Isolate resistance of Blastocystis hominis to metronidazole.
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Isolates of Blastocystis hominis from infected immigrant workers from Indonesia, Bangladesh and infected individuals from Singapore and Malaysia were assessed for growth pattern and degree of resistance to different concentrations of metronidazole. Viability of the cells was assessed using eosin-brillian cresyl blue which stained viable cells green and nonviable cells red. The Bangladeshi and Singaporean isolates were nonviable even at the lowest concentration of 0.01 mg/ml, whereas 40% of the initial inoculum of parasites from the Indonesian isolate at day one were still viable in cultures with 1.0 mg/ml metronidazole. The study shows that isolates of B. hominis of different geographical origin have different levels of resistance to metronidazole. The search for more effective drugs to eliminate th parasite appears inevitable, especially since surviving parasites from metronidazole cultures show greater ability to multiply in subcultures than controls. (+info)
Intestinal blockage by carcinoma and Blastocystis hominis infection.
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We detected heavy infections of Blastocystis hominis in four individuals with intestinal obstruction due to cancerous growths. After surgery, the infections spontaneously resolved, without specific chemotherapy. It appears that the B. hominis infection was coincidental and not related to the neoplastic growth. We suggest that intestinal obstruction and concomitant stool retention, plus hemorrhage from cancerous lesions, may have permitted the more abundant growth of B. hominis. This is the first report of a possible relationship between intestinal obstruction and a concomitant B. hominis infection. (+info)
Genomic analysis of Blastocystis hominis strains isolated from two long-term health care facilities.
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The genotype Blastocystis hominis is highly polymorphic. Therefore, a genetic marker would be a powerful tool for the identification or classification of B. hominis subtypes and could be used as a means to resolve the transmission route or origin of the parasite. To this end, 32 B. hominis isolates were collected from patients and/or staff members of two long-term health care facilities (facilities A and B), and these organisms were subjected to genotype analysis based on diagnostic PCR primers and restriction fragment length polymorphism (RFLP) of small subunit rRNA gene (rDNA). Based on PCR amplification using diagnostic primers which were developed from randomly amplified polymorphic DNA analysis of known strains of B. hominis, the 32 isolates of B. hominis were classified into three different subtypes. Thirty isolates, including twenty-four that were isolated from patients and a staff member, from facility A and all isolates isolated from six patients from facility B showed the same genotype. Two of six patients of facility B had been transferred from facility A, and these two patients also had the same-genotype B. hominis that corresponded to 24 isolates from facility A. This genotype strain may have been transmitted by these two patients from facility A to facility B, suggesting human-to-human transmission. In contrast, 2 of 26 isolates from facility A showed distinct genotypes, suggesting that the colonization by these two isolates is attributable to another infectious route. These different subtypes were subjected to RFLP analysis, and the RFLP profiles were correlated with the results obtained by diagnostic PCR primers. This study presents the first molecular evidence of possible human-to-human B. hominis infection between and/or among two small communities. (+info)
Clinical significance and frequency of Blastocystis hominis in Turkish patients with hematological malignancy.
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The effect of Blastocystis hominis (B. hominis) in both immunocompetent and immunocompromised subjects has been the subject of debate in recent years, mostly in response to its unknown pathogenicity and frequency of occurrence. We performed a non-randomised, open labelled, single institute study in our hospital in order to investigate the clinical significance and frequency of B. hominis in patients suffering from hematological malignancy (HM) who displayed symptoms of gastrointestinal diseases during the period of chemotherapy-induced neutropenia. The presence and potential role of other intestinal inclusive of parasites were also studied. At least 3 stool samples from each of 206 HM patients with gastrointestinal complaints (the HM group) were studied. These were compared with stool samples from a control group of 200 patients without HM who were also suffering from gastrointestinal complaints. Samples were studied with saline-lugol, formalin-ether, and trichome staining methods. Groups were comparable in terms of gender, age and type of gastrointestinal complaints. In the HM group, the most common parasite was B. hominis. In this group, 23 patients (13%) had B. hominis, while in the control group only 2 patients (1%) had B. hominis. This difference was statistically significant (P < 0.05). Symptoms were non-specific for B. hominis or other parasites in the HM group. The predominant symptoms in both groups were abdominal pain (87-89.5%), diarrhea (70-89.5%), and flatulence (74-68.4%). Although all patients with HM were symptom-free at the end of treatment with oral metranidazol (1,500 mg per day for 10 days) 2 patients with HM had positive stool samples containing an insignificant number of parasites (< 5 cells per field). In conclusion, it appears that B. hominis is not rare and should be considered in patients with HM who have gastrointestinal complaints while being treated with chemotherapy. Furthermore, metranidazol appears to be effective in treating B. hominis infection. (+info)
Ribodemes of Blastocystis hominis isolated in Japan.
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To determine if genetic diversity of Blastocystis hominis exists in Japan, we monitored 64 B. hominis-infected people: 39 asymptomatic people whose infections were detected during routine medical check-ups (32 Japanese and 7 non-Japanese) and 25 patients with gastrointestinal symptoms who visited the outpatient clinics of St. Luke's International Hospital (19 Japanese and 6 non-Japanese). We detected 6 known and 2 new riboprint patterns in isolates from the infected people. There were no differences in the distribution of ribodemes between isolates from Japanese and non-Japanese people, similar to that in other countries. However, we noted a possible relationship between ribodeme type and pathogenicity. The results suggest that ribodemes I, III, and VI may be responsible for gastrointestinal symptoms. (+info)
Epidemiological survey of Blastocystis hominis in Huainan City, Anhui Province, China.
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AIM: To provide scientific evidence for prevention and controlling of blastocystosis, the infection of Blastocystis homonis and to study its clinical significance in Huainan City, Anhui Province, China. METHODS: Blastocystis homonis in fresh stools taken from 100 infants, 100 pupils, 100 middle school students and 403 patients with diarrhea was smeared and detected with method of iodine staining and hematoxylin staining. After preliminary direct microscopy, the shape and size of Blastocystis homonis were observed with high power lens. The cellular immune function of the patients with blastocystosis was detected with biotin-streptavidin (BSA). RESULTS: The positive rates of Blastocystis homonis in fresh stools taken from the infants, pupils, middle school students and the patients with diarrhea, were 1.0 % (1/100), 1.0 % (1/100), 0 % (0/100) and 5.96 % (24/403) respectively. Furthermore, the positive rates of Blastocystis homonis in the stool samples taken from the patients with mild diarrhea, intermediate diarrhea, severe diarrhea and obstinate diarrhea were 6.03 % (14/232), 2.25 % (2/89), 0 % (0/17) and 12.31 % (8/65) respectively. The positive rates of Blastocystis homonis in fresh stools of male and female patients with diarrhea were 7.52 % (17/226) and 3.95 % (7/177) respectively, and those of patients in urban and rural areas were 4.56 % (11/241) and 8.02 % (13/162) respectively. There was no significant difference between them (P>0.05). The positive rates of CD(3)(+), CD(4)(+), CD(8)(+) in serum of Blastocystis homonis-positive and-negative individuals were 0.64+/-0.06, 0.44+/-0.06, 0.28+/-0.04 and 0.60+/-0.05, 0.40+/-0.05 and 0.30+/-0.05 respectively, and the ratio of CD(4)(+)/CD(8)(+) of the two groups were 1.53+/-0.34 and 1.27+/-0.22. There was significant difference between the two groups (P<0.05, P<0.01). CONCLUSION: The prevalence of Blastocystis hominis as an enteric pathogen in human seems not to be associated with gender and living environment, and that Blastocystis hominis is more common in stool samples of the patients with diarrhea, especially with chronic diarrhea or obstinate diarrhea. When patients with diarrhea infected by Blastocystis hominis, their cellular immune function decreases, which make it more difficult to be cured. (+info)
Clinical characteristics and endoscopic findings associated with Blastocystis hominis in healthy adults.
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Ninety-nine individuals with stools positive for Blastocystis hominis but negative for other parasites were identified from medical records of healthy adults who had received a physical examination at Taipei Veterans General Hospital from November 2000 to October 2002. The medical records of these 99 positive cases and 193 randomly selected controls, matched for age, sex, and date of examination, were retrospectively reviewed. The pathogenicity of B. hominis could not be demonstrated due to a lack of association with the development of gastrointestinal symptoms or pathologic findings on endoscopic examination. Multivariate analyses revealed that chronic hepatitis B infection was a predisposing condition to the acquisition of B. hominis (odd ratio = 2.848, 95% confidence interval = 1.299-6.242, P = 0.009), and concentration of urate was significantly lower in B. hominis-positive individuals (mean +/- SD = 361.64 +/- 87.44 versus 392.57 +/- 93.38 micromol/L; P = 0.009). Among the 64 individuals who underwent gastric biopsy, Helicobacter pylori was found more frequently in the individuals harboring B. hominis (19 of 26 versus 15 of 38; P = 0.017). (+info)
Irritable bowel syndrome: in search of an etiology: role of Blastocystis hominis.
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This study was designed to examine stool specimens of irritable bowel syndrome (IBS) patients for Blastocystis hominis, a common intestinal parasite. One hundred fifty patients were enrolled, 95 IBS cases and 55 controls. These patients provided a medical history, and underwent physical and laboratory evaluations that included stool microscopy and culture for B. hominis and colonoscopy. The 95 cases (51 males and 44 females) had a mean +/- SD age of 37.8 +/- 13.2 years. Stool microscopy was positive for B. hominis in 32% (30 of 95) of the cases and 7% (4 of 55) of the controls (P = 0.001). Stool culture was positive in 46% (44 of 95) of the cases and 7% (4 of 55) of the controls (P < 0.001). Stool culture for B. hominis in IBS was more sensitive than microscopy (P < 0.001). Blastocystis hominis was frequently demonstrated in the stool samples of IBS patients; however, its significance in IBS still needs to be investigated. Stool culture has a higher positive yield for B. hominis than stool microscopy. (+info)