An assessment of potential biomarkers of environment enteropathy and its association with age and microbial infections among children in Bangladesh.

Interventional studies targeting environment enteropathy (EE) are impeded by the lack of appropriate, validated, non-invasive biomarkers of EE. Thus, we aimed to validate the association of potential biomarkers for EE with enteric infections and nutritional status in a longitudinal birth cohort study. We measured endotoxin core antibody (EndoCab) and soluble CD14 (sCD14) in serum, and myeloperoxidase (MPO) in feces using commercially available enzyme-linked immunosorbent assay (ELISA) kits. We found that levels of serum EndoCab and sCD14 increase with the cumulative incidence of enteric infections. We observed a significant correlation between the fecal MPO level in the children at 24 months of age with the total number of bacterial and viral infections, the total number of parasitic infections, and the total number of diarrheal episodes and diarrheal duration. We observed that the levels of serum EndoCab, sCD14, and fecal MPO at 3 months of age were significantly associated with whether children were malnourished at 18 months of age or not. Biomarkers such as fecal MPO, serum EndoCab and sCD14 in children at an early age may be useful as a measure of cumulative burden of preceding enteric infections, which are predictive of subsequent malnutrition status and may be useful non-invasive biomarkers for EE.

The role of MUC2 mucin in intestinal homeostasis and the impact of dietary components on MUC2 expression.

MUC2 mucin is an important secretory protein found in the human gut. Recent studies indicated that MUC2 mucin plays a role in the protection of gut barrier, the regulation of microbiome homeostasis and the prevention of diseases. In this review, the physiological properties of MUC2 mucin and its interactions with the intestinal microbiome are firstly discussed. Its roles in intestinal diseases including inflammatory bowel disease, colorectal cancer and parasitic infections are concluded. We also reviewed dietary components known to have modulative effects on MUC2 mucin expression, such as polysaccharides, amino acids and polyphenols.

Epidemiology of paediatric gastrointestinal colonisation by extended spectrum cephalosporin-resistant Escherichia coli and Klebsiella pneumoniae isolates in north-west Cambodia.

BACKGROUND: Extended-spectrum cephalosporin resistance (ESC-R) in Escherichia coli and Klebsiella pneumoniae is a healthcare threat; high gastrointestinal carriage rates are reported from South-east Asia. Colonisation prevalence data in Cambodia are lacking. The aim of this study was to determine gastrointestinal colonisation prevalence of ESC-resistant E. coli (ESC-R-EC) and K. pneumoniae (ESC-R-KP) in Cambodian children/adolescents and associated socio-demographic risk factors; and to characterise relevant resistance genes, their genetic contexts, and the genetic relatedness of ESC-R strains using whole genome sequencing (WGS). RESULTS: Faeces and questionnaire data were obtained from individuals < 16 years in north-western Cambodia, 2012. WGS of cultured ESC-R-EC/KP was performed (Illumina). Maximum likelihood phylogenies were used to characterise relatedness of isolates; ESC-R-associated resistance genes and their genetic contexts were identified from de novo assemblies using BLASTn and automated/manual annotation. 82/148 (55%) of children/adolescents were ESC-R-EC/KP colonised; 12/148 (8%) were co-colonised with both species. Independent risk factors for colonisation were hospitalisation (OR: 3.12, 95% CI [1.52-6.38]) and intestinal parasites (OR: 3.11 [1.29-7.51]); school attendance conferred decreased risk (OR: 0.44 [0.21-0.92]. ESC-R strains were diverse; the commonest ESC-R mechanisms were blaCTX-M 1 and 9 sub-family variants. Structures flanking these genes were highly variable, and for blaCTX-M-15, - 55 and - 27 frequently involved IS26. Chromosomal blaCTX-M integration was common in E. coli. CONCLUSIONS: Gastrointestinal ESC-R-EC/KP colonisation is widespread in Cambodian children/adolescents; hospital admission and intestinal parasites are independent risk factors. The genetic contexts of blaCTX-M are highly mosaic, consistent with rapid horizontal exchange. Chromosomal integration of blaCTX-M may result in stable propagation in these community-associated pathogens.

The role of myeloid-derived suppressor cells in chronic infectious diseases and the current methodology available for their study.

An effective pathogen has the ability to evade the immune response. The strategies used to achieve this may be based on the direct action of virulence factors or on the induction of host factors. Myeloid-derived suppressor cells (MDSCs) are immune cells with an incredible ability to suppress the inflammatory response, which makes them excellent targets to be exploited by pathogenic bacteria, viruses, or parasites. In this review, we describe the origin and suppressive mechanisms of MDSCs, as well as their role in chronic bacterial, viral, and parasitic infections, where their expansion seems to be essential in the chronicity of the disease. We also analyze the disadvantages of current MDSC depletion strategies and the different in vitro generation methods, which can be useful tools for the deeper study of these cells in the context of microbial infections.

Biofilm testing of microbiota: An essential step during corneal scrap examination in Egyptian acanthamoebic keratitis cases.

PURPOSE: To detect co-infections in the culture-proven acanthamoebic keratitis (AK) cases, and to test the capability of biofilm formation in the isolated microbiota. The clinical findings, habit of wearing contact lens and in-vitro antibiotic resistance were analyzed further according to the biofilm formation capability. METHODS: After clinical examination, corneal scraps and swabs were taken from 240 clinically suspected AK cases, for Acanthamoeba and microbiological cultures. In cases of keratoplasty, trimmed corneal tissue was collected and sent for histopathological examination. Scanning electron microscopy was done for some samples. Biofilm formation capability was investigated using a tissue culture plate method. Antibiotic resistance pattern was determined using a modified-Kirby-Bauer disc diffusion method. RESULTS: In 102 AK culture proven cases, 11 had no co-infection, 74 had a single co-infection and 17 had double co-infections. Enterobactericae and Aspergillus were the commonest bacterial and fungal isolates, respectively. Regarding the biofilm formation, 64.7% of Enterobactericae, 50% of Pseudomonas aeuroginosa, 43.75% of Staph aureus, 76.92% of Streptococcus pneumoniae, 28.57% of Corynebacterium, 60% of α-haemolytic streptococci, 40% of Acinetobacter, 100% of Candida and 77.8% Aspergillus isolates were biofilm producers. Severe manifestations were more frequently reported in cases co-infected with biofilm producers than with non-biofilm producers. Generally, high percentages of the biofilm forming bacterial isolates were sensitive to antibiotics in-vitro. CONCLUSIONS: Routine investigations for co-infection and biofilm formation in addition to Acanthamoeba culture are strongly recommended in suspected AK cases. Co-infection with biofilm producers may precipitate extrinsic in-vivo drug resistance despite of the in-vitro sensitivity. Designing a biofilm-dissolving topical drug is highly recommended to enhance the response to the standard therapeutic regimen especially in the resistant AK cases.

Disentangling the effects of selection and loss bias on gene dynamics.

We combine mathematical modeling of genome evolution with comparative analysis of prokaryotic genomes to estimate the relative contributions of selection and intrinsic loss bias to the evolution of different functional classes of genes and mobile genetic elements (MGE). An exact solution for the dynamics of gene family size was obtained under a linear duplication-transfer-loss model with selection. With the exception of genes involved in information processing, particularly translation, which are maintained by strong selection, the average selection coefficient for most nonparasitic genes is low albeit positive, compatible with observed positive correlation between genome size and effective population size. Free-living microbes evolve under stronger selection for gene retention than parasites. Different classes of MGE show a broad range of fitness effects, from the nearly neutral transposons to prophages, which are actively eliminated by selection. Genes involved in antiparasite defense, on average, incur a fitness cost to the host that is at least as high as the cost of plasmids. This cost is probably due to the adverse effects of autoimmunity and curtailment of horizontal gene transfer caused by the defense systems and selfish behavior of some of these systems, such as toxin-antitoxin and restriction modification modules. Transposons follow a biphasic dynamics, with bursts of gene proliferation followed by decay in the copy number that is quantitatively captured by the model. The horizontal gene transfer to loss ratio, but not duplication to loss ratio, correlates with genome size, potentially explaining increased abundance of neutral and costly elements in larger genomes.

Parasites, microbiota and metabolic disease.

Recent years have witnessed a dramatic increase in diseases that are ascribed to alter metabolism eventually resulting in conditions including obesity, type-2 diabetes (T2D), cardiovascular disease and metabolic syndrome (MetS). Of the many factors to which this rise has been attributed, including diet, physical activity and inflammation, several studies have correlated these disease states with alterations in gut microbiota. Simultaneously, studies have demonstrated the ability of parasites to alter microbial communities within their shared niche, leading to alterations in inflammatory processes. However, very few reports have addressed how these changes to the microbiome may be a mechanism by which parasites influence not only inflammation but also metabolic states. In this review, we attempt to draw parallels between the three capacious topics and examine the interrelationship between them.

Parasitic and infectious diseases of the biliary tract in migrants and international travelers.

INTRODUCTION: In recent years, global and regional crises have led to extraordinary worldwide migration, accompanied by an increase in long-distance travel from Western countries. Both are linked to a rising incidence of rare parasitic and infectious diseases in first world countries, including in the biliary tract. Areas covered: A selective literature research in PubMed was performed to review the most important parasitic and infectious biliary diseases, which are caused by a wide variety of pathogens and may be latent over long periods, with chronic courses leading to cholangitis, hepatic failure or development of cholangiocarcinoma. Parasites such as Ascaris, Fasciola and Clonorchis/Opisthorchis are particularly important and may trigger biliary diseases or predisposition for bacterial superinfections. Viral or protozoal cholangitis is mainly a problem of impaired immunity. Expert commentary: Currently, these entities are still rare in migrants and long-distance travelers. However, a significant increase in Western countries has to be expected. Incidences are most likely underestimated because of protracted clinical latency. Diagnosis depends on the relevant pathogens, the host's immune status and the extent or distribution of biliary obstruction. Modern tomographic methods, ERCP and specific microbiological/parasitological/virological tests are of crucial diagnostic importance. Antimicrobial/antiparasitic/antiviral therapy along with ERCP and interventional sonography/radiology provide effective treatment options.

[Update in Infectious Diseases 2016]. / Actualización en Patología Infecciosa 2016.

Antimicrobial resistance increases it health, social and economic impact. in all areas (state, regional and local), initiatives to try to contain the problem of resistance arise. In the update of this year 2016, we study microbiological, epidemiological and clinical aspects of multi-resistant bacteria, as well as resources for therapeutic approach, from ancient to modern drugs from therapeutic combinations to optimization Stewardship programs. In the case of fungal infection, we analyze clinical scenarios with different species in yeast or new clinical settings in filamentous fungi. Taking paediatric population, homologies and differences with adults in invasive fungal infection were compared. Finally in the field of parasitology, treatment of severe malaria imported or that resistant to antimalarial drugs were reviewed.

Grandeur Alliances: Symbiont Metabolic Integration and Obligate Arthropod Hematophagy.

Several arthropod taxa live exclusively on vertebrate blood. This food source lacks essential metabolites required for the maintenance of metabolic homeostasis, and as such, these arthropods have formed symbioses with nutrient-supplementing microbes that facilitate their host's 'hematophagous' feeding ecology. Herein we highlight metabolic contributions of bacterial symbionts that reside within tsetse flies, bed bugs, lice, reduviid bugs, and ticks, with specific emphasis on B vitamin and cofactor biosynthesis. Importantly, these arthropods can transmit pathogens of medical and veterinary relevance and/or cause infestations that induce psychological and dermatological distress. Microbial metabolites, and the biochemical pathways that generate them, can serve as specific targets of novel control mechanisms aimed at disrupting the metabolism of hematophagous arthropods, thus combatting pest invasion and vector-borne pathogen transmission.

Human Parasites in Medieval Europe: Lifestyle, Sanitation and Medical Treatment.

Parasites have been infecting humans throughout our evolution. However, not all people suffered with the same species or to the same intensity throughout this time. Our changing way of life has altered the suitability of humans to infection by each type of parasite. This analysis focuses upon the evidence for parasites from archaeological excavations at medieval sites across Europe. Comparison between the patterns of infection in the medieval period allows us to see how changes in sanitation, herding animals, growing and fertilizing crops, the fishing industry, food preparation and migration all affected human susceptibility to different parasites. We go on to explore how ectoparasites may have spread infectious bacterial diseases, and also consider what medieval medical practitioners thought of parasites and how they tried to treat them. While modern research has shown the use of a toilet decreases the risk of contracting certain intestinal parasites, the evidence for past societies presented here suggests that the invention of latrines had no observable beneficial effects upon intestinal health. This may be because toilets were not sufficiently ubiquitous until the last century, or that the use of fresh human faeces for manuring crops still ensured those parasite species were easily able to reinfect the population.

Biological warfare: Microorganisms as drivers of host-parasite interactions.

Understanding parasite strategies for evasion, manipulation or exploitation of hosts is crucial for many fields, from ecology to medical sciences. Generally, research has focused on either the host response to parasitic infection, or the parasite virulence mechanisms. More recently, integrated studies of host-parasite interactions have allowed significant advances in theoretical and applied biology. However, these studies still provide a simplistic view of these as mere two-player interactions. Host and parasite are associated with a myriad of microorganisms that could benefit from the improved fitness of their partner. Illustrations of such complex multi-player interactions have emerged recently from studies performed in various taxa. In this conceptual article, we propose how these associated microorganisms may participate in the phenotypic alterations induced by parasites and hence in host-parasite interactions, from an ecological and evolutionary perspective. Host- and parasite-associated microorganisms may participate in the host-parasite interaction by interacting directly or indirectly with the other partner. As a result, parasites may develop (i) the disruptive strategy in which the parasite alters the host microbiota to its advantage, and (ii) the biological weapon strategy where the parasite-associated microorganism contributes to or modulates the parasite's virulence. Some phenotypic alterations induced by parasite may also arise from conflicts of interests between the host or parasite and its associated microorganism. For each situation, we review the literature and propose new directions for future research. Specifically, investigating the role of host- and parasite-associated microorganisms in host-parasite interactions at the individual, local and regional level will lead to a holistic understanding of how the co-evolution of the different partners influences how the other ones respond, both ecologically and evolutionary. The conceptual framework we propose here is important and relevant to understand the proximate basis of parasite strategies, to predict their evolutionary dynamics and potentially to prevent therapeutic failures.

Aetiology, epidemiology and clinical characteristics of acute moderate-to-severe diarrhoea in children under 5 years of age hospitalized in a referral paediatric hospital in Rabat, Morocco.

The objective of the study was to describe the aetiology, epidemiology and clinical characteristics of the principal causes of acute infectious diarrhoea requiring hospitalization among children under 5 years of age in Rabat, Morocco. A prospective study was conducted from March 2011 to March 2012, designed to describe the main pathogens causing diarrhoea in hospitalized children >2 months and less than 5 years of age. Among the 122 children included in the study, enteroaggregative Escherichia coli (EAEC) and rotavirus were the main aetiological causes of diarrhoea detected. Twelve (9.8 %) children were referred to an intensive care unit, while two, presenting infection by EAEC, and EAEC plus Shigella sonnei, developed a haemolytic uraemic syndrome. Additionally, six (4.9 %) deaths occurred, with EAEC being isolated in four of these cases. Diarrhoeagenic E. coli and rotavirus play a significant role as the two main causes of severe diarrhoea, while other pathogens, such as norovirus and parasites, seem to have a minimal contribution. Surveillance and prevention programmes to facilitate early recognition and improved management of potentially life-threatening diarrhoea episodes are needed.

High detection rates of enteropathogens in asymptomatic children attending day care.

BACKGROUND: Gastroenteritis morbidity is high among children under the age of four, especially amongst those who attend day care. OBJECTIVE: To determine the prevalence of a range of enteropathogens in the intestinal flora of children attending day care and to relate their occurrence with characteristics of the sampled child and the sampling season. METHODS: We performed three years of enteropathogen surveillance in a network of 29 child day care centers in the Netherlands. The centers were instructed to take one fecal sample from ten randomly chosen children each month, regardless of gastrointestinal symptoms at time of sampling. All samples were analyzed for the molecular detection of 16 enteropathogenic bacteria, parasites and viruses by real-time multiplex PCR. RESULTS: Enteropathogens were detected in 78.0% of the 5197 fecal samples. Of the total, 95.4% of samples were obtained from children who had no gastroenteritis symptoms at time of sampling. Bacterial enteropathogens were detected most often (most prevalent EPEC, 19.9%), followed by parasitic enteropathogens (most prevalent: D. fragilis, 22.1%) and viral enteropathogens (most prevalent: norovirus, 9.5%). 4.6% of samples related to children that experienced symptoms of gastroenteritis at time of sampling. Only rotavirus and norovirus were significantly associated with gastroenteritis among day care attendees. CONCLUSIONS: Our study indicates that asymptomatic infections with enteropathogens in day care attendees are not a rare event and that gastroenteritis caused by infections with these enteropathogens is only one expression of their presence.

Generalism and the evolution of parasite virulence.

The evolution of parasite-imposed host harm (virulence) will be affected by numerous factors, not least the range of hosts that parasites can infect. Here, we consider four ways that parasite host range (generalism) might directly affect observed levels of parasite virulence: costs of generalism, multiplicity of infection, maladaptive virulence, and host availability. Integrating parasite infectivity range with life-history evolution will generate novel general hypotheses for the evolutionary ecology of virulence, as well as explicit predictions about the virulence of emerging diseases resulting from host shifts.

Parasitic infection may be associated with discordant responses to QuantiFERON and tuberculin skin test in apparently healthy children and adolescents in a tuberculosis endemic setting, Ethiopia.

BACKGROUND: M. tuberculosis remains one of the world's deadliest pathogens in part because of its ability to establish persistent, latent infections, which can later reactivate to cause disease. In regions of the globe where disease is endemic, as much as 50% of the population is thought to be latently infected, complicating diagnosis and tuberculosis control. The tools most commonly used for diagnosis of latent M. tuberculosis infection are the tuberculin skin test and the newer interferon-gamma release assays, both of which rely on an antigen-specific memory response as an indicator of infection. It is clear that the two tests, do not always give concordant results, but the factors leading to this are only partially understood. METHODS: In this study we examined 245 healthy school children aged from 12 to 20 years from Addis Ababa, a tuberculosis-endemic region, characterised them with regard to response in the tuberculin skin test and QuantIFERON™ test and assessed factors that might contribute to discordant responses. RESULTS: Although concordance between the tests was generally fair (90% concordance), there was a subset of children who had a positive QuantIFERON™ result but a negative tuberculin skin test. After analysis of multiple parameters the data suggest that discordance was most strongly associated with the presence of parasites in the stool. CONCLUSIONS: Parasitic gut infections are frequent in most regions where M. tuberculosis is endemic. This study, while preliminary, suggests that the tuberculin skin test should be interpreted with caution where this may be the case.

Investigation of zoonotic infections among Auckland Zoo staff: 1991-2010.

Investigation was undertaken to assess the occurrence of zoonotic infection among staff at Auckland Zoological Park, New Zealand, in 1991, 2002 and 2010. Serial cross-sectional health surveys in 1991, 2002 and 2010 comprising a health questionnaire, and serological, immunological and microbiological analysis for a range of potential zoonotic infections were performed. Laboratory results for zoo animals were also reviewed for 2004-2010 to assess the occurrence of potential zoonotic infections. Veterinary clinic, animal handler, grounds, maintenance and administrative staff participated in the surveys, with 49, 42 and 46 participants in the 1991, 2002 and 2010 surveys, respectively (29% of total zoo staff in 2010). A small number of staff reported work-related infections, including erysipelas (1), giardiasis (1) and campylobacteriosis (1). The seroprevalence of antibodies to hepatitis A virus and Toxoplasma gondii closely reflected those in the Auckland community. No carriage of hepatitis B virus (HBV) was detected, and most of those with anti-HBV antibodies had been vaccinated. Few staff had serological evidence of past leptospiral infection. Three veterinary clinic staff had raised Chlamydophila psittaci antibodies, all < 1 : 160 indicating past exposure. Two staff (in 1991) had asymptomatic carriage of Giardia lamblia and one person (in 2010) had a dermatophyte infection. After 1991, positive tests indicating exposure to Mycobacterium tuberculosis were < 10%, comparable to the general New Zealand population. Zoo animals had infections with potential zoonotic agents, including G. lamblia, Salmonella spp., Campylobacter spp. and T. gondii, although the occurrence was low. Zoonotic agents pose an occupational risk to zoo workers. While there was evidence of some zoonotic transmission at Auckland Zoo, this was uncommon and risks appear to be adequately managed under current policies and procedures. Nevertheless, ongoing assessment of risk factors is needed as environmental, human and animal disease and management factors change. Policies and procedures should be reviewed periodically in conjunction with disease monitoring results for both animals and staff to minimise zoonotic transmission.

Influence of poverty and infection on asthma in Latin America.

PURPOSE OF REVIEW: Asthma in Latin America is a growing public health problem and seems to be most prevalent and cause most morbidity among poor urban populations. This article will review the findings of recent human studies of the associations of asthma prevalence in Latin America with factors associated with poverty and inequality including childhood infections, stress, environment, nutrition and diet. RECENT FINDINGS: Most asthma in childhood in Latin America is nonatopic and has been associated with exposures related to environmental dirt, diet and psychosocial distress. These factors are strongly linked to poverty and inequality. Interestingly, infections with bacterial, viral and parasitic pathogens in childhood appear to attenuate atopy in childhood but have no effect on asthma symptoms. There are biologically plausible mechanisms by which dirt exposures (e.g. endotoxin and other microbial products and nonmicrobial irritants), diet and obesity and psychosocial stress may cause airways inflammation. SUMMARY: Most childhood asthma in Latin America is nonatopic for which important risk factors are those of poverty including poor hygiene (i.e. dirt), poor diet and obesity and psychosocial stress. There is evidence that exposures to infections in early childhood reduce atopy but not asthma. Research is needed to identify causes of nonatopic asthma that may be suitable for primary prevention or other public health intervention strategies for asthma in Latin America.

Primer reporte de pseudomiasis intestinal humana por Eristalis tenax (Diptera, Syrphidae) en zona semiárida urbana del estado Falcón, Venezuela / First report of human intestinal pseudomiasis by Eristalis tenax (Diptera, Syrphidae) in urban semiarid area from Falcon state, Venezuela

Pseudomiasis es el término empleado cuando se considera que las larvas y/o huevos de moscas se adquieren accidentalmente per os y atraviesan con inmediatez a lo largo del tracto digestivo. Se documenta un caso de una pseudomiasis intestinal por larvas de Eristalis tenax (Diptera: Syrphidae) en una paciente femenina de 39 años de edad, proveniente de un sector periférico de la ciudad de Coro, estado Falcón, Venezuela. La paciente observó inmediatamente la presencia de la larva viva en sus heces. Aunque refirió sufrir eventualmente de cólicos, al examen físico se presentó normal. La paciente aparentemente no sufre de trastornos mentales, y posee un nivel socioeconómico bajo. El presente trabajo constituye el primer reporte documentado de una pseudomiasis entérica por E. tenax en la zona semiárida del estado Falcón, en la región nor-occidental de Venezuela.

Pseudomyiasis is the term used for the accidental entrapment of swallowed fly maggots and/or eggs immediately passing through the digestive tract. We report a case of intestinal pseudomyasis caused by the larvae of the cosmopolitan drone fly Eristalis tenax (Diptera: Syrphidae) in a 39 year old woman, resident in a suburban sector from Coro city, Falcon state, Venezuela. The patient immediately noticed a living larva in her stool. Although patient referred eventually became colic, her physical examination was normal, with no mental disturbance. She was in a low socioeconomic level. This is the first report of an enteric pseudomyasis by E. tenax in the semiarid zone of Falcon state, in the northwestern region of Venezuela.