bluuebunny/crossref_metadata_2025 huggingface dataset:
Characteristics of some unclassifiable strains of staphylococci isolated from goats and sheep
Authors: Adegoke G.O.
Published: March 2008

Adegoke, G.O. 1985. Characteristics of some unclassifiable strains of staphylococci isolated from goats and sheep. Journal of Applied Bacteriology59, 257–262.

Fourteen strains of catalase‐positive, Gram‐positive and coagulase‐negative cocci that were sensitive to 20 μg/ml of furazolidone were isolated from goats and sheep. Two of the strains had glycerol with glucose teichoic acids whilst another possessed glycerol, glucose, glucosamine and acetylglucosamine teichoic acids. Six strains had peptidoglycan type L‐Lys‐Ala‐Gly4 peculiar to Staphylococcus sciuri and Staph. lentus but other phenotypic characters were different from those of Staph. sciuri and Staph. lentus. The guanine plus cytosine (G + C) content of the DNA determined for three of the strains examined ranged from 32.9–34.6 mol %. The coagulase‐positive staphylococcal strain of caprine origin examined had glycerol and glucosarnine teichoic acids in addition to peptidogylcan type L‐Lys‐Gly5–6. The characteristics of the strains of staphylococci described herein are different from those already described in the literature.
Mycobacterium senegalense from bovines in Eastern Nigeria
Authors: Mohan Krishna
Published: March 2008

Mohan, K. 1985. Mycobacterium senegalense from bovines in Eastern Nigeria. Journal of Applied Bacteriology59, 277–281.

Detailed characteristics of three mycobacterial strains sharing important properties of Mycobacterium senegalense are described. Their physiological properties were compared with those of a typical M. senegalense strain described by Chamoiseau (1979), six strains of M. senegalense and one typical strain of M. fortuitum from the culture collection of Institute of Microbiology, Rutgers. The three Nigerian strains exhibited minor variations in their physiological properties when compared with other strains of M. senegalense. Unlike the strain of Chamoiseau the Nigerian strains did not utilize benzoate or citrate. The strains were also different from the other six strains of M. senegalense by utilizing trehalose and in failing to produce acid in mannitol. Unlike earlier isolates of M. senegalense the Nigerian strains were not from cases of bovine farcy but from cases with pathological manifestations of pulmonary tuberculosis. They appeared to be intermediate strains between M. senegalense and M. fortuitum. These results raise doubts on the justification for giving specific rank to M. senegalense.
The cytochrome c oxidase test for the rapid detection of psychrotrophic bacteria in milk
Authors: Kroll R.G.
Published: March 2008

A new, rapid, simple and cheap method for the detection of the predominant psychrotrophic bacteria in raw and pasteurized milks is described, using tetramethyl‐p‐phenylene‐diamine dihydrochloride to detect cytochrome c oxidase which in general is not present in the non‐psychrotrophic bacterial milk flora. The test is sensitive to samples containing over 104 organisms/ml. Correlation coefficients of 0.92 and 0.84 between dye oxidation and viable counts for pasteurized and raw milk samples, respectively, were found.
A note on the stability of Rappaport—Vassiliadis enrichment medium
Authors: Vassiliadis P. , Mavrommati C.H , Efstratiou M. , Chronas G.
Published: March 2008

After pre‐enrichment in buffered peptone water, 376 samples from chicken carcasses, minced meat, pork sausages, faeces of healthy pigs and sewage‐polluted seawater were enriched in Rappaport—Vassiliadis medium prepared either 4 d or 6–7 months before use. It was observed that the two media were equally effective in detecting Salmonella spp., (82 positive samples with each medium) and in their ability to inhibit competing organisms.
A note on yeast growth in media used for the cultivation of lactobacilli
Authors: Rose Sally A.
Published: March 2008

Yeast species found in mayonnaise‐based salads are capable of growth in media used for the isolation of lactobacilli. Many counts of lactobacilli from such products may, therefore, inadvertently include counts of yeasts. A method is presented whereby the use of media with and without chloramphenicol makes it possible to deduce a differential count of bacteria. It was not possible to prevent yeast growth in de Man, Rogosa and Sharpe agar by the addition of cycloheximide since many isolates were resistant to it.
The effect of properties of dried preparations of sulphide iron motility (SIM) agar on the results of motility readings
Authors: Visser Ingrid J.R. , Jaisly F. , Mossel D.A.A.
Published: March 2008

Three internationally marketed dried preparations of SIM agar were inoculated with 130 strains of fermentative Gram‐negative bacteria, isolated from foods. No less than 24–53% of false negative results, depending on batch number, were obtained with preparations marketed by one manufacturer. Quality monitoring of this medium before use in diagnostic work is therefore imperative.
Time course of volatile compound formation during refrigerated storage of naturally contaminated beef in air
Authors: Dainty R.H. , Edwards R.A. , Hibbard C.M.
Published: March 2008

The microbial flora of naturally contaminated beef stored in air was similar to that frequently recorded for meat stored under gas permeable films. Compounds produced as a result of microbial growth were acetoin, diacetyl, 3‐methyl‐l‐butanol, 2‐methyl‐1‐propanol, ethyl esters of acetic, propionic, butyric, isovaleric and hexanoic acids, methane thiol, dimethylsulphide, dimethyl disulphide, 1‐undecene and 1,4‐undecadiene. The first four compounds, which are known end‐products of Brochothrix thermosphacta metabolism, we consistently detected at earlier stages of storage than the others, all of which have been shown to be produced by Pseudomonas spp. A pattern of odour development consistent with the chemical changes was also observed.
A note on the survival of Legionella pneumophila in stagnant tap water
Authors: Schofield Geraldine M.
Published: March 2008

Tap water, from an experimental hot water system, containing a known virulent strain of Legionella pneumophila was stored in screw‐capped bottles for 14 months. Viable counts showed survival of L. pneumophila and at least three other bacterial species. This reinforces the view that L. pneumophila can survive in stagnant water foatively long periods of time.
A microprocessor‐controlled photometer for monitoring microbial growth in multi‐welled plates
Authors: Thomas D. Susan , Henschke P.A. , Garland B. , Tucknott O.G.
Published: March 2008

Multi‐welled microtitre plates provide a convenient means of handling ‘large block’ multifactorial experiments with microbial cultures. An inexpensive instrument, termed a ‘Biophotometer’, has been designed to monitor microbial growth in each well, by transmitted light measurements. Optional microcomputer control is employed to facilitate scanning of plates and data handling. A unique method for agitating cultures is incorporated into the system. Typical results are presented to illustrate the versatility of this system.
Estimated numbers of bacteria in samples from non‐homogeneous bodies of water: how should MPN and membrane filtration results be reported?
Authors: Tillett Hilary E. , Coleman R.
Published: March 2008

Published tables of Most Probable Numbers (MPN) used in water bacteriology make the assumption that the sample is representative of a large body of water in which the bacteria are randomly distributed. MPN values for certain dilution series are calculated without making this assumption. Although the actual MPN values obtained in this way are similar to those published, a question remains about how the MPN result should be reported. Because it is an estimate of the likely number and not a count of the organisms, a range of other plausible values could be given for that particular water sample. It is suggested that for certain results, where there are close contenders for the description ‘MPN’, a numerical range should be given in preference to a single MPN value. A further range of ‘possible’ numerical values is also suggested to replace the published approximate confidence intervals which are inappropriate for non‐homogeneous waters. Confidence intervals for the numbers of bacteria calculated from membrane filtration may be estimated from this sample only if it can be assumed that there is random distribution of bacteria in that water source. Water sources likely to contain bacteria in varying density (other than purely random variation) include pre‐treatment waters intended for drinking, and bathing waters. The only way to study the distribution of bacteria in such water sources is to take a series of samples appropriately planned in place and time.
A note on the use of 3‐section plates for the estimation of the numbers of bacteria and to obtain isolated colonies in 1 day
Authors: Lee W.H. , McClain D. , Szymanski C.D.
Published: March 2008

By streaking with an open loop and then swabbing a 4–5 cm2 area on 3‐section agar plates, it is possible to obtain isolated colonies and to estimate bacterial densities from 100 to 107/ml on the swabbed area.
The persistence of Legionella pneumophila in non‐sterile, sterile and artificial hard waters and their growth pattern on tap washer fittings
Authors: Schofield Geraldine M. , Locci R.
Published: March 2008

Simultaneous experiments were performed with sterilized and non‐sterile water and an artificial hard water. After seeding with an environmental isolate of Legionella pneumophila numbers in the sterile land hard water decreased rapidly and colonization of various tap washer fittings failed to take place. Adhesion and growth of an environmental isolate of L. pneumophila to washers in non‐sterile tap water was followed over a 4‐month period with fluorescein‐labelled antibody and by scanning electron microscopy. After adherence the individual cells appeared to divide to form chains which spread over the surfaces. Organisms other than legionellas were also present and a complex colonization matt was formed which was embedded in a protective coat of slime and debris. The numbers of L. pneumophila recovered from the water were highest between 4 and 7 weeks but they could still be cultivated after 4 months.
Characterization of microbial populations in polluted marine sediments
Authors: Parkes R.J. , Taylor J.
Published: March 2008

The sediment environment is both heterogeneous and complex, and so too are the bacterial communities which develop within it. There are no simple, universal techniques available to characterize sediment microbial communities. Each method, even ones purporting to measure the same parameter (e.g. total bacterial biomass by ATP, LPS or direct counts plus volume estimates), tends to quantify a specific aspect of the microbial community. Hence, methods used to characterize bacterial populations within sediments need to be chosen carefully and with full awareness of the principles and limitations involved. An important point which also has to be considered is that biomass estimates, which may be equatable to activity for higher organisms, do not necessarily reflect metabolic activity when applied to bacteria (Meyer‐Reil et al. 1978).

A large number of techniques for quantifying microbial populations require that the basic data be multiplied by conversion factors in order to obtain information which is both understandable and comparable with other data. These factors have to be used with caution, as they are often derived from laboratory isolates which may have very different properties and compositions from sediment bacteria. Also, as bacterial types change with depth within a sediment (Fig. 4), so too may the appropriate conversion factors. In this context there is obviously a need for more basic physiological information concerning sediment bacteria. In addition, if the characterization of bacterial populations within sediments is to play an effective role in the study of the impact of pollutants on the system in general, information is needed about the variability of microbial populations in both polluted and non‐polluted sediments.

With all the problems associated with quantifying bacterial activity and populations within sediments it is tempting to ask the question 'Why bother to include micro‐organisms in any pollution study? The answer is that because they are the organisms that will respond rapidly to even small environmental changes, they provide the potential for positive action to be taken before damage to the higher trophic levels becomes irreversible.
Niacin assay by monitoring changes in electrical conductance caused by microbial growth
Authors: Einarsson H. , Snygg B. G.
Published: March 2008

A computerized Malthus 128 H Growth Analyser was used to determine the changes in conductance produced by growth of a niacin‐dependent strain of Lacto‐bacillus plantarum ATCC 8014 in different concentrations of niacin in the growth medium. Changes in conductance varied linearly with the niacin concentration in the range 5–50 ng/ml. The time required to complete a test is inversely related to the inoculum size, and results can be obtained after 6 h.
Prediction of the keeping quality of pasteurized milk by the detection of cytochrome c oxidase
Authors: Kroll R. G. , Rodrigues Ubaldina M.
Published: March 2008

The keeping quality (KQ) of pasteurized milk samples stored at 5°C and 10°C was satisfactorily predicted after 18 h pre‐incubation with 0.05% benzalkonium chloride at 20°C, by estimating the numbers of Gram‐negative psychrotrophic bacteria using the simple, cheap and rapid (5 min) assay of cytochrome c oxidase. Correlation coefficients for the relationship between cytochrome c oxidase activity at 20°C and KQ at 5°C or 10°C of ‐0.89 and ‐0.84 respectively were obtained. The method correctly predicted the KQ of more than 89% of the samples of pasteurized milk. The assay was not satisfactory for use on samples after pre‐incubation at 30°C.
A carbon source‐dependent antimetabolite sensitivity test in Bacillus megaterium B71 for isolation of ethionine resistant mutants
Authors: Roy S. K. , Mishra A. K. , Nanda Geeta
Published: March 2008

Alteration of carbon sources significantly altered the analogue sensitivity of Bacillus megaterium B71. DL‐Ethionine (ETN) was highly inhibitory with glucose, mannitol, sucrose, citrate, glycerol and arabinose. DL‐Norleucine, L‐homoserine and S(2′‐aminoethyl)‐L‐cysteine were either highly inhibitory, slightly inhibitory or non‐inhibitory depending on the carbon sources used. Maltose markedly overcame the inhibitory effect of ETN in liquid culture. Uninhibited growth was poor on citrate and arabinose when compared with other carbon sources. Six carbon sources showing comparable growth were used to determine minimum inhibitory concentrations (MIC) of the analogues. The MIC of ETN was highest (450 μg/ml) with maltose and lowest (4 μg/ml) with mannitol. ETN sensitivity was inversely related to the endogenous L‐methionine pool size, and was relatively low with mannitol which was used to isolate ETN resistant mutants of B. megaterium B71. The best mutant BUE‐118 produced 435 μg/ml of L‐methionine.
A note on the control of sulphate‐reducing bacteria in seawater by u.v. irradiation
Authors: Wardell J. N. , Battersby N. S. , Stewart D. J.
Published: March 2008

Continuous and batch cultures of marine sulphate‐reducing bacteria (SRB) in North Sea water were irradiated with 110000 to 329500 μWs/cm2 of ultraviolet radiation (wavelength 253.7 nm) with a commercial u.v. sterilizing unit. A 100% kill was obtained with logarithmic cultures of Desulfovibrio desulfuricans NCIMB 8400 at population densities of 10–104/ml. A >99.99% kill was obtained with a mixture (ca 105/ml) of batch grown Desulfovibrio spp. and oilfield SRB enrichments. Ultraviolet irradiation was less effective against the indigenous heterotrophic bacteria in the seawater (ca 90% kill).
Effects of dietary chlortetracycline on the antimicrobial resistance of broiler faecal Streptococcaceae
Authors: Molitoris E. , Krichevsky M. I. , Fagerberg D. J. , Quarles C. L.
Published: March 2008

A breeder flock and a control group of progeny birds were fed antimicrobial‐free rations; a second group of progeny received rations supplemented with 50 g chlortetracycline (Ctc)/ton. Effects of dietary Ctc on the distribution of species and biotypes of faecal Gram‐positive cocci and their relative resistance to 12 antimicrobial agents were studied. Antimicrobial resistance (AMR) pattern diversity and modal AMR patterns were determined for bacterial species common to all three groups. Numerical taxonomic analysis placed 1321 (97%) of 1360 isolates into eight species or biotypes. The largest cluster (n= 659, 48%) was a biotype of Streptococcus faecalis. Three clusters were biotypes of Streptococcus faecium and contained 580 isolates (42%). The isolates were susceptible to ampicillin and almost uniformly resistant to methicillin, neomycin, streptomycin, sulfadiazine and tetracycline. There were 54 and 47 different AMR patterns, including 0 to 11 and 1 to 11 resistance determinants, in isolates from control and Ctc‐fed birds, respectively. Modal AMR patterns for Strep. faecalis and one biotype of Strep. faecium were very similar for all three groups of birds. However, modal patterns in a second biotype of Strep. faecium varied considerably for all three groups. Interpretation of AMR pattern diversities were equivocal among biotypes from both progeny groups. The variable distribution of isolates, proportions of resistant strains, modal patterns and diversity indices among the progeny were probably due to their exposure to different environmental sources of bacteria.
Nitrogen metabolism in Aspergillus parasiticus NRRL 3240 and A. flavus NRRL 3537 in relation to aflatoxin production
Authors: Bhatnagar R. K. , Ahmad S. , Mukerji K. G. , Venkitasubramanian T. A.
Published: March 2008

The relationship between nitrogen assimilation, metabolism and aflatoxin formation has been investigated in a toxigenic and a non‐toxigenic strain of Aspergillus parasiticus. Ammonia from the medium is mainly assimilated via NADP‐requiring glutamate dehydrogenase. During growth NAD‐requiring glutamate dehydrogenase followed an inverse pattern of activity with respect to NADP glutamate dehydrogenase. Alpha‐ketoglutarate, the product of NAD glutamate dehydrogenase, stimulated acetate incorporation into aflatoxins. Glutamine synthetase, ornithine transcarbamylase, both utilizing glutamate as substrate were assayed under different growth conditions. An important regulatory role for glutamine synthetase is suggested. The metabolic route of asparagine utilization was also investigated. Both the known pathways, glutamate oxaloacetate transaminase and glutamate pyruvate transaminase are operative simultaneously.
Semi‐log model for interpreting the results of swabbing surfaces naturally contaminated
Authors: Richard J. , Piton Christine
Published: March 2008

Two mathematical models for depicting microbial depletions during six consecutive swabbings of refrigerated tank wall and teat skin were tested. Although a second degree polynomial equation gave a better adjustment of the data, a first degree equation was preferred to calculate the total numbers of micro‐organisms possibly retrieved from surfaces by swabbing. This model was used for estimating the level of milk contamination by teat skin.
Identification and grouping of Clostridium botulinum strains by numerical analysis of their electrophoretic protein patterns
Authors: Bom I. J. , Smelt J. P. P. M. , Kersters K. , Verrips C. T.
Published: March 2008

Strains of Clostridium botulinum type A, type E and both non‐proteolytic and proteolytic types B and F were characterized by their electrophoretic protein patterns. As the protein pattern changes during sporulation, special attention was paid to the prevention of sporulation by selecting an appropriate medium (Strasdine's medium plus 1% w/v glucose) and a scheme of repeated subculturing. Ribosomal proteins, evolutionarily conservative and hence relatively similar in all types of bacteria, were removed to optimize the resolving power of the electrophoretic technique. Protein patterns were compared by computing correlation coefficients of normalized densitometric tracings. The method is highly reproducible and its resolving power is high: all protein patterns found were specific. The strains tested fall into two main groups: the proteolytic and the non‐proteolytic cluster. Type A strains form a separate subgroup within the proteolytic cluster, the same applies to type E strains within the non‐proteolytic group. Although time‐consuming for spore‐forming bacteria, this method is, to our knowledge, the only technique that recognizes individual strains of Cl. botulinum. For non‐spore‐forming micro‐organisms the method is certainly much simpler and hence even more valuable.
The adherence of Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli on cotton, polyester and their blends
Authors: Hsieh You‐Lo , Merry Joanne
Published: March 2008

The adherent behaviour of the Gram‐positive Staphylococcus aureus and Staphylococcus epidermidis and the Gram‐negative Escherichia coli on cotton, polyester and their blends through contact in aqueous suspensions was studied. Staphylococcus epidermidis was found to adhere to fabrics much more so than Staph. aureus. The adherence of both Staph. epidermidis and Staph. aureus to fabrics increased as the content of polyester fibres in the fabrics increased. The attachment of E. coli to all fabrics was very low and was not affected by the fibre contents. Total numbers of adherent bacteria on cotton and polyester fabrics were related directly to the concentrations of the bacterial suspensions. The extents of adherence, expressed by the percentage of adherent bacteria from the suspension, however, were independent of the concentration. The length of contact with bacteria was also found to affect the adherence of bacteria on fabrics studied.
Molecular relationships between trimethoprim R plasmids obtained from human and animal sources
Authors: Towner K. J. , Wise P. J. , Lewis M. J.
Published: March 2008

A total of 65 trimethoprim R plasmids (35 obtained from human strains and 30 from animal strains of Escherichia coli) were examined by the technique of restriction endonuclease fingerprinting. Plasmids belonging to incompatibility groups B, FII and 1Δ obtained from human and animal sources showed close similarities within each group. Plasmids belonging to incompatibility groups 1α and P were also obtained from both human and animal sources, but there was no conclusive evidence of close relationships within the groups. Restriction endonuclease fingerprinting was found to be useful for obtaining information about the epidemiology of R plasmids. Its main limitation in this study related to broad host range plasmids of the P incompatibility group, some of which contained very few sites susceptible to cleavage by the restriction endonucleases tested.
Evaluation of a commercial β‐glucuronidase test for the rapid and economical identification ofEscherichia coli
Authors: Pearez J. L. , Berrocal Clara I. , Berrocal L.
Published: March 2008

A commercial β‐glucuronidase (β‐GUR) test for the rapid and economical identification ofEscherichia coliwas evaluated. A total of 762 clinical strains and 228 environmental isolates were studied. More than 95% of theE. colistrains were found to be β‐GUR positive. Thirty‐one clinical isolates ofShigella sonnei, 10 ofEnterobacter cloacae, eight of Enterobacter aerogenes, nine ofCitrobacter freundiiand one ofSalmonella enteritidisalso gave positive results. The enzyme β‐GUR was also detected in two environmental strains ofE. cloacaeand oneC. freundii.A comparative study between the β‐GUR test and the conventional identification system was carried out in 233 consecutive isolates of lactose positive enterobacteria. Agreement was observed in 223 cases and 190E. colistrains were correctly identified using this test. Discrepancies were found in 10 cases: nineE. coliwere β‐GUR negative and oneC. freundiiwas β‐GUR positive.Escherichia coliwas the only species positive for both β‐GUR and indole tests. This procedure permits a rapid, easy, precise and inexpensive identification ofE. coli.β‐GUR positiveEnterobacterstrains have not previously been described.
Tunicamycin‐resistant mutants of Bacillus amyloliquefaciens are deficient in amylase, protease and penicillinase synthesis and have altered sensitivity to antibiotics and autolysis
Authors: Dias F. F. , Shaikh M.‐K. G. , Bhatt Y. B. , Modi D. C. , Subramanyam V. R.
Published: March 2008

Mutants of Bacillus amyloliquefaciens resistant to at least 10 μg/ml of tunicamycin were isolated and shown to be pleiotropic. The mutants were more resistant to streptomycin, chloramphenicol, kanamycin and neomycin than was the parent strain but less resistant to penicillin G and tetracycline. They were more autolytic, presumably due to an altered cell wall. The mutants produced reduced levels of amylase, penicillinase and both metal and serine protease besides having an enhanced sporulation frequency and being more motile.
Plasmids of Staphylococcus aureus associated with live and processed poultry
Authors: Thompson J. K. , Holding A. J.
Published: March 2008

A series of 23 strains of Staphylococcus aureus originally isolated from processed poultry was screened for the presence of plasmids. Plasmids were more common in strains of Staph. aureus characteristically associated with live poultry than with strains endemic in poultry plants and strains of human origin. Two plasmids with sizes of 1·65 and 18·2 kilobase pairs (kBp) were present in three strains considered typical of Staph. aureus forma specialis ‘altilis’ and two plasmids with sizes of 1·65 and 17 kBp were present in three of four strains of Staph. aureus var. gallinae. A 1·65 kBp plasmid was present in all seven strains of these poultry biotypes and in three of 14 ‘endemic’ strains. All the 1·65 kBp plasmids were shown by blot hybridization to share sequence homology. There was also some sequence homology between the 18·2 kBp and 17 kBp plasmids. These results were supported by restriction enzyme digest analyses. A study of cured derivatives of strain PS221 f.sp. ‘altilis’ suggested that the 18·2 kBp plasmid encoded the genetic determinant(s) responsible for caseolysis. Both the 1·65 and the 18·2 kBp plasmids also exerted an effect on the production of acid from lactose. In no other characteristic did cured strains resemble the plasmid‐free ‘endemic’ strains. This was therefore consistent with the notion that the genetic determinants associated with the cultural characteristics of endemic strains are chromosomally located.
A laboratory microcosm (artificial mouth) for the culture and continuous pH measurement of oral bacteria on surfaces
Authors: Hudson D. E. , Donoghue Helen D. , Perrons C. J.
Published: March 2008

A laboratory microcosm has been designed for the cultivation of bacteria on surfaces subjected to an adjustable supply of fluids. Bacteria are grown as a microbial film on halved premolar teeth, mounted back to back. Synthetic saliva is dropped slowly over the teeth throughout experiments. A nutrient supplement is provided at regular intervals. The drops of fluid retained by the teeth can be sampled for metabolic end‐products. Alternatively, a miniature glass electrode may be set into one half of a tooth assembly to monitor the pH continuously at the stagnation site between tooth segments. Up to six replicate culture flasks and six electrodes can be accommodated in a single experiment. Satisfactory electrode performance was maintained during 66 h experiments. In initial 48 h experiments, teeth were inoculated with Streptococcus rattus BHT or ‘Streptococcus mitior’ LPA‐1 in pure culture and provided with 1% (w/v) glucose for 1 h every 6 h. Bacteria produced typical responses to glucose feeds leading to the formation of ‘Stephan’‐like curves of pH‐fall. Under these conditions, ‘Strep. mitior’ was more acidogenic than Strep. rattus and the pattern of acid production was distinct for each organism.
Induced release of Bacillus spores from sporangia by sodium sulphate
Authors: Burnett A. M. , Jr. J. W. Ezzell , Singh J. , Jr. G. F. Zipperle , Doyle R. J.
Published: March 2008

Incubation of sporulating cultures of Bacillus anthracis, B. cereus, B. subtilis and B. thuringiensis in 1°0 mol/l sodium sulphate markedly increased the release of free spores from sporangia. It is postulated that the release of spores is due to activation of latent autolysins which hydrolyse sporangial cell walls. Sodium sulphate‐induced lysis of sporangia represents a novel and highly effective method for the recovery of spores from cultures of Bacillus species.
Resistance of Providencia stuartii to chlorhexidine: A consideration of the role of the inner membrane
Authors: Ismaeel Nashat , El‐Moug T. , Furr J. R. , Russell A. D.
Published: March 2008

Spheroplasts of three strains of Providencia stuartii (one sensitive, one moderately sensitive and one resistant to chlorhexidine) were induced by cefoxitin, glycine or a lysozyme‐tris‐EDTA combination, and their susceptibility to chlorhexidine‐induced lysis investigated. Maximum lysis of spheroplasts occurred at a low (2·5–5 μg/ml) concentration of chlorhexidine and was greatest with the most sensitive strain, Pv2. The possible role of the inner membrane in chlorhexidine resistance is considered in the light of the findings obtained.
Comparative adhesion of seven species of streptococci isolated from the blood of patients with sub‐acute bacterial endocarditis to fibrin‐platelet clots in vitro
Authors: Crawford I. , Russell C.
Published: March 2008

The adhesion to fibrin‐platelet clots in vitro of 21 strains of streptococci isolated from the blood of patients with sub‐acute bacterial endocarditis (SABE) was measured. The species, in order of greatest adhesion, were Streptococcus faecalis, Streptococcus mutans, Streptococcus milleri, Streptococcus sanguis, dextran‐positive Streptococcus mitior, dextran‐negative Streptococcus mitior and Streptococcus salivarius. Individual strains within species, however, cannot be assumed to be representative of their species and may exhibit unusually high or low adhesion. Adhesion depended upon both bacterial concentration and period of contact. There was no simple relationship between ability to adhere and liability to cause endocarditis. Formation of dextran did not increase adhesion. The streptococci were more adhesive than strains of Escherichia coli and Neisseria sicca and less adhesive than strains of Staphylococcus aureus and Streptococcus pyogenes.
A note on the effects of associated micro‐organisms on the growth and nitrogenase activity of the cyanobacterium Anabaena cylindrica
Authors: Love A. J. W. , Rawson D. M.
Published: March 2008

Pseudomonas spp., Micrococcus spp. and Fusarium oxysporum promote growth and nitrogenase activity in Anabaena cylindrica. Respiratory CO2 production by the microbial associate appears to be the main benefit to the cyanobacterium. Some stimulation of nitrogenase, however, appears to be due to other causes in associations with Pseudomonas and Fusarium.
Expression of an agrocin‐encoding plasmid of Agrobacterium tumefaciens in Rhizobium meliloti
Authors: Hendson Mavis , Thomson Jennifer A.
Published: March 2008

Plasmid RP4 was used to mobilize the agrocin 84‐encoding plasmid, pAg396, from Agrobacterium tumefaciens strain 396 to A. tumefaciens C58 and C58CI as well as Rhizobium meliloti. It was transferred to, but not stably maintained in, R. leguminosarum. It could not be transferred to R. lupini, R. japonicum or R. trifolii. Plasmid pAg396 did not segregate in R. meliloti and produced levels of agrocin comparable to the parental strain A. tumefaciens 396. The potential of agrocin producing R. meliloti in biological control of crown gall is being investigated.
Mechanisms of triple stress‐mediated damage in stationary phase cells of Salmonella typhimurium exposed to succinate‐acidified hypochlorite system at 5° C
Authors: Obafemi A. , Davies R.
Published: March 2008

Exposure for 20 min of stationary phase cells of Salmonella typhimurium to a combined triple stress system (TSS) treatment comprising hypochlorite derived 5 ppm free available chlorine in solution acidified with 1% succinate (pH 2·5) and at a chill shock temperature of 5°C resulted in symptoms of injury. Cells became sensitive to 40 μg/ml lysozyme, 50 μg/ml actinomycin D and 100 μg/ml ribonuclease B, to which control cells were resistant. Metabolic injury was indicated by reduction in colony forming ability of stressed cells on minimal salts glucose agar M9 medium. There was no detectable leakage loss of 260–280 nm‐absorbing materials. This was also confirmed by assay of the cellular RNA material components. Loss of alkaline phosphatase activity was observed in the stressed cells.

The intensity of induced cellular damage as measured by lysozyme sensitivity was greatest in the cells exposed to the complete TSS, followed by those stressed in 1% succinate at 5°C, then 5 ppm chlorine at 5°C and the singular chill shock stress at 5°C, respectively. The magnitudes of cellular damage, however, were suggestive of synergistic interactions among the component stress factors of the TSS.

The findings obtained indicate impairment of the structural integrity and functional capabilities of the permeability barriers and the inactivation of certain periplasmic enzymes. The resultant cumulative cellular damage from the TSS exposure may therefore enhance greater sensitivity of treated cells to subsequent stress factors.
The effect of pressure and temperature on sulphate‐reducing bacteria and the action of biocides in oilfield water injection systems
Authors: Stott J. F. D. , Herbert B. N.
Published: March 2008

The effects of elevated pressures and temperatures on the growth, morphology and metabolic activity of sulphate‐reducing bacteria, isolated from the North Sea, are described. Pressure/temperature profiles, growth curves and sulphate reduction rates are presented for several isolates. The maximum pressure and temperature that supported growth were 65 000 KPa and 45°C respectively. The results are discussed in connection with water injection into oil‐bearing reservoirs where there is a concern that generation of hydrogen sulphide by sulphate‐reducing bacteria may lead to increased hydrogen sulphide levels (souring) in oil and gas, and to corrosion problems in production facilities. The bacteriostatic effects of a number of commercial biocides were enhanced at elevated hydrostatic pressures and temperatures.
Occurrence of megaplasmids in halobacteria
Authors: Gutiérrez M. C. , García M. T. , Ventosa A. , Nieto J. J. , Ruiz‐Berraquero F.
Published: March 2008

Sixty‐five halobacteria, including culture collection and freshly isolated strains from widely differing geographical areas, were examined for the presence of high molecular weight plasmids by agarose gel electrophoresis. Seventy‐five per cent of all the strains were shown to harbour at least one plasmid. In the majority of strains three or four megaplasmids were detected. Approximate molecular weights of the plasmids were in the range < 100 to 300 megadaltons (Mdal). In most culture collection strains, two or three plasmids were demonstrated, except in two in which no plasmid was detected, and in two Haloarcula strains which were found to contain five and eight plasmids; four and six of the latter were more than 100 Mdal. No relationship between the plasmid profile of each strain and its taxonomic assignation nor its isolation source was found. Evidence is presented for the first time on the occurrence of megaplasmids in halobacteria.
Kinetics of the tuberculocidal response by alkaline glutaraldehyde in solution and on an inert surface
Authors: Collins F. M.
Published: March 2008

Single cell suspensions of BCG and Mycobacterium tuberculosis were exposed to 2% alkaline glutaraldehyde solution (pH 8·0) and the rate of kill measured at intervals up to 30 min. Residual glutaraldehyde was neutralized with freshly prepared 1% sodium bisulphite. The rate of kill was directly proportional to the temperature and independent of the inoculum size whether the organism was tested in suspension or attached to an inert surface. Glutaraldehyde was slightly more bactericidal for the virulent M. tuberculosis than for the attenuated BCG. A substantial proportion of the mycobacterial population on an inert surface floated off during its exposure to the glutaraldehyde solution but the ‘floaters’were killed at an equivalent rate to the attached bacilli. Complete sterility of a standardized suspension of M. tuberculosis could not be achieved within the 10 min period specified by the tuberculocidal assay, although it was usually attained within 20 min.
Diseased leaf lyophilization: a method for long‐term prevention of loss of virulence in phytopathogenic bacteria
Authors: Bashan Y. , Okon Y.
Published: March 2008

A technique for long‐term preservation of phytopathogenic bacteria is described. It is based on selective multiplication of the bacterial pathogen in host tissue, disinfection of leaf surfaces to reduce contamination, lyophilization of leaves, and storage under dry conditions at ‐ 80°C. With this technique, the pathogenicity of large numbers of the pathogens Pseudomonas syringae pv. tomato and Xanthomonas campestris pv. vesicatoria was maintained for 4 years.
Factors contributing to the seasonal variation of Bacillus spp. in pasteurized dairy products
Authors: Phillips J. D. , Griffiths M. W.
Published: March 2008

The seasonal variation in the spoilage of pasteurized products, especially double cream, by spore‐forming bacteria was due to a number of factors. By far the most important was the seasonal variation in the types of organisms isolated from raw milks. Psychrotrophic spore‐formers predominated in the summer‐autumn months and these strains were able to germinate rapidly and grow in refrigerated dairy products. There was evidence that the concentration of one or more factors which promoted germination of psychrotrophic strains of Bacillus spp. in milk was higher during the summer than in the winter. This again may contribute to seasonal differences in spoilage by spore‐forming bacteria. Post‐heat treatment contamination by spores of Bacillus spp. may also be more prevalent in the summer‐autumn period and evidence was obtained that spores associated with post‐pasteurization contamination could germinate and grow more rapidly than those introduced into the product from the raw material. Thus, the increased spoilage of pasteurized products by Bacillus spp. observed in the June to October period may be due to a combination of factors. The relative contribution that each makes is not easily resolved.
Numerical taxonomy of Bacillus isolated from orally administered drugs
Authors: Gil M. C. , Rosa M. C. DE LA , Mosso M. A. , Arribas M. L. Garcia
Published: March 2008

Numerical taxonomy procedures were used to study 118 strains of Bacillus isolated from non‐sterile drugs prepared for oral administration. Similarities between pairs of strains were calculated by the simple matching coefficient of Sokal and Michener (SSM). Each strain was tested for 60 unit characters and three clusters were defined. The strains in each cluster presented a similarity level of at least 60%. Cluster A comprised the strains identified as Bacillus cereus (SSM= 93·13%), cluster B contained three subgroups corresponding to the species B. pumilus, B. subtilis and B. licheniformis (SSM= 84·35%) and cluster C also included three subgroups that belonged to the species B. firmus, B. lentus and B. badius (SSM= 80·14%). The most discriminating tests were selected to differentiate the clusters from the subgroups. The feature with the highest discriminating power between clusters A and B was the lack of acid production from arabinose and mannitol. The Voges‐Proskauer, methyl red tests and sensitivity to polymyxin B clearly distinguished cluster A from C. The Voges‐Proskauer test and acid production from arabinose were the best to differentiate between B and C. Bacillus pumilus and B. subtilis differed in starch hydrolysis and B. licheniformis in growing anaerobically. To discriminate B. firmus from B. lentus the most important tests were the acid production from glucose and sucrose; intermediate strains were found. Bacillus badius was differentiated from B. firmus by 10 tests, and from B. lentus by the production of urease.
Reversal of the surface effects of chlorhexidine diacetate on cells of Providencia stuartii
Authors: Ismaeel N. , Furr J. R. , Russell A. D.
Published: March 2008

Chlorhexidine diacetate (CHA) increased the hydrophobicity of the cell surface of cells of three strains of Providencia stuartii. Removal of at least some of the CHA from the cells by washing them with an appropriate antidote partially reversed the hydrophobicity‐increasing action of the biguanide. The effects of other treatments on cell surface hydrophobicity were examined with these strains and, for comparison, with two strains each of Escherichia coli and Pseudomonas aeruginosa: ethyl‐enediamine tetraacetic acid affected all strains, although not to the same extent, whereas thermal injury (55°C) produced marked changes only with the two E. coli strains.
Collection of airborne micro‐organisms on Nuclepore filters, estimation and analysis—CAMNEA method
Authors: Palmgren U. , Ström G. , Blomquist G. , Malmberg P.
Published: March 2008

The total number of airborne micro‐organisms collected on Nuclepore filters was determined by acridine orange staining and epifluorescence microscopy. The viable fraction of the total numbers varied significantly when actinomycete and fungal spores from different environments were stored on the filter surface for 1 week, although the microflora composition was not altered. A high correlation between viable and total counts was noted in environments where the airborne flora was dominated by fungal spores, while a low correlation was found for airborne bacteria. Peak values of the total counts registered in some work environments varied between 107 and 1011 micro‐organisms/m3. Size analysis showed a dominating fraction of respirable micro‐organisms (aerodynamical diameter < 5 μm). The investigation shows that it is of the utmost importance to combine viable counts with total count enumeration in the study of exposure to micro‐organisms in work‐related situations.
Submicroscopical changes in Klebsiella pneumoniae cells treated with concentrated sucrose and polyethylene glycol 400 solutions
Authors: Bozzini J. P. , Kohn Elisa S. , Joseph Arabella , Herszage L. , Chirife J.
Published: March 2008

This study reports the extent and character of plasmolysis and other morphological changes as shown by electron microscopy in a strain of Klebsiella pneumoniae and with sucrose or polyethylene glycol 400 (PEG‐400) as the plasmolysing agent at a water activity of 0.935.

Both solutes produced severe plasmolysis in K. pneumoniae cells; PEG‐400 also caused some cell wall collapse and fingerlike extrusions to emerge from the bacterial cell.
Factors affecting the measurement of antibiotic resistance in bacteria isolated from lake water
Authors: Jones J. G. , Gardener S. , Simon B. M. , Pickup R. W.
Published: March 2008

It is more difficult to obtain a reliable assessment of antibiotic resistance in populations of aquatic bacteria than in those populations which are well characterized (e.g. bacteria of medical and veterinary significance). Factors which influence the results include the bacterial taxa involved, their site of origin and the methods and media used to isolate and subculture the bacteria, and to perform the sensitivity tests. Examples of these effects are provided. The resistance profiles obtained with populations of aquatic pseudomonads depend on the species composition of the population. Resistance patterns in aquatic bacteria varied with the site from which they were isolated; a higher incidence of resistance was recorded along shorelines and in sheltered bays than in the open water. The inclusion of antibiotics in the media employed for primary isolation increased the number of individual and multiple resistances recorded. A similar effect was observed with increased inoculum size in the sensitivity disc method but this could be reversed by raising the incubation temperature. The medium used to conduct the test also affected the results and many aquatic bacteria failed to grow on media such as Iso‐Sensitest Agar. It is recommended that the sensitivity disc method is adopted for aquatic bacteria because it permits interpretation of a wider range of response. Comparison of the incidence of antibiotic resistance in different habitats will remain meaningless, however, until comprehensive methods for the identification of bacteria are developed and the techniques used for sensitivity testing are standardized.
A note on the effect of the lactoperoxidase systems on salmonellas in vitro and in vivo
Authors: Wray C. , McLaren I.
Published: March 2008

The lactoperoxidase system (LPS), a natural bactericidal system in milk, was investigated for its activity against salmonellas in vivo and in vitro. In acidified raw milk, in which the LPS was supplemented with an exogenous supply of H2O2, the numbers of salmonellas decreased rapidly. Different salmonella serotypes were affected to the same extent; rough strains, however, were more susceptible than smooth strains. When calves were fed on fresh milk, containing the LPS, and challenged with Salmonella typhimurium in doses of either 109 or 1010, the clinical findings and salmonella excretion patterns were similar to those of control calves fed on heated milk. It was concluded that further studies, perhaps in the field, are necessary to evaluate LPS as a possible non‐antibiotic system to control salmonellosis.
Water relations of solute accumulation in Pseudomonas fluorescens
Authors: Prior B. A. , Kenyon C. P. , van der Veen Michelle , Mildenhall J. P.
Published: March 2008

When Pseudomonas fluorescens was grown in a glucose salts medium adjusted with NaCl to a water activity (aw) value of 0.980, the intracellular glutamic acid concentration increased 23‐fold and comprised 90% of the total amino acid pool. This increase was not observed when the aw of the medium was reduced to 0.980 with sorbitol. Sorbitol was taken up rapidly over a 30 min period and accumulated intracellularly to a level approximately two‐fold greater than the concentration in the growth medium. In continuous culture, the specific rate of glutamic acid production and glucose uptake was greater at 0.980 (NaCl) than at 0.997 aw. The maintenance coefficients for glucose uptake were similar at both aw values but were 2.4‐fold greater for glutamic acid production at 0.980 (NaCl) than at 0.997 aw.
Degradations of 4‐cholesten‐3‐one and 1,4‐androstadiene‐3,17‐dione by cholesterol‐degrading bacteria
Authors: Watanabe K. , Aihara H. , Tachi N. , Nakamura R.
Published: March 2008

Degradations of 4‐cholesten‐3‐one and 1,4‐androstadiene‐3,17‐dione, which are intermediates of microbial conversion of cholesterol, by cholesterol‐degrading bacteria (12 strains of the genus Rhodococcus isolated from food of animal origin and 12 culture collection strains) were examined. All strains had the ability to degrade 4‐cholesten‐3‐one without necessarily being able to degrade cholesterol. On the other hand, the bacteria were divided into three groups with little or no (0–10%), intermediate (10–70%) and high (70–100%) degradation abilities for 1,4‐androstadiene‐3,17‐dione.