Papers by Sanjay Doiphode
International Journal of Health Sciences, 2016
To assess the risk of gastroenteritis associated with bacterial foodborne pathogens and identify ... more To assess the risk of gastroenteritis associated with bacterial foodborne pathogens and identify associated factors in a highly diverse population. A series of case-control studies were carried out to address the stated objective. The study population consisted of individuals who were admitted to the Hamad Medical Corporation hospitals and stool analysis indicated positive findings to Campylobacter spp., Escherichia coli, or Salmonella spp. between the period of August 2009 and December 2012. Cases were defined based on positive stool analysis to any of the previously mentioned organisms. Control group was similar to case group but negative in stool analysis to the particular pathogen under study. Association between demographic characteristics and likelihood of pathogen infection were investigated using logistic regression analysis. A total of 423 individuals diagnosed with these bacterial pathogens were randomly enrolled in the study. The majority of cases were infected by E.coli....
Journal of Food Safety and Hygiene
Foodborne illness has been determined to be one of the major limitations to the advancement of wo... more Foodborne illness has been determined to be one of the major limitations to the advancement of world health. Bacterial pathogens among the leading causes of foodborne illness are Escherichia coli (E. coli), Campylobacter, Salmonella, and Listeria. The risk of these pathogens was investigated among gastroenteritis cases in the diverse population of the state of Qatar. Fecal samples from patients admitted to Hamad Medical Corporation (HMC) with complaints of gastroenteritis were screened for the targeted pathogens using a combination of bacterial enrichments and molecular detection. Salmonella was the most common pathogen (42.9%), followed by E. coli (35.3%), and Campylobacter (21.0%). C. jejuni was the most common species of Campylobacter (67.4%). The probability of detection of E. coli decreased with age. Meanwhile, both probabilities of detection of Campylobacter and Salmonella increased with age. Listeria monocytogenes was much less common among gastroenteritis cases compared to t...
Clinical Urine Tests [Working Title]
The relation between disease and urine was recognized by physicians since the earliest civilizati... more The relation between disease and urine was recognized by physicians since the earliest civilization BC. Urine is considered an ideal diagnostic specimen for its noninvasive and easy method of collection. Urinalysis encompasses a wide range of tests, which includes a variety of chemical tests, urine microscopy, bacterial cultures, and molecular tests. Importantly, urine tests can diagnose patients with antibiotic-resistant urinary tract infections (UTI), directly from urine and/or bacterial culture. This chapter summarizes the most common urine tests in the infectious disease field, with a special focus on diagnosing UTI and characterizing their antibiotic resistant. In addition to describing the advantages and limitation of these tests, the chapter explores the promising emerging technologies and methods in this field. This chapter is beneficial for scientists and healthcare workers in the field.
American Journal of Gastroenterology
Qatar Foundation Annual Research Conference Proceedings Volume 2014 Issue 1
Background and Introduction-According to the Food and Agricultural Organization that more than on... more Background and Introduction-According to the Food and Agricultural Organization that more than one-third of the population of the wor ld is affected each year by food-borne diseases caused by chemical and biological hazards. Foodsafet y has been identified as high priorit y in the Qatar National Food S ecurit y Master P lan. Campylobacter spp. are among the leading causes of foodborne illness and capable of triggering severe gastroenteritis with grave long-term sequelae and serious economic impact such as, Inflammator y Bowel Disease (IBD). The practice of drinking fresh camel milk, although is a tradition in Qatar, is increasing around the wor ld because of the perceived medicinal value for health in general, diabetes, autism, and allergies. In addition to the fact that camel milk is the c losest to human mother's milk, it contains high levels of antioxidants and iron. Being a fresh product it is exposed o foodborne pathogens inc luding Campylobacter spp. Understanding the pathway by which this hazard enter the food chain and pose risk to human will help in developing risk mitigation strategies. We carried out a study to assess the potential risk of illness from the consumption of camel milk contaminated with Campylobacter spp. in Qatar and identify critical inter vention points that would contribute to mitigating its associated risk. Methods-We used the quantitative risk assessment (QRA) methodolog y using a combination of deterministic and stochastic approaches to address the stated objectives. The QRA approach helps in identifying stages in the production system from farm-to-table that are likel y to play role in mitigating or exacerbating the risk of illness associated with the consumption of contaminated camel milk with this pathogen. Data on the probabilit y of either C. jejuni or C. coli in camel milk or in humans were obtained through repeat cross-sectional studies in these populations. Estimates of the adverse health effects were obtained using risk characterization which integrated data on hazard characterization and exposure assessment, inc luding dose-response model. A Monte Car lo S imulation of inputs in the model was performed using @Risk sof tware (Palisade S of tware, Newfield, NY, USA) and parameters were obtained using Latin Hypercube sampling. S ensitivit y anal yses were performed to capture the effect of uncer taint y and variabilit y of the different parameters used in the model on the predicted risk of illness. Results-O ur preliminar y anal yses showed that the probabilit y of illness for a healthy female from the consumption of camel milk contaminated with C. jejuni ranged from 5 x 10-3 to 24 x 10-2 depending on the amount of camel milk consumed. However, the risk for male is higher (13 x 10-3 to 30 x 10-2). The estimates of illness are three times higher for immune compromised females consumed fresh camel milk. We also evaluated the risk of illness for immune compromised males that consumed fresh camel milk and it was five-times higher in comparison to healthy men. The risk of illness due to the consumption of camel milk contaminated with either C. jejuni or C. coli could be significantl y reduced for either gender by increasing the efficac y of sterilizing the milk by boiling or pasteurization. Health and Biomedical
The Lancet Infectious Diseases
Background Invasive pneumococcal disease remains an important health priority owing to increasing... more Background Invasive pneumococcal disease remains an important health priority owing to increasing disease incidence caused by pneumococci expressing non-vaccine serotypes. We previously defined 621 Global Pneumococcal Sequence Clusters (GPSCs) by analysing 20 027 pneumococcal isolates collected worldwide and from previously published genomic data. In this study, we aimed to investigate the pneumococcal lineages behind the predominant serotypes, the mechanism of serotype replacement in disease, as well as the major pneumococcal lineages contributing to invasive pneumococcal disease in the post-vaccine era and their antibiotic resistant traits. Methods We whole-genome sequenced 3233 invasive pneumococcal disease isolates from laboratory-based surveillance programmes in Hong Kong (n=78), Israel (n=701), Malawi (n=226), South Africa (n=1351), The Gambia (n=203), and the USA (n=674). The genomes represented pneumococci from before and after pneumococcal conjugate vaccine (PCV) introductions and were from children younger than 3 years. We identified predominant serotypes by prevalence and their major contributing lineages in each country, and assessed any serotype replacement by comparing the incidence rate between the pre-PCV and PCV periods for Israel, South Africa, and the USA. We defined the status of a lineage as vaccine-type GPSC (≥50% 13-valent PCV [PCV13] serotypes) or non-vaccine-type GPSC (>50% non-PCV13 serotypes) on the basis of its initial serotype composition detected in the earliest vaccine period to measure their individual contribution toward serotype replacement in each country. Major pneumococcal lineages in the PCV period were identified by pooled incidence rate using a random effects model. Findings The five most prevalent serotypes in the PCV13 period varied between countries, with only serotypes 5, 12F, 15B/C, 19A, 33F, and 35B/D common to two or more countries. The five most prevalent serotypes in the PCV13 period varied between countries, with only serotypes 5, 12F, 15B/C, 19A, 33F, and 35B/D common to two or more countries. These serotypes were associated with more than one lineage, except for serotype 5 (GPSC8). Serotype replacement was mainly mediated by expansion of non-vaccine serotypes within vaccine-type GPSCs and, to a lesser extent, by increases in non-vaccine-type GPSCs. A globally spreading lineage, GPSC3, expressing invasive serotypes 8 in South Africa and 33F in the USA and Israel, was the most common lineage causing non-vaccine serotype invasive pneumococcal disease in the PCV13 period. We observed that same prevalent non-vaccine serotypes could be associated with distinctive lineages in different countries, which exhibited dissimilar antibiotic resistance profiles. In non-vaccine serotype isolates, we detected significant increases in the prevalence of resistance to penicillin (52 [21%] of 249 vs 169 [29%] of 575, p=0•0016) and erythromycin (three [1%] of 249 vs 65 [11%] of 575, p=0•0031) in the PCV13 period compared with the pre-PCV period. Interpretation Globally spreading lineages expressing invasive serotypes have an important role in serotype replacement, and emerging non-vaccine serotypes associated with different pneumococcal lineages in different countries might be explained by local antibiotic-selective pressures. Continued genomic surveillance of the dynamics of the pneumococcal population with increased geographical representation in the post-vaccine period will generate further knowledge for optimising future vaccine design. Funding Bill & Melinda Gates Foundation, Wellcome Sanger Institute, and the US Centers for Disease Control.
Global Journal of Health Science
BACKGROUND: Campylobacter and Salmonella are two of the major foodborne pathogens that contribute... more BACKGROUND: Campylobacter and Salmonella are two of the major foodborne pathogens that contribute to the burden of disease. The cytolethal distending toxin (CDT) has been identified as one of the virulence factors that may contribute to pathogenesis and gastroenteritis. The CDT is a trimeric subunit toxin produced by gram-negative bacteria that initiates cell-cycle arrest and causes affected cells to die by apoptosis. This study investigated the occurrence of CDT among Salmonella and Campylobacter spp. isolates recovered from animals along the food supply chain and from gastroenteritis cases in Qatar.METHODS: Samples were screened for the presence of the two pathogens using a combination of bacterial enrichment and molecular detection and positive samples were examined for the presence of CDT using a polymerase chain reaction (PCR) approach. RESULTS: C. jejuni and C. coli occurred at similar rates among non-human sources, whereas C. jejuni occurred at a higher rate compared to C. co...
Foodborne pathogens and disease, Jun 30, 2017
Pathogenic Escherichia coli has been listed among the most important bacteria associated with foo... more Pathogenic Escherichia coli has been listed among the most important bacteria associated with foodborne illnesses around the world. We investigated the genetic relatedness among Shiga toxin-producing E. coli (STEC) isolated along the animal food supply chain and from humans diagnosed with gastroenteritis in Qatar. Samples were collected from different sources along the food supply chain and from patients admitted to the hospital with complaints of gastroenteritis. All samples were screened for the presence of E. coli O157:H7 and non-O157 STEC using a combination of bacterial enrichment and molecular detection techniques. A proportional sampling approach was used to select positive samples from each source for further multilocus sequence typing (MLST) analysis. Seven housekeeping genes described for STEC were amplified by polymerase chain reaction, sequenced, and analyzed by MLST. Isolates were characterized by allele composition, sequence type (ST) and assessed for epidemiologic rel...
The Faseb Journal, Apr 1, 2010
BMC Infectious Diseases, 2016
Background: The World Health Organization estimates that about 3.5 billion people worldwide are a... more Background: The World Health Organization estimates that about 3.5 billion people worldwide are affected by intestinal parasitic infections. Reports have already emphasized the role of immigrants in outbreaks of parasitic diseases in industrialized countries. With the mass influx of immigrants to Qatar, patent intestinal parasitic infections have been observed. Herein, the prevalence of intestinal protozoan infections was analysed in 29,286 records of subjects referred for stool examination at the Hamad Medical Corporation over the course of a decade (2005 to 2014, inclusive). Results: Overall prevalence of combined protozoan infections was 5.93 % but there were significant temporal trends, age and sex effects and those arising from the region of origin of the subjects. The most common protozoan was Blastocystis hominis (overall prevalence 3.45 %). Giardia duodenalis, Chilomastix mesnili, Entamoeba coli, Entamoeba hartmanni, Endolimax nana, Iodamoeba butschlii, Entamoeba histolytica/dispar, Cryptosporidium sp. and a single case of Isospora were also detected. The prevalence of combined protozoan infections, G. duodenalis and the non-pathogenic amoebae all declined significantly across the decade. That of B. hominis varied between years but showed no directional trend across years and there was no evidence that prevalence of E. histolyitica/ dispar changed significantly. Protozoan infections were observed among all regional groups, but prevalence was higher among subjects from the Arabian Peninsula, Africa and Asia compared to those from the Eastern Mediterranean and Qatar. Prevalence was higher among male subjects in all cases, but age-prevalence profiles differed between the taxa. Conclusion: These results offer optimism that prevalence will continue to decline in the years ahead.
International journal of health sciences, 2016
To assess the risk of gastroenteritis associated with bacterial foodborne pathogens and identify ... more To assess the risk of gastroenteritis associated with bacterial foodborne pathogens and identify associated factors in a highly diverse population. A series of case-control studies were carried out to address the stated objective. The study population consisted of individuals who were admitted to the Hamad Medical Corporation hospitals and stool analysis indicated positive findings to Campylobacter spp., Escherichia coli, or Salmonella spp. between the period of August 2009 and December 2012. Cases were defined based on positive stool analysis to any of the previously mentioned organisms. Control group was similar to case group but negative in stool analysis to the particular pathogen under study. Association between demographic characteristics and likelihood of pathogen infection were investigated using logistic regression analysis. A total of 423 individuals diagnosed with these bacterial pathogens were randomly enrolled in the study. The majority of cases were infected by E.coli....
Parasites & Vectors, 2016
Background: Travel and migration from developing regions, where tropical diseases are common, to ... more Background: Travel and migration from developing regions, where tropical diseases are common, to more developed industrialised nations can contribute to the introduction and subsequent spread of infections. With its rapidly expanding economy, Qatar has attracted vast numbers of immigrant workers in the last two decades, often from countries with poor socioeconomic levels. Many used to arrive with patent intestinal parasitic infections. Methods: We analysed the prevalence of helminth infections in a dataset of 29,286 records of subjects referred for stool examination at the Hamad Medical Corporation over the course of a decade (2005 to 2014, inclusive). Results: Overall prevalence of combined helminth infections was low (1.86 %) but there were significant temporal trends, age and sex effects and those arising from the region of origin of the subjects. The most common helminths were hookworms (overall prevalence 1.22 %), which accounted for 70.1 % of cases, and therefore patterns for combined helminth infections were largely driven by hookworms. In both cases, and also in Trichuris trichiura and Ascaris lumbricoides, prevalence peaked in 2008, since when prevalence has been steadily falling. Helminth infections were largely concentrated among subjects from five Asian countries (Nepal, Bangladesh, Sri Lanka, India and Pakistan), and there was a highly biased prevalence in favour of male subjects in all cases. Prevalence of all three nematodes peaked in age class 7 (mean age 25.5 years, range = 20-29) and there were significant interactions between region of origin, sex of subjects and prevalence of hookworms. Conclusion: These results offer optimism that prevalence will continue to decline in the years ahead, especially if control is targeted at those most at risk of carrying infections.
Journal of infection and public health, Jan 26, 2015
Salmonella enterica is one of the most commonly reported causes of bacterial foodborne illness ar... more Salmonella enterica is one of the most commonly reported causes of bacterial foodborne illness around the world. Understanding the sources of this pathogen and the associated factors that exacerbate its risk to humans will help in developing risk mitigation strategies. The genetic relatedness among Salmonella isolates recovered from human gastroenteritis cases and food animals in Qatar were investigated in the hope of shedding light on these sources, their possible transmission routes, and any associated factors. A repeat cross-sectional study was conducted in which the samples and associated data were collected from both populations (gastroenteritis cases and animals). Salmonella isolates were initially analyzed using multi-locus sequence typing (MLST) to investigate the genetic diversity and clonality. The relatedness among the isolates was assessed using the minimum spanning tree (MST). Twenty-seven different sequence types (STs) were identified in this study; among them, seven w...
Indian journal of gastroenterology : official journal of the Indian Society of Gastroenterology, Jan 5, 2015
Despite 30 years of its discovery, the ideal therapeutic regimen against Helicobacter pylori is s... more Despite 30 years of its discovery, the ideal therapeutic regimen against Helicobacter pylori is still evasive. Clarithromycin-based standard triple therapy which has been considered the first line empirical therapy has been failing in many parts of the world, due to rising resistance against Clarithromycin, forcing the use of alternate regimens. In this context, we studied the local antibiotic resistance patterns against H. pylori and its impact on standard triple therapy in our region. All patients undergoing diagnostic upper endoscopy during the study period and detected to be positive for rapid urease test (RUT) underwent cultures of gastric mucosal specimens and had their antibiotic resistance patterns mapped out. Standard triple therapy was administered to those tested positive for H. pylori by RUT and eradication rates checked by urea breath test 4 weeks after the completion of treatment. Eradication rates with Clarithromycin-based standard triple therapy were suboptimal with ...
BMC Microbiology, 2015
Brucellosis is one of the most common zoonotic disease affecting humans and animals and is endemi... more Brucellosis is one of the most common zoonotic disease affecting humans and animals and is endemic in many parts of the world including the Gulf Cooperation Council region (GCC). The aim of this study was to identify the species and determine the antimicrobial susceptibility pattern of Brucella strains isolated from clinical specimens, from Qatar. We evaluated 231 Brucella isolates. All isolates were identified as B. melitensis. All the isolates were susceptible to doxycycline, tetracycline, streptomycin, gentamicin, trimethoprim / sulfamethoxazole and ciprofloxacin except rifampicin, where 48 % of the strains showed elevated MICs (>1 mg/L). The rifampicin-resistance related hotspots within the rpoB gene were amplified and sequenced using PCR and no rpoB mutations were found in strains with rifampicin MICs of >2 mg/L. This study identified B. melitensis as the etiological agent of brucellosis in Qatar. No resistant isolates were detected among conventionally used antimicrobial agents.
BMC infectious diseases, Jan 3, 2015
Peritoneal Dialysis International, 2010
Background The micro-organisms involved in continuous ambulatory peritoneal dialysis (CAPD) perit... more Background The micro-organisms involved in continuous ambulatory peritoneal dialysis (CAPD) peritonitis are usually gram-positive cocci of cutaneous origin. Campylobacter species are rarely implicated as a cause of CAPD peritonitis. Methods A retrospective review of 100 consecutive episodes of peritonitis was carried out in patients undergoing CAPD or automated PD in our hospital from June 2004 to December 2007. Collection of dialysate and microbial examination was done according to ISPD guidelines. Identification of the organism was made on the basis of Gram smear morphology, positive oxidase test, and biochemical reactions using API Campi (BioMérieux, Marcy l'Étoile, France). Susceptibility testing was performed using E-test (AB Biodisc, Solna, Sweden) and confirmation was done by molecular techniques. Results The causative organisms in 23 of these episodes were gram-negative bacteria, 3 of which were identified as Campylobacter species using special culture techniques. The cl...
PLOS ONE, 2015
Campylobacter infections are a major cause of diarrhoea worldwide and two of the antimicrobials u... more Campylobacter infections are a major cause of diarrhoea worldwide and two of the antimicrobials used for their control (erythromycin and ciprofloxacin) have been losing efficacy in recent years. In a sample of 174 genotyped isolates from the stools of patients with severe diarrhoea in Qatar, collected between 2005 and 2012, 63.2% showed resistance to ciprofloxacin, 8.6% to erythromycin, 0.57% to chloramphenicol and all were sensitive to gentamycin. While 33.9% of isolates were sensitive to all four antimicrobials, 59.8% were resistant to at least one, 6.3% were resistant to two and none showed resistance to three antimicrobials. There was no host sex-or age-dependence among isolates resistant to ciprofloxacin and erythromycin and no significant variation was found with the region of origin of the patients. All isolates were screened for the presence of 3 virulence factors (ciaB, cadF and cdtB) and two stress-response factors (htrB and clpP), all of which were present in more than 50% of the isolates. Host sex-, age-and region of origin-dependent variations in prevalence were found for some of these factors. Data analysis for the combination of virulence factors and their effect on antimicrobial resistance indicated that the prevalence of resistance to both erythromycin and ciprofloxacin was higher in isolates harbouring ciaB but not clpP. Prevalence of resistance to ciprofloxacin was similar in clpP positive and negative isolates also possessing htrB, while for htrB-negative isolates prevalence was higher in the absence of clpP. These results are discussed and their implications are highlighted.
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Papers by Sanjay Doiphode