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At least 1,027 records · Page 57Linked to original sources
PubMed2003

Chronic lung sepsis: lung abscess, bronchiectasis, and empyema.

Chronic lung infections including lung abscess, bronchiectasis, and empyema remain serious medical diseases despite the availability of antimicrobial agents. Recent publications contribute to our understanding of disease pathogenesis and management of these entities. The microbial pathogen of lung abscess may be different comparing immunocompetent with immunocompromised patients, supporting a concept for aggressive diagnostic investigations and targeting of specific potential pathogens. The use of surgery in bronchiectasis may be declining, but surgical intervention remains an important strategy with favorable outcomes, especially in cases of focal bronchiectasis. For empyema, maintaining a high index of clinical suspicion may allow for diagnostic thoracentesis in patients with pleural effusions and allow initiation of appropriate tube thoracotomy drainage and use of fibrinolytics. With appropriate management, morbidity and mortality may be limited and outcomes generally favorable.

Anti-Bacterial Agents↗
PubMed2006

Incidence and pathogenic effect of Streptococcus pseudopneumoniae.

We evaluated the incidence of Streptococcus pseudopneumoniae in clinical isolates by phenotypic methods and DNA-DNA hybridization. The pathogenic role of this organism was investigated with the mouse peritonitis/sepsis model. Our results show a low incidence (1/120 pneumococcal isolates) and a potential pathogenic effect for S. pseudopneumoniae.

Animals↗
PubMedDate not supplied

[The factors of bacterial pathogenicity and their role in the development of the infectious process].

The latest data concerning the characterization of the pathogenicity factors of bacteria and the evaluation of their role in the realization of definite phases of the development of the infectious process are presented. The infectious process is regarded as the result of the complicated simultaneous interaction of microorganisms and different cells and tissues of the host body. The problems of the polydeterminant character of pathogenicity factors, tho possibility of the joint action of different factors at one and the same stage of the development of the infectious process and, vice versa, the action of the same factors at different stages of the interaction of the infective agent and the susceptible host are discussed. Modern data on the genetic control of pathogenicity factors, on the localization of their genetic determinants on the chromosome and the virulence plasmids, information of pathogenicity "islets" which jointly determine the pathogenic potential of the infective agent are given. The emphasis is made on fact that the general principle of the genetic control of bacterial pathogenicity is complicated relationship between chromosomal and nonchromosomal determinants; some of them form a part of genetic pathogenicity "islets", simultaneously regulating and expressing the pathogenicity factors of the infective agent.

Bacteria↗
PubMedDate not supplied

Bacterial survival on radiographic cassettes.

The purpose of this investigation was to report the life span of Escherichia coli, Enterococcus faecalis and Staphylococcus aureus on 3 types of radiographic imaging receptors currently used in diagnostic imaging departments in the United States. Kodak 400 speed, Dupont 400 speed and Fuji computed radiography cassettes were inoculated with the 3 bacteria, then placed in an incubation cabinet and cultured for a period of 2 weeks. All 3 cassettes revealed confluent growth with no noticeable reduction in bacterial numbers for the entire test period. This study verifies that common potentially pathogenic bacteria can survive for prolonged periods on radiographic imaging cassettes. Therefore, effective cleaning regimens are of fundamental importance in controlling and preventing potential nosocomial transmission in the diagnostic imaging department.

Enterococcus faecalis↗
PubMed2004

Mutations in the neurofilament light chain gene (NEFL)--a study of a possible pathogenous effect.

Neurofilaments (NFs) have been shown to be involved in the molecular pathology of numerous neurode-generative human disorders. Recently a set of mutations in the neurofilament light gene (NF-L) was reported in patients suffering from axonal and demyelinating forms of Charcot-Marie-Tooth disease (CMT1 and CMT2). Although a few of the NEFL gene sequence variants have been shown to be rather pathogenous mutations than harmless polymorphisms, the status of some of these variants remains unclear. The aim of this study was to analyse a potential pathogenous effect of the mutations in the NEFL gene identified in CMT affected patients.

Charcot-Marie-Tooth Disease↗
PubMed2005

[The pathogenicity of amoebae-resisting chlamydiales].

During the last 15 years, several new bacterial species related to Chlamydia have been discovered within amoebae. Their ability to grow within these professionnal phagocytes suggests that they are also resistant to destruction by other phagocytic cells such as alveolar macrophages and that they may be excellent candidates as new agents of pneumonia. There are growing evidence that these Chlamydia-like organisms play a role as etiological agent of lower respiratory tract infections. Thus, Parachlamydia is apparently an agent of inhalation pneumonia and--at least in the immunocompromised host--of community-acquired pneumonia, whereas Simkania is considered as a common agent of bronchiolitis and an emerging agent of pneumonia. Nevertheless, their pathogenic potential remains underestimated since these obligate intracellular bacteria grow only poorly or not at all on the culture media generally used to detect pathogen in diagnostic laboratories.

Amoeba↗
PubMed2006

Environment arrays: a possible approach for predicting changes in waterborne bacterial disease potential.

Current molecular techniques for identifying bacteria in water have proven useful, but they are not reliably predictive of impending disease outbreaks. Genomics-based approaches will help to detect the presence of pathogens quickly and well before they grow into a population that poses a risk to public health. We suggest that genomics is only one component of the toolbox that will be needed to identify emerging waterborne threats. We propose a methodology beyond genomics, based on activity in the mobile genome. This approach makes use of a new device called an environment array. The array will depend upon the same research necessary for genomics-based detection, but will not require an a priori knowledge of virulence genes. Environment arrays are assembled from molecular profiles of the infectious elements that transfer between bacteria. The advantage of the array is that it monitors the activity of the mobile genome, rather than the presence of particular DNA sequences. Environmental arrays should thus be many times more sensitive than traditional hybridization or PCR-based techniques that target already-known DNA sequences. Mobile elements are known to respond to new environmental conditions that may correlate with a chemical contamination or the bloom of bacterial pathogens, potentially allowing for a much broader application in detecting unknown or unanticipated biological and chemical contaminants.

Bacteria↗
PubMed1975

Vibrio parahaemolyticus -- a marine pathogen detected in South African coastal waters.

Vibrio parahaemolyticus has been detected in the Natal and Eastern Cape costal water of South Africa. As a proven cause of gastro-enteritis or a potential pathogen to humans, it is an organism of importance to public health. Outlines of the history, pathogenicity and identification are given, as well as the results of the local investigation of this organism.

Culture Media↗
PubMed2006

The generation and modulation of antigen-specific memory CD8 T cell responses.

The immune system has adapted to effect different mechanisms to combat the multitude of potential pathogens in our environment. In particular, CD8 T cells are participants in the immune response to intracellular pathogens, which include viruses, certain types of bacteria, and protozoa. Classified as members of the adaptive immune system, antigen-specific CD8 T cells after activation eventually form a pool of memory. Memory cells have an enhanced ability to protect against subsequent infections. The generation of antigen-specific CD8 T cells, therefore, is a potential approach in the design of vaccines, especially for those pathogens in which the humoral response is insufficient to protect the host.

Animals↗
PubMed2001

Etiology of children's diarrhea in Montevideo, Uruguay: associated pathogens and unusual isolates.

We studied microorganisms associated with infant diarrhea in a group of 256 children admitted to a public pediatric hospital in Montevideo, Uruguay. Diagnostic procedures were updated to optimize detection of potential pathogens, which were found in 63.8% of cases, and to be able to define their characteristics down to molecular or antigenic type. Coinfection with two or more agents was detected in more than one-third of positive studies. Escherichia coli enteric virotypes, especially enteropathogenic E. coli (EPEC), were shown to be prevalent. Rotavirus, Cryptosporidium, Campylobacter (mainly Campylobacter jejuni), and Shigella flexneri were also often identified. Enterotoxigenic E. coli, Salmonella, and Giardia lamblia were sporadically recognized. Unusual findings included two enteroinvasive E. coli strains, one Shigella dysenteriae 2 isolate, and a non-O:1 Vibrio cholerae culture. EPEC bacteria and S. flexneri (but not Salmonella) showed unusually frequent antimicrobial resistance, especially towards beta-lactam antibiotics, which is the subject of ongoing work.

Animals↗
PubMed2003

Regulation of dendritic cell function by microbial stimuli.

Dendritic cells (DC) initiate T cell responses and produce cytokines and other molecules that can regulate the class adaptive immunity. It is increasingly clear that DC in vivo are in a "resting" state and require exogenous signals to transit into an "effector" state in which they can prime T cells. Much of this DC activation process appears to be regulated by infection. Exposure of murine DC to certain pathogens or their products triggers DC migration to T cell areas of secondary lymphoid tissues, improves MHC presentation and increases DC co-stimulatory potential. Pathogen recognition can also initiate cytokine production and/or condition DC to produce cytokines in response to subsequent T cell feedback signals delivered via CD40 and similar receptors. Recognition of pathogens by DC is largely dependent on Toll-like receptors (TLRs). Interestingly, mouse splenic CD8alpha+ and CDalpha-CD4- DC have the ability to produce either IL-12 p70 or IL-10 depending on the nature of the pathogen encountered. In contrast, CD4+ DC seem incapable of producing IL-12 p70. Thus, the nature of the pathogen can dictate the type of cytokine that is made by some DC subsets, allowing them to prime distinct types of immune responses. Overall, DC display significant plasticity in their ability to respond to infection and direct adaptive immunity.

Animals↗
PubMed1992

Isolation of Mycobacterium simiae from the environment.

An examination of 18 sphagnum samples collected in two different biotopes of the coastal region of southeastern Madagascar revealed an unexpectedly high positivity for mycobacteria (83.3%). The concentration of alcohol acid-fast bacilli reached a high level of 10(5) and 10(6)/g, respectively, compared with the sphagnum biotopes in moderate climates. Besides the habitat-specific mycobacterial species in sphagnum vegetation, like M. sphagni, M. gordonae and M. madagascariense, potentially pathogenic species, like M. avium, M. scrofulaceum and M. xenopi and M. marinum, were found. Furthermore, pathogenic M. simiae was found in sphagnum vegetation of Madagascar, first time isolated in the environment until now. It should be considered as a potential source of infection for human and animals.

Animals↗
PubMed2000

Thirteen novel mutations of the replicated region of PKD1 in an Asian population.

BACKGROUND: Mutations of PKD1 are thought to account for approximately 85% of all mutations in autosomal dominant polycystic kidney disease (ADPKD). The search for PKD1 mutations has been hindered by both its large size and complicated genomic structure. To date, few mutations that affect the replicated segment of PKD1 have been described, and virtually all have been reported in Caucasian patients. METHODS: In the present study, we have used a long-range polymerase chain reaction (PCR)-based strategy previously developed by our laboratory to analyze exons in the replicated region of PKD1 in a population of 41 unrelated Thai and 6 unrelated Korean families with ADPKD. We have amplified approximately 3.5 and approximately 5 kb PKD1 gene-specific fragments (5'MR and 5'LR) containing exons 13 to 15 and 15 to 21 and performed single-stand conformation analysis (SSCA) on nested PCR products. RESULTS: Nine novel pathogenic mutations were detected, including six nonsense and three frameshift mutations. One of the deletions was shown to be a de novo mutation. Four potentially pathogenic variants, including one 3 bp insertion and three missense mutations, were also discovered. Two of the nonconservative amino acid substitutions were predicted to disrupt the three-dimensional structure of the PKD repeats. In addition, six polymorphisms, including two missense and four silent nucleotide substitutions, were identified. Approximately 25% of both the pathogenic and normal variants were found to be present in at least one of the homologous loci. CONCLUSION: To our knowledge, this is the first report of mutation analysis of the replicated region of PKD1 in a non-Caucasian population. The methods used in this study are widely applicable and can be used to characterize PKD1 in a number of ethnic groups using DNA samples prepared using standard techniques. Our data suggest that gene conversion may play a significant role in producing variability of the PKD1 sequence in this population. The identification of additional mutations will help guide the study of polycystin-1 and better help us to understand the pathophysiology of this common disease.

Amino Acid Sequence↗
PubMed2005

Microbial flora of tears of orthokeratology patients, and microbial contamination of contact lenses and contact lens accessories.

PURPOSE: The purpose of this study is to determine if there are changes in the ocular flora of overnight orthokeratology (ortho-k) patients, and the levels of contamination of their lenses and lens accessories, and to correlate compliance with levels of contamination. METHOD: Normal ocular flora of 41 subjects was determined twice before commencing ortho-k lens wear by culture of the lower conjunctiva. Further specimens were collected on six follow-up visits after beginning lens wear, as were samples from their lenses, cases, and suction holders. A questionnaire on lens care was administered after the fifth visit. RESULTS: Three subjects provided conjunctival samples yielding Staphylococcus aureus on one occasion before lens wear, one being positive for this organism after beginning lens wear. Of 38 subjects yielding no growth or only normal eye flora before use, 28 remained free of ocular pathogens after beginning lens wear. Only four subjects had positive cultures on more than one occasion after lens wear. There was no significant difference in isolation levels of pathogens with lens wear (p = 0.423). Lens culture of 54% of subjects yielded no growth or normal flora only; lenses of 16 subjects yielded potential pathogens, including three subjects contaminated on more than one occasion. Lens isolates did not match the organisms transiently colonizing the eye. Lens case, the most frequently contaminated item, was associated with lens contamination (p < 0.001), the same organism being isolated from both items in 11 subjects. Lens suction holder was less frequently contaminated. Neither lens case nor suction holder contamination was associated with isolates from the eye. Reported good compliance correlated with lack of contamination in all but one subject. The most frequent breaches in the lens care protocol were failure to clean, disinfect, and replace the lens case. CONCLUSION: Ocular flora was not altered by ortho-k lens wear over an extended period, and patients remained free of infection. Contaminants identified were generally of a transient nature. Most patients had significant contamination of at least one item, most frequently the lens case. Lens case isolates were significantly associated with those from the lens. The majority of patients reporting good compliance had low or no contamination of their lenses and accessories.

Adolescent↗
PubMed2004

Bacterial colonization of laryngectomy stomas.

Infections with organisms resistant to conventional antibiotics are of increasing concern. This observational study investigates the bacterial colonization of the peristomal area of laryngectomy patients. Thirty-two consecutive patients who had previously undergone laryngectomy were recruited from the Head and Neck Clinic of a teaching hospital. Swabs were taken from the laryngectomy stoma site, the mouth and both nasal cavities. Microbiological culture and isolation were performed following standard procedures. Despite no clinical sign of infection, 27 patients were found to be carriers of one or more organism (84.4 per cent). Staphylococcus aureus was detected in the peristomal area of 15 patients (46.9 per cent). Methicillin-resistant Staphylococcus aureus (MRSA) was isolated in seven (21.9 per cent) cases. In this series the authors found a high incidence of colonization with potentially pathogenic bacteria in laryngectomy stomas with no clinical signs of infection. In a significant number of patients, Gram positive organisms were identified that could potentially cause cellulitis or wound infections.

Aged↗
PubMed1995

Chronic relapsing experimental autoimmune encephalomyelitis with a delayed onset and an atypical clinical course, induced in PL/J mice by myelin oligodendrocyte glycoprotein (MOG)-derived peptide: preliminary analysis of MOG T cell epitopes.

Myelin basic protein (MBP) and proteolipid protein (PLP), the most abundant proteins of central nervous system (CNS) myelin, have been extensively studied as possible primary target antigens in multiple sclerosis (MS), a primary demyelinating autoimmune disease of the CNS. However, there is increasing evidence to suggest that autoimmune reactivity against the quantitatively minor myelin component, myelin oligodendrocyte glycoprotein (MOG), can also play a role in the pathogenicity of MS. We recently demonstrated a predominant response to MOG by peripheral blood lymphocytes from patients with MS tested for their reactivity against various myelin antigens, including MBP and PLP. To ascertain whether or not T cell reactivity to MOG in MS is a potentially pathogenic response, we have tested the ability of synthetic MOG peptides (pMOG) representing potential T cell epitopes, to induce neurological disease in mice. Both strains of mice tested (SJL/J and PL/J mice) were able to mount a primary T cell response to some of the five MOG peptides synthesized, pMOG 1-21, 35-55, 67-87, 104-117 and 202-218. T cell lines could be raised in both strains to pMOG 35-55 and 67-87, but epitope definition revealed that each strain recognized a different minimal epitope within these two peptides. T cell lines to pMOG 1-21 and 202-218 could also be raised in SJL/J and PL/J mice, respectively. T cell reactivity to pMOG 104-117 was not observed in either mouse strain. None of the peptides tested induced detectable clinical signs in SJL/J mice. In contrast, an MS-like chronic relapsing-remitting disease could be induced in PL/J mice with pMOG 35-55. The disease presented with a delayed onset and with clinical signs which differed significantly in their progression and expression from the typical ascending paralysis of experimental autoimmune encephalomyelitis induced with other myelin components, such as MBP and PLP. Histological examination of CNS tissue from mice injected with pMOG 35-55 revealed only mild neuropathological signs with few inflammatory foci in brain and spinal cord. Some myelin splitting and edema were detected upon electron microscopic examination in the spinal cord and cerebellum. Transfer of pMOG 35-55 reactive T cells into naive PL/J mice resulted in pathological changes characterized by inflammatory foci in the brain and spinal cord. This passively induced disease was clinically silent, as was also reported for Lewis rats injected with T cells specific for the same MOG peptide.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMedDate not supplied

Virulence factors associated with Escherichia coli present in a commercially produced competitive exclusion product.

In this study, we assessed the pathogenic potential of Escherichia coli associated with a commercial competitive exclusion (CE) product by examining the phenotypic characteristics associated with E. coli virulent for humans and domestic animals. Most E. coli isolates were capable of proliferating in iron-deplete chicken sera. Interestingly, none of the E. coli isolates from the commercial CE product contained the bacterial adhesin Tsh characteristic of avian pathogenic E. coli associated with airsacculitis and colisepticemia. In terms of virulence potential for humans, most E. coli isolates (78%) were sensitive to killing by 12.5% human sera. Because of their sensitivity to human sera, the E. coli in the CE product are not likely to cause a serious systemic infection in humans and, therefore, do not present a risk of causing septicemia in humans. Because these isolates also lack the gene tsh, they are also less likely to cause systemic disease or airsacculitis in poultry than pathogenic strains commonly isolated from diseased birds.

Adhesins, Escherichia coli↗
PubMed2005

AGE-RAGE and AGE Cross-link interaction: important players in the pathogenesis of diabetic kidney disease.

At present, diabetic kidney disease affects about 15 - 25% of all type 1 diabetic patients and 20 - 40% of all patients with type 2 diabetes. The mechanisms underlying the development of diabetic kidney disease are extremely complex and not yet fully understood. Among the many potential pathogenic mechanisms responsible for the progression in diabetic kidney disease, the involvement of metabolic factors beyond blood glucose (such as advanced glycation end products (AGEs)) has been suggested. This review will present the emerging evidence in support of a significant role of AGE formation in the development of diabetic kidney disease. AGEs mediate their effects through two main pathways - through a receptor-independent AGE cross-link formation pathway and through a receptor-dependent pathway where AGEs bind to specific cell surface associated receptors, the receptor for AGE (RAGE) being the most well-characterised so far. First, we will describe the AGE-RAGE system, including its localisation in the normal kidney, and then move on to discuss in vitro and in vivo studies (that is, experimental and clinical data) in support of a pathogenic role of AGE-RAGE and AGE cross-link interaction in the development of diabetic kidney disease. Finally, the effects of known and potential inhibitors of AGE-RAGE and AGE cross-link systems in diabetic kidney disease will be examined.

Animals↗