Robert Pritchard

BLACK FUNGI: A SURVEY OF DEMATIACEOUS HYPHOMYCETES FROM CLINICAL SPECIMENS IDENTIFIED OVER A FIVE YEAR PERIOD IN A REFERENCE LABORATORY

&NA; Five hundred and fifty six dematiaceous hyphomycetes, the great majority referred from other laboratories, were identified by us over a five year period. Of these, thirty five were regarded as being of probable pathogenetic significance. These included seven isolates associated with chromoblastomycosis, and seven isolates thought to be causing phaeohyphomycosis. There were six strains of Phaeoannellomyces werneckii and five strains of Sporothrix schenckii. Seven isolates, all strains of Aureobasidium pullulans, were associated with fungal peritonitis in patients on chronic ambulatory peritoneal dialysis. Two Bipolaris isolates were associated with paranasal sinus fungus ball, a condition in which no evidence of tissue invasion by fungi could be found, even though pressure necrosis of bone could lead to very serious consequences. A further seven dematiaceous hyphomycetes, isolated from cases of paransal fungus ball, keratitis and otitis externa, were thought to be of possible pathogenetic significance. Of the remaining 514 isolates thought to be of no pathogenetic significance, two thirds were made up of strains of Aureobasidium pullulans, Alternaria alternata, Cladosporium cladosporioides, Epicoccum purpurascens and Phoma species. In many cases it was thought that the referring laboratories had allowed insufficient time for development of conidiogenesis in these strains, before sending them to our laboratory for identification.

Increasing importance of Trichophyton tonsurans in childhood tinea in New South Wales. The pattern of childhood tinea in New South Wales, Australia 1979-1988: the emergence of Trichophyton tonsurans as an important pathogen in tinea capitis in white children.

A retrospective study was undertaken of 192 cases of culture proven tinea capitis occurring between 1979 and 1988 in a predominantly white population of children in New South Wales (NSW). The aim of the study was to identify whether Trichophyton tonsurans was increasing in importance in the causation of this condition in Australia as it was in many other parts of the world. The results of our study were compared with those of earlier Australian studies. Our study demonstrated that Trichophyton tonsurans is now equal in importance to Microsporum canis which was previously the strongly predominant organism.

Trichosporon beigelii: survey of isolates from clinical material

&NA; Two hundred and eight isolates of Trichosporon beigelii were identified over the period January 1973 to July 1983. 45.7% of these were from skin, 25.0% from nail, 22.6% from tissues and fluids, 3.4% from hair and 3.4% from sputum. Tr. beigelii was isolated in association with a recognized pathogen in 23 cases, 9 with a yeast, 14 with a dermatophyte. In 38 cases, Tr. beigelii was the only organism isolated when direct microscopic examination of clinical material showed the presence of hyphae and/or yeast cells. Although Tr. beigelii could only be assigned a definite pathogenic role in 6 cases of genital white piedra, and in one case of peritonitis associated with chronic ambulatory peritoneal dialysis, we believe that this organism was pathogenic in many cases of skin infection. In most of the cases where it was isolated from tissue or fluids at Royal North Shore Hospital, Tr. beigelii was not considered to be significantly contributing to the disease process.

Phaeohyphomycotic Soft Tissue Infections Caused by the Coelomycetous Fungus Microsphaeropsis arundinis

ABSTRACT Microsphaeropsis arundinis is an anamorphic fungal plant inhabitant belonging to the form class Coelomycetes. We describe two cases of M. arundinis soft tissue infections in immunosuppressed patients. This organism has not previously been described as causing disease in humans. It was identified on the basis of its typical ostiolate pycnidial conidiomata, ampulliform conidiogenous cells, and small, smooth-walled, brown, cylindrical conidia.

Dermatophytes Identified at the Australian National Reference Laboratory in Medical Mycology 1966–1982

Summary Over a 17 yr period from 1966 to 1982,4354 dermatophytes were identified at the Australian National Reference Laboratory in Medical Mycology. The most frequently identified species was Trichophyton rubrum, accounting for 35.3% of identifications, followed by Trichophyton mentagrophytes (26.5%), Trichophyton tonsurans (12.8%), Epidermophyton floccosum (10.7%) and Microsporum canis (8.4%). Specimens taken from the feet were the most common source of the Trichophyton rubrum isolates, followed by specimens from the groin. The highest incidence of T. rubrum and other Trichophyton infections was found in males in the age group 21–30 yr. Microsporum species were most commonly isolated from children aged 10 yr or less. In 1.5% of specimens, more than one fungal species was isolated. In most of these instances a yeast (predominantly Candida species) was found in addition to a Trichophyton species.

SPOROTHRIX SCHENCKII—INCIDENCE IN THE SYDNEY REGION

Sporothrix schenckii is a fungus which occurs in soil and on plant material. It has not often been reported in Australia from clinical sources. Most reports have been from Queensland, and it has rarely been reported from the Sydney and Newcastle Metropolitan areas. Twelve isolations from the Sydney area are reported.

Isolation and identification of Burkholderia cepacia by participants in an external Quality Assurance Program (QAP) between 1994 and 1999

Aim: External quality assurance programs (QAPs) provide an opportunity to benchmark laboratory performance according to the profile of specimens received. Participant confidentiality is maintained within each group of laboratories whose performance is measured using similar, repetitive exercises. Isolation and identification of Burkholderia cepacia from simulated cystic fibrosis (CF) sputa was a clinically relevant exercise that provided a model for this analytical approach. Methods: Between 1994 and 1999, six Royal College of Pathologists of Australasia (RCPA) Microbiology QAPs included four simulated CF sputa and two panels of oxidative Gram‐negative bacilli. Laboratories were grouped according to experience with CF sputa disclosed by two questionnaires. Data were analysed by laboratory group for ability to isolate and identify B. cepacia. Results: Three laboratory groups annually received >100 CF sputa (CF>100), 100 CF sputa or fewer, or did not regularly receive CF sputa. CF>100 laboratories inoculated more isolation media, were more likely to use selective media and were less likely to misidentify B. cepacia than the other groups. Improved performance by CF>100 laboratories was marked after the first exercise and remained at a high level compared with the other two groups. This trend in performance was also apparent for Pseudomonas aeruginosa although the numbers of errors were less than for B. cepacia. Conclusions: These exercises demonstrated consistently improved performance only among CF>100 laboratories. The future criteria for laboratory accreditation may include performance as well as participation in QAPs, placing additional burdens on organisers and participants.

Antimicrobial susceptibility tests: for better or worse

Summary Microbiology laboratories devote a great deal of effort to the in vitroinvestigation of antibiotics. In the U.K., U.S.A. and in Australia external quality assurance programmes concern themselves with these efforts, and their conclusions have been discussed in recent papers.1,2Data are also available from the RCPA programme in microbiology. The most frequent of these investigations is the antibiotic susceptibility test, which gives us information on the in vitroactivity of an antimicrobial agent against a bacterium under standard conditions, information which experience has shown to correlate with performance in vivo. A number of methods are available for susceptibility testing (ST): agar (disc) diffusion, agar dilution, broth dilution and, recently, semi‐automated techniques using machines which yield answers more rapidly than the conventional methods.

External quality assurance in microbiology. The programme of the Royal College of Pathologists of Australasia.

Summary Since 1967 the Royal College of Pathologists of Australasia has been providing an external quality assurance programme in microbiology. The number of participants has risen from 70 to 222, and the samples distributed for investigation have increased in quantity, now totalling 35‐40 per annum, and in variety, so that most aspects of clinical microbiology are now touched on. In recent years clerical accuracy and the adequacy of reports have been examined. However, more emphasis is needed on the stability of the specimens (freeze‐drying will be introduced soon), the assessment of a laboratorys general performance, the standardization of methods and the educational aspects of external quality control.

Clinching the Diagnosis — Sputum and Other Specimens in Respiratory Tract Infection

Summary Routine sputum culture in microbiology laboratories is frequently a source of dissatisfaction to microbiologists and clinicians alike. Care should be taken to ensure that the investigations requested are appropriate and that an adequate specimen is collected. Co‐operation between the microbiologist and the clinician is required if the laboratorys facilities are to be properly exploited for the etiological diagnosis of respiratory tract infection. In clinical conditions such as lung abscess and atypical pneumonia sputum is not an appropriate specimen for the laboratory to work on and early consideration should be given to obtaining lower respiratory tract secretions free of oropharyngeal contamination.