agar and Strongyloidiasis

Research on diagnostic methods have strongyloidiasis divergent validity and incomplete by not reporting data on safety, efficiency and performance diagnosis.. To assess validity, performance, efficiency and safety of four diagnostic conventional parasitological methods for detection of Strongyloides stercoralis infection in the period 1980-2013.. Systematic review with meta-analysis, exhaustive and reproducible literature search of six databases. Quality of the articles was assessed and meta-analysis was performed under the random effects model, calculating sensitivity, specificity, likelihood ratios, predictive values, proportion of false results, accuracy, odds ratio and Youden index J and ROC curve using Meta-DiSc(es) and Epidat 3.1.. 11 studies with 9,025 individuals were included. Sensitivity of the Baermann method was 72%, positive likelihood ratio (LR+) 228 and negative likelihood ratio (LR-) 0.32. The agar plate culture (APC) had a sensitivity of 89%, LR+ 341 and LR- 0.11. Stool sensitivity was 21%, LR+ 67 and LR- 0.67. Sensitivity of the formol-ether concentration was 48%, LR+ 110 and LR- 0.59. Areas under the ROC curve were 0.999 in Baermann and APC, 0.977 in the stool and 0.829 in formalin-ether concentration; specificity was 100% in all tests.. The four conventional parasitological methods tested in this study to detect S. stercoralis can be helpful; however, agar plate culture and Baermann method are best suited.

Topics: Agar; Animals; Feces; Humans; Sensitivity and Specificity; Strongyloides stercoralis; Strongyloidiasis

Agar-plate culture (APC) remains the most sensitive parasitological technique for S. stercoralis diagnosis. Although it was first described three decades ago, the time of incubation of the plates is neither a commonly described feature nor usually standardized. The aim of the study was to analyze the required time to detect S. stercoralis larvae in APC.. A prospective laboratory-based study including all patients with at least one positive APC was performed. The plates were incubated at room temperature for 7 days. Clinical, analytical and parasitological features including results of the direct visualization of the stool (DV) after formalin-ether concentration and time-to-detection (TTD) of the larvae in APC were recorded.. A total of 141 samples from 75 patients had a positive APC. In 49 of them (65.3%) three or more stool samples were processed for direct visualization (DV) and APC. Of these 49 patients, 8 (16.3%) were also diagnosed with DV and 41 (83.7%) were diagnosed only with APC. In 38 samples from 23 (30.7%) patients, the TTD was below 2 days, while in 27 samples from 13 (17.3%) patients, the larvae were detected on the 6th and 7th day.. Direct visualization failed to detect S. stercoralis in most of the patients that were diagnosed with APC. Incubation periods below 2 and 5 days would miss an important percentage of infections. At least 7 days of incubation of the APC are required to detect presumably low-burden chronic infections in non-endemic countries.

Topics: Agar; Animals; Feces; Formaldehyde; Humans; Prospective Studies; Strongyloides stercoralis; Strongyloidiasis

Strongyloides stercoralis is a nematode endemic to subtropical and tropical regions that may cause asymptomatic carriage, peripheral eosinophilia, cutaneous, gastrointestinal, and pulmonary disease, or hyperinfection syndrome. Conventional diagnostic methods for strongyloidiasis include feces microscopy and culture, with low sensitivity in chronic infection due to the low helminth burden, and serology, which may be prone to false-negative results with immunocompromise and false-positive results with other infections and immunological disorders. We evaluated a laboratory-developed real-time polymerase chain reaction (RT-PCR), detecting the 18S SSU ribosomal RNA gene, compared with conventional diagnostic methods, using serology via ELISA as the gold-standard. The population studied included tertiary hospital inpatients and outpatients residing in a nonendemic area. Seven hundred fifty unfixed stool specimens submitted sequentially between 2014 and 2018 were tested for S. stercoralis via microscopy and RT-PCR. Agar plate culture (APC), Harada-Mori culture (HMC), and ELISA were performed in conjunction with 141, 135, and 177 of the specimens, respectively. RT-PCR yielded 13 positive and 730 negative results, with inhibition in seven specimens. ELISA yielded 53 positive, 18 equivocal, and 106 negative results. Results for direct diagnostic methods obtained after treatment with ivermectin were excluded from the performance analysis. Compared with ELISA, RT-PCR, microscopy, APC, and HMC exhibited sensitivities of 38%, 6%, 3%, and 0%, respectively, and specificities of 100%. Given the low sensitivities commensurate with testing a population with remote infection and thus low parasite burden, we recommend a combination of serological and molecular diagnostic testing to achieve the best balance of sensitivity and specificity.

Topics: Agar; Animals; Feces; Humans; Ivermectin; Real-Time Polymerase Chain Reaction; RNA, Ribosomal, 18S; Strongyloides stercoralis; Strongyloidiasis

Strongyloides stercoralis infection causes gastrointestinal symptoms and can lead to severe disease in immunocompromised hosts. Live larvae are passed in feces, encouraging the common use of diagnosis by cultivation methods including agar plate culture (APC), the gold-standard technique. Nevertheless, APC has limitations, especially since there can be considerable day-to-day fluctuations in numbers of larvae produced. Herein, we collected stool samples from heavily infected subjects with strongyloidiasis in Khon Kaen Province, Thailand, to evaluate modifications (temperature, pH, nutrition source and salinity) to APC conditions to maximize the number of S. stercoralis worms counted. Best results were obtained using a modified APC with the following conditions: pH 6.0, 0.5% of NaCl, addition of yeast extract for nutrition and incubation at 29-30 °C. This modified APC was more sensitive for detection of S. stercoralis than was standard APC or the formalin-ethyl acetate concentration technique. In brief, this finding suggests that a modification of standard APC conditions increases the counts of S. stercoralis.

Topics: Adult; Agar; Aged; Animals; Feces; Humans; Male; Middle Aged; Strongyloides stercoralis; Strongyloidiasis

We aimed to compare the efficacy of modified agar plate fecal culture (mAPC) and standard agar plate culture (sAPC) for diagnosis of Strongyloides stercoralis infection in a community at Khon Kaen Province, Thailand. Fecal samples were collected from participants individually (n = 1076) and were tested using these two methods. Modified APC and sAPC detected 129 (11.99%) and 91 (8.46%) infected individuals, respectively. Thirty-eight participants were negative according to sAPC, but positive for mAPC. Moreover, in the participants who were positive for both methods, the number of worm developmental stages obtained was higher for mAPC than for sAPC. Our study suggests that mAPC is an effective and useful tool for S. stercoralis diagnosis and can be applied for mass-screening in community and/or control programs.

Topics: Adult; Agar; Aged; Aged, 80 and over; Animals; Diagnostic Techniques and Procedures; Feces; Female; Humans; Male; Mass Screening; Middle Aged; Sensitivity and Specificity; Strongyloides stercoralis; Strongyloidiasis; Thailand

Strongyloides 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.

Topics: Agar; Animals; Antibodies, Helminth; Culture Media; DNA, Helminth; Feces; Fluorescent Antibody Technique, Indirect; Humans; Real-Time Polymerase Chain Reaction; Retrospective Studies; RNA, Helminth; RNA, Ribosomal; Sensitivity and Specificity; Strongyloides stercoralis; Strongyloidiasis

A comparative study was carried out to evaluate the Strongyloides stercoralis infections in children and dogs inside and outside the segregated settlement in Medzev, Eastern Slovakia, and a survey of the soil within the settlement was included. Applying the Koga agar plate (KAP) culture method and microscopy examination of stool samples collected from 60 Roma and 21 nonRoma children, no larvae of S. stercoralis were detected but eggs of three nematodes (Ascaris lumbricoides, Trichuris trichiura, and Enterobius vermicularis) and cysts of two protozoan endoparasites (Giardia duodenalis and Cryptosporidium spp.) were often found. However, immunoenzymatic assay (ELISA) for the evidence of IgG antibodies against S. stercoralis showed 33.3% seroprevalence in Roma children and 23.8% prevalence in children from the majority population, attending the same school. Eosinophilia was regularly present in children with exclusive infection of S. stercoralis (eight cases) as well as in individuals suffering from mixed infections of S. stercoralis and some of the above listed parasites (16 cases); high eosinophil counts sometimes, but not always, occurred in parasitized children lacking S. stercoralis antibodies. A comparison of S. stercoralis in dogs from the settlement (40 dogs) and from a distant dog shelter (20 dogs) did not reveal remarkable differences: the direct microscopy of faecal samples revealed rhabditiform larvae in 13.3% of the dogs from the settlement (4/30) and in 10.0% of the dogs from the shelter (2/20). Out of blood samples collected from the second dog group, 55% of the dogs contained antibodies against S. stercoralis. In the soil collected from 14 various locations within the settlement, S. stercoralis larvae were observed in two samples (14.3%); however, 13 samples (92.9%) were positive for human or dog endoparasites of the genera Ancylostoma, Ascaris, Toxocara, Toxascaris, Trichuris, and Hymenolepis.

Topics: Agar; Ancylostoma; Animals; Ascaris; Ascaris lumbricoides; Child; Child, Preschool; Coinfection; Dog Diseases; Dogs; Enterobius; Enzyme-Linked Immunosorbent Assay; Feces; Female; Giardia lamblia; Humans; Male; Prevalence; Seroepidemiologic Studies; Slovakia; Soil; Strongyloides stercoralis; Strongyloidiasis; Toxocara

Topics: Agar; Animals; Diarrhea; Female; Humans; Larva Migrans; Strongyloides stercoralis; Strongyloidiasis

To clarify the efficacy of repeated stool examinations by the agar plate culture method for the detection of Strongyloides stercoralis infection, 4,071 stool samples collected from 2,406 patients > 50 years of age in Ryukyu University Hospital were examined. The cumulative detection rate of S. stercoralis infection was 4.7% (112/2,406). At the first, second, third, and beyond fourth examinations, the detection rates were 3.6% (86/2,406), 1.5% (12/786), 2.6% (10/392), and 2.0% (4/198), respectively. From these results, the cumulative detection rate was estimated to be 7.4% when three stool samples were examined for all patients. Our study showed that repeated stool examinations increase the sensitivity of detection of S. stercoralis infection.

Topics: Agar; Aged; Aged, 80 and over; Animals; Culture Media; Culture Techniques; Feces; Female; Humans; Male; Middle Aged; Parasite Egg Count; Sensitivity and Specificity; Strongyloides stercoralis; Strongyloidiasis

Strongyloides stercoralis is a neglected soil-transmitted helminth species, and there is a lack of parasitologic and epidemiologic data pertaining to this parasite in China and elsewhere. We studied the local occurrence of S. stercoralis in a village in Yunnan province, China, and comparatively assessed the performance of different diagnostic methods.. Multiple stool samples from a random population sample were subjected to the Kato-Katz method, an ether-concentration technique, the Koga agar plate method, and the Baermann technique. Among 180 participants who submitted at least 2 stool samples, we found a S. stercoralis prevalence of 11.7%. Males had a significantly higher prevalence than females (18.3% versus 6.1%, p = 0.011), and infections were absent in individuals <15 years of age. Infections were only detected by the Baermann (highest sensitivity) and the Koga agar plate method, but neither with the Kato-Katz nor an ether-concentration technique. The examination of 3 stool samples rather than a single one resulted in the detection of 62% and 100% more infections when employing the Koga agar plate and the Baermann technique, respectively. The use of a mathematical model revealed a 'true' S. stercoralis prevalence in the current setting of up to 16.3%.. We conclude that S. stercoralis is endemic in the southern part of Yunnan province and that differential diagnosis and integrated control of intestinal helminth infections needs more pointed emphasis in rural China.

Topics: Adolescent; Adult; Agar; Aged, 80 and over; Animals; Child; Child, Preschool; China; Diagnosis, Differential; Ethnicity; Family Characteristics; Feces; Female; Geography; Humans; Intestines; Male; Middle Aged; Prevalence; Rural Population; Sanitation; Strongyloides stercoralis; Strongyloidiasis; Surveys and Questionnaires

Strongyloidiasis, caused by Strongyloides stercoralis, is diagnosis considered as a challenge to clinician and laboratory technician. Because the auto-infective larvae are difficult to eradicate, one regimen dose may be in-sufficient and re-treatment of patients on two occasions, at 1 and 2 months after the initial treatment dose was recommended. This re-treatment regimen has yet to be proven in clinical trials. This study was performed on 24 patients who completed the study and having Strongyloides larvae in their stool obtained from Mansoura University Hospitals. Each stool sample was examined by direct saline smear, the formalin-ether sedimentation technique and agar plate culture. Patients were treated with Mirazid double course for a month to be followed up by stool examination by traditional method and agar plate culture for three consecutive months. In this study five cases out of 24 were asymptomatic (20.8%). Symptoms include abdominal manifestations as nausea and vomiting (16.7%), epi-gastric pain and nausea (12.5%), generalized abdominal pain (12.5%), chronic diarrhea (16.7%), irregular bowel habit (8.3%), and urticaria with abdominal pain (4.2%). Agar plate culture gave 100% positivity, even in cases were negative by coprological methods either direct smear and/or sedimenttation technique. All cases were cured by Mirazid given for one month except three resistant cases. Only one case responded to repeated course of Mirazid, while the other two cases still had larvae in their stool by agar culture plate. On combined therapy of both Mirazid and Mebendazole, larvae could be eliminated from their stool as approved by agar plate culture.

Topics: Adolescent; Adult; Agar; Aged; Animals; Anthelmintics; Drug Resistance; Feces; Humans; Intestinal Diseases, Parasitic; Male; Middle Aged; Parasite Egg Count; Strongyloides stercoralis; Strongyloidiasis; Treatment Outcome

The quantitative formalin ethyl acetate concentration technique (QFEC) was compared to agar plate culture (APC) for the detection of Strongyloides stercoralis larvae. QFEC could substitute for APC only when the parasite load was higher than 50 larvae per g of stool. This study serves as a good reminder to those conducting stool exams about the sensitivity and specificity limitations of both techniques.

Topics: Acetates; Agar; Animals; Centrifugation; Feces; Formaldehyde; Humans; Intestinal Diseases, Parasitic; Larva; Parasitology; Strongyloides stercoralis; Strongyloidiasis

The performances of the gelatin particle agglutination test (GPAT) and enzyme-linked immunosorbent assay (ELISA) for the diagnosis of strongyloidiasis with reference to the results of the agar plate culture technique (APCT) were evaluated with samples from 459 individuals from communities in northeast Thailand where strongyloidiasis is endemic. The prevalence of strongyloidiasis in five sample groups determined by GPAT varied between 29.3 and 61.5% (mean, 38.8%). ELISA and APCT, employed concurrently, gave lower prevalence rates of 27.5% (range, 21.6 to 42.1%) and 22.7% (range, 12.7 to 53.8%), respectively. By using APCT as the standard method, the sensitivity of GPAT was generally higher than that of ELISA (81 versus 73%). The specificity of GPAT was slightly lower than that of ELISA (74 versus 86%). The resulting GPAT titers exhibited positive linear relationships with the ELISA values (optical density at 490 nm) (P < 0.05), which suggests that the GPAT titer also reflects the levels of specific antibody comparable to those reflected by the ELISA values. Based on the relative ease and simplicity of use of the technique as well as the acceptable rates of sensitivity and specificity of the test, GPAT is more practical for screening for strongyloidiasis than the conventional ELISA.

Topics: Agar; Agglutination Tests; Animals; Antibodies, Helminth; Culture Media; Enzyme-Linked Immunosorbent Assay; Gelatin; Humans; Prevalence; Sensitivity and Specificity; Serologic Tests; Strongyloides stercoralis; Strongyloidiasis

The host-finding behavior of Strongyloides stercoralis infective larvae was examined by in vitro agarose assay method. As human body fluid contains 0.85% (ca 0.15 molar) NaCl, various concentrations of sodium chloride, from 0.5M to 0.01M (7 steps), were examined. Many larvae were attracted at concentrations between 0.5 and 0.05M of sodium chloride. The concentration of 0.05M attracted the most larvae. The concentration of 0.02M of sodium chloride showed greatly reduced larval attraction compared with 0.05M. Therefore, the threshold concentration was determined as 0.05M. Then, 0.05M of chemicals were examined in a further experiment. Chloride compounds (NaCl, KCl, CaCl2, MgCl2) were investigated. These chemicals are components of human body fluids. Distilled water was used as the control in all experiments. Only sodium chloride attracted the larvae. Next, alkaline compounds were examined [NaOH, KOH, Ca(OH)2, and Mg(OH)2]. Larvae accumulated only at the NaOH site. The results suggested that the Na cation is important for larval attraction. A high pH value did not influence attraction at all. Next, human serum was tested. The human serum used was from normal serum to 1:32 diluted sera by distilled water (7 steps). Hierarchical attraction was seen according to serum concentration. Next, human sweat was collected from a limited zone of chest skin where only eccrine glands were distributed. Non-diluted sweat attracted the most larvae. Sweat might act as one of the most probable factors for infection by this skin-penetrating nematode.

Topics: Agar; Animals; Cations; Feeding Behavior; Host-Parasite Interactions; Humans; In Vitro Techniques; Larva; Serum; Sodium; Strongyloides stercoralis; Strongyloidiasis; Sweat

Topics: Agar; Animals; Bacteria; Colony Count, Microbial; Culture Media; Humans; Larva; Locomotion; Male; Sputum; Strongyloides stercoralis; Strongyloidiasis

Human immunodeficiency virus (HIV) and intestinal parasites are common in Brazil. Previous studies have shown that infection with Strongyloides stercoralis is frequently associated with HIV infection. Strongyloidiasis is difficult to diagnosis and stool examination with conventional techniques fails to detect the helminth larvae. We made a prospective study, to test the efficacy of the agar plate technique to detect S. stercoralis in 211 HIV-positive patients and 213 HIV-negative patients in the city of Itajaí, Brazil, between September 2001 and June 2002. The feces samples of these patients were processed and analyzed according to the following methods: Lutz, formalin ethyl acetate, Baermann, Harada-Mori and agar plate culture. HIV-positive patients were more frequently infected by S. stercoralis (odds ratio= 5,.687). Among the methods used on fecal specimens, the larvae of S. stercoralis were most efficiently detected by the agar plate (69.7%) method, followed by the Baermann and the formalin ethyl acetate methods (48.5%) (P=0.01), Lutz (42.4%) (P=0.01), and Harada-Mori culture (24%) (P=0.001). Therefore agar plate culture is the most efficient method for the detection of S. stercoralis larvae and this technique should be the test of choice, especially in immunocompromised patients.

Topics: Adolescent; Adult; Agar; Animals; Culture Media; Feces; Female; HIV Infections; Humans; Intestinal Diseases, Parasitic; Male; Parasite Egg Count; Prospective Studies; Sensitivity and Specificity; Strongyloides stercoralis; Strongyloidiasis

The diagnosis of Strongyloides stercoralis infections is routinely made by microscopic observation of larvae in stool samples, a low sensitivity method, or by other, most effective methods, such as the Baermann or agar culture plate methods. We propose in this paper a practical modification of Baermann method. One hundred and six stool samples from alcoholic patients were analyzed using the direct smear test, agar culture plate method, the standard Baermann method, and its proposed modification. For this modification the funnel used in the original version of the method is substituted by a test tube with a rubber stopper, perforated to allow insertion of a pipette tip. The tube with a fecal suspension is inverted over another tube containing 6 ml of saline solution and incubated at 37 degrees C for at least 2 h. The saline solution from the second tube is centrifuged and the pellet is observed microscopically. Larva of S. stercoralis were detected in six samples (5.7%) by the two versions of the Baermann method. Five samples were positive using the agar culture plate method, and only in two samples the larva were observed using direct microscopic observation of fecal smears. Cysts of Endolimax nana and Entamoeba histolytica/dyspar were also detected in the modification of Baermann method. Data obtained by the modified Baermann method suggest that this methodology may helps concentrate larvae of S. stercoralis as efficiently as the original method.

Topics: Agar; Animals; Culture Media; Feces; Humans; Parasitology; Sensitivity and Specificity; Strongyloides; Strongyloidiasis

Creeping eruption caused by Strongyloides stercoralis is called larva currens, while those caused by other parasites are called larva migrans. To detect the parasite, the direct smear method was used. However, this method is not very sensitive in detecting S. stercoralis. A 62-year-old male with polyarteritis nodosa cutanea had an erythematous creeping eruption in various regions, such as his lumbar region, abdomen and thigh. The diagnosis of larva currens was made by the clinical appearance and the detection of S. stercoralis in his feces using the direct smear method and the agar plate method. This is the first reported case of larva currens in Japan. The agar plate method was useful and more sensitive than the usual direct smear method for detecting the S. stercoralis in feces and for elucidating the effects of treatment with antiparasitic drugs.

Topics: Adult; Agar; Animals; Diagnosis, Differential; Humans; Male; Sensitivity and Specificity; Strongyloides stercoralis; Strongyloidiasis

An examination of 320 random stool samples from patients aged 7-60 years in Kafr-Sakr Hospital, was done to compare the efficacy of modified agar plate method to traditional method for diagnosis of Strongyloides stercoralis infection. Out of 320 cases examined 27 were positive for strongyloidiasis by all means. The traditional methods detected 37% and 48.1% from the positive cases by single and repeated 3 days examination respectively. The modified agar plate detected 70.3% and 96.2% among positive cases by single and 3 days examination respectively. The modified agar plate was twice efficient than the traditional methods. Precautions taken to obtain the best result were discussed. Considering the other advantages of this technique, it was concluded that it may eventually become the test of choice in diagnosis of strongyloidiasis.

Topics: Adolescent; Adult; Agar; Animals; Child; Feces; Female; Humans; Intestinal Diseases; Male; Middle Aged; Strongyloides stercoralis; Strongyloidiasis

An agar plate method for the diagnosis of intestinal strongyloidiasis was compared to the standard formalin-ethyl acetate concentration method. A total of 13 of 225 patients with eosinophilia had positive stools for strongyloides larva by agar plate compared to six of 225 by the formalin-ethyl acetate method (P = .0455). Nine positive stool specimens by the agar plate method were tested by the Baermann technique, and five were positive. The agar plate method is a sensitive and efficient technique for the diagnosis of strongyloidiasis.

Topics: Acetates; Agar; Animals; Feces; Formaldehyde; Humans; Intestinal Diseases, Parasitic; Parasitology; Strongyloides stercoralis; Strongyloidiasis

Topics: Agar; Animals; Ether; Feces; Filtration; Formaldehyde; Humans; Strongyloides stercoralis; Strongyloidiasis

The sensitivity of the agar plate method for the diagnosis of Strongyloides stercoralis was studied experimentally. Results demonstrated that this method was sensitive enough to detect S. stercoralis even when only a few worms were present.

Topics: Agar; Aged; Animals; Feces; Female; Humans; Parasitology; Sensitivity and Specificity; Strongyloides; Strongyloidiasis