Littérature scientifique sur le sujet « Invasive micro-organism »

Urinary tract infections (UTIs) caused by Haemophilus parainfluenzae represent a very small percentage of this kind of pathology in children, and it has scarcely been described in the medical literature. According to previous studies of over 800 urine samples in children under 15 years old, a decrease of 50 % (from 0.13 % to 0.07 %) is estimated in its occurrence over the last two decades. This can be explained by the early detection of UTIs and their early empirical treatment, because this micro-organism shows high sensitivity to antibiotics. Also, the culture media in which this bacterium grows are not included in most current protocols. Here we report a case of a UTI caused by H. parainfluenzae in a 4-year-old boy.

Aim: To study synergistic effect of clove and cinnamon extract against oral pathogens- an in vitro study Materials And Method: The plant extract was prepared using 1g of cinnamon and 1g of clove added to 10 ml of distilled water. Placed in the heating mantle for about 20 minutes for condensation and was stored in a centrifuged tube. Using miller hinton agar, the organism was lawn cultured, later well cut cut and dined in micro plate. About 50µl of sample was used, and the micro plate was incubated for 24 hrs at room temperature (37°c) and the zone of inhibition was measured. Conclusion: Cinnamon and Clove extract has considerable synergistic effect against Streptococcus mutans and Enterococcus and a new tool for minimally invasive and adhesive dentistry avenues.

We report a case of severe community-acquired pneumonia caused by Streptococcus pyogenes (Lancefield Group A streptoccocus) that was complicated by a streptococcal toxic shock syndrome. Although this micro-organism is an uncommon cause of community-acquired pneumonia, previously well individuals may be infected and the clinical course may be fulminant. A household contact was the likely point of infection. Invasive group A streptococcal disease continues to remain an important cause of morbidity and mortality in the community and therefore will continue to be encountered by intensive care physicians. Treatment of Group A streptococcal infection remains penicillin; however, clindamycin should be added in severe infection.

Objectives: To study the micro flora in wounds of the burn patients from three tertiary care medical hospitals in Karachi. Introduction: In burn patient infections arise from multiple sources and infect burn wounds by a variety of micro-organisms. Gram negative bacterial infection results from translocation from colon, further more burn patients are infected by Hospital acquired bacteria by various invasive and non invasive procedures. Period: July 2002 to December 2002. Setting: This study was conducted at the Department of Microbiology, Basic Medical Sciences Institute, Jinnah Postgraduate Medical Centre, Karachi. Study Design: Observational study. Material & Methods: A retrospective study of fifty five patients with burn wound infection was carried out at burn units of Civil Hospital Karachi, National Institute of Child health Karachi and Abbasi Shaheed Hospital, Karachi. Patients who received burn injuries with clinical signs and symptoms of infection were included in this study. Results: In the present study 46(29%) isolates of P. aeruginosa were recovered, in which most strains were MDR and their sensitivity against Imipenem was 38 (78%). The over all prevalence of the Oxidase negative Gram negative coli form bacteria was more than 70%, in which the most prevalent organism belongs to Proteus Spp;(27%) follows the Enterobacter Spp;.(15.5%). Conclusions: Bacteria belongs with family Enterobacteriacae were more prevalent i.e. >70% while P. aeruginosa was individually more prevalent than any member of family Enterobacteriacae and was most resistant to multiple antibiotics than any other bacteria. Imipenem was the most effective drug against all gram negative bacteria follows the 4th. generation Cephalosporin Cefepime.

Corynebacterium diphtheriae is a well-known cause of localized respiratory tract infections. However, this micro-organism can also be associated with invasive infections, such as endocarditis, septic arthritis and osteomyelitis. Invasive infections are often caused by non-toxigenic strains. To set up an in vivo experimental model of C. diphtheriae infection, mice were infected intravenously with different doses (ranging from 1×107 to 5×108 bacteria per mouse) of three non-toxigenic strains, namely ISS-4749, ISS-4746 and ISS-3319. Similar mortality rates were observed with the three strains, with an LD50 ranging from 9×107 to 1·2×108. All strains were arthritogenic, although to different extents. ISS-4749 and ISS-4746 infection resulted in a maximum of 60 and 50 %, respectively, of animals with articular lesions, while in the ISS-3319-infected group only 25 % were positive. There were differences in systemic and joint cytokine production in the three experimental groups. ISS-4749- and ISS-4746-infected mice exhibited higher local levels of interleukin (IL)-6 and IL-1β than ISS-3319-infected animals. At systemic levels, ISS-3319 was able to induce early and sustained production of interferon-γ (IFN-γ), but not IL-6. Conversely, infection with the other strains resulted in high IL-6, but not IFN-γ, production. In conclusion, an experimental model of C. diphtheriae infection was set up, with development of septic arthritis. This model could be useful in studies on the pathogenicity and characterization of virulence factors other than toxin production.

Abstract Frogs and toads are incredible reservoirs of biologically active peptides. Amphibians secrete host defense peptides from their skin as part of their innate immune response. This ancient response acts to protect the amphibians against microbes. The quantity and scope of these secreted peptides dwarfs mammalian analogues, accounting for a substantial portion of all known host defense peptides. The non-invasive and non-harmful methods for frog peptide collection, in tandem with the abundance and breadth of these peptides, makes them excellent choices for novel peptide drug therapies. Studies have shown that these peptides can effectively neutralize enveloped viruses, mycobacteria, gram-negative and gram-positive bacteria, fungi, and even cancerous or transformed cells. Because of the nature of antimicrobial peptides, often targeting the most critical, conserved aspects of a micro-organism, they may prove a vital alternative to conventional drugs plagued by pathogen resistance. Given this untapped potential for anti-viral therapies, we assessed novel host defense peptides from the skin of the Indian fungoid frog, Hylarana malabarica. During our analysis, we isolated several peptides from H. malabarica that show anti-viral activity against human influenza viruses. Our studies indicate that peptides from H. malabarica demonstrate anti-influenza activity in vitro, and also show potential as an anti-viral therapy in vivo.

The pyelonephritis is the most frequent disease of urinary system in children with long current and process synchronization. Up to the present time, the scientific studies on the effectiveness of pelotherapy at the chronic pyelo-nephritis in children with ecological burdened history aren’t carried out; there are no methods of its application for this population group of patients. 40 children, aged 7-14 years, with chronic pyelonephritis in ecological burdened history were examined. In the complex Spa treatment, the pelotherapy was held traditionally on the lumbar region or developed adaptive-reflex technique. The advantage of the proposed approach to pelotherapy been proven that confirmed the best elimination of the complaints of patients and more pronounced dynamics of the signs of micro-hematuria, pyuria, oxaluria and recovery antichristianity ability urine on calcium phosphates in all patients. In comparison with the conventional treatment, the proposed technique is less invasive and more adequate, providing a gradual and consistent involvement of various reflex zones, which is important in violation of the adaptation processes in patients with ecologo-hygienic history. In addition, it is proved that the appointment of mud applications on a delicate mode contributes to the stimulation of protective forces of an organism, mainly through regulatory and training effects on various systems of the child´s body, without causing general and local pathological reactions.

To increase the productivity of animals and reduce the cost of production, it is necessary to provide animals with a sufficient and high-quality level of feeding, to keep animals in appropriate conditions, to carry out high-quality and timely disinfection, which will lead to a decrease in pathogenic micro flora in the premises where animals are kept, there will be a break in the epizootic chain of disease spread. In modern animal husbandry, which is characterized by a significant accumulation of animals on a limited area, increased requirements for the quality and ecological products, and the prevention of infectious, invasive and especially anthropozoonous diseases, the leading place is occupied by disinfection. It is one of the most important directions in the complex of measures to combat infectious diseases, which prevents significant economic losses as a result of infection. Disinfection is also the cheapest, most availiable and highly effective method of disease prevention. The disinfectant market of Ukraine has a wide range of simple and complex preparations that can be used for disinfection. However, most of them do not meet modern requirements regarding solubility, activity against a wide range of microorganisms, the influence on biofilms of microorganisms, formation of resistance, anti-corrosion activity, the influence on the organism, environmental safety, universality. Among the new biocidal preparations used in human and veterinary medicine and which most fully meet the modern requirements for disinfecting properties, the leading place is occupied by polymeric compounds of guanidine, in particular polyhexamethyleneguanidine (PHMG). This preparation is an effective solution to the problem of combating infectious diseases that cause significant economic losses not only in animal husbandry, but also at the medical and ecological level. PHMG does not have a cumulative, sensitizing, irritating or skin-resorptive action. Disinfectants with polyhexamethyleneguanidine have a prolonged action and show the activity under conditions of changing pH, have long-term storage and are stable during transportation, can be used in various ways (spraying, watering, wiping, dipping, soaking, pouring, etc.), after use they form films with a long-lasting bactericidal effect, they can be disinfected in the presence of animals and people.

Introduction: Helicobacter pylori colonization of the human gastric mucosa potentially leads to chronic gastritis that may progress to peptic ulcer disease. Additionally, this micro-organism has been identified as a risk factor for the development of gastric carcinoma and gastric lymphoma. Its relation with non-ulcer dyspepsia has not been clear. Objective: To assess the diagnostic usefulness of stool antigen test with serum Helicobacter pylori antibody and CLO test in the diagnosis of Helicobacter pylori infection in dyspeptic patients. Materials and Methods: This was a cross sectional study was conducted in the Department of Microbiology, Sylhet M.A.G. Osmani Medical College in collaboration with the Department of Gastroenterology Sylhet M.A.G. Osmani Medical College, Sylhet from July 2012 to June 2013. The calculated sample size was 196 but in this study we took 150 patients due to financial constrain and time limitation. Patients upper GI tract for dyspepsia and whoever fulfilled the inclusion and exclusion criteria were considered as study sample. All the findings, previous history and reports of investigations were recorded in a preformed data collection sheet prepared for this purpose. The patient with clinical features suggestive of dyspepsia was selected for upper GI endoscopy. Results: For this purpose, 150 dyspeptic patients fulfilling the inclusion and exclusion criteria were enrolled. The age of the patients ranged from 18 to 80 years with the mean age of 43.35 (SD ± 16.30) years. There were 32 (21.3%) patients in the age group of 21 to 30 years, 31 (20.7%) patients in the age group of 31 to 40 years, 30 (20.0%) patients in the age group of 41-50 years, 26 (17.3%) patients in the age group of 51-60 years, 21 (14.0%) patients in the age group of above 60 years and 10 (6.7%) patients in the age group up to 20 years. There were 93 (62.0%) male and 57 (38.0%) female with a ratio of male to female was 163:1. Showed the distribution of patients according to endoscopic findings. Endoscopic findings was normal in 85 (56.7%) patients, duodenal ulcer in 26 (17.3%) patients, gastritis in 23 (15.3%) patients, and gastric ulcer in 16 (10.7%) patients. The distribution of patients according to CLO test. CLO test was positive in 97 (64.7%) patients and negative in 53 (35.3%) patients. The patients according to serum Helicobacter pylori antibody by ELISA. Serum Helicobacter pylori antibody was positive in 101 (67.3%) patients and negative in 49 (32.7%) patients. Stool antigen test was positive in 73 (48.7%) patients and negative in 77 (51.3%) patients. Using CLO test as the gold standard the sensitivity and specificity of stool antigen test in the diagnosis of Helicobacter pylori infection was 72.7% and 94.3% respectively. Positive and negative predictive values were 95.9% and 64.9% respectively. The overall accuracy was 80.0%. There was moderate agreement between the two test (Kappa, k=0.603; p<0.001). Using CLO test as the gold standard in the diagnosis of Helicobacter pylori infection the sensitivity and specificity of serum Helicobacter pylori antibody was 89.7% and 82.2% respectively. Positive and negative predictive values were 86.1% and 79.6% respectively. The overall accuracy was 84.0%. There was a substantial agreement between the two test (Kappa, k=0.644; p<0.001). Conclusion: The overall accuracy was 80.0%. There was good agreement between the two test (Kappa, k=0.603). Using CLO test as the gold standard in the diagnosis of Helicobacter pylori infection this study showed that the sensitivity and specificity of serum Helicobacter pylori antibody was 89.7% and 82.2% respectively. Positive and negative predictive values were 88.7% and 100.0% respectively. The overall accuracy was 84.0%. In conclusion comparing CLO test (invasive) is still the superior to stool antigen and serology (non-invasive), both of which is going very close to each other in the diagnosis of Helicobacter pylori infection in dyspeptic patients.

Legionella pneumophilais an environmental micro-organism capable of producing an acute lobar pneumonia, commonly referred to as Legionnaires’ disease, in susceptible humans. Legionellae are ubiquitous in aquatic environments, where they survive in biofilms or intracellularly in various protozoans. Susceptible humans become infected by breathing aerosols laden with the bacteria. The target cell for human infection is the alveolar macrophage, in which the bacteria abrogate phagolysosomal fusion. The remarkable ability ofL pneumophilato infect a wide range of eukaryotic cells suggests a common strategy that exploits very fundamental cellular processes. The bacteria enter host cells via coiling phagocytosis and quickly subvert organelle trafficking events, leading to formation of a replicative phagosome in which the bacteria multiply. Vegetative growth continues for 8 to 10 h, after which the bacteria develop into a short, highly motile form called the ‘mature form’. The mature form exhibits a thickening of the cell wall, stains red with the Gimenez stain, and is between 10 and 100 times more infectious than agar-grown bacteria. Following host cell lysis, the released bacteria infect other host cells, in which the mature form differentiates into a Gimenez-negative vegetative form, and the cycle begins anew. Virulence ofL pneumophilais considered to be multifactorial, and there is growing evidence for both stage specific and sequential gene expression. Thus,L pneumophilamay be a good model system for dissecting events associated with the host-parasite interactions.

L’efficacia di PCR quantitativa basata su una sonda TaqMan specifica per il genere è stata confermata come preciso strumento di rilevamento di DNA di Phytophthora su suolo artificialmente infettato, in suolo di invasatura contaminato proveniente da vivaio ed in campioni di trappole aeree. Nessuna quantificazione di DNA è avvenuta dopo due settimane dalla morte indotta del patogeno e, in confronto con i metodi di isolamento tradizionali, è stata dimostrata una significativa maggiore efficienza come strumento diagnostico. La fluttuazione stagionale di Phytophthora in aria è stata quantificata e descritta per il periodo di campionamento. La tecnica di sequenziamento 454 è stata utilizzata per identificare la tassonomia delle specie di Phytophthora in un hotspot biologico in Western Australia ed al fine di descrivere la patogenicità delle due specie sequenziate con maggior frequenza è stato realizzato un esperimento in serra. Le tecniche di laboratorio utilizzate in questo studio hanno fornito nuove nozioni sull’ecologia di Phytophthora. La PCR quantitativa basata su sonda TaqMan è testata e proposta come efficace strumento di prevenzione verso l’arrivo di specie invasive. Importanza dell’impatto di questo studio L’efficienza della gestione di Phytophthora dipende dalla conoscenza delle caratteristiche patogene di gruppi ristretti di specie o di una singola specie . Ricerche come queste forniscono le basi scientifiche per comprendere l’epidemiologia di una malattia ed applicare un controllo risolutivo. A quantitative PCR technique based on a genus specific TaqMan probe was confirmed as a precise method for detecting Phytophthora DNA in artificially infested soil under laboratory condition, in naturally infested soil and tissues of potted nursery plants and in the filters of air traps. No positive DNA quantification occurred in soil after two weeks from pathogen induced death and a significant higher efficiency as diagnostic tool was demonstrated compared to traditional isolation methods both in soil and plant tissues. Seasonal fluctuation of aerial spread of Phytophthora was also quantified and described. A 454 sequencing approach was used to identify the Phytophthora species present in a biological hotspot area in Western Australia, and a glass house experiment was performed in order to describe the pathogenicity traits of the two most frequently detected species. The lab procedures used in this study provided a more precise knowledge of Phytophthora ecology. The quantitative PCR assay based on designed TaqMan probe was demonstrated to be very efficient and is proposed as a reliable early detection instrument of prevention against the income of invasive species. Efficient management of Phytophthora depends to the knowledge of pathogenicity traits in restrict groups or single species. Investigations like those presented in this thesis contribute the scientific bases to understand the epidemiology of disease and to apply a successful control.

This chapter introduces the “biohybrid systems” section of the Handbook of Living Machines and briefly reviews some important examples of systems formed by coupling biological to engineered components. These include brain–machine interfaces, both non-invasive, using different external measurement and scanning devices, and invasive approaches focusing on implantable probes. Next we consider fabrication methods for micro- and nanobiohybrid systems and an example of a biohybrid system at the organism level, in the form of a robot–animal biohybrid, developed using methods from synthetic biology. There are many application for biohybrid systems in healthcare: we include exemplar chapters describing intelligent prostheses such as artificial hands with tactile sensing capabilities, sensory organ–chip hybrids in the form of cochlear implants, and artificial implants designed to replace damaged neural tissue and restore lost memory function.

Infection by a pathogenic micro-organism triggers a coordinated activation of both innate and adaptive immune responses. The innate immune response quickly triggers an antimicrobial response that will initiate development of a pathogen-specific, long-lasting adaptive immune response. Accurate recognition of microbial-associated molecular patterns by pattern-recognition receptors (PRRs) is the cornerstone of this immediate response. Most studied PRRs are Toll-like receptors (TLRs) and their kinase signalling cascades that activate nuclear transcription factors, and induce gene expression and cytokine production. Deficiencies or genetic variability in these different signalling pathways may lead to recurrent pyogenic infections and severe invasive diseases. After initial contact between the host and pathogen, numerous factors mediate the inflammatory response, as pro-inflammatory cytokines and chemokines. Apart from host genetic variability, pathogen diversity also influences the phenotypic features of various infectious diseases. Genomic analysis may assist in the development of targeted therapies or new therapeutic strategies based on both patient and microorganism genotype.

The gastro-intestinal tract (GIT) hosts the most numerous and diverse reservoir of microbes in humans. There is increasing interest in the relationship between the GIT microbiome and human health. Obesity, diabetes, allergy, and a number of inflammatory diseases have been linked with the human GIT microbiome. Infections of the GIT arise either as a result of a change in the relationship between the commensal microbes colonizing the GIT (endogenous infection) or entry in to the GIT of a micro-organism which causes disease (exogenous infection). Commensals most commonly invade host tissues as a result of compromised defensive barriers. Disease associated with exogenous infection can be toxin-mediated, or associated with local or systemic invasion of the host. Endogenous infections are usually polymicrobial. In the mouth the aetiology, presentation, and anatomical associations have led to the description of a number of syndromes. Peritonsillar infection with involvement of the internal jugular vein is Lemierre’s syndrome, which is particularly associated with infection with Fusobacterium necrophorum. ‘Trench mouth’ is a severe form of ulcerative gingivitis, so named because in the absence of oral hygiene it was a relatively common diagnosis among those in the trenches during the First World War. Ludwig’s angina is a severe infection of the floor of the mouth which spreads in to the submandibular and sub-lingual space, often following a tooth-related infection. Deep neck infections are more common in children than adults and can involve the parapharyngeal, retropharyngeal, peri-tonsillar, or sub-mandibular spaces. Children with deep neck infections are more likely than adults to present with cough and respiratory distress. Oesophagitis has a wide range of potential aetiologies. Fungi (particularly Candida species) are probably the most common microbial cause of oesophagitis. Fungal infection of the distal oesophagus is thought to play an important role in the pathogenesis of disseminated fungal infection. Risk factors for fungal infection include poor oral intake, exposure to antibiotics, immunocompromise (HIV, steroids, cancer treatments), gastric acid suppressants, and damage to mucosal integrity (naso-gastric tubes, acid reflux, varices). Bacteria (including Mycobacteria, Actinomycetes, Treponemes), parasites, and viruses (herpes simplex, cytomegalovirus) are rarer infectious causes of oesophagitis.