Showing papers in "Journal of Applied Microbiology in 1986"

Collection of airborne micro-organisms on Nuclepore filters, estimation and analysis--CAMNEA method

Abstract: 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 10(7) and 10(11) micro-organisms/m3. Size analysis showed a dominating fraction of respirable micro-organisms (aerodynamical diameter less than 5 micron). 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.

Starch utilization by the human large intestinal microflora

Abstract: High levels (2-565 units/g) of amylase activity were observed in human faeces. Over 92% of amylase activity in faeces obtained from healthy persons was extracellular, whereas only about 9% of activity was associated with particulate material and washed cells. Bacterial cell-bound amylases were considerably more efficient in breaking down starch, however, than were the soluble enzymes which occurred in cell-free faecal supernatant fluids. Cell population densities of anaerobic starch-hydrolysing bacteria in the stools of ten persons ranged from 1.1 X 10(10) to 3.3 X 10(12)/g of faeces. Identification of 120 starch-hydrolysing colonies isolated from the stools of six subjects showed that the predominant amylolytic bacteria belonged to the genera Bifidobacterium, Bacteroides, Fusobacterium and Butyrivibrio. Mixed populations of gut bacteria rapidly fermented starch with the production of volatile fatty acids and organic acids. Lactate was observed to be a major, though transient intermediate during starch fermentation by these cultures. Approximately 60% of starch utilized was converted to volatile fatty acids, which in the human colon would be potentially available for absorption.

Bacteriophages and indicator bacteria in human and animal faeces

Abstract: In an attempt to explain the presence of F-specific (RNA) bacteriophages in waste-water, faecal material from humans and a variety of animals was examined. The phages were detected in appreciable numbers only in faeces from pigs, broiler chickens, sheep and calves but not from dogs, cows, horses and humans. Parallel examinations for somatic coliphages, thermotolerant coliforms, faecal streptococci and spores of sulphite-reducing clostridia revealed the consistent presence of these organisms in all types of samples, albeit in variable numbers. The number of F-specific bacteriophages was related to the total number of somatic coliphages, but phage counts were unrelated to bacterial counts. F-specific RNA phages were grouped by serotyping and all animal isolates were found to belong to either group I (MS2 subtype) or IV (four different subtypes). Among the group IV isolates, most belonged to well-known subtypes SP (24 isolates) or FI (18 isolates) but five isolates were related to phage ID2 and one isolate was a new subtype. In contrast with animal isolates, 19 isolates from hospital wastewater belonged to serogroups II or III.

Elevation of the heat resistance of Salmonella typhimurium by sublethal heat shock

Abstract: The survival of Salmonella typhimurium after a standard heat challenge at 55 degrees C for 25 min increased by several orders of magnitude when cells grown at 37 degrees C were pre-incubated at 42 degrees, 45 degrees or 48 degrees C before heating at the higher temperature Heat resistance increased rapidly after the temperature shift, reaching near maximum levels within 30 min Elevated heat resistance persisted for at least 10 h Pre-incubation of cells at 48 degrees C for 30 min increased their resistance to subsequent heating at 50 degrees, 52 degrees, 55 degrees, 57 degrees or 59 degrees C Survival curves of resistant cells were curvilinear Estimated times for a '7D' inactivation increased by 26- to 20-fold compared with cells not pre-incubated before heat challenge

Bacterial inoculants as silage additives

Abstract: Caracteristiques de la fermentation dans les ensilages. Les bacteries lactiques dans les ensilages (physiologie, presence de bacteries lactiques dans le vegetal ensile, developpement des bacteries lactiques dans les ensilages). Proprietes requises pour les bacteries utilisees comme inoculum. Selection des bacteries inoculantes. Influence du niveau d'inoculation et de la methode d'application. Influence de la composition de l'inoculum. Influence de la matiere seche et des constituants hydrosolubles de l'ensilage. Biodeterioration aerobie des ensilages inocules. Qualite nutritionnelle de l'ensilage. Ensemencement avec d'autres microorganismes que les bacteries lactiques. Conclusions et perspectives

Degradation of isolated grass mesophyll, epidermis and fibre cell walls in the rumen and by cellulolytic rumen bacteria in axenic culture

Abstract: The degradation of cell walls of mesophyll, epidermis and fibre cells isolated from leaves of perennial and Italian ryegrass within the sheep rumen or by selected strains of rumen bacteria in vitro, was followed by estimation of dry matter loss, or loss of neutral sugar residues. Primary cell walls (mesophyll and epidermis) were fully degraded within 12 h in the rumen, while the more heavily lignified fibre cell walls showed only a 40% loss of dry matter over the same period. Neutral sugar residues were lost at a common rate from walls of all three cell types. Incubation of cell walls with cellulolytic bacteria showed that the extent to which cell walls were attacked was constantly ordered (epidermis > mesophyll > fibre). The rate of degradation of cell walls was less in axenic culture than within the rumen. Greatest weight losses were produced by Ruminococcus albus, followed by Bacteroides succinogenes, with Ruminococcus flavefaciens effecting the least change, regardless of the nature of the cell wall provided as a substrate. Xylose was more readily lost from primary cell walls than glucose during the early stages of attack, but both were lost at a common rate from fibre cell walls. Dry matter losses produced by the hemicellulolytic strain, Bacteroides ruminocola, were limited even after extended incubation. Electron microscopy indicated that R. albus was less commonly attached to cell walls than were the other cellulolytic strains, although evidence of capsular material was present. Bacteroides succinogenes was seen with an extensive capsule which enveloped clusters of cells, forming micro-colonies in association with the plant cell wall. Vesicle-like structures, commonly associated with the cellulolytic bacteria R. albus and B. succinogenes, were found on comparatively few occasions in this study.

Inactivation of Bacillus spores by gaseous ozone

Abstract: The sporicidal activity of ozone in the gas phase was investigated. Spores of six strains of Bacillus species deposited on filter paper or glass fibre filter were conditioned at different relative humidities (r.h.), and then exposed to ozone ranging in concentration from 0.5 to 3.0 mg/l at different r.h. There was a lag phase in the initial stage of exposure followed by an exponential decrease in the number of survivors with time, although no lag phase was observed with one strain. Inactivation rates increased with increasing exposure r.h. while no significant inactivation was attained at a r.h. of 50% or below. The conditioning r.h. influenced the duration of the lag phase. The D-values (decimal reduction time) in the logarithmic phase varied roughly in inverse proportion to the ozone concentration.

Antibiotic resistant bacteria in Windermere and two remote upland tarns in the English Lake District

Abstract: The incidence of antibiotic resistance was determined in over 2000 bacteria which were divided into the following groups: faecal streptococci, coliforms (excluding Escherichia coli), E. coli, Pseudomonas spp. and aquatic bacteria (i.e. bacteria predominant in the lake water which were excluded from the previous four categories). The isolates were obtained from the water of Windermere (English Lake District) and from a sewage effluent which entered the lake. With the exception of the faecal streptococci, the incidence of antibiotic resistance was higher in the bacteria isolated from the lake water than in those from the effluent, and ranked according to groups Pseudomonas spp. > E. coli > aquatic bacteria > coliforms > faecal streptococci. The highest incidence of multiple resistance was found among the pseudomonads. When corrected for the relative size of each population the pool of antibiotic resistance in the aquatic bacteria was by far the largest. The incidence of antibiotic resistance in aquatic bacteria isolated from Windermere was, however, lower than in those isolated from two remote upland tarns. This finding may have been due to differences in the species composition of the three sites except that the same results were obtained when only fluorescent pseudomonads were tested. The upland tarns were not totally isolated from man and other animals but did not receive any sewage or other effluents and therefore the results were surprising. Possible explanations include a lack of susceptibility in aquatic bacteria and increased resistance associated with growth in nutrient poor environments.

Micro-organisms associated with African locust bean (Parkia filicoidea Welw) fermentation for ‘dawadawa’ production

Abstract: Micro-organisms associated with the fermentation of ‘dawadawa’, a traditionally prepared food condiment, were isolated and identified. Three species of bacteria (Bacillus subtilis, Leuconostoc mesenteroides and L. dextranicus) were the predominant and most actively involved organisms. The other organisms did not appear to play any major role in the fermentation because they were present in relatively low numbers in the fermenting mash. The temperature and the pH increased sharply during the fermentation process.

Effect of chlorine dioxide on selected membrane functions of Escherichia coli

Abstract: The mode of action of chlorine dioxide on Escherichia coli was assessed by studying outer membrane permeability to macromolecules and potassium, and observing effects on respiration. The results indicate that gross cellular damage involving significant leakage of intracellular macromolecules does not occur. There was a substantial efflux of potassium, however, and respiration was inhibited even at sublethal doses. It was concluded that the inhibition of respiration, which could be due to the damage to the cell envelope, was not the primary lethal event. Observations of the efflux of K+ strongly implicate the loss of permeability control as the primary lethal event at the physiological level, with nonspecific oxidative damage to the outer membrane leading to the destruction of the trans-membrane ionic gradient.

Numerical classification of species of Vibrio and related genera.

Abstract: Data from 1091 strains of the family Vibrionaceae collected in five different studies have been merged into a single data matrix and analysed in a taxonomic study. A set of 142 characters was selected to compare these data. Seventy-nine characters were common to all studies, but data for the other 63 characters were incomplete. Cultures of 90 strains, examined in more than one of the original studies, were used to estimate test error and inter-study variability. The data from these replicate strains also allowed the problem of merging data from different studies to be assessed. Taxonomic resemblance was estimated on the basis of 111 characters using the SSM coefficient and UPGMA clustering. A taxonomic analysis based on 999 strains, which included most of the major species of the family Vibrionaceae, gave 59 clusters and 44 unclustered strains. A table of properties of these phenons was produced. The results showed that data obtained from studies carried out at different times and in different locations, but using standard techniques, could be combined and used to provide useful taxonomic information.

Bacterial sources of putrescine and cadaverine in chill stored vacuum-packaged beef

Abstract: Of the meat strains of streptobacteria, leuconostocs, Enterobacteriaceae and Brochothrix thermosphacta tested, only Hafnia alvei and Serratia liquefaciens showed diamine-producing potential during growth in pure culture on beef stored in vacuum packs at 1 degree C. Both organisms produced cadaverine at concentrations similar to those reported previously in naturally contaminated beef stored under the same conditions. Putrescine concentrations produced by the two organisms, however, were an order of magnitude lower. During the growth on beef of either H. alvei or S. liquefaciens in mixed culture with arginine-utilizing strains of streptobacteria, putrescine as well as cadaverine concentrations were similar to those detected in naturally contaminated samples.

Detection of cellulolytic fungi by using Congo red as an indicator: a comparative study with the dinitrosalicyclic acid reagent method

Abstract: Cellulolytic fungi can easily be screened within 2 d for the production of cellulolytic enzymes by staining with Congo red, or by measuring the amount of reducing sugar (glucose) produced with the dinitrosalicyclic acid reagent method. Endoglucanase activity is visible in carboxymethyl cellulose agar plates after staining with Congo red, and fixing with HCL or NaOH. This method is essentially based on the interaction of Congo red with intact β-(1-4)-D-glucans in carboxymethyl cellulose. Endoglucanase and exoglucanase activities of cellulases are quantitatively measured with the dinitrosalicyclic acid reagent method. The enzymatic activity detected with Congo red is compared with that obtained by the dinitrosalicyclic acid reagent method.

Bactericidal activity of alkaline glutaraldehyde solution against a number of atypical mycobacterial species

Abstract: The mycobactericidal activity of 2% alkaline glutaraldehyde solution was determined using standardized suspensions of 10 species of atypical mycobacteria and compared with that for virulent Mycobacterium tuberculosis. Suspensions of M. avium, M. intracellulare and M. gordonae were more resistant to disinfection by the glutaraldehyde than were virulent tubercle bacilli while M. kansasii, M. scrofulaceum and M. szulgae were somewhat more susceptible. Mycobacterium marinum, M. smegmatis and M. fortuitum were highly sensitive to the disinfectant action of the alkaline glutaraldehyde solution. This variation in sensitivity shown by apparently closely related strains of mycobacteria to this disinfectant has important practical implications.

Techniques for the optimum recovery of cold injured Campylobacter jejuni from milk or water

Abstract: When broth was inoculated with cells of Campylobacter jejuni that had been injured by chilling there was a fall in the viable population of up to 90%. It was greater at 43 degrees than 37 degrees C and in the presence of certain antibiotics and in some cases resulted in a surviving population that was below the minimum inoculum for subsequent growth. A technique of pre-enrichment in non-selective culture broth at 37 degrees C for 2 h before the addition of antibiotics and incubation at 43 degrees C was found to significantly reduce the fall in numbers and to improve the detection of C. jejuni in samples of raw milk and water.

Factors contributing to the seasonal variation of Bacillus spp. in pasteurized dairy products

Abstract: 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.

A comparative study of the rod and coccoid forms of Campylobacter jejuni ATCC 29428

Abstract: Coccoid forms in cultures of a strain of the enteric pathogen Campylobacter jejuni were investigated. A culture containing 100% coccoid forms was non-viable. Coccoid forms had a lesser content of cytoplasmic components and nucleic acids than rods of C. jejuni. During the conversion to coccoid forms nucleotides leaked from the cells. The results of treatments with ionic and non-ionic detergents, and lysozyme and ethylenediaminetetraacetic acid indicated a changed cell wall in coccoid forms compared with rods. Using rate-zonal centrifugation coccoid forms were found to be less dense than rods. The results of this study indicate that the coccoid form of C. jejuni ATCC 29428 is a degenerate cell form which is undergoing cellular degradation.

The metabolism of carbaryl by three bacterial isolates, Pseudomonas spp. (NCIB 12042 & 12043) and Rhodococcus sp. (NCIB 12038) from garden soil.

Abstract: At an alkaline pH and in aqueous solution, carbaryl hydrolyses to form 1-naphthol, methylamine and carbon dioxide, but it is much more stable at an acid pH. Two bacterial isolated from garden soil, Pseudomonas sp. (NCIB 12042) and Rhodococcus sp. (NCIB 12038), could grow on carbaryl as sole carbon and nitrogen source at pH 6.8 but failed to metabolize carbaryl rapidly. Both could use 1-naphthol as sole carbon source and NCIB 12042 metabolized 1-naphthol via salicylic acid which induced higher expression of enzymes in the pathway. Strain NCIB 12038 metabolized 1-naphthol via salicylic and gentisic acids. In contrast, Pseudomonas sp. (NCIB 12043) was selected in a soil perfusion column enrichment at pH 5.2 and metabolized carbaryl rapidly to 1-naphthol and methylamine. 1-Naphthol was metabolized via gentisic acid. Neither salicylate nor gentisate induced higher expression of enzymes for 1-naphthol catabolism in NCIB 12038 and NCIB 12043.

Evaluation of selective media for enumeration of yeasts during wine fermentation

Abstract: The growth of individual species of yeasts during wine fermentations was measured by plating wine samples on malt extract, ethanol sulphite and lysine agars. Colonies of Saccharomyces cerevisiae dominated on plates of malt extract agar and sometimes masked the presence of other non-Saccharomyces species. Lysine agar suppressed the growth of S. cerevisiae and enabled the enumeration of non-Saccharomyces species such as Kloeckera apiculata, Candida stellata and Saccharomycodes ludwigii. The growth of non-Saccharomyces yeasts on ethanol sulphite agar was variable.

Comparative study of different methods for detection and enumeration of Salmonella spp. in natural waters.

Abstract: Seven enrichment media (two proposed by the authors) for detecting salmonellas from polluted freshwater were compared. The Most Probable Number technique for enumeration of salmonellas in water samples was used, directly adding filtered water to buffered peptone water as the pre-enrichment medium. The results indicate that Rappaport-Vassiliadis/43 and Rappaport-Vassiliadis/43 supplemented with 10 micrograms of sodium novobiocin per ml are the best media for the recovery and enumeration of salmonellas from water samples.

DNA-DNA homology, physiological characteristics and distribution of lactic acid bacteria isolated from maize silage

Abstract: Lactic acid bacteria represent a dynamic bacterial group in maize silages. their establishment, variations and characterization have been studied by investigating 22 samples taken at different times during the ensilage process. After a preliminary screening based on physiological characteristics, 100 of 229 strains isolated were chosen for further taxonomic investigation. Twenty-nine strains of homo-fermentative lactobacilli were identified as Lactobacillus plantarum, L. casei and L. coryniformis subsp. coryniformis; 24 heterofermentative strains were allotted to the species L. buchneri, L. brevis, L. fermentum and Leuconostoc paramesenteroides; 22 coccal strains were assigned to Pediococcus pentosaceus and P. acidilactici and 25 coccal strains were identified as Enterococcus faecium, Streptococcus lactis and Strep. bovis. A few strains remained unidentified.

A probability matrix for the identification of species of Vibrio and related genera.

Abstract: A matrix for the probabilistic identification of species of Vibrio and related genera has been constructed using the data from 1091 strains collected throughout the world and classified. Thirty-eight phenons are included in the matrix, 31 of these represent previously identified species or biovars and seven represent phenons which could not be identified and may represent new species. The identification matrix incorporates 81 characters although a subset of 30 tests can be used to distinguish the 38 phenons from each other. The additional 51 tests were included to assist the identification of some strains for which the initial 30 tests were inadequate. No significant cluster overlap was found at the 5% level and the identification score for the Hypothetical Median Organism of each cluster exceeded 0.9999 in all cases.

Evaluation of a commercial β-glucuronidase test for the rapid and economical identification of Escherichia coli

Abstract: A commercial beta-glucuronidase (beta-GUR) test for the rapid and economical identification of Escherichia coli was evaluated. A total of 762 clinical strains and 228 environmental isolates were studied. More than 95% of the E. coli strains were found to be beta-GUR positive. Thirty-one clinical isolates of Shigella sonnei, 10 of Enterobacter cloacae, eight of Enterobacter aerogenes, nine of Citrobacter freundii and one of Salmonella enteritidis also gave positive results. The enzyme beta-GUR was also detected in two environmental strains of E. cloacae and one C. freundii. A comparative study between the beta-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 190 E. coli strains were correctly identified using this test. Discrepancies were found in 10 cases: nine E. coli were beta-GUR negative and one C. freundii was beta-GUR positive. Escherichia coli was the only species positive for both beta-GUR and indole tests. This procedure permits a rapid, easy, precise and inexpensive identification of E. coli. beta-GUR positive Enterobacter strains have not previously been described.

The effect of citric acid on growth of proteolytic strains of Clostridium botulinum

Abstract: In strictly anaerobic conditions in a culture medium adjusted to pH 5.2 with HCl and incubated at 30 degrees C, inocula containing less than 10 vegetative bacteria of Clostridium botulinum ZK3 (type A) multiplied to give greater than 10(8) bacteria per ml in 3 d. Growth from an inoculum of between 10 and 100 spores occurred after a delay of 10-20 weeks. Citric acid concentrations of 10-50 mmol/l at pH 5.2 inhibited growth from both vegetative bacteria and spore inocula, a concentration of 50 mmol/l increasing the number of vegetative bacteria or of spores required to produce growth by a factor of approximately 10(6). The citric acid also reduced the concentration of free Ca2+ in the medium. The inhibitory effect of citric acid on vegetative bacteria at pH 5.2 could be prevented by the addition of Ca2+ or Mg2+ and greatly reduced by Fe2+ and Mn2+. The addition of Ca2+, but not of the remaining divalent metal ions, restored the concentration of free Ca2+ in the medium to that in the citrate-free medium. The inhibitory effect of citric acid on growth from a spore inoculum was only partially prevented by Ca2+. Citric acid (50 mmol/l) did not inhibit growth of strain ZK3 at pH 6 despite the greater chelating activity of citrate at pH 6 than at pH 5.2. The effect of citric acid and Ca2+ at pH 5.2 on vegetative bacteria of strains VL1 (type A) and 2346 and B6 (proteolytic type B) was similar to that on strain ZK3.

Factors affecting the measurement of antibiotic resistance in bacteria isolated from lake water.

Abstract: 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.

Detection and enumeration of Listeria monocytogenes in a sewage treatment plant in Iraq.

Abstract: Listeria monocytogenes was isolated from a sewage treatment plant in Baghdad, Iraq, at all stages of treatment. The treatment processes did not yield a sewage sludge cake or a final discharge free of listerias. The agricultural practice of using such sewage products as fertilizers could become a route of spreading the organism in Iraq, particularly by infecting animals that consume vegetation in fields spread with such sewage. Dewatering of sewage reduced the number of L. monocytogenes but long periods of exposure to sun would be needed to obtain a 'safe' sewage sludge cake.

A rapid method for identifying and quantifying soft rot erwinias directly from plant material based on their temperature tolerances and sensitivity to erythromycin

Abstract: A method is described for identifying and quantifying three soft rot erwinias directly from plant tissue and from other sources that is particularly useful in epidemiological studies. Colonies of these bacteria form characteristic deep cavities on selective-diagnostic crystal violet pectate (CVP) medium. Bacteria from individual presumptive erwinia colonies on CVP plates spot inoculated on plates of CVP medium with or without erythromycin (35 μg/ml) added and incubated at 27, 33°5 and 37°C can be identified according to the pattern of cavity formation. Erwinia carotovora pv. atroseptica forms the characteristic cavities only at 27°C and E. carotovora pv. carotovora at 27 and 33.5°C but not at 37°C on CVP with or without erythromycin. Erwinia chrysanthemi forms cavities at all temperatures and can also be identified by failure to grow at 27°C on CVP with erythromycin. Similarly, erwinias in mixed populations can be quantified by dilution plating on CVP with or without erythromycin and incubating at the different temperatures. Using this method, ca 80% of 183 erwinia strains in a culture collection were correctly identified, the precision increasing to over 95% when recently isolated erwinia strains were examined.

Isolation and characterization of aerobic heterotrophic bacteria from natural spring waters in the Lanjaron area (Spain)

Abstract: Aerobic, heterotrophic bacteria were isolated from nine natural mineral water springs in the Lanjaron area of Spain over the period July 1980 to May 1981. The mineral waters contained few bacteria (mean counts 26-5275 cfu per 100 ml) and the bacterial flora of all nine springs was very similar. Most of the isolates were Gram-negative rods (90%), and among these Pseudomonas spp. and members of the Flavobacterium-Cytophaga-Flexibacter group were numerically dominant. Aeromonas-Vibrio and Enterobacteriaceae isolates were an important fraction of the total number, but isolates from remaining groups (Acinetobacter, Chromobacterium, Alcaligenes and Gram-positive organisms) constituted only a small proportion of the flora. The comparatively small number of species isolated, and the occurrence of no more than three or four different bacterial types in spring water of different chemical and physical composition is discussed.

The identification of Pseudomonas cepacia and its occurrence in clinical material.

Abstract: During the 19 year period ending December 1984, 4840 strains of Gram-negative non-fermentative bacteria were submitted to the National Collection of Type Cultures for identification. Of these, 195 strains (4.0% of the total) were identified as Pseudomonas cepacia which demonstrates both that the species is regularly encountered in clinical material in the UK and that several laboratories have experienced difficulty in identifying the organism. The sources from which the 195 strains were isolated are reported and also the characteristics by which the species may be recognized. The clinical significance of Ps. cepacia is reviewed, and the resistance of this species to disinfectants and antimicrobial agents commonly used to treat pseudomonas infections is discussed to underline the necessity for the precise identification of Ps. cepacia.

Seasonal distribution of facultatively enteropathogenic vibrios (Vibrio cholerae, Vibrio mimicus, Vibrio parahaemolyticus) in the freshwater of the Elbe River at Hamburg

Abstract: Between June 1981 and December 1982 the incidence of Vibrio cholerae, V. mimicus and V. parahaemolyticus was determined at two sampling sites on the Elbe River at Hamburg. A total of 183 strains was isolated from 147 water samples. Of these, 107 belonged to non-01 V. cholerae (ten strains producing a cholera-like enterotoxin); 33 were identified as V. mimicus, including two enterotoxin producers; 42 strains were Kanagawa-negative cultures of V. parahaemolyticus; and one was V. fluvialis. The highest incidence was observed from June to September with about 10(2) organisms/l. Halophilic vibrios, less than five organisms/l, were detectable during the period June/July to October. The vibrio incidence was not influenced by the numbers of aerobic heterotrophic bacteria, coliforms or faecal bacteria. In general water temperature correlated with the seasonal variation. Thus, a temperature rise over 10 degrees to 20 degrees C was followed by a distinct increase in vibrio numbers. Of 14 chemical parameters only chloride concentration might have had an influence on the seasonal variation. It is concluded that the three Vibrio species are indigenous organisms of the Elbe River.