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PubMed2006

Average intensity and spreading of an elliptical gaussian beam propagating in a turbulent atmosphere.

An analytical formula for the average intensity of an elliptical Gaussian beam (EGB) propagating in a turbulent atmosphere is derived. The spreading properties of an EGB in a turbulent atmosphere are studied. It is found that an EGB will eventually become a circular Gaussian beam in a turbulent atmosphere. This interesting phenomenon is quite different from the propagation of an EGB in free space. The evolution properties are closely related to the parameters of the beam and the turbulent atmosphere.

Journal Article↗
PubMed2004

Acousto-optic differential optical absorption spectroscopy for atmospheric measurement of nitrogen dioxide in Hong Kong.

Measurement of the atmospheric concentration of nitrogen dioxide (NO(2)) pollutant was demonstrated by differential optical absorption spectroscopy (DOAS) using a visible acousto-optic tunable filter. In a traditional spectral scanning DOAS system for atmospheric concentration monitoring, a highly stable light source is required. When the light intensity fluctuates during scanning, the concentration retrieval will be inaccurate. In order to reduce the error due to intensity fluctuations, a modified DOAS system has been developed by introducing a broadband light intensity monitoring channel. Using the measured intensity of the broadband channel as the intensity of the light source, the spectrum can be de-biased and the residual intensity variation will primarily result from atmospheric extinction. In addition, by employing the lock-in detection technique, the background light interference is also removed in the modified DOAS system. The atmospheric NO(2) concentration measurement was performed at the campus of City University of Hong Kong, and the results were compared with the concentration reported from a nearby monitoring station in Sham Shui Po, operated by the Hong Kong Environmental Protection Department.

Absorption↗
PubMed2004

Ionizing irradiation quarantine treatment against oriental fruit moth (Lepidoptera: Tortricidae) in ambient and hypoxic atmospheres.

Oriental fruit moth, Grapholita molesta (Busck), is a pest of many rosaceous temperate fruits, including pomes, Malus spp., and stone fruits, Prunus spp., in much of the world. However, some areas are free of the pest, and shipments of fruit hosts from infested to noninfested areas may be regulated. Current quarantine treatments for oriental fruit moth include methyl bromide fumigation and cold storage for several weeks. Methyl bromide use is being restricted because it is a stratospheric ozone-depleting substance, and alternatives are sought. Cold is not tolerated by many hosts of oriental fruit moth. The objective of this research was to develop irradiation quarantine treatments against the pest under ambient and hypoxic storage conditions because some hosts of oriental fruit moth are stored in hypoxic atmospheres, and hypoxia is known to lessen the effects of irradiation. In ambient atmospheres, no adults emerged from 58,779 fifth instars (the most radiotolerant stage present in fruit) irradiated with a target dose of 200 Gy (195-232 Gy measured). In atmospheres flushed with nitrogen, 5.3% of adults emerged from 44,050 fifth instars irradiated with a target dose of 200 Gy (194-230 Gy measured), but they died at a faster rate than control adults and without laying eggs. A dose of 232 Gy (the maximum recorded when 200 Gy was targeted) is recommended to disinfest any fruit of oriental fruit moth under ambient and hypoxic atmospheres.

Animals↗
PubMed2005

Determination of total gaseous lead in the atmosphere by honeycomb denuder/electrothermal atomic absorption spectrometry.

A technique is described for the determination of total gaseous lead in the atmosphere by honeycomb denuder collection, followed by an electrothermal atomic absorption spectrometry (ETAAS) measurement. The collection efficiency of the honeycomb denuder in which a solution containing 2% HNO3/2% glycerine/1% ammonium dihydrogenphosphate was coated for trapping the gaseous lead in the atmosphere was 98.8%. The linear absorbance response was obtained for a concentration range of 0-1.39 microg m(-3) of lead in the atmosphere. A precision of 4.8% RSD (peak-height absorbance, n = 11) for an aqueous solution of 1 ng of lead standard, characteristic masses (CM) of 23 pg and detection limit (3sigma) of 54 pg for an aqueous solution of 0.01 ng lead standard was achieved with 100 microg ammonium dihydrogenphosphate as a chemical modifier. The average recovery of lead in three standard samples prepared by the independent digestion of NIST SRM 1648 (Urban Particulate Matter) using our analytical system was 97.8%. The total content of the gaseous lead in the atmosphere of our laboratories was 0.35-0.38 microg m(-3).

Air Pollutants↗
PubMed2006

Simultaneous monitoring method of polycyclic aromatic hydrocarbons and persistent organic pollutants in the atmosphere using activated carbon fiber filter paper.

In order to simultaneously monitor the concentrations of PAHs and POPs in the atmosphere, an activated carbon fiber filter paper (ACFP) was used as the adsorbing material in this study. The pressurized liquid extraction method (PLE method) was used to extract PAHs and POPs collected on the ACFP. Toluene was an effective solvent to extract them from ACFP using the PLE method, but some of PAHs, such as benzo(a)pyrene, benzo(g,h,i)perylene, dibenzo(a,h)anthracene and indeno(1,2,3-cd)pyrene, were hardly extracted. These PAHs were adsorbed on the particulate matter in the atmosphere. In general, these forms of particulate matter could be collected using a quartz fiber paper (QFP); these PAHs were efficiently extracted from the QFP using the PLE method with toluene. In this study, the collecting method of the PAHs was modified by using QFP overlapped in front of the ACFP. Atmospheric monitoring of PAHs and POPs in Niigata area was performed using this method, and most of the target compounds were detected. However, some of the POPs, such as aldrin, endrin, mirex, could not be detected. The POPs, such as hexachlorobenzene, alpha-hexachlorocyclohexane and chlordanes, and most of the PAHs were detected from all of the samples collected throughout the monitoring period. It was confirmed that these methods were effective to simultaneously monitor the concentrations of the PAHs and POPs in the atmosphere.

Journal Article↗
PubMedDate not supplied

Atmospheric movements of lindane (gamma-hexachlorocyclohexane) from canola fields planted with treated seed.

Lindane (gamma-hexachlorocyclohexane [gamma-HCH]) is used as an insecticide in many countries. Concentrations of gamma-HCH have been found in air, water, soil, snow, and tissue samples throughout the world and concerns have been raised for its potential effects on human and ecosystem health. In Canada, gamma-HCH is primarily used as a treatment on canola (Brassica napus L) seed with an estimated 455.3 Mg applied in 1997 and 510.4 Mg in 1998. The purpose of this study was to measure gamma-HCH volatilization from fields planted with treated canola seed. Atmospheric dry and wet deposition and soil samples were collected for two growing seasons (1997 and 1998) from a canola field planted with treated seed. Atmospheric concentrations as high as 16.1 and 7.4 ng m(-3) were measured at 1 m above the canola field compared with maximum concentrations of 2.9 and 2.7 ng m(-3) measured above a grass field located 2 km away (1997 and 1998, respectively). On the basis of measurements made in this study it was estimated that between 12 and 30% of the gamma-HCH applied as canola seed treatment may volatilize and be released to the atmosphere. This would create an atmospheric loading of 66.4 to 188.8 Mg for the 6-wk period following planting, estimated from the quantity of seed sown on the Canadian prairies in 1998. Dry deposition rates and rain concentrations as high as 2,203 ng m(-2) d(-1) and 170 ng L(-1) were measured adjacent to the canola field.

Agriculture↗
PubMed2006

Sorption of atmospheric ammonia by soil and perennial grass downwind from two large cattle feedlots.

Livestock manure in feedlots releases ammonia (NH3), which can be sorbed by nearby soil and plants. Ammonia sorption by soil and its effects on soil and perennial grass N contents downwind from two large cattle feedlots in Alberta, Canada were investigated from June to October 2002. Atmospheric NH3 sorption was measured weekly by exposing air-dried soil at sampling points downwind along 1700-m transects. The amount of NH3 sorbed by soil was 2.60 to 3.16 kg N ha(-1) wk(-1) near the source, declining to about 0.25 kg N ha(-1) wk(-1) 1700 m downwind, reflecting diminishing atmospheric NH3 concentrations. Ammonia sorption at a control site away from NH3 sources was much lower: 0.085 kg N ha(-1) wk(-1). Based on these rates, about 19% of emitted NH3 is sorbed by soil within 1700 m downwind of feedlots. Field soil and grass samples from the transect lines were analyzed for total N (TN) and KCl-extractable N content (soil only). Nitrate N content in field soil followed a trend similar to that of atmospheric NH3 sorption. Soil TN contents, because of high background levels, showed no clear pattern. The TN content of grass, downwind of the newer feedlot, followed a pattern similar to that of NH3 sorption; downwind of the older feedlot, grass TN was correlated to soil TN. Our results suggest that atmospheric NH3 from livestock operations can contribute N to local soil and vegetation, and may need to be considered when determining fertilizer rates and assessing environmental impact.

Air Pollutants↗
PubMed1998

Specific inhibition of Photobacterium phosphoreum extends the shelf life of modified-atmosphere-packed cod fillets.

Inhibition of the specific spoilage organism, Photobacterium phosphoreum, was studied in model substrates and in modified-atmosphere-packed cod fillets. The objective was to determine how inhibition of this organism influenced spoilage. The spoilage reactions limiting shelf life were studied rather than the development of a new product. In naturally contaminated modified-atmosphere-packed cod fillets, 500 ppm Na2CaEDTA reduced the growth rate of P. phosphoreum by 40% and shelf life was increased proportionally by 40%, from 15 to 17 days to 21 to 23 days at 0 degree C. In aerobically stored cod fillets other microorganisms were responsible for spoilage and Na2CaEDTA had no effect on shelf life. The extension of the shelf life of modified-atmosphere-packed cod therefore was a result of the reduced growth of P. phosphoreum and no other microbial or nonmicrobial spoilage reactions limited shelf life. These results confirmed P. phosphoreum as the specific spoilage organism in modified-atmosphere-packed cod and showed the organism to have an extensive spoilage domain. Consequently, any preservation procedure able to reduce growth of P. phosphoreum is likely to extend shelf life of packed cod. However, the effect of different inhibitory compounds in model systems as well as results from packed cod indicated the need to include product studies in the screening of antimicrobials and in the development of preservation procedures.

Aerobiosis↗
PubMed2001

Formation of biogenic amines in bulk-stored chilled hake (Merluccius merluccius L.) packed under atmospheres.

The production of biogenic amines in the lots of whole hake stored bulk under a controlled or modified atmosphere for 12 days with the gas mixture 40% CO2:40% O2:20% N2 and after packing in trays under a modified atmosphere in the same mixture of gases or with air was studied. Results indicated a close relation between the development of trimethylamine nitrogen (TMA-N) and the sensory parameters gill appearance and odor but not with the general appearance of the skin and eyes. These results were related to changes observed in the concentration of gases (CO2 and O2) during storage containers and trays. The lot of bulk-stored whole hake in controlled atmospheres for 12 days with the gas mixture 40% CO2:40% O2:20% N2 and then packed in trays with the same atmosphere exhibited TMA-N levels below the 12.5 mg/100 g limit designated by the legislation in force (Directive 91/143/EU) on day 31 of storage when the sensory parameters general appearance and skin and gill color were not rejected. Histamine and tyramine levels were less than 1 mg/kg, putrescine levels were approximately 7 mg/kg, and cadaverine and agmatine levels were 33.91 and 20.33 mg/100 g, respectively.

Animals↗
PubMed2002

Preservation of shelf life of pota and octopus in chilled storage under controlled atmospheres.

Whole ungutted pota and octopus were stored in bulk in stainless steel refrigerated containers under controlled atmospheres. In order to evaluate the effectiveness of this treatment, physicochemical tests (pH, trimethylamine nitrogen, total volatile basic nitrogen, 2-thiobarbituric acid) and sensory assessments (inspection) were done. For both pota and octopus, the control lot had the highest physicochemical values and the lowest sensory values, and of the two assayed atmospheres, the 60/15/25% atmosphere (CO2/O2/N2) had the best physicochemical results. pH, trimethylamine nitrogen, and total volatile basic nitrogen levels were lower (P < or = 0.05) in octopus than in pota, and the inspection results were significantly (P < or = 0.05) higher. However, the octopus had a higher 2-thiobarbituric acid index than the pota. Therefore, the application of controlled atmospheres on these cephalopods during chilled bulk storage considerably increases their shelf life.

Animals↗
PubMed2005

Role of sulfites and 4-hexylresorcinol in microbial growth and melanosis prevention of deepwater pink shrimp (Parapenaeus longirostris) using a controlled atmosphere.

A controlled atmosphere containing 48% CO2 and 7% O2 was used in association with refrigeration for storage of deepwater pink shrimp (Parapenaeus longirostris). Shrimp were treated with two different concentrations of sodium metabisulfite or 4-hexylresorcinol and subjected to the controlled atmosphere immediately after capture onboard ship or on arrival in port. Total volatile basic nitrogen, total viable counts, enterobacteria, lactic acid bacteria, and luminescent bacteria were determined, and black spot progression was evaluated. The combined effect of controlled atmosphere and melanosis inhibitors was used to delay black spot development as compared to the shrimp stored in ice alone. Storage under the controlled atmosphere without ice limited microbiological quality, namely, total viable counts, but enterobacterial growth was lower.

Animals↗
PubMed2005

Shelf-life extension of refrigerated Mediterranean mullet (Mullus surmuletus) using modified atmosphere packaging.

The present work evaluated the quality and freshness characteristics and the effect of modified atmosphere packaging (MAP) on the shelf-life extension of refrigerated Mediterranean mullet using microbiological, biochemical, and sensory analyses. Fresh open sea red mullet (Mullus surmuletus) were packaged in four different atmospheres: M1, 10%/20%/70% (O2/ CO2/N2); M2, 10%/40%/50% (O2/CO2/N2); M3, 10%/60%/30% (O2/CO2/N2); identical fish samples were packaged in air. All fish were kept under refrigeration (4 +/- 0.5 degrees C) for 14 days. Of the three gas atmospheres, the 10%/40%/50% (M2) and 10%/ 60%/30% (M3) gas mixtures were the most effective for inhibiting growth of aerobic microflora in mullet samples until day 10 of refrigerated storage. H2S-producing bacteria and pseudomonads were part of the mullet microflora and their growth was partly inhibited under MAP conditions. Between these two bacterial groups, H2S-producing bacteria (including Shewanella putrefaciens) were dominant toward the end of the storage period, regardless of the packaging conditions. Brochothrix thermosphacta and lactic acid bacteria were found to be members of the final microbial flora of MAP and air-packaged mullet, whereas the Enterobacteriaceae population was lower than other bacterial groups. Of the chemical freshness indices determined, thiobarbituric acid values were variable in mullet samples irrespective of packaging conditions indicative of no specific oxidative rancidity trend. Based on sensorial data and aerobic plate count, trimethylamine nitrogen and total volatile basic nitrogen limit values in the range of ca. 15 to 23 and 52 to 60 mg N/100 g of fish muscle were obtained, respectively, for mullet packaged under modified atmosphere and air. Sensory analyses (odor and taste attributes) showed that the limit of sensorial acceptability was reached after ca. 6 days for the samples packaged in air, 8 days for the M1 and M3 samples, and after 10 days for the M2 samples. Respective shelf-life extension for fresh whole mullet was ca. 2 days (M1 and M3 gas mixtures), and 4 days (M2 gas mixture).

Animals↗
PubMed2005

Growth and toxin production by Clostridium botulinum in steamed rice aseptically packed under modified atmosphere.

Sales and consumption of ready-to-eat aseptic steamed rice products have increased manyfold in Japan over the past 10 years. To determine the safety of steamed rice (water content 60%, pH 6.5) aseptically packaged under modified atmosphere, challenge studies were performed using a mixture of Clostridium botulinum proteolytic strains (five strains of type A and five strains of type B). Atmospheric conditions of 0 and 15% oxygen (with 5% CO2 and 5% N2 as the balance) were used. No neurotoxins were detected, and organoleptically acceptable conditions persisted for 24 weeks at 15% oxygen conditions. However, botulinum neurotoxin was found in one of three samples at 12 weeks and in one of two samples at 24 weeks at 0% oxygen and 30 degrees C. When samples were inoculated with C. botulinum with amylase (0% oxygen), neurotoxin and sample spoilage was detected after only 1 week of storage. Challenge studies using proteolytic strains of C. botulinum mixed with Bacillus subtilis (amylase formers) also were performed with atmosphere conditions of oxygen at 0, 5, 10, and 15% (with 5% CO2 and 5% N2 as the balance). Under 10 and 15% oxygen conditions, neurotoxin was not detected after 1 week of storage, but sample spoilage was detected after the same period. Under 0% oxygen conditions, neurotoxin was detected at 1 week, but the sample remained organoleptically acceptable even after 2 weeks of storage. Both neurotoxin and sample spoilage were detected at 1 week of storage under 5% oxygen conditions. Based on these results, cocontamination of amylase-producing Bacillus with C. botulinum would increase the risk of foodborne botulism when aseptic rice samples are packed under low-oxygen conditions (<5%). Therefore, to ensure the safety of these products, packing under atmospheric containing more than 10% oxygen is recommended.

Botulinum Toxins↗
PubMed1999

Evaluation of the potential health effects of the atmospheric reaction products of polycyclic aromatic hydrocarbons.

The genotoxic risks from exposure to polycyclic aromatic hydrocarbons (PAHs) have long been recognized. Less well understood are the potential genotoxic risks of the atmospheric reaction products of this class of compounds. In this investigation, we have utilized several human cell assays to evaluate the genotoxicity of naphthalene, phenanthrene, and their atmospheric reaction products 1-nitronaphthalene, 2-nitronaphthalene (2NN), 1-hydroxy-2NN, 2-hydroxy-1-nitronaphthalene, 1,4-naphthoquinone, and 2-nitrodibenzopyranone (2NDBP). In addition, simulated atmospheric reaction products of naphthalene were generated in a 6,700 liter (L) Teflon environmental chamber, collected on a solid adsorbent, extracted, and fractionated by normal-phase high-performance liquid chromatography (HPLC). Individual fractions were then analyzed using gas chromatography/mass spectrometry (GC/MS), and tested for genotoxic effects. Genotoxicity was primarily determined using the human B-lymphoblastoid cell line, MCL-5, which expresses several transfected P450 and epoxide hydrolase genes. Mutagenicity was evaluated at both the heterozygous thymidine kinase (tk) locus and the hemizygous hypoxanthine phosphoribosyl transferase (hprt) locus, permitting detection of both intragenic and chromosomal scale mutational events. Test compounds were also screened using the CREST modified micronucleus assay. The results indicate that 2NN and 2NDBP possess greater mutagenic potency than their parent compounds, and, interestingly, both compounds induced significant increases in mutation frequency at the tk but not the hprt locus. These findings suggest a mechanistic difference in human cell response to 2NN and 2NDBP as compared to bacteria, where both compounds were previously shown to induce point mutations in the Salmonella typhimurium reversion assay. The genotoxicity of 2NN and 2NDBP in human cells, together with their high concentrations in ambient air relative to nitro-PAHs directly emitted from combustion sources, emphasizes the need to consider atmospheric reaction products of PAHs in assessments of the genotoxicity of air pollutants. We also investigated whether transfected cytochrome P450 monooxygenase activities were required to activate 2NN and 2NDBP to genotoxic species, and whether a single enzyme could be sufficient for metabolic activation. Three directly related cell lines with multiple (MCL-5), single (AHH-1 1A1), or no (L3) transfected cytochrome P450 genes were used. AHH-1 is additionally distinguished by elevated mutagenic response at the tk locus, a heterozygous mutation in p53, and apoptosis capacity. The effect of these metabolic and genetic differences on genotoxicity of 2NN, 2NDBP, and beta-naphthylamine (beta NA) was also investigated. The results indicated that 2NN and 2NDBP were not activated to genotoxic species through nitroreduction pathways. Mutagenicity induced at the tk locus was dependent on oxidative metabolism, provided by transfected cytochrome P450 enzymes in MCL-5 and AHH-1 1A1. Mutagenicity was not observed in the L3 cell line, which does not carry transfected cytochrome P450 activities. The negative response of beta NA in all cell lines indicates that, contrary to previous hypotheses, 2NN and beta NA are not activated by similar metabolic pathways in these human cell lines. Taken as a whole, these results suggest that the genotoxicity of nitro-PAHs in human cells requires oxidative metabolism.

Air Pollutants↗
PubMed2001

Impact of atmospheric deposition on the headworks of a wastewater treatment plant--a case study.

Specialized sampling equipment and ultra-clean analytical methodology were employed to quantify the concentrations or fluxes of mercury (Hg), cadmium (Cd) and polychlorinated biphenyl (PCBs) in ambient air, precipitation, runoff, sanitary sewer, and wastewater treatment plant (WWTP) influent. The relationship between the atmospheric deposition and runoff on controlled surfaces were explored for the three pollutants. The impact of the atmospheric deposition and runoff to the headwork loading of the WWTP were investigated. Atmospheric deposition was found to be the primary source of the mass of Cd, Hg, and PCBs in runoff from the controlled surfaces. Neither atmospheric deposition nor the runoff was the main sources of the three pollutants to the Detroit Wastewater Treatment Plant (WWTP). Wet weather flow contributes the main portion of the Cd, Hg, and PCBs loading to the WWTP.

Air Movements↗
PubMed2002

Does the direct effect of atmospheric CO2 concentration on leaf respiration vary with temperature? Responses in two species of Plantago that differ in relative growth rate.

The objective of this study was to investigate the direct effect of elevated atmospheric CO2 concentrations on leaf respiration in darkness (R) over a broad range of measurement temperatures. Our aim was to further elucidate the underlying mechanism(s) of the often-reported inhibition of leaf R by a doubling of the atmospheric CO2 concentration. Experiments were conducted using two species of Plantago that differed in maximum relative growth rate (fast-growing Plantago lanceolata L. and the slow-growing P. euryphylla Briggs, Carolin & Pulley). Rates of leaf respiration (R) were measured at atmospheric CO2 concentrations ranging from 75 to 2000 &mgr;mol mol-1 at temperatures from 12 to 42 degrees C. R was measured as CO2 release with a portable gas exchange system with infrared gas analysers. Our hypothesis was that the changes in temperature alter the flux coefficient (i.e. the extent to which changes in potential enzyme activity has an effect on the rate of a reaction) of enzymes potentially affected by CO2. Initial analysis of our results suggested that R was inhibited by elevated CO2 in both species, with the apparent degree of inhibition being greatest at low temperature. Moreover, the apparent degree of inhibition following a doubling of atmospheric CO2 concentration from 350 to 700 &mgr;mol mol-1 was similar to that reported by several previous studies (approximately 14% and 26% for P. lanceolata and P. euryphylla, respectively) at a temperature equal to the mean of the previous studies. However, subsequent correction for diffusion leaks of CO2 across the gas exchange's cuvette gaskets revealed that no significant inhibition had occurred in either species, at any temperature. The inhibitory effect of elevated CO2 on leaf respiratory CO2 release reported by previous studies may therefore have been overestimated.

Journal Article↗
PubMed2002

[Contribution to vegetable mercury from atmosphere and soil].

In this research, the characteristics of Hg accumulation in vegetable and the contribution of atmosphere and soil to vegetable Hg were studied by field observation and pot experiments. 11 kinds of vegetable were experimented in field. The results indicated that the Hg contents in roots and leaves of vegetables were higher than that in stems and fruits. In the natural condition, more than 60% of the assimilated Hg was distributed in the up-ground edible parts. The results of pot experiments showed that the Hg content of the edible parts of carrot and lettuce exceeded the Food Health Standard Value (FASV), when the atmospheric Hg content reached 57.6 +/- 14.7 ng.m-3. This result indicted that the contribution of atmosphere and soil to vegetable Hg were 70.4-90.7% and 9.3-29.6% respectively. So, the vegetable Hg was affected mainly by atmosphere Hg.

Air Pollutants↗
PubMed2002

[In vitro activity of clarithromycin and metronidazole against Helicobacter pylori in different incubation atmospheres].

The aim of this study was to determine the in vitro activity of clarithromycin and metronidazole using an agar dilution method to compare two different incubation atmospheres: a CO2 incubator and a jar with a microaerobic gas-generating system. Antibiotics were placed on plates in twofold dilutions ranging from 128 to 0.064 mg/l in Mueller-Hinton agar supplemented with 7% horse blood. The inoculum was prepared from 31 Helicobacter pylori isolates and was inoculated using a Steers replicator. Plates were incubated for 3 to 5 days and MICs were recorded as the lowest concentration of antibiotic inhibiting visible growth. Two different incubation atmospheres were used: a CO2 incubator set at 95% humidity and 10% CO2, and a jar with a gas-generating envelope that produces 7-10% O2 and 14% CO2 (BioMerieux). Clarithromycin resistance was found in 19% of strains both in the gas-generating system and the CO2 incubator. Metronidazole resistance was 23% in both atmospheres. MICs for clarithromycin in both atmospheres showed two dilutions of difference for 100% of the strains, and were slightly higher in the jar with a gas-generating envelope. However, MICs for metronidazole were higher when it was incubated in the CO2 incubator, and in 86.7% of strains the MICs showed < or = 2 dilutions of difference. No great discrepancies were found for either metronidazole or clarithromycin using the two methods.

Anti-Bacterial Agents↗