Marawan Abu-madi | Qatar University (original) (raw)

Papers by Marawan Abu-madi

Research paper thumbnail of Clinical Practicum Assessment for Biomedical Science Program from Graduates’ Perspective

International Journal of Environmental Research and Public Health

The clinical practicum for biomedical science students aims to provide graduates with the knowled... more The clinical practicum for biomedical science students aims to provide graduates with the knowledge and skills required to work in diagnostic laboratory settings. This study examines graduates’ perspectives on content, teachers and clinical training and their satisfaction rates based on the skills gained during training. The study was conducted on females who graduated from Qatar University between 2015 and 2020. We used a previously validated questionnaire called CPAT-QU. Telephonic interviews were conducted and were analyzed using SPSS. The results showed a high satisfaction rate, of 80%, for the content and organization of the clinical training. The participants’ main concerns included the evaluation criteria, as 8.7% were not satisfied. The students suggested increasing the length of the training in order to obtain experience that was more practical. The students’ satisfaction with the teachers was 70% in terms of their attitude, command of knowledge and ability to convey knowle...

Research paper thumbnail of Prevalence of the virulence factor <i>ciaB</i> (A) and <i>htrB</i> (B) among male and female subjects in each of the age classes (A) and from each of the five regions of origin used for analysis (B)

<p>The sample sizes in A were as follows: for the 104 male subjects, 22, 24, 21, 26 and 11,... more <p>The sample sizes in A were as follows: for the 104 male subjects, 22, 24, 21, 26 and 11, and for the 70 female subjects 12, 20, 10, 17 and 11 for age classes 1–5 respectively in both cases. For the age span and average age of each age class see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0119268#sec002&quot; target="_blank">Materials and Methods</a>. The sample sizes in B were as follows: for the 104 male subjects, 46, 18, 26, 11 and 3, and for the 70 female subjects 26, 15, 16, 10 and 3 for the five regions of origin (Qatar, Arabian Peninsula, Asia, Africa and elsewhere) respectively in both cases. For further details of countries of origin in each region see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0119268#sec002&quot; target="_blank">Materials and Methods</a>.</p

Research paper thumbnail of Development and Validation of a Clinical Practicum Assessment Tool for the NAACLS-Accredited Biomedical Science Program

International Journal of Environmental Research and Public Health

Student perspectives on their final year clinical placements in biomedical sciences at Qatar Univ... more Student perspectives on their final year clinical placements in biomedical sciences at Qatar University are assessed using the clinical practicum assessment tool (CPAT), which was developed in-house following accreditation body requirements. The tool, which we call the CPAT-Qatar University (CPAT-QU), covers the three clinical practicum domains: practicum content, preceptors, and competencies. Here, we validate this tool. The CPAT-QU has 27 Likert-scale questions and free-text open questions. CPAT-QU readability was calculated using the Flesch–Kincaid Reading Ease (FKRE) instrument. Content validity was assessed using the average and universal average scale-level content validity indices (S-CVI/Average and S-CVI/UA). For construct validity, 50 employed graduates who had completed the practicum were consented for study participation, and the validity was calculated by a principal component analysis (PCA). Reliability was analyzed by Cronbach’s alpha. The S-CVI/Average and S-CVI/UA we...

Research paper thumbnail of The Genetic Control of the Rheumatic Heart: Closing the Genotype-Phenotype Gap

Frontiers in Medicine, 2021

Rheumatic heart disease (RHD) is a heritable inflammatory condition characterized by carditis, ar... more Rheumatic heart disease (RHD) is a heritable inflammatory condition characterized by carditis, arthritis, and systemic disease. Although remaining neglected, the last 3 years has seen some promising advances in RHD research. Whilst it is clear that RHD can be triggered by recurrent group A streptococcal infections, the mechanisms driving clinical progression are still poorly understood. This review summarizes our current understanding of the genetics implicated in this process and the genetic determinants that predispose some people to RHD. The evidence demonstrating the importance of individual cell types and cellular states in delineating causal genetic variants is discussed, highlighting phenotype/genotype correlations where possible. Genetic fine mapping and functional studies in extreme phenotypes, together with large-scale omics studies including genomics, transcriptomics, epigenomics, and metabolomics, are expected to provide new information not only on RHD but also on the me...

Research paper thumbnail of The distribution of Blastocystis subtypes in isolates from Qatar

Parasites & Vectors, 2015

Background: Blastocystis is a common single-celled intestinal parasite of humans and other animal... more Background: Blastocystis is a common single-celled intestinal parasite of humans and other animals comprising at least 17 genetically distinct small subunit ribosomal RNA lineages (subtypes (STs)), nine of which have been found in humans. The geographic distribution of Blastocystis subtypes is variable, but the subtypes present in Qatar are at present unknown. Methods: Stool samples were collected from randomly selected, apparently healthy subjects arriving in Qatar for the first time. Blastocystis subtypes were determined by sequencing of the small subunit rRNA gene (SSU rDNA) PCR products. Phylogenetic analyses were done using Maximum Composite Likelihood method. Results: 71.1 % of samples were positive for Blastocystis infection based on PCR-detection methodology compared to only 6.9 % by microscopy. Prevalence of Blastocystis did not differ between the sexes nor between age classes. However, there was a regional difference in prevalence with subjects arriving from Africa showing the highest (87.6 %), those from Western Asia intermediate (68.6 %) and from Eastern Asia the lowest prevalence (67.6 %). Genetic analysis detected only three STs. ST3 was the most common (69.3 %) and ST2 was the rarest (3.5 %), while ST1 had a prevalence of 27.2 %. ST2 showed a regional variation, being absent from the 64 Western Asian Blastocystis-positive subjects. Both ST1 and ST3 showed significant differences in prevalence between the sexes. Conclusions: This is the first report exploring the distribution of Blastocystis subtypes in our region. We recommend that stool screening via microscopy for the presence of Blastocystis should be abandoned since it is extremely insensitive. In future, the prevalence of Blastocystis infections should be based on PCR methodology and we predict that in the years ahead diagnostic PCR will become the tool of choice. More work is needed to identify the full range of Blastocystis subtypes that circulate in our region.

Research paper thumbnail of Analysis of Resistance to Antimicrobials and Presence of Virulence/Stress Response Genes in Campylobacter Isolates from Patients with Severe Diarrhoea

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.

Research paper thumbnail of Advances in vaccination against avian pathogenic Escherichia coli respiratory disease: Potentials and limitations

Veterinary Microbiology, 2014

Avian pathogenic Escherichia coli (APEC) is one of the most economically devastating pathogens af... more Avian pathogenic Escherichia coli (APEC) is one of the most economically devastating pathogens affecting the poultry industry. This group of extra-intestinal E. coli causes a variety of clinical conditions including airsacculitis and cellulitis. The economic impact of APEC is mainly due to mortality, slower growth rates, and carcass downgrading. In commercial broiler operations, APEC infections are controlled indirectly by vaccination against other respiratory diseases and minimizing stress conditions, and directly by administration of antimicrobial agents to suppress the infection in already infected flocks. The fact that most APEC strains possess some common virulence factors suggests that an effective vaccine against APEC is a viable option. The most important virulence factors that have been investigated over the years include type I and P fimbriae, aerobactin iron-acquisition system, and serum resistance traits. Despite the potential for developing an efficacious vaccine to combat this economically important poultry disease, several obstacles hinder such efforts. Those obstacles include the cost, vaccine delivery method and timing of vaccination as the birds should be immune to APEC by 21 days of age. Herein, we review the various attempts to develop an effective vaccine against the respiratory form of APEC diseases in poultry. We also discuss in-depth the potentials and limitations of such vaccines.

Research paper thumbnail of Socio-demographic influences on the prevalence of enteric helminth and protozoan infections in newly arrived migrant workers in Qatar

Background Intestinal parasitosis is a major concern for public health, especially in children fr... more Background Intestinal parasitosis is a major concern for public health, especially in children from middle and low-income populations of tropical and subtropical areas. In this study, we explored the environmental and socio-demographic characteristics of immigrants in Doha Qatar, that might explain the persistence of the parasites that they harbor.Methodology This cross-sectional survey was conducted among 2,486 newly arrived expatriates and those who visited Qatar previously during the period 2012-2014. Through questionnaires and census data, we characterised the socio-demographics conditions at an individual, family and neighborhood levels.Results Combined protozoan infections were significantly associated with immigrants arriving in Doha for the first time. In univariate loglinear statistical models fitted in phase 1 of the analysis significant associations were observed between the prevalence of combined protozoan infections and personal and familial factors that included religi...

Research paper thumbnail of Assessing the burden of intestinal parasites affecting newly arrived immigrants in Qatar

Parasites & Vectors, 2016

Background: In the last decades, the enormous influx of immigrants to industrialized countries ha... more Background: In the last decades, the enormous influx of immigrants to industrialized countries has led to outbreaks of parasitic diseases, with enteric infections being amongst the most frequently encountered. In its strategy to control such infection, Qatar has established the Pre-Employment Certificate (PEC) program which requires medical inspection before arrival in Qatar and which is mandatory for immigrant workers travelling to the country. To assess the reliability of the PEC, we conducted a survey of intestinal parasites, based on examination of stool samples provided by immigrant workers (n = 2,486) recently arrived in Qatar. Results: Overall prevalence of helminths was 7.0% and that of protozoa was 11.7%. Prevalence of combined helminths was highest among the western Asians and the highest prevalence of combined protozoan parasites was among workers from North to Saharan Africa. Analysis of temporal changes showed an increasing trend of protozoan infections over the investigated 3 years. A major contribution to this temporal change in prevalence came from Blastocystis hominis as well as from other protozoan species: Giardia duodenalis and Endolimax nana. Analysis of the temporal trend in species richness of the protozoan species showed a significant increase in the mean number of species harboured per subject across this period. Conclusion: The increase of protozoan infections over recent years raises some concerns. It suggests that screening protocols for applicants for visas/work permits needs to be revised giving more careful attention to the intestinal protozoan infections that potential immigrants may harbor.

Research paper thumbnail of Index of Contents (Volume 72)

Research paper thumbnail of 99 Performance of MALDI-TOF mass spectrometry method for identification of bacteria commonly isolated from cystic fibrosis patients

Research paper thumbnail of Comparison of intestinal parasitic infection in newly arrived and resident workers in Qatar

BackgroundThe rapid growth of Qatar in the last two decades has been associated with an enormous ... more BackgroundThe rapid growth of Qatar in the last two decades has been associated with an enormous expansion of building programs in its cities and in the provision of new service industries. This in turn has attracted a large influx of immigrant workers seeking employment in jobs associated with food handling, domestic service and the building industry. Many of these immigrants come from countries in the tropics and subtropics where intestinal parasitic infections are common.MethodsWe analyzed intestinal parasitic infections recorded in 2008 among immigrant and long-term resident workers in Doha city, Qatar (n = 1538). Stool examinations were carried out at the Hamad Medical Corporation and at the Medical Commission in Doha using standard procedures.ResultsOverall, 21.5% of subjects were infected with at least one of the species recorded (8 helminth and 4 protozoan species; the highest prevalence was for hookworms = 8.3%) and there were strong regional effects on prevalence of helmin...

Research paper thumbnail of Serum Uric Acid Level Is Positively Associated With Higher Bone Mineral Density at Multiple Skeletal Sites Among Healthy Qataris

Frontiers in Endocrinology

BackgroundOxidative stress has been implicated as a fundamental mechanism in the decline of bone ... more BackgroundOxidative stress has been implicated as a fundamental mechanism in the decline of bone mass. Although serum uric acid (SUA) has potent antioxidant properties, the findings of many epidemiological and experimental studies couldn’t draw a clear conclusion on the relation between SUA and bone health. We aim to investigate the association between SUA and bone mineral density (BMD) at different skeletal sites among healthy Qataris.MethodologyA cross-sectional analysis including total-body and site-specific bone mineral density scores and other serological markers of 2981 healthy Qatari adults (36.4 ± 11.1 years) from the Qatar biobank database was conducted. The study participants were divided into quartiles based on the level of SUA, and the BMD was measured using dual-energy X-ray absorptiometry (DXA). Multiple regression analyses were applied to investigate the association between SUA and BMD adjusting for multiple confounding factors.ResultsHigh levels of SUA were significa...

Research paper thumbnail of Genetic Diversity and Prevalence of Giardia duodenalis in Qatar

Frontiers in Cellular and Infection Microbiology

BackgroundGiardia duodenalis is a common human intestinal parasite worldwide, and the causative a... more BackgroundGiardia duodenalis is a common human intestinal parasite worldwide, and the causative agent of diarrhea, with the severity of disease ranging from asymptomatic to intense and debilitating infection. G. duodenalis is known to consist of eight genetically distinct assemblages, named from A to H. No data available on the genotypes and genetic diversity of G. duodenalis circulating in Qatar.MethodsWe genotyped 54 human Giardia isolates, collected from asymptomatic immigrants in Qatar, using a multilocus genotyping (MLGs) tool. We also investigated relationships between the subjects’ genotypes and their demographic data.ResultsGenomic DNA from 54 isolates were tested by PCR and sequence analysis at three loci: glutamate dehydrogenase (gdh), β-giardin (bg) and triose phosphate (tpi)). Assemblage A was identified in nine (16.67%), assemblage B in thirty (55.55%), and a mixture of assemblages A+B in fifteen (27.78%) isolates. All assemblage A isolates, genotyped in different loci,...

Research paper thumbnail of COVID-19 Vaccine Hesitancy in a Representative Education Sector Population in Qatar

Vaccines

Even though vaccination programs have now started in earnest across the globe and in Qatar, vacci... more Even though vaccination programs have now started in earnest across the globe and in Qatar, vaccine hesitancy remains a barrier to effectively tackling the pandemic. Many factors influence willingness to take vaccines including safety, efficacy, and side effects. Given their proximity to research and education, university students and employees represent an interesting cohort in which to investigate vaccine hesitancy. The aim of this study was to assess the attitudes of Qatar University employees and students towards the COVID-19 vaccine. In total, 231 employees and 231 students participated in an online cross-sectional study in February 2021. Of the sample, 62.6% were willing to take a vaccine against COVID-19. Participants with or taking postgraduate degrees were more willing to take the vaccine compared to participants with or taking a diploma or bachelor’s degree (p < 0.001). Males had a higher rate of vaccine acceptance (p < 0.001). In the group that regarded flu vaccinat...

Research paper thumbnail of A Whole-Genome Sequencing Association Study of Low Bone Mineral Density Identifies New Susceptibility Loci in the Phase I Qatar Biobank Cohort

Journal of Personalized Medicine

Bone density disorders are characterized by a reduction in bone mass density and strength, which ... more Bone density disorders are characterized by a reduction in bone mass density and strength, which lead to an increase in the susceptibility to sudden and unexpected fractures. Despite the serious consequences of low bone mineral density (BMD) and its significant impact on human health, most affected individuals may not know that they have the disease because it is asymptomatic. Therefore, understanding the genetic basis of low BMD and osteoporosis is essential to fully elucidate its pathobiology and devise preventative or therapeutic approaches. Here we sequenced the whole genomes of 3000 individuals from the Qatar Biobank and conducted genome-wide association analyses to identify genetic risk factors associated with low BMD in the Qatari population. Fifteen variants were significantly associated with total body BMD (p < 5 × 10−8). Of these, five variants had previously been reported by and were directionally consistent with previous genome-wide association study data. Ten variant...

Research paper thumbnail of The Role of Soluble Uric Acid in Modulating Autophagy Flux and Inflammasome Activation during Bacterial Infection in Macrophages

Biomedicines

Autophagy is a homeostatic process that regulates and recycles intracellular structures and is a ... more Autophagy is a homeostatic process that regulates and recycles intracellular structures and is a host defense mechanism that facilitates bacterial clearance. Uric acid in plasma is a major antioxidant but in certain conditions acts as an inflammatory danger signal. The aim of this study is to investigate the effect of soluble uric acid on autophagy and the inflammatory responses in macrophages during bacterial infection. Herein, we employed murine RAW264.7 macrophages that express uricase enzyme and human THP-1 cells that are uricase-deficient. Three different strains of Staphylococcus aureus and two different strains of Klebsiella pneumoniae were used to infect macrophages in presence and absence of soluble uric acid. We found that soluble uric acid enhanced autophagy flux in infected macrophages. We observed that IL-1β increased during bacterial infection but decreased when macrophages were co-stimulated with bacteria and uric acid. In contrast to IL-1β, soluble uric acid did not ...

Research paper thumbnail of Cryptosporidium spp., prevalence, molecular characterisation and socio-demographic risk factors among immigrants in Qatar

PLOS Neglected Tropical Diseases

Background The World Health Organization WHO has estimated that in developed countries, up to 30%... more Background The World Health Organization WHO has estimated that in developed countries, up to 30% of the population may suffer from foodborne diseases each year, and that in developing countries up to 2 million deaths per annum can be attributed to cryptosporidiosis. Reports have already emphasized the role of immigrants in outbreaks of parasitic diseases especially those working in food processing industries. Methodology/Principal findings Herein we assessed Cryptosporidium spp. infections among immigrants in Qatar with a special focus on food handlers and housemaids. The overall prevalence of Cryptosporidium spp. by q-PCR among 839 asymptomatic subjects was 4.5%. Based on the Gp60 gene, the majority of isolates were identified as C. parvum subtype IIdA20G1b. The positive sample for C. hominis was subtyped as IeA12G3T3. Seven mixed infections were also identified (four C. parvum + C. hominis, and three C. parvum + C. meleagridis). The prevalence of Cryptosporidium spp. did not differ significantly between the sexes or age classes but varied significantly between subjects affiliated to different religions with the lowest prevalence among the Muslims. Multifactorial analysis retained also marked significance with education, income, and a house contents index. Conclusions/Significance Our results contribute to a better understanding of the epidemiology of cryptosporidiosis and the risk factors associated with the likelihood of carrying this infection among immigrant workers from developing countries.

Research paper thumbnail of Seroprevalence of Toxoplasma Gondii Among Stray Cats in Qatar

Qatar Foundation Annual Research Conference Proceedings Volume 2016 Issue 1

Research paper thumbnail of Molecular Analysis of the Enteric Protozoa Associated with Acute Diarrhea in Hospitalized Children

Frontiers in Cellular and Infection Microbiology

Pediatric diarrhea is a common cause of death among children under 5 years of age. In the current... more Pediatric diarrhea is a common cause of death among children under 5 years of age. In the current study, we investigated the frequency of intestinal parasites among 580 pediatric patients with chronic diarrhea. Parasitic protozoa (all species combined) were detected by molecular tools in 22.9% of the children and the most common parasite was Cryptosporidium spp. (15.1%). Blastocystis hominis was detected in 4.7%, Dientamoeba fragilis in 4%, Giardia duodenalis in 1.7%, and Entamoeba histolytica in 0.17%. Protozoan infections were observed among all regional groups, but prevalence was highest among Qatari subjects and during the winter season. Typing of Cryptosporidium spp. revealed a predominance of Cryptosporidium parvum in 92% of cases with mostly the IIdA20G1 subtype. Subtypes IIdA19G2, IIdA18G2, IIdA18G1, IIdA17G1, IIdA16G1, and IIdA14G1 were also detected. For Cryptosporidium hominis, IbA10G2 and IbA9G3 subtypes were identified. This study provides supplementary information for implementing prevention and control strategies to reduce the burden of these pediatric protozoan infections. Further analyses are required to better understand the local epidemiology and transmission of Cryptosporidium spp. in Qatar.

Research paper thumbnail of Clinical Practicum Assessment for Biomedical Science Program from Graduates’ Perspective

International Journal of Environmental Research and Public Health

The clinical practicum for biomedical science students aims to provide graduates with the knowled... more The clinical practicum for biomedical science students aims to provide graduates with the knowledge and skills required to work in diagnostic laboratory settings. This study examines graduates’ perspectives on content, teachers and clinical training and their satisfaction rates based on the skills gained during training. The study was conducted on females who graduated from Qatar University between 2015 and 2020. We used a previously validated questionnaire called CPAT-QU. Telephonic interviews were conducted and were analyzed using SPSS. The results showed a high satisfaction rate, of 80%, for the content and organization of the clinical training. The participants’ main concerns included the evaluation criteria, as 8.7% were not satisfied. The students suggested increasing the length of the training in order to obtain experience that was more practical. The students’ satisfaction with the teachers was 70% in terms of their attitude, command of knowledge and ability to convey knowle...

Research paper thumbnail of Prevalence of the virulence factor <i>ciaB</i> (A) and <i>htrB</i> (B) among male and female subjects in each of the age classes (A) and from each of the five regions of origin used for analysis (B)

<p>The sample sizes in A were as follows: for the 104 male subjects, 22, 24, 21, 26 and 11,... more <p>The sample sizes in A were as follows: for the 104 male subjects, 22, 24, 21, 26 and 11, and for the 70 female subjects 12, 20, 10, 17 and 11 for age classes 1–5 respectively in both cases. For the age span and average age of each age class see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0119268#sec002&quot; target="_blank">Materials and Methods</a>. The sample sizes in B were as follows: for the 104 male subjects, 46, 18, 26, 11 and 3, and for the 70 female subjects 26, 15, 16, 10 and 3 for the five regions of origin (Qatar, Arabian Peninsula, Asia, Africa and elsewhere) respectively in both cases. For further details of countries of origin in each region see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0119268#sec002&quot; target="_blank">Materials and Methods</a>.</p

Research paper thumbnail of Development and Validation of a Clinical Practicum Assessment Tool for the NAACLS-Accredited Biomedical Science Program

International Journal of Environmental Research and Public Health

Student perspectives on their final year clinical placements in biomedical sciences at Qatar Univ... more Student perspectives on their final year clinical placements in biomedical sciences at Qatar University are assessed using the clinical practicum assessment tool (CPAT), which was developed in-house following accreditation body requirements. The tool, which we call the CPAT-Qatar University (CPAT-QU), covers the three clinical practicum domains: practicum content, preceptors, and competencies. Here, we validate this tool. The CPAT-QU has 27 Likert-scale questions and free-text open questions. CPAT-QU readability was calculated using the Flesch–Kincaid Reading Ease (FKRE) instrument. Content validity was assessed using the average and universal average scale-level content validity indices (S-CVI/Average and S-CVI/UA). For construct validity, 50 employed graduates who had completed the practicum were consented for study participation, and the validity was calculated by a principal component analysis (PCA). Reliability was analyzed by Cronbach’s alpha. The S-CVI/Average and S-CVI/UA we...

Research paper thumbnail of The Genetic Control of the Rheumatic Heart: Closing the Genotype-Phenotype Gap

Frontiers in Medicine, 2021

Rheumatic heart disease (RHD) is a heritable inflammatory condition characterized by carditis, ar... more Rheumatic heart disease (RHD) is a heritable inflammatory condition characterized by carditis, arthritis, and systemic disease. Although remaining neglected, the last 3 years has seen some promising advances in RHD research. Whilst it is clear that RHD can be triggered by recurrent group A streptococcal infections, the mechanisms driving clinical progression are still poorly understood. This review summarizes our current understanding of the genetics implicated in this process and the genetic determinants that predispose some people to RHD. The evidence demonstrating the importance of individual cell types and cellular states in delineating causal genetic variants is discussed, highlighting phenotype/genotype correlations where possible. Genetic fine mapping and functional studies in extreme phenotypes, together with large-scale omics studies including genomics, transcriptomics, epigenomics, and metabolomics, are expected to provide new information not only on RHD but also on the me...

Research paper thumbnail of The distribution of Blastocystis subtypes in isolates from Qatar

Parasites & Vectors, 2015

Background: Blastocystis is a common single-celled intestinal parasite of humans and other animal... more Background: Blastocystis is a common single-celled intestinal parasite of humans and other animals comprising at least 17 genetically distinct small subunit ribosomal RNA lineages (subtypes (STs)), nine of which have been found in humans. The geographic distribution of Blastocystis subtypes is variable, but the subtypes present in Qatar are at present unknown. Methods: Stool samples were collected from randomly selected, apparently healthy subjects arriving in Qatar for the first time. Blastocystis subtypes were determined by sequencing of the small subunit rRNA gene (SSU rDNA) PCR products. Phylogenetic analyses were done using Maximum Composite Likelihood method. Results: 71.1 % of samples were positive for Blastocystis infection based on PCR-detection methodology compared to only 6.9 % by microscopy. Prevalence of Blastocystis did not differ between the sexes nor between age classes. However, there was a regional difference in prevalence with subjects arriving from Africa showing the highest (87.6 %), those from Western Asia intermediate (68.6 %) and from Eastern Asia the lowest prevalence (67.6 %). Genetic analysis detected only three STs. ST3 was the most common (69.3 %) and ST2 was the rarest (3.5 %), while ST1 had a prevalence of 27.2 %. ST2 showed a regional variation, being absent from the 64 Western Asian Blastocystis-positive subjects. Both ST1 and ST3 showed significant differences in prevalence between the sexes. Conclusions: This is the first report exploring the distribution of Blastocystis subtypes in our region. We recommend that stool screening via microscopy for the presence of Blastocystis should be abandoned since it is extremely insensitive. In future, the prevalence of Blastocystis infections should be based on PCR methodology and we predict that in the years ahead diagnostic PCR will become the tool of choice. More work is needed to identify the full range of Blastocystis subtypes that circulate in our region.

Research paper thumbnail of Analysis of Resistance to Antimicrobials and Presence of Virulence/Stress Response Genes in Campylobacter Isolates from Patients with Severe Diarrhoea

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.

Research paper thumbnail of Advances in vaccination against avian pathogenic Escherichia coli respiratory disease: Potentials and limitations

Veterinary Microbiology, 2014

Avian pathogenic Escherichia coli (APEC) is one of the most economically devastating pathogens af... more Avian pathogenic Escherichia coli (APEC) is one of the most economically devastating pathogens affecting the poultry industry. This group of extra-intestinal E. coli causes a variety of clinical conditions including airsacculitis and cellulitis. The economic impact of APEC is mainly due to mortality, slower growth rates, and carcass downgrading. In commercial broiler operations, APEC infections are controlled indirectly by vaccination against other respiratory diseases and minimizing stress conditions, and directly by administration of antimicrobial agents to suppress the infection in already infected flocks. The fact that most APEC strains possess some common virulence factors suggests that an effective vaccine against APEC is a viable option. The most important virulence factors that have been investigated over the years include type I and P fimbriae, aerobactin iron-acquisition system, and serum resistance traits. Despite the potential for developing an efficacious vaccine to combat this economically important poultry disease, several obstacles hinder such efforts. Those obstacles include the cost, vaccine delivery method and timing of vaccination as the birds should be immune to APEC by 21 days of age. Herein, we review the various attempts to develop an effective vaccine against the respiratory form of APEC diseases in poultry. We also discuss in-depth the potentials and limitations of such vaccines.

Research paper thumbnail of Socio-demographic influences on the prevalence of enteric helminth and protozoan infections in newly arrived migrant workers in Qatar

Background Intestinal parasitosis is a major concern for public health, especially in children fr... more Background Intestinal parasitosis is a major concern for public health, especially in children from middle and low-income populations of tropical and subtropical areas. In this study, we explored the environmental and socio-demographic characteristics of immigrants in Doha Qatar, that might explain the persistence of the parasites that they harbor.Methodology This cross-sectional survey was conducted among 2,486 newly arrived expatriates and those who visited Qatar previously during the period 2012-2014. Through questionnaires and census data, we characterised the socio-demographics conditions at an individual, family and neighborhood levels.Results Combined protozoan infections were significantly associated with immigrants arriving in Doha for the first time. In univariate loglinear statistical models fitted in phase 1 of the analysis significant associations were observed between the prevalence of combined protozoan infections and personal and familial factors that included religi...

Research paper thumbnail of Assessing the burden of intestinal parasites affecting newly arrived immigrants in Qatar

Parasites & Vectors, 2016

Background: In the last decades, the enormous influx of immigrants to industrialized countries ha... more Background: In the last decades, the enormous influx of immigrants to industrialized countries has led to outbreaks of parasitic diseases, with enteric infections being amongst the most frequently encountered. In its strategy to control such infection, Qatar has established the Pre-Employment Certificate (PEC) program which requires medical inspection before arrival in Qatar and which is mandatory for immigrant workers travelling to the country. To assess the reliability of the PEC, we conducted a survey of intestinal parasites, based on examination of stool samples provided by immigrant workers (n = 2,486) recently arrived in Qatar. Results: Overall prevalence of helminths was 7.0% and that of protozoa was 11.7%. Prevalence of combined helminths was highest among the western Asians and the highest prevalence of combined protozoan parasites was among workers from North to Saharan Africa. Analysis of temporal changes showed an increasing trend of protozoan infections over the investigated 3 years. A major contribution to this temporal change in prevalence came from Blastocystis hominis as well as from other protozoan species: Giardia duodenalis and Endolimax nana. Analysis of the temporal trend in species richness of the protozoan species showed a significant increase in the mean number of species harboured per subject across this period. Conclusion: The increase of protozoan infections over recent years raises some concerns. It suggests that screening protocols for applicants for visas/work permits needs to be revised giving more careful attention to the intestinal protozoan infections that potential immigrants may harbor.

Research paper thumbnail of Index of Contents (Volume 72)

Research paper thumbnail of 99 Performance of MALDI-TOF mass spectrometry method for identification of bacteria commonly isolated from cystic fibrosis patients

Research paper thumbnail of Comparison of intestinal parasitic infection in newly arrived and resident workers in Qatar

BackgroundThe rapid growth of Qatar in the last two decades has been associated with an enormous ... more BackgroundThe rapid growth of Qatar in the last two decades has been associated with an enormous expansion of building programs in its cities and in the provision of new service industries. This in turn has attracted a large influx of immigrant workers seeking employment in jobs associated with food handling, domestic service and the building industry. Many of these immigrants come from countries in the tropics and subtropics where intestinal parasitic infections are common.MethodsWe analyzed intestinal parasitic infections recorded in 2008 among immigrant and long-term resident workers in Doha city, Qatar (n = 1538). Stool examinations were carried out at the Hamad Medical Corporation and at the Medical Commission in Doha using standard procedures.ResultsOverall, 21.5% of subjects were infected with at least one of the species recorded (8 helminth and 4 protozoan species; the highest prevalence was for hookworms = 8.3%) and there were strong regional effects on prevalence of helmin...

Research paper thumbnail of Serum Uric Acid Level Is Positively Associated With Higher Bone Mineral Density at Multiple Skeletal Sites Among Healthy Qataris

Frontiers in Endocrinology

BackgroundOxidative stress has been implicated as a fundamental mechanism in the decline of bone ... more BackgroundOxidative stress has been implicated as a fundamental mechanism in the decline of bone mass. Although serum uric acid (SUA) has potent antioxidant properties, the findings of many epidemiological and experimental studies couldn’t draw a clear conclusion on the relation between SUA and bone health. We aim to investigate the association between SUA and bone mineral density (BMD) at different skeletal sites among healthy Qataris.MethodologyA cross-sectional analysis including total-body and site-specific bone mineral density scores and other serological markers of 2981 healthy Qatari adults (36.4 ± 11.1 years) from the Qatar biobank database was conducted. The study participants were divided into quartiles based on the level of SUA, and the BMD was measured using dual-energy X-ray absorptiometry (DXA). Multiple regression analyses were applied to investigate the association between SUA and BMD adjusting for multiple confounding factors.ResultsHigh levels of SUA were significa...

Research paper thumbnail of Genetic Diversity and Prevalence of Giardia duodenalis in Qatar

Frontiers in Cellular and Infection Microbiology

BackgroundGiardia duodenalis is a common human intestinal parasite worldwide, and the causative a... more BackgroundGiardia duodenalis is a common human intestinal parasite worldwide, and the causative agent of diarrhea, with the severity of disease ranging from asymptomatic to intense and debilitating infection. G. duodenalis is known to consist of eight genetically distinct assemblages, named from A to H. No data available on the genotypes and genetic diversity of G. duodenalis circulating in Qatar.MethodsWe genotyped 54 human Giardia isolates, collected from asymptomatic immigrants in Qatar, using a multilocus genotyping (MLGs) tool. We also investigated relationships between the subjects’ genotypes and their demographic data.ResultsGenomic DNA from 54 isolates were tested by PCR and sequence analysis at three loci: glutamate dehydrogenase (gdh), β-giardin (bg) and triose phosphate (tpi)). Assemblage A was identified in nine (16.67%), assemblage B in thirty (55.55%), and a mixture of assemblages A+B in fifteen (27.78%) isolates. All assemblage A isolates, genotyped in different loci,...

Research paper thumbnail of COVID-19 Vaccine Hesitancy in a Representative Education Sector Population in Qatar

Vaccines

Even though vaccination programs have now started in earnest across the globe and in Qatar, vacci... more Even though vaccination programs have now started in earnest across the globe and in Qatar, vaccine hesitancy remains a barrier to effectively tackling the pandemic. Many factors influence willingness to take vaccines including safety, efficacy, and side effects. Given their proximity to research and education, university students and employees represent an interesting cohort in which to investigate vaccine hesitancy. The aim of this study was to assess the attitudes of Qatar University employees and students towards the COVID-19 vaccine. In total, 231 employees and 231 students participated in an online cross-sectional study in February 2021. Of the sample, 62.6% were willing to take a vaccine against COVID-19. Participants with or taking postgraduate degrees were more willing to take the vaccine compared to participants with or taking a diploma or bachelor’s degree (p < 0.001). Males had a higher rate of vaccine acceptance (p < 0.001). In the group that regarded flu vaccinat...

Research paper thumbnail of A Whole-Genome Sequencing Association Study of Low Bone Mineral Density Identifies New Susceptibility Loci in the Phase I Qatar Biobank Cohort

Journal of Personalized Medicine

Bone density disorders are characterized by a reduction in bone mass density and strength, which ... more Bone density disorders are characterized by a reduction in bone mass density and strength, which lead to an increase in the susceptibility to sudden and unexpected fractures. Despite the serious consequences of low bone mineral density (BMD) and its significant impact on human health, most affected individuals may not know that they have the disease because it is asymptomatic. Therefore, understanding the genetic basis of low BMD and osteoporosis is essential to fully elucidate its pathobiology and devise preventative or therapeutic approaches. Here we sequenced the whole genomes of 3000 individuals from the Qatar Biobank and conducted genome-wide association analyses to identify genetic risk factors associated with low BMD in the Qatari population. Fifteen variants were significantly associated with total body BMD (p < 5 × 10−8). Of these, five variants had previously been reported by and were directionally consistent with previous genome-wide association study data. Ten variant...

Research paper thumbnail of The Role of Soluble Uric Acid in Modulating Autophagy Flux and Inflammasome Activation during Bacterial Infection in Macrophages

Biomedicines

Autophagy is a homeostatic process that regulates and recycles intracellular structures and is a ... more Autophagy is a homeostatic process that regulates and recycles intracellular structures and is a host defense mechanism that facilitates bacterial clearance. Uric acid in plasma is a major antioxidant but in certain conditions acts as an inflammatory danger signal. The aim of this study is to investigate the effect of soluble uric acid on autophagy and the inflammatory responses in macrophages during bacterial infection. Herein, we employed murine RAW264.7 macrophages that express uricase enzyme and human THP-1 cells that are uricase-deficient. Three different strains of Staphylococcus aureus and two different strains of Klebsiella pneumoniae were used to infect macrophages in presence and absence of soluble uric acid. We found that soluble uric acid enhanced autophagy flux in infected macrophages. We observed that IL-1β increased during bacterial infection but decreased when macrophages were co-stimulated with bacteria and uric acid. In contrast to IL-1β, soluble uric acid did not ...

Research paper thumbnail of Cryptosporidium spp., prevalence, molecular characterisation and socio-demographic risk factors among immigrants in Qatar

PLOS Neglected Tropical Diseases

Background The World Health Organization WHO has estimated that in developed countries, up to 30%... more Background The World Health Organization WHO has estimated that in developed countries, up to 30% of the population may suffer from foodborne diseases each year, and that in developing countries up to 2 million deaths per annum can be attributed to cryptosporidiosis. Reports have already emphasized the role of immigrants in outbreaks of parasitic diseases especially those working in food processing industries. Methodology/Principal findings Herein we assessed Cryptosporidium spp. infections among immigrants in Qatar with a special focus on food handlers and housemaids. The overall prevalence of Cryptosporidium spp. by q-PCR among 839 asymptomatic subjects was 4.5%. Based on the Gp60 gene, the majority of isolates were identified as C. parvum subtype IIdA20G1b. The positive sample for C. hominis was subtyped as IeA12G3T3. Seven mixed infections were also identified (four C. parvum + C. hominis, and three C. parvum + C. meleagridis). The prevalence of Cryptosporidium spp. did not differ significantly between the sexes or age classes but varied significantly between subjects affiliated to different religions with the lowest prevalence among the Muslims. Multifactorial analysis retained also marked significance with education, income, and a house contents index. Conclusions/Significance Our results contribute to a better understanding of the epidemiology of cryptosporidiosis and the risk factors associated with the likelihood of carrying this infection among immigrant workers from developing countries.

Research paper thumbnail of Seroprevalence of Toxoplasma Gondii Among Stray Cats in Qatar

Qatar Foundation Annual Research Conference Proceedings Volume 2016 Issue 1

Research paper thumbnail of Molecular Analysis of the Enteric Protozoa Associated with Acute Diarrhea in Hospitalized Children

Frontiers in Cellular and Infection Microbiology

Pediatric diarrhea is a common cause of death among children under 5 years of age. In the current... more Pediatric diarrhea is a common cause of death among children under 5 years of age. In the current study, we investigated the frequency of intestinal parasites among 580 pediatric patients with chronic diarrhea. Parasitic protozoa (all species combined) were detected by molecular tools in 22.9% of the children and the most common parasite was Cryptosporidium spp. (15.1%). Blastocystis hominis was detected in 4.7%, Dientamoeba fragilis in 4%, Giardia duodenalis in 1.7%, and Entamoeba histolytica in 0.17%. Protozoan infections were observed among all regional groups, but prevalence was highest among Qatari subjects and during the winter season. Typing of Cryptosporidium spp. revealed a predominance of Cryptosporidium parvum in 92% of cases with mostly the IIdA20G1 subtype. Subtypes IIdA19G2, IIdA18G2, IIdA18G1, IIdA17G1, IIdA16G1, and IIdA14G1 were also detected. For Cryptosporidium hominis, IbA10G2 and IbA9G3 subtypes were identified. This study provides supplementary information for implementing prevention and control strategies to reduce the burden of these pediatric protozoan infections. Further analyses are required to better understand the local epidemiology and transmission of Cryptosporidium spp. in Qatar.