Mehmet Tanyuksel

Laboratory Diagnosis of Amebiasis

SUMMARY The detection of Entamoeba histolytica, the causative agent of amebiasis, is an important goal of the clinical microbiology laboratory. To assess the scope of E. histolytica infection, it is necessary to utilize accurate diagnostic tools. As more is discovered about the molecular and cell biology of E. histolytica, there is great potential for further understanding the pathogenesis of amebiasis. Molecular biology-based diagnosis may become the technique of choice in the future because establishment of these protozoa in culture is still not a routine clinical laboratory process. In all cases, combination of serologic tests with detection of the parasite (by antigen detection or PCR) offers the best approach to diagnosis, while PCR techniques remain impractical in many developing country settings. The detection of amebic markers in serum in patients with amebic colitis and liver abscess appears promising but is still only a research tool. On the other hand, stool antigen detection tests offer a practical, sensitive, and specific way for the clinical laboratory to detect intestinal E. histolytica. All the current tests suffer from the fact that the antigens detected are denatured by fixation of the stool specimen, limiting testing to fresh or frozen samples.

Blastocystis subtypes in irritable bowel syndrome and inflammatory bowel disease in Ankara, Turkey

Blastocystis infection has been reported to be associated with irritable bowel syndrome (IBS), inflammatory bowel disease (IBD) and chronic diarrhoea. The availability of data on the subtypes of Blastocystis found in these patient groups would be of interest in understanding the significance of Blastocystis infection in chronic illness. In this study, we identify Blastocystis subtypes found in patients presenting with IBS, IBD, chronic diarrhoea and asymptomatic patients in Ankara, Turkey. Blastocystis was detected in 11 symptomatic patients by microscopy and 19 by stool culture. Stool culture was more sensitive than microscopy in identifying Blastocystis. Using standard nomenclature adopted in 2007, Blastocystis sp. subtype 3 was the most common in all groups, followed by Blastocystis sp. subtype 2. Identical subtypes of Blastocystis are found in patients with IBS, IBD and chronic diarrhoea. These particular subtypes show low host specificity and are carried by humans and some farm animals. The subtypes of Blastocystis that are commonly found in rodents and certain wild birds were not found in these patients. We suggest a model in which the severity of enteric protozoan infection may be mediated by host factors.

Saccharomyces boulardii and infection due to Giardia lamblia

Therapy with metronidazole is the recommended option in giardiasis. However, some clinical trial reports suggest the appearance of drug resistance to explain therapeutic failure. Several investigations have been carried out on the effect of probiotic microorganisms for preventing or treating gastrointestinal diseases, but little is known about their efficacy against protozoal infections. The principal objective of our study was to evaluate the efficacy of Saccharomyces boulardii against Giardia lamblia infections. A double-blind, placebo-controlled study was carried out on adult patients with giardiasis. Group 1 (30 patients) included metronidazole 750 mg 3 times daily along with S. boulardii capsules (250 mg b.i.d. orally) for 10 d while group 2 (35 patients) was treated with metronidazole 750 mg 3 times daily and with empty capsules as placebo for 10 d. Patients were re-examined at 2 and 4 weeks after treatment, and stool examinations were performed. At week 2, G. lamblia cysts were detected in 6 cases (17.1%) of group 2 and none in group 1. At the end of the fourth week, presence of the cysts continued in the same 6 cases in group 2 (control group). These findings indicated that S. boulardii may be effective in treating giardiasis when combined with metronidazole therapy.

Entamoeba histolytica: sequence conservation of the Gal/GalNAc lectin from clinical isolates.

The Gal/GalNAc lectin gene of Entamoeba histolytica is a major amebic virulence protein responsible for interaction with host tissues. We investigated sequence differences in the Gal/GalNAc lectin heavy subunit in three isolates from Bangladesh and one isolate from Georgia, each of which was determined to be genetically distinct by SREHP AluI digestion. Interestingly, we observed only slight genetic diversity in the lectin gene as compared with the HM1:IMSS laboratory strain, originally a clinical isolate from Mexico. Genetic conservation of the Gal/GalNAc lectin between isolates may reflect that the lectin is under strong functional selection or possibly, that E. histolytica is a clonal population. Sequence conservation of the lectin indicates that immune responses against it should be cross-protective.

The scolicidal effects of honey

Echinococcosis is a zoonosis that is caused by adult or larval tapeworms belonging to the genusEchinococcus. Until now, no studies have sought to determine the scolicidal effects of honey. Therefore, the present study was undertaken to explore the scolicidal effects of honey in different concentrations for various exposure times. Tubes that contained at least 500 protoscolices were supplemented with 1 %, 5%, 10%, 25%, and 50% concentrations of honey. Tubes were maintained at room temperature for 0.5, 1, 2, 3, 4, 5, and 10 min. At the end of the incubation times, the viability of protoscolices was assessed through a trypan blue exclusion test. The effective dose of honey was applied intraperitoneally to determine whether it caused an anaphylactic reaction or hyperglycemia. Honey concentrations of 10% or greater killed all protoscolices. The scolicidal effects of honey began at the end of the third minute. Honey did not cause adverse effects when applied intraperitoneally. In this study, an investigation of the scolicidal effects of honey showed that it is highly effective at a 10% concentration. On the basis of in vivo study results, the investigators concluded that honey is a potent scolicidal agent.

The prevalence of intestinal parasites in the province of Izmir, Turkey

Stool samples of a total of 2,047 people in Izmir province were examined by wet mount, formalin ethyl acetate concentration, and trichrome staining methods with an aim to reveal the prevalence of intestinal parasites in Izmir together with related personal and environmental risk factors. Geographical mapping showing the density and variation of the species of intestinal parasites in Izmir was done after all maps were scaled, and the coordinates were determined with GeoMedia5.0®. The prevalence of the intestinal parasites was found to be 25.6 % in Izmir, with a variation between the districts. Blastocystis hominis was the leading parasite, and the prevalence of parasites was higher in children compared to adults; however, the difference was statistically insignificant. There was also no significant difference between the parasite prevalence and sex, marital status, education, income, frequent eating outside, and habitual raw meat eating. Significant differences were found between the parasite prevalence and crowded families, early immigrants, individuals with no social security, and people living in close contact with their livestock. The parasites were found to be less common among individuals who had been drinking bottled water and living in a house with a sewage system. The results demonstrated a correlation between the intestinal parasites and environmental conditions in our study group. We further plan to expand the study group to cover all regions of Turkey.

Maggot Debridement Therapy in the Treatment of Chronic Wounds in a Military Hospital Setup in Turkey

Background: The medicinal use of maggots for the biological debridement of chronic wounds is increasing around the world, due to its efficacy, safety and simplicity. Thousands of patients have been treated in private and governmental hospitals during the last 10 years. Objective: To examine the efficacy of maggot debridement therapy (MDT) in the debridement of chronic wounds in a militaryhospital. Methods: MDT was applied for 1–9 days to 7 male and 4 female soldiers or their family members (21–72 years old) with chronic wounds. Results: Complete debridement was achieved in 10 out of 11 patients, while in 1 patient the wound could be cleaned only partially. A remarkable reduction in the odor emanating from the wound and notable granulation were observed in all debrided wounds. Increased pain was observed in 1 patient with a venous stasis ulcer. Conclusion: We believe that MDT is a rapid and effective method for the debridement of chronic wounds in a military environment especially in times of war in developing countries.

Prevalence of Cryptosporidium sp. in Patients with Neoplasia and Diarrhea

The prevalence of Cryptosporidium sp. was investigated in fecal specimens from 106 patients with neoplasia and diarrhea (74 females, 32 males) by using Ziehl-Neelsen and Giemsa stains. Oocystic forms of Cryptosporidium sp. were found in 18 (17%) of these patients. No oocystic form of Cryptosporidium sp. was detected in the control group of 60 patients with neoplasia (37 females, 23 males) but without diarrhea. The frequent findings of Cryptosporidium sp. in patients with neoplasia and diarrhea who are undergoing chemotherapy indicates that a search for this organism is justified.

Evaluation on scolicidal efficacy of propolis.

Background: Propolis is a resinous material collected by bees from various plants. It has antimicrobial, antioxidative, immunostimulative, and regenerative properties. We determined the scolicidal effect of propolis in different concentrations and various exposure times. Materials and Methods: Tubes containing Echinococcus granulosus protoscoleces were supplementedwith different concentrations of ethyl alcohol extract of propolis. At the end of the incubation times, viabilityof protoscoleces was assessed by trypan blue exclusion test. We also applied 5 ml of 1 µg/ml propolis intraperitoneally for determination of side effects and mortality rates. Results: We determined that 1 µg/ml concentration of propolis killed all of the protoscoleces at the end of the 3rd minute. In the in vivo part of the study, intraperitoneal application of propolis did not cause any side effects or mortality. Conclusion: We concluded that this natural agent can be used as a potent scolicidal agent after studies which will determine in vivo efficacy and the effects on liver and biliary tree when injected directly into the common bile duct.

Investigation of Entamoeba histolytica and Mycobacterium spp. in biopsy specimens of patients with inflammatory bowel disease in Turkey

Intestinal amebiasis and gastrointestinal tuberculosis can mimic inflammatory bowel disease and its exacerbations clinically, pathologically, radiologically and endoscopically. In the existence of IBD and/or either one of these two pathogens, early identification and prompt treatment can improve the clinical course of the patients. The aim of this study was to investigate the presence of Entamoeba histolytica and/or Mycobacterium spp. in the first diagnostic biopsy specimens of prediagnosed IBD patients in a tertiary education hospital in Ankara, Turkey. As the differentiation of pathologic Entamoeba histolytica must be based on isoenzymatic, immunologic or molecular analysis and PCR is a rapid and reliable method for the identification of Mycobacterium spp., we investigated the presence of these pathogens in the biopsy specimens of 20 patients who were suspected to have IBD and nine controls, by using PCR-based detection methods. All of them were histopathologically diagnosed as Crohn’s disease and none of the specimens contained these two pathogens. We thought that the low prevalence of both infections in Crohn’s disease patients may have caused our negative findings and loss of pathogens could have lowered the sensitivity. Further studies with larger number of patients are needed to determine the misdiagnosis rate and coexistence of these three diseases.