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PubMed1994

Ribotyping of Erwinia chrysanthemi Strains in Relation to Their Pathogenic and Geographic Distribution.

16S and 23S rRNAs from Escherichia coli were used to study the relationship among a representative collection of strains of Erwinia chrysanthemi differing in their original host and geographical origin. Phenetic analysis of restriction fragment length polymorphisms allowed the distribution of the studied strains into seven clusters. These clusters were similar to those obtained by cladistic methods and appeared to correlate well with the established pathovars and biovars but to a lesser extent with geographical distribution. Except for two groups of strains defined as tropical and temperate isolates (clusters 3 and 4, respectively), our clustering correlated well with botanical classifications of host plants. However, the rRNA groupings were shown to be more discriminative than biovar analysis. To assess the relationship between rRNA clusters and pathogenicity, 12 representative strains from different clusters were tested for pathogenicity on different plants. The two typical symptoms, maceration and wilting, were observed for these strains. The occurrence of the tobacco hypersensitivity reaction for a subset of these strains is discussed in light of recent results concerning the presence of an hrp gene. Considering symptom expression only, rather than the capacity for plant infection, strains from the same cluster were shown to induce similar symptoms in test plants. Thus, since host specificity is still quite controversial, rRNA patterns may constitute a useful tool in taxonomic and epidemiological studies of Erwinia chrysanthemi species.

Journal Article↗
PubMed2005

Acute bacterial prostatitis: two different sub-categories according to a previous manipulation of the lower urinary tract.

Acute bacterial prostatitis (ABP) (NIH Category I), has not undergone any modification in the update of prostatitis classification. ABP was diagnosed in 614 patients in our centre over 9 years (1993-2001). We analyse the clinical pattern of ABP and the role of bladder outlet obstruction in its etiology, as well as whether two different ABP sub-categories could be defined as a function of a history of previous manipulation of the lower urinary tract. The results of the study show that the clinical pattern of a patient suffering from ABP does not differ from the statements of previous publications. On the other hand, patients with ABP have been shown to present with no bladder outlet obstruction. Finally, this study has disclosed the fact that the cases of ABP elicited by previous manipulation of the lower urinary tract (10%) show a different pattern from those cases where no previous manipulation has occurred (90%). The patients with ABP secondary to manipulation are older, have a higher risk of prostate abscess and higher frequency of multiple infections and also infections by pathogens other than Escherichia coli. Due to all of these reasons, it would be advisable to subdivide category I within the classification of prostatitis.

Acute Disease↗
PubMed1994

Lupus nephritis. Classification, prognosis, immunopathogenesis, and treatment.

There is great variation in the characteristics of renal histology, in its clinical expression and clinical course, and, most likely, in the pathogenic mechanisms of glomerular damage. As the ability to more precisely characterize these lesions improves and as we better understand the multiple pathogenic mechanisms and modulating factors at play in the disease, treatment advances and improved renal survival should follow.

Antibodies, Antinuclear↗
PubMed1978

Studies on growth inhibition by lectins of Penicillia and Aspergilli.

It has previously been shown in our laboratory that wheat germ agglutinin (WGA) binds to Trichoderma viride and inhibits growth of this fungus. Here we report on the effect of WGA, soybean agglutinin (SBA) and peanut agglutinin (PNA) on Penicillia and Aspergilli. Binding of the lectins to the fungi was examined with the aid of their fluorescein isothiocyanate (FITC) conjugated derivatives. FITC-WGA bound to young hyphal walls of all species, in particular to the hyphal tips and septa, in agreement with the chitinous composition of the cell walls of the two genera. Hyphae of all species examined were labelled, though in different patterns, by FITC-SBA and FITC-PNA, suggesting the presence of galactose residues on their surfaces. Young conidiophores, metulae (of the Penicillia), vesicles (of the Aspergilli), sterigmata and young spores, were also labelled. The three lectins inhibited incorporation of [3H]acetate, N-acetyl-D-[3h]glucosamine and D-[14C]galactose into young hyphae of Aspergillus ochraceus, indicating interference with fungal growth. Inhibition of spore germination by the three lectins was also observed. Preincubation of the lectins with their specific saccharide inhibitors prevented binding and the inhibitory effects. We conclude that lectins are useful tools for the study of fungal cell surfaces, and may also serve as an important aid in fungal classification. The present findings also support the suggestion that one role of lectins in plants is protection against fungal pathogens.

Aspergillus↗
PubMed1991

The contribution of non-MHC genes to susceptibility to autoimmune diseases.

Genetic studies of experimental models of autoimmune diseases, including systemic lupus-like syndromes and organ-specific autoimmunity, provide major information on genetic control of autoimmune diseases. In addition to genes known to be linked to the major histocompatibility complex (MHC), these studies point to multiple genes located outside the MHC that influence the onset and the progression of autoimmune diseases. Identification of these genes and of their interrelationships is now a major task that will be facilitated by recent progress in molecular biology and gene mapping. Among candidate genes, antigen-receptor genes (i.e., immunoglobulin- and T-cell receptor genes) most likely contribute an important part of the autoimmune susceptibility in several of these animal models. Available linkage data suggest a similar involvement of these antigen-receptor genes in several human autoimmune diseases. In addition to a better understanding of pathogenic mechanisms associated with autoimmunity, the knowledge of these disease-predisposing genes is expected to permit a better classification of often complex syndromes as well as the design of new treatments.

Animals↗
PubMed1994

Remarkable sequence relatedness in the DNA encoding the major outer membrane protein of Chlamydia psittaci (koala type I) and Chlamydia pneumoniae.

DNA encoding the major outer membrane protein (MOMP) of the koala type-I strain of Chlamydia psittaci (pathogen responsible for blindness and infertility in koalas) was cloned and sequenced. Comparison with momp gene sequences from other chlamydial species revealed a remarkable degree of homology (> 97%) with that of the human pathogen, Chlamydia pneumoniae. In comparison, the sequence only shared 75% DNA sequence homology with other C. psittaci members and 69% homology with C. trachomatis. The open reading frame consisted of 1167 bp encoding a 389-amino acid (aa) pre-MOMP including a leader sequence of 23 aa, similar to the C. pneumoniae gene. These genes were closely related even within the four variable domains (86-100% homology). Specific antibodies were capable of distinguishing between koala type I and C. pneumoniae. This very high degree of relatedness between C. pneumoniae, a human pathogen, and an individual strain of C. psittaci in the momp gene raises further questions on the host specificity, classification and evolutionary relationships of the different chlamydial species.

Amino Acid Sequence↗
PubMed2005

Rational monoclonal antibody development to emerging pathogens, biothreat agents and agents of foreign animal disease: The antigen scale.

Many factors influence the choice of methods used to develop antibody to infectious agents. In this paper, we review the current status of the main technologies used to produce monoclonal antibodies (mAbs) from the B cells of antigen-sensitized animals. While companies are adopting advanced high-throughput methods, the major technologies used by veterinary and medical research laboratories are classical hybridoma fusion and recombinant library selection techniques. These methods have inherent advantages and limitations but have many common aspects when using immunized rodents. Laboratories with expertise in both methods of antibody development have a distinct advantage in their ability to advance mAb technology. New and re-emerging infectious threats in today's world emphasize the need for quality immunoreagents and the need to maintain expertise in mAb development. We provide examples of some common applications for mAb reagents used to identify pathogens such as the SARS-coronavirus (SARS-CoV), Bacillus anthracis, and foot-and-mouth disease (FMD) virus. We also outline a framework for investigators to make rational decisions concerning which method to use to develop mAbs based upon characteristics of the pathogen under study and the intended downstream application. Lastly, we provide parameters for the immunisation of mice and a classification system which describes the expected outcome for mAb development strategies when using classes of immunogens to generate mAbs with desired activities.

Animal Diseases↗
PubMed1998

Otitis media in children with vertically-acquired HIV infection: the Great Ormond Street Hospital experience.

Human immunodeficiency virus (HIV) infection continues to be a vexing problem in the pediatric population. Otitis media, a common entity in immunocompetent as well as immunocompromised children, is prevalent in pediatric patients with HIV infection. Recurrent infections and complications secondary to otitis media are also common in this population. The purpose of this review was to evaluate the records of a large group of children with HIV infection undergoing treatment for otitis media at a tertiary care center. Incidence of infections, severity of infections, and pathogens responsible were the key points of data collection in relation to each patient's HIV clinical and immunologic classification. We reviewed 72 patients with vertically-acquired HIV infection undergoing treatment at the Hospital for Sick Children, Great Ormond Street, London. All patients were born to HIV infected mothers of sub-Saharan African origin. A total of 32 (44.4%) of these children presented to our institution with one or more episodes of otitis media, six of whom suffered systemic complications secondary to middle ear pathology. Middle ear culture data, when available from actively draining ears, was similar to those of immunocompetent children in the general population. The most common complications were systemic bacteremia and recalcitrant infections requiring intravenous antibiotic therapy. Severity of immunosuppression was associated with higher incidence and severity of otitis media. Otitis media in an HIV infected child must be treated aggressively at its outset in an attempt to minimize possible complications. Administration of prophylactic antibiotics to these children may reduce the frequency of acute and chronic infections. Improvement in immunologic status using antiretrovirals or protease inhibitors is a primary goal in diminishing the severity of otitis media as well as other infections in these children.

AIDS-Related Opportunistic Infections↗
PubMed2003

Trends in enteric disease as a cause of death in the United States, 1989-1996.

The authors examined rates of and trends in enteric disease as a cause of death in the United States. The National Center for Health Statistics Multiple Cause of Death databases for 1989-1996 were analyzed for International Classification of Diseases, Ninth Revision, codes for gastroenteritis due to infectious agents and codes describing illness with other enteric pathogens. The highest rates of death related to enteric diseases were seen among people older than 75 years, followed by children under 1 year of age. Rates increased markedly over time in the 65- to 74-year age group for bacterial enteric pathogens and in the 35- to 44-year age group for viral enteric pathogens. Enteric diseases were the underlying cause of death for an average of 2,740 deaths during each year of this study, and the rate of death due to enteric-related disease is increasing.

Adolescent↗
PubMed1999

[Pneumocystis carinii is still a dangerous opportunist. The infection is continuously a threat to immunocompromised patients].

Despite recent decrease in the incidence of Pneumocystis carinii pneumonia (PCP) among patients infected with HIV (human immunodeficiency virus), PCP remains a threat to other categories of immunocompromised patients. The article provides an outline of recent, mainly molecular genetic, findings in P. carinii research, including its new classification as a primitive fungus, host specificity and verified de novo infection in HIV-infected subjects. As the pathogen still defies propagation in vitro, laboratory diagnosis is dependent on microscopic demonstration of the organism. Diagnostic specificity can be enhanced by generating specific PCR (polymerase chain reaction) products which can be sequenced for genotyping. Findings in animal studies and epidemiological observations (e.g., in outbreaks of PCP among immunocompromised hospital patients), suggest transmission of PCP infection to be airborne. Genetic methods have been used to study the mode of P. carinii transmission. Nucleic acids of the human form of P. carinii (P. carinii f. sp. hominis) have been detected in the air of hospital wards, indicating susceptible patients to be at risk. By contrast, findings obtained with the same methods in studies of person-to-person transmission of P. carinii among clustered cases of PCP in hospitals suggest infection to be environmentally acquired. Thus, many questions remain to be answered regarding the occurrence and transmission of P. carinii infection.

AIDS-Related Opportunistic Infections↗
PubMed2006

Initial experiences with novel therapy for pulmonary hypertension in Slovakia.

Pulmonary hypertension (PH) is the most serious and potentially devastating chronic disorder of the pulmonary circulation with diverse etiologies and pathogenesis characterized by abnormal increased vasoconstriction and vascular remodelling. Current specific therapy of PH is based on an understanding of its pathogenesis and is acting through pathogenic pathways and therefore changes therapeutic strategy, effectively improves clinical course and prolongs life. The authors discuss the actual classification, pathogenesis in short and particularly actual treatment modalities and the impact on the natural history of this disorder. In chronic thromboembolic pulmonary hypertension is pulmonary endarterectomy if correct indicated the curable method, warranted substantial improvement of life quality and survival. These novel therapies of PH were absent in Slovakia until recently. The authors present initial experiences, results of PH management up to date on the basis of cooperation with PH centres in Austria and Czech Republic (Tab. 1, Fig. 6, Ref. 32).

Adult↗
PubMed2026

Tree Killer, Qu'est-ce Que C'est? Insights From Forest Pathogen Genomes.

Forests are central to planetary health but are increasingly challenged by emerging diseases driven by climate change, global trade, and anthropogenic disturbance. Despite the apparent resilience of long-lived, genetically diverse tree hosts, forest ecosystems have repeatedly experienced landscape-level pathogen-driven transformations. Advances in genomics, transcriptomics, and functional biology have transformed our understanding of how fungal and oomycete pathogens interact with their hosts across a continuum of lifestyles, from saprotrophy and necrotrophy to biotrophy. Here, we synthesize insights from comparative and population genomics and functional studies across diverse forest pathosystems to examine the traits that characterize successful tree pathogens. We highlight how lifestyle plasticity, adaptations to woody tissues, vector-mediated transmission, and biotrophic stealth enable pathogens to colonize perennial hosts and persist over long temporal scales. We further examine how genome plasticity, hybridization, and horizontal gene transfer generate adaptive potential that often outpaces host evolutionary responses under current environmental change. Finally, we discuss emerging genomic tools, including biosurveillance, machine learning-based classification, and genome editing, that are beginning to link genotype to phenotype and inform assessments of disease risk. By integrating genomic, ecological, and evolutionary perspectives, this review outlines general principles governing forest pathogen success and identifies priorities for future research aimed at improving understanding, early detection, and management of forest diseases in a changing world.

Trees↗
PubMed1983

Entomogenous Fusarium species.

Fusarium species are known for their abundance in nature and their diverse associations with both living and dead plants and animals. Among animals Fusarium is found primarily in relationship with insects. This literature review of the past 50 years includes both non-pathogenic and pathogenic relationships between Fusarium and insects. Special attention is given to the host range, particularly between plant- and insect-hosts, and to the possible microbial potential of the fungus to control insect pests. Correct classification of this fungus has been difficult because of its diverse and non-uniform morphological features. However, by now a usable and reliable taxonomic system has been developed. The fungus can be easily cultured and mass produced. Among the non-pathogenic associations mutualism and allotrophy are found between Fusarium and wood-inhabiting and flour beetles, respectively, enhancing development and production of beetle larvae. Some insects contribute to the dispersal of the fungus in the environment by means of spore passage through their guts. Plant-pathogenic Fusarium species gain access to host tissue by plant-feeding insects. A large number of Fusarium spp. are entomopathogenic; some are weak, facultative pathogens, especially of the lepidopteran and coleopteran orders, and they will colonize their dead hosts as saprophytes. In a few cases pathogenicity to both plant and insect by one isolate was found. Strong pathogens were reported primarily from homopterans and dipterans from field observations of natural mortalities as well as from pathogenicity tests. Potential Fusarium isolates which cause high insect mortalities also show high host specificity and no damage to crop plants. The question of host invasion has been addressed by few investigators. Entrance of the fungus via the oral route, oviposition tubes, wounds, or ectoparasitic activity, were stated, but no claim for penetration of the insect cuticle. Mycotoxins, such as trichothecenes (T-2) and other secondary metabolites, contributed to mortalities of termites, mealworms, flour beetles, maize borers and blow flies, while zearalenone (F-2) exhibited a beneficial effect on egg production in flour beetles and a detrimental effect on fecundity in mammals. Studies on adverse effects of the fungus on beneficial organisms (including mammals and plants) revealed that both harmful as well as safe Fusarium isolates exist in nature. Highly host-specific and strongly entomopathogenic Fusarium isolates should be more extensively studied and tested for their possible use in biological control.

Animals↗
PubMed1981

The diagnosis and classification of gastritis and duodenitis.

There are specific and nonspecific categories of gastritis and duodenitis. In each category, the mucosal pattern may be erosive or nonerosive. Specific refers to distinctive patterns of inflammation associated with defined clinical syndromes. These are rare in the stomach and include granulomatous disorders and hypertrophic gastropathies. In the duodenal bulb they include Crohn's disease and any other disorder that may affect the proximal small bowel. Endoscopy diagnoses nonspecific erosive disease of the stomach and duodenal bulb. Histology diagnoses nonspecific, nonerosive gastritis (NNG) and duodenitis (NND). The major interest in NNG and NND is in their potential as pathogenic risk factors for other disorders. Although NNG and NND may theoretically cause symptoms, provocative tests need to be devised to prove this. Confusion in the classifications of NNG and NND often arises because clinicians, radiologists, endoscopists, and pathologists use similar terms to mean different things.

Biopsy↗
PubMed1990

Development of a new classificatory model of malingering.

Inclusion criteria for the classification of malingering are shaped and largely predetermined by our explanatory theories. Current theories have postulated the motivation to malinger is either the product of underlying psychopathology (pathogenic model) or criminal backgrounds (DSM III-R model). I have proposed a third model that malingering is typically an adaptive response to adverse circumstances which may best be understood in the context of decision theory. Based on this approach I have argued that indices of malingering should be empirically derived and focused on clinical presentation. Finally, I have proposed a preliminary model for the classification of malingerers which combines clinical data with corroborative evidence.

Antisocial Personality Disorder↗
PubMed2006

[A multicentre study on the pathogenic agents in 665 adult patients with community-acquired pneumonia in cities of China].

OBJECTIVE: To investigate the pathogenic causes of community-acquired pneumonia (CAP) in adult patients in China, the relation of previous antibiotic use and the Pneumonia Patient Outcome Research Team (PORT) classification to microbial etiology, and the prevalence of drug resistance of common CAP bacteria. METHODS: A prospective study was performed on 665 consecutive adult patients with CAP at 12 centers in 7 Chinese cities during one year. The etiology of pneumonia was considered if one of the following criteria was met: (1) valid sputum sample yielding one or more predominant strains; (2) blood cultures yielding a bacterial pathogen; (3) seroconversion, a > or = 4-fold increase or decrease titers of antibodies to Mycoplasma pneumoniae, Chlamydia pneumoniae and Legionella pneumophila. Minimum inhibitory concentration (MIC) of respiratory tract isolates was determined using the agar dilution method. RESULTS: Pathogens were identified in 324/610 patients (53.1%) with valid serum samples and sputum cultures as follows: Mycoplasma pneumoniae (126, 20.7%), Streptococcus pneumoniae (63, 10.3%), Haemophilus influenzae (56, 9.2%), Chlamydia pneumoniae (40, 6.6%), Klebsiella pneumoniae (37, 6.1%), Legionella pneumophila (31, 5.1%), Staphylococcus aureus (23, 3.8%), Escherichia coli (10, 1.6%), Moraxella catarrhalis (8, 1.3%), Pseudomonas aeruginosa (6, 1.0%). Of 195 patients with a bacterial pathogen, an atypical pathogen was identified in 62 (10.2%) cases. The non-susceptibility rate of Streptococcus pneumoniae to penicillin, azithromycin, and moxifloxacin was 20.3%, 75.4% and 4.3% respectively. CONCLUSIONS: Atypical pathogens have important role in CAP, with Mycoplasma pneumoniae being the most common pathogen, and mixed infection of atypical pathogens with bacteria was found in 10.2% of the cases. Streptococcus pneumoniae and Haemophilus influenzae remain the most important bacteria for CAP. More than 75.0% of Streptococcus pneumoniae was resistant to macrolides and 20.3% was resistant to penicillin.

Adult↗
PubMed2000

New classification and update on the quinolone antibiotics.

The newer fluoroquinolones have broad-spectrum bactericidal activity, excellent oral bioavailability, good tissue penetration and favorable safety and tolerability profiles. A new four-generation classification of the quinolone drugs takes into account the expanded antimicrobial spectrum of the more recently introduced fluoroquinolones and their clinical indications. First-generation drugs (e.g., nalidixic acid) achieve minimal serum levels. Second-generation quinolones (e.g., ciprofloxacin) have increased gram-negative and systemic activity. Third-generation drugs (e.g., levofloxacin) have expanded activity against gram-positive bacteria and atypical pathogens. Fourth-generation quinolone drugs (currently only trovafloxacin) add significant activity against anaerobes. The quinolones can be differentiated within classes based on their pharmacokinetic properties. The new classification can help family physicians prescribe these drugs appropriately.

Anti-Infective Agents↗
PubMed2001

Biopersistence of synthetic mineral fibers as a predictor of chronic intraperitoneal injection tumor response in rats.

In December 1997 the European Commission (EC) adopted Directive 97/69/EC (O.J. L 343/19 of 13 December 1997), in which criteria were established for the classification and labeling of synthetic mineral fibers. This directive was derived based upon an extensive program evaluating current scientific knowledge on fiber pathogenicity and its relationship to the biopersistence of long fibers. Within this context, the biopersistence of fibers longer than 20 microm was found to be a good predictor of the lung burden and early pathological changes in chronic inhalation studies with fibers as well as of the tumor response in chronic intraperitoneal studies with fibers. The analysis that provided the scientific basis for the relationship of biopersistence to the chronic intraperitoneal (ip) results is presented in detail. Analysis of the relationship of biopersistence clearance half-times to ip tumor response shows a statistically significant relationship of ip tumor response to not only the number of fibers injected, but also the median length of the fibers injected and their solubility (clearance half-time). The results show that the biopersistence half-times as determined by intratracheal instillation (T(1/2) of WHO fibers or weighted T(1/2) of fibers with L > 20 microm) and as determined by inhalation (weighted T(1/2) of fibers with L > 20 microm) are equivalent predictors of the ip results. From these ip studies, fibers that can be exonerated from classification as carcinogens in Europe have a relative tumorigenic potency in the ip cavity of between 66 and 2500 times less than fibers that have been shown to produce a significant increase in tumors following chronic inhalation exposure. In addition, based upon the ip results, there is no statistical difference between the EC and the other fiber exoneration criteria, such as the German Gefahrstoffverordnung of 1999.

Animals↗