Development of totally enclosed slide culture medium and its application in filamentous fungi culture / 临床检验杂志

Objective To develop a safe,practical,disposable slide culture medium for fungi culture.Methods Based on the principle of traditional slide culture medium with small steel ring,a plate of polyvinyl chloride (PVC) with high transparency was chosen as the bottom material of the new medium which held the size of the conventional slide (25.2 mm × 75.9 mm × 1.05 mm) with frosted design at both ends.The diameter of inoculation hole was 2.4 mm on the rounded culture dish which was designed with diameter of 19.4 mm and side height of 3.75 mm.The users could inject potato dextrose agar (PDA) or other medium into the culture dish as needed and then sealed it with a plug.The upper cover was prepared with toughened glass.The improved disposable slide culture medium should be kept in humidifying box with sponge strips in the water tanks of both sides and sealed with cap.The growth status,microscopic morphology and staining result of filamentous fungi in the totally enclosed slide culture medium were observed and the preservative status of the prepared medium was also monitored simultaneously.Results The effects of the improved slide culture medium were satisfactory in clinical practical application.The growing status of fungi could be observed visually and the pigment was clear.The original growth form of fungi could be monitored under microscope and dye material could be perfused directly to stain with good results.The appearance and the volume of packaged slide medium were unchanged after preservation at 4 ℃ for 3 months.Conclusion An improved slide culture medium was successfully developed,which should be easy to operate,high visible,satisfactory for sealing effects and reliable for culture performance with high biological safety.The growth status of fungi could be observed under microscope at any time,and the medium could also be monitored under oil immersion lens directly and stained with cotton blue.The improved medium could be used in morphological examination for fungi in different levels of medical laboratories since its favorable results in clinical application.

Prevalence Of Tinea Capitis In A Tertiary Care Hospital,North India

Fungal infections are common in humans worldwide. Hot and humid weather conditions in the tropical countries like India make humans very susceptible to fungal infections. Tinea capitis (TC) is the superficial fungal infection of the scalp and hair. The true incidence of Tinea capitis is unknown. although infection can occur at any age.Tinea capitis is one of the most common infectious conditions in children worldwide.Atotal of 100 subjects were enrolled in study who were attending Dermatology Out Patient Department (OPD) in a tertiary care hospital.Hair sample was taken and culture was done on Sabouraud's Dextrose Agar(SDA).Species identification was done by slide culture.T.tonsurans was most common isolate.

Heat fixed but unstained slide smears are infectious to laboratory staff.

Background and Aim: In a clinical microbiology laboratory, heat fixed slide smears are commonly transported from one place to another for staining with different stains and also for onsite proficiency testing of laboratory technicians for accreditation of the laboratories. These smears are frequently handled without gloves by the staff in developing countries. Therefore, this study was conducted to check the survivability of tubercle bacilli on smears after physical and chemical treatments. Methods: A total of 196 AFB positive smears were analyzed. Of these, 116 were stained with Ziehl Neelsen (ZN), 60 with cold Kinyoun and 10 were unstained but heat fixed and 10 were neither stained nor heat fixed. The last 20 smears served as controls. The ZN and Kinyoun stained smears were 0-1.5-year-old and stored at room temperature in slide boxes, while control smears were freshly prepared. All smears were prepared from sputum samples positive for acid fast bacilli. All four sets were subjected to slide culture to see if mycobacteria could survive and grow in any. For slide culture, a new and safe device was used, which is designed for three in one purpose: cell cultivation, direct observation of the growth under microscope and cell harvesting inside the closed tube. The slide smears were directly dipped into this tube that contained liquid culture medium. The tubes were incubated at 370C for four weeks. The growth, if any, was confirmed by MPT-64 rapid test and subculture on LJ slants. Results: No growth was observed in ZN and Kinyoun stained slide smears. However, significant growth was observed in both control sets; the unstained non heat fixed as well as heat fixed slide smears. Conclusions: The results of our study indicate that tubercle bacilli remain viable even after heat fixation and carry risk of infection by contact. However, stained smears are safe for handling and storage.

Yeast identification in routine clinical microbiology laboratory and its clinical relevance.

Rapid identification of yeast infections is helpful in prompt appropriate antifungal therapy. In the present study, the usefulness of chromogenic medium, slide culture technique and Vitek2 Compact (V2C) has been analysed. A total of 173 clinical isolates of yeast species were included in the study. An algorithm to identify such isolates in routine clinical microbiology laboratory was prepared and followed. Chromogenic medium was able to identify Candida albicans, C. tropicalis, C. krusei, C. parapsilosis and Trichosporon asahii. Chromogenic medium was also helpful in identifying "multi-species" yeast infections. The medium was unable to provide presumptive identification of C. pelliculosa, C. utilis, C. rugosa, C. glabrata and C. hemulonii. Vitek 2 compact (V2C) differentiated all pseudohypae non-producing yeast species. The algorithm followed was helpful in timely presumptive identification and final diagnosis of yeast infections, including multi-species yeast infections.

Paraffin slide culture technique for isolating non-tuberculous mycobacteria from stool and sputum of HIV sero-positive patients.

Objective: Paraffin slide culture method (PSC) was used to isolate Non-tuberculous mycobacteria (NTM) from stool and sputum samples of HIV seropositive and negative patients. Material & Methods: Eighty stool and forty two sputum samples from both symptomatic or asymptomatic HIV sero-positive patients; and 40 stool and 128 sputum samples from symptomatic but HIV seronegative patients were cultured by PSC to assess its utility in isolating NTM from the clinical specimens. The samples were simultaneously processed by culture on Lowenstein Jensen (LJ) medium for comparison with regard to isolation rate, isolation time and contamination rate. Results: The PSC proved to be as good as LJ in isolating NTM from clinical specimens and, in addition, had the advantage of in situ staining for acid fast bacilli and lower contamination rate. The PSC was also used for typing NTM by biochemical tests.