Coexistence of Vibrio cholerae O1 and O139 Bengal in plankton in Bangladesh.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
R R Colwell
Publications and source records attributed to R R Colwell.
Temperature-induced recovery of Vibrio cholerae from the viable but nonculturable state: growth or resuscitation?
Vibrio cholerae cells were incubated at 4 degrees C in nutrient-limited artificial seawater (ASW) microcosms. Plate counts declined from 8 x 10(5) to less than 2 c.f.u. ml-1 in about 23 d. When samples of microcosms were shifted to 30 degrees C, plate counts increased to 2.2 x 10(5) c.f.u. ml-1 in 72 h. An experiment was performed to determine whether culturable cells obtained after temperature upshifts were the result of 'resuscitation', or outgrowth, of nonculturable cells or of cell division and growth of the few culturable cells that remained in samples. Prior to temperature upshift, samples from the microcosms were diluted 10- and 100-fold in filter-sterilized (0.1 microns) ASW from the microcosms. Undiluted, 1/10, and 1/100 diluted samples recovered culturability to about 2.2 x 10(5) c.f.u. ml-1 within 72 h of temperature upshift. If resuscitation of nonculturable cells had occurred, the resultant number of culturable cells in diluted samples would have been 1/10 and 1/100 that of undiluted samples, respectively. In microcosms where plate counts had declined to less than 1 c.f.u. ml-1, 1/100 diluted samples did not regain culturability, i.e. no culturable cells remained from which growth could occur. Our conclusions are that in the experiments reported here, recovery of culturable cells on temperature upshifts resulted from growth and that there were no growth-inhibiting factors in the spent growth medium, supported by the finding that about 10(2) recovered V. cholerae cells ml-1 inoculated into filter-sterilized microcosm ASW grew to about 6.2 x 10(5) c.f.u. ml-1 in 24 h, confirming that V. cholerae is capable of significant growth in ASW.
Colony Count, Microbial↗
Decrease in culturability of Vibrio cholerae caused by glucose.
The culturability of Vibrio cholerae O1 serotype Inaba strain 569B was decreased by the addition of glucose to cell suspensions in starvation media. A similar effect was observed with sucrose, maltose, and fructose. We term this inhibitory effect glucose shock. It was not observed with arabinose or xylose or with carboxylates, such as acetate and pyruvate. No acidification of the medium occurred in the presence of these carbohydrates. Glucose shock was prevented by the addition of nitrogen or phosphorus sources. In the presence of phosphate, the bacterium produced formic acid from glucose. The phenomenon of glucose shock was also observed in V. cholerae O1 serotype Inaba strain RIMD 2203082 but not in strain RIMD 2203088 (O1 Inaba), IID 936 (O1 Ogawa), or RIMD 2214034 (non-O1). The culturability of Escherichia coli, Enterobacter aerogenes, and Listonella anguillarum did not decrease in starvation media with added glucose. Hence, the phenomenon should have ecological significance in determining the distribution of bacteria in marine ecosystems in situations where carbohydrates are abundant, but nitrogen and phosphorus are limiting.
Glucose↗
Enterobacterial repetitive intergenic consensus sequences and the PCR to generate fingerprints of genomic DNAs from Vibrio cholerae O1, O139, and non-O1 strains.
Enterobacterial repetitive intergenic consensus (ERIC) sequence polymorphism was studied in Vibrio Cholerae strains isolated before and after the cholera epidemic in Brazil (in 1991), along with epidemic strains from Peru, Mexico, and India, by PCR. A total of 17 fingerprint patterns (FPs) were detected in the V. cholerae strains examined; 96.7% of the toxigenic V. cholerae O1 strains and 100% of the O139 serogroup strains were found to belong to the same FP group comprising four fragments (FP1). The nontoxigenic V. cholerae O1 also yielded four fragments but constituted a different FP group (FP2). A total of 15 different patterns were observed among the V. cholerae non-O1 strains. Two patterns were observed most frequently for V. cholerae non-01 strains, 25% of which have FP3, with five fragments, and 16.7% of which have FP4, with two fragments. Three fragments, 1.75, 0.79, and 0.5 kb, were found to be common to both toxigenic and nontoxigenic V. cholerae O1 strains as well as to group FP3, containing V. cholerae non-O1 strains. Two fragments of group FP3, 1.3 and 1.0 kb, were present in FP1 and FP2 respectively. The 0.5-kb fragment was common to all strains and serogroups of V. cholerae analyzed. It is concluded from the results of this study, based on DNA FPs of environmental isolates, that it is possible to detect an emerging virulent strain in a cholera-endemic region. ERIC-PCR constitutes a powerful tool for determination of the virulence potential of V. cholerae O1 strains isolated in surveillance programs and for molecular epidemiological investigations.
Bacterial Toxins↗
Environmental reservoir of Vibrio cholerae. The causative agent of cholera.
Explore the source record for details and available documents.
Animals↗
Biodiversity and utilization of microorganisms.
Explore the source record for details and available documents.
Animals↗
Biodiversity and release of genetically engineered organisms: a partnership of value.
Explore the source record for details and available documents.
Bacteria↗
Serum antibody responses of divers to waterborne pathogens.
To assess the significance of exposure of divers to waterborne pathogens, specific immunoglobulin G serum antibody responses to Pseudomonas and Aeromonas isolates recovered from dive sites from the respiratory tracts of nine experienced divers and seven diving trainees working in the Chesapeake Bay area over a 6- to 18-month period were measured. A significant increase in the frequency of isolation of these organisms from respiratory surfaces both groups of divers after each dive was noted, with the divers' ears being the predominant recovery site (48%; P < 10(-8), chi-square). The acute serum responses of the majority of experienced divers (83%) showed evidence of preexisting antibody to these potential pathogens, whereas the acute serum response of only 32% of naive divers showed such evidence (P < 10(-8), chi-square). Six months into their training, the rate of seroresponse of the trainees to organisms recovered after their first dives increased to 61% (P = 0.003, chi-square), suggesting that repeated exposure in necessary for generation of a specific systemic immunologic response. The rate of acquisition of a new seroresponse to recovered organisms was approximately 12% per dive for both groups of divers, suggesting that there is continuous exposure to, and infection with, new strains present in the water during dives. These data suggest that, in cases in which systemic antibody is important for protection, there are various levels of susceptibility to waterborne potential pathogens in both experienced and inexperienced divers.
Adult↗
Direct sequencing of the polymerase chain reaction-amplified 16S rRNA gene of Flavobacterium gondwanense sp. nov. and Flavobacterium salegens sp. nov., two new species from a hypersaline Antarctic lake.
Phenotypic data and phospholipid ester-linked fatty acid profiles indicate that pigmented bacterial strains isolated from a hypersaline Antarctic lake are members of the "flavobacterium-bacteroides" phylum and may represent new taxa. Nearly complete 16S rRNA sequences were obtained for representative strains by directly sequencing the polymerase chain reaction-amplified 16S rRNA gene. Sequence signatures confirmed that these organisms were members of the flavobacterium-bacteroides phylum. A phylogenetic analysis, in which the sequences of the Antarctic strains were compared with a large number of sequences available for members of the flavobacterium-bacteroides phylum, showed that the Antarctic strains were phylogenetically distinct. The new species cluster with a group of organisms that contains the type species of the genus Flavobacterium, Flavobacterium aquatile. Two new species are described, for which the names Flavobacterium gondwanense and Flavobacterium salegens are proposed; strains ACAM 44 (= DSM 5423) and ACAM 48 (= DSM 5424) are the type strains of F. gondwanense and F. salegens, respectively.
Antarctic Regions↗
Enumeration of Vibrio vulnificus on membrane filters with a fluorescently labeled oligonucleotide probe specific for kingdom-level 16S rRNA sequences.
Vibrio vulnificus was enumerated on membrane filters after hybridization with a fluorescent oligonucleotide eubacterial probe. Cells were hybridized in liquid buffer or directly on membrane filters. There was no significant difference between fluorescent oligonucleotide direct counts and acridine orange direct counts (P > 0.05). Liquid buffer hybridization was preferable to direct filter hybridization.
Acridine Orange↗
Development and evaluation of a rapid, simple, sensitive, monoclonal antibody-based co-agglutination test for direct detection of Vibrio cholerae 01.
Cholera epidemics caused by Vibrio cholerae 01 continue to represent a major public health concern in many developing countries. A rapid and simple test kit for the detection of V. cholerae 01 has been developed. The kit, CholeraScreen is a monoclonal antibody-based, co-agglutination test and is used directly with stool specimens. It does not include culturing the specimen and is performed without the need for sophisticated laboratory equipment. Specificity of the test was demonstrated, using 118 reference cultures, to which cross-reactions were not observed. Preliminary results of field trials carried out in Guatemala and Bangladesh demonstrated that the test is equally sensitive as conventional culture methods in detecting V. cholerae and, in many cases, more sensitive. The CholeraScreen test is simple, specific, and does not require culturing procedures, making it suitable for direct detection of cells of V. cholerae in clinical specimens, even in the field. Also, the test requires less than five minutes to complete.
Agglutination Tests↗
Determination of plasmid DNA concentration maintained by nonculturable Escherichia coli in marine microcosms.
The concentration of plasmid pBR322 DNA in nonculturable Escherichia coli JM83 was measured to determine whether the plasmid concentration changed during survival of E. coli in marine and estuarine water. E. coli JM83 containing the plasmid pBR322 was placed in both sterile seawater and sterile estuarine water and analyzed for survival (i.e., culturability) and plasmid maintenance. The concentration of pBR322 DNA remained stable in E. coli JM83 for 28 days in an artificial seawater microcosm, even though nonculturability was achieved within 7 days. E. coli JM83 incubated in sterile natural seawater or sterile estuarine water did not reach nonculturability within 30 days. Under all three conditions, plasmid pBR322 DNA was maintained at approximately the initial concentration. Cloning of DNA into the plasmid pUC8 did not alter the ability of E. coli to maintain vector plasmid DNA, even when the culture was in the nonculturable state, but the concentration of plasmid DNA decreased with time in the microcosm. We conclude that E. coli is able to maintain plasmid DNA while in the nonculturable state and that the concentration at which the plasmid is maintained appears to be dependent upon the copy number of the plasmid and/or the presence of foreign DNA.
DNA, Bacterial↗
Distribution of viruses in the Chesapeake Bay.
High virus counts were found in water samples collected from the Chesapeake Bay. Viruses were enumerated by ultracentrifugation of water samples onto grids which were visualized by transmission electron microscopy. Virus counts in September 1990, April 1991, June 1991, August 1991, and October 1991 ranged between 2.6 x 10(6) and 1.4 x 10(8) viruses ml-1 with a mean of 2.5 x 10(7) viruses ml-1. Virus counts were usually at least three times higher than direct bacterial counts in corresponding samples. Virus counts in August and October were significantly higher than at the other sampling times, whereas bacterial counts were significantly lower at that time, yielding mean virus-to-bacterium ratios of 12.6 and 25.6, respectively. From analysis of morphology of the virus particles, it is concluded that a large proportion of the viruses are bacteriophages. The high virus counts obtained in this study suggest that viruses may be an important factor affecting bacterial populations in the Chesapeake Bay, with implications for gene transfer in natural aquatic bacterial populations and release of genetically engineered microorganisms to estuarine and coastal environments.
Bacteria↗
Occurrence of resistance to vibriostatic compound 0/129 in Vibrio cholerae 01 isolated from clinical and environmental samples in Bangladesh.
Fifty-one Vibrio cholerae 01 strains isolated from 734 natural water and plankton samples and 31 rectal swabs were examined. Of these strains, 32 (62.7%) were found to be resistant to vibriostatic compound 0/129. When antibiograms using the antibiotics ampicillin, tetracycline, chloramphenicol, trimethoprim-sulfamethoxazole, furoxan, and gentamicin were done, it was observed that there was a correlation of sensitivity to 0/129 with selected antibiotics. Only the Ogawa E1 Tor (72% of strains resistant) and Inaba classical (28% of strains resistant) biotypes of V. cholerae 01 showed resistance to 0/129. On the other hand, all Inaba E1 Tor and Ogawa classical strains were susceptible to 0/129. The 32 0/129-resistant and 19 0/129-sensitive isolates of V. cholerae 01 were tested for the presence of plasmid DNA. Only two strains isolated from the environment were found to carry a plasmid, and they were also found to be resistant to 0/129 and gentamicin. Thus, 0/129 resistance, although more common than previously suspected, is concluded not to be plasmid mediated in the strains tested in this study.
Animals↗
Selected cryopreservatives for long term storage of Helicobacter pylori at low temperatures.
To meet the need for information on cryopreservation, a study was done on 32 Helicobacter pylori strains, comparing different cryopreservative media. Sheep blood, horse blood, horse serum with and without glycerol, and mineral oil media were used for long term storage of H pylori at -70 degrees C or in liquid nitrogen. Procedures were developed which permitted recovery of 87.5% of the strains included in the study after they had been stored for 24 months. Of those strains stored for more than three years, 60% were recovered. It is concluded that most strains of H pylori can be stored for up to one year or longer, under refrigeration, at -70 degrees C or in liquid nitrogen.
Cryopreservation↗
Sequential culturing method improves recovery of Legionella spp. from contaminated environmental samples.
Investigations were undertaken to improve detection and isolation of Legionella spp. from samples containing a large number of non-legionellae isolates. The direct fluorescent antibody staining technique was used in conjunction with a sequential culturing method which was developed to improve the recovery rate of Legionella spp. from such samples. The technique for enrichment and isolation of Legionella spp. from environmental samples includes storage at 4 degrees C and repeated culture on freshly prepared media. Heat and acid treatments were included when deemed appropriate. A DNA probe was used for confirmation of Legionella. Treatment of the water samples, as described, and co-cultivation with amoebae naturally present in the samples are concluded to be responsible for increased success in recovery of Legionella isolates.
Air Conditioning↗
Risk assessment in environmental biotechnology.
Scientists in academia and industry concur that appropriate oversight and regulation for biotechnology are in the best interests of society. Field trials have not resulted in any uncontrolled hazard. Oversight should continue and useful methods for assessing risk associated with release of genetically engineered organisms to the environment have been proposed.
Animals↗