Evaluation of the Statistical Detection of Change Algorithm for Screening Patients with MS with New Lesion Activity on Longitudinal Brain MRI.

BACKGROUND AND PURPOSE: Identification of new MS lesions on longitudinal MR imaging by human readers is time-consuming and prone to error. Our objective was to evaluate the improvement in the performance of subject-level detection by readers when assisted by the automated statistical detection of change algorithm. MATERIALS AND METHODS: A total of 200 patients with MS with a mean interscan interval of 13.2 (SD, 2.4) months were included. Statistical detection of change was applied to the baseline and follow-up FLAIR images to detect potential new lesions for confirmation by readers (Reader + statistical detection of change method). This method was compared with readers operating in the clinical workflow (Reader method) for a subject-level detection of new lesions. RESULTS: Reader + statistical detection of change found 30 subjects (15.0%) with at least 1 new lesion, while Reader detected 16 subjects (8.0%). As a subject-level screening tool, statistical detection of change achieved a perfect sensitivity of 1.00 (95% CI, 0.88-1.00) and a moderate specificity of 0.67 (95% CI, 0.59-0.74). The agreement on a subject level was 0.91 (95% CI, 0.87-0.95) between Reader + statistical detection of change and Reader, and 0.72 (95% CI, 0.66-0.78) between Reader + statistical detection of change and statistical detection of change. CONCLUSIONS: The statistical detection of change algorithm can serve as a time-saving screening tool to assist human readers in verifying 3D FLAIR images of patients with MS with suspected new lesions. Our promising results warrant further evaluation of statistical detection of change in prospective multireader clinical studies.

Catalase-positive Eikenella corrodens and Eikenella-like isolates of human and canine origin.

Ten catalase-positive isolates and one catalase-negative isolate that had been assigned to Eikenella corrodens were compared to the nomenclatural type strain regarding selected phenotypic and molecular features and chromosomal deoxyribonucleic acid (DNA) relatedness using the spectrophotometric method. Five catalase-positive human isolates were assigned to the genomic species Eikenella corrodens on the basis of high DNA relatedness levels. Three others, among them strain Chen UB 204, exhibited only moderate degrees of DNA relatedness to the type strain and with each other. Two catalase-positive isolates from dogs were closely interrelated, but yielded only low degrees of DNA binding with Eikenella corrodens and the Eikenella-like human isolates. These findings confirm that the human eikenellas comprise more than one genomic species and that the canine strains represent a distinct taxonomic entity. The differentiation of the strains investigated by conventional phenotypic features, hydrolytic enzyme reactions, and cellular carbohydrate patterns was considered.

Occurrence of sialidase and N-acetylneuraminate lyase in Pasteurella species.

Pasteurella species and related taxa are opportunistic pathogens parasitizing on mucous membranes of higher organisms containing sialic acids. Therefore, sialidase is a virulence factor which up to now has been described to be present in P. haemolytica, P. multocida, and P. volantium. Because of some taxonomic changes and the description of many new species or still unnamed groups, the presence of sialidase and the metabolic successor enzyme, N-acetylneuraminate lyase, was investigated in 65 Pasteurella or Pasteurella-like strains. The detection of enzymes was performed by colorimetry, by paper chromatography and immunoelectrophoresis. Using bovine submaxillary mucin as substrate, sialidases were produced in all strains studied although the activities were different. Most strains but not all were positive in N-acetylneuraminate lyase, too. Taken together, the strains of Pasteurella sensu stricto showed the strongest activities of sialidase, those of the Pasteurella aerogenes complex the lowest. However, because of loss of sialidase activity during subcultivation, there is little feasibility to characterize Pasteurella species by these enzymes.

Granulocyte colony-stimulating factor prophylaxis before operation protects against lethal consequences of postoperative peritonitis.

BACKGROUND: Postoperative peritonitis has a high mortality in human beings. It is accepted that cytokines are important mediators in pathophysiology of sepsis. The recent failure of clinical trials increased the necessity to proof new drugs in more clinically relevant animal models. The aim of this study was to examine the effect of granulocyte colony-stimulating factor (G-CSF) in addition to an antibiotic in postoperative peritonitis. METHODS: Dose-response curves and experimental conditions were developed in a total of 295 rats. The main experiment included three groups: control animals receiving a fecal inoculum, a group treated with antibiotic, and a third group receiving G-CSF in addition to the antibiotic. The main outcome was death, but in addition, serum tumor necrosis factor (TNF) level was determined. RESULTS: The mortality rate of 60% in antibiotic treated animals was considerably reduced by G-CSF to 20%. All animals of the control group died during the observation period of 120 hours. A correlation between TNF levels and mortality rate was observed. In G-CSF treated animals total suppression of TNF serum levels was accessible in contrast to the others. CONCLUSIONS: In a clinically relevant animal model G-CSF was effective as an additional concept of prophylaxis. These data are promising toward clinical trials.

Rapid differentiation of avian Haemophilus-like strains by their whole-cell carbohydrate patterns.

The whole-cell carbohydrate patterns of 14 Haemophilus-like strains isolated from diseased birds were examined by capillary gas chromatography/mass spectrometry. The analysis of the peracetylated aldononitrile and O-methyloxime derivatives allowed the differentiation between the phenotypically and genetically different isolates. Starting from a pure culture the procedure needs only 5 hours for the preparation of the samples and 30 minutes for subsequent analysis and is of special value for rapid diagnosis.

Riemerella anatipestifer gen. nov., comb. nov., the causative agent of septicemia anserum exsudativa, and its phylogenetic affiliation within the Flavobacterium-Cytophaga rRNA homology group.

The phylogenetic position of the causative agent of septicemia anserum exsudativa, now most often referred to as [Moraxella] anatipestifer (brackets indicate a generically misnamed taxon) or "[Pasteurella] anatipestifer," was established by performing rRNA cistron similarity studies. [Moraxella] anatipestifer belongs to rRNA superfamily V, together with the genera Flavobacterium, Cytophaga, Flexibacter, Weeksella, Capnocytophaga, and Sphingobacterium. The detailed structure of rRNA superfamily V, which now contains five major rRNA homology groups, is described. An analysis of various phenotypic parameters, including new data (cellular proteins and fatty acids) and previously published data (respiratory quinones, enzyme activities, and classical phenotypic features), revealed that [Moraxella] anatipestifer differs in many aspects from its closest relatives, Flavobacterium indologenes, Flavobacterium gleum, Flavobacterium indoltheticum, Flavobacterium balustinum, Flavobacterium meningosepticum, and Weeksella zoohelcum. The combined genotypic and phenotypic data indicate that this organism should be placed in a separate genus; the name Riemerella anatipestifer gen. nov., comb. nov. is proposed for this bacterium. The specific epithet anatipestifer is kept in order to avoid nomenclatural confusion. However, it should be emphasized that the illness caused by this organism is a septicemic disease which is not restricted to ducks.

Characterization of the family Pasteurellaceae on the basis of cellular lipids and carbohydrates.

Selected strains representing established and newly described taxa in the family Pasteurellaceae were investigated for their cellular lipid and carbohydrate composition to clarify the taxonomic significance of such features. Methylated cellular fatty acids and acetylated derivatives of the cellular carbohydrates were determined by capillary gas chromatography using a flame ionization detector. In part the carbohydrates were identified by mass spectrometry. Phospholipids were determined by thin layer chromatography, the lipoquinones by high pressure liquid chromatography. The cellular fatty acid patterns proved to be uniform with minor variations, but the separation from the Neisseriaceae and from Moraxella was possible. Also the distribution of the phospholipids was uniform within the family. The lipoquinone contents were useful for the discrimination of groups within the family not necessarily reflecting the degree of genomic relatedness. The analysis of the cellular carbohydrates resulted in a common sugar pattern with all members of the family and characteristic carbohydrate profiles discriminating groups, often to the species level. All of the cytochemical features considered were useful for the characterization of the family Pasteurellaceae.

Occurrence of V-factor (NAD) independent strains of Haemophilus paragallinarum.

Strains of Bisgaard taxon 31, isolated from chickens in South Africa suffering from a respiratory disease with clinical symptoms and gross lesions similar to infectious coryza, showed great phenotypical similarities with Haemophilus paragallinarum infection except for NAD requirement, beta-galactosidase activity and maltose fermentation. Deoxyribonucleic acid-deoxyribonucleic acid hybridization confirmed a high level of genetic relatedness (DNA binding value, 89%) with Haemophilus paragallinarum. Guanine + cytosine content and genome size data also support the classification of taxon 31 strains within the species Haemophilus paragallinarum.

Characterization of Haemophilus paragallinarum by analysis of whole cell carbohydrates, fatty acids and phospholipids.

The whole cell carbohydrate composition of 20 strains of Haemophilus paragallinarum including strains representing all established serotypes and two NAD-independent strains, was determined by capillary gas-liquid chromatography. Selected strains of H. paragallinarum were analysed for their cellular fatty acids and phospholipids compositions. The gas chromatographic analysis in combination with the mass spectrometric identification of the carbohydrate derivatives revealed similar patterns with all strains investigated.

Rapid identification of Bordetella avium and related organisms on the basis of their cellular carbohydrate patterns.

Whole cell hydrolysates of Bordetella avium, B. bronchiseptica, B. pertussis, B. parapertussis, Alcaligenes faecalis, A. xylosoxidans ssp. denitrificans, A. xylosoxidans ssp. xylosoxidans, and A. piechaudii were analysed for their cellular carbohydrates by capillary gas-chromatography of per-acetylated aldononitriles and O-methyloximes, respectively. All Alcaligenaceae species could be discriminated on the basis of their carbohydrate profiles and a few conventional features. Taxometric evaluation of the established carbohydrate patterns confirmed previous separation of the taxa and the genetic relatedness within the Alcaligenaceae. One of the advantages of the method is, that the analysis is easy to perform and can be completed within less than 5 h, starting from a pure culture and, therefore, it seems to be applicable as a rapid method in routine diagnostics.

[The genetic classification of the Pasteurella pneumotropica complex]. / Untersuchungen zur genetischen Klassifikation des Pasteurella-pneumotropica-Komplexes.

Pasteurella pneumotropica with its biotypes Jawetz and Heyl are the most common bacterial pathogens associated with diseases in rodents. 23 P. pneumotropica biotype Jawetz, biotype Heyl and P. pneumotropica-like rodentia isolates have been investigated phenotypically by characterization of their micromorphology and biochemical fermentation reactions. The taxonomic position within the family Pasteurellaceae has been examined by DNA:DNA hybridisation (optical method). It could be shown that P. pneumotropica biotype Jawetz represents a genus-like cluster containing several species including the V-factor dependent Haemophilus Taxon B and the avian P. pneumotropica-like organism and therefore resembles a new species of the new genus. It is concluded that the biotype Heyl of P. pneumotropica taxonomically remains as a species within the family Pasteurellaceae, however without further relationship to other known genera or genus-like groups.

Some unusual members of the family Pasteurellaceae isolated from human sources--phenotypic features and genomic relationships.

Twelve human isolates exhibiting the properties of the family Pasteurellaceae but phenotypically deviating from established species, or resembling species of animal origin that are only rarely reported to occur in human materials, were checked for their identities by DNA-DNA hybridization. The collection consisted of one strain of Actinobacillus lignieresii, two strains of Actinobacillus hominis (mannose-positive), two hitherto undescribed Actinobacillus or Actinobacillus-like species, [Pasteurella] haemolytica biovar T, CDC group HB-5 (initially oxidase and indole-negative), a new species in the [Haemophilus] aphrophilus [Haemophilus] segnis group, a new sucrose-negative and gas-producing Pasteurella-like species, and three strains of Bisgaard's Pasteurella-like taxon 16. Some diagnostically useful features of these unusual human Pasteurellaceae are described.

Carbohydrate patterns, cellular lipoquinones, fatty acids and phospholipids of the genus Pasteurella sensu stricto.

The carbohydrate patterns, isoprenoid quinones, fatty acids and phospholipids of the species of the genus Pasteurella sensu stricto were investigated to evaluate their taxonomic significance and their applicability for the identification of these bacteria. Forty-six representative strains of the 11 species of Pasteurella were examined. The data obtained indicated that the carbohydrate patters are species or subspecies specific and may, therefore, become an important and useful diagnostic tool. Fatty acids and phospholipids showed a feature characteristic of the members of the genus and the isoprenoid quinones exhibited a mostly genus-specific feature with remarkable quantitative differences.

Inter- and intrafamilial similarities of rRNA cistrons of the Pasteurellaceae.

We performed hybridizations between labeled rRNAs from seven representative members of the family Pasteurellaceae and from three other taxa on the one hand and DNAs from 53 strains known or presumed to belong to the Pasteurellaceae on the other hand. The members of the Pasteurellaceae are most closely related to members of the Enterobacteriaceae, the Vibrionaceae, the Aeromonadaceae, and the genus Alteromonas. The family Pasteurellaceae is very heterogeneous. There are at least seven rRNA branches. Several organisms with the same genus name are dispersed over the entire dendrogram. The "Histophilus ovis," [Haemophilus] ducreyi, [Actinobacillus] actinomycetemcomitans, and [Haemophilus] aphrophilus rRNA branches are separate and quite remote from the three authentic genera in this family; this might justify eventual later separate generic status. DNA-rRNA hybridization with suitable, labeled rRNA probes is an excellent method to establish whether an organism belongs in the Pasteurellaceae; e.g., some strains of Bisgaard's taxa 7, 13, and 16 and of the gas-producing "SP" group certainly belong in this family, whereas three bovine lymphangitis organisms (strains NCTC 10547, NCTC 10549, and NCTC 10553), [Haemophilus] piscium ATCC 10801T (T = type strain), and [Pasteurella] piscicida ATCC 17911 belong in the Enterobacteriaceae, the Aeromonadaceae, and the Vibrionaceae, respectively.

Deoxyribonucleic acid relatedness and phenotypic variation among human isolates of Eikenella corrodens.

The type strain of Eikenella corrodens (Eiken 1958) Jackson and Goodman 1972 and eleven epidemiologically independent clinical isolates recovered from periodontal locations, putrid wounds, abscesses, and bacteraemias were investigated for their genomic relationships by DNA-DNA hybridization with the renaturation method, genome molecular complexity, DNA base composition and some phenotypic features. The bacterial strains studied were interrelated at or above the 80% DNA binding level, their chromosomal DNAs exhibiting a mean molecular mass of 1.7 x 10(9) daltons and a mean guanine plus cytosine content of 55.1 mol%. Variations in colonial morphology, hemolytic activity on sheep blood agar, reduction of nitrates, oxidation of carbohydrates, lipase, leucine, valine, and cystine aminopeptidase and acid phosphatase activities occurred among closely interrelated strains. The definition of the species and current identification keys must be emended accordingly.

Genomic relationships and species differentiation in the genus Capnocytophaga.

Ten epidemiologically independent Capnocytophaga strains from clinical materials constituted three distinct DNA homology groups corresponding to the established species, Capnocytophaga ochracea, sputigena, and gingivalis. The three groups exhibited only low, or even insignificant degrees of genomic relatedness mutually, and to a reference culture of CDC group DF-2. All of five Capnocytophaga ochracea strains considered were involved in topic infections whereas four strains, isolated from blood belonged to either Capnocytophaga sputigena or Capnocytophaga gingivalis. However, Capnocytophaga ochracea and Capnocytophaga sputigena could not be discriminated on the basis of DNA base composition, genome size, or phenotypic features including cellular fatty acids, lipoquinones, and various fermentation and hydrolase reactions. The need for additional phenotypic criteria characterizing species of Capnocytophaga is underlined by the present findings.

Phenotypic and genetic relationships of so-called Moraxella (Pasteurella) anatipestifer to the Flavobacterium/Cytophaga group.

So-called Moraxella (or Pasteurella) anatipestifer and members of the Flavobacterium/Cytophaga group exhibit remarkable common features: lack of flagellation, low guanine + cytosine content of the chromosomal DNA, production of menaquinones and branched-chain fatty acids, absence of carbohydrate fermentation, and similar patterns of hydrolytic enzymes. Using the renaturation method of DNA:DNA hybridization two urease-negative European isolates and the urease-positive type strain (which was isolated in the United States) of M. P. anatipestifer were shown to have about 85% of their genome DNA base sequences in common; they may represent two subspecies. The type strain of this species was neither measurably related to the type species of the genus Moraxella nor to selected members of the family Pasteurellaceae (Pohl 1981). On the other hand, low but significant degrees of DNA binding between selected strains of so-called M. anatipestifer, Cytophaga marinoflava, Flavobacterium meningosepticum, F. odoratum and F. pectinovorum were observed. On the basis of these findings the transfer of the so-called M. anatipestifer to the Flavobacterium/Cytophaga group (family Cytophagaceae) is proposed. More detailed investigations are required to establish its relationship at the genus level.

Characterization and identification of bovine and ovine Pasteurellaceae isolated from the oral cavity and rumen of apparently normal cattle and sheep.

Reinvestigations of 121 strains previously described as Actinobacillus lignieresii showed that only fifteen strains (12%) had phenotypic characters compatible with A. lignieresii sensu stricto. Four strains were diagnosed as Pasteurella multocida and nine strains as P. haemolytica biogroup 1. The remaining organisms had phenotypic characters compatible with Pasteurellaceae, but could not be classified with accepted species. Fifty-one of the strains investigated had phenotypic characters allowing classification with P. haemolytica biogroups 6 through 9. In addition 19 strains made up at least two new biogroups within the bovine and ovine P. haemolytica complex. Twenty-seven unclassified ovine isolates formed a heterogeneous group provisionally designated taxon 18. At least four biovars were demonstrated within taxon 18. The taxonomic significance of characters separating the P. haemolytica complex and taxon 18 as well as characters separating biogroups within these groups remains to be investigated genetically. The necessity of extended phenotypic characterization within the family Pasteurellaceae Pohl 1981 is underlined by the present findings.

Taxonomy of some recently described avian Pasteurella/Actinobacillus-like organisms as indicated by deoxyribonucleic acid relatedness.

Members of the family Pasteurellaceae Pohl 1981 are frequently encountered in birds as parasites or pathogens, e.g. the well-known species Pasteurella multocida, Pasteurella gallinarum, Haemophilus paragallinarum, and three species containing strains that had been previously classified as "Haemophilus avium"(Pasteurella avium, Pasteurella volantium, and an unnamed Pasteurella species defined by Mutters et al., 1985). A variety of additional taxa which had been tentatively assigned to the family do not belong to recognised species and could not even be classified to the genus level. In the present investigation selected Pasteurella/Actinobacillus-like isolates from fowl and zoo birds were examined for their genetic relationships with established species of Pasteurellaceae, using the renaturation method of deoxyribonucleic acid (DNA):DNA hybridisation. Guanine plus cytosine contents and genome masses were also considered. On the basis of DNA relatedness (1) the genus Pasteurella sensu stricto was extended to include Bisgaard's taxa 1 and 4 as two new Pasteurella species. (2) Bisgaard's taxa 2 and 3 and some phenotypically similar organisms isolated from zoo birds were shown to form a large distinct group which seems to represent a new genus with several species within the family Pasteurellaceae. (3) Another large heterogeneous, genus-like group consisted of strains labelled "Actinobacillus salpingitidis" and the phenotypically similar "Avian Pasteurella haemolytica-like" organisms; this group was placed in the close vicinity of the genus Actinobacillus. (4) Finally, a group of isolates labelled "Avian haemolytic Actinobacillus-like" organisms appeared to be heterogeneous on the species level but could be included in the genus Actinobacillus on the basis of DNA binding data. By co-evaluation of genetic relatedness and phenotypic features of avian Pasteurella/Actinobacillus-like isolates some diagnostically useful criteria have been detected.