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.

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.

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.

Lack of evidence for the occurrence of Pasteurella ureae in rodents.

The taxonomy of five typical human isolates of Pasteurella ureae, one strain of Actinobacillus hominis, and three murine isolates which had been designated as Pasteurella ureae in published reports were re-examined. Their taxonomic relationships were investigated by both conventional phenotypic characterization and by DNA/DNA hybridization using the renaturation method. The human Pasteurella urea strains were highly homogeneous in their phenotypes and in their DNA reassociation. The strain of Actinobacillus hominis studied was genetically distinct from Pasteurella ureae, but was located, like Pasteurella ureae, in the Actinobacillus group. The remaining strains exhibited only low DNA relatedness with Pasteurella ureae and each other; this agreed with their phenotypic divergence. Two of the murine isolates were identified as indole-negative variant strains of Pasteurella pneumotropica sensu stricto (i.e., type Jawetz), or of the type Heyl of Pasteurella pneumotropica, respectively. The remaining murine isolate appears to represent a hitherto unrecognized species of Pasteurellaceae. So far, there is no evidence for the occurrence of Pasteurella ureae outside the human host.

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.

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.

Genetic and phenotypic comparison of three new avian Haemophilus-like taxa and of Haemophilus paragallinarum Biberstein and White 1969 with other members of the family Pasteurellaceae Pohl 1981.

In the course of post-mortem bacteriological examinations, several previously unreported bacterial strains were isolated from budgerigars, pigeons, kestrels, and a goose. They have been separated into three distinct collectives according to their cultural, morphological, and biochemical characteristics. Since they require V factors, they were tentatively assigned to the genus Haemophilus Winslow et al. 1917. This preliminary classification was checked by determination of guanine + cytosine contents and genome sizes and by DNA:DNA hybridization tests among reference strains of the three new avian taxa and recognized species of the family Pasteurellaceae Pohl 1981. With the same methods, the genetic relationships of Haemophilus paragallinarum Biberstein and White 1969 within the family were determined. It could be shown that the three avian Haemophilus-like taxa have to be regarded as new species within the family Pasteurellaceae not affiliated with the recognized genera Actinobacillus, Haemophilus and Pasteurella. H. paragallinarum must be excluded from the genus Haemophilus because of its closer relationship to the actinobacilli. All strains investigated can be differentiated from each other and from recognized species of Pasteurellaceae using an appropriate set of biochemical tests.

[On the phenotypical characteristics of human pasteurella, and pasteurella-like isolates (author's transl)]. / Zur phänotypischen Charakteristik humaner Pasteurella-und pasteurella-ähnlicher Stämme.

Fourty-two human isolates that had been designated Pasteurella, or pasteurella-like organisms in the bacteriological routine laboratory were phenotypically characterized considering conventional, morphological and physiological features, and respiratory quinones. Thirty-seven of these strains fitted into the large traditional species, P. multocida, the majority of them being associated with alterations of the respiratory tract, and the rest with intestinal diseases, or putrid wound secretions mostly following animal bite or scratch lesions. Two strains isolated from sputum, or sinus maxillaris punctate, respectively, were P. ureae, and one strain recovered from a septicemic blood samle proved to be Cardiobacterium hominis. A pasteurella-like strain isolated from putrid sputum and an unusual organism that had been isolated from the cerebrospinal fluid of an infant with putrid meningitis remained unidentified. The bacteriological data are discussed with respect to the diagnostics of Pasteurella and similar organisms and especially, the range of phenotypical variation within the species, P. multocida.

Deoxyribonucleic acid relatedness of some menaquinone-producing Flavobacterium and Cytophaga strains.

Nine menaquinone-forming strains of the Flavobacterium--Cytophaga complex with DNA base compositions between 35 and 45 moles percent guanine-plus-cytosine were investigated for genome sizes and DNA relatedness by DNA:DNA hybridization in vitro, using the optically recorded initial reassociation kinetics. Two strains representing C. hutchinsonii and C. marinoflava proved to be related on the 50 percent binding level, i.e. on a level of DNA relatedness commonly found within well-classified conventional genera of bacteria. Strains of C. johnsonae, F. heparinum, F. meningosepticum, F. odoratum, F. pectinovorum, and an unnamed Flavobacterium--Cytophaga strain were found to be interrelated, and linked to the genus Cytophaga, on the 30, or 20 percent binding levels, respectively. These findings indicate that the organisms in question are related to Cytophaga. They therefore should be transferred into the family Cytophagaceae.

[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.

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.

[On the taxonomy of Actinobacillus, Haemophilus, and Pasteurella: DNA base composition, respiratory quinones, and biochemical reactions of representative collection cultures (author's transl)]. / Zur Systematik von Actinobacillus, Haemophilus and Pasteurella: Basenzusammensetzung der DNS, Atmungschinone und kulturell-biochemische Eigenschaften repräsentativer Sammlungsstämme.

In a comparative study, 63 collection cultures representing 38 nomenspecies of, or assigned to, the genera Actinobacillus, Haemophilus, or Pasteurella were characterized by phenotypical features and deoxyribonucleic acid base composition. The latter was calculated from the thermal denaturation point. Biochemical reactions were tested in differential media commonly used for Enterobacteriaceae, and two test procedures were compared: (i) pure cultures with haematin and nicotine adenine dinucleotide added, where necessary, and (ii) xenocultures with an asaccharolytic Acinetobacter strain (ST 661/60). Furthermore, the respiratory quinones, and the effect of fumarate on oxygen-limited growth were considered. On the basis of these and some additional physiological and morphological criteria, a definition of the Actinobacillus-Haemophilus-Pasteurella group as a whole was established which appears to rank as a family. Several misclassified species, i.e. the so-called Actinobacillus actinoides, Haemophilus piscium, Haemophilus vaginalis, Pasteurella anatipestifer, and the organisms of the Bovine Lymphangitis group were eliminated, and the position of so-called Pasteurella piscicida was questioned. Some principles of subdivision of the group, and some of the practical identification procedures were discussed.

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.

Lipoquinones of some spore-forming rods, lactic-acid bacteria and actinomycetes.

The respiratory quinones of 73 strains of Gram-positive bacteria including spore-forming rods, lactic-acid bacteria and actinomyctes were examined. Menaquinones with seven isoprenoid units (MK-7) were the main quinone type found in representatives of the genus Bacillus and in Sporolactobacillus inulinus. However, a strain of B. thuringiensis produced MK-8 in addition to MK-7, and strains of B. lentus and B. pantothenticus appeared to produce MK-9 and MK-8, respectively, with no MK-7. In the clostridia and lactic-acid bacteria, no quinones were found, except in Pediococcus cerevisiae NCTC 8066 and Lactobacillus casei subsp. rhamnosus ATCC 7469, which contained menaquinones, and Streptococcus faecalis NCTC 775 and HIM 478-1, which contained demethylmenaquinones, in relatively low concentrations. Menaquinones were also found in the actinomycetes (except Actinomyces odontolyticus and Bifidobacterium bifidum which did not produce any quinones) and in Protaminobacter alboflavus ATCC 8458, the so-called Actinobacillus actinoides ATCC 15900 and Noguchia granulosis NCTC 10559.

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.

[Wild-type and acquired resistance patterns of clinical isolates of Escherichia coli (author's transl)]. / Wildtypische und erworbene Resistenzmuster klinischer Isolate von Escherichia coli.

Stored data on the inhibition zone diameters of 2274 strains of Escherichia coli that had been determined during the first five investigation periods (1975 to 1977) of the Arbeitsgemeinschaft "Resistenz" using the standard disc susceptibility test on Mueller-Hinton agar, were evaluated for: (1) frequency of secondary resistance to ampicillin, carbenicillin, cephalothin, chloramphenicol, kanamycin, nitrofurantoin, streptomycin, sulfamethoxazole, tetracycline, and trimethoprim-sulfamethoxazole on the basis of statistically defined break points; (2) number, frequency, and qualitative characteristics of multiple resistance patterns; (3) regional distribution of the more common resistance patterns; (4) more detailed characterization of resistance patterns using the mean diameters of inhibition zones; and (5) occurrence of additional resistance determinants. The significance of such data in the epidemiological control of resistance to chemotherapeutics in gram-negative bacteria is discussed.

Lipoquinones of some bacteria and mycoplasmas, with considerations on their functional significance.

In a comparative study the lipoquinones of some chemoorganotrophic, facultatively aerobic bacteria, and representative Acholeplasma, Mycoplasma, Spiroplasma, and Thermoplasma strains were investigated. The quinones were partly purified by preparative thin layer chromatography of lipid extracts, and characterized by their difference spectra (reduced minus oxidized) and Rf values. Respiring bacteria expectedly contained benzoquinones and/or naphthoquinones in micromolar concentrations whereas some aerotolerant, cytochrome-less, gram-positive bacteria were found to contain menaquinones in nanomolar concentrations, or even no quinones; only Streptococcus faecalis, an organism supposed to use a rudimentary, flavin-terminated respiratory chain system produced desmethyl menaquinone in amounts ranging between "high" and "low" quinone contents. Among the mycoplasmas investigated, only Thermoplasma acidophilum was found to be capable of synthesizing quinones (MK-7) in the micromolar order of magnitude indicating a respiratory electron transport system. The presence of energetically useful respiratory chain systems in Acholeplasma, Mycoplasma, and Spiroplasma is questioned since these organisms contain quinones (MK-4) in nanomolar concentrations, or no quinones, depending on the presence of exogeneous MK-6 in the growth medium. The possible metabolite role of menaquinones present in "low" amounts, as well as the role of NADH oxidase systems more or less tightly bound to the cytoplasmic membrane with the mycoplasmas deserves further investigation.

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.

Phenotypic differentiation of Pasteurella sensu stricto and the Actinobacillus group.

The current classification of recognized actinobacilli and pasteurellas does not allow differentiation of the two genera by their phenotypic features. Recent investigations of their genetic relationships have shown that several species hitherto assigned to the genus Pasteurella are more closely related to the actinobacilli. Moreover, some recently described taxa were located by DNA-DNA hybridization in one or the other of the two genera. On the basis of the genetic system, improved identification keys have been devised which separate the taxonomic groups on the genus and species levels according to an appropriate set of biochemical characteristics.

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.