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Results for “pathogenicity classification”

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PubMed1981

A statistical test for classification, with applications to the characterization of pathogens according to antibiotic susceptibility patterns.

If n different analytical procedures are applied to a culture of a pathogen, then that pathogen is characterized by an ordered sequence or vector of length n. A group of such sequences (or 'susceptibility patterns' as they are called in this context) can be generated by applying this process to cultures taken from infected individuals in an epidemic. This paper introduced statistical tests that can be used to determine whether a pattern obtained from the culture of a single case differs from those patterns obtained from cultures of a group of infected individuals. The methods are applied to come nosocomial epidemics. These taxonomic techniques extend beyond the present application to other classification problems in the biological and medical sciences.

Anti-Bacterial Agents↗
PubMed2025

Pathogenicity assessment of genetic variants identified in patients with severe hypertriglyceridemia: Novel cases of familial chylomicronemia syndrome from the Dyslipidemia Registry of the Spanish Atherosclerosis Society.

PURPOSE: Genetic testing is required to confirm a diagnosis of familial chylomicronemia syndrome (FCS). We assessed the pathogenicity of variants identified in the FCS canonical genes to diagnose FCS cases. METHODS: 245 patients with severe hypertriglyceridemia underwent next-generation sequencing. Preliminary variant pathogenicity criteria and classification, based on the American College of Medical Genetics and Genomics guidelines, were obtained online and verified. Phenotype evaluation was based on lipoprotein lipase activity deficiency, a clinical score, and/or type I hyperlipoproteinemia determined in 25 patients. RESULTS: Twenty-four biallelic variants were analyzed. Evidence-based criteria allowed the reclassification of 8 likely pathogenic (LP) variants in the LPL, APOA5, and LMF1 genes into pathogenic (P) and the change of 2 variants of uncertain significance (VUS) to LP. Conversely, 2 variations in LMF1 remained as VUS. Additionally, 1 variant in LPL and 2 in GPIHBP1 were likely benign. Twenty FCS cases had biallelic P/LP variants and 1 patient, with an FCS phenotype, harbored biallelic VUS. FCS was excluded from 4 patients with pathogenic/likely benign combinations. CONCLUSION: The analysis of the clinical and biochemical features of patients with variants in the FCS canonical genes allowed a confident variant classification that helped in the diagnosis of novel FCS cases.

Humans↗
PubMed1993

Proteolytic enzymes of pathogenic and non-pathogenic strains of Acanthamoeba spp.

The aim of this work was biochemical characterization and classification of proteinases in pathogenic and non-pathogenic strains of Acanthamoeba spp. The authors showed two proteinase (acid 35 kDa and alkaline 65 kDa) which could be separated electrophoretically. Acid proteinase was inhibited by serine proteinase inhibitors such as DIFP. The second enzyme which was active at alkaline pH, was enhanced by EDTA and inhibited by iodoacetate (IAA) and (p-CMB) p-chloromercuribenzoate. These substances are known to inhibit cysteine type proteinases. The alkaline proteinase was more distinctively active in pathogenic strains and belongs to cysteine class (EC 3.4.22), whereas the acid proteinase was similar active in pathogenic and non-pathogenic strains and belong to serine class (EC 3.4.21).

Acanthamoeba↗
PubMed1996

Interpretive criteria for antimicrobial susceptibility testing of ceftiofur against bacteria associated with swine respiratory disease.

Ceftiofur, an extended-spectrum cephalosporin, is active against a variety of animal pathogens, including organisms associated with swine respiratory disease. However, minimum inhibitory concentration (MIC) breakpoint and disk diffusion interpretive criteria have not been established for swine pathogens. Susceptibility tests were performed by broth microdilution MIC and disk diffusion methods on 246 bacterial species that cause swine respiratory disease. Ceftiofur was active against Salmonella sp., Pasteurella multocida, Actinobacillus pleuropneumoniae, Streptococcus suis, and Escherichia coli but was not active against Bordetella bronchiseptica measured by MIC. Based on pharmacokinetic studies of ceftiofur in swine after a single intramuscular injection of 3 or 5 mg/kg body weight of ceftiofur and on the MIC and disk diffusion data, we recommend MIC breakpoints and disk diffusion distances, respectively, of < or = 2 micrograms/ml and > or = 21 mm for susceptible, 4 micrograms/ml and 18-20 mm for intermediate, and > or = 8 micrograms/ml and > or = 17 mm for resistant classification for swine pathogens. When these breakpoints were applied to data from a previous study using bovine pathogens, only 1 minor interpretive error occurred.

Actinobacillus pleuropneumoniae↗
PubMed1989

Evolutionary relationship between luteoviruses and other RNA plant viruses based on sequence motifs in their putative RNA polymerases and nucleic acid helicases.

Comparative studies of sequence motifs in the RNA polymerases and nucleic acid helicases of positive-sense RNA plant viruses have provided a new scheme for the classification of these pathogens. We propose a new luteovirus supergroup which should be added to the already described Sindbisvirus-like and picornavirus-like supergroups. Sequence motifs of nucleic acid helicases and RNA polymerases which previously were considered to be specific for each of the two supergroups now occur together within this new supergroup. We propose that this new viral supergroup provides an evolutionary link between the other two supergroups.

Amino Acid Sequence↗
PubMed1996

Optimal treatment of urinary tract infections in elderly patients.

Elderly patients are at high risk for urinary tract infection (UTI). Infections of the urinary tract may be classified as asymptomatic bacteriuria, uncomplicated cystitis, uncomplicated pyelonephritis or complicated UTI. The micro-organisms responsible for causing UTI are largely predictable and dictate therapy when indicated. UTIs may be diagnosed by both nonculture and culture techniques. Asymptomatic bacteriuria, though quite common in the elderly, should rarely be treated. Treatment of symptomatic uncomplicated and complicated UTIs is largely dictated by the known or expected pathogen(s) and classification of the infection. Additional features affecting the treatment of UTI in the elderly include allergies, adverse reactions to therapy, drug interactions and modification for renal insufficiency.

Aged↗
PubMed1991

[Effect of cyclic nucleotides on beta-lactamase production and outer membrane proteins of clinical Xanthomonas maltophilia isolates].

Resistance of clinical Xanthomonas maltophilia isolates to beta-lactam compounds is influenced considerably by the nutrient medium employed for sensitivity testing; the organisms were much more resistant to beta-lactams when susceptibility testing was performed in Mueller-Hinton broth as compared to Isosensitest broth as the nutrient medium. Consequently, the influence of cyclic nucleotides was studied on beta-lactamase expression and outer membrane proteins in more detail. The exogenous supply of 5 mmol/l c-AMP or its lipophilic derivative c-AMP-N6,O2-dioctanoyl resulted in a marked reduction of enzyme production as compared to the control assay; 0.5 mmol/l c-AMP-S or 1 mmol/l c-GMP did not exhibit any effect. The analysis of the outer membrane proteins of Xanthomonas maltophilia revealed the single band of a 40 kdal protein which was expressed independently of the experimental conditions, thus confirming the classification of this pathogen as Xanthomonas maltophilia. The reduction of beta-lactamase expression in the presence of either c-AMP or c-AMP-N6,O2-dioctanoyl cannot be explained at present. The above findings emphasize again the problem of in-vitro susceptibility testing. To avoid false sensitive results, the use of Mueller-Hinton broth is recommended.

Bacterial Outer Membrane Proteins↗
PubMed1980

[New contributions to the etiology of insulin-dependent diabetes (author's transl)].

The present studies on the possible factors that can be implicated in the etiopathogenesis of diabetes are reviewed. The association between insulin-dependent diabetes and certain specifications of the HLA system are commented on, as well as the experimental studies and the clinical observations which indicate the possible relationship between this disease and some viruses. The role played by autoimmunity is thoroughly discussed, specially the significance of anti-pancreatic islet antibodies. Finally, new pathogenic theories and classifications of the disease are proposed.

Autoantibodies↗
PubMed1975

Tears of the peripheral retina; pathogenesis, incidence and classification in autopsy eyes.

A pathogenic analysis of full-thickness tears of the peripheral retina and their incidence in autopsy eyes is presented. Tears were classified according to their location (ora or postora, quadrant and zone), type of traction (zonuloretinal or vitreoretinal), morphological features (flap or operculum), presence or absence of posterior vitreous detachment, and their association with other ocular lesions. Tears were present in 2% of eyes. They were postoral in 92%, uniformly distributed in the quadrants, in the equatorial zone in 95%, related to vitreoretinal traction in 94%, of the flap type in 64%, accompanied by posterior vitreous detachment in 79% and were significantly more prevalent in eyes with lattice degeneration (17%). A simple classification of postoral tears is recommended which incorporates these pathogenic principles and includes three types according to their topographical relationship to the vitreous base: intrabasal--caused by avulsion of zonular traction tufts; juxtabasal--related to traction of the posteriorly detached vitreous on irregularities in posterior border of vitreous base; extrabasal--resulting from avulsion of cystic retinal tufts.

Adult↗
PubMedDate not supplied

In vivo evaluation of the pathogenicity of field isolates of infectious bronchitis virus.

The pathogenicity of 13 field isolates of infectious bronchitis virus (IBV) isolated from Georgia broiler farms from 1989 to 1992 was evaluated using the IBV and Escherichia coli mixed-infection model. Based on the clinical signs, mortality, and lesions, the isolates were classified as high, intermediate, and low in pathogenicity. The in vivo classification was compared with the serotype classification results obtained by reverse transcriptase-polymerase chain reaction-restriction fragment length polymorphism analysis. The high-pathogenicity group was composed of five isolates representing three serotypes: Arkansas, Georgia variant (GAV), and Massachusetts. Isolates in the intermediate- and low-pathogenicity groups were all representatives of the Connecticut serotype, except for one isolate, which belonged to the Massachusetts serotype.

Animals↗
PubMedDate not supplied

[Biochemical and serological characterization of "Bacillus sphaericus" strains, pathogenic or non-pathogenic for mosquitoes (author's transl)].

A biochemical and serological study of 35 Bacillus sphaericus strains including some pathogenic for mosquito larvae, is reported. A classification of these, and a differentiation of the pathogenic strains, cannot be made on the basis of the 78 phenotypic characters which have been determined by conventional methods. Numerical analysis of the results given by the auxanograms on 160 substrates, gives good results. An even more valuable approach is the flagellar agglutination technique, which clearly distinguishes the pathogenic from the non-pathogenic strains and furthermore can specifically differentiate strains among the pathogenic isolates.

Animals↗
PubMed1994

[An unusual cervical tumor: meningioma. Apropos of a case of petrous origin. Review of the literature of meningioma presenting as cervical mass].

Primary ectopic meningiomas are uncommon. The authors report a case of a 12-year-old boy with a meningioma presenting as a neck mass. The conclusion of the initial biopsy was chemodectoma, but on surgical resection, the tumour was found to have invaded the petrous bone. Post-operative follow-up was uneventful but magnetic resonance imagery revealed extension to the cerebello-pontine angle, the cavernous sinus, the tentorium and the falx. The authors discuss the main pathogenic hypotheses and the classification of ectopic meningiomas. Based on 62 similar cases reported in the literature, primary ectopic meningiomas are found most often in young subjects, with no female predominance, neurofibromatosis is often observed and angioblastic or malignant features are frequent. These tumours can be divided into 6 localizations (jugulo-carotid space, lymph nodes, parotid gland, thyroid gland, soft paravertebral tissues, skin) and into 3 pathogenic groups (solitary ectopic tumour of the neck, tumour of the neck connected to a cranial or spinal meningioma, metastasis). Meningioma of the jugulo-carotid space with connection to the skull base is the most frequent entity. Solitary ectopic meningiomas of the neck occur in only 1 out of 5 cases. In 2 out of 3 cases, the neck localization involves a connection to a cranial or spinal meningioma. In a few cases the neck mass is a metastasis. These findings suggest that a complete neuroradiological work-up is required. Prognosis depends on the completeness of the surgical resection and the histologic aggressiveness frequently encountered.

Child↗
PubMed1990

[Etiologic interpretation of acute intestinal diseases].

The authors suggest a scheme for the detection of the etiologic factor of an acute intestinal condition; this scheme permits detecting dysbiotic changes in the microbiocenosis, finding pathogenic or opportunistic microorganisms in fecal culture. Classification of acute intestinal diseases into those induced by pathogenic and opportunistic microorganisms, as well as those resultant from acute imbalance of the normal ratio of intestinal bacteria helps carry out differential therapy of patients. The results of such bacteriologic studies may be useful for epidemiologists.

Acute Disease↗
PubMed1993

Chronic fatigue syndrome: influence of histamine, hormones and electrolytes.

The chronic fatigue syndrome is poorly understood. We believe the underlying causes in many atopics and women are a persistent infection and hypersensitivity to the immune-suppressive effects of histamine and certain pathogens. We believe much to the symptomatology can be explained by all four types of hypersensitivity (Gell and Coombs classification) in reaction to a pathogen, electrolyte disturbances which include sometimes permanent changes in cell membranes' ability to pass electrolytes, sometimes permanent biochemical changes in mitochondrial function, and disturbances of insulin and T3-thyroid hormone functions. We also explain in detail what 'fatigue' means for these patients. We present evidence from the medical literature for the plausibility of our hypotheses.

Electrolytes↗
PubMed1988

Etiological agents of bovine mastitis.

A total of 137 microbial species, subspecies and serovars have been isolated from the bovine mammary gland. Nucleic acid hybridization studies have restructured the classification of many mastitis pathogens. Availability of defined species descriptions has permitted greater insight into the distribution and pathogenicity of many previously unrecognized microorganisms associated with bovine mastitis. Precise epidemiological studies are needed to better delineate the role of some microorganisms in bovine mastitis and to aid development of improved control methods.

Animals↗