Background: Potassium hydroxide（KOH）examination is commonly used in dermatological practice. Despite its simplicity, rapidity, and minimal invasiveness, experience in specimen collection, preparation, and interpretation is extremely important. Aims: To determine the ability to interpret KOH examination of six microscopists with different levels of experience within the Department of Dermatology. Methods: Six volunteer microscopists, who have different experiences in KOH examination in terms of specimens per week（SPW）, were assigned to prepare and examine 10 unknown slides of skin scrapings. All participants were then paired into three groups and exchanged the slides set to their partner in each group for a second round of slides interpretation. Results: Results of examinations were classified as correct, false negative, false positive, and misinterpretation. The highly experienced microscopists achieved more correct answers than the fairly experienced group in both sessions. There was a significant positive correlation between SPW（r=1.0, Spearman rank, p=0.01）and the correct answers; and a significant negative correlation between SPW and misinterpretation（r= -1.0, Spearman rank, p<0.01）, exclusively for the second session. Limitations: A small number of volunteer microscopists was enrolled in this study. Conclusions: Experience in routine slide examination and time spent during examination were significant factors for accurate interpretation of KOH examination. Positive correlation between experience and correct answers, and negative correlation between experience and misinterpretation were particularly observed under limited examination time.
A 68-year-old male plasterer with no history of trauma presented to our clinic in March 2012 with a 16×14-mm ulcer that developed following a crushed small papule on the right anterior chest. In April 2012, the patient was referred to another hospital, where cutaneous cryptococcosis was diagnosed based on discharge culture results. The patient was treated with oral itraconazole at a dose of 150 mg/day for 10 weeks; however, the ulcer remained unchanged and he discontinued the treatment. In May 2014, when he revisited our clinic, the ulcer with crust had grown to 29×13 mm. No regional lymph node swelling was noted. India ink staining showed a yeast-like fungus with a thick, clear capsule. A cream-colored, viscous yeast-like colony was observed on Sabouraud dextrose agar. Genetic testing identified the isolate as Cryptococcus neoformans serotype A. The patient was negative for serum cryptococcal antigen. Neither chest radiography nor computed tomography revealed any abnormalities. The patient had no underlying disease. Oral fluconazole (400 mg/day for 12 weeks) was prescribed, resulting in scar formation. The patient has remained free of relapse for one year to date, since the end of treatment. Localized cutaneous cryptococcosis is not a commonly used disease name overseas. However, 36 cases of this disease have been reported in Japan (since in 1968). We herein report a new case with localized cutaneous cryptococcosis and summarize previously reported cases in Japan.
Disseminated cryptococcosis is rare but can often become severe with a poor outcome. Given recent reports that matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analyser is useful for Cryptococcus species identification, it was applied retrospectively to past cases of disseminated cryptococcosis at our hospital over the past 10 years, and their clinical courses were reviewed. For each case, the retained Cryptococcus spp. were used for identification using both MALDI-TOF MS and genetic sequencing, as well as for drug susceptibility testing. A total of eight cases were found. Cryptococcus spp. were found in cerebrospinal fluid in 3 cases and blood in 5 cases; anti-HIV antibody was either negative or untested. MALDI-TOF MS identified Cryptococcus neoformans as the pathogen in all 8 cases, but genetic testing identified one of these as Cryptococcus curvatus. The outcome was death within 30 days in 5 of the total 8 cases and in 2 of the 3 cases in which C. neoformans was detected in the cerebrospinal fluid, despite regimens and dosages that followed IDSA Guidelines in all 3 cases. Drug susceptibility testing showed no drug resistance that would have affected the therapy. In conclusion, the outcomes were very poor in these drug-susceptible cases, despite treatment in full accordance with standard guidelines. This study confirmed the need to develop newer therapies as well as the high capability of MALDI-TOF MS for the identification of C. neoformans. Genetic testing, however, may be necessary if non-neoformans Cryptococcus is suspected.
Sporotrichosis is a fungal infection caused by the Sporothrix species, which have distinct virulence profiles and geographic distributions. We performed a phylogenetic study in strains morphologically identified as Sporothrix schenckii from clinical specimens in Japan, which were preserved at the Medical Mycology Research Center, Chiba University. In addition, we examined the in vitro antifungal susceptibility and growth rate to evaluate their physiological features. Three hundred strains were examined using sequence analysis of the partial calmodulin gene, or polymerase chain reaction（PCR）method using newly designed species-specific primers; 291 strains were Sporothrix globosa and 9 strains were S. schenckii sensu stricto (in narrow sense, s. s.). S. globosa strains were further clustered into two subclades, and S. schenckii s. s. strains were divided into three subclades. In 38 strains of S. globosa for which antifungal profiles were determined, 4 strains (11%) showed high minimal inhibitory concentration (MIC) value for itraconazole. All tested strains of S. schenckii s. s. and S. globosa showed low sensitivity for amphotericin B. These antifungals are used for treatment of sporotrichosis when infection is severe. S. schenckii s. s. grew better than S. globosa; wherein S. globosa showed restricted growth at 35℃ and did not grow at 37℃. Our molecular data showed that S. globosa is the main causal agent of sporotrichosis in Japan. It is important to determine the antifungal profiles of each case, in addition to accurate species-level identification, to strategize the therapy for sporotrichosis.
A 41-year-old man visited our dermatology clinic because an eruption, which was resistant to steroid ointment treatment, had appeared on his right forearm. An oval, soybean-sized erythematous infiltrated lesion with scales and crusts was located in the central part of the extensor surface of the right forearm and showed partial erosion with attached yellow crusts. The lesion had an impetigo-like appearance. Fungal elements were confirmed from the scales by KOH examination and the fungus was identified as Trichophyton tonsurans by fungal culture and molecular method. Clinical features of T. tonsurans infection vary, wherein some patients have strong inflammatory manifestations, while others remain as asymptomatic carriers. Especially at the early stage of the infection, diagnosis is difficult because it is often misdiagnosed as eczema. We report a case of T. tonsurans infection that had impetigo-like appearance. We also studied the mechanism of the disease.
Topical or systemic antifungal therapy was administered to patients diagnosed with Malassezia folliculitis during the 5-year period between March 2007 and October 2013. The diagnosis of Malassezia folliculitis was established on the basis of characteristic clinical features and direct microscopic findings (10 or more yeast-like fungi per follicle). Treatment consisted of topical application of 2% ketoconazole cream or 100 mg oral itraconazole based on symptom severity and patients’ preferences. Treatment was given until papules flattened, and flat papules were examined to determine whether the patient’s clinical condition had “improved” and the treatment had been “effective”. The subjects were 44 patients (35 men, 9 women), with a mean disease period of 25±15 days. In regard to the lesion site, the frontal portion of the chest was the most common, accounting for 60% of all patients. The mean period required for improvement was 27±16 days in 37 patients receiving the topical antifungal agent and 14±4 days in the 7 patients receiving the systemic antifungal agent. The results were “improved” and the treatment was “effective” in all patients. Neither treatment resulted in any adverse reactions. Although administration of oral agents has been recommended for the treatment of Malassezia folliculitis, this study revealed that beneficial results are safely obtained with topical antifungal therapy alone, similar to those of systemic antifungal agents.