bluuebunny/crossref_metadata_2025 huggingface dataset:
Induction of Accelerated Sporangial Lysis by Basic Peptide Antibiotics. A Novel Method of Preparation of Free Spores of Bacilli
Authors: VINTER V. , ŜŤASTNÁ JANA
Published: March 2008

An accelerated release of free spores from sporangia of Bacillus cereus NCIB‐8122 and Bacillus subtilis SMYW was induced by the addition of the basic peptide antibiotics, polymyxin B or colistin (100 μg/ml), to sporangia formed in liquid Bactopeptone medium. Destruction of sporangial cell walls of B. cereus prelabelled with 3H‐4‐diaminopimelic acid commenced shortly after the addition of either antibiotic, the label being gradually released into the medium. Normal free spores were released following the addition of antibiotics to sporangia containing refractile spores (stages IV‐V of sporogenesis). Earlier additions induced the lysis of both compartments of the sporangium, accompanied by the release of already‐synthesized dipicolinic acid and alreadyaccumulated 45calcium. The heat resistance and germination ability of spores released in the presence of the antibiotics were the same as those of control spores released by long‐term spontaneous lysis of sporangia. Similar effects of the antibiotics were observed with B. subtilis SMYW. Results obtained were used firstly for fast preparation of relatively clean free spores and secondly for the characterization of the developmental stage of sporogenesis at which the spore becomes independent of the maternal cell. It reaches this property at the end of stage IV and during stage V.
A Note on Scanning Electron Microscopy of Micro‐organisms associated with the Kefir Granule
Authors: BOTTAZZI V. , BIANCHI F.
Published: March 2008

Scanning electron microscopy was used to examine the micro‐organisms on kefir granules. The most richly colonized part was that nearest to the exterior of the granule; it contained mainly bacteria and a few yeasts. The latter increased towards the centre of the granule where few bacteria were present. The kefir grain has a spongy fibrillar structure with a reticular lamellar matrix and a fibre mass which, especially in the centre of the grain, shows branching and interconnections with long cordons.
The Recovery of Sublethally Injured Escherichia coli from Frozen Meat
Authors: MACKEY B. M. , DERRICK CHRISTINE M. , THOMAS JOSEPHINE A.
Published: March 2008

Sublethal injury to Escherichia coli, measured as the inability of surviving cells to grow on media containing bile salts, was monitored during frozen storage on meat at —5, —10 and —20° C. More rapid increases in injury occurred at the higher subzero temperatures and log phase cells were more susceptible than those in the stationary phase of growth. Repair of injury in non‐selective liquid media took between 2 and 6 h at 25° and was often accompanied by an increase in total viable count. Incubation for a fixed period in broth was, therefore, unsuitable for the quantitative recovery of freeze‐injured Esch. coli. Resuscitation on membrane filters avoided confusing repair of injury with multiplication of uninjured or repaired cells. The mean recovery of injured cells following incubation on membranes for 4 h at 35°C on tryptone soya agar, was 94%.
Numerical Taxonomy of some Marine Pseudomonads and Alteromonads*
Authors: GRAY P. ALISON , STEWART D. J.
Published: March 2008

Thirty‐one marine pseudomonads and alteromonads isolated from fish and water samples taken in the North Sea or the seas off north Norway, and five isolated from water samples taken off Hawaii were subjected to numerical phenetic analysis using 98 characters. Thirty of the 31 strains from northern waters were grouped into four clusters: two of these contained only high GC strains (60–62 mol%), the other two contained all the low GC strains (41.5–49 mol%) and one high GC strain (NCMB 127). No clustering was obtained with the three high GC strains (55.8–63 mol%) nor the two low GC strains (43.2 and 45.6 mol%) from Hawaiian waters.
Comparison of the Effects of Liquid Medium Repair and the Incorporation of Catalase in MacConkey Type Media on the Recovery of Enterobacteriaceae Sublethally Stressed by Freezing
Authors: MOSSEL D. A. A. , VELDMAN A. , EELDERINK INEKE
Published: March 2008

Nine pure cultures of species of Enterobacteriaceae were stressed by rapid freezing in tryptone soya broth (TSB) to — 22°C and subsequent storage at that temperature for 7 d. About one to two log cycles kill and at least one additional log cycle sublethal impairment was achieved. Numbers of colonies of these cultures in poured plates of violet red bile glucose (VRBG) agar, with 67 u/ml of catalase added at 47°C, were only slightly higher than those in plain VRBG, both incubated overnight at 30°C. Two hours incubation of TSB suspensions at 17–25° C resulted in almost complete restoration of the ability of cells to develop colonies in VRBG, without, however, leading to any significant multiplication.

Similar experiments with 32 samples of frozen minced meat, 27 samples of frozen surface water, 18 of frozen chicken liver and 14 of fresh sausage substantiated the results obtained in the studies on pure cultures.

In the experiments with the nine pure cultures the influence of the nutrient composition of the solid enumeration media: ‘minimal’ agar, TSB agar (TSBA) and Mueller‐Hinton agar with Polyvitex nutrient supplement (MHA), on the recovery of Enterobacteriaceae stressed by freezing was also studied. Colony numbers in TSBA and MHA were virtually identical. The glucose mineral salts medium led to lower recovery, indicating that so‐called ‘minimal medium recovery’ of stressed bacterial populations is not a common phenomenon.
Physiological Properties of Nitrogen‐scavenging Bacteria from the Marine Environment
Authors: JONES K. L. , RHODES‐ROBERTS MURIELE.
Published: March 2008

Nine selected strains of marine bacteria from the marine environment, although taxonomically heterogeneous in character, exhibited a capacity for prolonged growth on ‘nitrogen‐free’ media; only one strain, a Klebsiella sp., fixed dinitrogen under any of a considerable range of test conditions. The non‐nitrogen‐fixing bacteria were able to scavenge low levels of nitrogenous materials, principally ammonia, from the atmosphere. Contrary to previous suggestions, this growth did not have an abnormally low cellular protein and nitrogen content. Some strains with apparently low intracellular protein contents, as determined on a cellular dry weight basis, showed accumulations of carbonaceous storage products which distorted the cytochemical analyses. Representative strains grown in chemostat culture showed a high affinity (i.e. low Ks values—0.35–0.52 μmol/1) for the NH4+ ion, compared with Escherichia coli (1.75 μmol/1) and preliminary studies of their glutamine synthetases suggested that the affinities (Km values—0.25–0.29 μmol/1) of this enzyme for hydroxylamine were similar to the few values reported for other marine bacteria.
Candida guilliermondii, an Actidione‐resistant Yeast from Wine*
Authors: ETHIRAJ S. , ONKARAYYA H. , SURESH E. R.
Published: March 2008

Candida guilliermondii var. guilliermondii, a yeast which showed high resistance to actidione, was isolated from a red wine sample. Growth in 5000 parts/106of actidione was equal to that of the control. Sorbic acid and sodium benzoate were most effective in checking the growth at 250 parts/106but growth occurred at 750 parts/106of potassium metabisulphite. Fermentation of glucose, galactose, sucrose and raffinose was not inhibited in the presence of 1000 parts/106actidione. This is the first report on the occurrence of actidione‐resistant yeasts in the genus Candida and on the isolation of C. guilliermondii var. guilliermondii from wine.
Microbiological Parameters for Differentiating between Coastal and Open Waters in the Northern Baltic Proper and the Gulf of Finland
Authors: VÄÄTÄNEN P.
Published: March 2008

The abundance of selected types of micro‐organisms was compared between seven sites in inshore and offshore areas in the northern Baltic proper and at the entrance to the Gulf of Finland. The aim was to find out which of the microbiological parameters indicate terrestrial and littoral influences on the sites investigated and which of them indicate offshore conditions. During four cruises in 1977–78, samples were collected from 1‐0 m depth, within one or a few days, at five offshore and two inshore sites.

Microbial numbers decreased consistently with increasing distance from the shore. The influence of terrestrial runoff, outflows from littoral areas and sediments was clear in the two Tvärminne inshore areas but not in the Ajax area situated about 10 km seaward of the outermost skerries of the Tvärminne archipelago. The influence of these factors was most distinctly indicated by viable bacteria at 18°C and polymyxin‐resistant bacteria, rods and bacterial spores. Offshore characteristics were indicated by vibrios and bacteria obviously in a starved state. Proteolytic bacteria and yeasts did not indicate either of these conditions.
Establishment of Ureolytic Staphylococci in the Rumen of Gnotobiotic Lambs
Authors: BARR MARGARET E. J. , MANN S. O. , RICHARDSON A. J. , STEWART C. S. , WALLACE R. J.
Published: March 2008

Six strains of ureolytic staphylococci isolated from rumen digesta and the rumen wall of conventionally reared sheep were inoculated per os into two germ‐free lambs. High numbers of staphylococci established in rumen fluid, and urease activity and normal NH3 and urea concentrations were maintained for approximately 4 weeks until slaughter. Staphylococci were found also to be associated with the rumen wall, conferring urease activity on this tissue.
Haemagglutinins and Fimbriae in Different Serotypes and Biotypes of Yersinia enterocolitica
Authors: MACLAGAN R. M. , OLD D. C.
Published: March 2008

When cultured in static broth at 20°C, 46 of 115 strains of Yersinia enterocolitica, diverse in biotype and serotype, produced a broad‐spectrum mannose‐resistant (MR) adhesin that agglutinated the erythrocytes of all of 10 animal species examined. The production of haemagglutinin (HA) was associated with the presence of fimbriae of S nm diameter. Culture of HA+ strains at 37° resulted in the disappearance of haemagglutinating ability and loss of fimbrial production. Strains of Y. enterocolitica with K1 antigen produced an MR adhesin that agglutinated only fowl erythrocytes and was associated with fimbriae of 4–4.5 nm diameter. None of 14 strains of Y. pseudotuberculosis was haemagglutinating.
A Numerical Taxonomic Study of Pseudomonas‐like Bacteria Isolated from Fish in Southeastern Queensland and their Association with Spoilage
Authors: GILLESPIE N. C.
Published: March 2008

Pseudomonas‐like bacteria isolated from fresh and spoiling fish in southeastern Queensland were subjected to a wide range of physiological and nutritional tests. The results of these tests, together with those of 20 named strains, were analysed numerically, resulting in the formation of 11 groups. Most of the isolates clustered into group 1 and group 2 which also contained the bulk of the strains able to produce spoilage odours when grown in a tryptic digest of fish muscle at 2°C. Almost all of the group 1 organisms produced sulphydryl type odours, had only 50 mol % G + C and were identified as strains of Alteromonas putrefaciens which were deficient in the ability to produce H2S detectable in Peptone Iron Agar. Certain of the group 2 strains produced fruity and sulphydryl type odours, but these organisms were not distinguishable from other strains in this group not producing odours. Group 2 strains were highly related to Pseudomonas fragi and were intermediate in properties between Ps. fluorescens and Ps. putida. The remaining nine minor groups contained few organisms able to produce spoilage odours.
Taxonomy and Description of Vibrio fluvialis sp. nov. (Synonym Group F Vibrios, Group EF6)
Authors: LEE J. V. , SHREAD P. , FURNISS A. L. , BRYANT T. N.
Published: March 2008

A numerical taxonomic study has been carried out to establish the relationship of group F to other biochemically similar organisms within the family Vibrionaceae. A total of 154 strains were examined including 59 of group F. Out of 114 characters determined for each strain 100 were used to compute average Euclidean distances between strains. Four methods of clustering were used, all of which gave very similar results.

Strains resembling Vibrio anguillarum fell into clusters corresponding to V. anguillarum, Beneckea nereida and a previously unrecognized group, phenon 5. Strains of the Aeromonas hydrophila/punctata group formed a heterogenous phenon within which certain subdivisions, perhaps artificial, could be discerned.

Group F strains all fell in one closely‐knit cluster distinct from all the species of Vibrio, Aeromonas, Plesiomonas and Photobacteriwn studied. Group F strains could be divided into two biovars, I and II. Both biovars are present in aquatic, particularly estuarine, environments throughout the world but biovar I strains have also been isolated from humans with diarrhoea. It is concluded that group F is a synonym of group EF6 and that the strains within these groups should be classified in a new species named Vibrio fluvialis. The type strain is NCTC 11327.
The Ecology of Chloramphenicol‐Resistance in Salmonella typhimurium and Escherichia coli in Calves with Endemic Salmonella Infection
Authors: LINTON A. H. , TIMONEY J. F. , HINTON M.
Published: March 2008

A batch of 40 calves intensively reared on a milk replacer diet was monitored over 34 d for salmonella and Escherichia coli excretion patterns. A total of 1055 Esch. coli was isolated on unsupplemented bile lactose agar (BLA), and 537 on BLA supplemented with chloramphenicol, from 10 selected calves. The antibiotic resistance pattern and O‐serogroup were determined for each isolate.

Salmonella typhimurium phage type DT 193 carrying six R determinants was detected in five calves on intake; after 14 d 28 were excreting the organism but by the time the calves left the farm (34 d) only a small number were found to be excreting the organism indicating that the infection was self limiting by about six weeks of age. In contrast, multiply resistant Esch. coli were being excreted in increasing numbers with time. Of the isolates on BLA 95.5% were resistant to at least one antibacterial agent and many were resistant to up to six agents. An unusually high proportion (49%) was resistant to chloramphenicol and this R determinant was frequently associated with R determinants for at least streptomycin, sulphonamide and tetracycline, a combination regularly present in the salmonellas. Chloramphenicol resistance is carried on an H2 plasmid in Salmonella typhimurium phage type 193 and it was found that 11% of 146 randomly selected isolates of Esch. coli, carrying the same range of R determinants, were infected with an H2 plasmid. H2 plasmids were found in a number of O‐sero‐groups of Esch. coli and chloramphenicol resistance was present in 37 O‐serogroups. It is suggested that transfer from the salmonellas to Esch. coli possibly took place before the calves entered the farm and the transconjugants were selected by the antibiotics used on the farm. Subsequent transfer between Esch. coli could explain the wide distribution of chloramphenicol‐resistance in many serogroups. The transfer of H2 plasmids is thermosensitive and no transfer could be demonstrated in vivo but occurred readily in voided faeces held at 28°C. The importance of Esch. coli as a reservoir of chloramphenicol resistance and the public health implications are discussed.
Resistance of Serratia marcescens to Hydrogen Peroxide
Authors: BAYLISS CATHERINE E. , WAITES W. M.
Published: March 2008

Irradiation with ultraviolet (u.v.) light (71 J/m2) reduced the viable count of suspenrsions of Serratia marcescens, grown in a glycerol‐salts defined medium, to five in 104 cells. Subsequent incubation of irradiated cells in hydrogen peroxide failed to decrease the survivors, but u.v. irradiation in the presence of hydrogen peroxide reduced the viable count to fewer than two in 106 cells. Cells grown in defined medium with added iron had more measurable catalase activity and were more resistant to hydrogen peroxide alone and to simultaneous treatment with u.v. irradiation and hydrogen peroxide. Cells grown in a non‐defined medium contained little iron and measurable catalase activity but were more resistant to hydrogen peroxide. Treatment with toluene, heat killing or sonication increased the catalase activity detected in all cell suspensions and showed that resistance to hydrogen peroxide and to u.v. irradiation in hydrogen peroxide was related to the total catalase activity within cells.
Resistance and Structure of Spores of Bacillus subtilis
Authors: BAYLISS CATHERINE E. , WAITES W. M. , KING N. R.
Published: March 2008

Spores of Bacillus subtilis NCDO 2130 were produced on five different media and their structure and resistance to chemicals, to heat and to ultraviolet (uv) irradiation compared. Resistance to one chemical was not necessarily related to resistance to another, to uv irradiation or to heat. Spores with the smallest protoplasts and largest cortices were most resistant to heat, while the least resistant were those in which the protoplasts became electron dense after staining and which had the lowest concentrations of calcium and dipicolinic acid.
Rapid Serotyping of Bacteria of the ‘Bacteroides fragilis’ group by Direct Immunofluorescence, Serotype Specific Conjugates
Authors: MEISEL‐MIKOLSACZYK FELICJA , GRZELAK‐PUCZYNSKA IRENA
Published: March 2008

Six ‘Bacteroides fragilis’ serotype‐specific fluorescein‐labelled antisera were prepared and used in the direct immunofluorescence test (IFT). The method permitted the rapid detection of serotypes within the ‘B. fragilis’ group. The specificity is connected with the phenol‐water extracted endotoxins.
Amino Acid Enhancement of Recovery in Dry‐heat Damaged Spores of Bacillus subtilis
Authors: GURNEY TESSA R. , QUESNEL L.B.
Published: March 2008

Spores of Bacillus subtilis MD2 and var. niger were dry‐heat damaged at 150°, 160° and 170°C and recovered on media of increasing complexity. The greater the heat dose the more marked was the effect of amino acid supplements on recovery. For strain MD2 maximum germination and outgrowth of unheated spores could be obtained on a minimal salts + glucose medium with alanine, aspartic acid, glycine and methionine; the latter three amino acids served to enhance growth, not germination. The recovery of heat‐damaged spores was significantly increased by adding valine plus isoleucine or arginine or glutamine. The increase was probably due to the use of valine and isoleucine as substrates of NAD‐linked dehydrogenases to generate reducing power and serve as NH3‐donor, initiating germination in spores which were unable to germinate as a result of inactivation of alanine dehydrogenase. Valine or isoleucine added singly suppressed recovery by feedback inhibition of the pathways to both these amino acids during outgrowth.
Correlation of Growth Depression of Chicks with the Presence of Streptococcus faecium in the Gut
Authors: HOUGHTON S. B. , FULLER R. , COATES M. E.
Published: March 2008

Although Streptococcus faecium appeared rapidly in the gut of chicks reared in fumigated premises, the growth of the birds was not always depressed. Growth depression was often associated with the growth of Strep.faecium in the duodenum. The growth depression produced by mono‐association of germ‐free chicks with Strep. faecium grown aerobically was variable. A less variable response which was statistically significant was obtained by growing the inoculum anaerobically.
Separation of Non‐filamentous Micro‐organisms from Soil by Density Gradient Centrifugation in Percoll
Authors: MARTIN N. J. , MACDONALD R. M.
Published: March 2008

Soil suspensions were homogenized, and desorbed non‐filamentous micro‐organisms were concentrated in a minimum volume of buffer by low speed centrifugation. The cells were separated from inanimate material by flotation at the interface between the buffer and a silica sol/polyvinyl pyrrolidone density gradient medium (Percoll). Cell suspensions were removed from the interface and fractionated according to density by high speed centrifugation on discriminating density gradients in Percoll.

Preliminary experiments indicated that most non‐filamentous soil micro‐organisms had densities in the range 1.081–1.123 g%sol;ml while Rhizobium isolated from crushed root nodules on Percoll was split into two bands of densities 1.081–1.110 and 1.041–1.073 g/ml. The lighter cells were the more pleomorphic.

The efficiency of extraction of cells from soil was governed by the extent of their desorption from inanimate particles. As rigorous desorption procedures damage cells, extraction efficiencies were low; 10–20% of cells counted microscopically in soil were recovered from density gradients. Electron microscopy of soil micro‐organisms isolated by this method showed an unusual range of surface ornamentations on cell‐like structures of bacterial dimensions.
An Agar Medium for the Differential Enumeration of Streptococcus thermophilus and Lactobacillus bulgaricus in Yoghurt
Authors: BRACQUART P.
Published: March 2008

A differential medium has been developed for the simultaneous enumeration of Lactobacillus bulgaricus and Streptococcus thermophilus from yoghurt. After incubating in a ‘candle jar’ at 42°C, a first count can usually be made at 24 h.
A Simple Sensitive Method for Determining Staphylococcal Thermonuclease in Cheese
Authors: IBRAHIM G. F.
Published: March 2008

A simple quantitative method is described for the determination of staphylococcal thermostable nuclease in cheese. The method does not require concentration or purification of the nuclease prior to determination because of the increased sensitivity of the assay (0.5 ng/ml). Assay results of cheddar cheese made from pasteurized milk inoculated with enterotoxin‐A producing Staphylococcus aureus strains demonstrated the sensitivity and reliability of the method for indicating the presence of Staph. aureus at concentrations of ≥ 1.4 × 106/g of cheese.
Potassium Fluxes on Hyperosmotic Shock and the Effect of Phenol and Bronopol (2‐bromo‐2‐nitropropan‐1,3‐diol) on Deplasmolysis of Pseudomonas aeruginosa
Authors: KROLL R. G. , ANAGNOSTOPOULOS G. D.
Published: March 2008

Potassium fluxes and the effect of phenol and bronopol on deplasmolysis of Pseudomonas aeruginosa were followed in sucrose and glycerol plasmolysing systems.

In sucrose, K+ uptake related to the solute concentration. Proline increased the rate and overall K+ uptake, the latter by a factor of three. It was concluded that there was no rigid maximum in the accumulation of intracellular K+ as long as intracellular neutrality in electrical charges was maintained.

In glycerol, K+ uptake was parallel with glycerol penetration. The process was reversed, however, on equilibration of glycerol. This suggested that glycerol inhibited K+ retention against a concentration gradient rather than that K+ was excluded as a consequence of the osmotic established steady state. This view was enforced by the fact that the reversal of K+ uptake occurred in 20 and 30% glycerol but not in 10%.

Phenol and bronopol did not affect deplasmolysis in glycerol significantly, although some effect on K+ uptake and glycerol permeability could be seen. In the sucrose system, phenol acted according to its mode of action generally accepted, i.e. inhibiting deplasmolysis at low and allowing solute penetration at higher concentrations, whereas very high concentrations caused coagulation of the cytoplasm. Bronopol inhibited deplasmolysis, except at very low concentrations. Proline did not prevent the inhibition of deplasmolysis in either of the solute systems, except at the very low bronopol concentrations where the deplasmolysis rate only was affected.
Serological Activity of ‘Bacteroides fragilis’ Endotoxins—Strains Isolated in Poland
Authors: MEISEL‐MIKOŁAJCZYK FEUCJA , ROKOSZ ALICJA , GRZELAK‐PUCZYŃSKA IRENA
Published: March 2008

Antigens were extracted by the phenol‐water method from each of the 11 strains of ‘Bacteroides fragilis’ species, isolated from clinical material. Nine of these strains had been identified by the direct immunofluorescence test (IFT) as ‘B. fragilis spp. fragilis’, and two as ‘B. fragilis ssp. thetaiotaomicrori’.

These antigens were then used in the immunodiffusion test (ID), performed with antisera of six serotypes. Results of the ID test agreed in nine cases with those of IFT. An antigenic heterogeneity among strains of ‘B. fragilis ssp. fragilis’ strains was noted. Antigens prepared in the same way from two strains did not react in the ID test with any of the antisera used although cells were positively stained in the IFT by specific anti‐‘B. fragilis’ serotype conjugates.
The Effect of Temperature, Pressure and Chlorine Concentration of Spray Washing Water on Numbers of Bacteria on Lamb Carcases
Authors: KELLY C. A. , DEMPSTER J. F. , MCLOUGHLIN A. J.
Published: March 2008

Combined analysis of three experiments showed that when lamb carcases with initial bacterial numbers of between logi103.29 and 4.22/cm2 were spray washed, statistically significant reductions in bacterial numbers of log10O.5 were obtained when the spray wash water temperature was > 57°C, and reductions of log101.0 were obtained when the temperature was ≥ 80°C. Reductions at all temperatures were enhanced by log100.66 when the water contained 30 µg/ml chlorine, but increasing the concentration to 450 µg/ml reduced bacterial numbers only by a further log100–29. At highly contaminated sites increasing the duration of spraying from 30 to 120 s significantly increased the reductions obtained when water containing added chlorine was used. Reductions in bacterial numbers after spray washing with pressures of 3.5, 5.6. 7.7 kg/cm2 were not significantly different.
The Effect of pH Adjustment on the Microbiology of Chicken Scald‐tank Water with Particular Reference to the Death Rate of Salmonellas
Authors: HUMPHREY T. J. , LANNING D. G. , BERESFORD DENISE
Published: March 2008

In laboratory experiments adjustment of the pH of chicken scald‐tank water to 9.0 ± 0.2 lowered the D52°C value of a strain of Salmonella typhimurium from 34.5 to 1.25 min. Factory trials where the scald water was maintained at pH 9.0 ± 0.2 for the after‐lunch period showed that both the total bacterial population and the number of coli‐aerogenes organisms were substantially reduced. Addition of sodium hydroxide also increased the rate of accumulation of total dry matter in the water. Sodium carbonate was as effective as NaOH in increasing the death rate of Salm. typhimurium and would appear to be a suitable alternative.
Effect of Hyperbaric Carbon Dioxide Pressure on the Microbial Flora of Pork Stored at 4 or 14°C
Authors: BLICKSTAD E. , ENFORS S.‐O. , MOLIN G.
Published: March 2008

Changes in the microbial flora of pork stored at 4 or 14°C were studied in 5 atm CO2, 1 atm CO2 or 1 atm air. The time needed for the total aerobic count at 4°C to reach 5 × 106 organisms/cm2 was about three times longer in 5 atm CO2 than in 1 atm CO2, and about 15 times longer in 5 atm CO2 than in air. At 14°C there was no difference in growth rate between 5 atm CO2 and 1 atm CO2. No off‐odour was detected after storage in 5 atm CO2 for 14 d, but the pork in 1 atm CO2 (6 d) was organoleptically unacceptable.

The predominant organisms on the pork from the processing line were: Flavobacterium spp., Acinetobacter calcoaceticus, Pseudomonas spp., Micrococcus spp. and Moraxella spp. After aerobic storage at 4°C (8 d) or 14°C (3 d) more than 90% of the flora consisted of Pseudomonas spp. At 4°C all Pseudomonas spp. were of the non‐fluorescent type, whilst at 14°C 32% were Ps. putida and Ps. fluorescens. After storage in 1 atm CO2Lactobacillus spp. represented 66% of the flora at 14°C (6 d) and 100% at 4°C (40 d), with L. xylosus dominating. After storage in 5 atm CO2Lactobacillus spp. constituted the total flora at both temperatures with L. lactis (14°C) and L. xylosus (4°C) dominating.

It was concluded that high partial pressures of CO2 have a considerable shelf‐life prolonging effect by (i) selecting the microflora towards Lactobacillus spp. and (ii) reducing the growth rate of these Lactobacillus spp. The controlling and growth inhibitory effect of CO2 was promoted by reduced temperatures.
The Antimicrobial Susceptibility Test: A Comparison of the Results of Four Methods
Authors: DEGENER J. E. , THONUS I. P. , MICHEL M. F.
Published: March 2008

A comparison of the results of the antimicrobial susceptibility tests by the agar‐dilution method, the agar‐diffusion method, the Autobac‐1 system and the MS2 system has been made in a number of Escherichia coli and Staphylococcus aureus strains. With the agar‐dilution method as a reference the agar‐diffusion method and the MS2 system showed mostly satisfactory scores. With the Autobac‐1 system, Esch. coli strains gave several insufficient scores with some antibiotics. A study of the distribution of minimal inhibitory concentrations against the strains has enabled the explanation of some of the discrepancies that were observed. Furthermore, the influence of two different sets of interpretive criteria on the outcome of the results has been studied.
Semi‐automated counting of bacteria and somatic cells in milk using epifluorescence microscopy and television image analysis
Authors: Pettipher G.L. , Rodrigues Ubaldina M.
Published: March 2008

An epifluorescent microscope fitted with a ‘Chalnicon’ closed circuit television camera linked to an Optomax System III image analyser was used to count bacteria and somatic cells on membrane filters prepared from milk by the direct epifluorescent filter technique (DEFT). For both bacteria and somatic cells, the semi‐automated DEFT count of low count milk exceeded the visual DEFT count but this difference became proportionately less as the count increased. There was close agreement between the semi‐automated and visual DEFT counts over the range 105‐5 times 106/ml for bacteria and 3 times 105‐5 times 106/ml for somatic cells. The semi‐automated DEFT count of bacteria and somatic cells correlated well with the plate count and Coulter count respectively, with correlation coefficients of 0.83 and 0.81.
The effect of spray washing on the development of bacterial numbers and storage life of lamb carcases
Authors: Kelly C.A. , Lynch B. , McLoughlin A.J.
Published: March 2008

Total bacterial numbers at the most highly contaminated sites on lamb carcases (in the crutch region and adjacent to the abdominal incision) were significantly reduced to log10 3.3/cm2 when spray washed with unchlorinated water at 80°C and to log10 2.8 when water at 80°C containing 450 μg/ml chlorine was used, whereas numbers on carcases which were cloth cleaned or spray washed with water at 10°C remained at approximately log10 4.0. During refrigerated storage, however, carcases treated by all methods developed similar numbers of bacteria and had the same storage life, evidently because spray washing did not affect numbers of bacteria on the diaphragm. Although initial numbers of bacteria at this site were low (log10 2.9), their numbers, and also the amount of slime, increased more rapidly there than at other sites. In addition, spray washing did not significantly affect numbers of Pseudomonas spp or Brochothrix thermosphacta, which accounted for <1% of the microflora after slaughter at each site but whose numbers were between log10 6.1 and 7.5/cm2 when carcases were rejected as spoiled.
Identification of bacteria of dairy origin using miniaturized test‐systems
Authors: Griffiths M.W. , Phillips J.D.
Published: March 2008

One hundred and forty‐four isolates of dairy origin were identified using a number of commercially available test kits. Agreement between these kits was acceptable for assignment of isolates to genera, but there was some variation between the kits for the identification of the isolates at specific level. The reasons for these variations are discussed. In terms of cost, ease of performance and accuracy, the identification systems manufactured by Roche Products Ltd (viz. the Oxi/Ferm tube and the Enterotube) are considered to be the best suited to the routine identification of dairy micro‐organisms.
Further development of a bacteriocin typing system for Clostridium perfringens
Authors: Scott H.G. , Mahony D.E.
Published: March 2008

The specificity of typing Clostridium perfringens with bacteriocins was improved by adding new bacteriocins and deleting others from the original typing set of ten. A total of 516 new isolates of Cl. perfringens were screened for bacteriocin production and, of these, 162 strains (31%) were found to be producers. The sensitivity patterns obtained by testing 40 bacteriocins against 200 isolates of Cl. perfringens were recorded and the data subjected to a computer analysis. A total of 18 bacteriocins capable of dividing the 200 isolates into 98 typing patterns was selected. The repro‐ducibility of the new system was tested by performing three sequential typings of 60 strains of Cl. perfringens. No variation was found in 73% of the strains, while a further 16% of the strains demonstrated a change in sensitivity to only one bacteriocin. Common serological types of Cl. perfringens were divisible into subtypes based upon both their ability to produce bacteriocins and their sensitivity to bacteriocins, suggesting a useful role for bacteriocin typing in conjunction with an already well‐established tool for typing Cl. perfringens.
Recovery of heat‐injured Citrobacter freundii cells
Authors: Verrips C.T. , Kwast R.H.
Published: March 2008

The influence of various factors in the recovery process of heat‐injured cells of Citrobacter freundii has been studied. In particular the temperature of the liquid recovery medium and the residence time of the cells in this medium are important. Cells heated in media with a high osmotic pressure are better recovered in low osmotic liquid recovery media. The influence of the temperature of the solid recovery medium on the decimal reduction time for Ctbt. freundii cells strongly suggests that the number of critical sites to be inactivated before the cell wall be lethally injured also depends on the recovery conditions.
A note on ginger blotch, a new bacterial disease of the cultivated mushroom, Agaricus bisporus
Authors: Wong W.C. , Fletcher J.T. , Unsworth B.A. , Preece T.F.
Published: March 2008

Ginger blotch, a new bacterial disease of the cultivated mushroom, Agaricus bisporus, is described from farms in the UK. The symptoms are distinct from the classical blotch disease caused by Pseudomonas tolaasii. The causative organism has been isolated and identified as a new member of the Pseudomonas fluorescens complex which can be distinguished from Pseudomonas tolaasii by several simple tests.
Transformation of cholic acid by Clostridium bifermentans
Authors: Archer R.H. , Maddox I.S. , Chong R.
Published: March 2008

Suspensions of washed, resting‐stage cells of Clostridium bifermentans were incubated with cholic acid under a variety of conditions in an attempt to manipulate the competing 7α‐dehydroxylation and 7α‐dehydrogenation reactions. Important variables thus identified were then tested in batch fermentation. Sodium thioglycollate was observed to inhibit dehydrogenation and to delay dehydroxylation. Zinc ion inhibited both dehydrogenation and dehydroxylation. In the presence of EDTA, near quantitative 7α‐dehydrogenation was achieved with no associated dehydroxylation. Finally, the presence of air in the fermenter headspace enhanced both transformations, possibly through an effect on the redox potential of the medium.
The inhibition of vegetative cell outgrowth and division from spores of Bacillus cereus T by hen egg albumen
Authors: Tranter H.S. , Board R.G.
Published: March 2008

Spores of Bacillus cereus T germinated and formed vegetative cells in Tryptone Soya broth (TSB), pH 9‐0 and 7‐4 at 30oC. Spores germinated but did not form vegetative cells when suspended in hen egg white (pH 9‐0) supplemented with L‐alanine and inosine. Using a split image eyepiece, the volumes of germinating spores in egg white were seen to increase as a result of increases in both length and breadth. In TSB at the same pH, the major volume increase resulted from a progressive increase in cell length. Egg white supplemented with L‐alanine and inosine (pH 7‐6 30oC) allowed limited outgrowth to occur but the vegetative cells differed in morphology to those in TSB. Fe(NH4)2(SO4)2.6H2O overcame the inhibition of outgrowth in egg white at pH 7–8 but not in egg white at pH 9‐1. Solutions containing trace elements, growth factors and casamino acids could not replace iron in this respect. Sporulation occurred in egg white only when iron was present.
The effect of the synergy between sterigmatocystin and a fungal metabolite on Bacillus subtilis
Authors: Perry M.J. , Adlard M.W. , Holt G.
Published: March 2008

Component I (a metabolite isolated from Aspergillus nidulans) was shown to increase the cellular uptake of sterigmatocystin by Bacillus subtilis. The uptake of sterigmatocystin by bacterial cells caused the induction of aberrant cellular forms and inhibited DNA synthesis with little effect on the synthesis of RNA and protein.
Examination of bovine faeces for the isolation and identification of Clostridium species
Authors: Princewell T.J.T. , Agba M.I.
Published: March 2008

A total of 162 faecal samples was collected from individual cattle on ten farms from three states of Nigeria. These samples yielded 333 clostridial isolates out of which 295 (88.6%) were identified; the remaining 38 (11.4%) could not be readily identified at species level. The species most frequently isolated was Clostridium perfringens representing 63.7% of the isolates and the next highest was Cl. bifermentans with a frequency of 12.6%. The other species identified were less frequently isolated. No farm yielded all the species isolated. The farm with the highest distribution of the species of Clostridium was the Livestock Investigation Centre, Vom, Plateau State, with a frequency distribution of 62% of the species isolated. In none of the other farms was the distribution up to 50% frequency.
Effect of sulphasalazine on the human intestinal flora
Authors: Hazenberg M.P. , Barker M. , Both‐Patoir H.C. , Embden J.G.H. Ruseler van , Schroder A.M.
Published: March 2008

Sulphasalazine is commonly used to treat patients with ulcerative colitis but the mode of action is still unexplained. To investigate a possible antibacterial effect of sulphasalazine, the faecal flora composition was studied in patients with ulcerative colitis and in mice harbouring a human intestinal flora. Patients on sulphasalazine were found to have an intestinal flora that was completely resistant to sulphapyri‐dine. Oral administration of sulphasalazine did not influence the composition of the human flora in mice.
The uptake of bacteria and amino acids by Ophryoscolex caudatus, Diploplastron affine and some other rumen Entodiniomorphid protozoa
Authors: Coleman G. S. , Reynolds Diana J.
Published: March 2008

The rate of uptake of mixed rumen bacteria and free amino acids by washed suspensions of seven species of rumen ciliate protozoa has been followed. By assuming that the behaviour of these protozoa was the same under these conditions as during growth it was shown that Ophryoscolex caudatus could obtain the amino acids for growth by the engulfment of rumen bacteria. However, all the cellulolytic protozoa studied (Diploplastron affine, Diplodinium anacanthum, Diplodinium anisacanthum, Enoploplastron triloricatum, Eremoplastron bovis and Ostracodinium obtusum bilobum) were unable to obtain sufficient amino acids from either source to grow at even 25% of the maximum rate and it is postulated that they might utilize plant protein. O. caudatus grown in vitro did not engulf Klebsiella aerogenes or Escherichia coli but took up other bacteria and a rumen yeast at rates of up to 54000 organisms/protozoon/h from a population density of 109/ml. When grown in vivo it was more selective and engulfed mixed rumen bacteria at only 10% of the rate obtained with protozoa grown in vitro. D. affine grown in vitro did not engulf Bacteroides ruminicola, Esch. coli, Kl. aerogenes or Proteus mirabilis but took up mixed rumen bacteria from a population of 109/ml at a rate of 2200 bacteria/ protozoon/h.
Types and properties of some bacteria isolated from hypersaline soils
Authors: Quesada E. , Ventosa A. , Rodriguez‐Valera F. , Ramos‐Cormenzana A.
Published: March 2008

Five rhizosphere soil samples from the dominant xerophytic plants, and nearby root‐free soil samples were obtained from a series of hypersaline soils (5.0–10.7% NaCl) from sites near Alicante in Spain. Physico‐chemical analyses were made, and the bacterial flora estimated using three different plating media. Counts from rhizosphere soil were always significantly higher than those from root‐free soils. A total of 211 strains isolated were purified and identified to genus level; 12 could not be classified. The range of salt concentration allowing growth was determined for each isolate, but this did not correlate with the salt content of the soil habitat. Most isolates appeared to be typical moderate halophiles (with optimum growth between 5 and 15% salts), but about half of them grew on normal media with only 0.9% naCl, a notable difference from moderately halophilic aquatic bacteria. Extreme halophiles were rare but this may have been due to an insufficient incubation period.
Attempt at gene reversion of a desired phenotype as a rescue against strain degeneration
Authors: Kole H.K. , Samanta A.K. , Goswami S.K. , Bose S.K.
Published: March 2008

Mutagenesis may lead to the production of antibiotic producer revertant derivatives from a non‐producer degenerate originally active against skin pathogens. All of the producer revertants examined in the present study were phenotypically different from the producer parental mutant. Most of the revertants were active against plant pathogens, the test fungus used for screening being a plant pathogen. The selective pressure of the test fungus for isolation of revertants may prove very useful in producing a revertant derivative of a desired phenotype.
Chemostat adaptation of Escherichia coli B/r/1 to low water activity
Authors: Anagnostopoulos G.D. , Dhavises G.
Published: March 2008

Chemostat cultures of Escherichia coli B/r/1 under conditions of glucose limitation in a salts medium at high water activity (aw of 0.999) and at an aw of 0.987, controlled by NaCl, have been compared. The system was run at dilution rates above 0.035 h‐1. The results suggested that the organism adapted to the lower aw of the medium as no significant change was observed in the energy requirement for maintenance, although the maximum molar growth yield for glucose decreased by 23.2%. Such cultures showed also a shorter lag and a higher growth rate in batch at an aw of 0.987, as compared with cultures initiated with an unadapted (aw of 0.999) inoculum.
Taxonomic studies on ‘Streptococcuspluton’
Authors: Bailey L. , Collins M.D.
Published: March 2008

Strains of ‘Streptococcus pluton’ isolated from honeybee larvae with European foul‐brood from widely separate parts of the world represent a relatively homogeneous taxon; all are related serologically. Added cysteine or cystine make a variety of otherwise unsuitable nitrogen sources satisfactory for all strains, which all have the same fastidious culture requirements. Test strains lack respiratory quinones and possess a Group A peptidoglycan based upon lysine, primarily straight‐chain and cyclopropane‐ring fatty acids, and a DNA base composition of 29–30 G + C mol %. Results obtained indicate that the strains presently designated ‘Strep. pluton’ should constitute the nucleus of a new genus.
Reclassification of ‘Streptococcus pluton’ (White) in a new genus Melissococcus, as Melissococcus pluton nom. rev.; comb. nov.
Authors: Bailey L. , Collins M.D.
Published: March 2008

‘Streptococcus pluton’ (White) differs to such an extent from the type species of Streptococcus, Strep. pyogenes (Rosenbach), that it cannot be retained in this genus. Culture, biochemical and chemical data indicate that ‘Strep, pluton’ is a distinct taxon worthy of generic status. A new genus, Melissococcus, is described to contain one species Melissococcus pluton (White) nom. rev.; comb. nov. The type strain is M. pluton NCDO 2443.
The water activity of common liquid bacteriological media
Authors: Chirife J. , Favetto G. , Scorza O.C.
Published: March 2008

The water activities (aw) of 27 (21 different) bacteriological media were determined. It was found that aw values of most media were above the range reported in the literature as optimal for rates of growth of many bacteria.
Assessment of immunofluorescence measurements of individual bacteria in direct and indirect assays for Bacillus anthracis and Bacillus cereus spores
Authors: Phillips A.P. , Martin K.L.
Published: March 2008

A microfluorometer constructed by the addition of fibre optics to a standard fluorescence microscope has been used in immunofluorescence assays for spores of Bacillus anthracis and B. cereus. Variation in the fluorescence measurements of individual anthrax spores increased as the amount of conjugate bound increased. Proportionality of photodetector voltage and amount of bound conjugate is suggested by results with a dual fluorescein/tritium‐labelled antibody. The maximum fluorescence signal which could be achieved in indirect assays was virtually independent of the purity of the antispore antibody. Evidence is presented that the molecular loading of conjugate on the spore surface is similar in the direct and indirect assays.
An improved method using acetyl‐coenzyme A regeneration for the enzymic inactivation of aminoglycosides prior to sterility testing
Authors: Breeze A.S. , Simpson Ann M.
Published: March 2008

Aminoglycoside antibiotics may be inactivated by acetylation before they are tested for sterility. A method is described for producing acetyl‐coenzyme A in situ which enhances the level of inactivation and reduces the cost of the procedure. Phosphotransacetylase was prepared from Escherichia coli B and its suitability for recycling acetyl‐coenzyme A to be used in acetylating aminoglycosides was investigated. The whole recycling mixture was successfully lyophilized which makes the procedure suitable for use in both large and small laboratories for sterility testing of aminoglycoside antibiotics instead of the more common method of membrane filtration.
A note on novobiocin in XLD and HE agars: the optimum levels required in two commercial sources of media to improve isolation of salmonellas
Authors: Restaino L. , Komatsu K.K. , Syracuse M.J.
Published: March 2008

Media containing novobiocin were tested for their selectivity for salmonelias. The optimum concentrations of novobiocin that gave the greatest percentage recovery without altering the colony morphology were 7 μg/ml in XLD Agar (Oxoid) and 40 μg/ml in HE Agar (Oxoid). At these concentrations some strains of Proteus mirabilis were suppressed and those that did survive did not produce hydrogen sulphide. The addition of novobiocin altered the colony morphology of Citrobacter freundii and Escherichia coli. Salmonella typhi was not used in this investigation and isolation of this pathogen on novobiocin supplemented media is questionable.
A note on a selective medium for the isolation of cutaneous propionibacteria
Authors: Cove J.H. , Eady E. Anne
Published: March 2008

A selective medium containing 6 μg/ml furoxone was developed for routine isolation of cutaneous propionibacteria from mixed floras including staphylococci.