Showing papers on "Agar plate published in 2000"

Biological control of Sclerotinia minor using a chitinolytic bacterium and actinomycetes

Abstract: Isolates of 85 bacteria and 94 streptomycete and 35 nonstreptomycete actinomycetes were obtained from a lettuce-growing field in Al-Ain, United Arab Emirates, on colloidal chitin agar, and screened for their ability to produce chitinase. Twenty-three bacteria and 38 streptomycete and 15 nonstreptomycete actinomycete isolates produced high levels of chitinase and were examined in vitro for their ability to suppress the growth of Sclerotinia minor, a pathogen causing basal drop disease of lettuce. The three most suppressive isolates were examined further for their production of β-1,3-glucanase and antifungal activity as well as their ability to colonize the roots and rhizosphere of lettuce in vitro and in planta. The three isolates, Serratia marcescens, Streptomyces viridodiasticus and Micromonospora carbonacea, significantly reduced the growth of S. minor in vitro, and produced high levels of chitinase and β-1,3-glucanase. Streptomyces viridodiasticus also produced antifungal metabolite(s) that significantly reduced the growth of the pathogen in vitro. When the pathogen was presented as the sole carbon source, all three isolates caused extensive hyphal plasmolysis and cell wall lysis. Serratia marcescens and St. viridodiasticus were competent to varying degrees in colonizing the roots of lettuce seedlings after 8 days on agar plates and the rhizosphere within 14 days in pots, with their competency being superior to that of M. carbonacea. All three isolates, individually or in combination, were antagonistic to S. minor and significantly reduced incidence of disease under controlled glasshouse conditions.

A simple method for extraction of fungal genomic DNA.

Abstract: We have developed a new, simple and effective method for extraction of fungal genomic DNA. The initial steps involved suspension of freeze-dried mycelium in buffer containing sodium dodecyl sulphate, detachment of DNA from polysaccharides by mild shearing, NaCl precipitation of polysaccharides and protein, chloroform extraction and ethanol precipitation. The ethanol precipitate was then subjected to a second round of mild shearing, NaCl precipitation, chloroform extraction and ethanol precipitation. The procedure required approximately 1 h to perform. The method yielded 8-32 microg of high molecular weight DNA per 30 mg of freeze-dried mycelium when tested on six fungal species: Aspergillus niger, A. flavus, Fusarium graminarum, Neotyphodium lolii, Penicillium citrinum and Rhizopus nigricanes. The DNA was digestible with EcoRI, HindIII, SalI and BamHI. For the slow-growing N. lolii, a modification of the method was developed that removed the agar residue from colonies grown on agar plates by centrifugation at 13 000 rev min(-1) in the presence of CsCl. The modified method yielded 1.5-2 microg of high molecular weight DNA per colony.

Antifungal susceptibility testing of dermatophytes: establishing a medium for inducing conidial growth and evaluation of susceptibility of clinical isolates.

Abstract: A standardized reference method for dermatophyte in vitro susceptibility testing is lacking. In a previous study, Norris et al. (H. A. Norris, B. E. Elewski, and M. A. Ghannoum, J. Am. Acad. Dermatol. 40(6, part 2):S9-S13) established the optimal medium and other growth variables. However, the earlier study did not address two issues: (i) selection of an optimal medium for conidial formation by dermatophytes and (ii) validation of the method with a large number of dermatophytes. The present study addresses these two points. To select which agar medium best supported conidial growth, representative isolates of dermatophytes were grown on different agars. Preliminary experiments showed that only oatmeal cereal agar supported the production of conidia by Trichophyton rubrum. We tested the abilities of 251 T. rubrum isolates to form conidia using three different cereal agars and potato dextrose agar. Overall, oatmeal cereal and rice agar media were comparable in their abilities to support T. rubrum conidial growth. Next, we used the oatmeal cereal agar for conidial formation along with the optimal conditions for dermatophyte susceptibility testing proposed by Norris et al. and determined the antifungal susceptibilities of 217 dermatophytes to fluconazole, griseofulvin, itraconazole, and terbinafine. Relative to the other agents tested, terbinafine possessed the highest antifungal activity against all of the dermatophytes. The mean +/- standard error of the mean MICs of fluconazole, itraconazole, terbinafine, and griseofulvin were 2.07 +/- 0.29, 0.13 +/- 0.01, 0.002 +/- 0.0003, and 0.71 +/- 0.05 microgram/ml, respectively. This study is the first step in the identification of optimal conditions that could be used for the standardization of the antifungal susceptibility testing method for dermatophytes. Inter- and intralaboratory agreement as well as clinical correlations need to be established.

Distribution and Exudation of Allelochemicals in Wheat Triticum aestivum

Abstract: Wheat allelopathy has potential for weed suppression. Allelochemicals were identified in wheat seedlings, and they were exuded from seedlings into agar growth medium. p-Hydroxybenzoic, trans-p-coumaric, cis-p-coumaric, syringic, vanillic, trans-ferulic, and cis-ferulic acids and 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) were identified in both the shoots and roots of 17-day-old wheat seedlings and their associated agar growth medium. Wheat accessions with previously identified allelopathic activity tended to contain higher levels of allelochemicals than poorly allelopathic ones. The allelopathic compounds present in the shoots generally also were identified in the roots and in the agar medium. Allelochemicals were distributed differentially in wheat, with roots normally containing higher levels of allelochemicals than the shoots. When the eight allelochemicals were grouped into benzoic acid and cinnamic acid derivatives, DIMBOA, total coumaric, and total ferulic acids, the amount of each group of allelochemicals was correlated between the roots and the shoots. Most of the allelochemicals identified in the shoots and roots could be exuded by the living roots of wheat seedling into the agar growth medium. However, the amounts of allelochemicals in the agar growth medium were not proportional to those in the roots. Results suggest that wheat plants may retain allelochemicals once synthesized. The presence of allelochemicals in the agar growth medium demonstrated that wheat seedlings were able to synthesize and to exude phytotoxic compounds through their root system that could inhibit the root growth of annual ryegrass.

Relationship among Mutans Streptococci, "Low-pH" Bacteria, and lodophilic Polysaccharide-producing Bacteria in Dental Plaque and Early Enamel Caries in Humans

Abstract: Multiple interactions occur among major determinants of dental caries We have studied the bacterial flora and pH-lowering capacity of the same dental plaques in relation to caries The findings on the plaque flora are reported here The buccal surfaces of upper teeth in each subject were selected for study A low-caries group had no "white spot" caries (ws) in the selected dentition area; a higher-caries group averaged 41 ws in this area The latter group was divided into subjects with 2, 3, or 4 ws and subjects with 5, 6, or 7 ws Enumerated organisms in plaque samples (sound and ws sites) from all subjects were: (1) mutans streptococci (MS) on mitis-salivarius-bacitracin and mitis-salivarius agar; (2) non-mutans streptococci (non-MS) on mitis-salivarius agar; (3) organisms that were categorized according to their minimum pH in sugar broth, ie, the predominant undifferentiated total flora on blood agar or the predominant non-MS flora on mitis-salivarius agar; and (4) iodophilic polysaccharide-storing

Evaluation of CHROMagar Staph. aureus, a New Chromogenic Medium, for Isolation and Presumptive Identification of Staphylococcus aureus from Human Clinical Specimens

Abstract: CHROMagar Staph. aureus (CSA) is a new chromogenic medium for presumptive identification of Staphylococcus aureus as mauve colonies after 24 h of incubation. We conducted a preliminary study with 100 S. aureus and 45 coagulase-negative Staphylococcus (CoNS) stock isolates plated on CSA. All S. aureus isolates yielded mauve colonies after 24 h of incubation at 37 degrees C, while CoNS isolates grew as blue, white, or beige colonies. Culture on CSA was then prospectively compared to a conventional laboratory method, i.e. , culture on 5% horse blood agar (HBA), catalase test, and latex agglutination test (HBA-catalase-latex), for isolation and presumptive identification of S. aureus from 2,000 consecutive clinical samples. Among the 310 S. aureus isolates recovered by at least one of the two methods, 296 grew as typical mauve colonies on CSA, while only 254 yielded catalase-positive, latex-positive colonies on HBA. The sensitivity of CSA was significantly higher than that of the conventional method (95.5 and 81.9%, respectively; P < 0.001) and allowed the recovery of important clinical isolates that were undetected on blood agar. The specificities of the two methods were not significantly different, although that of CSA was slightly higher (99.4% versus 98.9% for HBA-catalase-latex; P = 0. 08). On the basis of its excellent sensitivity and specificity, ease of identification of positive colonies, and absence of complementary testing, CSA can be recommended as a routine plating medium for presumptive identification of S. aureus in clinical specimens.

Genetic diversity of total, active and culturable marine bacteria in coastal seawater

Abstract: The genetic diversity of marine bacteria from coastal Mediterranean water was ana- lyzed using denaturing gradient gel electrophoresis (DGGE) and comparative sequence analysis of PCR-amplified 16S rRNA genes. The diversity of the whole bacterial assemblage was compared to the diversity of the fraction of actively respiring bacterial cells and of culturable bacteria. Culturable bacteria were isolated on agar plates using 4 different culture media, as well as in filtered autoclaved seawater following dilution to extinction. The cell fractions exhibited varied genetic diversity. High similarity between DGGE patterns obtained from the whole bacterial assemblage and those obtained from the active cell fraction (representing only 3% of total cells) indicated the simultaneous presence of both active and inactive cells within populations corresponding to numerous bacterial phylotypes defined as DGGE bands. Furthermore, an important source of genetic diversity corresponding to viable organisms, detected by culturability on agar media and in dilution culture with unamended seawater, was not detectable by DGGE patterns obtained from total cells. Most of the strains isolated by dilution cultures were different from those isolated on solid agar media. These results suggest that studies on the structure of complex marine bacterial communities do not necessarily reflect the phys- iological heterogeneity of ecologically important populations and may ignore populations present at low relative abundance that can play a key ecological role.

Antimicrobial activity of human cervical mucus

Abstract: The antibacterial activity of human cervical mucus (CM) was examined on standardized microbial colonized agar plates (agar diffusion test). In parallel, the lysozyme content of CM was determined by means of a turbidimetric test system in aliquots of the same CM specimens. Suspensions of living lyophilized Micrococcus lysedeikticus were used as bacterial substrate. Testing was performed in a total of 133 CM samples, obtained at mid-cycle from sexually active women from unselected infertile couples with a median age of 30 (range 21-42) years. All mucus specimens showed considerable antibacterial activity with clearly visible circular inhibition zones around the CM-filled holes in the colonized agar plates. Related to the effect of hen's egg white (HEW)-lysozyme on the same plates, the median activity of the CM specimens in the agar diffusion test was equivalent to 33.0 (range 6.4-391.4) microg/ml HEW-lysozyme. However, there was a wide inter-individual range of antibacterial effects of cervical secretions. The cervical index did not significantly influence the outcome of either test. The pH of the endocervical CM also was not correlated with the antibacterial effect. Sexual activity leading to the presence of spermatozoa in CM considerably increased its antibacterial effect. The activity was markedly higher in samples obtained within hours after intercourse compared with those taken after sexual abstinence of >/=5 days (P < 0.05). In microbially colonized CM specimens compared to sterile CM, all obtained under hormonally standardized conditions, the antibacterial activity in the agar plate test was significantly lower (P < 0.05). The results of this pilot study demonstrate the considerable antibacterial activity of human CM.

Pulsed electric field inactivation of diarrhoeagenic Bacillus cereus through irreversible electroporation

Abstract: The physical effects of high-intensity pulsed electric fields (PEF) on the inactivation of diarrhoeagenic Bacillus cereus cells suspended in 01% peptone water were examined by transmission electron microscopy (TEM) The levels of PEF-induced microbial cell death were determined by enumeration on tryptone soy yeast extract agar and Bacillus cereus-selective agar plates Following exposure to lethal levels of PEF, TEM investigation revealed irreversible cell membrane rupture at a number of locations, with the apparent leakage of intracellular contents This study provides a clearer understanding of the mechanism of PEF-induced cellular damage, information that is essential for the further optimization of this emerging food-processing technology

Effects of light, growth media, and seedling orientation on bioassays of alfalfa autotoxicity.

Abstract: Most assessments of allelopathy involve bioassays. Our objective was to improve the sensitivity of an alfalfa (Medicago sativa L.) seedling bioassay for evaluating genetic tolerance to autotoxic leaf extracts. In a petri dish assay on imbibed seed, light inhibited hypocotyl elongation of controls and increased root elongation. Root growth was sensitive to the autotoxin in both light and darkness. An agar medium gave better root growth of controls and lower standard errors than did filter paper when petri dishes were placed on edge to encourage downward root growth or were placed flat where roots grew laterally. Hypocotyl growth was not very sensitive to the autotoxic chemical(s) on either agar or paper medium when the plate was flat, because the hypocotyl arched upward to escape contact with the extract. Hypocotyl growth was sensitive in a rolled paper towel treatment held vertically because the hypocotyl remained in continuous contact with the extract. On agar plates placed flat, 50% inhibition of root length occurred at an extract concentration that was about 8% of that needed for 50% inhibition of germination at 36 and 48 h. Root growth was stimulated up to 15% above controls at very low concentrations of leaf extract. Root length at 120 h was the best indicator of autotoxic effects of alfalfa leaf extracts. We evaluated 17 germplasms and three cultivars of alfalfa for root growth response to the autotoxic chemical and found a twofold range (P < 0.05) in tolerance.

Efficient rooting for establishment of papaya plantlets by micropropagation

Abstract: A low cost micropropagation protocol to produce high quality root systems which are easy and economical to acclimatize is essential for large-scale micropropagation of papaya (Carica papaya L.). In this study, individual shoots (>0.5 cm) with 2∼3 leaves from in vitro papaya multiple shoots were cultured on MS agar medium containing 2.5 μM IBA under dark conditions for 1 week for root induction. They were then transferred to agar or vermiculite media, containing half strength MS medium, under aerated or non-aerated conditions, for root development. Rooting percentage of shoots cultured for 2 weeks in aerated vermiculite was 94.5%, compared with 90.0% in non-aerated vermiculite, 71.1% in aerated agar, and 62.2% in non-aerated agar. Shoots with roots were acclimated in vermiculite under 100% RH for 1 week and then under ambient conditions for 2 weeks in a temperature-controlled growth chamber (28 °C). The survival rates of the plantlets were 94.5% from aerated vermiculite, 87.8% from non-aerated vermiculite, 42.2% from aerated agar, and 35.6% from non-aerated agar. Thus, root induction in low-concentration IBA agar medium followed by root development in vermiculite containing half strength MS medium under aerated conditions results in efficient rooting of in vitro papaya shoots.

New agar medium for testing susceptibility of Mycobacterium tuberculosis to pyrazinamide.

Abstract: A new agar medium to perform pyrazinamide (PZA) susceptibility testing with Mycobacterium tuberculosis has been developed. This medium has an acidic pH of 6.0 instead of the usual for agar media, pH 6.8, to provide optimal conditions for PZA activity, and it also differs from conventional Middlebrook 7H10/7H11 agar in that animal serum (fetal or calf bovine or fetal equine serum) is used instead of oleic acid-albumin-dextrose-catalase to support good growth of M. tuberculosis at the low pH of 6.0. A critical concentration of 900 or 1,200 μg of PZA/ml in this medium made it possible to differentiate between PZA-susceptible and PZA-resistant clinical isolates. This agar medium has the following advantages compared to a liquid medium: it allows determination of the actual proportion of PZA-resistant bacteria in the isolate and it is simple and inexpensive. In addition, it has the potential of being used for a direct susceptibility test with PZA, but this approach will require further confirmation. Further studies to develop critical concentrations of other drugs for this low-pH medium, as well as to investigate the possibility of cultivation in regular (non-CO2) incubators, are in progress.

Use of prawn blood agar hemolysis to screen for bacteria pathogenic to cultured tiger prawns Penaeus monodon.

Abstract: A newly developed prawn blood agar consisting of 1 ml of tiger prawn hemolymph in medium containing 200 ppm Rose Bengal was used to determine the hemolytic activity of 35 isolates of bacteria obtained from cultured tiger prawns Penaeus monodon and their rearing water. For comparison, the hemolytic activity of these isolates was also determined in sheep blood agar. Nine isolates (25.7% of total) showed different hemolytic reactions on prawn blood agar and sheep blood agar. From the 35 isolates, 8 with various hemolytic characteristics were selected and the relationship between the type of hemolytic activity and pathogenicity was determined and compared. Four isolates that showed hemolytic activity in prawn blood agar caused high mortality to cultured tiger prawns. By contrast, a significantly lower mortality rate was observed for tiger prawns injected with 4 isolates that did not exhibit hemolytic activity on prawn blood agar. Results further showed that mortality did not correlate with hemolytic activity determined using sheep blood agar. Prawn blood agar containing P. monodon hemocytes was faster and more accurate for determining prawn hemolytic activity of bacterial isolates.

Pig and goat blood as substitutes for sheep blood in blood-supplemented agar media.

Abstract: In many developing countries sheep and horse blood, the recommended blood supplements in bacteriological media, are not readily available, whereas pig and goat blood are. Therefore, this study examined the use of pig and goat blood as potential substitutes for sheep blood in blood-supplemented bacteriologic media commonly used in clinical microbiology laboratories. In general, the growth characteristics and colony morphologies of a wide range of aerobic and anaerobic bacteria and Candida albicans were similar on media containing pig, goat, and sheep blood, although differences were found. Enterococcus sp. uniformly produced alpha-hemolysis when incubated in CO(2), but in anaerobic conditions the hemolysis varied. In contrast, beta-hemolytic streptococci produced identical hemolytic reactions on all three media. Synergistic hemolysis was not observed on pig blood agar in the CAMP test nor on goat blood agar in the reverse CAMP test. The preparation of chocolate agar (heated) with pig blood required heating to a higher temperature than with sheep or goat blood to yield suitable growth of Haemophilus species. In general, we conclude that pig and goat blood are suitable alternatives to sheep blood for use in bacteriological media in settings where sheep and horse blood are not readily available.

Haemolysin-deficient variants of Streptococcus pyogenes and S. dysgalactiae subsp. equisimilis may be overlooked as aetiological agents of pharyngitis.

Abstract: Variants of large colony β-haemolytic Lancefield group A, C and G streptococci that are non-haemolytic or α-haemolytic on sheep blood agar have been detected in clinical specimens due to their enhanced haemolytic activity when grown on a new selective and differential blood agar medium containing colistin, nalidixic acid and pH 7.5-adjusted PIPES buffer (CNA-P). The large colony Lancefield group C and G isolates were identified as Streptococcus dysgalactiae subsp. equisimilis by API 20 Strep classification and 16S rDNA profiling. The haemolytic activity of these variants on various blood agar media, including CNA-P, was closely similar to that of known streptolysin S-defective mutants of S. pyogenes and was blocked by addition of cholesterol, a specific inhibitor of the streptolysin O family of haemolysins. As haemolysin variants could be detected in large numbers in cultures from patients with clinical symptoms of pharyngitis it is suggested that they may function as primary pathogens in such infections. The high frequency with which haemolysin variants were isolated from clinical specimens during a 3-month trial (3%, 13% and 10%, respectively, of group A, C and G streptococcal isolates) indicated that a substantial proportion of streptococcal infections may go undetected if only conventional sheep blood agar media are used in clinical laboratories for the detection of β-haemolytic streptococci. As haemolysin variants have been implicated in the development of serious streptococcal sequelae, further investigation of the full extent of their contribution to streptococcal disease is indicated.

Antibiotic susceptibility and resistance testing: an overview.

Abstract: The results of in vitro antibiotic susceptibility testing can predict the clinical response to treatment and guide the selection of antibiotics The minimum inhibitory concentration (MIC) of an organism is the lowest concentration of an antibiotic that will inhibit its growth Bacteria are classified as sensitive, intermediate or resistant based on breakpoint MIC values that are arbitrarily defined and reflect the achievable levels of the antibiotic, the distribution of MICs for the organism and their correlation with clinical outcome Broth dilution, agar dilution and gradient diffusion (the 'E test'), where twofold serial dilutions of antibiotic are incorporated into tubes of broth, agar plates or on a paper strip, respectively, are different methods to measure the MIC of an organism The disk diffusion method defines an organism as sensitive or resistant based on the extent of its growth around an antibiotic-containing disk MIC values are influenced by several laboratory factors To ensure reproducible results, the laboratory must closely follow methods developed by the National Committee for Clinical Laboratory Standards, which defines standard growth media, incubation temperature and environment, the inoculum and quality control parameters

Isolation of Candida dubliniensis from the oral cavity of an HIV-positive child in Brazil.

Abstract: Candida dubliniensis is a newly-recognized Candida species and an important infectious pathogen, particularly for HIV-positive patients >From oral smear samples from the radix linguae of 173 HIV-positive children, we obtained four yeast isolates which took a blue-green color on CHROMagar Candida plate at 37 degrees C for 48 hours from one HIV-positive 3-year-old boy in Brazil The isolates were difficult to grow on potato dextrose agar plate at 42 degrees C, produced abundant chlamydospores on a cornmeal agar plate with Tween 80, and sprouted germ tubes in saline with horse serum, and the antigenic profile by CANDIDA CHECK test was useless Carbohydrate assimilation tests by ID32C showed no reference code number in the reference book The isolates were subjected to molecular biological assay of the DNA sequence of the large-subunit ribosomal DNA region (D1/D2) and randomly amplified polymorphic DNA (RAPD) The DNA sequence agreed with those of standard C dubliniensis strains, and therefore, the isolates were identified as C dubliniensis RAPD band pattern analysis indicated that the clinical isolates might summarize one genotype Although the child did not present oral lesions, the fungus might be latent for opportunistic infection

Analysis of recombinant protein expression by MALDI-TOF mass spectrometry of bacterial colonies.

Abstract: E. coli expressing soluble recombinant HIV antigens were analyzed directly by MALDI-TOF mass spectrometry (MS) from bacterial colonies picked from agar plates. An HIV envelope (ENV) antigen construct, penvA, was expressed in E. coli by transformation of the plasmid pPL/penvA-M. The plasmid was co-transformed into E. coli DH5 alpha cells with an equal quantity of the plasmid pKRR826, the parent vector without the penvA insert, and plated at medium density on L-agar plus ampicillin plates. A total of 24 colonies from four agar plates (six colonies per plate) were picked and transferred into 50% acetonitrile--0.1% trifluoroacetic acid aliquots for analysis by MALDI-TOF MS. The MS analysis detected 10 of 24 colonies expressing the recombinant protein; one colony expressed a mutant penvA protein; eleven of 24 colonies showed ions only from E. coli; and two of 24 colonies showed no detectable proteins. When E. coli transformed only with plasmid pPL/penvA-M were examined, all (10 of 10) colonies showed the penv insert by the MALDI-TOF MS method. The method is fast (less than 1.5 h for 24 colonies) and allows identification of colonies expressing intact or mutant proteins directly from culture plates without sample purification.

Quantificação de bactérias totais e esporuladas no solo

Abstract: This work studied the effect of the temperature and incubation time and of the inoculum dilution, in two culture media, on the quantification of total and sporulating bacteria. The quantitative and qualitative growth of total and sporulating bacteria depended on the growth medium, temperature, dilution and incubation time, as well as on the interaction of these factors. Tryptic Soil Agar medium presented a greater number of colony forming units (CFU) for total bacteria. However, for Bacillus spp. there were higher counts on Thorton medium. Colonies grown on Tryptic Soy Agar medium were of larger size and had a more clearly defined shape. An incubation temperature of 30°C yielded more CFU than incubation at 25°C, especially during the first days of incubation. Bacterial growth was fit to a mathematical model and corresponded to a third degree equation. Depending on the growth culture medium, incubation temperature and dilution, periods of maximum growth were between 4.9 and 6.9 days for total bacteria and between 4.4 and 7.2 days for Bacillus spp. Although decimal inoculum dilutions were used, proportions between counts based on different conditions ranged from 6.3 to 10.0 times for total bacteria and from 2.0 to 7.0 times for sporulating bacteria.

A logistic model of subsurface fungal growth with application to bioremediation

Abstract: The goal of this research was to determine the potential of the fungal sterol ergosterol as an indicator of fungal biomass and to determine the growth response of the transformed strain of T. virens (GvT6) to added substrate and changes in temperature. Experiments in liquid culture and agar plates containing a rich medium of glucose, yeast extract, and casein (GYEC), or a soil extract medium supplemented with maltose (SE) showed that the ergosterol content of GvT6 was greatest when grown on GYEC agar plates (14.02 mg/g dry biomass). For both media, plate cultures produced higher specific ergosterol values than liquid cultures. Changes in specific ergosterol values over time were generally not significant. A value of 5.41 mg ergosterol / g dry biomass, determined for SE plate cultures, was used to convert ergosterol values to biomass values in growth experiments in soil bioreactors. Data from experiments in soil bioreactors treated with different levels of substrate (0.5–8 mg maltose / g dry soil)...

Microorganism belonging to the genus bacillus and its use

Abstract: PROBLEM TO BE SOLVED: To provide a new microorganism having both functions of accelerating the fermentation of an organic substance and inhibiting the growth of fungus, and specific mycological characteristics. SOLUTION: This new microorganism is Bacillus cereus K12N strain (FERM P-17147) having following mycological characteristics. Swelling of cellular body: Nail 7%: (+); Anaerobic growth; (+); Starch decomposition: (+); VP: (-); Egg yolk: (-); Indole: (-); Growth at 60 deg.C; (-); Gram staining: (+); Position of spore: center and semi end position; Gross: none; Surface of its colony: wrinkled; Size of cell: 1.2×3-3.5 μm; Catalase: (+); Urea decomposition: (-); Oxydase: (+); Usual agar medium: (+); 10% sheep blood-added blood agar medium: (+); Hemolytic property: (+); Hydrogen sulfide: (-); Nitrate salt reduction: (+), etc. By using as a solid medium, the usual agar medium, and as a liquid medium, a meat extract medium, it is desirable to culture it purely.

Clinical evaluation of a novel chromogenic agar dipslide for diagnosis of urinary tract infections.

Abstract: The performance of a novel dipslide (DipStreak; Novamed, Israel) consisting of chromogenic agar (Uriselect 3; Sanofi Pasteur, France) and blood agar media was evaluated prospectively and compared to that of conventional urine culture for the diagnosis of urinary tract infection. A total of 1070 clean-catch urine specimens obtained from 251 hospitalized patients and 819 outpatients were processed. The overall performance of the DipStreak was as follows: sensitivity, 95.7%; specificity, 99.2%; agreement, 89.8%; accuracy, 98%; positive predictive value, 98.5%; and negative predictive value, 97.7%. A total of 270 urine specimens were positive by both DipStreak and conventional culture. The chromogenic agar allowed rapid identification of organisms in 211 (78.1%) cultures, while isolates in the other 59 (21.9%) cultures remained unidentified. The results indicate that the DipStreak device coupled with the Uriselect 3 agar represents a convenient and accurate method for inoculation of urine specimens, quantitation of bacteria, diagnosis of significant bacteriuria, and presumptive identification of isolates.