Caractérisation génétique et phénotypique de cryptosporidium : de la souris à l’homme

Parasites of the genus Cryptosporidium comprise species infecting the gastrointestinal or respiratory tract of a wide variety of vertebrates including humans. These intracellular protists are the agents of a cosmopolitan zoonosis, with féco-oral transmission, cryptosporidiosis. Recent work from our laboratory, showed that the zoonotic species Cryptosporidium parvum is capable to induce digestive neoplasia in a SCID Severe Combined Immunodeficiency Mice (SCID) model, treated or not with dexamethasone. However C. muris, another species of Cryptosporidium, induces chronic infection in this rodent model but is not associated with neoplastic transformation.For all these reasons, it seemed interesting to carry out a thesis project articulated around three different axes: epidemiology, transmission and pathogenesis of the Cryptosporidium infection. We focused initially on the molecular epidemiology and genetic biodiversity of this parasite among human populations in North Lebanon. We found a Cryptosporidium prevalence of 5% among the general population, being C. hominis the predominant species. This prevalence could reach until 10% in symptomatic patients and children. This is the first epidemiological data about cryptosporidiosis in this country.Secondly, we studied the transmission routes and the main risk factors associated with the transmission of this parasite. To do this, a first study was conducted in parallel among animal populations in North Lebanon and France. The reported data suggest a predominance of an anthroponotic route of transmission for cryptosporidiosis in Lebanon, but the results of genotyping does not exclude the presence of zoonotic transmission. Other studies conducted in France, especially based on collection of stool samples in the zoos of Palmyre (Royan) and Lille showed that Cryptosporidium spp were present in less than 1% of captivity animals. The low prevalence strongly demonstrates that these animals play a negligible role as potential reservoirs of infection. While in wild fish, we could identify the presence of C. parvum, a zoonotic species, in the stomach and the gut of fish. These data suggest that the fish could be a natural host of C. parvum and a potential source of contamination for humans, animals but also for the environment.Finally, the third topic aimed to study the pathogenicity of this parasite. Firstly, we explored metabolic pathways potentially involved in the development of C. parvum-induced ileo-caecal oncogenesis in the SCID model treated with dexamethasone (SCID-D). We searched for alterations in genes or proteins commonly involved in cell cycle, differentiation or cell migration, such as β-catenin, Apc, E-cadherin, Kras and p53. We were able to show that the Wnt pathway was involved in this process. Finally, we wanted to study the association between digestive cancer and parasitism with Cryptosporidium in humans. Cryptosporidium molecular detection was therefore carried out in colonic and gastric biopsies belonging to patients with and without digestive cancers of recent diagnosis collected in North Lebanon. A statistically significant difference was observed between the prevalence of cryptosporidiosis found among the population of patients with digestive cancer (17%) and that of the control group consisting of non-cancer patients but with digestive symptoms (7%) (p-value = 0.03). All these data obtained in animals and humans strengthens the importance of this parasite in public health.Les parasites du genre Cryptosporidium comprennent des espèces infectant le tractus gastro-intestinal ou respiratoire d’un grand nombre de vertébrés y compris l'homme. Ces protistes intracellulaires sont les agents d’une zoonose cosmopolite à transmission oro-fécale, la cryptosporidiose. Au vu des travaux de notre laboratoire, nous savons à présent que Cryptosporidium parvum est également capable d’induire des néoplasies digestives chez un modèle murin SCID (Severe Combined Immunodeficiency mice), traitées ou pas par la dexaméthasone. Alors que C. muris, une autre espèce de Cryptosporidium, induit une infection chronique non associée à des transformations néoplasiques.Pour toutes ces raisons, il nous est apparu intéressant d’effectuer un travail de thèse articulé autour de trois axes principaux, l’épidémiologie, la transmission et la pathogénicité du parasite Cryptosporidium. Nous nous sommes intéressés dans un premier temps à l’épidémiologie moléculaire et la biodiversité génétique de Cryptosporidium dans des populations humaines de la région du Nord-Liban. Ceci nous a permis de mettre en évidence une prévalence de 5% de Cryptosporidium chez la population générale avec une prédominance de C. hominis. Ce qui constituait les premières données épidémiologiques de la cryptosporidiose au Liban. Ensuite d’autres études nous ont permis de montrer que cette prévalence pouvait atteindre même 10% chez les patients symptomatiques et les enfants.Dans un second temps, nous avons voulu étudier le mode de transmission du parasite et les facteurs de risque pouvant y être associés. Pour ce faire, une recherche du parasite a été réalisée aussi bien au Liban qu’en France chez des animaux d’élevage, sauvages, de compagnie et en captivité. Une première étude a été réalisée chez des patients et des bovins du Nord-Liban. L’ensemble des données rapportées nous permettent de suggérer un mode de transmission de la cryptosporidiose majoritairement anthroponotique au Liban, mais les résultats du génotypage ne permettent pas d’exclure la présence d’une transmission zoonotique. D’autres études réalisées en France, notamment sur des échantillons de selles collectées auprès des zoos de la Palmyre (à Royan) et de Lille ont montré un taux de prévalence de Cryptosporidium spp inférieur à 1%. Ces animaux ne semblent donc pas être un réservoir potentiel de cette infection. Alors que chez les poissons sauvages, nous avons pu identifier la présence entre autre de l’espèce zoonotique C. parvum dans l’estomac et l’intestin des poissons. Ceci nous permet de considérer les poissons comme étant une source de contamination potentiel pour l’homme, l’animal mais également pour l’environnement.Enfin le troisième axe avait pour but d’étudier la pathogénicité de ce parasite. Pour commencer nous avons voulu explorer les mécanismes de la cancérogénèse induite par la souche IOWA de C. parvum au niveau de la région iléocæcale des souris SCID traitées par la dexaméthasone (SCID-D). Pour ce faire nous nous sommes intéressés à quatre marqueurs de voies de signalisation cellulaires impliquées dans la survenue de cancers colorectaux (APC, Bêta-caténine, P53 et K‐ras). Nous avons ainsi pu montrer que la voie Wnt était impliquée dans ce processus. Ensuite nous avons voulu étudier l’association entre la pathologie cancéreuse et le parasitisme par Cryptosporidium chez l’homme. Une recherche du parasite a donc été réalisée dans des biopsies d’origines coliques et gastriques inclues en paraffine appartenant à des patients atteints ou non de cancers digestifs. Une différence significative a été rapportée entre la prévalence de la cryptosporidiose retrouvée chez la population de patients présentant des lésions cancéreuses (17%) et celle du groupe control constitué de patients non cancéreux mais présentant des symptômes (7%) p-value = 0.03. L’ensemble de ces données obtenues chez l’animal et chez l’homme montre que ce parasite a un impact important en santé humaine et animale

Antimicrobial resistance among canine enterococci in the northeastern United States, 2007–2020

IntroductionAntimicrobial resistance (AMR) is a growing and complex One Health concern worldwide, threatening the practice of human and veterinary medicine. Although dogs are a potential reservoir of multidrug-resistant bacteria, there are very few surveillance studies on AMR from the canine population in the United States. Here, we assessed the antimicrobial susceptibility patterns, identified temporal resistance and minimum inhibitory concentration trends, and described associations between resistance phenotypes among canine clinical enterococci in the northeastern United States.MethodsThrough a large-scale retrospective study design, we collected species identification, minimum inhibitory concentration, and clinical data from 3,659 canine enterococci isolated at the Cornell University Animal Health Diagnostic Center between 2007 and 2020. We used the Mann-Kendall test, Sen’s slope, multivariable logistic regression, and survival analysis models to detect the presence of a significant trend in resistance over the study period.ResultsEnterococcus faecalis was the most prevalent species (67.1% of isolates), followed by Enterococcus faecium (20.4%). We found high levels of AMR among enterococci to almost all the tested antimicrobials, particularly E. faecium. The lowest percentage of resistance was to vancomycin and chloramphenicol. Multidrug resistance was common (80% of E. faecium and 33% of E. faecalis) and 31 isolates were extensively drug resistant. Multidrug resistance among E. faecium increased over time, but not in E. faecalis. Resistance to penicillins, enrofloxacin, and rifampin increased during the study period, but resistance to tetracyclines is on a downward trajectory compared to AMR data from the last decade. Emerging vancomycin-resistant E. faecalis (0.3%) and E. faecium (0.8%) infections in the canine population are of great concern to both human and animal health. One E. faecium isolate with acquired vancomycin resistance was identified in 2017 and four vancomycin-resistant enterococci isolates were identified in 2020.ConclusionThere is a crucial need to make rational prescribing decisions on the prudent use of antimicrobials and improve the quality of care for patients, especially when empirical antimicrobial treatment for enterococcal infection is common

Antibiotic Susceptibility of Salmonella spp., Shigella spp. and enteropathogenic Escherichia coli strains isolated from diarrheic children in Tripoli, North Lebanon

Background. – Enteric infections are a leading cause of diarrheal disease and death in infants and young children, particularly in the developing regions. The aim of this study is to determine the antibiotic susceptibility of three Enterobacteriaceae enteropathogens (Salmonella spp., Shigella spp. and enteropathogenic Escherichia coli (EPEC)) isolated from hospitalized diarrheic children in North Lebanon during the period of 7 years.Methods and Findings. – 172 Enterobacteriaceae enteropathogens strains were isolated from fecal or blood specimens of 158 hospitalized diarrheic children collected at Nini hospital in Tripoli, North Lebanon. Culture, identification and antibiotic susceptibility of strains were carried out through conventional tools according to standard protocols proposed by the REMIC group and the recommendations of the European Committee on Antimicrobial Susceptibility Testing. Out of 172, 158 (91.9%) Enterobacteriaceae enteropathogens strains were isolated from stool samples and only 14 (8.1%) were isolated from blood cultures. EPEC were predominant (78/172; 45.3%), followed by Salmonella spp. (64/172; 37.2%) and Shigella spp. (30/172; 17.5%). According to API identification and immunological serotyping reports of Salmonella isolates, Salmonella Typhi was the predominant serotype (32/64; 50%). During the study period, antibiotics susceptibility testing showed that around 50% and 25% of the isolates were resistant to ampicillin and extended-spectrum cephalosporins, respectively. Overall, Salmonella Typhi strains were the most susceptible to antibiotics.Conclusion. – Our study revealed a relatively high antibiotic resistance rate of EPEC, Shigella spp. and non-Typhi Salmonella strains among studied population. The findings of this study provide useful information to survey, prevent and control diarrheal disease and antimicrobial resistance in Lebanon

First data on antimicrobial susceptibility patterns of Moraxella catarrhalis isolates in Lebanon

Background. Moraxella catarrhalis is an important bacterial pathogen. Although national data have shown an increase in the levels of antimicrobial resistance in clinical settings in Lebanon, there is a lack of data regarding this human pathogen. This study aimed to determine for the first time the antimicrobial susceptibility profiles of M. catarrhalis isolates in Lebanon. Methods. A total of 34 M. catarrhalis strains were isolated from clinical specimens during the period from November 2010 to March 2019. Bacterial identification was carried out using matrix assisted laser desorption ionization–time of flight mass spectrometry. Antibiotic susceptibility of all isolates was performed according the recommendations of the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Results. A total of 34 non-duplicated M. catarrhalis strains were isolated from nose (n=19), ear (n=7), sputum (n=5), blood (n=1), eye (n=1), and throat (n=1) of patients referred to Nini Hospital in Tripoli, North governorate of Lebanon. Regarding antibiotic susceptibility rates, the percent susceptibility is 100% to the majority of antibiotics, except ampicillin (7.4%), trimethoprim-sulfamethoxazole (85.3%), nalidixic acid (85.3%), and ciprofloxacin (97.1%). Conclusion. To our knowledge, this study is the first investigation regarding the antimicrobial susceptibility patterns of M. catarrhalis isolates in Lebanon. In addition to the high level of resistance to ampicillin, our findings showed the emergence of resistance to trimethoprim-sulfamethoxazole, nalidixic acid and ciprofloxacin. Even if this study provides useful information to develop effective empirical treatment, we recommend the implementation of reliable diagnostic tools to guide appropriate treatment

Prevalence and antibiotic susceptibility of ear pathogens isolated from patients in Tripoli, north of Lebanon

Background. Urinary tract infection (UTI) is a severe public health problem. However, infected patients are usually treated empirically without preceding culture or antibiotics susceptibility testing, which may increase the antibiotic resistance level. The aim of this study is to determine the prevalence and antibiotic susceptibility patterns of common bacterial uropathogens isolated in Akkar governorate, North Lebanon. Methods. Spot midstream from urine samples from 9662 patients presenting UTI symptoms who came to Youssef Hospital Center located in Akkar governorate, were collected in sterile plastic cups. Culture, identification and antibiotic susceptibility testing were performed through conventional tools according to the manufacturer’s recommended procedures and the recommendations of the European Committee on Antimicrobial Susceptibility Testing. Results. Overall, a total of 1009 bacterial uropathogens were isolated. Escherichia coli was predominant and represented 72.5% of all isolates , followed by Klebsiella pneumoniae (8.2%), Enterococcus spp. (5.5%), Pseudomonas aeruginosa (4.5%), Proteus spp. (3%), Enterobacter spp. (2%), Staphylococcus aureus (2%), Streptococcus agalactiae (1.6%), Staphylococcus saprophyticus (0.4%), Acinetobacter baumannii (0.2%) and Providencia rettgeri (0.1%). Moreover, the mean antibiotic resistance rates of isolates was relatively high, but similar to previous investigations reported in our country. Conclusion. To our knowledge, this is the first investigation reporting epidemiological data regarding the prevalence and antibiotic susceptibility patterns of uropathogens isolated from patients in Akkar governorate. Our data indicated the urgent need of a strategic plan to tackle antibiotic resistance, particularly in deprived regions with poor healthcare structures such as Akkar governorate. DOI: http://dx.doi.org/10.3823/80

Changes in blood and urine parameters among pregnant women during third trimester

Background: During pregnancy, the pregnant lady undergoes significant anatomical and physiological changes in order to nurture and accommodate the developing fetus. These changes begin after conception and affect every organ system in the body.Methods: The study was carried out in the United Arab Emirates - Ajman (Thumbay Hospital) during the period of (March - Jun) in the year of 2018 to estimate HbA1c% levels, hematological blood parameters and urine culture in healthy pregnant women during 3rd trimester. The study was conducted on (108) healthy pregnant women during3rd trimester. Urine culture was performed to detect the growth of bacteria after the culture, gram stain was done to differentiate the bacteria followed by biochemical test to detect the type of bacteria.Results: A total 26 (79%) of patients had normal HbA1c% result while 7(21%) had elevated HbA1c% result. The results of HbA1c% in last trimester mean±SD (range) HbA1c% (n=33) were 5.5±0.52% (111.5±14.8 mg/dL). Also, our results showed strong positive correlation between HbA1% with estimated Average blood glucose (r=0.78, P value=0.00), and weak positive correlation between HbA1 with age (years) (r=0.2, P value=0.02). Bacterial culture showed that two positive results of stenotrophomonas maltophilia was isolated, three cases of Staphylococcus aureus was isolated and three cases of staphylococcus saprophyticus. Hematological profile showed a clinically significant (≤ 0.05) in Hb mean 11.47, P value 0.001, HCT mean, 33.9 P value 0.001 and MCV mean 73.7 value 0.001. No clinically significant (≥ 0.05) in RBCs mean 3.93, P value 0.010, MCH mean 27.3 P value 0.061 and MCHC mean 30.9 P value 0.134.Conclusions: Our study conclude that estimation of HbA1c%, hematological blood parameters and urine culture level in last trimester will be helpful in diagnosis, monitoring and predicting fetal distress

Real-time pen input system for writing utilizing stereo vision

A system that captures handwritten words on a piece of paper utilizing two cameras which observe and track a pen’s tip lateral movement is presented. The system tracks the pen’s tip in real-time based on the two images vision using colored markers. The stereo camera is calibrated for accurate threedimensional (3D) positioning of the pen’s tip. Pen’s tip 3D coordinates are then being used to re-construct the handwritten input into computer image. Experimental results show that the system can detect and track handwriting within 1mm accuracy on the y-axis and 7 mm accuracy on the x-axis (depth)

Prevalence and antibiotic susceptibility patterns of bacteria causing urinary tract infections in Youssef Hospital Center: first report from Akkar governorate, North of Lebanon

Background. Urinary tract infection (UTI) is common infection feature worldwide.   Infected patients are usually treated empirically treated without culture or antibiotics susceptibility testing, and which may lead to increase antibiotic resistance level. This study aims to determine the prevalence and antibiotic susceptibility patterns of common uropathogenic bacteria isolated at Youssef Hospital Center, Akkar governorate, North of Lebanon. Methods. Spot midstream of urine samples from 9662 patients with UTI symptoms who came for medical investigation to Youssef Hospital Center located in Akkar governorate.  Urine specimens were collected in sterile plastic bottles. Culture, identification and antibiotic susceptibility testing were performed using conventional tools according to the recommendations of the European Committee on Antimicrobial Susceptibility Testing. Results.  A total of 1009 bacterial uropathogens were isolated. Escherichia coli was most presented (72.5%) of all isolates, followed by Klebsiella pneumoniae (8.2%), Enterococcus spp. (5.5%), Pseudomonas aeruginosa (4.5%), Proteus spp. (3%), Enterobacter spp. (2%), Staphylococcus aureus (2%), Streptococcus agalactiae (1.6%), Staphylococcus saprophyticus (0.4%), Acinetobacter baumannii(0.2%) and Providencia rettgeri (0.1%). Moreover, the mean antibiotic resistance rates of isolates was relatively high, but comparable to previously published data in Lebanon. Conclusion. To the best of our knowledge, this is the first investigation reporting epidemiological data regarding the prevalence and antibiotic susceptibility patterns of bacterial uropathogens isolated from patients in the Akkar governorate. Our data indicated the urgent need of a strategic plan to tackle antibiotic resistance, particularly in deprived regions with poor healthcare centers.   Keywords: Uropathogens, Epidemiology, Antibiotic susceptibility, Risk factors, Akkargovernorate, North Lebanon

Molecular Characterization of Antimicrobial Resistance and Virulence Genes of Bacterial Pathogens from Bovine and Caprine Mastitis in Northern Lebanon

Mastitis is an infectious disease encountered in dairy animals worldwide that is currently a growing concern in Lebanon. This study aimed at investigating the etiology of the main mastitiscausing pathogens in Northern Lebanon, determining their antimicrobial susceptibility profiles, and identifying their antimicrobial resistance (AMR) genes. A total of 101 quarter milk samples were collected from 77 cows and 11 goats presenting symptoms of mastitis on 45 dairy farms. Bacterial identification was carried out through matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Antimicrobial susceptibility was tested by disc diffusion and broth microdilution methods. Molecular characterization included polymerase chain reaction (PCR) screening for genes encoding extended-spectrum beta-lactamases (ESBLs) and plasmid-mediated AmpC among Enterobacterales isolates, and virulence factors among Staphylococcus isolates. Escherichia coli isolates were subjected to phylogenetic typing by a quadruplex PCR method. The most frequently identified species were Streptococcus uberis (19.2%), Streptococcus agalactiae (15.1%), E. coli (12.3%), and Staphylococcus aureus (10.96%). Gram-positive bacteria were resistant to macrolides and etracycline, whereas gram-negative bacteria displayed resistance to ampicillin and tetracycline. Two ESBL genes, blaTEM (83.3%) and blaOXA (16.7%), and one AmpC beta-lactamase gene, blaCMY-II (16.7%), were detected among six E. coli isolates, which mainly belonged to phylogenetic group B1. Among Staphylococcus spp., the mecA gene was present in three isolates. Furthermore, four isolates contained at least one toxin gene, and all S. aureus isolates carried the ica operon. These findings revealed the alarming risk of AMR in the Lebanese dairy chain and the importance of monitoring antimicrobial usage

Characterization of resistance genes to macrolides, lincosamides and streptogramins (MLS) among clinical isolates of Staphylococcus aureus in North Lebanon

Background. – Staphylococcus aureus is one of the most significant pathogens causing significant morbidity and mortality. Moreover, the incidence of MLS-resistant Staphylococcus aureus infections continues to grow globally.Objective. – The aim of this study is to examine the expression of resistance of Staphylococcus aureus (S. aureus) isolates to MLS and the prevalence of genes involved in this resistance by PCR.Methods. – 38 strains of S. aureus MLS-resistant (resistant at least for one macrolide) were isolated in the sector of microbiology at Nini Hospital in North Lebanon. The disk diffusion method was used to determine the phenotype of the MLS resistance. The resistance genes involved were detected by PCR using specific gene primers for ermA, ermB, ermC, msrA, linA, mefA, vat and vgb genes.Results. – A total of 55.3% of the isolates were positive for inducible phenotype (iMLSB), 15.8% for the constitutive phenotype (cMLSB), 23.7% for MSB phenotype and 5.2% for L phenotype. The ermC gene was the most prevalent (52.6%), while ermA, ermB, msrA and linA genes were observed with lower prevalence. However, a combination of several of these genes was detected. The vgb, vat and mefA genes were not detected in any of the clinical isolates.Conclusion. – To our knowledge, this study is the first investigation regarding characterization of MLS resistance genes in clinical isolates of S. aureus in Lebanon. The study revealed a high prevalence of the inducible resistance to lincosamides (iMLSB phenotype) and the most prevalent resistance determinants was ermC