Typhidot IgM as a reliable and rapid diagnostic test for typhoid fever among children in a tertiary care hospital

Background: Typhoid fever still continues to be a major public health problem in Nepal. A clinical spectrum of typhoid varies widely. It causes significant complication as well as mortality. A simple, reliable, affordable and rapid diagnostic test has been a long felt need of the clinicians to prescribe specific medication, adopt prevention of the emergence of antibiotics resistance and overall reduce the disease burden in the community.Methods: The prospective descriptive study was performed in 125 children between 2 years to 15 years of age admitted to the Pediatrics Department from September 2017 to September 2018. Blood culture, Typhidot rapid IgM were performed. MEDCALC software was used to calculate 95% confidence interval for sensitivity, specificity, predictive value positive, predictive value negative and accuracy. Kappa test was used to determine the agreement between Typhidot IgM and blood culture methods.Results: The study consisted of 125 children with acute febrile illness for more than 3 days with clinical symptomatology, consistent with typhoid fever. The reliability of Typhidot IgM in relation with blood culture and the study lighten that sensitivity 92.3% (95% CI: 63.9, 99.8), specificity 49.1% (95% CI: 39.5, 58.7), PPV 17.4% (95% CI: 14.2, 21.1), NPV 98.2% (95% CI: 89.2, 99.7) and accuracy 53.6% (95% CI: 44.5, 62.6). The two methods i.e. Typhoid IgM and blood culture shows significant agreement with p value 0.004.Conclusions: The present study demonstrates that Typhidot IgM has all the attributes of an ideal screening test.

A rare case of Ruptured Mycotic Infrarenal Aortic Aneurysm Secondary to Salmonella Species

Introduction@#Ruptured mycotic aortic aneurysm is a rare and life-threatening condition. An early and proper initiation of antibiotics aside from aneurysmal repair is of paramount importance. The typhidot IgG and IgM may help with this dilemma, especially when the blood culture is negative and during the waiting period for the the aortic sample result. @*Case@#A 47-year-old male Filipino with type 2 diabetes mellitus presented with severe back pain for one month and intermittent fever for three weeks. Complete blood count showed anemia and leukocytosis with predominance of neutrophils. On computed tomography of the aorta, a segmental calcification and wall discontinuity in the right posterolateral wall of the infrarenal abdominal aorta with heterogenous collection of blood in the retroperitoneal region was seen and aortic rupture secondary to mycotic aneurysm was considered. He underwent emergency abdominal aortic aneurysm repair with debridement, antibiotic lavage, aortoiliac grafting, anastomosis and omental packing. The typhidot IgG and IgM test was positive and was given ceftriaxone 2gm/IV every 24 hours for six weeks. Blood cultures did not reveal significant growth of any pathogen. The aortic wall culture showed heavy growth for salmonella species sensitive to ceftriaxone, confirming and guiding the management. He was then discharged improved.@*Conclusion@#A mycotic aneurysm secondary to salmonella should be one of the considerations in an adult male diabetic presenting with prolonged fever, abdominal and back pain with or without a tender pulsatile mass. The Typhidot test is an easy and affordable test that allows rapid detection of salmonella infection. Early surgical intervention and antibiotics are the treatment of choice

A comparative study of Widal test and Typhidot (IgM and IgG specific assay) test in the diagnosis of enteric fever

Background: Enteric fever (Typhoid fever) is a common systemic infectious disease worldwide, especially in developing countries like India and continues to be one of the leading causes of morbidity and mortality. It is caused by the bacterium Salmonella typhi or Salmonella paratyphi serotypes A, B and C. The clinical diagnosis of Enteric fever traditionally depends on Blood culture and Widal tests. However limitations such as longer time for Blood culture results and difficulties in the interpretation of Widal tests make them unpractical for screening patients in endemic regions and lead to misdiagnosis and missed diagnosis. Aim and objectives: Purpose of the study was to compare the sensitivity and specificity of Widal test and Typhidot based IgM and IgG assay with the Blood culture (taken as gold standard) in the diagnosis of Enteric fever. Materials and methods: This comparative study was done on 120 patients in the General Medicine Department of Indira Gandhi Institute of Medical Sciences, Patna. All patients above 11 years of age of either sex with acute febrile illness suspected to have Enteric fever were included in this study. Febrile patients with other diagnosis were excluded. Blood culture, Widal test, Typhidot (IgM and IgG) test and other routine investigations were performed in all patients. Typhidot tests and Widal tests were compared for sensitivity and specificity. Results: Out of 120 clinically diagnosed cases of Enteric fever, 18(15%) patients were Blood culture positive for Salmonella typhi, 27(22.5%) patients were positive on Widal tests and 36(30%) were Typhidot positive. Out of 18 Blood culture positive patients for Salmonella typhi, 10 patients were Jyoti Kumar Dinkar, Naresh Kumar, Chandrakishore. A comparative study of Widal test and Typhidot (IgM and IgG specific assay) test in the diagnosis of enteric fever. IAIM, 2017; 4(7): 126-130. Page 127 positive and 8 were negative on Widal testing. Out of 36 Typhidot positive patients 16 patients were positive and 20 were negative on Blood culture. Conclusions: Traditionally Blood culture and Widal test are used in the diagnosis of Enteric fever. However Typhidot (IgM & IgG assay) tests are simple and rapid screening tests that simultaneously detect and differentiate between IgM and IgG antibody to Salmonella typhi and paratyphi produced in response to infection, thus aiding in determination of current or previous exposure. It offers the advantage of early and rapid diagnosis and helps in early institution of therapy. Preliminary data have shown sensitivity and specificity of 95% and 86% respectively of Typhidot tests.

Comparative evaluation of two rapid Salmonella‑IgM tests and blood culture in the diagnosis of enteric fever.

Purpose: Enteric fever is a major public health problem in developing countries like India. An early and accurate diagnosis is necessary for a prompt and effective treatment. We have evaluated the diagnostic accuracy of two Rapid Salmonella‑IgM tests (Typhidot‑IgM and Enteroscreen‑IgM) as compared to blood culture in rapid and early diagnosis of enteric fever. Materials and Methods: A total of 2,699 patients’ serum samples were tested by Rapid Salmonella‑IgM tests and blood culture. Patients were divided into two groups. Test group—patients with enteric fever and blood culture positives for Salmonella Typhi; and three types of Controls, i.e. patients with non‑enteric fever illnesses, normal healthy controls and patients positive for S. Paratyphi‑ A. In addition to this we have also evaluated the significance of positive Salmonella‑IgM tests among blood culture‑negative cases. Results: The overall sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the Typhidot‑IgM test and Enteroscreen‑IgM test considering blood culture as gold standard were 97.29% and 88.13%, 97.40% and 87.83%, 98.18% and 92.03%, 96.15% and 82.27%, respectively. Typhidot‑IgM test was found to be significantly more sensitive and specific as compared to Enteroscreen‑IgM. Among blood culture‑negative patients, Rapid Salmonella‑IgM tests detected 72.25% additional cases of enteric fever. Although the Rapid Salmonella‑IgM tests are meant to diagnose S. Typhi only, but these tests detect S. Paratyphi‑ A also. Thirty‑eight patients who were blood culture‑positive for S. Paratyphi‑ A were also positive by Rapid Salmonella‑IgM tests. Conclusion: Rapid Salmonella‑IgM tests offer an advantage of increased sensitivity, rapidity, early diagnosis and simplicity over blood culture.

Effect of Andrographis serpyllifolia Leaves Extract on Experimentally Induced Typhoid Using Salmonella Typhi.

Aims: The aim of the study was to evaluate the effect of the standardized ethanolic extract of Andrographis serpyllifolia leaves on experimentally induced typhoid. Study Design: Single dose of 1 ml Salmonella Typhi (106 CFU/mL) was administered orally to rats to induce typhoid in rats. Blood culture test confirmed typhoid infectioned rats received orally the ethanolic extract of Andrographis serpyllifolia at dose levels of 200 and 400 mg/kg twice daily for 10 days, respectively and control animals received physiological saline. Place and Duration of Study: CSIR-National Botanical Research Institute (NBRI), Lucknow, between December 2011 and June 2013. Methodology: Leaves of Andrographis serpyllifolia was extracted with ethanol and concentrated on rotavapour. Single dose of 1 ml S. Typhi (106 CFU/mL) was administered orally to rats with the help of orogastric tube to induce typhoid in rats. After seven days, typhoid confirmed rats received the standardized extract subsequently subjected to in vitro antimicrobial susceptibility test. Results: The treatment with ethanolic extract of Andrographis serpyllifolia at dose level of 200 mg/kg showed 75.0% to 87.5% protection and 100% protection observed at higher dose of 400 mg/kg on widal, blood culture and typhidot test respectively. Biochemical test carried out on blood culture isolates confirmed the presence or absence of S. Typhi. A. serpyllifolia extract at a concentration of 1.50 mg/disc showed antimicrobial activity susceptibility against S. Typhi. Conclusion: Andrographis serpyllifolia leaves extract showed antimicrobial activity against S. Typhi and accomplished the extract of A. serpyllifolia is recommended for clinical applications in the treatment of typhoid.

Typhidot M and Diazo test vis-à-vis blood culture and Widal test in the early diagnosis of typhoid fever in children in a resource poor setting

OBJECTIVE: Typhoid fever is a major public health problem. A test which is simple, reliable and can be carried out in small laboratories is the need of the hour. We prospectively evaluated typhidot M and Diazo tests vis-à-vis blood culture and Widal test in children. METHODS: Patients aged 6 months to 12 years, having fever of more than four days duration with clinical suspicion of typhoid fever were enrolled. Patients in whom other diagnosis was made served as control. The tests under scrutiny were validated against blood culture and then all the four tests were evaluated among patients who presented in the first week of illness. RESULTS: Blood culture was positive in only 27.3 percent of the cases. Among these culture positive cases, typhidot M test had the highest sensitivity, specificity, PPV and NPV of 90 percent (95 percent CI = 74.4-96.5), 100 percent (95 percent CI = 90.1-100), 100 percent (95 percent CI = 87.5-100), and 92.1 percent (95 percent CI = 79.2-97.3) respectively. Diazo test ranked next with sensitivity, specificity, PPV and NPV of 86.7 percent (95 percent CI = 70.3-94.7), 85.7 percent (95 percent CI = 70.6-93.7), 83.9 percent (95 percent CI = 67.4-92.9), 88.2 percent (95 percent CI = 73.4-95.3) respectively. Among clinically suspected typhoid cases, the overall sensitivity, of blood culture, Widal, typhidot M, Diazo was 27.3 percent (95 percent CI = 19.8- 36.3), 64.6 percent (95 percent CI = 55.3-72.9), 89.1 percent (95 percent CI = 81.9-93.7), 80.9 percent (95 percent CI = 72.6-87.2) respectively. In the first week of illness, typhidot M showed the best sensitivity [86.2 percent (95 percent CI = 69.4-94.5)] followed by Diazo [79 percent (95 percent CI = 61.6-90.2)], Widal [41.4 percent (95 percent CI = 25.5-59.3)] and blood culture [31 percent (95 percent CI = 17.3-49.2)]. CONCLUSION: Both Typhidot M and Diazo are good screening tests for the diagnosis of typhoid fever. Typhidot M is superior to Diazo but the latter is more suitable to resource poor settings being economic and easy to perform.

Comparative Study of Dot Enzyme Immunoassay (Typhidot-M) and Widal Test in the Diagnosis of Typhoid Fever.

We compared the sensitivity and specificity of Typhidot-M and Widal test with blood culture (gold standard) for diagnosing typhoid fever in 105 children aged 1-15 years admitted with clinical suspicion of typhoid fever. Of the 105 cases, blood culture was positive for S.typhi in 41 (39%) children, Widal test was positive in 48 (45.7%) and Typhidot-M was positive in 78 (74.3%) cases. Sensitivity and specificity of Typhidot-M was 92.6% and 37.5% while sensitivity and specificity of Widal test was 34.1% and 42.8%, respectively. In children with fever of less than 7 days duration, Typhidot-M was positive in 97%, compared to 24.2% by Widal test. Typhidot-M is a simple and sensitive test for early diagnosis of typhoid fever in children.