Classification of organisms previously reported as the SP and Stewart-Letscher groups, with descriptions of Necropsobacter gen. nov. and of Necropsobacter rosorum sp. nov. for organisms of the SP group.

To allow classification of bacteria previously reported as the SP group and the Stewart-Letscher group, 35 isolates from rodents (21), rabbits (eight), a dog and humans (five) were phenotypically and genotypically characterized. Comparison of partial rpoB sequences showed that 34 of the isolates were closely related, demonstrating at least 97.4 % similarity. 16S rRNA gene sequence comparison of 20 selected isolates confirmed the monophyly of the SP group and revealed 98.5 %-100 % similarity between isolates. A blast search using the 16S rRNA gene sequences showed that the highest similarity outside the SP group was 95.5 % to an unclassified rat isolate. The single strain, P625, representing the Stewart-Letscher group showed the highest 16S rRNA gene similarity (94.9-95.5 %) to members of the SP group. recN gene sequence analysis of 11 representative strains resulted in similarities of 97-100 % among the SP group strains, which showed 80 % sequence similarity to the Stewart-Letscher group strain. Sequence similarity values based on the recN gene, indicative for whole genome similarity, showed the SP group being clearly separated from established genera, whereas the Stewart-Letscher group strain was associated with the SP group. A new genus, Necropsobacter gen. nov., with only one species, Necropsobacter rosorum sp. nov., is proposed to include all members of the SP group. The new genus can be separated from existing genera of the family Pasteurellaceae by at least three phenotypic characters. The most characteristic properties of the new genus are that haemolysis is not observed on bovine blood agar, positive reactions are observed in the porphyrin test, acid is produced from (+)-L-arabinose, (+)-D-xylose, dulcitol, (+)-D-galactose, (+)-D-mannose, maltose and melibiose, and negative reactions are observed for symbiotic growth, urease, ornithine decarboxylase and indole. Previous publications have documented that both ubiquinones and demethylmenaquinone were produced by the proposed type strain of the new genus, Michel A/76(T), and that the major polyamine of representative strains (type strain not included) of the genus is 1,3-diaminopropane, spermidine is present in moderate amounts and putrescine and spermine are detectable only in minor amounts. The major fatty acids of strain Michel A/76(T) are C(14 : 0), C(16 : 0), C(16:1)ω7c and summed feature C(14 : 0) 3-OH/iso-C(16 : 1) I. This fatty acid profile is typical for members of the family Pasteurellaceae. The G+C content of DNA of strain Michel A/76(T) was estimated to be 52.5 mol% in a previous investigation. The type strain is P709(T) ( = Michel A/76(T)  = CCUG 28028(T)  = CIP 110147(T)  = CCM 7802(T)).

Is characterization of a single isolate sufficient for valid publication of a new genus or species? Proposal to modify recommendation 30b of the Bacteriological Code (1990 Revision).

From 1990 to 2000, the number of published named taxa based upon new isolates at species and genus levels in International Journal of Systematic and Evolutionary Microbiology, formerly International Journal of Systematic Bacteriology, have increased by approximately four- and sevenfold, respectively. New taxa based upon characterization of only a single isolate remained at around 40% for both categories. The Bacteriological Code (1990 Revision) has no recommendations on the number of strains required for definition of new taxa. For a few groups, a minimum number of 5-10 strains has been suggested in minimal standards. Since an exponential increase in new taxa can be expected in the future, the authors discuss problems related to naming new species and genera based upon descriptions of a single isolate and suggest that this practice is re-evaluated. It is proposed that the following should be added to Recommendation 30b of the Bacteriological Code: 'Descriptions should be based on as many strains as possible (minimum five), representing different sources with respect to geography and ecology in order to be well characterized both phenotypically and genotypically, to establish the centre (from which the type strain could be chosen) and the extent of the cluster to be named. In addition, comparative studies should be performed, including reference strains that represent neighbouring species and/or genera, in order to give descriptions that are sufficiently detailed to allow differentiation from these neighbours.'

Proposed new bacterial taxa and proposed changes of bacterial names published during 1997 and considered to be of interest to medical or veterinary bacteriology.

A list of names of bacteria published or validated in 1997 is presented. Comments are made of the tendency to base names of new taxa on a single bacterial strain and the consequences for reliable descriptions that this tendency implies.

The 1998 list. Proposed new bacterial taxa and proposed changes of bacterial names published during 1998 and considered to be of interest to medical or veterinary bacteriology (an informational note).

A list of names published or validated in 1998 is presented.

The 1997 list. Proposed new bacterial taxa and proposed changes of bacterial names published during 1997 and considered to be of interest to medical or veterinary bacteriology. An informational note.

A list of names published or validated in 1997 is presented. We also comment on the tendency to base names of new taxa on a single bacterial strain, and the consequences for reliable descriptions that this tendency implies.

Problems of identification in clinical microbiology exemplified by pig bite wound infections.

Our experience from attempts to identify bacteria isolated from boar bite/gore wounds is the background for a discussion of identification problems. Some organisms, although not very common or well-known, can be identified when using commercial kits or conventional methods, provided they are sufficiently characterized, as exemplified by Pasteurella aerogenes isolated from cases 1 and 2. Some organisms may be wrongly identified, or not identified, by both commercial kits and conventional methods, unless seen by experienced microbiologists with knowledge of the original literature. This is exemplified by case 3, in which the final identification result was Bisgaard's taxon 15. Sometimes isolates cannot be identified even in reference laboratories and by using available identification tables and databases. In such cases, the organism involved may turn out to belong to a previously undescribed taxon. This is illustrated by the strains isolated from cases 4 and 5.

The 1997 list. Proposed new bacterial taxa and proposed changes of bacterial names published during 1997 and considered to be of interest to medical or veterinary bacteriology. An informational note.

A list of names published or validated in 1997 is presented. We also comment on the tendency to base names of new taxa on a single bacterial strain, and the consequences for reliable descriptions that this tendency implies.

The 1997 list. Proposed new bacterial taxa and proposed changes of bacterial names published during 1997 and considered to be of interest to medical or veterinary bacteriology (an informational note).

A list of names published or validated in 1997 is presented. We also comment on the tendency to base names of new taxa on a single bacterial strain, and the consequences for reliable descriptions that this tendency implies.

Capnocytophaga canimorsus septicemia in Denmark, 1982-1995: review of 39 cases.

Thirty-nine Danish cases of Capnocytophaga canimorsus septicemia were reviewed to determine the clinical course of this infection. The cases of septicemia were related to recent dog bites or other close contact with dogs. The period from the bite to the onset of symptoms ranged from 1 to 8 days. The mean age of the patients was 59.1 years (range, 28-83 years). Underlying conditions included previous splenectomy and alcoholism. Thirteen patients had previously been in good health. Common initial symptoms were fever, malaise, myalgia, vomiting, diarrhea, abdominal pain, dyspnea, confusion, headache and skin manifestations. Disseminated intravascular coagulation developed in 14 patients, meningitis in 5, and endocarditis in 1. Twelve of the patients died. All patients except two were treated with penicillin or ampicillin. Five patients had received antibiotics prior to admission. Attention should be drawn to C. canimorsus septicemia in cases of febrile illness following dog bites or contact with dogs, as well as those involving previously healthy persons. The incidence of this condition in Denmark is estimated to be 0.5 case per 1 million people per year.

Pasteurella aerogenes isolated from ulcers or wounds in humans with occupational exposure to pigs: a report of 7 Danish cases.

Pasteurella aerogenes is rarely isolated from human specimens. The species is found in the digestive tract of pigs. From 1976 to 1994 7 strains were cultured in Denmark from wounds or ulcers. Five patients were bitten by pigs and 2 patients with ulcers were employed in pig farming. A mixture of bacterial species was often found. All 7 strains of P. aerogenes were susceptible to ampicillin, cephalosporins and ciprofloxacin. Ability to hydrolyse urea, to produce oxidase and catalase, to decarboxylate ornithine and to produce gas from glucose and inability to produce indole was characteristic for P. aerogenes. Most bite wounds were located on the lower lateral part of the thigh. Foul smelling pus and abscess formation was the rule. Incision, drainage and antibiotic treatment were usually necessary.