Characterization of “Pasteurella” piscicida Isolated from White Perch and Cultivated Yellowtail

The morphological, physiological, and biochemical characteristics of twelve “Pasteurella” piscicida strains isolated from white perch and yellowtail are described and the present uncertain taxonomic status of the organisms is discussed. The organisms isolated were gram-negative rods showing bipolar staining and pleomorphism. No spores or flagella were observed. They were non motile and viscid colonies were formed. Growth was observed in a temperature range of 20 to 30 C and the salinity range of growth was between 0.5% and 4.0%. They were aerobic and facultative anaerobic. Oxidase and catalase were produced. Nitrates were not reduced to nitrites. Lysine and ornithine decarboxylases were not produced but arginine dihydrolase was produced. The egg yolk reaction was positive. Tween 80 and tributyrin were decomposed. Phosphatase was produced. Beta hemolysis was revealed on a medium containing defibrinated blood from chickens or carp but not from mammals. Methyl red and Voges–Proskauer tests were positive, and acetoin was produced from 2, 3-butanediol. Glucose was fermented without gas production. Acid was produced from fructose, mannose, galactose, sucrose, maltose, dextrin and glycerol. These organisms differed from all other members of the genus Pasteurella with respect to nitrate reduction, arginine dihydrolase, Voges–Proskauer and methyl red tests. The formation of viscid colonies and inability to grow in a medium without sodium chloride or at 37 C were additional characteristics of these organisms.     

西伯利亚鲟(Acipenser baerii)致病性维氏气单胞菌的分离鉴定

摘要：【目的】本研究旨在寻找引起养殖西伯利亚鲟鱼(Acipenser baerii)病害的致病因子。【方法】从北京地区自然患病的西伯利亚鲟鱼体内分离到致病菌株X-1-06909,采用生理生化鉴定结合16S rRNA基因序列的系统发育学分析确定该菌株的系统发育地位。同时采用琼脂扩散法对抗菌类药物的敏感性进行测定。【结果】菌株X-1-06909与Aeromonas veronii ATCC 35624T的16S rRNA基因序列相似性达99.6％;结合形态特征与生理生化测定结果,革兰氏阴性杆菌,具极生单鞭毛     

A Halophilic Vibrio Isolated from a Case of Chronic Cholecystitis

We found a halophilic vibrio in B bile from a 75-year-old female patient with chronic cholecystitis, and examined its biochemical characteristics. The organisms are gram-negative short rods or comma shaped, with some ring forms. They have a single polar flagellum, but no capsule. The strains can grow in peptone water with 1.0 to 4.0% NaCl, but not with no NaCl or 6.0% NaCl. The characteristics of the organisms are positive dextrose fermentation, catalase, oxidase, and ornithine decarboxylase, and negative lysine decarboxylase, arginine dihydrolase, and absence of gas from glucose. They are sensitive to 2,4-diamine-6,7-diisopropyl pteridine (0/129). These characteristics indicate that the isolated strain should be a halophilic vibrio. However, no growth on Salmonella-Shigella (SS), SS with added sucrose and bromcresol purple (SS-SB), MacConkey's or thiosulfate citrate bile salts (TCBS) agar plates was demonstrated. Nitrate reduction, Simmons' citrate agar, indole, o-nitrophenol-β-d-galactopyranoside (ONPG), motility and esculin hydrolysis were positive. Urease, gelatinase, Voges-Proskauer, phenylalanine deaminase and malonate reactions were negative. Acid was produced from amygdalin, arabinose, cellobiose, fructose, galactose, glucose, lactose, maltose, mannitol, salicin, starch, sucrose, trehalose, and xylose, but not from adonitol, dulcitol, inositol, mannose, melibiose, raffinose, rhamnose and sorbitol. From these characteristics the isolate is considered to be not identical with V. parahaemolyticus, V. cholerae, V. vulnificus or other vibrios. It can be presumed that this isolate represents another species of halophilic vibrio.     

Evaluation of Different Assay Systems for Identification of Environmental Aeromonas Strains

Important biochemical reactions in conventional tests were compared with counterpart reactions in two multiple test systems, API-20E (Analytab Products, Plainview, N.Y.) and Aeromonas hydrophila medium, to evaluate their accuracy for the identification of motile Aeromonas spp. isolated from fish. In a total of 49 Aeromonas spp. isolates and 10 A. hydrophila reference strains, false-negative or -positive reactions were detected in the Voges-Proskauer test, indole production, gelatinase activity, production of gas, fermentation of arabinose, and lysine decarboxylase reaction. A good correlation was found, among the three identification systems, for the fermentation of mannitol and inositol as well as for the arginine dihydrolase and ornithine decarboxylase tests. The failure of A. hydrophila medium in the detection of gas indicates that this medium is not entirely suitable for defining aerogenic or anaerogenic strains. From the results of the present study, we consider that of the identification method and taxonomic scheme to be adopted for environmental Aeromonas spp. must be standardized.     

Differentiation of Streptococcus lactis var. maltigenes from Other Lactic Streptococci

Strains of lactic streptococci isolated from samples of raw milk which had developed a malty aroma were subjected to the cultural, physiological, and serological tests commonly employed in the classification of streptococci. None of the strains could be differentiated from Streptococcus lactis by these tests. Resting cells of strains which produced an organoleptically detectable malty aroma when cultured in milk were usually found to possess an active α-ketoacid decarboxylase, indicating the presence of the mechanism responsible for the characteristic aroma production. This decarboxylase activity was either weak or nonexistent in the nonmalty strains, and no activity was detected in known strains of S. lactis, S. cremoris, or S. diacetilactis. The malty strains usually produced higher acidities in milk than did the nonmalty strains, and, in most instances, they developed a granular type of growth sediment in broth, as opposed to a viscid sediment. Many of them gave weakly positive Voges-Proskauer tests in glucose broth with or without added citrate and appeared to be somewhat more resistant to nisin than the nonmalty strains.     

The widespread occurrence of rutin glycosidase in fluorescent phytopathogenic pseudomonads

Two hundred and twelve strains representing 11 species of fluorescent pseudomonads along with an additional 198 strains isolated from the leaf and root surfaces of plants were tested for rutin glycosidase, on a mineral base medium supplemented with rutin and glucose. AH of the arginine dihydrolase negative phytopathogens (182 strains) with the exception of 12 of 12 strains of Pseudomonas syringae pv. glycina and one of 28 strains of P. syringae pv. phaseoticola showed rutin glycosidase activity whereas few of the arginine dihydrolase positive strains (22 of 228) were positive.     

Comparison of reagent-impregnated paper strips and conventional tests for distinguishing Escherichia from Aerobacter: correlation with colonial morphology

The means for distinguishing Escherichia from Aerobacter (Enterobacter) differ in laboratories and range from complete dependence on colonial reactions on typical gram-negative media to reliance on one or more of the classical indole, methyl red, Voges-Proskauer, citrate (IMViC) parameters. Three colonial types (one prejudged as Escherichia) of lactose-positive rods were catalogued on each of the most commonly used selective media, MacConkey Agar, Endo Agar, and E M B Agar. Each cultural type was presumptively diagnosed and then compared with the expected outcome of individual IMViC tests. The distribution of preliminary identifications was similar from growth patterns on MacConkey Agar and E M B Agar, but it differed markedly from Endo Agar. When organisms initially diagnosed by cultural methods were compared by single IMViC tests, it was found that for each colonial type one of the biochemical parameters was best suited. Thus, for those types initially considered Escherichia, the methyl red or Voges-Proskauer test results agreed most consistently; for other types, the citrate reaction was most satisfactory. In addition, when newly formulated reagent-impregnated paper strip methods for indole, Voges-Proskauer, and citrate were evaluated and compared to the standard methods, agreement was 97% for indole, 90% for Voges-Proskauer, and 95% for Simmons' citrate.     

Isolation, characterization, and U(VI)-reducing potential of a facultatively anaerobic, acid-resistant Bacterium from Low-pH, nitrate- and U(VI)-contaminated subsurface sediment and description of Salmonella subterranea sp. nov

A facultatively anaerobic, acid-resistant bacterium, designated strain FRCl, was isolated from a low-pH, nitrate- and U(VI)-contaminated subsurface sediment at site FW-024 at the Natural and Accelerated Bioremediation Research Field Research Center in Oak Ridge, Tenn. Strain FRCl was enriched at pH 4.5 in minimal medium with nitrate as the electron acceptor, hydrogen as the electron donor, and acetate as the carbon source. Clones with 16S ribosomal DNA (rDNA) sequences identical to the sequence of strain FRCl were also detected in a U(VI)-reducing enrichment culture derived from the same sediment. Cells of strain FRCl were gram-negative motile regular rods 2.0 to 3.4 micro m long and 0.7 to 0.9 microm in diameter. Strain FRCl was positive for indole production, by the methyl red test, and for ornithine decarboxylase; it was negative by the Voges-Proskauer test (for acetylmethylcarbinol production), for urea hydrolysis, for arginine dihydrolase, for lysine decarboxylase, for phenylalanine deaminase, for H(2)S production, and for gelatin hydrolysis. Strain FRCl was capable of using O(2), NO(3)(-), S(2)O(3)(2-), fumarate, and malate as terminal electron acceptors and of reducing U(VI) in the cell suspension. Analysis of the 16S rDNA sequence of the isolate indicated that this strain was 96.4% similar to Salmonella bongori and 96.3% similar to Enterobacter cloacae. Physiological and phylogenetic analyses suggested that strain FRCl belongs to the genus Salmonella and represents a new species, Salmonella subterranea sp. nov.     

Activities of Arginine Dihydrolase and Phosphatase in Streptococcus faecalis and Streptococcus faecium

Strains of Streptococcus faecalis and S. faecium are known to produce ammonia from arginine, but only S. faecalis couples the adenosine triphosphate (ATP) produced through the arginine dihydrolase pathway to growth processes. The specific activities of the arginine dihydrolase enzymes were found to be much lower in S. faecium (0.01 to 0.10) than in S. faecalis (0.24 to 1.60). Phosphatase activities in both strains were similar (up to 0.11), but equaled or exceeded the activities of the arginine dihydrolase enzymes in S. faecium. The failure of S. faecium to show increased growth in arginine media is explained on the basis of low activities of the arginine dihydrolase enzymes coupled with sufficient phosphatase activity to negate any benefit from ATP formed.     

Modification of sorbitol MacConkey medium containing cefixime and tellurite for isolation of Escherichia coli O157:H7 from radish sprouts

A modified version of sorbitol MacConkey medium containing cefixime and tellurite (CT-SMAC medium) was produced by adding salicin and 4-methylumbelliferyl-beta-D-galactopyranoside to CT-SMAC medium; this medium was designated CT-SSMAC medium and was used to isolate Escherichia coli O157:H7 from radish sprouts. Of 101 non-E. coli bacteria isolated from radish sprouts that produced colorless colonies similar to colonies of E. coli O157:H7 grown on CT-SMAC medium, 92 (91%) formed colonies that were red to pink or were beta-galactosidase negative and colorless on CT-SSMAC medium. On the other hand, colonies of E. coli O157:H7 strains were colorless and beta-galactosidase positive on CT-SSMAC medium. Our results suggest that CT-SSMAC medium is more selective than CT-SMAC medium for isolating E. coli O157:H7.     

Cholesterol-reducing bacterium from human feces.

An anaerobic, gram-positive diplobacillus that reduces cholesterol to coprostanol was isolated from human feces and rat cecal contents. The isolates closely resemble a cholesterol-reducing organism isolated by Eyssen et al. (H. Eyssen et al., Eur. J. Biochem. 36:412-421, 1973) from a rat's cecum. These organisms would not form colonies and were isolated and cultivated in an anaerobic medium containing homogenized pork brains (naturally high in cholesterol). These organisms require free or esterified cholesterol for growth. They were isolated by serially diluting feces or cecal contents and inoculating brain medium. Colony-forming organisms, which did not reduce cholesterol, were eliminated by addition of inhibitory agents to the brain medium cultures. This serial dilution procedure was performed until a pure culture of a cholesterol-reducing organism was obtained.     

Cholesterol-reducing bacterium from human feces.

An anaerobic, gram-positive diplobacillus that reduces cholesterol to coprostanol was isolated from human feces and rat cecal contents. The isolates closely resemble a cholesterol-reducing organism isolated by Eyssen et al. (H. Eyssen et al., Eur. J. Biochem. 36:412-421, 1973) from a rat's cecum. These organisms would not form colonies and were isolated and cultivated in an anaerobic medium containing homogenized pork brains (naturally high in cholesterol). These organisms require free or esterified cholesterol for growth. They were isolated by serially diluting feces or cecal contents and inoculating brain medium. Colony-forming organisms, which did not reduce cholesterol, were eliminated by addition of inhibitory agents to the brain medium cultures. This serial dilution procedure was performed until a pure culture of a cholesterol-reducing organism was obtained.     

Presence of the arginine dihydrolase pathway in Mycoplasma

Barile, Michael F. (Division of Biologics Standards, National Institutes of Health, Bethesda, Md.), Robert T. Schimke, and Donald B. Riggs. Presence of the arginine dihydrolase pathway in Mycoplasma. J. Bacteriol. 91:189-192. 1966.-The presence of the arginine dihydrolase pathway was examined in 61 Mycoplasma strains representing at least 18 Mycoplasma species isolated from nine different sources: human, bovine, avian, murine, swine, goat, canine, sewage, and tissue cell culture origin. Some species were represented by only one or two strains. Different strains of the same species gave the same results. Ten species (56%) were positive. Many nonpathogenic Mycoplasma species (M. hominis, type 1 and 2, M. fermentans, M. salivarium, and M. gallinarum) were positive, whereas most pathogenic species (M. pneumoniae, M. gallisepticum, M. neurolyticum, and M. hyorhinis) were negative. The presence of arginine dihydrolase activity among Mycoplasma species may prove to be useful for purposes of identification and classification.     

Characterization of Pseudomonas fuscovaginae and Differentiation from Other Fluorescent Pseudomonads Occurring on Rice in Burundi

In various pathogenicity, serological, physiological and biochemical tests, performed in Belgium and Japan, the Pseudomonas fuscovaginae strains associated above 1,350 m elevation in Burundi with sheath brown rot of rice, rusty seed and black, stripes on seedlings, were found to be similar to reference strains of this pathogen from Japan. The same bacteria was detected on rice seeds imported from Asia to Burundi. Beside the serological characteristics, P. fuscovaginae can be differentiated from other oxidase and arginine dihydrolase positive non-pathogenic fluorescent pseudomonads, also isolated from lesions on rice seedlings, by the simultaneous occurrence of no production of 2-ketogluconate, acid production from trehalose, but not from inositol. Occasionally, other symptoms inducing, oxidase positive, fluorescent pseudomonads, different from any described species, were isolated from rice seedlings and sheath rot in Burundi.     

THE USE OF GLUCOSE INORGANIC SALTS MEDIA IN THE CLASSIFICATION OF THE COLI-AEROGENES BACTERIA. I. THE METHYL RED AND VOGES-PROSKAUER REACTIONS

SUMMARY: A chemically defined glucose ammonium phosphate medium gave methy red and Voges-Proskauer reactions which were superior to those in glucose peptone phosphate. Optimum condition for both tests require a starting pH of 6·8 and incubation for 3 days at 30°. The medium gave a negative correlation between the two reactions with 34 out of 35 strains that were positive to both tests in the peptone medium. The addition of glutamic acid helped to eliminate doubtful positive M. R. reactions but seemed to suppress acetylmethylcarbinol production by weakly V.-P. positive strains.     

Comparative Study of the Efficacy of Seven Paper-Reagent Strips and Conventional Biochemical Tests in Identifying Gram-negative Organisms

Gram-nagative organisms were tested with commercially available reagentimpregnated strips (PATHO-TEC). Of the 291 strains, all were tested by using seven paper tests and their conventional counterparts. Excellent correlation was obtained with the oxidase, phenylalanine-deaminase, and Voges-Proskauer tests. Indole tests made on liquid medium cultures also gave complete correlation, but some false-negative results with indole-positive Proteus strains were obtained when growth from solid medium was tested by the strip method. Paper strip urease tests were positive within 2 hr with all Klebsiella and some Serratia, Herellea, and Citrobacter strains as well as with Proteus strains. Approximately 15% of citrate strip test results differed from those of the conventional tests, and reproducibility was poor on retest. The lysine decarboxylase strip test showed a number of discrepancies and posed problems of interpretation and readability. Paper reagent strip methods are simple and convenient and merit further development to increase the specificity of those which depend on pH change up to that achieved with the Voges-Proskauer, oxidase, phenylalanine, and indole methods.     

Histidine Decarboxylaseless Mutants of Lactobacillus 30a: Isolation and Growth Properties

Mutants of Lactobacillus 30a deficient in their ability to form an inducible histidine decarboxylase (EC 4.1.1.22) were selected by plating nitrosoguanidine-treated cultures on a medium containing histidine and methyl red. Wild-type organisms produce histamine, thus raising the pH and forming yellow colonies; mutant colonies remain red. In the presence of added histidine, decarboxylase-producing cultures grow more heavily than mutant cultures when the initial pH of the growth medium is low or when the lactic acid produced lowers the pH to growth-limiting values. Addition of the decarboxylation products, histamine and carbon dioxide, did not favor growth in crude medium.     

Histamine production by Klebsiella pneumoniae and an incident of scombroid fish poisoning.

A histamine-producing strain of Klebsiella pneumoniae was isolated from a sample of tuna sashimi implicated in an outbreak of scombroid fish poisoning. None of the other nine gram-negative bacterial strains isolated from the tuna sashimi was capable of equivalent histamine production. Bacterial histamine production was monitored in a tuna fish infusion broth (TFIB), and the implicated K. pneumoniae was capable of producing 442 mg of histamine per 100 g of tuna in TFIB in 7 h under controlled incubation conditions. Only 12 of 50 other K. pneumoniae strains, representing 5 distinct biochemical types, which had been originally isolated from foods, were able to produce such levels of histamine in TFIB. No correlation was found between histamine production and other biochemical characteristics or antibiotic resistance. Of the 12 histamine-producing strains, 11 belonged to type 2, which is characterized as indole negative with positive reactions in the urea and Voges-Proskauer tests. However, only 50% of the type 2 strains examined produced high levels of histamine in TFIB. Additionally, the implicated K. pneumoniae strain and one other strain belonged to type 1, which is characterized by positive reactions in the indole, urea, and Voges-Proskauer tests.     

Histamine production by Klebsiella pneumoniae and an incident of scombroid fish poisoning.

A histamine-producing strain of Klebsiella pneumoniae was isolated from a sample of tuna sashimi implicated in an outbreak of scombroid fish poisoning. None of the other nine gram-negative bacterial strains isolated from the tuna sashimi was capable of equivalent histamine production. Bacterial histamine production was monitored in a tuna fish infusion broth (TFIB), and the implicated K. pneumoniae was capable of producing 442 mg of histamine per 100 g of tuna in TFIB in 7 h under controlled incubation conditions. Only 12 of 50 other K. pneumoniae strains, representing 5 distinct biochemical types, which had been originally isolated from foods, were able to produce such levels of histamine in TFIB. No correlation was found between histamine production and other biochemical characteristics or antibiotic resistance. Of the 12 histamine-producing strains, 11 belonged to type 2, which is characterized as indole negative with positive reactions in the urea and Voges-Proskauer tests. However, only 50% of the type 2 strains examined produced high levels of histamine in TFIB. Additionally, the implicated K. pneumoniae strain and one other strain belonged to type 1, which is characterized by positive reactions in the indole, urea, and Voges-Proskauer tests.     

一株产红色素菌株及对其红色素结构的鉴定

从土壤中分离到一株产红色素的细菌H31,根据该菌株的16S rDNA序列与GenBank中已有序列比对的结果,并结合菌落形态和常规生理生化鉴定方法对该菌株进行鉴定,结果表明:该菌在细菌分类学上属于肠杆菌科,其与黏质沙雷氏菌(Serratia marcescens)同源性最高,但该菌株生理生化实验中的赖氨酸脱羧酶、鸟氨酸脱羧酶以及精氨酸双水解酶实验与报道的S. marcescens的结果不一致,为一株新的黏质沙雷氏菌S. marcescens H31。通过紫外光谱、质谱和核磁共振等方法分析,确定其产生的红色素为灵菌红素。