Showing papers on "Agar plate published in 2007"
TL;DR: A multi-faceted approach resulted in substantial improvement in the microbiological detection and isolation of Bartonella when compared to direct inoculation of a blood agar plate, and may assist in the diagnostic confirmation of bartonellosis in dogs and other animals.
175 citations
TL;DR: It is argued that cohabitation of these strains triggered antibiotic production via interspecific interactions and that the growth reduction of fungi was a side-effect caused by the sensitivity of the fungi to bacterial secondary metabolites.
123 citations
TL;DR: Tolerance to bile salts was investigated in forty Bacillus cereus strains, including 17 environmental isolates, 11 dairy isolate, 3 isolates from food poisoning outbreaks, and 9 other clinical isolates as mentioned in this paper.
Abstract: Tolerance to bile salts was investigated in forty Bacillus cereus strains, including 17 environmental isolates, 11 dairy isolates, 3 isolates from food poisoning outbreaks, and 9 other clinical isolates. Growth of all strains was observed at low bile salt concentrations, but no growth was observed on LB agar plates containing more than 0.005% bile salts. Preincubation of the B. cereus type strain, ATCC 14579, in low levels of bile salts did not increase tolerance levels. B. cereus ATCC 14579 was grown to mid-exponential growth phase and shifted to medium containing bile salts (0.005%). Global expression patterns were determined by hybridization of total cDNA to a 70-mer oligonucleotide microarray. A general stress response and a specific response to bile salts were observed. The general response was similar to that observed in cultures grown in the absence of bile salts but at a higher (twofold) cell density. Up-regulation of several putative multidrug exporters and transcriptional regulators and down-regulation of most motility genes were observed as part of the specific response. Motility experiments in soft agar showed that motility decreased following bile salts exposure, in accordance with the transcriptional data. Genes encoding putative virulence factors were either unaffected or down-regulated.
82 citations
TL;DR: ESBL-Bx is a sensitive and specific medium for the isolation of ESBL-producing Enterobacteriaceae from clinical samples and reduces by 27% the need for unnecessary identification and confirmation ofESBL testing when disregarding all colorless colonies growing on this medium.
Abstract: A novel chromogenic agar medium (ESBL-Bx; bioMerieux, Marcy l'Etoile, France) was compared to MacConkey agar supplemented with 2 mg ceftazidime/liter (MCKC) for the selective isolation and presumptive identification of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae directly from clinical samples. Of a total of 644 clinical specimens (including 551 fecal samples), 496 yielded no growth and 148 yielded growth on one or both media. Overall, 44 ESBL-producing Enterobacteriaceae strains (Escherichia coli [n=17], Enterobacter aerogenes [n=17], Klebsiella spp. [n=5], and Citrobacter freundii [n=5]) were isolated from 37 specimens by a combination of both methods after 18 to 24 h of incubation. The sensitivities were 97.7 and 84.1% for ESBL-Bx and MCKC, respectively, with 43 ESBL-positive strains isolated as colored colonies from 36 specimens on ESBL-Bx versus 37 ESBL-positive organisms isolated from 32 specimens on MCKC. The specificities by specimens were 89 and 91% for ESBL-Bx and MCKC, respectively. On either one of the two media, natural AmpC-hyperproducing Enterobacter spp. (n=25) and Citrobacter spp. (n=14) were the most common false positives as well as non-ESBL-producing Klebsiella oxytoca (n=18) on ESBL-Bx and Morganella morganii (n=10) on MCKC. We conclude that ESBL-Bx is a sensitive and specific medium for the isolation of ESBL-producing Enterobacteriaceae from clinical samples. The main advantages of ESBL-Bx over MCKC reside in its chromogenic character and its sensitivity and selectivity, which enabled the recovery and presumptive identification of most ESBL-producing Enterobacteriaceae within 24 h and reduced by 27% the need for unnecessary identification and confirmation of ESBL testing when disregarding all colorless colonies growing on this medium.
77 citations
TL;DR: The results indicate that this method is useful to detect extracellular proteases produced by both fungi as well as bacteria, and can be easily performed for screening of large number of microbial cultures.
74 citations
TL;DR: Pseudomonas aeruginosa bacteria colonies have been analyzed by laser-induced breakdown spectroscopy using nanosecond laser pulses to study the dependence of the LIBS spectrum on growth and environmental conditions.
73 citations
TL;DR: Scanning electron microscope analysis of two-week-old rice seedlings germinated from seeds previously inoculated with BR-25 and BR-15 revealed dense colonization at the root surfaces presumably using fimbriae on the bacterial cells.
Abstract: A total of 30 bacteria were isolated from the rhizoplane of rice cv. BR29 cultivated in Mymensingh, Bangladesh and from the seedlings obtained from surface-sterilized seeds of BR29. Upon screening, 6 isolates showed varying levels of phosphate solubilizing activity in both agar plate and broth assays using National Botanical Research Institute's phosphate medium. The bacterial isolates were identified based on their phenotypic and 16S rRNA genes sequencing data as Acinetobacter sp. BR-12, Klebsiella sp. BR-15, Acinetobacter sp. BR-25, Enterobacter sp. BR-26, Microbacterium sp. BRS-1 and Pseudomonas sp. BRS-2. The BR-25 exhibited highest phosphate solubilizing activity followed by BR-15. They grew rapidly in the liquid medium at pH 5 and 7 but almost no growth occurred at pH 3. The pH value of the culture medium was decreased with bacterial growth suggesting that they might secrete organic acids to solubilize insoluble phosphorus. Scanning electron microscope analysis of two-week-old rice seedlings germinated from seeds previously inoculated with BR-25 and BR-15 revealed dense colonization at the root surfaces presumably using fimbriae on the bacterial cells.
64 citations
Journal Article•
TL;DR: Out of the three body parts of all fishes, gut contents had highest actinomycetes population followed by gills and skin, and Kuster's agar medium was found to be suitable than the starch casein agar and glucose asparagine agar media.
Abstract: Actinomycetes were isolated from different organs viz. skin, gills and gut contents of three species of fishes viz. Mugil cephalus (Linnaeus, 1758), Chanos chanos (Forskal, 1775) and Etroplus suratensis (Bloch, 1780) using three different media from the Vellar estuary, situated along the southeast coast of India. Among the three fishes, M. cephalus harboured highest number of actinomycetes population in all the three body parts examined followed by C. chanos and E. suratensis. Out of the three body parts of all fishes, gut contents had highest actinomycetes population followed by gills and skin. Among the three media used for isolation of actinomycetes, Kuster's agar medium was found to be suitable than the starch casein agar and glucose asparagine agar media. Out of the 40 strains isolated, only six strains (LA-2, LA-8, LA-15, LA-20, LA-29 and LA-35) showed significant L-asparagianse activity and were taken up for further studies. Impact of various physical and chemical factors such as pH, temperature, sodium chloride concentration, carbon sources and amino acids on the growth of actinomycetes and L-asparaginase activity was also studied. Optimum growth and enzyme activity was noticed under pH 7 to 8, temperature 37 degrees C, 1-2% sodium chloride concentration, sucrose as carbon source and without any amino acids. Analysis of the cell components of the isolated strains has revealed the wall type-I (the wall type-I is typical for the genus Streptomyces) and the strains were micromorphologically similar to the genus Streptomyces. Hence, the morphological, physiological and biochemical along with the micromorphological results obtained for the L-asparaginase producing strains were compared and the strains were tentatively identified as Streptomyces aureofasciculus (LA-2), S. chattanoogenesis (LA-8), S. hawaiiensis (LA-15), S. orientalis (LA-20), S. canus (LA-29) and S. olivoviridis (LA-35).
61 citations
TL;DR: Using a novel agar medium, colonies of H2O2‐producing species including Streptococcus pyogenes were easily identified by the appearance of blue halos and the utility of the medium was illustrated by its successful application to the isolation of H1N1‐producing mutants from a non‐H2O 2‐producing stain of S.pyogenes.
Abstract: The classic method for H(2)O(2) detection involving Prussian blue formation was adapted to formulate a novel agar medium that makes possible in situ detection of H(2)O(2) produced by bacteria. Using this medium, colonies of H(2)O(2)-producing species including Streptococcus pyogenes were easily identified by the appearance of blue halos. The utility of the medium was further illustrated by its successful application to the isolation of H(2)O(2)-producing mutants from a non-H(2)O(2)-producing stain of S. pyogenes.
59 citations
TL;DR: Blood agar should be regarded as a first-line medium for culturing Mycobacterium species, it saves time, is cost-effective, is more sensitive than, and at least as rapid as the automated method, and for resource-limited countries in which the prevalence of tuberculosis is high.
Abstract: BackgroundMycobacterium species are grown using specific media that increase laboratory cost, thus hampering their diffusion in resource-limited countries. Preliminary data suggested that versatile blood agar may be also used for mycobacterial culture.MethodologyWe examined the growth of 41 different Mycobacterium species on 5% blood agar. Over a 24-month period we analysed isolation of mycobacteria after parallel inoculation of clinical specimens into both a reference automated system (BACTEC 9000 MB broth) and 5% blood agar slant tubes, after NaOH decontamination, and compared the cost of performing 1,000 analyses using these two techniques.ConclusionsMycobacterium reference species cultured on blood agar, with the exception of Mycobacterium ulcerans. Inoculation of 1,634 specimens yielded 95 Mycobacterium isolates. Blood agar performed significantly more efficiently than BACTEC 9000 MB broth (94 vs 88 isolates, P = 0.03). Decontamination of Candida albicans in 5 specimens by addition of amphotericin B in blood agar yielded one more M. tuberculosis isolate that could not be isolated in BACTEC broth. Uneven distribution of time to culture positivity for M. tuberculosis had a median (range) of 19±5 days using blood agar and 26±6 days using BACTEC 9000 MB broth. Cost for 1,000 analyses in France was estimated to be of 1,913 euros using the blood agar method and 8,990 euros using the BACTEC 9000 MB method. Blood agar should be regarded as a first-line medium for culturing Mycobacterium species. It saves time, is cost-effective, is more sensitive than, and at least as rapid as the automated method. This is of particular importance for resource-limited countries in which the prevalence of tuberculosis is high.
57 citations
Journal Article•
TL;DR: In this paper, the suitability of MRS-bile agar medium for enumeration of mixed probiotic cultures in cultured dairy products, beside an analysis of the morphological characteristics of probiotic colonies using SDM (stereo digital microscopy) method was analyzed.
Abstract: This paper contains a study on the suitability of MRS-bile agar medium for enumeration of mixed probiotic cultures in cultured dairy products, beside an analysis of the morphological characteristics of probiotic colonies using SDM (stereo digital microscopy) method. Three probiotic cultures (Lactobacillus acidophilus, Lactobacillus casei and bifidobacteria) were enumerated in various mixed culture compositions, i.e. AY (L. acidophilus and yogurt bacteria), CY (L. casei and yogurt bacteria), BY (bifidobacteria and yogurt bacteria), ABY (L. acidophilus, bifidobacteria and yogurt bacteria), ACY (L. acidophilus, L. casei and yogurt bacteria) and BCY (bifidobacteria, L. casei and yogurt bacteria). MRS-bile agar showed a good suitability for differential enumeration of probiotics in ACY culture composition under both aerobic and anaerobic conditions, differential and selective enumeration of probiotics in BCY culture composition (anaerobiosis and aerobiosis, respectively) and selective enumeration in ABY culture composition only for L. acidophilus under aerobiosis. Furthermore, by using the subtractive enumeration method (SEM) proposed in this article based on the subtraction of the colonies growth under aerobic condition (only L. acidophilus) from the colonies growth under anaerobic condition (both L. acidophilus and bifidobacteria), the number of bifidobacteria in ABY culture composition could also be well determined.
TL;DR: No differences were found in the abilities of the media surrounding these cells, either wild type or mutant, to wet a low-energy surface (freshly prepared polydimethylsiloxane); although, their contact angles were smaller than that of the medium harvested from the underlying agar.
Abstract: We compared the abilities of media from agar plates surrounding swarming and nonswarming cells of Salmonella enterica serovar Typhimurium to wet a nonpolar surface by measuring the contact angles of small drops. The swarming cells were wild type for chemotaxis, and the nonswarming cells were nonchemotactic mutants with motor biases that were counterclockwise (cheY) or clockwise (cheZ). The latter strains have been shown to be defective for swarming because the agar remains dry (Q. Wang, A. Suzuki, S. Mariconda, S. Porwollik, and R. M. Harshey, EMBO J. 24:2034-2042, 2005). We found no differences in the abilities of the media surrounding these cells, either wild type or mutant, to wet a low-energy surface (freshly prepared polydimethylsiloxane); although, their contact angles were smaller than that of the medium harvested from the underlying agar. So the agent that promotes wetness produced by wild-type cells is not a surfactant; it is an osmotic agent.
TL;DR: The findings of this experiment suggest that poloxamer gel could be used as an appropriate medium on which to conduct biofilm antibiotic susceptibility tests as it enables bacteria to be grown in a state representative of the infected surface from which the culture was taken.
Abstract: Wound infections, due to biofilms, are a constant problem because of their recalcitrant nature towards antibiotics. Appropriate antibiotic selection for the treatment of these biofilm infections is important. The traditional in vitro disc diffusion method for antibiotic selection uses bacterial cultures grown on agar plates. However, the form of bacterial growth on agar is not representative of how bacteria grow in wounds and other tissue sites as here bacteria grow naturally in a biofilm. The aim of this research was to test a more appropriate method for testing antimicrobial efficacy on biofilms and compare with the standard methods used for antibiotic sensitivity testing. Outer Membrane Protein analysis was performed on E.coli, Staphylococcus aureus, Pseudomonas aeruginosa, Proteus mirabilis and Acinetobacter juni when grown on Mueller Hinton agar ('quasi-biofilm state') and 30% Poloxamer hydrogel ('true- biofilm state). Susceptibility to antibiotics on 28 clinical isolates was determined using the modified Kirby Bauer disc diffusion method, on agar and 30% Poloxamer. Similar outer membrane proteins [OMPs] were identified in bacteria grown in a biofilm state and on a 30% poloxamer hydrogel, which were very different to the OMPs identified in bacteria grown on Mueller-Hinton agar and broth. There was a significant difference between the means of the clearance zones around the antibiotic discs on standard agar and poloxamer gels [P 0.05]. The findings of this experiment suggest that poloxamer gel could be used as an appropriate medium on which to conduct biofilm antibiotic susceptibility tests as it enables bacteria to be grown in a state representative of the infected surface from which the culture was taken.
TL;DR: To determine the frequency at which Chaetomium species are isolated in water-damaged buildings, and to examine the production of chaetoglobosins A and C in isolates of C. globosum obtained from different buildings, agar plates were grown on four different media.
Abstract: Chaetomium globosum, the most common species within this genus, produces chaetoglobosins A and C when cultured on building material. Relatively low levels of these compounds have been shown to be lethal to various tissue culture cell lines. This study had two major objectives: (1) to determine the frequency at which Chaetomium species are isolated in water-damaged buildings and (2) to examine the production of chaetoglobosins A and C in isolates of C. globosum obtained from different buildings. Out of 794 water-damaged buildings, Chaetomium species were isolated in 49% of these structures. C. globosum ATCC 16021 was grown on four different media: oatmeal agar (OA), potato dextrose agar (PDA), corn meal agar (CMA), and malt extract agar (MEA). After 4 weeks, fungal growth was evaluated based on colony diameter and the quantity of spores produced on agar plates. In addition, production of chaetoglobosin A and C was monitored using high performance liquid chromatography. Colony diameter, spore production, and mycotoxin production by C. globosum were the highest on OA. Out of 30 C. globosum isolates cultured on OA for 4 weeks, 16 produced detectable amounts of chaetoglobosin A and every isolate produced chaetoglobosin C.
TL;DR: Results show that surface plating samples on BAT agar, followed by incubating plates at 43 degrees C for 3 days provide the most suitable conditions to enumerate ten strains of three species of Alicyclobacillus most commonly responsible for spoilage of beverages.
TL;DR: The isolate Aspergillus niger shows maximum production of both extracellular and intracellular enzyme, and the colony diameter on the solid surface media shows high correlation with quantitative production of tannase.
TL;DR: The sensitivity for detection of MS is higher for modified MSB agar medium when compared with MSB Agar medium and the mMSB-kit can be an important contributor for the evaluation of MS as a caries risk factor.
Abstract: Objectives : The evaluation of Mutans streptococci (MS) is one of the index for caries risk. Dentocult TM and CRT TM are commercial kits to detect and evaluate MS, conveniently. However, the evaluation of MS has also been carried out simply using an instruction manual. But the instruction manual is not easy to use for evaluation of MS. The aim of this study was to examine the utility of modified Mitis-Salivalius Bacitracin (MSB) agar medium compared with MSB agar medium and commercial kits, and to establish a convenient kit (mMSB-kit) using modified MSB agar. Methods : The MS in stimulated saliva from 27 subjects were detected by MSB, modified MSB agar medium and commercial kits. Laboratory and clinically isolated strains of MS were similarly evaluated. The ratios of MS in detected bacteria were compared by ELISA. Results : The scores using an mMSB-kit on the basis of modified MSB agar medium were tabulated. Saliva samples showed different levels of MS between culture methods and the commercial kit. Some samples which were full of MS were not detected by the commercial kit. The detection of MS by modified MSB agar medium and mMSB-kit were significantly higher when compared with MSB agar medium, CRT TM , (P< .01) and Dentocult SM TM (P<.05). Conclusion : The sensitivity for detection of MS is higher for modified MSB agar medium when compared with MSB agar medium. The mMSB-kit can be used simply, and can be an important contributor for the evaluation of MS as a caries risk factor. (Eur J Dent 2007;1:31-39)
TL;DR: The prevalence of GBS carriage in this population-based study is a reliable estimate considering the sensitivity of the microbiological methods used, the rate of attendance of pregnant women to clinical and laboratory settings and the compliance to the protocol.
Abstract: Aims: To assess the sensitivity of a combined selective broth enrichment technique plus selective plating for the detection of group B streptococcus (GBS) colonisation in a large cohort of pregnant women from North-Eastern Italy. Methods: During 2002–2005, 5020 pregnant women were screened between the 35th and the 37th week of gestation. A lower vaginal sample and a rectal sample were collected and inoculated onto LIM broth and a selective colistin aztreonam blood agar plate (CAP). Direct agar plates were examined after 18–24 hours and, if negative, after 48 hours. LIM broth was subcultured after 18–24 hours onto a Columbia blood agar plate. All colonies suggestive for GBS were submitted to phenotypic identification. Results: 901 Women (17.9%) were positive for GBS. On 728 positive samples, corresponding to patients enrolled between 2003 and 2005, the results of selective direct plating and selective broth enrichment were compared. A total of 561 (77.1% of positive samples, corresponding to 13.9% of patients) were positive on direct selective agar; an additional 167 isolates (22.9% of samples, 4.1% of patients) were recovered from the LIM broth subculture. Conclusions: The prevalence of GBS carriage in this population-based study is a reliable estimate considering the sensitivity of the microbiological methods used, the rate of attendance of pregnant women to clinical and laboratory settings and the compliance to the protocol. Results confirm that the combination of selective enrichment broth and selective direct plating is a time-saving and sensitive method.
TL;DR: Three previously unreported substrates for the detection of β‐glucosidase activity in clinically relevant bacteria are evaluated and their performance with a range of known substrates in an agar medium is compared.
Abstract: Aims: To evaluate three previously unreported substrates for the detection of β-glucosidase activity in clinically relevant bacteria and to compare their performance with a range of known substrates in an agar medium.
Methods and Results: The performance of 11 chromogenic β-glucosidase substrates was compared using 109 Enterobacteriaceae strains, 40 enterococci and 20 strains of Listeria spp. Three previously unreported β-glucosides were tested including derivatives of alizarin, 3′,4′-dihydroxyflavone and 3-hydroxyflavone. These were compared with esculin and β-glucoside derivatives of 3,4-cyclohexenoesculetin, 8-hydroxyquinoline and five indoxylics. All substrates yielded coloured precipitates upon hydrolysis in agar. Alizarin-β-d-glucoside was the most sensitive substrate tested and detected β-glucosidase activity in 72% of Enterobacteriaceae strains and all enterococci and Listeria spp. The two flavone derivatives showed poor sensitivity with Gram-negative bacteria but excellent sensitivity with enterococci and Listeria spp.
Conclusions: Alizarin-β-d-glucoside is a highly sensitive substrate for detection of bacterial β-glucosidase and compares favourably with existing substrates. β-glucosides of 3′,4′-dihydroxyflavone and 3-hydroxyflavone are effective substrates for the detection of β-glucosidase in enterococci and Listeria spp.
Significance and Impact of the Study: The data presented allow for informed decisions to be made regarding the optimal choice of β-glucosidase substrate for detection of pathogenic and/or indicator bacteria.
TL;DR: Twenty-nine out of 33 suspected Xcm strains isolated from plants, soil and insects using CCA were pathogenic when inoculated onto banana plants, indicating that CCA can be a reliable tool in isolating Xcm populations.
Abstract: A semiselective medium was developed for isolating Xanthomonas campestris pv. musacearum (Xcm) from infected banana plants, soil and insect vectors. The new medium was named cellobiose-cephalexin agar (CCA) and it contained (L−1): 1 g yeast extract, 1 g glucose, 1 g peptone, 1 g NH4Cl, 1 g MgSO4·7H2O, 3 g K2HPO4, 1 g beef extract, 10 g cellobiose, 14 g agar, 40 mg cephalexin, 10 mg 5-fluorouracil and 120 mg cycloheximide. The medium was evaluated for selectivity using 21 bacterial isolates and for plating efficiency using Xcm. The bacterial isolates included a soilborne Xanthomonas species and three pathogenic Xanthomonas strains that infect cassava, cabbage and beans. Although the plating efficiency of Xcm on CCA was lower (59%) than on non-selective yeast extract peptone glucose agar (YPGA), its selectivity was significantly higher, averaging 60 and 82%, when isolating from banana fruits and soil, respectively. CCA was also superior when isolating Xcm from insect vectors, with selectivity of 48–75%, compared with 8–17% on YPGA. Xanthomonas campestris pv. phaseoli did not grow on CCA, while X. campestris pv. campestris and X. axonopodis pv. manihotis grew, but their colonies were smaller than those of Xcm. Twenty-nine out of 33 suspected Xcm strains isolated from plants, soil and insects using CCA were pathogenic when inoculated onto banana plants, indicating that CCA can be a reliable tool in isolating Xcm populations. The medium should prove useful in studies on ecology, epidemiology and management of the banana bacterial wilt pathogen that is currently ravaging bananas in East and Central Africa.
TL;DR: It is found that VRE-BMX provided improved recovery of VRE from stool specimens, with the added advantage of being able to differentiate between vancomycin-resistant E. faecium and E. Faecalis, a feature useful for infection control purposes that is not a function of BEAV.
Abstract: The development of reliable and rapid methods for the identification of patients colonized with vancomycin-resistant enterococci (VRE) is central to the containment of this agent within a hospital environment. To this end, we evaluated a prototype chromogenic agar medium (VRE-BMX; bioMerieux, Marcy l'Etoile, France) used to recover VRE from clinical specimens. This medium can also identify isolated colonies as either vancomycin-resistant Enterococcus faecium or Enterococcus faecalis, based on distinct colony colors. We compared the performance of VRE-BMX with bile esculin azide agar supplemented with vancomycin (BEAV). For this study, 147 stool samples were plated on each test medium and examined after 24 and 48 h of incubation. At 24 h, the sensitivity and specificity of each medium were as follows: BEAV, 90.9% and 89.9%, respectively; VRE-BMX, 96.4% and 96.6%, respectively. The positive predictive values (PPV) of VRE-BMX and BEAV at 24 h were 89.8% and 80.7%, respectively. VRE-BMX provided the identification of 10 isolates of vancomycin-resistant E. faecalis and 4 isolates of vancomycin-resistant E. faecium that were not recovered by BEAV. Further, VRE-BMX was capable of identifying patients colonized with both E. faecium and E. faecalis, a feature useful for infection control purposes that is not a function of BEAV. In terms of the recovery of vancomycin-resistant E. faecium and E. faecalis, the sensitivity and PPV were as follows: BEAV, 75.7% and 74.6%, respectively; VRE-BMX, 95.5% and 91.3%, respectively. In this initial evaluation, we found that VRE-BMX provided improved recovery of VRE from stool specimens, with the added advantage of being able to differentiate between vancomycin-resistant E. faecalis and E. faecium. Extending the incubation period beyond 24 h did not significantly improve the recovery of VRE and resulted in decreased specificity.
Journal Article•
TL;DR: Combination of agar plate culture and formalin ether concentration is recommended to obtain higher efficacy in detection of S. stercoralis, especially in north of Iran.
Abstract: Background: Strongyloides stercoralis is a common parasitic nematode in Iran, especially in north of the country. The early diagnosis and treatment of S. stercoralis is crucial to prevent complicated cases of strongyloidiasis. The value of the preference of agar plate culture, in detection of S. stercoralis compared to formalin ether concentration method, reported in different studies in the world is variable from 1.6 to 6 times. Therefore, the current study was performed to evaluate the efficacy of agar plate on some isolates from north of Iran.
Methods: Nine hundred stool samples were randomly collected from rural areas of Mazandaran Province, northern Iran. All samples were examined by agar plate culture, formalin ether concentration and direct smear.
Results: Agar plate was 2 times superior to formalin ether; however, it showed some false negative results, too. The direct method could only detect cases of hyperinfection strongyloidosis.
Conclusion: On the whole, combination of agar plate culture and formalin ether concentration is recommended to obtain higher efficacy.
TL;DR: There was positive correlation with respect to the microorganisms present in the OP biofilm and AC for the 4 proposed treatments, indicating that the decrease of OP contamination leads to AC contamination as well.
Abstract: In addition to an initial socket discomfort, ocular prosthesis (OP) installation may allow the adherence of fungi and/or bacteria due to the superficial characteristics of the prosthesis' material, use of inadequate cleansing solutions and methods, or because the void located between the internal portion of the prosthesis and the anophthalmic cavity (AC) mucosa. Objective: The aim of this study was to evaluate OP biofilm formation and the level of contamination of the internal portion of the OP and the AC in 24 patients. Material and Methods: Material was collected from the AC at the beginning of the study and 15 days after cleansing of the OP with 3 cleansing solutions: a neutral liquid soap, a multiuse solution for contact lens (Complete) and 0.12% chlorhexidine (Periogard). The collected materials were sowed in Petri dishes containing selective media for aerobic and facultative microorganisms, specifically staphylococci (Hipersalt agar with egg yolk), aerobic microorganisms (Brain Heart Infusion Blood Agar), streptococci (Mitis salivarius Agar), gram-negative bacilli (MacConkey Agar) and yeasts (Chromagar CandidaTM), incubated at 35oC or 37oC and the number of colony forming units were counted. Data were analyzed statistically by ANOVA, Friedman's test and Spearman's correlation. Results: Aerobic microorganisms, gram-negative bacilli and S. aureus were found in the OP biofilm and in the AC. There was statistically significant difference (p<0.05) between the number of microorganisms before and after the use of the cleansing solutions. Conclusion: There was positive correlation with respect to the microorganisms present in the OP biofilm and AC for the 4 proposed treatments, indicating that the decrease of OP contamination leads to AC contamination as well.
TL;DR: Different pulsotypes were present in the different categories of seafood products and were not specific to one producer, and the genetic diversity observed in the products was not related to the prevalence found at the manufacturing site.
TL;DR: Six isolates of Exiguobacterium aurantiacum were obtained from patients with bacteraemia, three of whom had myeloma, and were susceptible to all antimicrobial agents tested and were uniform in their fatty acid and mass spectrum profiles.
TL;DR: Examination of the fate of WS-founded populations in either multiple-colonies or single mega-colony agar plate microcosms demonstrated that the loss of WS lineages could be reduced under conditions in which the rapid spreading colony phenotype could dominate nutrient and oxygen access more effectively than competing SM/SM-like genotypes.
Abstract: Bacterial adaptation to new environments often leads to the establishment of new genotypes with significantly altered phenotypes. In the Wrinkly Spreader (WS), ecological success in static liquid microcosms was through the rapid colonisation of the air-liquid interface by the production of a cellulose-based biofilm. Rapid surface spreading was also seen on agar plates, but in this two-dimensional environment the WS appears maladapted and rapidly reverts to the ancestral smooth (SM)-like colony genotype. In this work, the fitness of WS relative to SM in mixed colonies was found to be low, confirming the WS instability on agar plates. By examining defined WS mutants, the maladaptive characteristic was found to be the expression of cellulose. SM-like revertants had a higher growth rate than WS and no longer expressed significant amounts of cellulose, further confirming that the expression of this high-cost polymer was the basis of maladaptation and the target of compensatory mutation in developing colonies. However, examination of the fate of WS-founded populations in either multiple-colony or single mega-colony agar plate microcosms demonstrated that the loss of WS lineages could be reduced under conditions in which the rapid spreading colony phenotype could dominate nutrient and oxygen access more effectively than competing SM/SM-like genotypes. WS-like isolates recovered from such populations showed increased WS phenotype stability as well as changes in the degree of colony spreading, confirming that the WS was adapting to the two-dimensional agar plate microcosm.
TL;DR: To test the bacterial penetrability of disposable non-woven drapes used specifically for total hip arthroplasty, six brands of disposable drape were tested and some were more impenetrable than others and some remained so or allowed passage of fewer than 100 colony-forming units at 90 minutes.
Abstract: Purpose. To test the bacterial penetrability of disposable non-woven drapes used specifically for total hip arthroplasty. Methods. 12 round agar plates were inoculated with 107 colony-forming units/ml of coagulase-negative staphylococci (CNS) and incubated in air at 37oC for 18 hours to obtain a semi-confluent growth of organisms. Six brands of disposable drapes were tested; each was assigned to 2 plates. Each disposable drape was placed between a round agar plate and an inverted square agar plate filled with blood agar. After 30 and 90 minutes, the square agar plates were removed and incubated for 48 hours and inspected for growth of CNS. Results. Bacterial penetration was time dependant. Certain brands of drapes were more impenetrable than others; none was impenetrable at all time points, but most remained so or allowed passage of fewer than 100 colony-forming units at 90 minutes. Conclusion. It is recommended that drapes be rigorously tested with regard to their resistance to bacterial penetration.
TL;DR: Third-stage larvae cultured by the AP method established patent infection in naturally permissive laboratory hosts, although the yield of adult worms was reduced compared with animals infected with L3 obtained by Baermann culture.
Abstract: An agar plate (AP) method has been developed for culturing infectious larvae of the hookworm Ancylostoma ceylanicum. The third-stage larvae reared using the AP method displayed similar morphology to those cultured using Baermann or Harada-Mori coproculture techniques. The yield of viable larvae from the AP method (50%) was comparable to that of the Baermann (47%), and both were superior to Harada-Mori (2.1%). Third-stage larvae cultured by the AP method established patent infection in naturally permissive laboratory hosts, although the yield of adult worms was reduced compared with animals infected with L3 obtained by Baermann culture. The AP method is useful for defining growth requirements for hookworm development, as well as characterizing the effects of bacterially expressed compounds on hookworm larvae in vivo.
01 Jan 2007
TL;DR: The ethanol extract of the £owers showed antibacterial activity against all the tested vibriostrains (Vibrio alginolyticusVIB 283, V.campbelliVIB298,V.harveyiSF1,V-minicus VIB298), and the bacteria were tested in three replicates with reproducible results.
Abstract: In aquaculture, bacterial diseases create challenging problems because they are di⁄cult to control and often result in sudden, severe economic losses. Some of the major ¢sh pathogen bacteria cause vibriosis or haemorrhagic septicaemia with extensive skin lesions and damage internal organs such as the liver, kidneyand spleen inwildmarine ¢sh, freshwater ¢sh and other aquatic animals. Treatment of bacterial diseases is mainly based on the use of antibiotics. However, environmental concerns and the emergence of antibiotic-resistant strains of ¢sh common pathogens limit the value of these compounds and has created a need for new antimicrobial agents. The £owers of Rosa chinensis Jacq. were obtained at a local drug store (Qingdao, China) and extracted by 95% ethanol (0.2 g £owersmL 1 ethanol) at room temperature for 7 days to obtain a crude extract. The antibacterial activity of the extract against bacteria was examined by the disc diiusion method on agar plates (Nagashima, Kikuchi, Shimakura & Shiomi 2003). Eleven bacteria strains (Table1) were cultured in sterilised 2216E medium [5 g peptone, 1g yeast, 0.1g FePO4, Sinopharm Chemical Reagent, (Sinopharm Chemical Reagent Co. Ltd., Shanghai, China) 1L seawater at 33 0.8 g L 1 salinity, pH57.6] at 28 1C or LB medium [10 g peptone, 5 g yeast, 10 g NaCl, Sinopharm Chemical Reagent (Sinopharm Chemical Reagent Co. Ltd., Shanghai, China),1L distilled water, pH57.0] at 37 1C for 24 h. The cultures were diluted with 0.85% NaCl to a concentration of 10 CFUmL 1 and 50 mL of the bacterial suspension was seeded on 2216E or LB agar plates [15 gagar L 1 distilled water or seawater, Sinopharm Chemical Reagent (Sinopharm Chemical Reagent Co. Ltd., Shanghai, China)]. Extract (0.1mL from 20mg £owers) was applied to steriled paper discs and allowed to dry, placed on the agar plates and then incubated at 28 or 37 1C for 24 h.The bacteriawere tested in three replicates with reproducible results. Statistical analysis was performed using the commercial software program SPSS10.0. The ethanol extract of the £owers showed antibacterialactivityagainstall thetestedvibriostrains (Vibrio alginolyticusVIB 283,V. alginolyticusVIB 284,V. anguillarumCW1,V.campbelliVIB298,V.harveyiSF1,V.minicus VIB298,V. parahaemolyticus FYZ 8621.4,V. vulni¢cus VIB310)andthreenon-vibriostrainsincludingEdwardsiella tarda CW7, Aeromonas hydrophila1-2017 and A. caviae1-1960. The diameters of the growth inhibition zones ranged from 11 to 20mm when 0.1mL (20mg £owers) of theextractwasused (Table1). One kilogramof the £owers of R. chinensis Jacq. was extracted with 5 L 95% ethanol for 7 days. The crude extract was ¢ltered under reduced pressure, and then concentratedundervacuumusingarotaryevaporator. Theconcentratedethanolextract(90 g)wasthenchromatographed on a vacuum silica gel column. Elution was performed using a polarity-increasing mixture of CHCl3^MeOH. This process collected 29 fractions, whichwere tested for theantibacterialactivityagainst V. anguillarumCW1. Fractions 21^23 showed themost pronounced antibacterial activity. These fractions (10 g) were then vacuum column chromatographed Aquaculture Research, 2007, 38, 1110^1112 doi:10.1111/j.1365-2109.2007.01745.x
TL;DR: The inability of the CT-SMAC agar medium to specifically select for E.coli O157:H7 was confirmed by the results of this study and calls for further improvement of affordable methods for the selective isolation of E. coli O157;H7 in the presence of large numbers of interfering bacteria capable of growing on CT- SMAC.
Abstract: E. coli O157:H7 is recognised as an important human pathogen world-wide and has been associated with diseases such as haemorrhagic colitis (HC), haemolytic uraemic syndrome (HUS) and thrombotic thrombocytopaenic purpura (TTP). Accurate laboratory detection of E. coli O157:H7 is important for diagnostic purposes and to justify epidemiological data on E. coli O157:H7. A well-known phenotypic characteristic of E. coli O157:H7 bacteria is their inability to ferment sorbitol. This characteristic is often used to isolate these organisms from food and water using selective agar medium such as SMAC. However, the high number of false positive results obtained by a number of researchers when selectively screening for E. coli O157: H7 on CT-SMAC has prompted an investigation to determine which other sorbitol-negative bacteria also grow on CT-SMAC. The agar medium used for the investigation consisted of Sorbitol MacConkey agar (SMAC) supplemented with Cefiximetellurite (CT). All sorbitol-negative colonies obtained from CT-SMAC, after selective enrichment and IMS were identified using the Biolog microbial identification system. The majority of sorbitol-negative isolates identified were Burkholderia, Pseudomonas, Vibrio and Aeromonas spp. Only two E. coli O157:H7 isolates were identified with Biolog and confirmed with a polymerase chain reaction (PCR) specific for the shiga toxin 1 (Stx1) genes and with O157 and H7 antisera. The inability of the CT-SMAC agar medium to specifically select for E.coli O157:H7 was confirmed by the results of this study. These observations call for further improvement of affordable methods for the selective isolation of E. coli O157:H7 in the presence of large numbers of interfering bacteria capable of growing on CT-SMAC.