R. F. Jones

Isolation and characterisation of bacteria from pyothorax (empyaemia) in cats

Abstract Samples from 19 cases of feline empyaemia were examined. All cases had no prior treatment and specimens were collected by thoracocentesis after preparation of the skin as for aseptic surgery. Of the 87 bacterial strains isolated, 70 (80.5%) were anaerobes and 17 (19.5%) were facultative anaerobes. Fourteen cases contained mixtures of anaerobes and facultative anaerobes, and five contained anaerobes only. Bacteroides was the most commonly isolated genus (42.5% of all isolates). Clostridium villosum (16.1%) was the most frequently isolated bacterial species followed by Peptostreptococcus anaerobius and Pasteurella multocida (each 12.6%). The most commonly isolated anaerobic species was Clostridium villosum sp.nov. (20% of anaerobic isolates and 16.1% of all isolates) and Pasteurella multocida was the most commonly isolated facultatively anaerobic species (64.7% of facultative isolates and 12.6% of all isolates).

Isolation and characterisation of bacteria from abscesses in the subcutis of cats.

Thirty-six closed abcesses in the subcutis of cats were examined. Of 168 bacterial strains isolated, 121(72%) were anaerobes and 47 (28%) were facultative anaerobes. Twenty-six abscesses contained mixtures of facultative anaerobes and anaerobes, six contained anaerobes only and four contained facultative anaerobes only. Bacteriodes was the genus most commonly isolated (28.6% of all isolates) followed by Fusobacterium (19.0%) and Pasteurella (multocida) (13.1%). Peptostreptococcus anaerobius was the most commonly isolated anaerobic species (13.2% of anaerobic isolates and 9.5% of all isolates)and Past, multocida was the most commonly isolated facultative anaerobe (46.8%; 13.1%of all isolates).

Bacteroides salivosus sp. nov., an asaccharolytic, black-pigmented species from cats

A new species, Bacteroides salivosus sp. nov., is proposed for black-pigmented, asaccharolytic Bacteroides strains from cats, isolated from subcutaneous abscesses and empyemas, as well as from gingival margins of normal mouths. The bacterium is an obligately anaerobic, gram-negative, brown- or black-pigmented, asaccharolytic, nonmotile, nonsporeforming rod that does not grow in 20% bile and has a guanine-plus-cytosine content of 42 to 44 mol%. It has 12% deoxyribonucleic acid homology with the human type strain of Bacteroides gingivalis (ATCC 33277T) and 1% deoxyribonucleic acid homology with the human type strain of Bacteroides asaccharolyticus (ATCC 25260T). Strain VPB 157 (NCTC 11632T) is the type strain. Unlike B. gingivalis, B. salivosus produces catalase, and the colonies of the type strain fluoresce at 24 and 48 h, although some other strains do not fluoresce. It does not agglutinate sheep erythrocytes. Unlike either B. asaccharolyticus or Bacteroides endodontalis, it has trypsinlike activity and produces large quantities of phenylacetic acid.

Deoxyribonucleic Acid Hybridization among Strains of Fusobacteria Isolated from Soft Tissue Infections of Cats: Comparison with Human and Animal Type Strains from Oral and Other Sites

Fifty-two strains of Fusobacterium species were isolated from oral cavities or lesions contaminated with feline oral flora from 49 different cats. Forty-five strains were from purulent lesions, while the remaining seven strains came from the normal gingivae of three cats less than 6 months old. Of 36 strains which were phenotypically like Fusobacterium russii, 29 showed an average level of deoxyribonucleic acid (DNA) homology of 87% with the type strain of F. russii, strain ATCC 25533 (isolated from a cat). The remaining seven strains showed an average level of DNA relatedness to F. russii of 53%. An additional eight strains, which were identified as Fusobacterium necrophorum by biochemical tests, had polyacrylantide gel electrophoresis patterns unlike those of F. necrophorum and an average level of DNA homology with F. necrophorum ATCC 25286T(T = type strain) of 25%. These strains showed an average level of DNA homology with Fusobacterium alocis ATCC 35896Tof 96%, although the results of polyacrylamide gel electrophoresis and biochemical tests obtained with the isolated strains were unlike the results obtained with F. alocis ATCC 35896T. Four strains isolated from cats had biochemical characteristics of Fusobacterium nucleatum ATCC 25586T. The average level of intragroup DNA homology of these strains with F. nucleatum ATCC 25586Twas 66%, although their polyacrylamide gel electrophoresis patterns differed somewhat from those of the type strain. Four strains isolated from cats were identified as Fusobacterium naviforme on the basis of phenotypic tests; they had an average level of homology with the type strain of F. naviforme, strain ATCC 25832, of 17% and showed low degrees of relatedness with DNAs from all other type strains tested.

Asaccharolytic Black-Pigmented Bacteroides Strains from Soft- Tissue Infections in Cats

Using phenotypic characterization, we found that 17 strains of asaccharolytic pigmented Bacteroides species isolated from soft-tissue infections in cats could be divided into five distinct groups. All of these strains were catalase positive, required vitamin K-hemin for growth, did not grow in bile, and did not exhibit α-glucosidase activity. The organisms in groups A and E (five strains) did not fluoresce under ultraviolet light at 365 nm and were indole positive. Group A organisms hemagglutinated sheep erythrocytes, but group E strains did not. The members of both of these groups produced large amounts of phenylacetic acid (group A average, 497 μg/ml; group E average, 404 μ/ml), and both groups showed trypsin-like activity (detected by using N-benzoyl-dl-arginine-2-napthylamide). The guanine-plus-cytosine contents of the deoxyribonucleic acids of group A strains ranged from 48 to 51 mol%; group E strain guanine-plus-cytosine contents ranged from 44 to 47 mol%. The members of groups B, C, and D (12 strains) all fluoresced and were indole positive. Group D strains hemagglutinated sheep erythrocytes, whereas groups B and C strains did not. Trypsin-like activity occurred in groups C and D but not in group B, and all strains produced phenylacetic acid (group B average, 11 μg/ml; group C average, 313 μg/ml; group D average, 999 μg/ml). The group B, C, and D, deoxyribonucleic acids had the following guanine-plus-cytosine contents: group B, 45 to 47 mol%; group C, 45 to 48 mol%; group D, 49 to 50 mol%. All groups of strains differed phenotypically and by isoelectric focusing of bacterial proteins from the asaccharolytic pigmented type strains Bacteroides gingivalis ATCC 33277 and Bacteroides asaccharolyticus ATCC 25260; they were different also from the saccharolytic pigmented type strains Bacteroides levii ATCC 29147, Bacteroides intermedius ATCC 25611, and Bacteroides macacae ATCC 33141.

Bacteroides tectum sp. nov. and Characteristics of Other Nonpigmented Bacteroides Isolates from Soft-Tissue Infections from Cats and Dogs

Sixty strains of obligately anaerobic gram-negative nonsporeforming nonpigmented Bacteroides species were isolated from subcutaneous abscesses and pyothoraxes of cats and dogs. All of these strains grew well in bile and produced acetic, propionic, and succinic acids as major products of fatty acid metabolism. Phenotypic and deoxyribonucleic acid (DNA) homology data divided the strains into five groups. Only three strains were members of Bacteroides fragilis, as determined by biochemical and DNA homology analyses. All of the other strains showed negligible levels of DNA homology with human strains of B. fragilis, Bacteroides distasonis, Bacteroides vulgatus, Bacteroides thetaiotaomicron, and Bacteroides ovatus, although they did have substantial ribosomal ribonucleic acid homology with these species. One group comprising 52 strains is proposed as a new species, Bacteroides tectum, having three distinct homology clusters. Strains of B. tectum are obligately anaerobic, gram-negative, nonmotile, nonpigmented, nonsporeforming rods that grow well in bile, do not produce indole, and only weakly ferment carbohydrates. They have a DNA guanine-plus-cytosine ratio of 46 mol% but do not exhibit DNA homology with phenotypically similar human strains of Bacteroides.

Clostridium villosum sp. nov. from Subcutaneous Abscesses in Cats

Clostridium villosum sp. nov., isolated from subcutaneous abscesses of cats, is an obligately anaerobic, rod-shaped, sporeforming, monmotile organism which is gram positive in its early stages of growth and gram negative after 18 to 24 h. All strains of this species produce acetic, isobutyric, butyric, isovaleric, lactic, methylmalonic, and succinic acids from cooked meat-carbohydrate and peptone-yeast extract cultures supplemented with 5% horse serum. All of the strains produce ammonia and liquefy gelatin weakly but do not ferment acids or react in any other biochemical tests performed. The pattern of volatile acids produced, the lack of biochemical activity, the colonial morphology, and the late spore production distinguish C. villosum from other Clostridium species so far described. The type strain of C. villosum is VSB 3349; a culture of this strain has been deposited in the National Collection of Type Cultures under the number 11220.

Description of Strains of Peptostreptococcus anaerobius Isolated from Subcutaneous Abscesses in Cats

Strains of Peptostreptococcus, Streptococcus and of a Gram-positive coccus, which was initially isolated as an anaerobe but grew subsequently as a facultative organism, were isolated from subcutaneous abscesses in cats. The cat strains of Peptostreptococcus gave metabolic fermentation products in combinations described for P. anaerobius. The Streptococcus strains conformed to the group S. intermedius. The facultative organism described had the metabolic products of P. anaerobius but the distinctly different biochemical characteristics of S. intermedius and fits neither of the genera strictly.