Subgenus classification of Acanthamoeba remains uncertain. Twenty-three reference strains of Acanthamoeba including 18 (neo)type-strains were subjected for classification at the subgenus level by riboprinting. PCR/RFLP analysis of 18S rRNA gene (rDNA). On the dendrogram reconstructed on the basis of riboprint analyses, two type-strains (A. astronyxis and A. tubiashi) of morphological group 1 diverged early from the other strains and were quite distinct from each other. Four type-strains of morphological group 3, A. culbertsoni, A. palestinensis, A. healyi were considered taxonomically valid, but A. pustulosa was regarded as an invalid synonym of A. palestinensis. Strains of morphological group 2 were classified into 6 subgroups. Among them, A. griffini which has an intron in its 18S rDNA was the most divergent from the remaining strains. Acanthamoeba castellanii Castellani, A. quina Vil3, A. lugdunensis L3a, A. polyphaga Jones, A. triangularis SH621, and A. castellanii Ma strains belonged to a subgroup, A. castellanii complex. However, A. quina and A. lugdunensis were regarded as synonyms of A. castellanii. The Chang strain could be regarded as A. hatchetti. Acanthamoeba mauritaniensis, A. divionensis, A. paradivionensis could be considered as synonyms of A. rhysodes. Neff strain was regarded as A. polyphaga rather than as A. castellanii. It is likely that riboprinting can be applied for rapid identification of Acanthamoeba isolated from the clinical specimens and environments.

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Strongyloides stercoralis can cause systemic infection, termed strongyloidiasis, and gastrointestinal ulcer disease in immunocompromised patients. However, to our knowledge, there are no reported cases of comorbid gastric adenocarcinoma and S. stercoralis infection. Here, we report a case of an 81-year-old Korean man who presented with S. stercoralis infection coexisting with early gastric adenocarcinoma (T1aN0M0). S. stercoralis eggs, rhabditiform larvae, and adult females were observed in normal gastric and duodenal crypts. They were also observed in atypical glands representative of adenocarcinoma and adenoma. Preliminary laboratory tests revealed mild neutrophilic and eosinophilic leukocytosis. A routine stool test failed to detect rhabditiform larvae in the patient’s fecal sample; however, S. stercoralis was identified by PCR amplification and 18S rRNA sequencing using genomic DNA extracted from formalin-fixed paraffin-embedded tissues. Postoperatively, the patient had a persistent fever and was treated with albendazole for 7 days, which alleviated the fever. The patient was followed-up by monitoring and laboratory testing for 4 months postoperatively, and no abnormalities were observed thus far. The fact that S. stercoralis infection may be fatal in immunocompromised patients should be kept in mind when assessing high-risk patients.

Trichomonas vaginalis, a causative agent of trichomoniasis, may trigger symptomatic or asymptomatic nongonococcal urethritis and chronic prostatitis in men. Despite the availability of highly sensitive diagnostic tests, such as nucleic acid amplification tests, including PCR, few prospective studies present data on male T. vaginalis infection in South Korea. In the present study, the prevalence of T. vaginalis and associated clinical conditions were evaluated in 201 male patients from a primary care urology clinic in South Korea. The prevalence of T. vaginalis infection in our cohort was 4% (8/201) by PCR. T. vaginalis infection was common in men older than 40 years (median age, 52 years). Among the 8 Trichomonas-positive patients, 87.5% (7/8) had prostatic diseases, such as prostatitis and benign prostatic hyperplasia, and 25.0% (2/8) and 12.5% (1/8) were coinfected with Chlamydia trachomatis and Mycoplasma genitalium, respectively. Our results suggest that T. vaginalis infection is not rare in men attending primary care urology clinics in South Korea, especially in those older than 40 years, in whom it may explain the presence of prostatic disease. The possibility of T. vaginalis infection should be routinely considered in older male patients with prostatic diseases in South Korea.

We applied ribosomal RNA gene (rDNA) polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to identify Acanthamoeba isolates from contact lens paraphernalia, and characterized these on the basis of mitochondrial DNA (mtDNA) RFLP and isoenzyme analysis. The 22 Acanthamoeba strains used as reference strains were obtained from the American Type Culture Collection. Twenty-eight isolates were classified into six ribogroups, as follows: Acanthamoeba ribogroup (AcRG) 1 consisted of 18 isolates; AcRG 2, of three, AcRG 3, of three; AcRG 4, of two; AcRG 5, of one, and AcRG 6, of one. AcRG 1, which was the most frequently isolated type, was identified as A. lugdunensis, and AcRG 2 as A. hatchetti. AcRG 4 was identified as A. triangularis, while AcRG 3 and AcRG 5 were closely related to A. triangularis. AcRG 6 was identified as A. castellanii. The mtDNA RFLP patterns and zymograms for five isoenzymes of the isolates belonging to a ribogroup were identical to one another. The mtDNA digestion phenotype and zymogram for acid phosphatase (AcP) of AcRG 1 were identical to those of A. lugdunensis L3a and KA/E2, the type strain and corneal isolates from a Korean keratitis patient, respectively. The mtDNA digestion phenotype and zymogram for AcP of AcRG 6 were identical to those of A. castellanii Castellani and KA/E3, the type strain and another corneal isolate found in Korea, respectively. The mtDNA RFLP and zymogram for AcP of AcRG 2 were very similar to those of A. hatchetti BH-2 and Chang, respectively the type strain and a pathogen. The mtDNA RFLP and zymogram for AcP of AcRG 4 were similar to those of A. triangularis SH621, the type strain. The mtDNA RFLP patterns of AcRG 3 and 5 were unique. These results showed that the riboprints, mtDNA RFLP and zymograms of 22 of 28 Acanthamoeba isolates were the same as or very similar to those of the clinical isolates, which can probably be regarded as keratopathogens. More attention should be paid to the prevention of contamination by Acanthamoeba and to the disinfection of contact lens paraphernalia.