scholarly journals Agar Plate Culture: An Alternative Sensitive Routine Laboratory Detection Method for Strongyloides stercoralis and Hookworm Parasites

2021 ◽  
Author(s):  
Tadesse HAILU ◽  
Endalkachew NIBRET ◽  
Arancha AMOR ◽  
Abaineh MUNSHEA ◽  
Melaku ANEGAGRIE
Keyword(s):  
Detection Rate ◽  
Agar Plate ◽  
Strongyloides Stercoralis ◽  
Human Infection ◽  
Diagnostic Methods ◽  
Diagnostic Agreement ◽  
Chi Square ◽  
Concentration Technique ◽  
Kappa Value ◽  
Stool Samples

Background: Human infection with Strongyloides stercoralis and hookworm parasites is usually under reported due to less sensitive diagnostic methods. Agar plate culture (APC) is the most sensitive technique for parasites having larval stage. However, using APC in routine diagnosis is uncommon. This study aimed to determine the detection rate and sensitivity of APC in comparison with formal ether concentration technique (FECT) and spontaneous tube sedimentation techniques (STSTs) for S. stercoralis and hookworm larvae. Methods: Stool samples collected from 844 schoolchildren in Amhara Regional State, northwestern Ethiopia in 2019, transported to nearby health institutions and processed by APC, FECT and STSTs. The prevalence of S. stercoralis and hookworm was computed by descriptive statistics and Chi-square. The diagnostic agreement among the three techniques was evaluated using Kappa value. Results: The overall prevalence of S. stercoralis and hookworm infections by combining the three methods was 13.2% (111/844) and 33.8% (277/844), respectively. Using APC alone, the prevalence of S. stercoralis and hookworm were found to be 10.9% (92/844) and 24.5% (207/844), respectively. Agar plate culture was 5.4 and 2.7 times respectively more sensitive than FECT and STST, with slight and fair agreement in the detection of S. stercoralis. Hookworm diagnostic agreement was moderate between APC and FECT, and APC and STST. The Kappa value between STST and FECT diagnostic methods was substantial. Conclusion: APC has a better detection rate of S stercoralis and hookworm larvae. Therefore, APC can be used as an alternative routine diagnostic method to S. stercoralis and hookworm co-endemic countries.

scholarly journals Evaluation of Two DNA Extraction Methods for Detection of Strongyloides stercoralis Infection

2018 ◽  
Vol 56 (4) ◽  
Author(s):  
Beatrice Barda ◽  
Rahel Wampfler ◽  
Somphou Sayasone ◽  
Khampheng Phongluxa ◽  
Syda Xayavong ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Strongyloides Stercoralis ◽  
Extraction Methods ◽  
Molecular Techniques ◽  
Diagnostic Methods ◽  
Content Type ◽  
Stool Samples ◽  
Dna Extraction Methods ◽  
Baermann Method

ABSTRACT Strongyloides stercoralis is present worldwide, but its prevalence is still uncertain, mainly due to the lack of sensitivity of diagnostic methods. Molecular techniques are under development, but a standardized protocol is still unavailable. We compared the sensitivity of real-time PCR, using two extraction protocols, with that of the Baermann technique. Samples were collected in the framework of the baseline screening of a randomized clinical trial evaluating moxidectin against S. stercoralis in Lao People's Democratic Republic. Two stool samples from each participant were processed by the Baermann method, and one subsample was processed by PCR. DNA was extracted using the QIAamp DNA stool minikit based on the standard protocol for the QIAamp DNA minikit (QIA) and using a modification of the QIA procedure (POL). Subsequently, all extracted samples were analyzed by real-time PCR. Overall, 95 samples were analyzed by the three diagnostic methods. Sixty-nine (72.6%) samples were positive according to the Baermann method, 25 (26.3%) by the QIA method, and 62 (65.3%) by the POL method. The sensitivities were 86% (95% confidence interval [CI], 76.7 to 92.9), 31.0% (95% CI, 21.3 to 42.6), and 78.0% (95% CI, 66.8 to 86.1) for the Baermann, QIA, and POL methods, respectively. The sensitivities calculated for each day of the Baermann method separately were 60% (48.4 to 70.8%) and 64% (52.2 to 74.2%) for days 1 and 2, respectively. In conclusion, the POL method revealed a good performance and was comparable to the Baermann test performed on two stool samples and superior to the Baermann method performed on one stool sample. Additional studies are needed to standardize a PCR protocol for S. stercoralis diagnosis.

scholarly journals Confirmation of multi-parallel quantitative real-time PCR as the gold standard for detecting soil-transmitted helminths in stool

2021 ◽  
Author(s):  
Marina Papaiakovou ◽  
Nils Pilotte ◽  
Julia Dunn ◽  
David TJ Littlewood ◽  
Rubén O Cimino ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Gold Standard ◽  
Low Cost ◽  
Strongyloides Stercoralis ◽  
Diagnostic Methods ◽  
Quantitative Real Time Pcr ◽  
Soil Transmitted Helminths ◽  
Stool Samples ◽  
Kappa Agreement

AbstractDue to its simplicity and cost-effectiveness, microscopy has seen extensive field-use as the diagnostic standard for the detection of soil-transmitted helminths (STH) in stool samples. However, the sensitivity of microscopy-based detection is inadequate in reduced-transmission settings where worm burden is oftentimes low. Equally problematic, eggs of closely related species oftentimes have indistinguishable morphologies, leading to species misidentification. In light of these shortcomings, the purpose of this study was to demonstrate multi-parallel quantitative real-time PCR (qPCR) as the new “gold standard” for STH detection. Accordingly, stool samples from non-endemic participants were spiked with limited numbers of eggs or larvae (1 to 40) of five different species of STH. DNA extracts were tested using two unique multi-parallel real-time PCR-based diagnostic methods. These methods employed different target sequences (ribosomal internal transcribed spacer, or highly repetitive non-coding regions), to evaluate the detection of DNA from as little as one egg per sample. There was a statistically significant kendall correlation between egg/larvae counts and qPCR from both methods for Trichuris trichiura (0.86 and 0.872 for NHM and Baylor assays) and a strong correlation (0.602 and 0.631 for NHM and Baylor assays, respectively) for Ascaris lumbricoides. Less strong but still significant was the Kendall Tau-b value for A. duodenale (0.408 for both) and for S. stercoralis (0.483 and 0.653, respectively). In addition, using field stool samples from rural Argentina both assays had fair to moderate kappa agreement (0.329-0.454), except for Strongyloides stercoralis (0.121) that both assays had slight agreement. In spite of the small cohort of samples, both qPCR assays, targeting of two independent genomic regions, provided reproducible results and we believe that, low cost multi-parallel quantitative real-time PCR-based diagnostics should supplant microscopy as the new gold standard for stool-based detection of soil transmitted helminths in public-health and community settings.

Increased Detection Rate of Strongyloides stercoralis by Repeated Stool Examinations Using the Agar Plate Culture Method

2007 ◽  
Vol 77 (4) ◽  
pp. 683-684 ◽  
Author(s):  
Tetsuo Hirata ◽  
Jiro Fujita ◽  
Nobuhisa Yamane ◽  
Hiroshi Nakamura ◽  
Nagisa Kinjo ◽  
...  
Keyword(s):  
Detection Rate ◽  
Agar Plate ◽  
Culture Method ◽  
Strongyloides Stercoralis

Development and Efficacy of Droplet Digital PCR for Detection of Strongyloides stercoralis in Stool

2021 ◽  
Author(s):  
Kantapong Iamrod ◽  
Apisit Chaidee ◽  
Rucksak Rucksaken ◽  
Kulthida Y. Kopolrat ◽  
Chanika Worasith ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Neglected Tropical Diseases ◽  
Agar Plate ◽  
High Sensitivity ◽  
Strongyloides Stercoralis ◽  
Digital Pcr ◽  
Immunosuppressive Drug ◽  
Stool Examination ◽  
Concentration Technique

Human strongyloidiasis is one of the neglected tropical diseases caused by infection with soil-transmitted helminth Strongyloides stercoralis. Conventional stool examination, a method commonly used for diagnosis of S. stercoralis, has low sensitivity, especially in the case of light infections. Herein, we developed the droplet digital polymerase chain reaction (ddPCR) assay to detect S. stercoralis larvae in stool and compared its performance with real-time PCR and stool examination techniques (formalin ethyl-acetate concentration technique [FECT] and agar plate culture [APC]). The ddPCR results showed 98% sensitivity and 90% specificity, and real-time PCR showed 82% sensitivity and 76.7% specificity when compared with the microscopic methods. Moreover, ddPCR could detect a single S. stercoralis larva in feces, and cross-reactions with other parasites were not observed. In conclusion, a novel ddPCR method exhibited high sensitivity and specificity for detection of S. stercoralis in stool samples. This technique may help to improve diagnosis, particularly in cases with light infection. In addition, ddPCR technique might be useful for screening patients before starting immunosuppressive drug therapy, and follow-up after treatment of strongyloidiasis.

Field survey for strongyloidiasis in eastern Uganda with observations on efficacy of preventive chemotherapy and co-occurrence of soil-transmitted helminthiasis/intestinal schistosomiasis

2010 ◽  
Vol 85 (3) ◽  
pp. 325-333 ◽  
Author(s):  
J.C. Sousa-Figueiredo ◽  
M. Day ◽  
M. Betson ◽  
C. Rowell ◽  
A. Wamboko ◽  
...  
Keyword(s):  
Agar Plate ◽  
Strongyloides Stercoralis ◽  
Diagnostic Methods ◽  
Screening Tools ◽  
Enzyme Linked Immunosorbent Assay ◽  
Preventive Chemotherapy ◽  
Geographical Patterns ◽  
Intestinal Schistosomiasis ◽  
Eastern Uganda

AbstractFollowing our previous field surveys for strongyloidiasis in western Uganda, 120 mothers and 232 children from four villages in eastern Uganda were examined, with two subsequent investigative follow-ups. As before, a variety of diagnostic methods were used: Baermann concentration, Koga agar plate and strongyloidid enzyme-linked immunosorbent assay (ELISA), as well as Kato–Katz faecal smears for detection of eggs of other helminths. At baseline, the general prevalence ofStrongyloides stercoraliswas moderate: 5.4% as estimated by Baermann and Koga agar methods combined. A much higher estimate was found by ELISA (42.3%) which, in this eastern setting, appeared to be confounded by putative cross-reaction(s) with other nematode infections. Preventive chemotherapy using praziquantel and albendazole was offered to all participants at baseline. After 21 days the first follow-up was conducted and ‘cure rates’ were calculated for all parasites encountered. Eleven months later, the second follow-up assessed longer-term trends. Initial treatments had little, if any, effect onS. stercoralis,and did not alter local prevalence, unlike hookworm infections and intestinal schistosomiasis. We propose that geographical patterns of strongyloidiasis are likely not perturbed by ongoing praziquantel/albendazole campaigns. Antibody titres increased after the first follow-up then regressed towards baseline levels upon second inspection. To better define endemic areas forS. stercoralis, careful interpretation of the ELISA is warranted, especially where diagnosis is likely being confounded by polyparasitism and/or other treatment regimens; new molecular screening tools are clearly needed.

scholarly journals Intestinal Parasitosis among the School Children of Kathmandu, Nepal

2018 ◽  
Vol 5 ◽  
pp. 89-96 ◽  
Author(s):  
Chetana Dahal ◽  
Puja Katwal ◽  
Anju Thapa ◽  
Deepa Sharma ◽  
Rama Khadka
Keyword(s):  
School Children ◽  
Private School ◽  
Tap Water ◽  
Parasitic Infection ◽  
Chi Square ◽  
Concentration Technique ◽  
Sanitary Condition ◽  
Intestinal Parasitosis ◽  
Chi Square Test ◽  
Stool Samples

Objectives: The present study was conducted to determine the intestinal parasitosis among the school children of Kathmandu, Nepal. Methods: This study was carried out from February 2018 to May 2018. During the study, a total of 194 stool samples were collected from school going children of age above 5 years to below 15 years old and processed in Padma Kanya microbiology laboratory. The detection technique used for the parasites was concentration technique (Formal-ether Sedimentation method) and iodine mount was used for slide preparation. Data were entered into SPSS and analysis was done employing Chi square test. Result: Among 194 total cases, 12.4% (24/194) children were infected with parasites where female were highly infected (70.8%) and children of age group 9-11 were highly infected (58.3%).Parasitic infection was high in non-vegetarian children (83.3%) than vegetarian, symptomatic cases (66.7%, 16/24) than asymptomatic cases, public school (66.7%, 16/24) compared with private school, higher in children who don’t wash hands with soap before meal (87.5%) than who wash hands before meal and in children not taking anti helminthic drugs (95.8%) than children taking anti-helminthic drugs recently within six months. Further, children using direct tap water for drinking purpose were highly infected than others. Conclusion: The parasitic infection among school children was found closely related to their health hygiene, sanitary condition, water consumption and other activities.  

scholarly journals Performance evaluation of Baermann techniques: The quest for developing a microscopy reference standard for the diagnosis of Strongyloides stercoralis

2021 ◽  
Vol 15 (2) ◽  
pp. e0009076
Author(s):  
Woyneshet Gelaye ◽  
Nana Aba Williams ◽  
Stella Kepha ◽  
Augusto Messa Junior ◽  
Pedro Emanuel Fleitas ◽  
...  
Keyword(s):  
Control Strategies ◽  
Strongyloides Stercoralis ◽  
Molecular Techniques ◽  
Diagnostic Methods ◽  
Superior Performance ◽  
P Value ◽  
Reference Standard ◽  
Significant Difference ◽  
Stool Samples ◽  
Composite Reference Standard

Background Soil-transmitted helminths (STH) are common in low and middle income countries where there is lack of access to clean water and sanitation. Effective diagnosis and treatment are essential for the control of STH infections. However, among STH parasites, Strongyloides stercoralis is the most neglected species, both in diagnostics and control strategies. Diagnostic methods cover different approaches, each with different sensitivities and specificities, such as serology, molecular techniques and microscopy based techniques. Of the later, the Baermann technique is the most commonly used procedure. In the literature, several ways have been described to perform the Baermann method, which illustrates the overall lack of a ‘(gold) reference standard’ method for the diagnosis of S. stercoralis infection. In this study we have evaluated the performance of three Baermann techniques in order to improve the reference standard for the microscopic diagnosis of S. stercoralis infection thereby facilitating individual case detection, mapping of the disease and proper evaluation of treatment responses. Methods/Principal findings A community based cross sectional study was conducted at Zenzelima, Bahir Dar Zuria Ethiopia. A total of 437 stool samples were collected and analyzed by the following procedures: conventional Baermann (CB), modified Baermann (MB), and modified Baermann with charcoal pre-incubation (MBCI). The diagnostic sensitivity and Negative Predictive Value (NPV) of each technique was calculated using the combination of all the three techniques as a composite reference standard. Our result indicated that larvae of S. stercoralis were detected in 151 (34.6%) stool samples. The prevalence of S. stercoralis infection based on the three diagnostic methods was 9.6%, 8.0%, and 31.3% by CB, MB, and MBCI respectively. The sensitivity and NPV for CB, MB, and MBCI were 26.7% and 70.8%, 22.1% and 69.6%, and 87.0% and 93.2%, respectively. The MBCI showed significant difference (P- value = <0.001) in the sensitivity and NPV values when compared with CB and MB values. The agreement between CB, MB, and MBCI with the composite reference standard was 31.8%, 26.7%, 89.6%, respectively. Conclusion/Significance Our results suggest the superior performance of MBCI. It is relatively easy to implement, simple to perform and comparatively cheaper. The CB is by far the commonly used method in routine diagnostic although this technique significantly underestimates the true burden of the disease and thereby contributing to the exclusion of S. stercoralis from the control strategies. Therefore, MBCI is recommended as a routine microscopy-based diagnostic test for S. stercoralis infection, particularly in settings where molecular procedures are not available.

scholarly journals Prevalence of Intestinal Parasites among Rural Inhabitants of Fouman, Guilan Province, Northern Iran with Emphasis on Strongyloides stercoralis

2020 ◽  
Author(s):  
Meysam SHARIFDINI ◽  
Laleh GHANBARZADEH ◽  
Ameneh BARIKANI ◽  
Mehrzad SARAEI
Keyword(s):  
Intestinal Parasites ◽  
Age Groups ◽  
Agar Plate ◽  
Strongyloides Stercoralis ◽  
Parasitic Infections ◽  
Blastocystis Hominis ◽  
Chi Square ◽  
Northern Iran ◽  
Confirmatory Tests ◽  
Hook Worm

Background: Intestinal parasitic infections (IPIs) are among the most important etiologies of gastrointestinal disorders in developing countries. The present study was performed to determine the prevalence of IPIs in rural inhabitants of Fouman, northern Iran. Methods: Overall, 31 villages were randomly selected during 2015-2016. Stool samples were collected from 1500 inhabitants aged 2-87. The samples were examined by direct wet smear, formalin ethyl-acetate concentration and agar plate culture. Trichrome staining and modified acid-fast staining were used as confirmatory tests for intestinal amoeba and flagellates and cryptosporidium spp., respectively. Data were analyzed with Chi-Square and Fisher exact tests using SPSS. Results: 8.06% of participants were positive for at least one intestinal parasite. The prevalence of mixed parasitic infections was 0.87%. The most prevalent IPIs were caused by Trichostrongylus spp. (3.13%), followed by Strongyloides stercoralis (1.5%), Giardia lamblia (1.3%), and Entamoeba coli (1.0%), Blastocystis hominis (0.86%), E. histolytica/dispar (0.53%), Endolimax nana (0.26%), Iodamoeba butschlii (0.13%), Trichuris trichiura (0.07%), Enterobius vermicularis (0.07%), Hook worm (0.07%) and E. hartmani (0.07%). Statistically, the prevalence of IPIs showed significant differences regarding the age groups, education status, occupation (P<0.001), and the habit of eating raw vegetables (P<0.007), whereas, the differences were insignificant with regard to sex (P=0.924) and water supply (P=0.088). Conclusion: The prevalence of IPIs, especially soil-transmitted helminthes (STHs) has sharply decreased in northern Iran. Excluding Trichostrongylus spp. and S. stercoralis, other intestinal parasites only produce a marginal and unnoticeable health problem in this area, today.

Conventional PCR for molecular diagnosis of human strongyloidiasis

Parasitology ◽  
2014 ◽  
Vol 141 (5) ◽  
pp. 716-721 ◽  
Author(s):  
R. B. SITTA ◽  
F. M. MALTA ◽  
J. R. PINHO ◽  
P. P. CHIEFFI ◽  
R. C. B. GRYSCHEK ◽  
...  
Keyword(s):  
Molecular Diagnosis ◽  
Agar Plate ◽  
Strongyloides Stercoralis ◽  
Conventional Polymerase Chain Reaction ◽  
Conventional Pcr ◽  
Pcr Assay ◽  
Culture Methods ◽  
Specific Primers ◽  
Stool Samples ◽  
Species Specific

SUMMARYStrongyloidiasis is frequently asymptomatic and diagnosis of latent infection is difficult due to limitations of current parasitological and serological methods. This study aimed to verify the use of conventional polymerase chain reaction (PCR) assay for molecular diagnosis of Strongyloides stercoralis infection. Fresh stool samples were obtained from 103 individuals: 33 S. stercoralis positive, 30 positive for other parasites and 40 negative for parasitological methods. These samples were examined by the Lutz, Rugai and agar plate culture methods and conventional PCR assay. Two sets of primers (S. stercoralis species-specific and genus-specific sets), located in the 18S ribosomal RNA gene, were used for PCR. Of the 33 samples positive for S. stercoralis by parasitological methods, 28 (84·8%) were also detected by PCR assay using species-specific primers and 26 (78·8%) using genus-specific primers. Among the stool samples negative by parasitological methods, seven (17·5%) were positive by PCR using species-specific primers and two (5·0%) using genus-specific primers. In conclusion, the conventional PCR assay described in this study using a species-specific primer pair provided a molecular method for S. stercoralis diagnosis in human stool samples.

A retrospective study comparing agar plate culture, indirect immunofluorescence and real-time PCR for the diagnosis of Strongyloides stercoralis infection

Parasitology ◽  
2017 ◽  
Vol 144 (6) ◽  
pp. 812-816 ◽  
Author(s):  
DORA BUONFRATE ◽  
FRANCESCA PERANDIN ◽  
FABIO FORMENTI ◽  
ZENO BISOFFI
Keyword(s):  
Retrospective Study ◽  
Real Time ◽  
Screening Method ◽  
Agar Plate ◽  
Strongyloides Stercoralis ◽  
Rt Pcr ◽  
Confirmatory Tests ◽  
Reasonable Approach ◽  
Proper Diagnosis ◽  
Stool Samples

SUMMARYStrongyloides stercoralis is a parasite that can cause death in immunocompromised people. A proper diagnosis is hence essential. The real-time polymerase-chain reaction (RT–PCR) is a novel, promising diagnostic method, that detects the DNA of the parasite in stool samples. In this retrospective study, we compared the sensitivity of agar plate coproculture (APC), an in-house immunofluorescence test (IFAT) and an in-house RT–PCR for the diagnosis of S. stercoralis infection. The study sample was composed by 223 samples. Samples resulting positive to APC, IFAT and RT–PCR were 20, 140 and 25, respectively. When sensitivity was calculated against a composite reference standard, serology confirmed the best performance (sensitivity 95%), followed by RT–PCR (57%) and APC (45%). In conclusion, in a non-endemic setting, serology is the best screening method, while the combination of APC and RT–PCR does not seem a reasonable approach to increase sensitivity. Both methods can have a role as confirmatory tests for selected cases.

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