scholarly journals Development of Moore Swab and Ultrafiltration Concentration and Detection Methods for Salmonella Typhi and Salmonella Paratyphi A in Wastewater and Application in Kolkata, India and Dhaka, Bangladesh

2021 ◽  
Author(s):  
Pengbo Liu ◽  
Makoto Ibaraki ◽  
Renuka Kapoor ◽  
Nuhu Amin ◽  
Abhishek Das ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Enteric Fever ◽  
Limit Of Detection ◽  
Systemic Infection ◽  
Salmonella Typhi ◽  
Detection Methods ◽  
Quantitative Detection ◽  
Surveillance Strategy ◽  
Wastewater Samples ◽  
Polyethylene Glycol Precipitation

AbstractEnteric fever is a severe systemic infection caused by Salmonella enterica serovar Typhi (ST) and Salmonella enterica serovar Paratyphi A (SPA). Detection of ST and SPA in wastewater can be used as a surveillance strategy to determine burden of infection and identify priority areas for water, sanitation, and hygiene interventions and vaccination campaigns. However, sensitive and specific detection of ST and SPA in environmental samples has been challenging. In this study, we developed and validated two methods for concentrating and detecting ST/SPA from wastewater: the Moore swab trap method for qualitative results, and ultrafiltration (UF) for sensitive quantitative detection, coupled with qPCR. We then applied these methods for ST and SPA wastewater surveillance in Kolkata, India and Dhaka, Bangladesh, two enteric fever endemic areas. The qPCR assays had a limit of detection of 17 equivalent genome copies (EGC) for ST and 25 EGC for SPA with good reproducibility. In seeded trials, the Moore swab method had a limit of detection of approximately 0.05-0.005 cfu/mL for both ST and SPA. In 53 Moore swab samples collected from three Kolkata pumping stations between September 2019 to March 2020, ST was detected in 69.8% and SPA was detected in 20.8%. Analysis of sewage samples seeded with known amount of ST and SPA and concentrated via the UF method, followed by polyethylene glycol precipitation and qPCR detection demonstrated that UF can effectively recover approximately 8 log10 cfu, 5 log10 cfu, and 3 log10 cfu of seeded ST and SPA in 5 L, 10 L, and 20 L of wastewater. Using the UF method in Dhaka, ST was detected in 26.7% (8/30) of 20 L drain samples with a range of 0.11-2.10 log10 EGC per 100 mL and 100% (4/4) of 20 L canal samples with a range of 1.02 - 2.02 log10 EGC per 100 mL. These results indicate that the Moore swab and UF methods provide sensitive presence/absence and quantitative detection of ST/SPA in wastewater samples, and these two methods can be used jointly or separately for Salmonella Typhi environmental surveillance.

scholarly journals Development of Moore Swab and Ultrafiltration Concentration and Detection Methods for Salmonella Typhi and Salmonella Paratyphi A in Wastewater and Application in Kolkata, India and Dhaka, Bangladesh

2021 ◽  
Vol 12 ◽  
Author(s):  
Pengbo Liu ◽  
Makoto Ibaraki ◽  
Renuka Kapoor ◽  
Nuhu Amin ◽  
Abhishek Das ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Enteric Fever ◽  
Limit Of Detection ◽  
Systemic Infection ◽  
Salmonella Typhi ◽  
Detection Methods ◽  
Quantitative Detection ◽  
Surveillance Strategy ◽  
Wastewater Samples ◽  
Polyethylene Glycol Precipitation

Enteric fever is a severe systemic infection caused by Salmonella enterica serovar Typhi (ST) and Salmonella enterica serovar Paratyphi A (SPA). Detection of ST and SPA in wastewater can be used as a surveillance strategy to determine burden of infection and identify priority areas for water, sanitation, and hygiene interventions and vaccination campaigns. However, sensitive and specific detection of ST and SPA in environmental samples has been challenging. In this study, we developed and validated two methods for concentrating and detecting ST/SPA from wastewater: the Moore swab trap method for qualitative results, and ultrafiltration (UF) for sensitive quantitative detection, coupled with qPCR. We then applied these methods for ST and SPA wastewater surveillance in Kolkata, India and Dhaka, Bangladesh, two enteric fever endemic areas. The qPCR assays had a limit of detection of 17 equivalent genome copies (EGC) for ST and 25 EGC for SPA with good reproducibility. In seeded trials, the Moore swab method had a limit of detection of approximately 0.05–0.005 cfu/mL for both ST and SPA. In 53 Moore swab samples collected from three Kolkata pumping stations between September 2019 and March 2020, ST was detected in 69.8% and SPA was detected in 20.8%. Analysis of sewage samples seeded with known amount of ST and SPA and concentrated via the UF method, followed by polyethylene glycol precipitation and qPCR detection demonstrated that UF can effectively recover approximately 8, 5, and 3 log10 cfu of seeded ST and SPA in 5, 10, and 20 L of wastewater. Using the UF method in Dhaka, ST was detected in 26.7% (8/30) of 20 L drain samples with a range of 0.11–2.10 log10 EGC per 100 mL and 100% (4/4) of 20 L canal samples with a range of 1.02–2.02 log10 EGC per 100 mL. These results indicate that the Moore swab and UF methods provide sensitive presence/absence and quantitative detection of ST/SPA in wastewater samples.

scholarly journals Enteric fever with severe pancytopenia in a four year girl

2010 ◽  
Vol 50 (180) ◽  
Author(s):  
R Pathak ◽  
A Sharma ◽  
A Khanal
Keyword(s):  
Bone Marrow ◽  
Enteric Fever ◽  
Hemophagocytic Syndrome ◽  
Systemic Infection ◽  
Salmonella Typhi ◽  
Bone Marrow Suppression ◽  
Major Health Problem ◽  
Major Health ◽  
Severe Pancytopenia ◽  
Paratyphoid Fever

Typhoid fever and paratyphoid fever (also known as enteric fever) are severe systemic illnesses caused by salmonella typhi and S. paratyphi respectively. Enteric fever is prevalent in developing countries including Nepal, where it still remains as a major health problem. There have been reports of pancytopenia with enteric fever which has been attributed to mechanisms like bone marrow suppression, infection associated hemophagocytic syndrome and disseminated intravascular coagulation. We report here a case of severe pancytopenia in enteric fever as a result of bone marrow suppression due to systemic infection. Keywords: enteric fever, pancytopenia, bone marrow suppression

scholarly journals Enteric Fever in Mediterranean North Africa

2009 ◽  
Vol 3 (10) ◽  
pp. 753-761 ◽  
Author(s):  
Khalifa Sifaw Ghenghesh ◽  
Ezzedin Franka ◽  
Khaled Tawil ◽  
Momtaz Wasfy ◽  
Salwa F. Ahmed ◽  
...  
Keyword(s):  
North Africa ◽  
Salmonella Enterica ◽  
Enteric Fever ◽  
Salmonella Typhi ◽  
Multidrug Resistant ◽  
Population Based ◽  
North African ◽  
African Region ◽  
African Countries ◽  
The Mediterranean

Typhoid fever is endemic in the Mediterranean North African countries (Morocco, Algeria, Tunisia, Libya, and Egypt) with an estimated incidence of 10-100 cases per 100,000 persons. Outbreaks caused by Salmonella enterica serovar Typhi are common and mainly due to the consumption of untreated or sewage-contaminated water. Salmonella enterica Paratyphi B is more commonly involved in nosocomial cases of enteric fever in North Africa than expected and leads to high mortality rates among infants with congenital anomalies. Prevalence among travellers returning from this region is low, with an estimate of less than one per 100,000. Although multidrug resistant strains of Salmonella Typhi and Paratyphi are prevalent in this region, the re-emergence of chloramphenicol- and ampicillin-susceptible strains has been observed. In order to better understand the epidemiology of enteric fever in the Mediterranean North African region, population-based studies are needed. These will assist the health authorities in the region in preventing and controlling this important disease.

scholarly journals Sensitivity Pattern of Salmonella Typhi from Blood Culture in Paediatric Population

2021 ◽  
Keyword(s):  
Salmonella Enterica ◽  
Enteric Fever ◽  
Pediatric Population ◽  
Tertiary Care ◽  
Salmonella Typhi ◽  
Public Health Issue ◽  
Care Hospital ◽  
Current Sensitivity ◽  
Cross Sectional ◽  
Sensitivity Pattern

Background: The bacterium Salmonella enterica serovar typhi causes typhoid fever which is a life-threatening systemic infection that mainly occurs in developing countries of the world and remains a major public health issue. Paratyphoid fever is caused by Salmonella enterica serovars Paratyphi A and B and (infrequently C). Appropriate and immediate antimicrobial therapy is required for the prevention of complications and mortality due to enteric fever. Therefore, this study is designed to investigate the current sensitivity pattern of Salmonella typhi so that appropriate antibiotics can be initiated on time. Objective: To determine the sensitivity pattern of Salmonella typhi in enteric fever among the pediatric population visiting a tertiary care hospital. Methods: This cross-sectional study was carried at the Department of Pediatrics in National Institute of Child Health Karachi from 13-12-2019 to 13-06-2020 after acquiring ethical approval from the hospital committee. There were 149 children aged 3-12 years of either gender diagnosed with enteric fever selected for this study. Patients' information was collected on pre-designed proforma. Blood of five milliliters quantity was drawn and sent to the pathology department within 12 hours of the admission. Salmonella typhi was identified by biochemical testing of the suspicious non-lactose fermenting colonies. Mueller Hinton Agar medium was used for testing antibiotic sensitivity. The sensitivity of the drug was interpreted as Sensitive, Intermediate and Resistant based on inhibition zone size. Results: The average age of the children was 5.56±2.39 years. Sensitivity for meropenem, azithromycin was 100% and 93.3% respectively while the sensitivity of ciprofloxacin was 53.7%. Ampicillin, Co-trimoxazole, Chloramphenicol and Ceftriaxone were more than 80% resistant. Conclusion: Our study confirms the sensitivity for meropenem, azithromycin, ciprofloxacin. Ampicillin, Co-trimoxazole, Chloramphenicol and Ceftriaxone showed higher resistance. This study emphasizes the need for continuous evaluation and judicious use of antimicrobials, considering the ever-changing antibiogram.

scholarly journals In vitro activity of azithromycin in Salmonella isolates from Pakistan

2011 ◽  
Vol 5 (05) ◽  
pp. 391-395 ◽  
Author(s):  
Farhana Butt ◽  
Faisal Sultan
Keyword(s):  
Salmonella Enterica ◽  
Enteric Fever ◽  
Therapeutic Option ◽  
Close Correlation ◽  
Salmonella Typhi ◽  
Public Health Issue ◽  
Disc Diffusion ◽  
Paratyphi B ◽  
High Level

Introduction: Enteric fever is caused by Salmonella enterica serovars Typhi and Paratyphi A, B and C. It is a significant public health issue in Pakistan, which is exacerbated by a high level of resistance some isolates display to drugs routinely used in treatment. Azithromycin may be a treatment option for such isolates. Methodology: We determined the minimum inhibitory concentrations (MICs) of Salmonella Typhi and Paratyphi isolates against azithromycin in an attempt to gauge its feasibility as a therapeutic option. The MICs were also compared with corresponding disc diffusion zone sizes to see if there was consistency between the two tests. We tested 45 Salmonella enterica isolates using E-tests for MIC detection and azithromycin discs with a concentration of 15µg/ml for disc diffusion testing. Results: Salmonella Typhi, Salmonella Paratyphi A, and Salmonella Paratyphi C isolates demonstrated MICs of 2-12mg/L against azithromycin, suggesting that the antibiotic could be used for therapeutic purposes. For Salmonella Paratyphi B, the MICs were 2-48 mg/L. The higher MIC indicates a need for caution when considering use of azithromycin for Salmonella Paratyphi B infections without first testing for the MIC. There was a close correlation between MICs and zone sizes which was statistically significant. Conclusions: Our results indicate azithromycin is a potential therapeutic option for enteric fever. Standardized laboratory testing methods and interpretation for azithromycin  against Salmonella enterica would allow laboratories to report upon this antibiotic with confidence.

scholarly journals A Rapid and Sensitive Fluorescent Microsphere-Based Lateral Flow Immunoassay for Determination of Aflatoxin B1 in Distillers’ Grains

Foods ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2109
Author(s):  
Zifei Wang ◽  
Pengjie Luo ◽  
Baodong Zheng
Keyword(s):  
Aflatoxin B1 ◽  
High Performance ◽  
Animal Feed ◽  
Limit Of Detection ◽  
Lateral Flow ◽  
Distillers Grains ◽  
Detection Methods ◽  
Lateral Flow Immunoassay ◽  
Quantitative Detection ◽  
Fluorescent Microsphere

Aflatoxin B1 (AFB1) is a toxic compound naturally produced by the genera Aspergillus. Distillers’ grains can be used as animal feed since they have high content of crude protein and other nutrients. However, they are easily contaminated by mycotoxins, and currently there are no rapid detection methods for AFB1 in distillers’ grains. In this study, a lateral flow immunoassay (LFIA) based on red fluorescent microsphere (FM), is developed for quantitative detection of AFB1 in distillers’ grains. The whole test can be completed within 15 min, with the cut-off value being 25.0 μg/kg, and the quantitative limit of detection (qLOD) being 3.4 μg/kg. This method represents satisfactory recoveries of 95.2–113.0%, and the coefficients of variation (CVs) are less than 7.0%. Furthermore, this technique is successfully used to analyze AFB1 in real samples, and the results indicates good consistency with that of high-performance liquid chromatography (HPLC). The correlation coefficient is found to be greater than 0.99. The proposed test strip facilitates on-site, cost-effective, and sensitive monitoring of AFB1 in distillers’ grains.

scholarly journals A review of clinical profile, complications and antibiotic susceptibility pattern of extensively drug-resistant (XDR) Salmonella Typhi isolates in children in Karachi.

2020 ◽  
Author(s):  
Saba Shahid ◽  
Marvi Mahesar ◽  
Nida Ghouri ◽  
Saba Noreen
Keyword(s):  
Enteric Fever ◽  
Clinical Course ◽  
Pediatric Population ◽  
Clinical Manifestations ◽  
Systemic Infection ◽  
Retrospective Chart Review ◽  
Signs And Symptoms ◽  
Salmonella Typhi ◽  
Drug Resistant ◽  
Extensively Drug Resistant

Abstract Background: Enteric fever is a systemic infection, which can be caused by Salmonella enterica; Typhi and Paratyphi A. Over time, Salmonella Typhi has developed resistance to antibiotics resulting in the emergence of extensively drug-resistant (XDR) enteric fever. WHO estimated 5274 cases of XDR Enteric fever in Karachi from November 2016 to December 2019. This study aims to determine clinical course, complications and outcomes of XDR enteric fever among the pediatric population coming to Indus HospitalMethods: A retrospective chart review of pediatric patients (aged one month to 15 years) seen in Indus Hospital between July 2017 to December 2018 was conducted. A pre-designed data abstraction form was used to record detailed information about seasonality and distribution of cases, demographic details, signs and symptoms, clinical course, treatment, complications and outcomes of the cases treated for XDR Enteric feverResults: Six hundred and eighty children were included in the study. The median (IQR) age of the patients was 5 (2-8) years. More than half (n=391, 57.5%) of the patients were males. Most common clinical manifestations included fever, vomiting and diarrhea, noted in 680 (100%), 242 (35%) and 174 (25%) patients. Outcomes of 270 (39.7%) patients were recorded. Others were lost to follow up [351 (51.6%)], referred out [52 (7.6%)] or left against medical advice [7 (1%)]. 266 (39.1%) patients were cured, and four children (0.6%) expired. Seventy-eight patients (82%) and 15 patients (16.3%) got cured on Azithromycin and Meropenem alone while 157 on a combination of drugs.Conclusion: Our review indicated that children under five years of age were affected more with XDR Enteric fever. Meropenem and Azithromycin, either alone or in combination were the most effective antibiotics for treating XDR Enteric fever in children coming to Indus hospital

scholarly journals Label-free fiber-optic spherical tip biosensor to enable picomolar-level detection of CD44 protein

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aliya Bekmurzayeva ◽  
Zhannat Ashikbayeva ◽  
Zhuldyz Myrkhiyeva ◽  
Aigerim Nugmanova ◽  
Madina Shaimerdenova ◽  
...  
Keyword(s):  
Fiber Optic ◽  
Limit Of Detection ◽  
Refractive Index Change ◽  
Protein Detection ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Detection Methods ◽  
Quantitative Detection ◽  
Label Free

AbstractIncreased level of CD44 protein in serum is observed in several cancers and is associated with tumor burden and metastasis. Current clinically used detection methods of this protein are time-consuming and use labeled reagents for analysis. Therefore exploring new label-free and fast methods for its quantification including its detection in situ is of importance. This study reports the first optical fiber biosensor for CD44 protein detection, based on a spherical fiber optic tip device. The sensor is easily fabricated from an inexpensive material (single-mode fiber widely used in telecommunication) in a fast and robust manner through a CO2 laser splicer. The fabricated sensor responded to refractive index change with a sensitivity of 95.76 dB/RIU. The spherical tip was further functionalized with anti-CD44 antibodies to develop a biosensor and each step of functionalization was verified by an atomic force microscope. The biosensor detected a target of interest with an achieved limit of detection of 17 pM with only minor signal change to two control proteins. Most importantly, concentrations tested in this work are very broad and are within the clinically relevant concentration range. Moreover, the configuration of the proposed biosensor allows its potential incorporation into an in situ system for quantitative detection of this biomarker in a clinical setting.

scholarly journals Fluoroquinolone-resistant Salmonella typhi infection: a report of two cases in South Africa

2018 ◽  
Vol 33 (2) ◽  
pp. 54-56
Author(s):  
N. Schellack ◽  
E. Bronkhorst ◽  
C. Maluleka ◽  
L. Hunt ◽  
P. Srinivas ◽  
...  
Keyword(s):  
South Africa ◽  
Salmonella Enterica ◽  
Systemic Infection ◽  
Salmonella Typhi ◽  
Fluoroquinolone Resistance ◽  
Life Threatening ◽  
Paratyphoid Fever

Typhoid and paratyphoid fever are acute, life-threatening febrile illnesses caused by systemic infection with the bacterium Salmonella enterica. Nineteen cases were reported in South Africa in 2016. We report on two cases of bacteraemic invasive S. typhi with fluoroquinolone resistance.

scholarly journals Development of a Simple, Peripheral-Blood-Based Lateral-Flow Dipstick Assay for Accurate Detection of Patients with Enteric Fever

2016 ◽  
Vol 23 (5) ◽  
pp. 403-409 ◽  
Author(s):  
Iqbal Hassan Khan ◽  
M. Abu Sayeed ◽  
Nishat Sultana ◽  
Kamrul Islam ◽  
Jakia Amin ◽  
...  
Keyword(s):  
Blood Culture ◽  
Salmonella Enterica ◽  
Enteric Fever ◽  
Systemic Infection ◽  
Lymphocyte Culture ◽  
Lateral Flow ◽  
True Negative ◽  
Content Type ◽  
Mortality And Morbidity ◽  
Resource Limited

ABSTRACTEnteric fever is a systemic infection caused by typhoidal strains ofSalmonella entericaand is a significant cause of mortality and morbidity in many parts of the world, especially in resource-limited areas. Unfortunately, currently available diagnostic tests for enteric fever lack sensitivity and/or specificity. No true clinically practical gold standard for diagnosing patients with enteric fever exists. Unfortunately, microbiologic culturing of blood is only 30 to 70% sensitive although 100% specific. Here, we report the development of a lateral-flow immunochromatographic dipstick assay based on the detection ofSalmonella entericaserovar Typhi (S. Typhi) lipopolysaccharide (LPS)-specific IgG in lymphocyte culture secretion. We tested the assay using samples from 142 clinically suspected enteric fever patients, 28 healthy individuals residing in a zone where enteric fever is endemic, and 35 patients with other febrile illnesses. In our analysis, the dipstick detected all blood culture-confirmedS. Typhi cases (48/48) and 5 of 6Salmonella entericaserovar Paratyphi A blood cultured-confirmed cases. The test was negative in all 35 individuals febrile with other illnesses and all 28 healthy controls from the zone of endemicity. The test was positive in 19 of 88 individuals with suspected enteric fever but with negative blood cultures. Thus, the dipstick had a sensitivity of 98% compared to blood culture results and a specificity that ranged from 78 to 100% (95% confidence interval [CI], 70 to 100%), depending on the definition of a true negative. These results suggest that this dipstick assay can be very useful for the detection of enteric fever patients especially in regions of endemicity.

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