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1.
Eye (Lond) ; 35(5): 1418-1426, 2021 May.
Article in English | MEDLINE | ID: mdl-32555545

ABSTRACT

BACKGROUND/AIMS: Optic nerve sheath fenestration (ONSF) is a surgical intervention in the management of idiopathic intracranial hypertension (IIH) infrequently performed in the United Kingdom. Numerous surgical approaches have been described, including medial transconjunctival, lateral and endoscopic. We describe our outcomes and complications from ONSF via a supero-medial eyelid skin crease incision in patients with IIH. METHODS: We performed a retrospective review of consecutive patients undergoing ONSF for IIH between January 2011 and December 2017 by a single surgeon. RESULTS: Thirty patients were included in the analysis with a median follow-up of 14.5 months. Bilateral ONSFs were undertaken in 27 (90%). The data from one eye per patient were analysed. The mean kinetic perimetry score in mean radial degrees of the I4e isopter improved from 27.3° to 35.7°, p = 0.04. After removing cases with optic atrophy, the median modified Frisén grade of papilloedema improved from 2.5 to 1.0, p = 0.007. A total of 5/30 (17%) patients had complications: two (7%) had recurrence/late failure (one managed medically and one with cerebrospinal fluid [CSF] diversion surgery), one had transient cotton wool spots post-operatively, one had transient retinal haemorrhages and one patient had a transiently oval pupil. No patients had repeat ONSF, but CSF diversion surgery was subsequently carried out in 4/30 (13%) patients. CONCLUSIONS: ONSF via a supero-medial eyelid skin crease approach is effective at improving visual function in patients with IIH. The complication rates are low when compared with CSF diversion surgery and other surgical approaches for ONSF.


Subject(s)
Pseudotumor Cerebri , Decompression, Surgical , Eyelids/surgery , Humans , Optic Nerve/surgery , Pseudotumor Cerebri/surgery , Retrospective Studies , United Kingdom
2.
Neuroophthalmology ; 40(2): 59-68, 2016 Apr.
Article in English | MEDLINE | ID: mdl-27928387

ABSTRACT

Sarcoidosis can affect the optic nerves by means of optic disc oedema secondary to posterior uveitis, optic disc oedema secondary to raised intracranial pressure, optic neuritis, optic atrophy secondary to compression or infiltration from a primary central nervous system lesion, and primary granuloma of the optic nerve head. The authors report the use of optical coherence tomography in assessing the response to immunosuppression in a 57-year-old woman with an optic nerve head granuloma.

3.
Neuroophthalmology ; 38(6): 310-319, 2014.
Article in English | MEDLINE | ID: mdl-27928318

ABSTRACT

A retrospective notes review was conducted for 50 consecutive patients who underwent shunt surgery for idiopathic intracranial hypertension (IIH). The decimal visual acuity and the mean radial degrees (MRD) of the I4e isopter of the Goldmann visual field were measured pre-operatively and after a mean follow-up period of 1123 days (range: 13-3551 days). A ventriculo-peritoneal shunt was the first procedure in 38 patients and a lumbo-peritoneal shunt in 12. The mean decimal visual acuity of the worse affected eye improved from 0.75 to 0.84, p = 0.011. The MRD score of the worse affected eye improved on average from 25.6° to 35.5°, p < 0.0001. In those with significant pre-operative visual impairment in their worse affected eye (defined as an MRD score ≤30°), the MRD score improved on average from 10.3° to 26.5°, p = 0.0008. The mean number of surgical procedures for each patient was 2.8 (range: 1-15). Taking all surgical procedures into account, post-operative complications were experienced by 30 patients. At last follow-up, 28 patients still complained of headache, 8 of whom had the intervention performed primarily for headache. Shunting can improve visual function in patients with IIH. There is significant post-operative morbidity and often the need for repeated procedures. Headache also commonly remains in these patients. There is a need for a randomised controlled trial of operative interventions in IIH. Sample size calculations for such a trial to treat significant vision loss are presented.

4.
Neuroophthalmology ; 37(4): 146-156, 2013.
Article in English | MEDLINE | ID: mdl-28167978

ABSTRACT

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) can lead to prominent nerve hypertrophy, which can mimic other forms of neuropathy radiologically. Neuro-ophthalmological complications can also occur in CIDP, either at presentation or chronically in the disorder. This can also cause diagnostic difficulties. We report three cases of neuro-ophthalmological complications of CIDP: two cases of papilloedema and one case of proptosis. In all three cases cranial nerve hypertrophy was present. CIDP should be considered in neuro-ophthalmological presentations associated with cranial/spinal nerve root hypertrophy.

5.
J Appl Microbiol ; 113(3): 569-77, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22738811

ABSTRACT

AIM: This study evaluates the effect of surface application of dried Class A biosolids on microbial populations within copper mine tailings. METHODS AND RESULTS: Mine tailing sites were established at ASARCO Mission Mine close to Sahuarita Arizona. Site 1 (December 1998) was amended with 248 tons ha(-1) of Class A biosolids. Sites 2 (December 2000) and 3 (April 2006) were amended with 371 and 270 tons ha(-1), respectively. Site D, a neighbouring native desert soil, acted as a control for the evaluation of soil microbial characteristics. Surface amendment of Class A biosolids showed a 4 log(10) increase in heterotrophic plate counts (HPCs) compared to unamended tailings, with the increase being maintained for 10-year period. Microbial activities such as nitrification, sulphur oxidation and dehydrogenase activity were also sustained throughout the study period. 16S rRNA clone libraries obtained from community DNA suggest that mine tailings amended with biosolids achieve diversity and bacterial populations similar to native soil bacterial phyla, 10 years postapplication. CONCLUSION: Addition of Class A biosolids to copper mine tailings in the desert south-west increased soil microbial numbers, activity and diversity relative to unamended mine tailings. SIGNIFICANCE AND IMPACT OF THE STUDY: The amended tailings resulted in a functional soil with respect to microbial characteristics, which were sustainable over a 10-year period enabling the development of appropriate vegetation.


Subject(s)
Bacteria/growth & development , Mining , Sewage/microbiology , Soil Microbiology , Soil Pollutants/analysis , Arizona , Bacteria/classification , Biodiversity , Copper , DNA, Bacterial/genetics , Environmental Restoration and Remediation , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Time
6.
Eur J Neurol ; 18(10): 1266-8, 2011 Oct.
Article in English | MEDLINE | ID: mdl-21426442

ABSTRACT

BACKGROUND AND PURPOSE: The purpose of this study was to identify the incidence and prevalence of idiopathic intracranial hypertension (IIH) in Sheffield, UK. METHODS: A retrospective review of case notes was conducted to identify cases of IIH seen between 1 January 2007 and 31 December 2008. RESULTS: Sixteen (15 women and 1 man) new patients were identified to give an incidence within Sheffield of 1.56/100,000/year and 2.86/100,000/year for women. The incidence of IIH in obese women was 11.9/100,000/year. The prevalence of IIH was calculated as 10.9/100,000, and 85.7/100,000 in obese women. CONCLUSION: A higher incidence of IIH than previously reported UK data was found, which may be because of increasing obesity within the population, or improved case ascertainment.


Subject(s)
Obesity/epidemiology , Pseudotumor Cerebri/diagnosis , Pseudotumor Cerebri/epidemiology , Adult , Comorbidity , Female , Humans , Incidence , Male , Obesity/diagnosis , Prevalence , Retrospective Studies , United Kingdom/epidemiology , Young Adult
8.
J Appl Microbiol ; 109(2): 698-706, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20202022

ABSTRACT

AIM: To evaluate the effect of long-term annual land applications of Class B biosolids on soil bacterial diversity at University of Arizona Marana Agricultural Field Center, Tucson, Arizona. METHODS AND RESULTS: Following the final of 20 consecutive years of application of Class B biosolids in March 2005, followed by cotton growth from April to November 2005 surface soil samples (0-30 cm) were collected from control (unamended) and biosolid-amended plots. Total bacterial community DNA was extracted, amplified using 16S rRNA primers, cloned, and sequenced. All 16S rRNA sequences were identified by 16S rRNA sequence analysis and comparison to known sequences in GenBank (NCBI BlastN and Ribosomal Database Project II, RDP). Results showed that the number of known genera (identifiable > 96%) increased in the high rate biosolid plots compared to control plots. Biosolids-amended soils had a broad phylogenetic diversity comprising more than four major phyla: Proteobacteria (32%), Acidobacteria (21%), Actinobacteria (16%), Firmicutes (7%), and Bacteroidetes (6%) which were typical to bacterial diversity found in the unamended arid southwestern soils. CONCLUSION: Bacterial diversity was either enhanced or was not negatively impacted following 20 years of land application of Class B biosolids. SIGNIFICANCE AND IMPACT OF THE STUDY: This study illustrates that long-term land application of biosolids to arid southwestern desert soils has no deleterious effect on soil microbial diversity.


Subject(s)
Bacteria/classification , Sewage , Soil Microbiology , Actinobacteria/genetics , Actinobacteria/isolation & purification , Arizona , Bacteria/genetics , Bacteria/isolation & purification , Biodiversity , Proteobacteria/genetics , Proteobacteria/isolation & purification , RNA, Ribosomal, 16S/genetics , Sewage/adverse effects
9.
J Appl Microbiol ; 103(5): 1779-90, 2007 Nov.
Article in English | MEDLINE | ID: mdl-17953588

ABSTRACT

AIMS: The purpose of this study was to determine the diversity of bacterial communities associated with bioaerosols generated during land application of biosolids using 16S ribosomal RNA (16S rRNA) PCR. METHODS AND RESULTS: Anaerobically digested Class B biosolids were land applied to an agricultural site located in South Central Arizona. Aerosol samples were collected downwind of the biosolids operations and were collected via the use of SKC Biosamplers and subsequently extracted for the presence of bacterial community DNA. All DNA was amplified using 16S rRNA primers, cloned and sequenced. All sequences were aligned and phylogenetic trees were developed to generate community profiles. The majority of aerosolized bacterial clone sequences belonged to the Actinobacteria and alpha- and beta-proteobacterial taxa. Aerosol samples collected downwind of soil aerosolization produced similar profiles. These profiles differed from upwind and background samples. CONCLUSIONS: No one clone sequence isolated from the aerosol samples could be solely attributed to biosolids; on the contrary, the majority appeared to have arisen from soil. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates that in dry, arid climates the majority of aerosols associated with biosolids land application appear to be associated with the onsite soil.


Subject(s)
Agriculture , Air Microbiology , Bacteria/isolation & purification , Environmental Monitoring/methods , Sewage , Actinobacteria/genetics , Actinobacteria/isolation & purification , Aerosols , Bacteria/genetics , Environmental Monitoring/instrumentation , Genes, Bacterial , Phylogeny , Polymerase Chain Reaction/methods , Proteobacteria/genetics , Proteobacteria/isolation & purification , RNA, Ribosomal, 16S/analysis , Soil Microbiology , Wind
10.
Can J Microbiol ; 53(5): 616-22, 2007 May.
Article in English | MEDLINE | ID: mdl-17668020

ABSTRACT

The purpose of this study was to determine the prevalence of antibiotic-resistant bacteria and endotoxin in soil after land application of biosolids. Soil was collected over a 15 month period following land application of biosolids, and antibiotic resistance was ascertained using clinically relevant antibiotic concentrations. Ampicillin, cephalothin, ciprofloxacin, and tetracycline resistance were all monitored separately for any changes throughout the 15 month period. Endotoxin soil concentrations were monitored using commercially available endotoxin analysis reagents. Overall, land application of biosolids did not increase the percentage of antibiotic-resistant culturable bacteria above background soil levels. Likewise, land application of biosolids did not significantly increase the concentration of endotoxin in soil. This study determined and established a baseline understanding of the overall effect that land application of biosolids had on the land-applied field with respect to antibiotic-resistant bacterial and endotoxin soil densities.


Subject(s)
Bacteria/metabolism , Drug Resistance, Multiple, Bacterial , Endotoxins/analysis , Particulate Matter/chemistry , Anti-Bacterial Agents/pharmacology , Bacteria/genetics , Bacteria/isolation & purification , Environmental Monitoring/methods , Refuse Disposal , Soil/analysis
11.
Appl Microbiol Biotechnol ; 73(3): 691-5, 2006 Dec.
Article in English | MEDLINE | ID: mdl-16802151

ABSTRACT

Gentisate-1,2-dioxygenase genes (gdoA), with homology to a number of bacterial dioxygenases, and genes encoding a putative coenzyme A (CoA)-synthetase subunit (acdB) and a CoA-thioesterase (tieA) were identified in two haloarchaeal isolates. In Haloarcula sp. D1, gdoA was expressed during growth on 4-hydroxybenzoate but not benzoate, and acdB and tieA were not expressed during growth on any of the aromatic substrates tested. In contrast, gdoA was expressed in Haloferax sp. D1227 during growth on benzoate, 3-hydroxybenzoate, cinnamate and phenylpropionate, and both acdB and tieA were expressed during growth on benzoate, cinnamate and phenylpropionate, but not on 3-hydroxybenzoate. This pattern of induction is consistent with these genes encoding steps in a CoA-mediated benzoate pathway in this strain.


Subject(s)
Dioxygenases/genetics , Genes, Archaeal , Haloarcula/genetics , Haloferax/genetics , Benzoates/metabolism , Cloning, Molecular , DNA, Archaeal/genetics , Gene Expression Profiling , Haloarcula/enzymology , Haloferax/enzymology , Molecular Sequence Data , Sequence Alignment
12.
Can J Microbiol ; 52(2): 150-6, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16541151

ABSTRACT

The purpose of this study was to determine aerosolized endotoxin concentrations downwind of a biosolids land application site. Aerosol samples were collected from biosolids land application sites, tractor operation, and an aeration basin located within an open-air wastewater treatment plant. Aerosolized endotoxin above background concentrations was detected from all sites, at levels ranging from below detection up to 1800 EU m-3 of air. Biosolids loading operations resulted in the greatest concentrations of endotoxin (mean 344 EU m-3). As downwind (perpendicular to wind vector) distance increased from sources (2-200 m), levels of endotoxin decreased to near background (without biosolids application) concentrations. Overall, the detected levels of aerosolized endotoxin were within past proposed aerosolized endotoxin limits (250-2000 EU m-3) by other occupational exposure studies. Occasionally, peak concentrations were found to be above these limits. Sites in which soil was being aerosolized resulted in greater concentrations of endotoxin with or without biosolids, which suggested that the majority of endotoxin may in fact be of soil origin. This study evaluated the presence of aerosolized endotoxin from the land application of biosolids and showed that these levels were within ranges for concern suggested by other studies and that this area of research needs further investigation.


Subject(s)
Air Pollutants/analysis , Endotoxins/analysis , Refuse Disposal , Aerosols , Arizona , Environmental Monitoring/methods
13.
J Appl Microbiol ; 99(2): 310-22, 2005.
Article in English | MEDLINE | ID: mdl-16033462

ABSTRACT

AIMS: The purpose of this study was to evaluate the community risk of infection from bioaerosols to residents living near biosolids land application sites. METHODS AND RESULTS: Approximately 350 aerosol samples from 10 sites located throughout the USA were collected via the use of six SKC Biosamplers. Downwind aerosol samples from biosolids loading, unloading, land application and background operations were collected from all sites. All samples were analysed for the presence of HPC bacteria, total coliform bacteria, Escherichia coli, Clostridium perfringens, coliphage, enteroviruses, hepatitis A virus and norovirus. Total coliforms, E. coli, C. perfringens and coliphage were not detected with great frequency from any sites, however, biosolids loading operations resulted in the largest concentrations of these aerosolized microbial indicators. Microbial risk analyses were conducted on loading and land application operations and their subsequent residential exposures determined. CONCLUSIONS: The greatest annual risks of infection occurred during loading operations, and resulted in a 4 x 10(-4) chance of infection from inhalation of coxsackievirus A21. Land application of biosolids resulted in risks that were <2 x 10(-4) from inhalation of coxsackievirus A21. Overall bioaerosol exposure from biosolids operations poses little community risk based on this study. SIGNIFICANCE AND IMPACT OF THE STUDY: This study evaluated the overall incidence of aerosolized micro-organisms from the land application of biosolids and subsequently determined that microbial risks of infection were low for residents close to biosolids application sites.


Subject(s)
Aerosols/adverse effects , Air Pollutants/adverse effects , Communicable Diseases/microbiology , Air Microbiology , Bacteria/isolation & purification , Clostridium perfringens/isolation & purification , Coliphages/isolation & purification , Colony Count, Microbial/methods , Enterobacteriaceae/isolation & purification , Enterovirus/isolation & purification , Environmental Monitoring/methods , Fertilizers/adverse effects , Hepatitis A virus/isolation & purification , Humans , Reverse Transcriptase Polymerase Chain Reaction/methods , Risk Assessment/methods , Salmonella/isolation & purification , Soil Microbiology , Soil Pollutants/adverse effects , Viruses/isolation & purification
14.
J Appl Microbiol ; 98(2): 397-405, 2005.
Article in English | MEDLINE | ID: mdl-15659194

ABSTRACT

AIM: The purpose of this study was to develop an empirically derived transport model, which could be used to predict downwind concentrations of viruses and bacteria during land application of liquid biosolids and subsequently assess microbial risk associated with this practice. METHODS AND RESULTS: To develop the model, coliphage MS-2 and Escherichia coli were aerosolized after addition to water within a biosolids spray application truck, and bioaerosols were collected at discrete downwind distances ranging from 2 to 70 m. Although coliphage were routinely detected, E. coli did not frequently survive aerosolization. Data on aerosolized coliphage was then used to generate a virus transport model. Risks of infection were calculated for various ranges of human virus concentrations that could be found in biosolids. CONCLUSIONS: A conservative estimate at 30.5 m (assumed to be nearest adjacent residences) downwind, resulted in risks of infection of 1 : 100,000, to the more realistic 1 : 10,000,000 per exposure. Conservative annual risks were calculated to be no more than 7 : 100,000 where as a more realistic risk was no greater than 7 : 10,000,000. Overall, the viral risk to residences adjacent to land application sites appears to be low, both for one time and annual probabilities of infection. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrated a simple approach towards modelling viral pathogens aerosolized from land applied liquid biosolids, and offers insight into the associated viral risk.


Subject(s)
Agriculture , Air Microbiology , Air Pollution , Sewage , Bacteria , Humans , Risk Assessment , Viruses , Wind
15.
Eye (Lond) ; 19(1): 55-9, 2005 Jan.
Article in English | MEDLINE | ID: mdl-15184957

ABSTRACT

AIMS: 1. To assess the prevalence of visual impairment in those patients who sustain proximal hip fracture after a simple fall. 2. To test the validity of a simple screening test to identify patients with visual impairment. METHODS: Patients on the orthopaedic rehabilitation ward recuperating from proximal hip fracture were recruited. The nurse screener and examining Ophthalmologist independently assessed the patients' distance visual acuity and visual field to confrontation. In addition, the nurse screener assessed for the presence of cataract in the red reflex and the examining Ophthalmologist performed a dilated slit-lamp examination. On completion of the examination, the Ophthalmologist documented the cause(s) of any visual impairment found. RESULTS: A total of 89 patients were assessed. In all, 29 patients (33%) could be classified as visually impaired using the United States criteria and 52 patients (58%) had a distance visual acuity of 6/18 or worse in at least one eye. The test reliably identified those patients with visual impairment (sensitivity 94% (+/-5%), specificity 92% (+/-6%)), but was less reliable at identifying those patients with potentially remedial visual impairment (sensitivity 70% (+/-10%), specificity 92% (+/-6%)). CONCLUSION: The level of visual impairment in this group of patients is high and screening for visual impairment in the elderly with a history of falls is justified. We have demonstrated that a suitably trained member of the rehabilitation team can identify over 94% of those patients with impaired vision. We believe this simple test should now be incorporated into the assessment of all patients requiring rehabilitation after a proximal hip fracture.


Subject(s)
Hip Fractures/complications , Vision Disorders/diagnosis , Aged , Aged, 80 and over , Cataract/complications , Cataract/diagnosis , Cataract/physiopathology , Cohort Studies , Female , Humans , Likelihood Functions , Male , Nursing Care/methods , Sensitivity and Specificity , Vision Disorders/complications , Vision Disorders/physiopathology , Visual Acuity/physiology
16.
Water Sci Technol ; 50(1): 7-12, 2004.
Article in English | MEDLINE | ID: mdl-15318479

ABSTRACT

This study evaluated bioaerosol emissions during land application of Class B biosolids in and around Tucson, Arizona, to aid in developing models of the fate and transport of bioaerosols generated from the land application of biosolids. Samples were collected for 20 min at distances between 2 m and 20 m downwind of point sources, using an SKC BioSampler impinger. A total of six samples were collected per sampling event, which consisted of a biosolid spray applicator applying liquid biosolids to a cotton field. Each application represented one exposure. Samples were collected in deionised water amended with peptone and antifoam agent. Ambient weather conditions were also monitored every 10 min following initiation of sampling. Concurrently with downwind samples, background (ambient) air samples were collected to compensate for any ambient airborne microorganisms. In addition, biosolids samples were collected for analysis of target indicator and pathogenic organisms. Soil samples were also collected and analysed. Significant numbers of heterotrophic plate count (HPC) bacteria were found in air samples collected during the biosolid application process. These could have arisen from soil particles being aerosolised during the land application process. Aerosolised soil may contribute significantly to the amount of aerosolised microorganisms. Soil particles may be able to more readily aerosolise, due to their low density, small particle size and low mass. Aerosolised HPC bacteria found during biosolids land application were similar to those found during normal tractor operation on non-biosolids applied fields. Coliforms and coliphages were not routinely detected even though they were found to be present in the biosolids at relatively high concentrations, 10(6) and 10(4)/g (dry weight) of biosolids respectively. This could be due to the die-off rate of aerosolised Gram-negative bacteria or sorption to the solid portion of the biosolids. Low numbers of aerosolised coliphages may likewise be due to sorption phenomena. We theorise that only organisms in the aqueous phase of the biosolids were available to desorb and be aerosolised. Animal viruses, which were not detected in the biosolids, were likewise not detected in the aerosol samples. Clostridium perfringens was detected in only a small percent of aerosol samples although it was detected during all weather conditions; other microorganisms were detected during more favourable environmental conditions (relative humidity >10%). Despite the fact that many of these organisms were present in the biosolids at significant concentrations, their presence in bioaerosols generated during the land application of biosolids was limited to only a small percentage of samples. Bacteria as well as viruses may sorb to biosolids, which contain a high percentage of organic matter, and desorption during land application of biosolids may not readily take place; therefore, these microorganisms may not be readily aerosolised.


Subject(s)
Aerosols/analysis , Waste Disposal, Fluid , Adsorption , Bacteria/isolation & purification , Desert Climate , Environmental Monitoring , Soil , United States , Viruses/isolation & purification
17.
Int J Food Microbiol ; 92(3): 289-95, 2004 May 01.
Article in English | MEDLINE | ID: mdl-15145587

ABSTRACT

The goal of this project was to quantify the concentration of heterotrophic plate count (HPC) bacteria within water reaching consumer's taps, and from the sources used by a major utility serving the City of Tucson, AZ. With this information, the amounts and sources of HPC bacteria consumed at the tap could be determined. Samples of water were collected on a monthly basis from two well fields, the CAVSARP recovery well field and Southern Avra Valley well field which serves as one of the groundwater sources for Tucson, AZ, and the distribution system which serves the same homes from which tap water was also tested. The average concentration of HPC in source waters within Southern Avra Valley Wells was 56 CFU/ml (range 1-1995/ml). From the CAVSARP recovery well field, corresponding values were 38 CFU/ml (1 to 502 CFU/ml). Unblended groundwater in the chlorinated distribution system averaged 22 CFU/ml (range 1-794). Blended water at the chlorinated distribution site averaged 47 CFU/ml (range 10-158). There was a major shift in the percentage of gram negative to gram-positive bacteria from the wells to the distribution system, to the tap. In the surface CAP source water, 76% of the bacteria were gram-negative compared to 27% gram-negative in the CAVSARP recovery wells. In contrast, Avra Valley wells contained 17% gram-negative bacteria. In both the Tucson groundwater distribution sites and blended distribution sites, the corresponding number of gram negative bacteria was 12%. Finally at the tap, only 0.2% of the bacteria were gram-negative. The average number of bacteria in household taps averaged 3072 HPC/ml and was equal or greater than 500 ml 68% of the time. This study shows that the number of HPC bacteria increases dramatically from the distribution system to the consumers tap. Thus, the major source of bacteria ingested by the average consumer in Tucson originates from bacteria within the household distribution system or the household tap, rather than from source waters or the distribution system. It is also clear that consumers' regularly consume more than 500 HPC/ml from drinking water taken from the household tap.


Subject(s)
Bacteria/isolation & purification , Water Microbiology , Water Supply , Arizona , Bacteria/drug effects , Bacteria/growth & development , Chlorine/pharmacology , Colony Count, Microbial , Consumer Product Safety , Gram-Negative Bacteria/growth & development , Gram-Negative Bacteria/isolation & purification , Gram-Positive Bacteria/growth & development , Gram-Positive Bacteria/isolation & purification , Humans , Quality Control , Water Purification , Water Supply/analysis , Water Supply/standards
18.
Microb Ecol ; 48(1): 90-102, 2004 Jul.
Article in English | MEDLINE | ID: mdl-15085300

ABSTRACT

A study was conducted to determine the diversity of 2-, 3-, and 4-chlorobenzoate (CB) degraders in two pristine soils with similar physical and chemical characteristics. Surface soils were collected from forested sites and amended with 500 microg of 2-, 3-, or 4-CB g(-1) soil. The CB levels and degrader numbers were monitored throughout the study. Degraders were isolated, grouped by DNA fingerprints, identified via 16S rDNA sequences, and screened for plasmids. The CB genes in selected degraders were isolated and/or sequenced. In the Madera soil, 2-CB and 4-CB degraded within 11 and 42 d, respectively, but 3-CB did not degrade. In contrast, 3-CB and 4-CB degraded in the Oversite soil within 14 and 28 d, respectively, while 2-CB did not degrade. Approximately 10(7) CFU g(-1) of degraders were detected in the Madera soil with 2-CB, and the Oversite soil with 3- and 4-CB. No degraders were detected in the Madera soil with 4-CB even though the 4-CB degraded. Nearly all of the 2-CB degraders isolated from the Madera soil were identified as a Burkholderia sp. containing chromosomally encoded degradative genes. In contrast, several different 3- and 4-CB degraders were isolated from the Oversite soil, and their populations changed as CB degradation progressed. Most of these 3-CB degraders were identified as Burkholderia spp. while the majority of 4-CB degraders were identified as Bradyrhizobium spp. Several of the 3-CB degraders contained the degradative genes on large plasmids, and there was variation between the plasmids in different isolates. When a fresh sample of Madera soil was amended with 50, 100, or 200 microg 3-CB g(-1), 3-CB degradation occurred, suggesting that 500 microg 3-CB g(-1) was toxic to the degraders. Also, different 3-CB degraders were isolated from the Madera soil at each of the three lower levels of 3-CB. No 2-CB degradation was detected in the Oversite soil even at lower 2-CB levels. These results indicate that the development of 2-, 3-, and 4-CB degrader populations is site-specific and that 2-, 3-, and 4-CB are degraded by different bacterial populations in pristine soils. These results also imply that the microbial ecology of two soils that develop under similar biotic and abiotic environments can be quite different.


Subject(s)
Bacteria/metabolism , Chlorobenzoates/metabolism , Ecosystem , Phylogeny , Soil Microbiology , Arizona , Bacteria/genetics , Base Sequence , Biodegradation, Environmental , Blotting, Southern , Cluster Analysis , DNA Fingerprinting , DNA Primers , Molecular Sequence Data , Plasmids/genetics , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA
20.
Water Sci Technol ; 46(10): 225-30, 2002.
Article in English | MEDLINE | ID: mdl-12479475

ABSTRACT

Since the development of the United States Environmental Protection Agency's 503 biosolids Rule, which includes treatment requirements to reduce the threat of pathogen transmission, many new pathogens have been recognized which could be transmitted by biosolids. A risk analysis was performed assess which emerging pathogens would be most likely to survive treatments required for Class B biosolids before land application. The literature was reviewed on the resistance of emerging pathogens to temperature and other environmental factors to assess their probability of surviving various biosolids treatment processes. In addition existing information on occurrence in biosolids and dose response models for each pathogen was reviewed. It was concluded that adenoviruses and hepatitis A virus are the most thermally resistant viruses and can survive for prolonged periods in the environment. The protozoan parasites microsporidia and Cyclospora were unlikely to survive the temperatures achieved in anaerobic digestion and do not survive well under low moisture conditions. A risk model was used to assess the risk of infection and illness from enteric viruses after application of class B biosolids.


Subject(s)
Bioreactors , Cyclospora/isolation & purification , Models, Theoretical , Sewage/microbiology , Adenoviridae/isolation & purification , Bacteria, Anaerobic/physiology , Cyclospora/pathogenicity , Hepatitis A virus/isolation & purification , Risk Assessment , Sewage/chemistry , Survival , Temperature
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