Simple Smear Research Articles

Laboratory diagnosis of Blastocystis spp. in diarrheic patients.

Background:Many laboratories currently diagnose Blastocystis spp. infections by looking for the presence of vacuolar forms in faeces and the amoeboid form in diarrheal stools.Objectives:To investigate the best direct method in diagnosis of Blastocystis spp. and to study different morphological forms of the parasite.Materials and Methods:The study was carried out on one thousand and two hundred diarrheic stool samples. All samples were examined using direct smear, iodine stained smear, formalin-ether concentration techniques, trichrome stained smear and in vitro cultivation using Jones' medium.Results:Using direct smear, Blastocystis spp was detected in 42 cases (3.5%) with a sensitivity (28.4%) and specificity (100%). Iodine stained smear detected 72 positive cases (6%) with a sensitivity (48.7%), specificity (100%). Formol ether concentration technique detected 120 positive cases (10%) with a sensitivity (81.1%) and specificity (100%). Trichrome stained smear detected 148 positive cases (12.3%). In vitro cultivation using Joni's medium detected 274 positive cases (22.8%) which was the highest number among all different diagnostic methods with a sensitivity (100%) ,specificity (88%), PPV (54.1%) and NPV (100%). It was found that, 49 blastocystosis cases had mixed infection with other intestinal parasites. Giardia lamblia was the most frequently associated parasite with Blastocystis spp.Conclusion:In vitro cultivation is more sensitive in detection of B. hominis than simple smear and concentration technique. Blastocystis spp. vacuolar form was the most common form that was found by all methods used in this study G. lamblia was the most frequent parasite associated with Blastocystis spp .

Can HPV Testing Be Used as a First-line Screening Test for Cervical Cancer Prevention? Three-year Cumulative Risk of CIN2+ In Women Aged 30 Years and Older Screened by Pap and HPV Co-testing

Introduction: Over time, cervical screening has evolved from a simple glass-slide smear to a sophisticated test involving liquid-based processing, automated screening, and molecular human papillomavirus (HPV) testing. Recent emphasis on molecular testing seeks to identify HPV strains considered “high-risk” for carcinogenesis, with HPV 16 & 18 being the main focus of research and clinical practice. But is molecular testing more effective and efficient than morphologic testing for cervical screening? Does current data on HPV hold true across all populations? As a public health laboratory serving high-risk, underserved populations, these remain important considerations for our practice. Materials and Methods: Correlation of Pap and HPV results was performed via retrospective review, focusing on Pap cases with high-grade diagnoses and an associated HPV test using the cobas 4800 HPV platform from Roche Diagnostics. HPV results included HPV 16, HPV 18, HPV Other High-Risk, a combination of two or more groups, or HPV Not Detected. The subject population consisted mostly of young women within 200% or less of the poverty line. Results: Of 2,818 cytology test cases reviewed from July 2013-March 2014, 74 were diagnosed as high-grade. HPV was not detected in 10 (13.51%) of these cases. Of the 64 positive HPV tests, 25 (39.06%) fell in the Other High-Risk category. In total, 35 (52.57%) of the high-grade Pap cases were not HPV 16/18 positive. Conclusions: With recent changes to cervical screening practices and guidelines, namely the emphasis on molecular HPV testing, the results of this review are concerning. How will these changes in screening affect our bottom line, both financially and prognostically? Is our patient population substantially different from those used to develop popular testing algorithms? As we move forward with evolution of cervical screening practices, it will be important to explore these questions for the continued quality and integrity of women’s health services.

Picturing Cervical Cancer

The Pap smear has been used to test women for cervical cancer since its invention in 1928. With a simple swipe and smear, doctors have been able to use microscopic observation to detect cancerous activity. Because cervical cancer is one of the most preventable forms of cancer, the Pap smear revolutionized how we deal with the disease. Yet, worldwide, 275 000 women (1) still die from cervical cancer each year. That's because although the Pap is an efficient test, it requires elements such as facilities, follow-up visits, and trained cytology technicians, making it difficult to use in low- to middle-income neighborhoods. In these areas, some of which are right here in the US, visual inspection with acetic acid (VIA)3 has become the norm in cervical cancer screening. In this procedure, the cervix is washed with acetic acid, and a physician scans the cervix with his or her own eyes, without any magnification, looking for white spots, which might possibly be a clump of cancerous cells. The problem with VIA, however, is that it can offer an often imprecise and delayed picture. If a physician can actually see the cancer on the surface of the cervix, that would indicate the tumor has become large enough to burst through the skin's surface, from the deeper tissues below, meaning it is very advanced. And, white doesn't always mean cancer. So, although VIA has reduced cervical cancer mortality rates by some 30% (2), it has a false-positive rate that can hover near 83%. What would be ideal, says David Levitz, cofounder of MobileOCT, a technology company, is a different type of screening test that can enhance a physician's vision beyond 20/20. MobileOCT is working on just such an optical cervical cancer screening technology, optical coherence tomography (OCT). The team plans to start a …

Intestinal parasitic infections: high prevalence of Giardia intestinalis in children living in an orphanage compared with hill-tribe children as detected by microscopy and ELISA

Background: Data regarding intestinal parasitic infections in preschool-aged children (less than 6 years old)living in an orphanage and remote mountainous areas are very limited. Objectives: We surveyed infections in orphans and hill-tribe children. Materials and Methods: They were studied in 2008 by stool examination (simple smear and concentration), Scotch-tape and culture (Boeck and Drbohlav's Lock-Egg-Serum medium) techniques. The Giardia coproantigen ELISA was also performed. The risk correlation between unusual stool types and giardiasis by univariate analysis was tested. Results: The overall infection rates in 137 orphans and in 145 hill-tribe children were 58.4% and 77.9%, respectively.Giardia intestinalis had the highest prevalence in orphans (with microscopy 28.5%, with copro-antigen ELISA31.4%). Other pathogens included Blastocystis hominis (23.4%), Enterobius vermicularis (9.5%), andhookworm (0.7%), whereas the nonpathogens were Trichomonas hominis (19.0%), Entamoeba coli (11.7%), and Endolimax nana (2.2%). Ascaris lumbricoides had the highest prevalence (62.1%) in hill-tribe children, whileGiardia intestinalis showed 7.6% with microscopy and 9.0% by ELISA. The other pathogens were E. vermicularis(25.5%), Trichuris trichiura (10.3%), B. hominis (2.8%), hookworm (1.4%), Sarcocystis hominis (1.4%) andE. histolytica (0.7%), whereas the nonpathogenic organisms were E. coli (19.3%), and E. nana (0.7%). Giardiasisstools from orphans had significantly greater cyst density than those from the hill-tribe children. The coproantigenELISA for giardiasis demonstrated 91.4% specificity, 72.0% sensitivity, 64.3% positive predictive value,and 93.8% negative predictive value, respectively. By univariate analysis, a loose (mushy) stool type was 2.43times likely to have Giardia cysts. Conclusion: In large-scale epidemiological studies, a Giardia ELISA might be a useful aid for diagnosis, becauseconventional microscopy is time-consuming and relies on the expertise of the microscopist. Keywords: ELISA, Giardia intestinalis, hill-tribe children, intestinal parasite, microscopy, orphanage children,preschool-aged children

P25 Sensitivity of the Xpert® MTB/RIF assay in bronchoalveolar lavage samples in a North West London Hospital: a useful adjunct to current diagnostic modalities

Introduction and ObjectivesThe Gene Xpert® MTB/RIF test has been validated in sputum samples, facilitating rapid mycobacterium tuberculosis (MTB) diagnosis with improved sensitivity compared to smear alone. Its utility in bronchoalveolar...

Incidence and risk factors of Blastocystis infection in an orphanage in Bangkok, Thailand

BackgroundBlastocystis sp. is one of the most common intestinal protozoa in humans. Unlike other intestinal parasitic infections such as giardiasis and cryptosporidiosis, the epidemiology of blastocystosis in children who live in crowded settings such as day-care centers and orphanages has been rarely explored.MethodsA retrospective cohort study was conducted to evaluate incidence and risk factors of Blastocystis infection in an orphanage every two consecutive months during April 2003 to April 2004, in Bangkok, Thailand. Blastocystis sp. was identified using direct simple smear, and in vitro cultivation in Jones' medium.ResultsThe incidence rate was 1.8/100 person-months and the independent risk factors associated with Blastocystis infection were age, nutritional status and orphans living in the room where their childcare workers were infected.ConclusionsPerson-to-person transmission was most likely to occur either from orphans to childcare workers or from childcare workers to orphans living in the same room. Universal precautions such as regular hand washing and careful handling of fecally contaminated materials are indicated.

Intestinal helminths in a population of children from the Kashmir valley, India

In any geographical area, surveys of the prevalence of intestinal helminths are necessary to suggest appropriate control measures. The aim of this study was to determine the prevalence of intestinal helminth infections in children of the Kashmir valley and to identify the risk factors. Stool samples were collected from 2256 children from rural as well as urban areas of the Kashmir valley. The samples were examined by simple smear and zinc sulphate concentration methods. Intensity of the infection was quantified by Stoll's egg-counting technique. Infection by at least one intestinal helminth was found in 71.18% of the sampled population. The prevalence of Ascaris lumbricoides was highest (68.30%), followed by Trichuris trichiura (27.92%), Enterobius vermicularis (12.67%) and Taenia saginata (4.60%). Light (57.1%) to moderate (42.8%) intensity of infection was observed for A. lumbricoides, while the majority of the infected children (92.3%) harboured a light intensity of infection for T. trichiura. The age group, rural or urban residence, type of water source, boiled or unboiled water, type of defecation site, level of personal hygiene and maternal education were associated with helminth infection. Adequate control measures are urgently needed to combat the high prevalence of intestinal helminths and risk factors in the children of Kashmir valley.

Screening for Intestinal Parasitic Infections Among Myanmar Migrant Workers in Thai Food Industry: A High-Risk Transmission

The impact of intestinal parasitic infections on public health has been neglected. Millions of Myanmar natives have migrated to work in Thailand. We performed a study of intestinal parasitic infections in Myanmar-migrants working in the Thai food industry. A total of 338 Myanmar migrant workers in a food plant at Samut Sakhon Province, Thailand, were recruited for this study. 284 (84%) returned requested stool samples. Samples were examined for intestinal parasites by means of simple smear, formalin-ether concentration, Locke-Egg-Serum medium, and Harada-Mori culture methods. We found parasites in 177 (62.3%) migrants (29 of 46 males; 148 of 238 females). The majority (89.3%) were infected with parasites transmitted by fecal-oral route, including Blastocystis hominis (41.5%), Trichuris trichiura (22.2%), Giardia lamblia (14.1%), and Ascaris lumbricoides (1.8%). Mixed infections were common (40.7%). The highest prevalence (73.3%) was found among migrants from Kohsong city, Myanmar. This high parasite infection rate in Myanmar migrant workers is an obvious public health hazard.

Soil-transmitted Helminths in Relation to Hemoglobin Status among School Children of the Kashmir Valley

Soil-transmitted helminths (STHs) remain a major threat to the health of children throughout the world, mostly in developing nations. The aim of the present study was to determine any relationship between STHs and hemoglobin status in school children of Kashmir Valley (India). Stool and blood samples were collected from 382 male and female school children in the age group of 5-15 yr from all 6 school districts of the Kashmir Valley. Finger-prick blood samples were used to collect the hemoglobin, which was then measured on-site by Sahli's acid hematin method; stool samples were processed using both simple smear and zinc sulphate concentration methods. Of the 382 children surveyed, 299 (78.27%) were infected with Ascaris lumbricoides, Trichuris trichiura, or both. Children infected by STHs were found to have lower mean values of hemoglobin than uninfected children. The present study reveals that STHs are abundant among school children of Kashmir Valley, creating a negative effect on the hemoglobin values and indicating the necessity of implementing control measures.

Prevalence of Intestinal Parasites and Associated Risk Factors among Schoolchildren in Srinagar City, Kashmir, India

Surveys on the prevalence of various intestinal parasitic infections in different geographic regions is a prerequisite for developing appropriate control strategies. The aim of the present study was to determine the prevalence of intestinal parasitic infections in schoolchildren enrolled in various schools in Srinagar City, Kashmir, India, and to assess epidemiological factors associated with the extent of endemic disease. Stool samples were collected from 514 students enrolled in 4 middle schools. The samples were processed with the use of both simple smear and zinc sulphate concentration methods, and then microscopically examined for intestinal parasites. Of the 514 students surveyed, 46.7% had 1, or more, parasites. Prevalence of Ascaris lumbricoides was highest (28.4%), followed by Giardia lamblia (7.2%), Trichuris trichiura (4.9%), and Taenia saginata (3.7%). Conditions most frequently associated with infection included the water source, defecation site, personal hygiene, and the extent of maternal education. The study shows a relatively high prevalence of intestinal parasites and suggests an imperative for the implementation of control measures.

Development and evaluation of an automated stainer for acid-fast bacilli

The current strategy for the control of tuberculosis (TB) relies on early diagnosis, and smear microscopy is an essential component of the laboratory diagnosis of TB in most countries with a high prevalence of the disease. However, even simple smear microscopy examination is far from satisfactory because staining results can vary among individual technicians. In an effort to minimize variations in manual staining procedures, we developed an automated stainer for AFB and evaluated its usefulness in comparison with manual staining. The key feature of our automated stainer is a heating apparatus required for fixation and carbol-fuchsin staining. After smear slides are placed into the machine, the entire staining process is fully automated, from fixation to final washing and drying. With the automated methods, five slides can be fixed and stained in 21 min at consistent high quality. Using sputum samples from 91 TB patients, the staining results of the automated stainer were compared blindly with those of manual staining. The concordance rate between the two methods was 94.5%. In addition, there was no significant difference in the rate of detection of AFB in the sputum samples. Although further optimization of the auto staining procedures is required, the results indicate that the automated AFB stainer developed in this study looks promising for use in clinical mycobacteriology laboratory in order to minimize personal variation during AFB staining.

A Cross-Sectional Study of Intestinal Parasitic Infections in a Rural District of West China

Parasitic infections are widespread in rural areas of West China. The remote and humid environment, traditional ways of life, contaminated potable water and limited health services all contribute to the transmission and persistence of fecal parasites. To describe the prevalence of intestinal parasitic infections in an area of West China, including its associations with demographic variables. Single fecal specimens were collected using a previously validated kit. Parasites were detected microscopically by iodine-stained smear, modified Kato-Katz thick smear, simple saline smear, test tube filter paper culture and adhesive cellophane tape anal swab. The prevalence of enteric parasites in the population was 51.7%. The proportion of individuals infected with one parasite was 36.5%, two parasites 12.7%, three parasites 3.0% and four parasites 0.08%. Parasites identified included Ascaris lumbricoides in 41.4% of all individuals tested, Ancylostoma duodenale in 17.7%, Trichurias trichuria in 8.25%, Enterobius vermicularis in 0.43%, Blastocystis hominis in 1.37%, Entamoeba coli in 0.47%, Entamoeba histolytica in 0.16%, Giardia lamblia in 0.04%, Strongyloides stercoralis in 0.04% and Clonorchis sinensis in 0.04%. The prevalence was significantly increased in women, people aged 15 to 19 years and over 80 years, the rural farm population, farmers, preschool and primary school groups, residents of a hilly rather than mountainous or plains terrain, and in intermediate income groups. The prevalence was significantly negatively associated with educational level, but not with age or income. This study supports the use of simple fecal examinations to monitor the parasite burden in rural areas of developing countries. Enteric parasites remain common in this population in rural China.

In-vitro cultivation: a sensitive method for detecting Blastocystis hominis.

Currently, the detection of human infection with Blastocystis hominis is usually based on the examination under a light microscope of faecal samples, either directly, as 'simple smears', or after some form of concentration. Whether short-term, in-vitro cultivation would increase the sensitivity of such detection remains a matter of controversy. Over 900 fresh stool specimens, from soldiers in the Royal Thai Army, were each checked for the parasite using three methods: simple smears; formalin-ethyl-acetate concentration; and cultivation in Jones' medium. Although 334 of the samples were found to be culture-positive, the parasites were only detected in 142 of the simple smears, and faecal concentration led to an even lower sensitivity (64 positive samples). In-vitro cultivation does seem worthwhile in the detection of B. hominis carriage in field studies.

Prevalence of Blastocystis hominis Carriage in Thai Army Personnel Based in Chonburi, Thailand

Blastocystis hominis is one of the most common intestinal parasites found in humans. The prevalence of B. hominis carriage in personnel who worked in the First Army Support Command, Chonburi, Thailand, was determined. Forty-four percent of 616 stool samples were positive for B. hominis using both simple smear and concentration (Formalin/ethyl acetate) techniques. The usefulness of the concentration technique in the diagnosis of B. hominis has been confirmed. Of 272 positive specimens, 75% were detected by simple smear and 25% were additionally identified by the concentration technique. The prevalence of B. hominis carriage was highest among the privates who had lived longest in this command. This finding indicates that they might have acquired B. hominis during their stay at this base. The significantly high prevalence of B. hominis carriage was found in the Ordnance Ammunition Battalion. In this battalion, privates who had education lower than the secondary school level had significantly greater risk of B. hominis carriage.

Genetic testing of the general population: ethical and informatic concerns.

Whether we like it or not, genetic testing will almost certainly become routine medical practice within the next 25 years. Integrated circuit chips already exist that can perform 400 genetic tests simultaneously, thus greatly reducing the costs. At least one company is already working on a prototype for a handheld genetic tester that would allow primary care physicians to perform hundreds or thousands of genetic tests on a simple blood smear in just a few minutes. "Genetic report cards" for children are not very far off at all. The use of such widespread testing poses a variety of ethical dilemmas. One problem that has not been appreciated sufficiently, however, is the question of how to interpret the test results. Because of the ways the genes implicated in diseases are discovered and marketed, quantitative analysis of the tests can be extremely misleading. The difficulty is that we simply do not have sufficient information about variance in genetic and other factors in the general population to make accurate projections of a patient's risk, given the presence of a gene. This uncertainty is obscured, however, when we provide the patient with a numerical analysis of risk because it is well established that people tend to overestimate the information content of numerical projections. This situation is made far worse by the fact that we do not have enough adequately trained genetic counselors to handle the load that will soon be placed on them (and studies have shown that physicians are generally very poorly prepared to act as accurate sources of information on complex genetic issues). For these reasons, I argue that access to genetic testing should be treated the same way as access to new medical procedures and medications--namely, withheld from the general public until proven safe and effective in large-scale trials. This is certain to be an unpopular policy, but it seems the only way to prevent a great deal of abuse of genetic tests.

PCR detection of mycobacteraemia in tanzanian patients with extrapulmonary tuberculosis.

In 191 Tanzanian patients admitted to hospital with suspected extrapulmonary tuberculosis (TB), TB was diagnosed in 158 patients; the remaining 33 patients had neither microbiological nor clinical evidence of TB. Mycobacterium tuberculosis was detected in the blood of 25 patients, in 92% by a polymerase chain reaction (PCR) technique and in 52% by culture of buffy coat cells. The presence of mycobacterial DNA or Mycobacterium tuberculosis bacteria in peripheral blood (positive culture) was significantly associated with HIV infection; it was detected in 22 (21.4%) of 103 HIV-seropositive patients compared to only 3 (3.5%) of 55 HIV-seronegative patients (p < 0.009). In two-thirds of the patients with mycobacteraemia, TB can be detected by simple smears from other organ sites. In patients with suspected extrapulmonary tuberculosis in whom smears from the infected site are negative or not available, PCR on blood will confirm the diagnosis within 24 hours in one third of the cases.

Role of Candida in indirect pathogenesis of antibiotic associated diarrhoea in infants.

One hundred and thirty seven isolates of Candida species were isolated from antibiotic associated diarrhoea cases and were examined to study the role of Candida in the pathogenesis of diarrhoea in infants. The quantitative estimation of yeast population by simple gram stain smear revealed more than 70% of the cases had 3+ score. The isolates further screened for detection of beta-lactamases. Among the isolated Candida sp, beta-lactamases was secreted by C. albicans, C. tropicalis, C. krusei and C. parapsilosis. Further, 46% of the Candida isolates were found to be produced 741-1110 mU/ml of beta-lactamases, suggesting that these enzyme would inactivate penicillin group of drugs and cause failure in the therapy directed against other diarrhoegenic bacteria.

Contextual analysis and intermediate cell markers enhance high-resolution cell image analysis for automated cervical smear diagnosis

Until now, efforts to automate cervical smear diagnosis have focused on analyzing features of individual cells. In a complex specimen such as that obtained from a cervical scrape, diagnostically significant cells may not be adequately represented or may elude detection by the automated technology. An approach is needed that extracts additional quantitative information from cervical smears beyond what the cell-by-cell approach can provide. A new methodology, contextual analysis, was developed to extract global quantitative information about cells, cell clusters, and background debris. This pilot study was designed to compare the efficacy of contextual analysis with high-resolution, single cell analysis and the analysis of intermediate cell markers. Thirty-four samples prepared as monolayers and stained with the Feulgen-Thionin/Congo Red stain were measured. Contextual analysis alone was able to classify 91% of the smears correctly; single cell analysis classified 94% of the cells correctly; and the intermediate cell analysis correctly identified the smear diagnosis for 84% of the cells. When all three analysis methods were combined into a simple smear level classifier, the overall smear classification accuracy was improved over those obtained using the three methodologies alone.

Resonance Raman spectroscopy of hemoglobin in intact cells: A probe of oxygen uptake by erythrocytes in rheumatoid arthritis

Resonance Raman spectra from intact viable erythrocytes can be used to study oxygen uptake in solution. In addition to changes in the oxidation state marker ( v 4), other bands due to the porphyrin ring ( v 3) and vinyl modes indicate subtle changes at oxygen pressures close to where the T/R change occurs. A comparison of whole cell and lysate spectra indicates a partial denaturation of hemoglobin on lysis. A simple smear technique is used to measure spectra from rheumatoid and normal blood. Results indicate a faster but less complete uptake of oxygen in cells from patients with rheumatoid arthritis than is the case in normal cell populations.

RARE imaging: a fast imaging method for clinical MR.

Based on the principles of echo imaging, we present a method to acquire sufficient data for a 256 X 256 image in from 2 to 40 s. The image contrast is dominated by the transverse relaxation time T2. Sampling all projections for 2D FT image reconstruction in one (or a few) echo trains leads to image artifacts due to the different T2 weighting of the echo. These artifacts cannot be described by a simple smearing out of the image in the phase direction. Proper distribution of the phase-encoding steps on the echoes can be used to minimize artifacts and even lead to resolution enhancement. In spite of the short data acquisition times, the signal amplitudes of structures with long T2 are nearly the same as those in a conventional 2D FT experiment. Our method, therefore, is an ideal screening technique for lesions with long T2.