yr old female with cystic fibrosis complicated by CF-related Diabetes mellitus (diagnosed at age 12 years) & ABPA (diagnosed at
    15 years ). She was fairly stable until last 9 months, when she started to experience frequent pulmonary exacerbations, which have prompted intensive therapies.
    Her serum IgE at the time of diagnosis was 5060 IU/L, skin prick test for aspergillus was positive, and serum was positive for precipitating antibodies to Aspergillus.  She was treated with oral prednisone (1 mg/kg/day) for first two weeks followed by prednisone at 0.5 mg/kg every other day for at least 6 months with some clinical and serologic improvement. Over the following 5 years, she presented with a pattern of repeated episodic exacerbations with wheezing and crackles, increases in IgE and need to increase prednisone dosage. In an attempt to control her frequent ABPA relapses, itraconazole was added at 200mg twice a day, with some clinical & serologic improvement.
     
     2-3 weeks prior to the scans and X rays, she developed severe protracted coughing spells associated with minor hemoptysis, low grade intermittent fever, and weight loss. Her FEV1 declined in a 3 months period from 56% to 33%.
     
    A chest-x ray (Fig 3) did not reveal any new changes when compared to the one obtained almost a year before. A CT scan of the chest Figs 1 and 2- lateral view), however shows an ovoid soft tissue density within an ectatic bronchi in the anterior basal segment of the LLL, felt to be an aspergilloma.

    She was started on oral voriconazole (3 months after the above scans and X-rays) which is better absorbed in CF patients than itraconazole, at 200mg twice a day. Her prednisone was gradually reduced to 5 mgs/day and her FEV1 increased to 46% of predicted (03/31/10), her IgE level was 1167 kU/L (previously in January 2009, her IgE level was  3053 kU/L)and her weight has plateaued.
    Since she was not fit enough for surgery at that time, removing the aspergilloma by flexible bronchoscopy was unsuccessful. The aspergilloma can be seen at bronchoscopy in Fig 4. 

    Go to follow up 12 months later

    Fig 1 CT scan shows cystic bronchiectasis but a classic aspergilloma with halo sign is seen in left lower lobe, Fig 2 CT - Lateral view showing aspergilloma - left lower lobe. , Fig 3 Chest X ray showing bilateral basal bronchiectasis with no definite aspergilloma., Fig 4 Aspergilloma seen on bronchoscopy.

  • Widespread mucoid impaction also seen, particularly in left side, suggestive of allergic bronchopulmonary aspergillosis.

    HR CT chest (January 2008) showing thick walled, multiloculated cavity and dilated bronchial cavities in the right upper lobe associated with cystic and varicose bronchiectasis.

  • Microscopy of fungal hyphae isolated from fungal culture (lactophenol blue)

    Chronic invasive sinus aspergillosis caused by Aspergillus terreus

  • A CT scan performed at this time showed an enhancing lesion with ill defined margins involving the pterigopalatine fossa, the maxillary antrum , orbital apex and middle cranial fossa. There was also destruction of boney architecture locally.

    Chronic invasive sinus aspergillosis caused by Aspergillus terreus

  • The patient underwent a pneumonectomy because of the severity of her disease process, and uncertainty about the diagnosis, prior to serology results being obtained.

    Serology showed an IgE of 2600, with a strongly positive Aspergillus RAST test and weakly positive Aspergillus precipitins. Material removed at bronchoscopy showed eosinophilia. These features confirm a diagnosis of allergic bronchopulmonary aspergillosis (ABPA).

    Image A. Her chest x-ray (Oct 04) shows consolidation of her left lower lobe with slight mediastinal shift, but some diaphragmatic elevation., Image B. Progression of the process was documented in Dec (04) by chest x-ray, and bronchoscopy had not identified a malignant lesion. , Image C. CT scan of the chest (Oct 04) shows extensive collapse of the left lung with only slight aeration of the left upper lobe. No definite central mass can be identified and no lymphadenopathy was visible. There is a small left sided pleural effusion. The right lung is normal. “The overall appearances remain highly suspicious of a central broncho-occlusive lesion on the left side., Image D. CT scan of the chest (Oct 04) shows extensive collapse of the left lung with only slight aeration of the left upper lobe. No definite central mass can be identified and no lymphadenopathy was visible. There is a small left sided pleural effusion. The right lung is normal. “The overall appearances remain highly suspicious of a central broncho-occlusive lesion on the left side., Image E. Cut surface of lung, following pneumonectomy, showing massive mucous impaction of the major airways and almost complete distal consolidation., Image F. Mucous containing Charcot-Leyden crystals, stained with H & E, Image G. Sheets of eosinophils , Image H. Bronchial mucosa under H & E stain showing numerous eosinophils deep to the mucosa, and mucus in the lumen of the bronchiole., Image I. Grocott (silver) stain showing branching septate hyphae fairly typical of Aspergillus in mucus. The apparent right angle branching is unusual (Low power mag.)., Image J. Grocott (silver) stain showing branching septate hyphae fairly typical of Aspergillus in mucus. The apparent right angle branching is unusual (High power mag.)..