The aims of this study were to assess how different bacterial groups in bulk milk are related to bulk milk somatic cell count (SCC), bulk milk total bacterial count (TBC), and bulk milk standard plate count (SPC) and to measure the repeatability of bulk milk culturing. On 53 Dutch dairy goat farms, ...
Almond Harvesting, Processing, and Microbial Flora
This survey was set up on a statistical sampling plan to determine the microbial quality of almonds as they are received at the processing plant. The total aerobic bacterial count and yeast and mold count distribution were skewed by a few high counts compared with the majority of relatively low coun...
Estimation of total bacteria on mango surface by using ATP bioluminescence
This paper presents a rapid ATP assay for monitoring the total bacterial load associated with mango fruit surface. Conventional methods such as total plate count for the determination of total microbial counts are time consuming and prone to contamination resulting in low accuracy. Thus the need for quick and accurate methods for determination of total microbial count has led to development of many rapid techniques such as ATP bioluminescence. In this study the potential of ATP bioluminescence method for the determination of total bacterial count on mango surface has been evaluated using two types of luminescence techniques based on fluorescence spectroscopy and bioluminescence. Various mechanical and chemical extraction processes were employed for the extraction of ATP from bacterial cell...
The quality of minimally-processed carrots was studied during storage at 4 and 10 ?C by evaluating: (a) the physicochemical indices, namely: chlorogenic acid, carotenoids, sugars, and whiteness index (WI); (b) the microbial indices, namely: total bacterial count (TBC), coliforms, lactic acid bacteri...
A comparison of two types of scalders was conducted to determine their effectiveness in reducing bacterial contamination of poultry carcasses. A conventional hot-water scalder and a prototype model of a steam scalder were tested under commercial conditions. Total plate counts from steam-scalded birds were significantly lower than the counts of water-scalded birds immediately after scalding and again after picking. No differences in the two methods could be found after chilling. Coliform counts from steam-scalded birds were significantly lower than the counts from water-scalded birds immediately after scalding. No significant differences in coliform counts were detected when the two scald methods were compared after defeathering and chilling. PMID:4553146
The effect of bactericide treatment on planktonic bacterial communities in water cooling systems
Bactericides were applied to experimental open recirculating cooling-water systems at concentrations found to be effective under laboratory pure-culture conditions. Total aerobic plate counts and bacterial population structures were determined over a period of 48h. In all cases the total aerobic cou...
Bacterial analysis of water and sediment samples
Water and sediment samples collected from the Monongahela River, WV, were analyzed for total bacteria by direct counts using epifluorescence microscopy and the lipopolysaccharide (LPS) content by the limulus amebocyte lysate assay. The population ranges of bacteria in water and sediment samples were 2.4 to 6.5 x 10/sup 6//ml and 0.7 to 2 x 10/sup 10//g dry weight, respectively. The bound LPS in water samples ranges from 3 to 17 ng/ml. Sediment samples contained 17 to 34 ..mu..g of bound LPS/g dry weight of sediment. The relationship between bound LPS and bacterial cell number and the estimated bacterial carbon biomass by direct bacterial counts and LPS assay are discussed. The average ratios of the direct bacterial-count-derived carbon to the lipopolysaccharide-derived carbon for water and sediment samples were 1.03 +- 0.60 and 1.10 +- 0.53, respectively.
Sterilization of ground spices by electron beams irradiation
Each ground spice (Black Pepper, Turmeric, Ginger, Paprika and Basil), which was packaged into polyethylene film, was irradiated by electron beams at 5 different levels: 2, 4, 6, 8 and 10 kGy. Bacteriological tests for total bacterial count were carried out on spices before and after irradiation, but the tests for microfiora were carried out only before irradiation. Total bacterial count decreased in proportion to the level of electron beams. But the decreasing rate for Turmeric, Ginger and Basil was lower compared with that of other spices. The reason seems that rate of contamination by B. pumilus, which is thought as radiation resistant bacteria, was higher on these spices. (author)
Changes in bacterial communities of swine feces during continuous culture with starch
Denaturing gradient gel electrophorisis (DGGE) was used to monitor bacterial population changes during continuous culture of swine feces with starch as the carbohydrate source. Total anaerobe and aerobe counts were evaluated daily. Numbers of anaerobes were relatively constant, averaging 10(x9) CFU/...
Nonstained bacteria (NSB), rhodamine-stained bacteria (RSB), and fluorescence-labeled bacteria (FLB) were prepared from two enteric bacterial species, Escherichia coli and Enterococcus faecalis. Counts of CFU of NSB and RSB and total numbers of RSB and FLB were monitored over time, both in the prese...
Association between milking practices and psychrotrophic bacterial counts in bulk tank milk.
The objective of this work was to determine on-farm risk factors for psychrotrophic bacterial counts in bulk tank milk from dairy farms in Argentina. Raw milk samples from bulk tanks of 27 dairy farms were examined for total psychrotrophic counts (TPC), proteolytic psychrotrophic counts (PPC) and lipolytic psychrotrophic counts (LPC) (dependent or outcome variables). A survey recording infrastructure conditions, milking equipment and milking management (independent variables) was performed. Bivariate association proofs and logistic regression analyses were used to determine association between independent variables and psychrotrophic bacterial counts. Milk cooled in plate heat exchangers or barrel tanks were 16.39 and 10.52 times more likely to yield TPC and PPC above the standard established for high quality milk compared with milk cooled in bulk tanks, respectively. Periodic cleaning of cooling tanks (3 times a week or daily) was associated with lower TPC (approximately 1.5 log CFU/ml) than weekly cleaning frequency and farms where milkers did not wash their hands during milking time were 7.81 times more likely to have higher PPC. No association was found between LPC and any of the independent variables. The only variable associated with TPC and PPC in a logistic regression model was the refrigeration system used on the farm. Dairy farms that possessed bulk milk cooling tanks yielded the lowest bacterial counts. Results of this study highlight the importance of both the type of cooling system used on the farm and its adequate hygienic maintenance for obtaining low pshychrotrophic counts at dairy farm. PMID:23102468
The effects of bacterial injection, leg ablation and bacterial injection/leg ablation combination on cellular and biochemical parameters of the crab Carcinus aestuarii were evaluated. Total haemocyte count (THC), haemocyte volume, haemocyte proliferation, phenoloxidase (PO) activity in both haemocyte lysate (HL) and cell-free haemolymph (CFH) and CFH glucose levels were used as biomarkers of stress in crabs. After 24h following bacterial injection, no significant variation in THC were observed, whereas haemocyte diameter and volume decreased significantly in injected crabs with respect to controls. Haemocyte proliferation and glucose levels increased significantly in injected crabs, whereas no significant variations in PO activity was recorded between control and injected crabs. THC increa...
This study modeled the effect of ?-irradiation on reducing bacterial populations in space gochujang (Korean red pepper paste). The gochujang samples were ?-irradiated at 0, 5, 10, 15, and 20 kGy, and stored under accelerated storage condition (35?C for 10 days). During storage, total bacterial populations in gochujang samples were enumerated on plate count agar (PCA) on day 0, 1, 3, 5, 7, and 10. To calculate maximum specific growth rate (?max; log CFU/g/day), lag phase duration (day), low asymptote (Y 0; log CFU/g), upper asymptote (Y max; log CFU/g), and surviving cell counts recovered with PCA were fitted to the Baranyi equation. The parameters then were further expressed as a function of irradiation dose. Total bacterial populations in gochujang were decreased to below detection limit ...
The aim of this study was to establish the particular biohydrogen-production related microbial community structure in a starch-feeding dark fermentation agitated granular sludge bed (AGSB) reactor which was operated under pH 6.0 and 5.5 as well as under different hydraulic retention times (HRTs). The bacterial community diversity and percent of their cell count of the bioreactor were ascertained using denaturing gradient gel electrophoresis (DGGE) and fluorescence in situ hybridization (FISH) individually. Based on the comparison of bacterial structure and hydrogen production efficiency under different HRT, no conclusion could be made on whether the diversity of Clostridium community could directly affect the reactor performance in these two pH systems. However, bacterial cell counts showed that the viable number of dominated Clostridium sp. changed along with the hydrogen production rate (HPR). It was believed that it could directly affect the hydrogen production efficiency. The highest HPR and hydrogen yield (HY) occurred when the reactor was operated at HRT 0.5 h, while the ratio of Clostridium sp. cell count and Bifidobacterium sp. cell count over the total Eubacteria cell count were around 40% and 40-60%, respectively. Therefore, we suggested that bacterial species which could degrade starch, such as Bifidobacterium sp. in this study, broke down starch into small molecules first and then these less complex compounds were utilized by the Clostridium species for hydrogen production. (author)
A fluorochrome-staining method using 5-cyano-2,3-ditoryl tetrazolium chloride (CTC) was improved to enhance the sensitivity of detection of metabolically active bacteria in activated sludge. The highest efficiency of CTC staining was obtained with 6 mM CTC in MOPS buffer at pH 6.5. CTC staining efficiency was also increased by adding a substrate mixture (0.05% peptone, 0.05% yeast extract and 1 mM glucose), Meldola's Blue as an electron transfer mediator and KCN. The bacterial counts detected by the CTC staining method thus improved accounted for 41-76% of the total counts in activated sludge with the average value being 54%. This value was approximately two-fold higher than those obtained by the traditional CTC staining assay which has been performed in phosphate buffer or phosphate-buffered saline without any addition of external substrate or electron transfer mediator. There was a high positive correlation between CTC-stained direct counts and the plate counts of aerobic chemoorganotrophic bacteria or viable cell counts measured using a LIVE/DEAD BacLight Bacterial Viability kit. The viable population in the activated sludges as measured by BacLight staining and plate counting accounted for 73±7.6% and 8.7±4.7% of the total population, respectively. These data suggested that most of the "viable but nonculturable" bacteria (i.e., BacLight-positive but unculturable population) potentially existing in the sludge system were so metabolically active as to be detectable by the improved CTC staining method.
Critical appraisal of air pouch infection model in rats.
The aim of this study was to assess the efficacy and pharmacokinetic profiles of gentamicin, vancomycin, and levofloxacin in a rat air pouch model, in which Staphylococcus aureus (ATCC 25293) was used as the test organism. Antibiotic treatments (i.p.) were started 1 hour after bacterial inoculation and continued for 5 days. Bacterial counts and antibiotic concentrations were determined in pouch exudates that were obtained on the 5th day of antibiotic treatment. The following observations were made: 1) The concentrations of gentamicin or vancomycin in the exudate were found to be below the detection limit. 2) Levofloxacin and ciprofloxacin exhibited a dose-dependent effect on bacterial counts in the exudate. 3) The antibacterial efficacy of levofloxacin was found to be enhanced when the total daily dose of 10 mg was divided into smaller parts. The present study also showed that the air pouch infection model was a valuable tool to assess the pharmacokinetic and pharmacodynamic properties of antibiotics. PMID:22371910
Effects of voyage routing on the survival of microbes in ballast water
This study examines the use of patterns of variation in voyage routing water temperature to lighten the burden of on board ballast water management. Experimental results from all six ships in this study indicate that total bacterial counts decreased during the first six days of the voyage, regardless of trends in temperature variation. The ability of temperature to maintain bacterial counts at a certain level was obvious when temperature continuously decreased to less than 15^oC, or rose within the same range. The results of the bacterial analyses show that effective use of voyage routing yielding patterns of variations in water temperature may assist ballast water management in some cases. The testing regime in this study reveals the effects on causing increased mortality in the ballast w...
Bacteriological quality of raw milk used for production of a Brazilian farmstead raw milk cheese.
The objective of this study was to evaluate the bacteriological quality of raw cow's milk utilized for the production of Traditional Minas Serro cheese, a Brazilian farmstead raw milk cheese. Raw milk samples were collected from six farmstead cheese operations manufacturing raw milk cheese from cow's milk. Coliform count (CC) and Escherichia coli counts were determined using Petrifilm™ EC plates, and Staphylococcus aureus counts were determined using Petrifilm™ Staph Express count plates. The standard plate count (SPC) was determined using plate count agar. The somatic cell count (SCC) was determined with a DeLaval cell counter. The detection of Listeria monocytogenes was based in the ISO 11290-1 protocol. A total of 165 samples were analyzed, and the SPC was 1.85-7.88 log CFU/mL. Coliform were detected in 140 (84.8%) of the 165 samples, with counts of 1-6.39 log CFU/mL. E. coli was detected in 17 (10.3%) samples, with counts of 1-2.18 log CFU/mL. The SCC in raw milk was 10,000-1,390,000 cells per mL, with mean and geometric mean values of 247,000 and 162,181, respectively. The SCC did not differ significantly between the seasons (p>0.05), but differed between different farms (pcheese has a low incidence of L. monocytogenes and a high incidence of S. aureus, and suggest that measurements (such as SCC or SPC) may not serve as a predictor of other bacterial (including pathogenic) presence. PMID:22217108
The objective of this study was to determine on-farm risk factors for bacteriological quality of bulk tank milk. Bulk tank raw milk quality was evaluated on all Prince Edward Island dairy herds (n = 235) over a 2-yr period (March 2005 to March 2007). Biweekly total bacterial, preliminary incubation, laboratory pasteurization, and coliform counts were conducted using a Petrifilm culture system. For the assessment of risk factors, a case-control study was conducted from January 2006 to May 2007. Case and control herds were defined based on the last 6 analyses of bulk tank bacterial counts before on-farm evaluation. Cases were herds that had multiple elevated counts for any of the parameters measured. A total of 69 herds (39 cases and 30 control herds) were evaluated. Data collection included 1) observation and questionnaire on basic hygiene and farm management practices; 2) complete wash analysis of the milking equipment, monitoring the presence of bacterial films on equipment and evaluation of cooling system function; and 3) environmental and cow hygiene scoring. Data were analyzed using multivariable logistic regression. The results of the final model indicated that high alkalinity in the wash water and poor teat-end cleanliness were associated with high bacterial counts in bulk tank milk (odds ratios = 12 and 5.3, respectively). It was also observed that high water temperature of detergent wash and the use of a water softener were associated with low bacterial counts in bulk tank milk (odds ratios = 0.87 and 0.11, respectively). A significant association between udder hair clipping and teat-end cleanliness was also observed. In conclusion, this study highlights the importance of udder hygiene and milking system washing factors on hygienic quality of bulk tank milk. PMID:19447996
Aims: To identify the dominant culturable and nonculturable microbiota of rainbow trout intestine.Methods and Results: Microbial density of rainbow trout intestine was estimated by direct microscopic counts (4('),6-diamidino-2-phenylindole, DAPI) and by culturing on tryptone soya agar (TSA). Differential gradient gel electrophoresis analysis of bacterial DNA from intestinal samples, re-amplification of bands and sequence analysis was used to identify the bacteria that dominated samples where aerobic counts were less than or equal to2% of the DAPI counts. 16S rDNA gene sequences of 146 bacterial isolates and three sequences of uncultured bacteria were identified. A set of oligonucleotide probes was constructed and used to detect and enumerate the bacterial community structure of the gastrointestinal tract of rainbow trout by fluorescence in situ hybridization (FISH). Members of the gamma subclass of Proteobacteria (mainly Aeromonas and Enterobacteriaceae) dominated the bacterial population structure. Acinetobacter, Pseudomonas, Shewanella, Plesiomonas and Proteus were also identified together with isolates belonging to the beta subclass of Proteobacteria and Gram-positive bacteria with high and low DNA G + C content. In most samples, the aerobic count (on TSA) was 50-90% of the direct (DAPI) count. A bacterium representing a previously unknown phylogenetic lineage with only 89% 16S rRNA gene sequence similarity to Anaerofilum pentosovorans was detected in intestinal samples where aerobic counts were less than or equal to2% of direct (DAPI) counts. Ten to 75% of the microbial population in samples with low aerobic counts hybridized (FISH) with a probe constructed against this not-yet cultured bacterium.Conclusions: Proteobacteria belonging to the gamma subclass dominated the intestinal microbiota of rainbow trout. However, in some samples the microflora was dominated by uncultivated, presumed anaerobic, micro-organisms. The bacterial population structure of rainbow trout intestine, as well as total bacterial counts, varied from fish to fish.Significance and Impact of the Study: Good correlation was seen between cultivation results and in situ analysis, however, a molecular approach was crucial for the identification of organisms uncultivated on TSA
Occurrence and diversity of bacterial communities in Tuber magnatum during truffle maturation.
Tuber magnatum, an ascomycetous fungus and obligate ectomycorrhizal symbiont, forms hypogeous fruit bodies, commonly called Italian white truffles. The diversity of bacterial communities associated with T. magnatum truffles was investigated using culture-independent and -dependent 16S rRNA gene-based approaches. Eighteen truffles were classified in three groups, representing different degrees of ascocarp maturation, based on the percentage of asci containing mature spores. The culturable bacterial fraction was (4.17 +/- 1.61) x 10(7), (2.60 +/- 1.22) x 10(7) and (1.86 +/- 1.32) x 10(6) cfu g(-1) for immature, intermediate and mature ascocarps respectively. The total of bacteria count was two orders of magnitude higher than the cfu g(-1) count. Sequencing results from the clone library showed a significant presence of alpha-Proteobacteria (634 of the 771 total clones screened, c. 82%) affiliated with Sinorhizobium, Rhizobium and Bradyrhizobium spp. The bacterial culturable fraction was generally represented by gamma-Proteobacteria (210 of the 384 total strains isolated, c. 55%), which were mostly fluorescent pseudomonads. Fluorescent in situ hybridization confirmed that alpha-Proteobacteria (85.8%) were the predominant components of truffle bacterial communities with beta-Proteobacteria (1.5%), gamma-Proteobacteria (1.9%), Bacteroidetes (2.1%), Firmicutes (2.4%) and Actinobacteria (3%) only poorly represented. Molecular approaches made it possible to identify alpha-Proteobacteria as major constituents of a bacterial component associated with T. magnatum ascoma, independently from the degree of maturation. PMID:17686021
Fresh dried and old dried sangari (Prosopis cineraria) were treated with 0, 2.5, 5.0, and 7.0 kGy of irradiation and subsequently stored at ambient temperatures. Proximate values and total bacterial counts were evaluated immediately after irradiation and at regular intervals of 1 month during 3 months of storage. No significant changes were found in moisture, fat, protein, ash and fiber contents. Total sugar content was increased in both control and irradiated samples possibly due to conversion of starch into sugars. Irradiation treatment reduces total bacterial counts of dried samples of both fresh and old dried sangari. However, a dose of 5.0 kGy completely decontaminated both sangari and there was no microbial growth in 5.0 kGy irradiated samples during the storage period. Irradiation at 5.0 kGy was enough to extend the shelf-life of dried sangari up to 3 months without any significant change in the nutritional qualities. - Highlights: > Sangari (Prosopis cineraria) was irradiated and stored at ambient temperature. > No significant changes were observed in proximate analysis during storage. > Starch content was decreased during storage at all irradiation doses. > A dose of 5 kGy was found appropriate to eliminate total bacterial counts.
Effect of a Bioemulsificant Exopolysaccharide (EPS2003) on Abundance and Vitality of Marine Bacteria
The aim of this work has been to analyze the effects of a bioemulsificant exopolysaccharide (EPS2003) on the abundance and vitality of natural marine microbial population. Harbor seawater microcosms, supplemented with bioemulsificant EPS2003 (at different concentrations), were monitored over 20 days. The microbial community dynamic was analyzed by measurement of bacterial density (total and cultivable count) and vitality (live/dead count and total RNA amount). The results obtained show that addition of bioemulsificant (also at different concentrations), as sole carbon source, supported growth of the indigenous bacterial populations and revealed that this substance is optimal for use in the participations of recovery of environment polluted from oil. In comparison, an analysis with commerci...
Prevalence of antibiotic-resistant bacteria in herbal products.
The objective of this study was to determine the prevalence of antibiotic-resistant bacteria in various herbal products. Twenty-nine herbal supplements (18 traditional and 11 organic products) were purchased from stores and analyzed microbiologically. Total bacterial counts were determined by pour plate and surface spreading on tryptic soy agar (TSA). Antibiotic-resistant bacteria were enumerated on TSA supplemented with ceftriaxone (64 microg/ml) or tetracycline (16 microg/ml). Total bacterial counts ranged from goldenseal contained low levels of resistant bacteria. Fifty-two isolates were further evaluated against nine antibiotics, and the prevalence of antibiotic resistance was in the following order: ampicillin, nalidixic acid, trimethoprim, ceftriaxone, and streptomycin. Resistant bacteria were identified as Bacillus spp., Erwinia spp., and Ewingella americana. Staphylococcus spp., Enterobacter cloacae, and Stenotrophomonas maltophilia also were isolated. The presence of antibiotic-resistant bacteria and pathogens in these herbal products suggests that production and use of these products may need further evaluation. PMID:18680952
We present a single molecule method for counting proteins within a diffraction-limited area when using photoactivated localization microscopy. The intrinsic blinking of photoactivatable fluorescent proteins mEos2 and Dendra2 leads to an overcounting error, which constitutes a major obstacle for their use as molecular counting tags. Here, we introduce a kinetic model to describe blinking and show that Dendra2 photobleaches three times faster and blinks seven times less than mEos2, making Dendra2 a better photoactivated localization microscopy tag than mEos2 for molecular counting. The simultaneous activation of multiple molecules is another source of error, but it leads to molecular undercounting instead. We propose a photoactivation scheme that maximally separates the activation of different molecules, thus helping to overcome undercounting. We also present a method that quantifies the total counting error and minimizes it by balancing over- and undercounting. This unique method establishes that Dendra2 is better for counting purposes than mEos2, allowing us to count in vitro up to 200 molecules in a diffraction-limited spot with a bias smaller than 2% and an uncertainty less than 6% within 10 min. Finally, we demonstrate that this counting method can be applied to protein quantification in vivo by counting the bacterial flagellar motor protein FliM fused to Dendra2. PMID:23045631
Mechanisms of membrane fusion: disparate players and common principles
We present a single molecule method for counting proteins within a diffraction-limited area when using photoactivated localization microscopy. The intrinsic blinking of photoactivatable fluorescent proteins mEos2 and Dendra2 leads to an overcounting error, which constitutes a major obstacle for their use as molecular counting tags. Here, we introduce a kinetic model to describe blinking and show that Dendra2 photobleaches three times faster and blinks seven times less than mEos2, making Dendra2 a better photoactivated localization microscopy tag than mEos2 for molecular counting. The simultaneous activation of multiple molecules is another source of error, but it leads to molecular undercounting instead. We propose a photoactivation scheme that maximally separates the activation of different molecules, thus helping to overcome undercounting. We also present a method that quantifies the total counting error and minimizes it by balancing over- and undercounting. This unique method establishes that Dendra2 is better for counting purposes than mEos2, allowing us to count in vitro up to 200 molecules in a diffraction-limited spot with a bias smaller than 2% and an uncertainty less than 6% within 10 min. Finally, we demonstrate that this counting method can be applied to protein quantification in vivo by counting the bacterial flagellar motor protein FliM fused to Dendra2. PMID:18496517
Antibiotic resistance and R plasmids in coliforms isolated from some Malaysian cooked foods.
Forty samples of Malaysian cooked foods were examined for the presence of antibiotic-resistant coliforms and R plasmids. Twenty seven (68%) of the foods had antibiotic-resistant coliforms and 5 (13%) had R plasmids. Nineteen samples (48%) had total bacterial counts over 10(6) per gm and in 5 samples, no coliforms were detected. Our findings show that cooked food may be one possible way by which R plasmids are spread. The control of the spread of R plasmids is discussed. PMID:7147009
Abstract in portuguese Padronizou-se um método de reação em cadeia da polimerase (PCR) multiplex para detecção de Escherichia coli O157:H7 e avaliou-se a eficiência da PCR e de um método de cultivo convencional em placas na detecção desse patógeno experimentalmente adicionado em leite estéril e em leite cru com baixa contagem bacteriana total (média de 4,01 x 10³ UFC/ml) e com alta contagem bacteriana (média de 2,10 x 10(6) UFC/ml). Foram padronizadas duas reações de PCR com o u (more) so dos primers: "A" (RfbF; RfbR e FLICh7F/FLICh7R) e "B" (SLT-IF/SLTIR e SLT-IIF/SLT-IIR). A detecção de E. coli O157:H7 (1UFC/ml) a partir do leite estéril e do leite cru com baixa contaminação bacteriana foi possível quando se utilizou o método de contagem em placas e a PCR. A sensibilidade dos dois métodos foi menor quando se testou o leite cru com alta contaminação microbiana, sendo o método convencional mais sensível. Os resultados indicam que a presença de outros microrganismos, em alta quantidade no leite, dificulta a detecção de E. coli O157:H7 pelos métodos utilizados. Abstract in english This experiment was carried out in order to evaluate the effect of the raw milk bacterial count on the efficiency of a multiplex polymerase chain reaction and a conventional plate count method for detection of Escherichia coli O157:H7. This pathogen was experimentally inoculated into sterile milk, raw milk with low bacterial count (count mean of 4.01 x 10³ cfu/ml) and, raw milk with high bacterial count (mean 2.10 x 10(6) cfu/ml). Two protocols of PCR were standardized u (more) sing primers "A" (Rfbf and Rfbr and FLICh7F/FLICh7R) and "B" (SLT-IF/SLTIR and SLT-IIF/SLT-IIR). Both conventional plate count and PCR methods were able to detect the presence of E. coli O157:H7 in either sterile milk or raw milk with low bacterial count initially inoculated with 1cfu of E. coli O157:H7 per ml. The sensibility of both methods for high-contaminated raw milk samples was lower, being the conventional approach more sensitive. These results indicate that high bacterial count in raw milk can affect E. coli O157:H7 detection.
In Bangladesh, a number of screening tests for asymptomatic bacteriuria in pregnancy are in practice. The objective of this study was to assess the validity and cost-effectiveness of these screening tests. A total of 600 apparently healthy pregnant mothers were included in this study. The validity of the screening tests was calculated against the urine culture as 'gold standard'. Incremental cost-effective ratio between the screening test methods and the least costly method (microscopic urine analysis) was calculated. Bacterial count/oil-immersion field in Gram-stained smear of urine was the most sensitive (91.7%) and specific (97.2%). Incremental cost per additional positive cases of bacterial count, leukocyte esterase and combination of leukocyte esterase and nitrite were US$3, US$25 and US$23, respectively. Gram staining may be the alternative approach to traditional routine urinalysis for the screening of asymptomatic bacteriuria during pregnancy in clinical practice in Bangladesh, as well as other developing countries. PMID:22185534
Objectives The presence of bacterial biofilm, tolerance to antibiotics and dysfunctional activity of phagocytic cells are all related to difficulties in eradicating foreign-body infections. We aimed to quantify the presence of intracellular Staphylococcus aureus and to study the extent to which the intracellular activity of antibiotics might determine their efficacy against an experimental rat tissue-cage model of foreign-body infection. Methods Using this model, animals were treated for 7 days with 100 mg/kg/day levofloxacin or 200 mg/kg/12 h cloxacillin, or were left untreated. Antibiotic efficacy was evaluated by means of bacterial counts from tissue-cage fluid (TCF); these counts were derived separately in total, intracellular and extracellular bacteria. The presence of intracellular b...
Yields from blood cultures of patients with suspected paratyphoid fever A
Abstract in english The yield and speed of detection of Salmonella enterica serotype Paratyphi A from the blood of patients with suspected paratyphoid fever A in 13 500 paired aerobic and anaerobic bottles (AEB, ANB) that were each filled with 5 ml of blood by the BacT/ALERT 3D system were compared, and the blood bacterial counts of 1 000 probable patients were estimated by pour plate method. A total of 4 060 isolates were recovered, of these, 3 149 were recovered from both AEB and ANB, 461 (more) from the AEB only, and 450 from the ANB only. The estimating median bacterial count in blood from 400 patients was 0.5 CFU/ml. The research findings demonstrate that the blood volume drawn is an important factor determining the yields from blood cultures. Growth of significantly more isolates was detected earlier in AEB.
Bacteria and virus particles were harvested from water samples by ultracentrifugation directly onto Formvar-coated electron microscopy grids and counted in a transmission electron microscope. With this technique, we have counted and sized bacteria and viruses in marine water samples and during laboratory incubations. By X-ray microanalysis, we could determine the elemental composition and dry-matter content of individual bacteria. The dry weight/volume ratio for the bacteria was 600 fg of dry weight microns-3. The potassium content of the bacteria was normal compared with previous estimates from other bacterial assemblages; thus, this harvesting procedure did not disrupt the bacterial cells. Virus particles were, by an order of magnitude, more abundant than bacteria in marine coastal waters. During the first 5 to 7 days of incubation, the total number of viruses increased exponentially at a rate of 0.4 day-1 and thereafter declined. The high proliferation rate suggests that viral parasitism may affect mortality of bacteria in aquatic environments.
Occurrence and diversity of bacterial communities in Tuber magnatum during truffle maturation
Summary Tuber magnatum, an ascomycetous fungus and obligate ectomycorrhizal symbiont, forms hypogeous fruit bodies, commonly called Italian white truffles. The diversity of bacterial communities associated with T. magnatum truffles was investigated using culture-independent and -dependent 16S rRNA gene-based approaches. Eighteen truffles were classified in three groups, representing different degrees of ascocarp maturation, based on the percentage of asci containing mature spores. The culturable bacterial fraction was (4.17 +- 1.61) x 107, (2.60 +- 1.22) x 107 and (1.86 +- 1.32) x 106 cfu g-1 for immature, intermediate and mature ascocarps respectively. The total of bacteria count was two orders of magnitude higher than the cfu g-1 count. Sequencing results from the clone library showed a ...
Contribution of bacterial cells to lacustrine organic matter based on amino sugars and D-amino acids
Amino sugars (ASs), D-amino acids (D-AAs), and bacterial cell counts were measured in two Swiss lakes to study the contribution of bacterial cells to organic matter (OM) and the fate of ASs and bacterial amino biomarkers during OM degradation. Concentrations of individual ASs (glucosamine, galactosamine, muramic acid, and mannosamine) in the particulate and total OM pools were analyzed in water-column profiles of Lake Brienz (oligotrophic and oxic throughout the entire water column) and Lake Zug (eutrophic, stratified, and permanently anoxic below 170 m) in spring and in fall. Generally, carbon-normalized AS concentrations decreased with water depth, indicating the preferential decomposition of ASs. For Lake Brienz the relative loss of particulate ASs was higher than in Lake Zug, suggesting enhanced AS turnover in an oligotrophic environment. AS ratio changes in the water column revealed a replacement of plankton biomass with OM from heterotrophic microorganisms with increasing water depth. Similar to the ASs, highest carbon normalized D-AA concentrations were found in the upper water column with decreasing concentrations with depth and an increase close to the sediments. In Lake Zug, an increase in the percentage of D-AAs also showed the involvement of bacteria in OM degradation. Estimations of OM derived from bacterial cells using cell counts and the bacterial biomarkers muramic acid and D-AAs gave similar results. For Lake Brienz 0.2-14% of the organic carbon pool originated from bacterial cells, compared to only 0.1-5% in Lake Zug. Based on our estimates, muramic acid appeared primarily associated with bacterial biomass and not with refractory bacterial necromass. Our study underscores that bacteria are not only important drivers of OM degradation in lacustrine systems, they also represent a significant source of OM themselves, especially in oligotrophic lakes.
A cross sectional study was conducted to enumerate total viable bacteria (TBC), coliforms, Escherichia coli and Staphylococcus aureus in raw (n=120) and processed (n=20) milk from individual farms from three smallholder dairy schemes of Zimbabwe between October, 2009 and February, 2010. Data on management factors were collected using a structured questionnaire. A standard pour plate technique was used to enumerate total viable bacteria, while for coliforms, E. coli and S. aureus, counts were assessed by the spread plate technique. The association of total viable bacterial counts and management factors was assessed using univariable and a linear regression model. The log10 TBC for raw milk differed significantly (P<0.05) amongst the schemes with the lowest (5.6+/-4.7log10 cfu/ml) and highes...
Abstract The present study aims to increase the shelf life of Nile tilapia (Oreochromis niloticus) fish using frozen green tea extract (GTE) with different concentrations (2, 4 and 6%, w/v). Biochemical characteristics (pH, total volatile basic nitrogen, trimethylamine-nitrogen and thiobarbituric acid), microbiological parameters (total viable bacterial count, psychrophilic bacteria and total mold and/or yeast count) and sensory quality outlines were determined during storage period at 4C. The results indicated that the samples stored on frozen GTE had better biochemical and microbiological characteristics, which resulted in increasing the shelf life of fish samples. The samples stored on frozen GTE with different concentrations (2, 4 and 6%, w/v) were rejected after 10, 14 and 14 days of ...
Detailed evaluation of a newly attained fungal pigment from Monascus purpureus in meat burgers.
Beef burgers with red pigment extracted from Monascus purpureus, used as a natural colouring agent, were examined for chemical compositions, physical properties, microbiological aspects and organoleptic evaluation. Beef burgers with Monascus pigment showed higher nutritional values compared with control samples. Nutritional values were proportionally enhanced by increasing pigment concentration. Synthetic dye samples had the lowest values of nutrients. Cooking loss percentage and water holding capacity were lower in all treatments compared with control samples, and vice versa for plasticity. The initial total bacterial count, Staphylococcus aureus count and coliform count were determined. Extending storage period up to 90 days severely reduced all tested microorganisms. By increasing the M. pigment concentration, the colour was significantly increased. Insignificant differences in colours were noticed among various treatments. Flavour and body and texture scores were insignificantly different. Microbial inhibition percentage of beef burger samples was increased by increasing the Monascus pigment concentration up to 0.8 g/kg. PMID:22394332
Abstract in english Ozonation tests with and without prior filtration by means of a 50 micron mesh cartridge filter were conducted with primary sanitary effluents. Filtration led to increased inactivation efficiencies with regard to total and thermotolerant coliforms but it did not seem to influence heterotrophic plate count (HPC) bacteria inactivation efficiencies significantly. Application of the Chick-Watson model to experimental data obtained in the situation of constant inactivation sho (more) wed that the ozone dosage was more important to bacterial inactivation than the contact time with regard to the cases of thermotolerant coliform inactivation in filtered samples and HPC bacteria and total coliform inactivation in non-filtered samples.
Data on the microbial quality of food service kitchen surfaces and ready-to-eat foods were collected over a period of 10 years in Rutgers University dining halls. Surface bacterial counts, total aerobic plate counts, and total and fecal coliform counts were determined using standard methods. Analysis was performed on foods tested more than 50 times (primarily lunch meats and deli salads) and on surfaces tested more than 500 times (36 different surfaces types, including pastry brushes, cutting boards, and countertops). Histograms and statistical distributions were determined using Microsoft Excel and Palisades Bestfit, respectively. All data could be described by lognormal distributions, once data above and below the lower and upper limits of detection were considered separately. Histograms for surfaces counts contained one peak near 1 CFU/4 cm2. Surfaces with higher levels of contamination tended to be nonmetal, with the exception of buffalo chopper bowls, which commonly had high counts. Mean counts for foods ranged from 2 to 4 log CFU/g, with shrimp salad, roast beef, and bologna having higher means. Coleslaw, macaroni salad, and potato salad (all commercially processed products, not prepared in the dining halls) had lowest overall means. Coliforms were most commonly found in sealeg salad (present in 61% of samples) and least commonly found in coleslaw (present in only 7% of samples). Coliform counts (when present) were highest on average in shrimp salad and lowest in coleslaw. Average coliform counts for most products were typically between 1 and 2 log most probable number per gram. Fecal coliforms were not typically found in any deli salads or lunch meats. PMID:14717367
Fillets of a hake, Merluccius merluccius hubbsi, were exposed to 2 kGy, 6 kGy, and 10 kGy of ionizing radIation from a Cobalt 60 source and were subsequently stored frozen at 0 degree C. Both these irradiated samples and control samples were examined to determine their bacterial counts and organoleptic qualities (texture, elasticity odor, color, and drip loss) for a period of seven weeks following the irradiation. The irradiated fillets showed an initial marked decrease in the total number of bacteria--amounting to roughly one order of magnitude for those exposed to 2 kGy and roughly three orders of magnitude for those exposed to 6 kGy and 10 kGy as compared to the controls. The samples irradiated with 6 and 10 kGy had bacterial counts well below the minimum acceptable level of 0.8 x 10(6) bacteria per gram for the entire seven-week study period. Regarding organoleptic quality, the fillets exposed to 2 kGy and 6 kGy were found to retain acceptable qualities for an average of about six weeks, somewhat longer than the controls and other irradiated samples. Considering both bacterial counts and organoleptic qualities, the most effective of the three radiation doses employed was 6 kGy.
The relative role of eukaryotic versus prokaryotic microorganisms in phenanthrene transformation was measured in slurries of coastal sediment by two different approaches: detection of marker metabolites and use of selective inhibitors on phenanthrene biotransformation. Phenanthrene biotransformation was measured by polar metabolite formation and CO[sub 2] evolution from [9-[sup 14]C]phenanthrene. Both yeasts and bacteria transformed phenanthrene in slurries of coastal sediment. Two products of phenanthrene oxidation by fungi, phenanthrene trans-3,4-dihydrodiol and 3-phenanthrol, were produced in yeast-inoculated sterile sediment. However, only products of phenanthrene oxidation typical of bacterial transformation, 1-hydroxy-2-naphthoic acid and phenanthrene cis-3,4-dihydrodiol, were isolated from slurries of coastal sediment with natural microbial populations. Phenanthrene trans-dihydrodiols or other products of fungal oxidation of phenanthrene were not detected in the slurry containing a natural microbial population. A predominant role for bacterial transformation of phenanthrene was also suggested from selective inhibitor experiments. Addition of streptomycin to slurries, at a concentration which suppressed bacterial viable counts and rates of [methyl-[sup 3]H]thymidine uptake, completely inhibited phenanthrene transformation. Treatment with colchicine, at a concentration which suppressed yeast viable counts, depressed phenanthrene transformation by 40%, and this was likely due to nontarget inhibition of bacterial activity. The relative contribution of eukaryotic microorganisms to phenanthrene transformation in inoculated sterile sediment was estimated to be less than 3% of the total activity. We conclude that the predominant degraders of phenanthrene in muddy coastal sediments are bacteria and not eukaryotic microorganisms. 35 refs., 2 figs., 1 tab.
There is an epidemiological association between influenza virus infection and meningococcal disease. Proposed mechanisms are the destruction of the normal epithelial barrier function of the upper respiratory tract by influenza virus or the expression of human or viral surface-exposed proteins that enhance bacterial adherence and/or invasion. To test these hypotheses, human nasopharyngeal mucosa specimens from a total of 19 individual donors were successfully infected with influenza B virus and then inoculated with serogroup B Neisseria meningitidis. Subsequent bacterial association with the epithelial surface was measured in three separate series of experiments by using transmission electron microscopy (n = 6), scanning electron microscopy (n = 6), and counting of viable bacteria within homogenates of explants (n = 7). Penetration of the mucosa was estimated by measuring the count of viable bacteria recovered from explants after exposure to sodium taurocholate. Bacterial association with the surface of explants was time dependent over 24 h of superinfection. Influenza virus did not positively or negatively influence bacterial attachment to or penetration of explant mucosa compared to those of uninfected controls, even when the period of preincubation with virus was extended to 7 days. When proteins were purified from mucosal epithelium and immobilized on nitrocellulose membranes, N. meningitidis attached predominantly to bands corresponding to proteins of 210 and 130 kDa. In the presence of influenza virus infection, these proteins were gradually lost over the course of 72 h. In conclusion, influenza B virus did not increase association of serogroup B N. meningitidis with human nasopharyngeal mucosa. PMID:10338524
Few studies regarding wound treatment with topical antimicrobials evaluate change in the bacterial bioburden of the wound with treatment. This study sought out to determine the in vivo effect of cadexomer iodine antibacterial dressing on diabetic foot ulcers (DFUs) that were infected or achieved a critical level of colonisation, looking specifically at wound progression in relation to bioburden. Fifteen patients corresponding to 16 total DFUs met criteria of displaying clinical signs of infection or critical colonisation and were suitable for a topical antibacterial dressing. They underwent weekly treatment for 6 weeks. Cultures were taken at week 0, 3 and 6 as appropriate. At week 6 median log(10) bacterial count reduction of 1.0 was observed from baseline (p = 0·025). At week 3- a median log(10) bacterial count reduction of 0.3 was observed from baseline (p = 0·049). Over the study period there was a 53.6% median reduction of the wound surface area. There were no patients that completely healed their ulcer over the 6 week study period. There was a statistically significant median reduction in the bacterial load over the 6 week period (p = 0·025) as well as 3 weeks (p = 0·049). This was accompanied by a median reduction of 53.6% in ulcer surface area and 50% in ulcer depth from baseline to final. PMID:23136838
UV inactivation of pathogenic and indicator microorganisms
Survival was measured as a function of the dose of germicidal UV light for the bacteria Escherichia coli, Salmonella typhi, Shigella sonnei, Streptococcus faecalis, Staphylococcus aureus, and Bacillus subtilis spores, the enteric viruses poliovirus type 1 and simian rotavirus SA11, the cysts of the protozoan Acanthamoeba castellanii, as well as for total coliforms and standard plate count microorganisms from secondary effluent. The doses of UV light necessary for a 99.9% inactivation of the cultured vegetative bacteria, total coliforms, and standard plate count microorganisms were comparable. However, the viruses, the bacterial spores, and the amoebic cysts required about 3 to 4 times, 9 times, and 15 times, respectively, the dose required for E. coli. These ratios covered a narrower relative dose range than that previously reported for chlorine disinfection of E. coli, viruses, spores, and cysts.
Effects of calf diet, antioxidants, packaging type and storage time on beef steak storage.
The effect of basal dietary supplemented with vegetable oils plus vitamin E (sunflower, soybean, linseed and a basal diet control), type of packaging (MAP or vacuum), addition of natural antioxidant (grape seed, rosemary) and storage time (0, 7, 14 and 21 days) on lipid oxidation, color stability, vitamin E content, and total aerobic bacterial counts in steaks of Longissimus thoracis was studied. The triple interaction diet × time × packaging affected oxidative stability, redness and yellowness of the meat. TBARS values did not increase with time in vacuum-packaged samples for all dietary treatments. However, samples from MAP and control showed the highest TBARS values after 21 days of storage (0.72 mg MDA/kg of meat, Pantioxidant extracts and MAP maintained low total aerobic counts in steaks until the 21st day. Calves should be fed a diet supplemented with L-VE, stored in MAP and treated with grape seed extract to extend the shelf life of their meat. PMID:22193039
[Microbiological quality of wheat flour consumed in Morocco].
Cereal products (soft and hard wheat) are a basic staple food in the Moroccan diet. A total of 60 samples of two types of wheat flours used for human consumption were collected; 30 samples among this collection were obtained from various households using Moroccan varieties of wheat produced in traditional flour mills. The rest of the samples were purchased from retail wheat flour sources in the Rabat and Sale city markets. Standard plate counts (SPC), total and faecal coliforms, Clostridium, Salmonella spp., Shigella spp., Staphylococcus aureus, Listeria monocytogenes, yeast, lactic acid bacteria, and molds, were carried out to assess the microbiological quality of wheat flour. Microbiological interpretation of the criteria was performed according to standards implemented by the Codex Alimentarius Commission. Most frequent counts, in traditional and industrial wheat flour, were total aerobic mesophilic bacteria with an average 4 × 104 and 2.5 × 104 cfu/g, respectively. The results showed higher coliform and fungi counts in house than in commercial samples. Pathogenic flora as Salmonella spp., Shigella spp., S. aureus, L. monocytogenes, and Clostridium were not detected in all investigated samples. Bacterial strains isolated from both flours belong to the following genera: Enterobacter spp., Serratia spp., Klebsiella spp., Pantoea spp., Leclercia spp., Proteus spp. The most frequent genus of the investigated isolates was Aspergillus (81 %). Microbial counts were lower than the limit laid down in the Codex Alimentarius, attributing to these flours a satisfactory microbiological quality. PMID:22260306
Bacterial colonization and beta defensins in the female genital tract in HIV infection.
Beta defensins are antimicrobial peptides that serve to protect the host from microbial invasion at skin and mucosal surfaces. Here we explore the relationships among beta defensin levels, total bacterial colonization, and colonization by bacterial vaginosis (BV)-related bacteria and lactobacilli in the female genital tract in HIV infected women and healthy controls. Cervicovaginal lavage (CVL) samples were obtained from 30 HIV-infected women and 36 uninfected controls. Quantitative PCR assays were used to measure DNA levels of bacterial 16S ribosomal DNA (reflective of total bacterial load), and levels of three BV-related bacteria, three Lactobacillus species (L. crispatus, L. iners and L. jensenii), and total Lactobacillus levels in CVL. Levels of human beta defensins (hBD-2 and hBD-3) were quantified by ELISA. In viremic HIV+ donors, we found that CVL levels of bacterial 16S rDNA were significantly increased, and inversely correlated with peripheral CD4+ T cell counts in HIV+ women, and inversely correlated with age in both HIV+ women and controls. Although CVL DNA levels of BV-associated bacteria tended to be increased, and CVL levels of Lactobacillus DNAs tended to be decreased in HIV+ donors, none of these differences was significant. CVL levels of hBD-2 and hBD-3 were correlated and were not different in HIV+ women and controls. However, significant positive correlations between hBD-3 levels and total bacterial DNA levels in controls were not demonstrable in HIV+ women; the significant positive correlations of hBD2 or hBD-3 and three Lactobacillus species in controls were also not demonstrable in HIV+ women. These results suggest that HIV infection is associated with impaired regulation of innate defenses at mucosal sites. PMID:22716110
Bacterial population dynamics were examined during bioremediation of an African soil contaminated with Arabian light crude oil and nutrient enrichment (biostimulation). Polymerase chain reaction followed by denaturing gradient gel electrophoresis (DGGE) were used to generate bacterial community fingerprints of the different treatments employing the 16S ribosomal ribonucleic acid (rRNA) gene as molecular marker. The DGGE patterns of the nutrient-amended soils indicated the presence of distinguishable bands corresponding to the oil-contaminated-nutrient-enriched soils, which were not present in the oil-contaminated and pristine control soils. Further characterization of the dominant DGGE bands after excision, reamplification and sequencing revealed that Corynebacterium spp., Dietzia spp., Rhodococcus erythropolis sp., Nocardioides sp., Low G+C (guanine plus cytosine) Gram positive bacterial clones and several uncultured bacterial clones were the dominant bacterial groups after biostimulation. Prominent Corynebacterium sp. IC10 sequence was detected across all nutrient-amended soils but not in oil-contaminated control soil. Total heterotrophic and hydrocarbon utilizing bacterial counts increased significantly in the nutrient-amended soils 2 weeks post contamination whereas oil-contaminated and pristine control soils remained fairly stable throughout the experimental period. Gas chromatographic analysis of residual hydrocarbons in biostimulated soils showed marked attenuation of contaminants starting from the second to the sixth week after contamination whereas no significant reduction in hydrocarbon peaks were seen in the oil-contaminated control soil throughout the 6-week experimental period. Results obtained indicated that nutrient amendment of oil-contaminated soil selected and enriched the bacterial communities mainly of the Actinobacteria phylogenetic group capable of surviving in toxic contamination with concomitant biodegradation of the hydrocarbons. The present study therefore demonstrated that the soil investigated harbours hydrocarbon-degrading bacterial populations which can be biostimulated to achieve effective bioremediation of oil-contaminated soil. PMID:21824988
Response of soil microbial biomass to 1,2-dichlorobenzene addition in the presence of plant residues
The impact of 1,2-dichlorobenzene on soil microbial biomass in the presence and absence of fresh plant residues (roots) was investigated by assaying total vital bacterial counts, vital fungal hyphal length, total culturable bacterial counts, and culturable fluorescent pseudomonads. Diversity of the fluorescent pseudomonads was investigated using fatty acid methyl ester (FAME) characterization in conjunction with metabolic profiling of the sampled culturable community (Biolog). Mineralization of [{sup 14}C]1,2-dichlorobenzene was also assayed. Addition of fresh roots stimulated 1,2-dichlorobenzene mineralization by over 100%, with nearly 20% of the label mineralized in root-amended treatments by the termination of the experiment. Presence of roots also buffered any impacts of 1,2-dichlorobenzene on microbial numbers. In the absence of roots, 1,2-dichlorobenzene greatly stimulated total culturable bacteria and culturable pseudomonads in a concentration-dependent manner. 1,2-Dichlorobenzene, up to concentrations of 50 {micro}g/g soil dry weight had little or no deleterious effects on microbial counts. The phenotypic diversity of the fluorescent pseudomonad population was unaffected by the treatments, even though fluorescent pseudomonad numbers were greatly stimulated by both roots and 1,2-dichlorobenzene. The presence of roots had no detectable impact on the bacterial community composition. No phenotypic shifts in the natural population were required to benefit from the presence of roots and 1,2-dichlorobenzene. The metabolic capacity argued that the increased microbial biomass and shifts in metabolic capacity of the microbial biomass are responsible for enhanced degradation of 1,2-dichlorobenzene in the presence of decaying plant roots.
Bacterial counts under liquid cultivation using 96-well microplates were performed. The counts under liquid and under solid cultivation were equivalent in foods, although the counts under liquid cultivation exceeded those under solid cultivation in seawater, suggesting that some bacteria in seawater were viable but did not form detectable colonies. Phylogenetic analysis of bacteria obtained under liquid cultivation was also performed.
Microorganisms are an integral part of the biogeochemical processes in wetlands, yet microbial communities in sediments within constructed wetlands receiving acid mine drainage (AMD) are only poorly understood. The purpose of this study was to characterize the microbial diversity and abundance in a wetland receiving AMD using fluorescence in situ hybridization (FISH) analysis. Seasonal samples of oxic surface sediments, comprised of Fe(III) precipitates, were collected from two treatment cells of the constructed wetland system. The pH of the bulk samples ranged between pH 2.1 and 3.9. Viable counts of acidophilic Fe and S oxidizers and heterotrophs were determined with a most probable number (MPN) method. The MPN counts were only a fraction of the corresponding FISH counts. The sediment samples contained microorganisms in the Bacteria (including the subgroups of acidophilic Fe- and S-oxidizing bacteria and Acidiphilium spp.) and Eukarya domains. Archaea were present in the sediment surface samples at < 0.01% of the total microbial community. The most numerous bacterial species in this wetland system was Acidithiobacillus ferrooxidans, comprising up to 37% of the bacterial population. Acidithiobacillus thiooxidans was also abundant.
Microorganisms are an integral part of the biogeochemical processes in wetlands, yet microbial communities in sediments within constructed wetlands receiving acid mine drainage (AMD) are only poorly understood. The purpose of this study was to characterize the microbial diversity and abundance in a wetland receiving AMD using fluorescence in situ hybridization (FISH) analysis. Seasonal samples of oxic surface sediments, comprised of Fe(III) precipitates, were collected from two treatment cells of the constructed wetland system. The pH of the bulk samples ranged between pH 2.1 and 3.9. Viable counts of acidophilic Fe and S oxidizers and heterotrophs were determined with a most probable number (MPN) method. The MPN counts were only a fraction of the corresponding FISH counts. The sediment samples contained microorganisms in the Bacteria (including the subgroups of acidophilic Fe- and S-oxidizing bacteria and Acidiphilium spp.) and Eukarya domains. Archaea were present in the sediment surface samples at < 0.01% of the total microbial community. The most numerous bacterial species in this wetland system was Acidithiobacillus ferrooxidans, comprising up to 37% of the bacterial population. Acidithiobacillus thiooxidans was also abundant.
Abstract in english Background: The etiology of acute exacerbations of chronic obstructive pulmonary disease (COPD) is heterogeneous and still under discussion. Inflammation increases during exacerbation of COPD. The identification of inflammatory changes will increase our knowledge and potentially guide therapy. Aim: To identify which inflammatory parameters increase during COPD exacerbations compared to stable disease, and to compare bacterial and viral exacerbations. Material and Methods: (more) In 85 COPD patients (45 males, mean age 68 ± 8 years, FEV1 46 ± 17% of predicted) sputum, nasopharyngeal swabs and blood samples were collected to identify the causative organism, during a mild to moderate exacerbation. Serum ultrasensitive C reactive protein (CRP), fibrinogen and interleukin 6 (IL 6), neutrophil and leukocyte counts were measured in stable conditions, during a COPD exacerbation, 15 and 30 days post exacerbation. Results: A total of 120 mild to moderate COPD exacerbations were included. In 74 (61.7%), a microbial etiology could be identified, most commonly Mycoplasma pneumoniae (15.8%), Rhinovirus (15%), Haemophilus influenzae (14.2%), Chlamydia pneumoniae (11.7%), Streptococcus pneumoniae (5.8%) and Gram negative bacilli (5.8%). Serum CRP, fibrinogen and IL 6, and neutrophil and leukocyte counts significantly increased during exacerbation and recovered at 30 days post exacerbation. Compared to viral exacerbations, bacterial aggravations were associated with a systemic inflammation of higher magnitude. Conclusions: Biomarkers of systemic inflammation increase during mild to moderate COPD exacerbations. The increase in systemic inflammation seems to be limited to exacerbations caused by bacterial infections.
The interaction between the gut microbiota and their mammalian host is known to have far-reaching consequences with respect to metabolism and health. We investigated the effects of eight days of oral antibiotic exposure (penicillin and streptomycin sulfate) on gut microbial composition and host metabolic phenotype in male Han-Wistar rats (n = 6) compared to matched controls. Early recolonization was assessed in a third group exposed to antibiotics for four days followed by four days recovery (n = 6). Fluorescence in situ hybridization analysis of the intestinal contents collected at eight days showed a significant reduction in all bacterial groups measured (control, 10(10.7) cells/g feces; antibiotic-treated, 10(8.4)). Bacterial suppression reduced the excretion of mammalian-microbial urinary cometabolites including hippurate, phenylpropionic acid, phenylacetylglycine and indoxyl-sulfate whereas taurine, glycine, citrate, 2-oxoglutarate, and fumarate excretion was elevated. While total bacterial counts remained notably lower in the recolonized animals (10(9.1) cells/g faeces) compared to the controls, two cage-dependent subgroups emerged with Lactobacillus/Enterococcus probe counts dominant in one subgroup. This dichotomous profile manifested in the metabolic phenotypes with subgroup differences in tricarboxylic acid cycle metabolites and indoxyl-sulfate excretion. Fecal short chain fatty acids were diminished in all treated animals. Antibiotic treatment induced a profound effect on the microbiome structure, which was reflected in the metabotype. Moreover, the recolonization process was sensitive to the microenvironment, which may impact on understanding downstream consequences of antibiotic consumption in human populations. PMID:21591676
The methods of sanitary inspection performed primarily by traditional culture methods are time consuming, laborious, and require complicated laboratory techniques. A number of instrumental methods have been introduced for the rapid determination of viable cells based on the metabolic activities of microorganisms. The DOX system is one of the newly developed rapid inspection methods. It has three independent incubators that hold 60 vials each can estimate viable bacterial cell number by measuring the respiration speed of microorganisms and also has a high correlation between the detection time (Dt) and the viable bacterial cell number. We made a quantification analysis of coliform, and identified the presence of Escherichia coli from various kinds of vegetable samples. A total of 131 vegetable samples were tested to compare the plate count of coliform to the count using the DOX method. The correlation coefficient for the estimation of coliform-bacterial cell number was 0.85, which theoretically suggested that the DOX system was able to detect one cell of coliform-bacteria after 17.7 h of incubation. Among the 131 samples, 20 samples were confirmed for the presence of E. coli-positive cells using the UV-lamp method. This study suggested that the DOX system performs better than the conventional method for the routine inspection of coliform and E. coli from vegetable samples. Therefore, this system could be useful for the rapid detection of coliform and E. coli from vegetable samples with minimum labor and cost.
The Use of Goosegrass (Eleusine indica) to Remediate Soil Contaminated with Petroleum
A greenhouse experiment was performed to evaluate effectiveness of goosegrass (Eleusine indica) in phytoremediation of soil contaminated with 8,247?mg?kg?1 of total petroleum hydrocarbons (TPH). We determined seed germination toxicity, soil microbial viable counts, catalase activity, dehydrogenase activity (DHA), and the concentrations of TPH and 14 polycyclic aromatic hydrocarbons (PAHs) in soil and plant tissue. After 5?months, the initial level of contamination was reduced by 47% in planted soil, whereas it was only reduced by 11% in nonplanted soil. Bacterial numbers were 72 times greater in the rhizosphere treated soil than in the unvegetated treatment at the end of the study. There was no correlation between microbial counts or DHA and catalase activity, and the correlation between m...
Boerewors is a South African fresh sausage preserved with 450mg/kg sulphur dioxide (SO"2). The preservative effects of rosemary (Ros; 260mg/kg) and chitosan (Chi; 10g/kg) were compared to SO"2. Eight boerewors models were formulated. Microbial, colour, lipid and sensory characteristics were evaluated. Chi and Chi in combination with other preservatives had a significant effect on reducing total bacterial, coliform and Enterobacteriaceae counts, comparable to SO"2. Chi, however, had a better effect on decreasing yeasts and mould counts than SO"2. Chi showed good colour properties comparable to SO"2. Ros showed comparable lipid stability to SO"2 but better when compared to Chi. Ros had a better effect on the sensory taste when compared to Chi, but SO"2 was still preferred. Reduced levels of ...
Monitoring of microbial changes in salted cabbage (Jeolimbaechu) during recycled brining operation
To investigate possible recycling of a brine solution for the production of salted cabbage (jeolimbaechu), bacterial cell counts in the brine solution and salted cabbages were measured after repeated salting processes. After a salting process with a 13% brine solution for 15 hr at 10?C, the salt concentration in brine and salted cabbage decreased to 9.0?9.9 and 1.5?3.2% (depending on parts), respectively. After 5 repetitions, the total microbial count in the brine solution and salted cabbage gradually increased to 8.9 and 8.7 log CFU/g, respectively. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCRDGGE) showed that the marine bacteria, Pseudoalteromonas sp. and Halomonas sp. appeared from the 3rd batch; their intensities increased steadily and dominated the recycled b...
The Deepwater Horizon Oil Spill was the largest oil spill in USA history releasing approximately 4.9 million barrels of crude oil into the Gulf of Mexico. Soon after the spill started, tar balls and other forms of weathered oil appeared in large numbers on beaches in Mississippi and Alabama. In this study, we analyzed tar balls for total aerobic bacterial (TAB) counts and also for the presence of Vibrio vulnificus, a human pathogen known to be abundant in the Gulf Coast environment and capable of causing severe wound infections by contact with contaminated surfaces. Our results showed that TAB counts were significantly higher in tar balls than in sand and seawater collected at the same location. In addition, V. vulnificus numbers were 10? higher in tar balls than in sand and up to 100? hig...
Aim of the study was to evaluate the use of home-grown pea seeds as protein source in diets for lactating sheep. Two isonitrogenous and isoenergetic diets were fed to 12 mid-lactating Delle Langhe ewes for 73 days. The animals were fed with 1.5kg alfalfa hay and either 0.7kg commercial concentrate (control group, C) or 0.6kg home-grown pea-barley mix (experimental group, PB). The main protein sources in the supplements were sunflower meal and soybean seeds for C group, and pea seeds for PB group. Milk yield was recorded and milk samples were analysed for fat, protein, lactose, casein, solids non-fat, somatic cell count, total bacterial count and fatty acids. Results showed that milk yield and gross composition were not significantly affected by the supplementation types. Differences were i...
The Deepwater Horizon Oil Spill was the largest oil spill in USA history releasing approximately 4.9 million barrels of crude oil into the Gulf of Mexico. Soon after the spill started, tar balls and other forms of weathered oil appeared in large numbers on beaches in Mississippi and Alabama. In this study, we analyzed tar balls for total aerobic bacterial (TAB) counts and also for the presence of Vibrio vulnificus, a human pathogen known to be abundant in the Gulf Coast environment and capable of causing severe wound infections by contact with contaminated surfaces. Our results showed that TAB counts were significantly higher in tar balls than in sand and seawater collected at the same location. In addition, V. vulnificus numbers were 10× higher in tar balls than in sand and up to 100× hig...
Abstract The present study aims to investigate physico-chemical and bacterial characteristics of Nasser Lake water and houses drinking water, as well as fish cultures and its wastewater, in three villages west of Lake Nasser, Egypt. Fifteen representative water samples (Nasser Lake, different drinking water, fish cultures, and wastewater sources) were collected from three villages (Garf Hussein, Bashaier, and Kalabsha) in the west of Lake Nasser. Physico-chemical, total viable counts, and bacterial qualification of water were achieved. The obtained results indicated that the produced water, supposed to be for domestic use in the three villages, contained all the tested organisms. The investigated water samples of the lake and drinking water in the selected three villages are supposed to be...
Antimicrobial efficacy of cryotreatment against Enterococcus faecalis in root canals.
The purpose of this investigation was to evaluate intracanal bacterial reduction by cryotreatment using a dental instrument equipped with a duct and connected to a cryogenic fluid source. A total of 86 roots were infected with Enterococcus faecalis and incubated. After incubation, the contaminated roots were divided into 3 study groups: 35 roots irrigated with 2 ml of a 5% sodium hypochlorite (NaOCl) solution, 35 roots irrigated with 2 ml of a 5% NaOCl solution and further treated with cryo and 10 roots irrigated with 2 ml of saline solution, plus positive and negative controls. Subsequent to each irrigation treatment, the residual bacterial colonies were counted. The use of cryo-instrumentation in association with NaOCl irrigation significantly reduced the number of Ent. faecalis (pApplied Microbiology © 2012 The Society for AppliedMicrobiology. PMID:23106670
Objective The aim of this study was to determine the profiles of periodontopathogenic bacteria in a Chinese population using quantitative real-time polymerase chain reaction (qRT-PCR). Materials and methods Twenty-four periodontally healthy Chinese subjects and 60 patients with chronic periodontitis (CP) were enrolled in this cross-sectional study. qRT-PCR was used to quantify Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis, and Prevotella intermedia as well as total bacterial counts from 252 samples collected from the saliva, supragingival plaque, and subgingival plaque of all 84 subjects. Results The detection frequency of A. actinomycetemcomitans was less than 50%. F. nucleatum was detected in all subjects and CP patients had higher bacterial loa...
The utility of cerebrospinal fluid parameters in the early microbiological assessment of meningitis
The measurement of cerebrospinal fluid (CSF) protein, glucose, and white cell count (WCC) is an essential part of the initial examination of CSF. The aim of this study was to determine the utility of CSF parameters in assessing the likely aetiological agent. A total of 2290 CSF samples from a 13-year period were retrospectively reviewed. The initial parameters were compared between bacterial, viral, and cryptococcal meningitis and cases where no pathogen was found. A protein concentration of <600 mg/L and a WCC <90 x 10^6/L were found to be optimal cut-offs for excluding bacterial meningitis. A WCC of <25 x 10^6/L was found to be optimal for excluding cryptococcal meningitis and a WCC of <10 x 10^6 for excluding viral meningitis. Decreased glucose concentration was found to be a poor indic...
Effects of small-diameter silver nanoparticles on microbial load in cow milk
Controlling bacterial growth in fluid milk is of economic interest, and supplemental methods to stop or reduce bacterial growth before and during the cooling chain may be valuable. Silver is effective in controlling growth of single-celled organisms, but has no effect on tissue cells. Smaller diameter (6-8nm) silver nanoparticles were produced, with purity over 99.99% (no chemical reaction used in the process), by using a terminated gas condensation principle. The first trial investigated effects of time, temperature, and accelerating voltages on total aerobic bacteria count in control milk and milk treated with silver nanoparticles. Metal braids were coated with silver nanoparticles using 3 accelerating voltages, 0, 100, and 200V, the results of which indicated that the braids coated usin...
Diversity of Vibrionaceae associated with Ruditapes decussatus hatchery in Tunisia
The diversity of Vibrionaceae was investigated in a Ruditapes decussatus hatchery located in the Tunisian coastal marine waters. Quantitative study of the bacterial flora, conducted in different compartments of the hatchery, revealed that the total bacterial count (TVC) and the presumptive Vibrio (PVC) increased during the summer, due to the rise of temperature. The treatment of breeders with chloramphenicol (8?mg/l/day) for 4?days and the usage of open circuit sea water as a larva-rearing technique significantly reduced the density of the presumptive Vibrio in larva. Vibrionaceae strains were isolated on TCBS agar plates and identified using some bacteriological tests (?API 20 E strips? standardized micro-method for biochemical identification, vibriostatic agent O/129, growth at different...
Microbial populations on hides of grazing steers in a forage-based production system in Uruguay.
The objective of the study was to evaluate the microbiological status of hides of grazing steers in a typical forage-based system in Uruguay. The study was conducted on a single farm with samples taken on 3 days during the spring of 2007. Four anatomical hide sites (perineum area, flank, back, and shoulder) of 10 steers were individually swabbed each sampling day at the farm environment (n = 120). Each sample was analyzed by the Laboratorio Tecnológico del Uruguay for aerobic plate counts (APC), total coliform counts (TCC), and Escherichia coli counts (ECC). Mean log values for APC, TCC, and ECC on external animal hide surfaces, across all sampling sites, were 5.52, 1.89, and 1.70 log CFU/cm2, respectively. There were no significant differences among bacterial counts from the four hide surface locations. Mean log values for APC, TCC, and ECC were 1.49, 1.15, and 1.12 log CFU/cm2 lower, respectively, on sampling day 2 than on sampling day 3. Microbial populations on hides of grazing steers are highly variable and dependent on climatic and environmental conditions. To our knowledge this is the first study published evaluating the hygienic conditions of grazing livestock operations in Uruguay and their potential implications on the red meat chain. PMID:18810879
Volatilization of fluorescein mercuric acetate by marine bacterial from Minamata Bay
Some bacteria that live in a mercury-polluted environment are resistant to mercury compounds. A majority of these mercury-resistant bacterial have been found to volatilize organic as well as inorganic mercury compounds into elemental mercury vapor by means of their enzymes. One compound, fluorescein mercuric acetate (FMA) has long been in use as a disinfectant in hospitals; yet, there has been little definitive information on bacterial resistance to this compound. Minamata Bay has been heavily polluted by mercury, which has caused methylmercury poisoning in humans, called Minamata disease. Sediments from the Bay still contain high concentrations of mercury. The percentage of mercury-resistant bacteria in the total bacterial count is higher in these sediments than in those of other marine environments. FMA-pollution, however, has not been reported. Research into the mechanism of bacterial resistance to FMA will not only add to our general understanding of the ability of certain bacteria to resist mercury, but will also help in defining the role bacteria play in the mercury cycle of a mercury-polluted environment. The purpose of the present study is to determine the mechanism of resistance to FMA of the FMA-resistant bacteria living in the Bay.
This study reports for the first time the induction of immunity in Antheraea assama Ww larvae against bacterial flacherie. In silkworms group of disease caused by bacteria are collectively called "flacherie." This refers to the flaccid condition of the larvae due to the infections of bacterial strains pathogenic to muga silkworm. Antibacterial activity against pathogenic Pseudomonas aeruginosa AC-3 causing flacherie, was induced by injection of heat-killed cells of the same strain. Experiments on larval survivability and viable cell count revealed peak immune response on third day. Comparison of the amount of food ingested, excreta produced and larval weight of the saline-injected control, live bacteria-challenged larvae and heat-killed bacteria-injected larvae "(vaccinated)" confirmed the development of immunity against bacterial infection in the "vaccinated" set. The haemolymph of A. assama larvae was analyzed for proteins associated with bacterial infection. Out of the total 32 detected proteins, eleven (A1-2, A15-20, A22-23, and A29) were constitutively synthesized in both the control and live bacteria-injected larvae. Four inducible proteins A4, A9-10, and A21 were detected in the haemolymph of the live bacteria-injected larvae. Synthesis of rest of the proteins varied between the control and their live bacteria-injected counterparts. General protein profile of "vaccinated" larvae injected with live bacteria were found to be similar to that of the saline-injected control. PMID:15172214
This work compared the effect of challenge with Vibrio tapetis, the etiologic agent of brown ring disease (BRD) in clams, and other bacterial strains on defence-related factors in four bivalve species: Ruditapes philippinarum (highly susceptible to BRD), R. decussatus (slightly susceptible to BRD), Mercenaria mercenaria and Crassostrea virginica (both non-susceptible to BRD). Results show that bacterial challenge modulated defence-related factors, namely total and differential haemocyte counts, percentage of viable haemocytes, and lysozyme activity, both in haemolymph and extrapallial fluid. Injection with bacteria induced a response that was dependent upon the bacterial and bivalve species investigated, and upon the site of inoculation: external (pallial cavity), pseudo-internal (extrapallial space), or internal compartment (adductor muscle). The most conspicuous changes were systematically measured in R. philippinarum injected with V. tapetis, indicating a bacterial pathogenicity particular to the host in which it causes a specific disease syndrome. Alterations of defence-related factors were maximal in haemolymph of clams injected with V. tapetis in the muscle, and in the extrapallial fluid when the bacteria were injected into the pallial or the extrapallial cavity. Resistance to the development of the BRD symptom was not related to the extent of the haemocyte reaction measured following in vivo challenge. PMID:16005645
Observations on biofilm formation in industrial air-cooling units
Observations on biofilm formation in industrial air-cooling units were made over a 60-day operational period. Methods employed included: epifluorescent direct counts of water and slime samples, enumeration of culturable bacteria in water and slime samples, and ultrastructural observations of microbial attachment to formvar coated grids and epoxy resin blocks. Acridine orange direct counts and culturable counts of bacteria in water samples remained constant over the 60-day cycle, while culturable counts in slime samples increased with time. Interfering fluorescent materials present in the slime made accurate direct counts difficult to obtain. Initial increases in numbers of bacteria on formvar coated grids and culturable counts of slime samples were positively correlated with time. However, after 14 days, the formvar deteriorated and direct transmission electron microscopic bacterial counts could no longer be obtained. Submersion of epoxy resin blocks, especially those with pitted surfaces, provided an excellent method for the observation of bacterial attachment and colonization. 21 references, 3 figures.
Two 16S rRNA gene clone libraries (KF and KS) were constructed using two soil samples (K7s and K8s) collected near Kafni Glacier, Himalayas. The two libraries yielded a total of 648 clones. Phyla Actinobacteria, Bacteroidetes, Chloroflexi Firmicutes, Proteobacteria, Spirochaetae, Tenericutes and Verrucomicrobia were common to the two libraries. Phyla Acidobacteria, Chlamydiae and Nitrospirae were present only in KF library, whereas Lentisphaerae and TM7 were detected only in KS. In the two libraries, clones belonging to phyla Bacteroidetes and Proteobacteria were the most predominant. Principal component analysis (PCA) revealed that KF and KS were different and arsenic content influenced the differences in the percentage of OTUs. PCA indicated that high water content in the K8s sample results in high total bacterial count. PCA also indicated that bacterial diversity of KF and KS was similar to soils from the Pindari Glacier, Himalayas; Samoylov Island, Siberia; Schrimacher Oasis, Antarctica and Siberian tundra. The eleven bacterial strains isolated from the above two soil samples were phylogenetically related to six different genera. All the isolates were psychro-, halo- and alkalitolerant. Amylase, lipase and urease activities were detected in the majority of the strains. Long chain, saturated, unsaturated and branched fatty acids were predominant in the psychrotolerant bacteria. PMID:21918795
Microbial succession in a compost-packed biofilter treating benzene-contaminated air.
Air artificially contaminated with increasing concentrations of benzene was treated in a laboratory scale compost-packed biofilter for 240 days with a removal efficiency of 81-100%. The bacterial community in the packing material (PM) at different heights of the biofilter was analysed every 60 days. Bacterial plate counts and ribosomal intergenic spacer analysis (RISA) of the isolated strains showed that the number of cultivable aerobic heterotrophic bacteria and the species diversity increased with benzene availability. Identification of the isolated species and the main bands in denaturing gradient gel electrophoresis (DGGE) profiles from total compost DNA during the treatment revealed that, at a relatively low volumetric benzene load (1.2VBLVBL value (24.8 g m(-3) (PM) h(-1)) ensuring the maximum elimination capacity of the biofilter (20.1 g m(-3) (PM) h(-1)), strains affiliated to the genus Rhodococcus dominated the microflora, followed by beta-proteobacteria comprising the genera Bordetella and Neisseria. Under these conditions, more than 35% of the isolated strains were able to grow on benzene as the sole carbon source. Comparison of DGGE and automated RISA profiles of the total community and isolated strains showed that a complex bacterial succession occurred in the reactor in response to the increasing concentrations of the pollutant and that cultivable bacteria played a major role in benzene degradation under the adopted conditions. PMID:16502043
Comparisons of ruminal fermentation characteristics and microbial populations in bison and cattle.
Ruminal microbial populations, fermentation characteristics, digestibility, and liquid flow rates in two ruminally cannulated bison and two ruminally cannulated Hereford steers fed a prairie hay diet were compared. No significant differences in anaerobic bacterial counts, volatile fatty acid concent...
Changes in water and sediment bacterial community structure in a lake receiving acid mine drainage
Heterotrophic bacterial communities in water and sediment samples from 3 sites in a reservoir receiving acid mine drainage water were studied for stress-related changes due to the pollution. Acridine range direct counts and heterotrophic plate counts were made. Community similarity and numbers of acid and metal tolerant isolates were determined. Bacterial diversity was lower in water polluted by acid mine drainage and there were reduced numbers of heterotrophic bacteria.
Effect of correctly using alcohol-based hand rub in a clinical setting.
We evaluated hand antisepsis in clinical practice at Aarhus University Hospital in Skejby, Denmark. The rate of compliance with the correct use of alcohol-based hand rub exceeded 55% of all routine clinical procedures observed. With the correct use of alcohol-based hand rub by hospital staff, bacterial counts were reduced by 90% before and 82% after a clinical procedure; with incorrect use, the bacterial counts were reduced by 60% before and 54% after a clinical procedure. PMID:18754741
Diarrhoea is a hallmark of HIV infections in developing countries, and many diarrhoea-causing agents are often transmitted through water. The objective of the study was to determine the diversity and antibiotic susceptibility profiles of bacterial organisms isolated from samples of household drinking-water consumed by HIV-infected and AIDS patients. In the present study, household water stored for use by HIV-positive patients was tested for microbial quality, and isolated bacterial organisms were analyzed for their susceptibility profiles against 25 different antibiotics. The microbial quality of water was generally poor, and about 58% of water samples (n=270) were contaminated with faecal coliforms, with counts varying from 2 colony-forming unit (CFU)/100 mL to 2.4x10? CFU/100 mL. Values of total coliform counts ranged from 17 CFU/100 mL to 7.9x10?/100 mL. In total, 37 different bacterial species were isolated, and the major isolates included Acinetobacter lwoffii (7.5%), Enterobacter cloacae (7.5%), Shigella spp. (14.2%), Yersinia enterocolitica (6.7%), and Pseudomonas spp. (16.3%). No Vibrio cholerae could be isolated; however, V. fluvialis was isolated from three water samples. The isolated organisms were highly resistant to cefazolin (83.5%), cefoxitin (69.2%), ampicillin (66.4%), and cefuroxime (66.2%). Intermediate resistance was observed against gentamicin (10.6%), cefepime (13.4%), ceftriaxone (27.6%), and cefotaxime (29.9%). Levofloxacin (0.7%), ceftazidime (2.2%), meropenem (3%), and ciprofloxacin (3.7%) were the most active antibiotics against all the microorganisms, with all recording less than 5% resistance. Multiple drug resistance was very common, and 78% of the organisms were resistant to three or more antibiotics. Education on treatment of household water is advised for HIV-positive patients, and measures should be taken to improve point-of-use water treatment as immunosuppressed individuals would be more susceptible to opportunistic infections. PMID:23082625
Induction of prophages from deep-subseafloor bacteria
Summary The deep-subseafloor biosphere harbours a major part of the total microbial biomass on Earth. However, how life and death in this environment are regulated is not yet understood. While organisms from higher trophic levels appear to be absent, viruses might be a factor for microbial mortality. In this study, we found an increasing ratio between viral and total cell counts with depth in deep-subseafloor sediments recovered during Leg 201 of the Ocean Drilling Program. A phylogenetically diverse culture collection from corresponding sediment layers was tested for the presence of inducible prophages. A treatment by mitomycin C as inducing agent indicated the presence of prophages in 46% of the bacterial isolates. Different morphotypes of myoviruses and siphoviruses were detected by tra...
Sponges can filter large amounts of water, which exerts an important grazing impact on free bacteria, an important component of the diet of sponges. We examined the accumulation of bacteria in the Demospongiae (Hymeniacidon perlevis). Analyses were performed on homogenates from unstarved and starved sponges in seawater from their sampling site (the Ionian Sea). Culturable heterotrophic bacteria (22 degrees C), total culturable bacteria (37 degrees C) and vibrios densities were measured on marine agar 2216, plate count agar and TCBS agar, respectively. Total and fecal coliforms, as well as fecal streptococci, were determined by the most probable number method (MPN). H. perlevis was able to accumulate all of the six microbiological groups. Bacterial groups differed in their resistance to digestion by H. perlevis. Our data suggest that H. perlevis may accumulate, remediate and metabolize bacteria and that they may be employed as a useful bioindicator and bioremediator. PMID:20434181
Sponges can filter large amounts of water, which exerts an important grazing impact on free bacteria, an important component of the diet of sponges. We examined the accumulation of bacteria in the Demospongiae (Hymeniacidon perlevis). Analyses were performed on homogenates from unstarved and starved sponges in seawater from their sampling site (the Ionian Sea). Culturable heterotrophic bacteria (22degreeC), total culturable bacteria (37degreeC) and vibrios densities were measured on marine agar 2216, plate count agar and TCBS agar, respectively. Total and fecal coliforms, as well as fecal streptococci, were determined by the most probable number method (MPN). H. perlevis was able to accumulate all of the six microbiological groups. Bacterial groups differed in their resistance to digestion...
The 16S rDNA PCR-DGGE and rpoB quantitative PCR (RQ-PCR) techniques were used to evaluate the effects of dietary flavomycin and florfenicol on the autochthonous intestinal microbiota of hybrid tilapia. The fish were fed four diets: control, dietary flavomycin, florfenicol and their combination. After 8?weeks of feeding, 6 fish from each cage were randomly chosen for the analysis. The total number of intestinal bacteria was determined by RQ-PCR. The results showed that dietary antibiotics significantly influenced the intestinal microbiota and dramatically reduced the intensity of total intestinal bacterial counts. The intensity of some phylotypes (EU563257, EU563262 and EU563255) were reduced to non-detectable levels by both dietary antibiotics, while supplementation of florfenicol to the d...
Abstract Various polysaccharides extract from marine algae to increase the non-specific immune system in crustacean. In this study, effects of hot-water extract on total haemocyte count, total plasma protein, Phagocytic activity, bacterial clearance efficiency and bactericidal activity while the shrimp Fenneropenaeus indicus (10.122.18-g) were immersed in seawater (40-g-L-1 and 250.8-C) containing hot-water extract of brown algae Padina boergesenii at 100, 300 and 500-mg-L-1 for 1-4-h, were investigated. These parameters increased significantly (P<0.05) when the shrimp were immersed in seawater containing hot-water extract at 100-mg-L-1 after 3-h and 300 and 500-mg-L-1 after 2-h. Fenneropenaeus indicus that were immersed in hot-water extract at 300 and 500-mg-L-1 had significantly increase...
The purpose of the study was to determine the effects of two nights of sleep deprivation with or without energy restriction on immune indices at rest and in response to cold exposure. On three randomised occasions ten males slept normally [mean (SD): 436 (21)?min?night?1; CON], were totally sleep-deprived (SDEP), or were totally sleep-deprived and 90% energy-restricted (SDEP?+?ER) for 53?h. After 53?h (1200?h) participants performed a seated cold air test (CAT) at 0.0?C until T re decreased to 36.0?C. Circulating leucocyte counts, neutrophil degranulation, stress hormones and saliva secretory IgA (S-IgA) were determined at 0?h, 24?h, 48?h, pre-CAT, post-CAT, 1-h and 2-h post-CAT. One night on SDEP increased bacterially stimulated neutrophil degranulation (21%, P?P?T re decreased to 35.9 (0...
Radiation decontamination of poultry viscera
Application of gamma radiation for decontamination of poultry viscera was examined. Exposure to a dose of 20 kGy rendered the viscera sterile (<1 CFU/10 g tissue), while 5 and 10 kGy reduced the total bacterial count by 4 and 6 log{sub 10} cycles, respectively, eliminating the coliforms to <1 CFU/g of tissue. Analysis of organoleptic and biochemical parameters [proximate composition, total volatile basic nitrogen (TVBN), lipid peroxidation (TBARS value), and levels of TCA soluble peptides and proteolytic enzyme] showed that gamma irradiation (20 kGy) followed by storage at 4 deg. C for 62 days induced no significant change (except lipid peroxidation) in the acceptability of poultry viscera. However, storage at ambient temperature (26 {sup o}C) produced enhanced levels of TVBN and TCA soluble products accompanied by higher drip loss. Activities of proteolytic enzymes, except acid protease, did not show any significant change during post-irradiation storage at either temperature.
Effects of calf diet, antioxidants, packaging type and storage time on beef steak storage
The effect of basal dietary supplemented with vegetable oils plus vitamin E (sunflower, soybean, linseed and a basal diet control), type of packaging (MAP or vacuum), addition of natural antioxidant (grape seed, rosemary) and storage time (0, 7, 14 and 21days) on lipid oxidation, color stability, vitamin E content, and total aerobic bacterial counts in steaks of Longissimus thoracis was studied. The triple interaction dietxtimexpackaging affected oxidative stability, redness and yellowness of the meat. TBARS values did not increase with time in vacuum-packaged samples for all dietary treatments. However, samples from MAP and control showed the highest TBARS values after 21days of storage (0.72mg MDA/kg of meat, P<0.05). Both exogenous antioxidant extracts and MAP maintained low total aerob...
Objective: The objective of this study was to evaluate the microbial quality of the well water used as a drinking source in urban and rural households. Methods: A total of 80 household well water samples were analyzed by the multiple fermentation tube method to determine the presumptive coliform count/most probable number of coliforms, and the isolates were identified using standard procedures, followed by susceptibility testing. Results: Fecal indicator organisms, including Escherichia coli and Enterococcus spp. were isolated from 22 (27.5%) samples, and the majority (92.5%) of the water sources were contaminated with coliforms. A total of 170 bacterial isolates were obtained, including coliforms (70%), Enterococcus spp. (1.8%) and saprophytes (28.2%). A significant number of isolates wer...
The purpose of this study was to evaluate the bulk tank milk (BTM) quality of 9 East Tennessee dairy farms and to determine its relationship with selected quality milk parameters. Bulk tank milk samples (n=1,141) were collected over a 42-mo period (June 2006 through November 2009) from farms, based on their preliminary incubation count (PIC) history. Parameters of BTM quality evaluated in this study included somatic cell count (SCC), standard plate count (SPC), PIC, laboratory pasteurization count (LPC), Staphylococcus spp. count, Streptococcus spp. count, and coliform count. Strong correlations between SPC and Streptococcus spp. counts (0.72) and between SPC and PIC (0.70) were found. However, moderate correlations were seen among other milk quality parameters. In addition, seasonal variations for some milk quality parameters were noted. For example, milk quality parameters such as SCC, SPC, LPC, and coliform count were significantly higher in summer, whereas Streptococcus spp. counts were significantly higher in winter. No seasonal variation in PIC or Staphylococcus spp. counts was observed. Summarizing, results from this investigation showed the importance of using several bacterial counts (SCC, SPC, PIC, LPC, Streptococcus spp. count, Staphylococcus spp. count, and coliform counts) as simultaneous indicators of milk quality. PMID:22818441
Bacterial clearance in the intact and regenerating liver
The Kupffer cells in the liver play an important role in reticuloendothelial system (RES) function by clearing particulate matter and bacteria from the blood stream. While hepatocyte regeneration and function have been extensively studied following partial hepatectomy, little information is available concerning RES function in the regenerating liver. This study investigates hepatic RES function by evaluating bacterial clearance (live E. coli) in the intact and regenerating liver. Thirty-four young male Sprague Dawley rats were studied. Twenty-two animals underwent a standard 70% partial hepatectomy using ligature technique and 12 had a sham operation. Both groups of rats received 10(9) organism of TVS labeled E coli, intravenously at 24 hours, 72 hours, 2 1/2 weeks, and 6 weeks postoperatively. Rats were killed 10 minutes following injection and liver, lung, spleen, and kidney harvested, fixed, and radioactivity was determined using a scintillation spectrometer interfaced with a micro-computer counting the TVS radiolabel. The total organ count of trapped bacteria in liver in partially hepatectomized rats was lower than intact controls at 24 hours, but was similar at 72 hours, 2 1/2 weeks, and 6 weeks. Partial hepatectomy increased the amount of bacterial trapping in the lung at 24 hours and 72 hours and returned to normal at 2 1/2 weeks and 6 weeks. Splenic activity was increased following hepatectomy at 2 1/2 weeks. Renal clearance was increased at 72 hours and 2 1/2 weeks.
Prokaryotic Diversity in Aran-Bidgol Salt Lake, the Largest Hypersaline Playa in Iran
Prokaryotic diversity in Aran-Bidgol salt lake, a thalasohaline lake in Iran, was studied by fluorescence in situ hybridization (FISH), cultivation techniques, denaturing gradient gel electrophoresis (DGGE) of PCR-amplified fragments of 16S rRNA genes and 16S rRNA gene clone library analysis. Viable counts obtained (2.5-4×106 cells mL-1) were similar to total cell abundance in the lake determined by DAPI direct count (3-4×107 cells mL-1). The proportion of Bacteria to Archaea in the community detectable by FISH was unexpectedly high and ranged between 1:3 and 1:2. We analyzed 101 archaeal isolates and found that most belonged to the genera Halorubrum (55%) and Haloarcula (18%). Eleven bacterial isolates obtained in pure culture were affiliated with the genera Salinibacter (18.7%), Salicola (18.7%) and Rhodovibrio (35.3%). Analysis of inserts of 100 clones from the eight 16S rRNA clone libraries constructed revealed 37 OTUs. The majority (63%) of these sequences were not related to any previously identified taxa. Within this sampling effort we most frequently retrieved phylotypes related to Halorhabdus (16% of archaeal sequences obtained) and Salinibacter (36% of bacterial sequences obtained). Other prokaryotic groups that were abundant included representatives of Haloquadratum, the anaerobic genera Halanaerobium and Halocella, purple sulfur bacteria of the genus Halorhodospira and Cyanobacteria.
The effects of supercritical CO2 bubbling (SC-CO2) treatment on the inactivation of microorganisms in water prior to treatment at a municipal water filtering plant (untreated water) were investigated as a way to produce safe drinking water. The coliform bacterial count decreased concomitantly with increasing CO2/sample flow rate in the SC-CO2 treatment. In particular, coliform bacteria could not be detected at a CO2/sample flow rate greater than 55%. Also, the total bacterial count dropped rapidly at first stage and slowly at second stage in the SC-CO2 treatment. Upon observation of Escherichia coli before and after the SC-CO2 treatment with scanning electron microscopy and transmission electron microscopy, it was observed that the cells treated with SC-CO2 were shorter than untreated cells and that cytoplasm with low electronic density in the treated cells disappeared. In addition, four types of metabolic enzyme in E. coli cells were effectively inactivated by the SC-CO2 treatment. These results suggested that SC-CO2 treatment could effectively inactivate microorganisms in untreated water, and induce morphological changes and inactivate metabolic enzymes of E. coli cells.
Prokaryotic Diversity in Aran-Bidgol Salt Lake, the Largest Hypersaline Playa in Iran
Prokaryotic diversity in Aran-Bidgol salt lake, a thalasohaline lake in Iran, was studied by fluorescence in situ hybridization (FISH), cultivation techniques, denaturing gradient gel electrophoresis (DGGE) of PCR-amplified fragments of 16S rRNA genes and 16S rRNA gene clone library analysis. Viable counts obtained (2.5—4 × 106 cells mL-1) were similar to total cell abundance in the lake determined by DAPI direct count (3—4×107 cells mL-1). The proportion of Bacteria to Archaea in the community detectable by FISH was unexpectedly high and ranged between 1:3 and 1:2. We analyzed 101 archaeal isolates and found that most belonged to the genera Halorubrum (55%) and Haloarcula (18%). Eleven bacterial isolates obtained in pure culture were affiliated with the genera Salinibacter (18.7%), Salicola (18.7%) and Rhodovibrio (35.3%). Analysis of inserts of 100 clones from the eight 16S rRNA clone libraries constructed revealed 37 OTUs. The majority (63%) of these sequences were not related to any previously identified taxa. Within this sampling effort we most frequently retrieved phylotypes related to Halorhabdus (16% of archaeal sequences obtained) and Salinibacter (36% of bacterial sequences obtained). Other prokaryotic groups that were abundant included representatives of Haloquadratum, the anaerobic genera Halanaerobium and Halocella, purple sulfur bacteria of the genus Halorhodospira and Cyanobacteria.
Biofilms associated with poultry processing equipment.
Aerobic and Gram-negative bacteria were enumerated on non-metallic surfaces and stainless steel test pieces attached to equipment surfaces by swabbing and a mechanical dislodging procedure, respectively, in a South African grade B poultry processing plant. Changes in bacterial numbers were also monitored over time on metal test pieces. The highest bacterial counts were obtained from non-metallic surfaces such as rubber fingered pluckers and plastic defeathering curtains which exceeded the highest counts found on the metal surfaces by at least 1 log CFU cm-2. Gram-negative bacterial counts on all non-metallic surface types were at least 2 log CFU cm-2 lower than corresponding aerobic plate counts. On metal surfaces, the highest microbial numbers were obtained after 14 days exposure, with aerobic plate counts ranging from 3.57 log CFU cm-2 to 5.13 log CFU cm-2, and Gram-negative counts from 0.70 log CFU cm-2 to 3.31 log CFU cm-2. Scanning electron microscopy confirmed the presence of bacterial cells on non-metallic and metallic surfaces associated with poultry processing. Rubber 'fingers', plastic curtains, conveyor belt material and stainless steel test surfaces placed on the scald tank overflow and several chutes revealed extensive and often confluent bacterial biofilms. Extracellular polymeric substances, but few bacterial cells were visible on test pieces placed on evisceration equipment, spinchiller blades and the spinchiller outlet. PMID:8858863
Chicken litter is produced in large quantities from all types of poultry raising activities. It is primarily used for land application, thus it is essential to analyze its properties before it is released to the environment. The objective of this study is to compare the microbiological and chemical properties of litter generated from layer and broiler chickens reared under intensive and free-range production systems. The microbiological analysis consisted of the enumeration of total bacteria, total coliforms, Staphylococcus species, Salmonella species and Clostridium perfringens. Chicken litter from layers reared under intensive and free range systems showed lower mean total bacterial count than the litter collected from chicken broilers reared under either of the two systems (P = 0.0291). The litter from intensive layers had the lowest mean total coliform counts (P = 0.0222) while the lowest Staphylococcus species count was observed in the litter from free-range layers (P = 0.0077). The C. perfringens count was the lowest in chicken litter from intensively raised broilers and layers (P = 0.0001). The chemical properties of litter from the different chicken types and production systems were compared based on determination of pH, electrical conductivity, carbon, nitrogen, phosphorus, potassium, cadmium and zinc. Litter from free-range broilers showed the highest pH value (P = 0.0005); however, the electrical conductivity was higher in the litter from both intensive and free-range layers compared to the litter from both broiler production systems (P = 0.0117). Chicken litter from intensive systems had higher nitrogen content than litter from free-range systems (P = 0.0000). The total phosphorus was the lowest in free-range broiler litter (P = 0.0001), while the total potassium was the lowest in litter from intensively managed broilers (P = 0.0000). Zinc appeared higher in litter from layers compared to that from broilers (P = 0.0101). The cadmium content was higher in the litter from free-range broilers and layers compared to that in the litter from intensively managed systems (P = 0.0439). Staphylococcus species in the litter as well as cadmium concentrations seem to be the most critical parameters presenting risks on the environment and on human health. Based on the lowest coliform counts (an indication of water pollution), the high nutrient levels and the low cadmium values, litter from intensively managed layers appears as the most suitable for application on agricultural soils.
Microbiological survey of a South African poultry processing plant.
Bacterial populations associated with poultry processing were determined on neck skin samples, equipment surfaces and environmental samples by replicate surveys. Aerobic plate counts, Enterobacteriaceae counts, Enterobacteriaceae counts and Pseudomonas counts were performed by standard procedures and the prevalence of Listeria, presumptive Salmonella and Staphylococcus aureus determined. Statistically significant (P defeathering curtains, shackles and conveyor belts repeatedly showed aerobic plate counts in excess of 5.0 log CFU 25 cm-2. Aerobic plate counts of scald tank and spinchiller water were 2 log CFU ml-1 higher than those of potable water samples. Bacterial numbers of the air in the "dirty" area were higher than those of the "clean" area. Listeria, presumptive Salmonella and Staphylococcus aureus were isolated from 27.6, 51.7 and 24.1% of all product samples, respectively, and Listeria and Staphylococcus aureus were also isolated from selected equipment surfaces. PMID:7783001
Although it is known that Palk Bay sediments harbor diverse and novel bacteria with important ecological and environmental functions, a comprehensive view of their molecular diversity is still lacking. In the present study, bacterial diversity in Palk Bay sediments was characterized using the molecular method terminal-restriction fragment length polymorphisms (T-RFLP). The bacterial assemblages detected by T-RFLP analysis revealed that the nearshore sediment harbored high number of bacterial count, whereas the 2.5-m sediment harbored diverse and distinct bacterial composition with fine heterogeneity. The major bacterial groups detected in all the three sediment samples were Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria (including alpha (α), gamma (γ), delta (δ), and epsilon ...
Abstract in portuguese Avaliou-se o efeito da variação da qualidade do leite mediante acompanhamento de amostras provenientes de tanques refrigeradores. As 2.970 amostras foram obtidas de outubro/2005 a setembro/2006. Foram realizadas análises de composição, contagem de células somáticas (CCS) e contagem bacteriana total. As condições climáticas foram avaliadas pela temperatura e umidade do ar coletadas em estações meteorológicas distribuídas em todo o estado de São Paulo. No out (more) ono, ocorreram os maiores valores para gordura e proteína do leite, 3,65 e 3,21%, respectivamente. Para contagem de células somáticas, foi observado aumento no verão e contagem bacteriana na época da primavera. Foi identificada a influência da época do ano sobre o preço do leite pago dentro de um programa, com valor de bonificação máxima de 7,9% para o outono. Um dos mais importantes itens relacionados com a penalização foi a CCS, a qual pode interferir na qualidade dos produtos finais por meio de alteração da proporção de caseína/proteínas do soro. O efeito da CCS e o da época do ano devem ser considerados na formulação das tabelas de programas de pagamento. Abstract in english This study evaluated the variation of quality of bulk tank milk using 2,970 samples, collected from October 2005 to September 2006. Milk composition analyses, somatic cell count (SCC), and total bacterial count were performed. Climate conditions were evaluated by temperature and relative air humidity collected at meteorological stations throughout São Paulo state. Autumn season was related to the highest values for protein and fat, 3.65 and 3.21%, respectively. For somat (more) ic cell count, it was observed an increase in the count in the summer and for bacterial count in the spring. The influence of season on milk price was observed for dairy producers in a program, with maximum bonus of 7.9% in the autumn. One of the most important parameters related to penalty for lower quality of milk was SCC, since it can affect the quality of some dairies by the alteration of casein/whey protein proportion. Therefore, the effects of SCC and season should be considered into the process of formulation of tables for milk payment program.
The effect of storage at various temperatures on the bacterial community of a cooling-water sample and a tap-water sample was determined. Samples were stored at 4, 10, 20 and 30 degrees C for 24, 48, 72 and 216 h and the aerobic plate count and bacterial community structure of each were determined u...
The effect of transgenic Bt 176 maize on the rhizosphere bacterial community has been studied with a polyphasic approach by comparing the rhizosphere of Bt maize cultivated in greenhouse with that of its non transgenic counterpart grown in the same conditions. In the two plants the bacterial counts ...
Bulk water phase and biofilm growth in drinking water at low nutrient conditions
In this study, the bacterial growth dynamics of a drinking water distribution system at low nutrient conditions was studied in order to determine bacterial growth rates by a range of methods, and to compare growth rates in the bulk water phase and the biofilm. A model distribution system was used to quantify the effect of retention times at hydraulic conditions similar to those in drinking water distribution networks. Water and pipe wall samples were taken and examined during the experiment. The pipes had been exposed to drinking water at approximately 131C, for at least 385 days to allow the formation of a mature quasi-stationary biofilm. At retention times of 12 h, total bacterial counts increased equivalent to a net bacterial growth rate of 0.048 day1. The bulk water phase bacteria exhibited a higher activity than the biofilmbacteria in terms of culturability, cell-specific ATP content, and cell-specific leucine incorporation rate. Bacteria in the bulk water phase incubated without the presence of biofilmexhibited a bacterial growth rate of 0.30 day1. The biofilmwas radioactively labelled by the addition of 14C-benzoic acid. Subsequently, a biofilmdetachm ent rate of 0.013 day1 was determined by measuring the release of 14C-labelled bacteria of the biofilm. For the quasi-stationary phase biofilm, the detachment rate was equivalent to the net growth rate. The growth rates determined in this study by different independent experimental approaches were comparable and within the range of values reported in the literature. r 2002 Elsevier Science Ltd. All rights reserved.
A fluorescent filter method using the Bioplorer apparatus and a conventional standard plate count method were compared for microbial cell enumeration in soymilk. Soymilk samples were solubilized for filtration. The microbial cell count obtained using the Bioplorer method showed good correlation with that obtained by the standard plate count method. The results of this study showed that the Bioplorer method is a rapid and efficient method for enumeration of bacterial cells in soymilk.
Effect of Dietary Short-Chain Fructooligosaccharides on the Cecal Microflora in Gastrectomized Rats
Total gastric resection is known to lead to changes in the microflora in the whole gastrointestinal tract. Dietary short-chain fructooligosaccharides (Sc-FOS) have been shown to also induce a change in the microflora in the large bowel by promoting an increase in the numbers of Bifidobacterium and Lactobacillus which have beneficial effects on the host. In the present study, 4-week-old male Sprague-Dawley rats received total gastrectomy or laparotomy, and each of these surgically treated groups was randomly divided into two experimental diet groups and given a 7.5% Sc-FOS diet or control diet. Enumeration and identification of the cecal bacteria was performed by using selective and non-selective media. In the gastrectomized rats, the total bacterial count, and the counts of Bacteroidaceae and Enterobacteriaceae were higher than those in the sham-operated rats. Sc-FOS promoted an increase in the numbers of Bifidobacterium and Lactobacillus, In the rats fed on the Sc-FOS diet, the predominant type of bacteria was Lactobacillus and in the rats fed on the control diet, it was Bacteroidaceae irrespective of gastrectomy. We confirmed that both gastrectomy and dietary Sc-FOS changed the composition of cecal microflora in the rats. Dietary Sc-FOS in the gastrectomized rats increased the proportions of Lactobacillus relative to other types of bacteria to levels similar to those seen in healthy normal rats, and decreased the proportion of Bacteroidaceae.
Cans of three tomato paste brands (two of which are imported and one produced locally) showing defective or normal appearance were purchased from various retail outlets and analysed for microbial composition and pH values. Substantially higher total viable counts were observed in samples from defective cans but the lowest population was found in the local brand. Ratio of mesophilic to thermophilic micro-organisms increased in samples obtained from cans showing visible defects. Anaerobic spore counts were higher than the aerobic population in both normal and defective cans, but the counts varied with the brands. Four dominant bacterial genera (Bacillus, Clostridium, Lactobacillus and Leuconostoc) were isolated from the samples with the greater proportion being spore-formers. Percentage occurrence of Clostridium thermosaccharolyticum was appreciably higher in samples from defective cans while a preponderance of Lactobacillus occurred in samples from normal cans. Of the moulds isolated, Absidia and Aspergillus fumigatus showed a higher percentage in defective cans. pH values higher than the critical safe level of 4.6 were found in cans with visible defects and greater microbial diversity with higher microbial load was more often associated with these samples. Imported brands showed more undesirable microbial quality and pH values, making them potentially hazardous. PMID:9721645
To assess the microbiological quality and safety of export game meat; i) a total of 80 pooled meat samples for aerobic plate count (APC) and Enterobacteriaceae ii) water used in harvesting and processing for microbiological quality and iii) meat and rectal contents for Salmonella spp. and Shiga toxin Escherichia coli (STEC) were evaluated in 2009 and 2010. No differences (p>0.05) in the APCs were observed between the years, but the mean Enterobacteriaceae count for 2009 was 1.33±0.69log(10)cfu/cm(2) compared to 2.93±1.50log(10)cfu/cm(2) for 2010. Insignificant Heterotrophic Plate Count (HPC) levels were detected in 9/23 field water samples, while fecal bacterial (coliforms, Clostridium perfringens and enterococci) were absent in all samples. No Salmonella spp. was isolated and all E. coli isolates from meat were negative for STEC virulence genes (stx1, stx2, eae and hlyA), suggesting a negligible role by springbok in the epidemiology of STEC and Salmonella. PMID:22944735
Ten metalworking fluids (MWF) and seven water preparation basis samples (WPB) were taken from five industrial plants in Germany. Total cells (TCC) and colony forming units (CFU) were counted, strains were isolated and their 16S rRNA gene was sequenced. Additionally, DNA was extracted directly from the samples, and clone libraries of 16S rRNA genes were built and gene sequenced. TCC ranged from 7.6×10(4) TCC/mL MWF to 1.6×10(8) TCC/mL MWF, and from 4.6×10(2) TCC/mL WPB to 7.8×10(7) TCC/mL WPB. The CFU showed similar but often lower results. A total of 70 isolates and 732 clones were 16S rRNA gene sequenced and all isolates, as well as 183 of the nearly full length 16S rRNA of these clones, were gene sequenced. A total of 98 different genera were detected in all 17 samples. The number of genera within each sample varied highly, with 1-22 genera per sample. The dominant genera in MWF were Leucobacter, Desemzia, Sphingomonas and Wautersiella. From these, only Sphingomonas was detected in WPB as well. This study showed that MWF can harbour a high bacterial diversity, which differs significantly from the bacterial flora of the corresponding WPB. PMID:22609341
This study evaluated the effects of a commercial prebiotic, Immunogen, on feed utilization, growth rate, immunity promotion and carcass composition of the common carp Cyprinus carpio fingerlings. The fingerlings were adopted for 2 weeks and then reared in triplicate groups in 250-l tanks (n = 15 per tank with average initial weights of 11.12 ± 0.55 g). The fish fed on five isonitrogenous and isoenergetic experimental diets containing different levels of Immunogen (0, 0.5, 1, 1.5 and 2.5 g prebiotic/kg diet) to apparent satiation thrice a day for 8 weeks. Weight gain showed no differences among the groups fed different Immunogen levels. Both feed efficiency ratio and protein efficiency ratio significantly (p < 0.05) increased with increasing Immunogen levels from 0.5 to 1.5 g/kg diet. The highest protein content (p < 0.05) was found in the fish fed a diet containing 2.5 g/kg prebiotic. Haematological parameters and plasma total protein concentration were also significantly higher (p < 0.05) in the fingerlings fed diets containing 1.5 and 2.5 g/kg prebiotic in relation to the control. The control fish contained the highest mean of total bacterial counts. The lowest mean (p < 0.05) of total bacterial counts was observed in the fish fed the diet containing 2.5 g/kg Immunogen. The present study reveals that a dietary Immunogen supplementation from 1 to 1.5 g/kg is capable to improve the feed efficiency and growth performance of C. carpio fingerlings as well as their resistance to A. hydrophila infection. PMID:21707781
This study demonstrates the first use of matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) to trace the Invivo infection kinetics of the well known deadly pathogen Staphylococcus aureus in Swiss albino mice. The growth curve of the bacteria from the point of injection (200mL of bacterial suspension (10^8cfu/mL)) into the mouse blood till mortality (death) was periodically analyzed using the plate counting method and MALDI-MS. Bacterial counts of 10^3cfu/mL were observed in the log phase of the growth curve in the blood and 10^2cfu/mL were observed in the urine samples. Death occurred in the log phase of the growth curve, where the bacterial counts showed steady increase. In other cases, the bacteria counts started decreasing after 48h and by 96h the bacteria got tota...
Evaluation of procalcitonin and neopterin level in serum of patients with acute bacterial infection
Abstract in english BACKGROUND: Fever as a common presenting complaint in pediatric patients can be due to various causes. Differentiating bacterial infection from other causes is important because the prompt use of antibiotics is critical in bacterial infection. Traditional markers of infection such as BT and WBC count may be unspecific and culture may be late or absent. CRP and Procalcitonin (PCT) have been considered to evaluate the evolution of infections and sepsis in patients presentin (more) g with SIRS. Neopterin has also been proposed to aid in the diagnosis of bacterial infection. In this study, we compared the value of the serum PCT, neopterin level, and WBC count for predicting bacterial infection and outcome in children with fever. METHODS: 158 pediatric (2-120-month-old) patients suspected to have acute bacterial infection, based on clinical judgment in which other causes of SIRS were ruled out were included in the study. WBC count with differential was determined and PCT and neopterin levels were measured. RESULTS: PCT level was higher in bacterial infection and patients who were complicated or expired. CONCLUSION: Rapid PCT test is superior to neopterin and WBC count for anticipating bacterial infection, especially in ED where prompt decision making is critical. ABBREVIATIONS: BT, body temperature; WBC, white blood cell; PCT, procalcitonin; CRP, C-reactive protein; SIRS, systemic inflammatory response syndrome; ED, emergency department.
ABSTRACT: BACKGROUND: Bacterial blood stream infections constitute a significant public-health problem and it is an important cause of morbidity and mortality in HIV infected patients. Little is known in developing countries regarding salmonella bacteraemia among HIV patients. The purpose of this study was to determine the bacterial pathogens causing blood stream infection among febrile adults attending in a tertiary hospital North-Western, Tanzania. METHODS: A prospective cross-sectional study involving 346 consecutive, febrile adult patients admitted at Bugando Medical Centre was conducted. Demographic and other data were collected using standardized questionnaires. Blood culture was done followed by susceptibility testing using disc diffusion method. HIV testing was also performed as per Tanzania national algorithm and total white blood cell counts and CD4+ counts determined. RESULTS: Of 346 febrile adult patients 33 (9.5 %) had blood stream infections. The common isolates were Salmonella spp 13(39.4%), Escherichia coli 8 (24.2%), Streptococcus pneumonia 5(15.2%), Staphylococcus aureus 4(12.1%), Citrobacter spp 1(3%), Streptococcus pyogenes 1(3%) and Klebsiella pneumonia 1(3%). A total of 156 (45.1%) patients were HIV infected; of whom 12/156 (7.6%) were infected by no-typhoid Salmonella spp compared to 1/190 (0.5%) of non-HIV infected patients (RRR 11.2, p=0.029) infected with Salmonella typhi. HIV infected patients with bacteraemia had significantly lower CD4+ count than those without bacteraemia (median 28 vs. 88 cells/ml, p=0.01). Patients with salmonella bacteraemia had significantly lower median of WBC than those with non-salmonella as well as those without bacteraemia (median, 3.6 vs. 17.5 vs. 9.8x109, p=0.0001). All Salmonella spp were sensitive to ceftriaxone and imipenem, while being 84%, 69.2%, 38% and 8% resistant to chloramphenicol, ampicillin, sulphamethaxazole/trimethoprim and ciprofloxacin respectively. Predictors of mortality were HIV infection (OR 2.3, p=0.006), Glasgow coma score of less than 15 (OR 3.4, p=0.0001) and night sweats (OR 2.4, p=0.014). CONCLUSION: Non-typhoid Salmonella spp that are highly resistant to common antibiotics are predominant cause of bacterial blood stream infection among HIV patients attending Bugando Medical Centre. Continuous surveillance and intervention strategies should be put in place to monitor and manage cases of bloodstream infections in HIV-positive patients in Mwanza, Tanzania. PMID:23075077
Summary The biochemical and storage properties of African yam bean (Sphenostylis stenocarpa) yoghurt-like product were evaluated. Milk extracted from the bean flour using hot water was supplemented with 4% milk protein concentrate (MPC), 0.15% dairy calcium (DC) and 0.5% gelatine (G) (singly or in combination). The milk was fermented with Streptococcus thermophilus and Lactobacillus delbrueckii spp bulgaricus at 43 degreeC for 3-5 h. Supplemented African yam bean (AYB) yoghurts had a gel-like consistency unlike the control (unsupplemented) sample. Total solids, protein, fat, ash, lactic acid bacterial count, lightness (L-value) and viscosity were improved by supplementation. Riboflavin and antioxidants were reduced; macroelements and thiamine were increased by 0.71-15.6% and 16.7%, respect...
Effects of ionizing energy treatment on the quality of ginseng products
Pre-established doses were applied to Panax ginseng powders for determining the effects of {gamma}-irradiation on the quality of samples from the microbiological, some physico-chemical and organoleptic points of view. Irradiation at 5 kGy was sufficient not only to reduce total bacterial counts (1.28 x 10{sup 5}/g) by about 3 orders of magnitude but to eliminate coliforms, yeast and molds during three months of storage at 30{sup 0}C and 50-60% RH. An established dose of 5 kGy caused little change in pH, acidity, TBA number, pigments, color, and overall acceptability of the sample, however there was a significant change in color and appearance of the irradiated sample at 10 kGy where all microorganisms were destroyed. (author).
A whey-predominant formula induces fecal microbiota similar to that found in breast-fed infants
To compare the effects of a whey-predominant infant formula and breast milk on the gut microbiota, growth, and tolerance of infants, we conducted an open, prospective, parallel-group study in healthy newborn infants. A total of 60 infants were enrolled, and 55 completed the study. Of the 55 infants, 21 were breast-fed and 34 were fed a whey-predominant study formula that had low phosphate concentration (31 mg/100 kcal), was reduced in protein (1.8 g/100 kcal or 0.43 g/kJ), had lactose as the sole carbohydrate source, and had an amino acid profile and buffering capacity similar to that of human milk. At 30 and 60 days of age, fecal bacterial counts were determined using fluorescence in situ hybridization and culture plating, and growth and digestive tolerance were evaluated. There were no d...
Evaluation of somatic cell count thresholds to detect subclinical mastitis in Gyr cows
The objectives of this study were (1) to determine the sensitivity (Se) and specificity (Sp) of somatic cell count (SCC) thresholds to identify subclinical mastitis in Gyr cows caused by major and minor pathogens; (2) to study the effects of month of sampling, rear or front mammary quarters, herd, intramammary infection (IMI), and bacterial species on SCC at quarter level; and (3) to describe the prevalence of IMI in Gyr cows in commercial dairy herds. In total, 221 lactating Gyr cows from 3 commercial dairy farms were selected. Milk samples were collected from individual quarters once a month for 1 yr from all lactating cows for SCC and bacteriological analysis. Mammary quarters were considered the experimental units and the SCC results were log10-transformed. Four SCC thresholds (100, 20...
Egyptian mango seeds were collected as wastes from local fruit processing units, the kernels were separated and dried. The antioxidant and antimicrobial activities of mango seed kernel extract and oil were investigated. The results indicated that combination of both mango seed kernel extract and oil had optimum antioxidant potency higher than each one alone. Addition of 400ppm methanol extract and 5% mango seed kernel oil increased the oxidative stability of sunflower oil incubated at ambient temperature as well as sunflower oil during frying. Moreover, both extract and oil improved the stability and quality characteristics of fresh and stored potato chips. On the other hand, mango seed kernel extract reduced total bacterial count, inhibited coliforms growth, showed remarkable antimicrobia...
Nine tuna dumpling products were purchased at nine retail markets in southern Taiwan. Occurrence of biogenic amines, histamine-forming bacteria, and adulteration of pork and poultry were determined. This study showed the high contents of aerobic plate count, total coliform and Escherichia coli in tested tuna dumpling products. Average content of various biogenic amines in all tested samples was less than 2.0mg/100g. Fifteen histamine-producing bacterial strains isolated from tested samples produced 8.7-466ppm of histamine in trypticase soy broth supplemented with 1.0% l-histidine (TSBH). Assay of multiplex polymerase chain reaction (PCR) revealed adulteration rates were 88.9% (8/9) and 33.3% (3/9) for pork and poultry, respectively, in tuna dumpling. In addition, six samples of tuna dumpli...
Quantification of bioavailable chlortetracycline in pig feces using a bacterial whole-cell biosensor
Bacterial whole-cell biosensors were used to measure the concentration of chlortetracycline (CTC) in the feces of pigs. In this study, the Escherichia coli biosensor used has a detection limit of 0.03 mg/kg CTC in pig feces. The tetracycline concentration was correlated with the appearance and maintenance of fecal coliform bacteria resistant to tetracycline. Initially, large quantities of water-extractable CTC were excreted from the pigs and measurable amounts were detected even at 30 days after treatment cessation. This led to a sharp rise in the number of tetracycline resistant coliform bacteria in the feces, to within the same order of magnitude as the total coliform count. The high level of tetracycline resistance was maintained in spite of the declining concentration of tetracycline. (C) 2002 Elsevier Science B.V. All rights reserved.
Summary Effect of turmeric and lemongrass essential oils (Eos) and their mixture on quality of green mussel stored at 4-C was investigated. The mixture of 0.25% turmeric and 0.25% lemongrass Eos could lower microbiological and chemical deterioration of mussel as evidenced by the lower microbial counts, total volatile base, ammonia, trichloroacetic acid-soluble peptide contents and thiobarbituric acid-reactive substances, compared with the control (P--0.05). It indicated that a mixture of turmeric and lemongrass Eos in mussel showed synergistic effect on the retardation of bacterial growth and lipid oxidation. However, samples treated with 0.5% lemongrass oil exhibited the higher likeness score for odour and flavour, compared with the samples treated with other Eos throughout the storage of...
Reducing SO2 in fresh pork burgers by adding chitosan.
The use of 0.02 or 0.05% chitosan is proposed to reduce from 450 to 150 mg kg(-1) the SO(2) required to preserve pork burgers aerobically packed and stored at 2 °C for up to 21 days under retail display conditions. The effects of chitosan and/or sulfite addition and the storage time were determined in fresh (color deterioration, lipid oxidation, pH, total viable counts, Escherichia coli and coliforms, Salmonella, appearance and odor) and cooked (appearance, odor, flavor and texture) burgers. The addition of either 0.02 or 0.05% chitosan was not detected by sensory analysis, and extended the shelf life of low-SO(2) burgers from 7 to 14 days. Chitosan enhanced the preservative effects of sulfite at a low dose, acting on the main causes of meat deterioration (bacterial spoilage, color stability and lipid oxidation), and provided good sensory properties to fresh and cooked pork burgers. PMID:22749538
Summary Changes in microbiological and biochemical quality of clams (Ruditapes decussatus) subjected to low doses of gamma irradiation (0.5 and 1 kGy) were investigated during alive storage, at 5 degreeC. The mortality rate was significantly lower for irradiated clams compared with the control. In the same way, ammonia content was lower for irradiated clams (especially 1 kGy irradiated group). Considerable levels of total mesophiles, coliforms, staphylococcus, faecal streptococcus and Escherichia coli were detected in the control and irradiation had immediately reduced these charges; all bacteria studied experienced a 1- to 3-log reduction following 1 kGy irradiation. At the last day of storage, irradiated groups showed a noticeable reduction in the bacterial counts, whereas the mesophiles...
Abstract Potential bacterial pathogens are found in the airways in several diseases that are associated with neutrophilic inflammation. The aim of this study was to characterize subjects with stable asthma, with no symptoms of respiratory infection, to assess whether key potentially pathogenic bacteria were present in significant quantities in the airways and to correlate this with the pattern of airway inflammation and oxidative stress. Subjects with stable asthma (n = 115) and healthy controls (n = 8) underwent clinical assessment, including hypertonic saline challenge combined with sputum induction. A significant load of potentially pathogenic bacteria (> 106 cfu/mL) was cultured from the sputum of 17 (15%) subjects with stable asthma and was associated with higher total cell counts, pr...
Raw vegetables are usually contaminated by a variety of microorganisms. Post-harvest microflora differs considerably, reflecting environmental and handling conditions and might compromise the safety of the product and the consumer's health. Dipping or rinsing of vegetables in bleach solution is a common practice employed by the retailers and catering companies in order to minimize the initial bacterial load on the surface of vegetables. Rinsing or dipping vegetables in water saturated with ozone could be an alternative environmental friendly and safer process since no harmful by-products or residues are formed. Lettuce (Lactuca sativa) and bell peppers (Capsicum annuum) dipped in chlorinated water (20 ppm) resulted in 1 log decrease of the total microbial count in the first 15 min. Immersi...
This study was conducted to elucidate relationships among various phenolic fractions in, and methane (CH4) emissions from, tropical plants when incubated in ruminal fluid in vitro. As a second objective, principal component analysis (PCA) was tested for its utility in screening plants for their ability to reduce CH4 formation at simultaneously acceptable nutritional quality. Leaves from 27 tropical plants were analyzed for their nutritional composition and various phenolic fractions. They were incubated in vitro using the Hohenheim gas test method. Variables measured after 24h of incubation were total gas and CH4 production, and pH, ammonia, bacterial and protozoal counts, as well as short-chain fatty acids in the incubation fluid. In vitro organic matter (OM) digestibility was computed by...
Summary Six strains of novel bacteria were isolated from profundal sediment of Lake Constance, a deep freshwater lake in Germany, by direct dilution of the sediment in mineral agar medium containing a background lawn of the hydrogen-scavenging Methanospirillum hungatei as a syntrophic partner. The numbers of colony-forming units obtained after incubation for more than 2 months were in the same range as those of total bacterial counts determined by DAPI staining (up to 108 cells per millilitre) suggesting that these organisms were dominant members of the community. Identical dilution series in the absence of methanogenic partners yielded numbers that were lower by two to three orders of magnitude. The dominant bacteria were isolated in defined co-culture with M. hungatei, and were further c...
Cytometric methods for measuring bacteria in water: advantages, pitfalls and applications
Rapid detection of microbial cells is a challenge in microbiology, particularly when complex indigenous communities or subpopulations varying in viability, activity and physiological state are investigated. Flow cytometry (FCM) has developed during the last 30?years into a multidisciplinary technique for analysing bacteria. When used correctly, FCM can provide a broad range of information at the single-cell level, including (but not limited to) total counts, size measurements, nucleic acid content, cell viability and activity, and detection of specific bacterial groups or species. The main advantage of FCM is that it is fast and easy to perform. It is a robust technique, which is adaptable to different types of samples and methods, and has much potential for automation. Hence, numerous FCM...
Volatile compounds released during ripening in Italian dried sausage
A commercial production was analysed at six stages during ripening. Water content, pH and bacterial counts were followed, and volatile compounds from sausages were extracted by dynamic headspace sampling and analysed by gas chromatography/mass spectrometry. Total concentrations of all classes increased during ripening. Pepper compound concentrations peaked in the middle of the ripening period. Lipid oxidation products increased especially towards the end of ripening, in particular, the compounds 2-heptanol, 1-octen-3-ol, 2-heptanone and 2-nonanone. Surface moulds probably caused 4-heptanone to appear late in the processing. Benzeneacetaldehyde was absent in fresh mince, but increased to become one of the most abundant volatiles. Compounds from carbohydrate catabolism disappeared during the processing.
Improvement of microbiological safety of sous-vide meals by gamma radiation
Experimental batches of smoked-cured pork in stewed beans sauce were inoculated with spores of psychrotrophic Bacillus cereus, more heat and radiation resistant than spores of non-proteolytic C. botulinum. After vacuum packaging, the meals were treated with combinations of pasteurizing heat treatments and gamma irradiation of 5kGy. Prior and after treatments, and periodically during storage at 10°C, total aerobic and total anerobic viable cell counts, and selectively, the viable cell counts of B. cereus and sulphite-reducing clostridia have been determined. The effects of the treatment order as well as addition of nisin to enhance the preservative efficiency of the physical treatments were also studied. Heat-sensitization of bacterial spores surviving irradiation occurred. The quality-friendly sous-vide cooking in combination with this medium dose gamma irradiation and/or nisin addition increased considerably the microbiological safety and the keeping quality of the meals studied. However, approx. 40% loss of thiamin content occurred as an effect of combination treatments, and adverse sensorial effects may also limit the feasible radiation doses or the usable concentrations of nisin.
Improvement of microbiological safety of sous-vide meals by gamma radiation
Experimental batches of smoked-cured pork in stewed beans sauce were inoculated with spores of psychrotrophic Bacillus cereus, more heat and radiation resistant than spores of non-proteolytic C. botulinum. After vacuum packaging, the meals were treated with combinations of pasteurizing heat treatments and gamma irradiation of 5 kGy. Prior and after treatments, and periodically during storage at 10 deg. C, total aerobic and total anerobic viable cell counts, and selectively, the viable cell counts of B. cereus and sulphite-reducing clostridia have been determined. The effects of the treatment order as well as addition of nisin to enhance the preservative efficiency of the physical treatments were also studied. Heat-sensitization of bacterial spores surviving irradiation occurred. The quality-friendly sous-vide cooking in combination with this medium dose gamma irradiation and/or nisin addition increased considerably the microbiological safety and the keeping quality of the meals studied. However, approx. 40% loss of thiamin content occurred as an effect of combination treatments, and adverse sensorial effects may also limit the feasible radiation doses or the usable concentrations of nisin.
Hemocytic immune responses triggered by CpG ODNs in shrimp Litopenaeus vannamei.
CpG oligodeoxynucleotides (CpG ODNs), also called bacterial DNA or synthetic oligodeoxynucleotides, can induce apparent immunity protection against various pathogens, and they are widely used as functional immunostimulant or vaccine adjuvant in mammals. In the present study, CpG-rich plasmid pUC57-CpG was constructed and employed to stimulate the shrimp Litopenaeus vannamei, and the total hemocyte count, percentage of apoptotic hemocytes, regeneration of circulating hemocytes, the ability of phagocytosis and generation of reactive oxygen species (ROS) were measured to reveal the possible protection mechanism of CpG ODNs. After the injection of pUC57-CpG, the total hemocyte count significantly decreased (p < 0.01) to 2.56 × 10(7) cell/mL at the first day post stimulation, while the apoptosis increased (p < 0.01), which was 1.72-fold of that in control group. At the same time, the regeneration of circulating hemocytes fluctuated in a similar trend, and a significant increase was observed at the first day post stimulation. The phagocytotic activity including the percentage of phagocytosis and phagocytotic index, experienced an upward tend during the whole experimental period and the ROS level increased by 22% (p < 0.05) compared to that in the control group at first day post stimulation. These results together suggested that pUC57-CpG could promote the apoptosis and regeneration of circulating hemocytes, and enhance the phagocytosis and ROS production, which might contribute to the boosted immunity against the infection of pathogens. PMID:23063537
Hydrocarbon phytoremediation by Cyperus laxus Lam. growing on perlite and inoculated with hydrocarbon-degrading microorganisms was evaluated. Total petroleum hydrocarbons (TPH) were extracted from weathered soil (60.7 g of TPH kg(-1) of dry soil) and spiked on perlite at initial concentration of 5 g of TPH kg(-1) of dry perlite. Phenological characteristics, total microbial viable counts, hydrocarbon degraders and residual hydrocarbons were determined through 180 days of culture. Phenological characteristics of inoculated plants were improved as compared with non-inoculated plants: root biomass was 1.6 times greater, flowering time was reduced (13%), and the number of inflorescences was 1.5 times higher. The rhizospheric bacterial and fungi counts were higher for planted treatments (inoculated and not inoculated) than for unplanted pots. The maximum phytoremediation rate (0.51 mg of TPH g(-1) of dry plant d(-1)) for inoculated plants was reached at 60 days of culture, and was two times higher than for non-inoculated plants (55% TPH removal). Similar hydrocarbon phytoremediation extent values for inoculated (90%) and non-inoculated (85%) plants were obtained at 180 days of culture. The present study demonstrated that mutual benefits between C. laxus and inoculated hydrocarbon-degrading microorganisms are improved during phytoremediation. It is pertinent to note that this is the first report of hydrocarbon phytoremediation by Cyperus laxus Lam., a native plant growing in highly contaminated swamps. PMID:15763093
The present study was undertaken to investigate the culturable aerobic faecal microflora of mink from newborn until adulthood with emphasis on the potential pathogens Escherichia coli and beta-haemolytic coagulase positive staphylococci. Rectal swabs were taken from 10 healthy dams and their offspring on seven mink farms throughout the production season and a semi-quantitative enumeration of total E. coli and haemolytic E. coli, beta-haemolytic streptococci, beta-haemolytic coagulase positive staphylococci, total lactic acid bacteria, and enterococci was carried out in all samples using selective and non-selective media. Aerobic bacteria were cultured from close to 100% of the samples throughout the survey. Prevalence of E. coli isolates varied between 70 and 90% of the samples throughout the survey with a small decline at the end of the study period. The highest bacterial counts were found among recently weaned kits or kits in the early growth period (P <0.0012). Lactic acid bacteria and enterococci were isolated from more than 90% of all samples, while ?-haemolytic staphylococci were isolated from 20 to 70% of the samples. While ?-haemolytic staphylococci were dominant from birth and during the nursing period, counts of staphylococci gradually decreased during the nursing period and were outnumbered by E. coli during the growth season.
Plankton studies in a mangrove environment III: bacteriological analysis of waters in Cananéia
Abstract in portuguese As águas da região do mangue de Cananéia foram analisadas bacteriológicamente, com o objetivo de estabelecer seu grau de contaminação. As contagens aeróbicas variaram significativamente nas várias épocas, locais e marés, com um máximo de 13.000 bactérias/ml e um mínimo de 21/ml, ao passo que as contagens de coliformes mostraram variação significativa somente segundo os diversos locais com um máximo de 1.600 e um mínimo de 3/ml. O grupo Pseudomonas/Achromo (more) bacter abrangeu a mais alta percentagem da flora total com cerca de 60%. As características bioquímicas das linhagens deste grupo são mais sacarolíticas do que proteolíticas, certamente devido ao grande número de diatomáceas presentes. Abstract in english Waters of the mangrove swamp at Cananeia were analysed bacteriologically aiming the determination of the degree of bacterial contamination. Aerobic counts varied significantly by season, tide and station with the highest of 13,000 and the lowest of 21/ml while coliform counts showed significant variation only by station with the highest of 1,600 and the lowest of 3 per ml. Pseudomonas-Achromobacter group comprised the highest percentage of the total flora at the level of (more) around 60%. The biochemical characteristic of the strains of this group are more saccharolytic than proteolytic, certainly due to the great number of diatoms present.
Dissolved oxygen as an indicator of bioavailable dissolved organic carbon in groundwater
Concentrations of dissolved oxygen (DO) plotted vs. dissolved organic carbon (DOC) in groundwater samples taken from a coastal plain aquifer of South Carolina (SC) showed a statistically significant hyperbolic relationship. In contrast, DO-DOC plots of groundwater samples taken from the eastern San Joaquin Valley of California (CA) showed a random scatter. It was hypothesized that differences in the bioavailability of naturally occurring DOC might contribute to these observations. This hypothesis was examined by comparing nine different biochemical indicators of DOC bioavailability in groundwater sampled from these two systems. Concentrations of DOC, total hydrolysable neutral sugars (THNS), total hydrolysable amino acids (THAA), mole% glycine of THAA, initial bacterial cell counts, bacterial growth rates, and carbon dioxide production/consumption were greater in SC samples relative to CA samples. In contrast, the mole% glucose of THNS and the aromaticity (SUVA254) of DOC was greater in CA samples. Each of these indicator parameters were observed to change with depth in the SC system in a manner consistent with active biodegradation. These results are uniformly consistent with the hypothesis that the bioavailability of DOC is greater in SC relative to CA groundwater samples. This, in turn, suggests that the presence/absence of a hyperbolic DO-DOC relationship may be a qualitative indicator of relative DOC bioavailability in groundwater systems.
The antimicrobial and anticariogenic properties of a copper varnish (experimental mixture of Doc's Best Red Copper cement and Copalite varnish, Cooley and Cooley, Ltd, Houston, TX, USA: designated in this study as "Copper Seal") on the root surface were evaluated in an in vitro microbial caries model. Fifty-six human root specimens were prepared from anterior teeth and randomly divided into four groups: Groups 1 and 3-Copper Seal; Group 2-chlorhexidine varnish, the positive control (Cervitec, Ivolcar Vivadent, Schaan, Liechtenstein) and Group 4-a negative control that received no treatment. The varnishes were painted in Groups 1, 2 and 3, then visually removed after 24 hours in Group 1. The specimens were demineralized in a microbial caries model for five days. Plaque was collected from the specimens to obtain bacterial colonization numbers, then the specimens were sectioned and analyzed for lesion extent using Confocal Laser Scanning microscopy. There were no significant differences (p>0.05) among the four groups in terms of bacterial count. Regarding caries lesion development, the group with copper varnish visually removed (Group 1) and the non-treated group (Group 4) had significantly greater total area caries lesions and total lesion fluorescence than the copper varnish without removal group (Group 3) and the chlorhexidine group (Group 2). Therefore, it was concluded that copper and chlorhexidine varnishes have anticariogenic effects on root surfaces, as tested in this model. PMID:18435187
Impact of commonly used agrochemicals on bacterial diversity in cultivated soils.
The effects of three selected agrochemicals on bacterial diversity in cultivated soil have been studied. The selected agrochemicals are Cerox (an insecticide), Ceresate and Paraquat (both herbicides). The effect on bacterial population was studied by looking at the total heterotrophic bacteria presence and the effect of the agrochemicals on some selected soil microbes. The soil type used was loamy with pH of 6.0-7.0. The soil was placed in opaque pots and bambara bean (Vigna subterranean) seeds cultivated in them. The agrochemicals were applied two weeks after germination of seeds at concentrations based on manufacturer's recommendation. Plant growth was assessed by weekly measurement of plant height, foliage appearance and number of nodules formed after one month. The results indicated that the diversity index (Di) among the bacteria populations in untreated soil and that of Cerox-treated soils were high with mean diversity index above 0.95. Mean Di for Ceresate-treated soil was 0.88, and that for Paraquattreated soil was 0.85 indicating low bacterial populations in these treatment-type soils. The study also showed that application of the agrochemicals caused reduction in the number of total heterotrophic bacteria population sizes in the soil. Ceresate caused 82.50% reduction in bacteria number from a mean of 40 × 10(5) cfu g(-1) of soil sample to 70 × 10(4) cfu g(-1). Paraquat-treated soil showed 92.86% reduction, from a mean of 56 × 10(5) cfu g(-1) to 40 × 10(4) cfu g(-1). Application of Cerox to the soil did not have any remarkable reduction in bacterial population number. Total viable cell count studies using Congo red yeast-extract mannitol agar indicated reduction in the number of Rhizobium spp. after application of the agrochemicals. Mean number of Rhizobium population numbers per gram of soil was 180 × 10(4) for the untreated soil. Cerox-treated soil recorded mean number of 138 × 10(4) rhizobial cfu g(-1) of soil, a 23.33% reduction. Ceresate- and Paraquat-treated soils recorded 20 × 10(4) and 12 × 10(4) cfu g(-1) of soil, respectively, representing 88.89% and 93.33% reduction in Rhizobium population numbers. Correspondingly, the mean number of nodules per plant was 44 for the growth in untreated soil, 30 for the plant in the Cerox-treated soil, 8 for the plant in Paraquat-treated soil and 3 for the plant in Ceresate-treated soil. The study has confirmed detrimental effect of insecticide on bacterial populations in the soil. Total heterotrophic counts, rhizobial counts as well as the number of nodules of all samples taken from the chemically treated soils were all low as compared to values obtained for the untreated soil. However, the effect of the insecticide was minimal in all cases as compared to the effects of the herbicides on the soil fauna. Indiscriminate use of agrochemicals on farms can therefore affect soil flora and subsequently food production. PMID:23100773
Background: Pollen information is indispensable for allergic individuals and clinicians. This study aimed to develop forecasting models for the total annual count of airborne pollen grains based on data monitored over the last 20 years at the Mie Chuo Medical Center, Tsu, Mie, Japan. Methods: Airborne pollen grains were collected using a Durham sampler. Total annual pollen count and pollen count from October to December (OD pollen count) of the previous year were transformed to logarithms. Regression analysis of the total pollen count was performed using variables such as the OD pollen count and the maximum temperature for mid-July of the previous year. Results: Time series analysis revealed an alternate rhythm of the series of total pollen count. The alternate rhythm consisted of a cyclic alternation of an "on" year (high pollen count) and an "off" year (low pollen count). This rhythm was used as a dummy variable in regression equations. Of the three models involving the OD pollen count, a multiple regression equation that included the alternate rhythm variable and the interaction of this rhythm with OD pollen count showed a high coefficient of determination (0.844). Of the three models involving the maximum temperature for mid-July, those including the alternate rhythm variable and the interaction of this rhythm with maximum temperature had the highest coefficient of determination (0.925). Conclusions: An alternate pollen dispersal rhythm represented by a dummy variable in the multiple regression analysis plays a key role in improving forecasting models for the total annual sugi pollen count.
Discovery and development of anti-infectives at bayer: a personal view. Part III: fluoroquinolones
Background Catheter-associated urinary tract infection (CAUTI) is a common nosocomial device-associated infection. It is now recognized that the high infection rates were caused by the formation of biofilm on the surface of the catheters that decreases the susceptibility to antibiotics and results in anti-microbial resistance. In this study, we performed an in vitro test to explore the mechanism of biofilm formation and subsequently conducted a multi-center clinical trial to investigate the efficacy of CAUTI prevention with the application of JUC, a nanotechnology antimicrobial spray. Methods Siliconized latex urinary catheters were cut into fragments and sterilized by autoclaving. The sterilized sample fragments were randomly divided into the therapy and control group, whereby they were sprayed with JUC and distilled water respectively and dried before use. The experimental standard strains of Escherichia coli (E. coli) were isolated from the urine samples of patients. At 16 hours and 7 days of incubation, the samples were extracted for confocal laser scanning microscopy. A total of 1,150 patients were accrued in the clinical study. Patients were randomized according to the order of surgical treatment. The odd array of patients was assigned as the therapy group (JUC), and the even array of patients was assigned as the control group (normal saline). Results After 16 hours of culture, bacterial biofilm formed on the surface of sample fragments from the control group. In the therapy group, no bacterial biofilm formation was observed on the sample fragments. No significant increase in bacterial colony count was observed in the therapy group after 7 days of incubation. On the 7th day of catheterization, urine samples were collected for bacterial culture before extubation. Significant difference was observed in the incidence of bacteriuria between the therapy group and control group (4.52% vs. 13.04%, p CAUTI in a hospital setting was demonstrated in both in vitro and clinical studies. PMID:7927829
Evaluation of free-stall mattress bedding treatments to reduce mastitis bacterial growth
Bacterial counts were compared in free-stall mattresses and teat ends exposed to 5 treatments in a factorial study design on 1 dairy farm. Mattresses in five 30-cow groups were subjected to 1 of 5 bedding treatments every other day: 0.5 kg of hydrated limestone, 120 mL of commercial acidic conditioner, 1 kg of coal fly ash, 1 kg of kiln-dried wood shavings, and control (no bedding). Counts of coliforms, Klebsiella spp., Escherichia coli, and Streptococcus spp. were lowest on mattresses bedded with lime. Mattresses bedded with the commercial acidic conditioner had the next lowest counts for coliforms, Klebsiella spp., and Streptococcus spp. Wood shavings and the no-bedding control had the highest counts for coliform and Klebsiella spp. Compared with wood shavings or control, fly ash reduced the counts of coliforms, whereas for the other 3 bacterial groups, the reduction was not always significant. Streptococcus spp. counts were greatest in the control group and did not differ among the shavings and fly ash groups. Teat swab results indicated that hydrated lime was the only bedding treatment that significantly decreased the counts of both coliforms and Klebsiella spp. There were no differences in Streptococcus spp. numbers on the teats between any of the bedding treatments. Bacterial populations grew steadily on mattresses and were generally higher at 36 to 48 h than at 12 to 24 h, whereas bacterial populations on teats grew rapidly by 12 h and then remained constant. Hydrated lime was the only treatment that significantly reduced bacterial counts on both mattresses and teat ends, but it caused some skin irritation.
SUMMARY The prevalence of asthma in developing countries is lower than in developed countries. Viral, bacterial and parasitic infections may be associated with this discrepancy. The relationship between parasitic infection and asthma prevalence is not clear. Previous controversial data have demonstrated that parasitic infection may either predispose or protect against the development of asthma. The aim of this study is to determine whether infection with Angiostrongylus costaricensis (A. costaricensis) decreases inflammatory lung response to ovalbumin (OVA) in mice. Seven BALB/c mice were infected with A. costaricensis by orogastric gavage (10 larvae/mouse) on day (D) 0. The mice were immunized against OVA by intraperitoneal injection on D 5 and D 12 and received an intranasal OVA challenge (40 micro L) on D 15 and D 17. On D 19 bronchoalveolar lavage (BAL) was performed. Six BALB/c mice (control group) were immunized with OVA using the same protocol, but were not infected with A. costaricensis. Interleukin (IL)-1beta and IL-6 levels were measured in the BAL fluid by using commercial ELISA assays. Total cell counts and differential cell counts were performed in the BAL fluid samples. The group infected with A. costaricensis had lower total cell count in the BAL fluid when compared with the control group (0.11 x 10(6)cells/mL and 0.3 x 10(6)cells/mL, respectively; P = 0.013). BAL fluid IL-1beta levels in the infected group were significantly lower than in the control group (P = 0.008). IL-6 levels in BAL fluid were not different between the groups studied. We conclude that Angiostrongylus costaricensis infection in mice decreases pulmonary inflammatory response to OVA. PMID:15279626
Urbanization and industrialization has increased the strength and qualities of municipal sewage in Bangalore, India. The disposal of sewage into natural water bodies became a serious issue. Byramangala reservoir is one such habitat enormously polluted in South India. The water samples were collected from four hotspots of Byramangala tank in 3 months. The biochemical oxygen demand (BOD) and bacterial counts were determined. The fecal coliforms were identified by morphological, physiological, and biochemical studies. The antibiotics sensitivity profiling of isolated bacteria were further carried out. We have noticed that a high content of BOD in the tank in all the 3 months. The total and fecal counts were found to be varied from 1.6?×?10(6) to 8.2?×?10(6)?colony forming unit/ml and >5,500/100 ml, respectively. The variations in BOD and total count were found to be statistically significant at p?>?0.05. Many pathogenic bacteria were characterized and most of them were found to be multidrug resistant. Salmonella showed resistance to cefoperazone, cefotaxime, cefixime, moxifloxacin, piperacillin/tazobactam, co-trimoxazole, levofloxacin, trimethoprim, and ceftazidime. Escherichia coli showed resistance to chloramphenicol, trimethoprim, co-trimoxazole, rifampicin, and nitrofurantoin while Enterobacter showed resistant to ampicillin, cefepime, ceftazidime, cefoperazone, and cefotaxime. Klebsiella and Shigella exhibited multiple drug resistance to conventional antibiotics. Staphylococcus showed resistance to vancomycin, methicillin, oxacillin, and tetracycline. Furthermore, Salmonella and Klebsiella are on the verge of acquiring resistance to even the strongest carbapenems-imipenem and entrapenem. Present study revealed that Byramanagala tank has become a cesspool of multidrug-resistant "superbugs" and will be major health concern in South Bangalore, India. PMID:23114918
Organic-rich subsurface marine sediments were taken by gravity coring up to a depth of 10?m below seafloor at six stations from the anoxic Black Sea and the Benguela upwelling system off Namibia during the research cruises Meteor 72-5 and 76-1, respectively. The quantitative microbial community composition at various sediment depths was analyzed using total cell counting, catalyzed reporter deposition - fluorescence in situ hybridization (CARD-FISH) and quantitative real-time PCR (Q-PCR). Total cell counts decreased with depths from 10(9) to 10(10)?cells/mL at the sediment surface to 10(7)-10(9)?cells/mL below one meter depth. Based on CARD-FISH and Q-PCR analyses overall similar proportions of Bacteria and Archaea were found. The down-core distribution of prokaryotic and eukaryotic small subunit ribosomal RNA genes (16S and 18S rRNA) as well as functional genes involved in different biogeochemical processes was quantified using Q-PCR. Crenarchaeota and the bacterial candidate division JS-1 as well as the classes Anaerolineae and Caldilineae of the phylum Chloroflexi were highly abundant. Less abundant but detectable in most of the samples were Eukarya as well as the metal and sulfate-reducing Geobacteraceae (only in the Benguela upwelling influenced sediments). The functional genes cbbL, encoding for the large subunit of RuBisCO, the genes dsrA and aprA, indicative of sulfate-reducers as well as the mcrA gene of methanogens were detected in the Benguela upwelling and Black Sea sediments. Overall, the high organic carbon content of the sediments goes along with high cell counts and high gene copy numbers, as well as an equal abundance of Bacteria and Archaea. PMID:22319518
Multiple Loci Are Associated with White Blood Cell Phenotypes
White blood cell (WBC) count is a common clinical measure from complete blood count assays, and it varies widely among healthy individuals. Total WBC count and its constituent subtypes have been shown to be moderately heritable, with the heritability estimates varying across cell types. We studied 1...
The nematicidal effect of some bacterial biofertilizers on Meloidogyne incognita in sandy soil
Abstract in english In a greenhouse experiment, the nematicidal effect of some bacterial biofertilizers including the nitrogen fixing bacteria (NFB) Paenibacillus polymyxa (four strains), the phosphate solubilizing bacteria (PSB) Bacillus megaterium (three strains) and the potassium solubilizing bacteria (KSB) B. circulans (three strains) were evaluated individually on tomato plants infested with the root-knot nematode Meloidogyne incognita in potted sandy soil. Comparing with the uninoculat (more) ed nematode-infested control, the inoculation with P. polymyxa NFB7, B. megaterium PSB2 and B. circulans KSB2, increased the counts of total bacteria and total bacterial spores in plants potted soil from 1.2 to 2.6 folds estimated 60 days post-inoculation. Consequently, the inoculation with P. polymyxa NFB7 increased significantly the shoot length (cm), number of leaves / plant, shoot dry weight (g) / plant and root dry weight (g) / plant by 32.6 %, 30.8 %, 70.3 % and 14.2 %, respectively. Generally, the majority treatments significantly reduced the nematode multiplication which was more obvious after 60 days of inoculation. Among the applied strains, P. polymyxa NFB7, B. megaterium PSB2 and B. circulans KSB2 inoculations resulted in the highest reduction in nematode population comparing with the uninoculated nematode-infested control. They recorded the highest reduction in numbers of hatched juveniles/root by 95.8 %, females/root by 63.75 % and juveniles/1kg soil by 57.8 %. These results indicated that these bacterial biofertilizers are promising double purpose microorganisms for mobilizing of soil nutrients (nitrogen, phosphate and potassium) and for the biological control of M. incognita.
Abstract in portuguese Desejando colher informações sobre os aspectos bacteriológicos da indústria pesqueira da região sul do Brasil, com o objetivo de verificar onde e como poderia ser melhorada a situação vigente em relação à qualidade do pescado fresco, foram estudadas as condições microbiológicas existentes na pesca de arrasto de alto-mar e de parelhinhas de sol-a-sol, pesca com traina e pesca da baleia, assim como na água de lavagem, gelo e caixas de madeira utilizadas no aco (more) ndicionamento e manipulação do pescado. A pesquisa foi levada a efeito por meio de contagens totais de bactérias aeróbicas e em meio de extrato-de-peixe/peptona/agar, e contagem de bactérias coliformes em meio de agar/bile/vermelho-violeta, usando o método do número-mais-provável. O pescado capturado pelas parelhinhas apresentou nos locais de pesca, contagens de 10(5) - 10(7) bactérias por cm² de superfície da pele, mantendo nível quase idêntico no porto de descarga, com presença constante de bactérias coliformes. O peixe de arrasto de alto-mar demonstrou ter um número de bactérias igual a 10³ por cm² de superfície da pele, elevando-se a 10(4) - 10(6) ou números mais altos, no porto de descarga. Na pesca de traineira e da baleia o número de bactérias contadas atingir a 10(5) - 10(6) por ocasião da descarga. O número de bactérias das condições ambientes demonstrou ser alto: 10(5) - 10(6) bactérias por cm² da superfície do convés, 10(5) - 10(6) por cm² da superfície interna das caixas de madeira, 10(5) - 10(6) por ml de gelo derretido e 10³ - 10(4) por ml da água de lavagem retirada do canal de Santos, com presença constante de bactérias coliformes. São discutidos e sugeridos alguns métodos para melhorar as condições bacteriológicas acima mencionadas. Recomenda-se o uso da clorotetraciclina pelo método de imersão ou como aditivo ao gelo, cloração e filtração da água do canal para fins de lavagem e uso de caixas mais limpas para o acondicionamento do peixe. Abstract in english In order to obtain information on bacteriological aspects of the South Brazilian fish industry, with the object of finding out where and how to improve the actual situation for the better quality of fresh fish, microbiological conditions in short distance trawling, long distance trawling, purse-seining, whaling, wash-water, ice and wooden fish boxes, were studied by means of total aerobic counts on peptone-fish-extract-agar and coliform bacterial counts on violet-red-bile (more) -agar and by the most probable number method. In short distance trawling, fish at capture showed 10(5) - 10(7) level of bacterial counts per cm² of skin surface, and an almost equal level at landing with ordinary presence of coliform bacteria. In long distance trawling, bacterial count at capture was 10³ per cm² of skin surface and at landing, 10(4) - 10(6) or higher. In purse-seining and whaling, 10(5) - 10(6) level contamination was obtained at landing. Fishery environmental conditions showed rather high bacterial counts of 10(5) - 10(6) per cm² of deck surface, 10(5) - 10(6) per cm² of used wooden fish boxes (inside surface), 10(5) - 10(6) per ml of melted ice, and 10³ - 10(4) per ml of wash-water from canal, with the usual presence of coliform bacteria. Some methods to improve the above mentioned bacteriological conditions were discussed. The use of chlortetracycline in immersion method or as an additive to ice, chlorination and filtration of canal water for washing purpose, and the use of cleaner fish boxes are recommended.
Effects of small-diameter silver nanoparticles on microbial load in cow milk.
Controlling bacterial growth in fluid milk is of economic interest, and supplemental methods to stop or reduce bacterial growth before and during the cooling chain may be valuable. Silver is effective in controlling growth of single-celled organisms, but has no effect on tissue cells. Smaller diameter (6-8 nm) silver nanoparticles were produced, with purity over 99.99% (no chemical reaction used in the process), by using a terminated gas condensation principle. The first trial investigated effects of time, temperature, and accelerating voltages on total aerobic bacteria count in control milk and milk treated with silver nanoparticles. Metal braids were coated with silver nanoparticles using 3 accelerating voltages, 0, 100, and 200V, the results of which indicated that the braids coated using 100V (AgNP100) were optimal. The AgNP100 particles were effective at all treatment temperatures and durations except for 10h, which indicated that the treated milk could be used after 10h for other dairy products such as yogurt, which require microbial activity. The second experiment investigated the effects of silver nanoparticles on counts of yeasts and molds, coliform bacteria, Escherichia coli, and Staphylococcus aureus in cow milk by treating milk with AgNP100 braids at 22 °C for 1h. Inductively coupled plasma mass spectrometry analyses indicated that the maximum amount of silver found in the AgNP100-treated milk was 6.1?g/L, which is below the safety limits. Counts in milk samples containing the nanoparticle-coated braids were lower for all yeasts and molds and bacteria investigated compared with the control milk samples, which were kept under the same conditions but without the braids. The differences were significant for coliforms, Escherichia coli, and Staphylococcus aureus but not for yeasts and molds, although ranking of the counts (AgNP100 milk. Silver nanoparticles inhibited microbial growth and may be useful in complementing the cooling chain and the thermal processes. These results warrant more research on the sensory properties and long-term safety of the use of silver nanoparticles in dairy products. PMID:22365195
The antibiotic protein synthesis inhibitor chloramphenicol specifically blocked the incorporation of (35 S) sulfate into the residue protein of two marine bacteria, Pseudomonas halodurans and Alteromonas luteo-violaceus. Simultaneous inhibition of total protein synthesis occurred, but incorporation of 35 S into low-molecular-weight organic compounds continued. A. luteo-violaceus rapidly autolyzed, with similar reduction in cell counts, total culture protein and cellular sulfur, whereas P. halodurans remained viable. Treatment with chloramphenicol, growth during nitrogen and carbon limitation, and the carbon and energy sources used for growth did not alter the sulfur content of P. halodurans protein. The mean value (1.09%, by weight), representing a wide variety of environmentally relevant growth conditions, was in agreement with model protein composition. The variability of cellular composition of P. halodurnas and A. luteo-violaceus is discussed with respect to the measurement of bacterial growth in natural environments. Total carbon and nitrogen per cell varied greatly (coefficient of variation, ca. 100%) depending on growth conditions. Variation in total sulfur and protein per cell was much less (coefficient of variation, less than 50%), but the least variation was found for sulfate incorporation into residue protein (coefficient of variation, ca. 15%). Thus, sulfate incorporation into residue protein can be used as an accurate measurement of de novo protein synthesis in these bacteria. (Refs. 26).
Abstract in portuguese O objetivo deste trabalho foi avaliar o tempo de atuação de Lactobacillus plantarum, na microbiota bacteriana intestinal de Litopenaeus vannamei, e sua relação com a contagem total de hemócitos e a atividade da fenoloxidase após a exposição a Vibrio harveyi. Os camarões foram alimentados com dieta suplementada com probióticos por oito dias e, depois, substituída por dieta comercial. Os camarões alimentados com dieta comercial constituíram o controle. As avali (more) ações foram realizadas no oitavo dia de experimento e repetidas dois, quatro, seis e oito dias depois. A contagem total de bactérias lácticas no intestino foi maior até o quarto dia de avaliação, no grupo alimentado com probióticos. A contagem de Vibrio spp. foi superior no grupo controle nos dias zero e dois. Até o quarto dia, a contagem total de hemócitos dos camarões após a inoculação de V. harveyi foi superior no grupo alimentado com probiótico em relação ao grupo controle. Não foi observada diferença na atividade da fenoloxidase. No sexto dia, após a substituição da dieta suplementada com probióticos por dieta controle, todos os parâmetros avaliados foram iguais nos dois grupos, o que indica que o tempo de atuação de L. plantarum em camarões é curto. Abstract in english The objective of this work was to assess the time-related action of probiotic Lactobacillus plantarum in the bacterial microbiota of the digestive tract of Litopenaeus vannamei, and the relation of total haemocyte count and serum phenol oxidase activity of shrimp challenged with Vibrio harveyi. Shrimps were fed with a probiotic-supplemented diet, for eight days, then shifted to a commercial diet. Shrimps fed only with the commercial diet served as control. Evaluations wer (more) e made on the 8th day of experiment and repeated two, four, six and eight days later. Total lactic bacteria in the digestive tract was higher until the 4th day of evaluation in the probiotic-supplemented group. Vibrio spp. counts were higher in the control at days zero and two. Until the 4th day of evaluation, the total haemocyte counts in shrimps after challenge with V. harveyi were higher in probiotic-supplemented group than in control group. Significant difference was not observed in phenol oxidase activity. On the 6th day after shifting from supplemented to control diet, all parameters were equal in both groups, suggesting that the time-related action of L. plantarum in shrimp is short.
Boerewors is a South African fresh sausage preserved with 450mg/kg sulphur dioxide (SO(2)). The preservative effects of rosemary (Ros; 260mg/kg) and chitosan (Chi; 10g/kg) were compared to SO(2). Eight boerewors models were formulated. Microbial, colour, lipid and sensory characteristics were evaluated. Chi and Chi in combination with other preservatives had a significant effect on reducing total bacterial, coliform and Enterobacteriaceae counts, comparable to SO(2). Chi, however, had a better effect on decreasing yeasts and mould counts than SO(2). Chi showed good colour properties comparable to SO(2). Ros showed comparable lipid stability to SO(2) but better when compared to Chi. Ros had a better effect on the sensory taste when compared to Chi, but SO(2) was still preferred. Reduced levels of 100mg/kg SO(2) showed good antimicrobial and colour effects in combination with Chi and in combination with Ros as antioxidant and improving the sensory properties. Alternative preservatives can be used to reduce the SO(2) content of boerewors. PMID:22326060
Evaluation of a soil slurry reactor system for treating soil contaminated with munitions compounds
Two 0.5-L semicontinuous soil slurry reactors were operated for seven months to evaluate the performance of the slurry reactor system in bioremediating soil contaminated with munitions compounds. Nitrogen and carbon were supplemented. The soil slurry was mixed continuously and aerated 10 min/day. Ten percent of the contaminated soil was replaced every week. The 2,4,6-trinitrotoluene (TNT) concentration in soil began to drop after 15 days of treatment, falling to less than 0.5 mg/kg from 7800 mg/kg. Total plate counts in both reactors indicated that the bacterial population was maintained, with an average plate count of about 10{sup 8} CFU/mL. The soil slurry was slightly acidic. In addition to TNT, the slurry reactor also removed the other munitions compounds trinitrobenzene (TNB), 2,4-dinitrotoluene (2,4-DNT), RDX, and HMX. Radiolabeling studies on the reactor biomass showed that 23% of [{sup C}14]TNT was mineralized, while 27% was used as biomass and 8% was adsorbed on to the soil. The rest of the [{sup 14}C]TNT was accounted for as TNT metabolites. Increasing the frequency of soil replacement from once to two or three times weekly did not affect the TNT removal rates. However, the slurry system showed signs of stress, with highly acidic conditions and low oxygen uptake rates.
A field trial for an ex-situ bioremediation of a drilling mud-polluted site.
The remediation of drilling mud-polluted sites in the Southeast of Mexico is a top priority for Mexican oil industry. The objective of this work was to find a technology to remediate these sites. A field trial was performed by composting in biopiles, where four 1ton soil-biopiles were established, one treatment in triplicate and one unamended biopile. Amended biopiles were added with nutrients to get a C/N/P ratio of 100/3/0.5 plus a bulking agent (straw) at a soil/straw ratio of 97/3. Moisture content was maintained around 30-35%. Results showed that, after 180 d, total petroleum hydrocarbon (TPH) concentrations decreased from 99300+/-23000mgTPHkg(-1) soil to 5500+/-770mgTPHkg(-1) for amended biopiles and to 22900+/-7800mgTPHkg(-1) for unamended biopile. An undisturbed soil control showed no change in TPH concentrations. Gas chromatographic analysis showed residual alkyl dibenzothiophene type compounds. Highest bacterial counts were observed during the first 30 d which correlated with highest TPH removal, whereas fungal count increased at the end of the experimentation period. Results suggested an important role of the straw, nutrient addition and water content in stimulating aerobic microbial activity and thus hydrocarbon removal. This finding opens an opportunity to remediate old polluted sites with recalcitrant and high TPH concentration. PMID:16997351
Results of a commercial real-time PCR analysis for 11 mastitis pathogens from bulk tank milk (BTM) samples from all 4,258 Danish dairy herds in November 2009 to January 2010 were compared with somatic cell count (SCC) and total bacteria count (TBC) estimates in BTM. For Streptococcus agalactiae, Streptococcus dysgalactiae, and Streptococcus uberis, a low real-time PCR cycle threshold (Ct) value (corresponding to high bacterial DNA quantity) was correlated with higher SCC and higher TBC. For Staphylococcus aureus, low Ct values were correlated only with higher SCC. For the environmental mastitis pathogens Klebsiella spp., Enterococcus spp., and Escherichia coli, low Ct values had a correlation with higher TBC. Staphylococcus spp. were found in the BTM from all herds, Strep. uberis in 95%, Staph. aureus in 91%, and Strep. dysgalactiae in 86%, whereas E. coli, Klebsiella, and Strep. agalactiae were found in 61, 13, and 7% of the herds. It is concluded that the real-time PCR used provides results that are relatedto the milk quality in the herds. Real-time PCR can be used in the same way as culture for monitoring BTM samples, and is especially useful for bacteria with low prevalence (e.g., Strep. agalactiae). © 2012 American Dairy Science Association.
The spatial distribution of bacteria in Grana-cheese during ripening.
The microbial composition and its spatial distribution of Grana Trentino, a hard Parmesan-like cheese, was determined, from vat milk to cheese. After cutting along the vertical axis of the cheese wheels, three layers were sampled diagonally across the cheese: under the cheese rind, an intermediate section and the cheese core. After two different ripening periods (9 and 18 months), the cheese samples were analysed using traditional culture dependent and culture independent methods. Milk samples were dominated by mesophilic and psychrophilic bacterial counts. Thermophilic bacteria (Lactobacillus helveticus) were found in high amounts in cooked whey and natural whey starter cultures. After 9 months of ripening, lactic acid bacteria (LAB) counts were higher than those after 18 months. Furthermore, the LAB numbers in the cheese core was lower than those under the rind or in the intermediate section. The main LAB species isolated from milk (Lactococcus lactis, Pediococcus pentosaceus, Streptococcus uberis and Lactococcus garvieae) were not found in the corresponding cheeses. Some differences were observed in the species composition among the three cheese sections. Microbiota under the rind and in the intermediate section was similar and dominated by Lactobacillus paracasei and Lactobacillus rhamnosus. The core, after 18 months of ripening, was characterized by a total absence of LAB. In each sample, all LAB were genotypically grouped and the different biotypes were subjected to several technological tests indicating that some non-starter LAB (NSLAB) displayed technological features that are favorable for the production of Grana Trentino cheese. PMID:21943677
The Deepwater Horizon Oil Spill was the largest oil spill in USA history releasing approximately 4.9 million barrels of crude oil into the Gulf of Mexico. Soon after the spill started, tar balls and other forms of weathered oil appeared in large numbers on beaches in Mississippi and Alabama. In this study, we analyzed tar balls for total aerobic bacterial (TAB) counts and also for the presence of Vibrio vulnificus, a human pathogen known to be abundant in the Gulf Coast environment and capable of causing severe wound infections by contact with contaminated surfaces. Our results showed that TAB counts were significantly higher in tar balls than in sand and seawater collected at the same location. In addition, V. vulnificus numbers were 10× higher in tar balls than in sand and up to 100× higher than in seawater. Densities of V. vulnificus were higher than 10(5) colony forming units/g of tar ball in all samples analyzed. Our data suggest that tar balls can act as reservoirs for bacteria including human pathogens. PMID:22109669
The paper presents the methodology followed in order to define the relationship between the removal of inorganic and/or viable particulates and a commercial electrostatic precipitator, FEMEC like configured. Inorganic aerosols needed to control the efficiency removal were generated through an ultrasonic home humidifier, while a bacterial characterised air flow was obtained directly from the duet work of the central heating and cooling system serving the environmental analyses laboratory of the University of Ancona. Microbiological analyses were performed by a traditional plate count method. The difference between the amount of viable bacteria evaluated on plate count data, in the presence of electrostatic filtration, results statistically significative. Bacterial removal by electrostatic filtration resulted on an average of 79% of the samples analysed. [Italian] Il presente lavoro riassume la metodologia seguita per la definizione del rapporto esistente fra il funzionamento di un filtro elettrostatico commerciale a piastre doppio stadio tipo FEMEC e l'abbattimento sia di particolato inorganico sia di particolato di tipo biologico vivo, provenienti da impianti di termoventilazione. La generazione di particolato inorganico e' stata realizzata tramite generatore ultrasonico alimentato con soluzione salina di solfato di ammonio. La carica batterica in ingresso al filtro e' stata ottenuta direttamente dall'impianto di climatizzazione di tipo misto al servizio del laboratorio chimico ambientale dell'Universita' di Ancona. Nelle condizioni operative impiegate e' stata verificata una differenza statisticamente significativa dell'abbattimento della carica batterica totale ottenuta tramite filtrazione elettrostatica dell'aria. Il risultato dei conteggi nei campioni di aria filtrati evidenzia un conteggio nullo nel 79%, contro un 37% nei prelievi eseguiti in assenza di filtrazione.
Irradiation treatment of minimally processed carrots for ensuring microbiological safety
Minimally processed fruits and vegetables are very common in developed countries and are gaining popularity in developing countries due to their convenience and freshness. However, minimally processing may result in undesirable changes in colour, taste and appearance due to the transfer of microbes from skin to the flesh. Irradiation is a well-known technology for elimination of microbial contamination. Food irradiation has been approved by 50 countries and is being applied commercially in USA. The purpose of this study was to evaluate the effect of irradiation on the quality of minimally processed carrots. Fresh carrots were peeled, sliced and PE packaged. The samples were irradiated (0, 0.5, 1.0, 2.0, 2.5, 3.0 kGy) and stored at 5 deg. C for 2 weeks. The samples were analyzed for hardness, organoleptic acceptance and microbial load at 0, 7th and 15th day. The mean firmness of the control and all irradiated samples remained between 4.31 and 4.42 kg of force, showing no adverse effect of radiation dose. The effect of storage (2 weeks) was significant (P< 0.05) with values ranging between 4.28 and 4.39 kg of force. The total bacterial counts at 5 deg. C for non-irradiated and 0.5 kGy irradiated samples were 6.3x10{sup 5} cfu/g, 3.0x10{sup 2} and few colonies(>10) in all other irradiated samples(1.0, 2.0, 2.5 and 3.0 kGy) after 2 weeks storage. No coliform or E. coli were detected in any of the samples (radiated or control) immediately after irradiation and during the entire storage period in minimally processed carrots. A dose of 2.0 kGy completely controlled the fungal and bacterial counts. The irradiated samples (2.0 kGy) were also acceptable sensorially.
For the first time, we report the fabrication of a titanium bacterial chip for MALDI-MS produced from a simple, cost effective and rapid heat treatment process. This bacterial chip can be reused many times and is highly versatile. These bacterial chips serve dual roles: (1) They can be applied as MALDI-MS target plates for direct and highly sensitive bacterial analysis. (2) They can be used as bacterial sensors for direct analysis of the captured bacteria using MALDI-MS. The sensitivity of these chips when used as bacterial sensors is <103cfu/mL. The lowest detectable concentration for direct MALDI-MS analysis was found to be 104cfu/mL. The results were further justified by using standard plate counting method combined with Tukey–Kramer statistical analysis and fluorescence...
For the first time, we report the fabrication of a titanium bacterial chip for MALDI-MS produced from a simple, cost effective and rapid heat treatment process. This bacterial chip can be reused many times and is highly versatile. These bacterial chips serve dual roles: (1) They can be applied as MALDI-MS target plates for direct and highly sensitive bacterial analysis. (2) They can be used as bacterial sensors for direct analysis of the captured bacteria using MALDI-MS. The sensitivity of these chips when used as bacterial sensors is <10(3)cfu/mL. The lowest detectable concentration for direct MALDI-MS analysis was found to be 10(4)cfu/mL. The results were further justified by using standard plate counting method combined with Tukey-Kramer statistical analysis and fluorescence imaging followed by image processing for fluorescence quantification using ImageJ software to substantiate the MALDI-MS results. PMID:22835524
Molecular analysis of gut microbiota in obesity among Indian individuals.
Obesity is a consequence of a complex interplay between the host genome and the prevalent obesogenic factors among the modern communities. The role of gut microbiota in the pathogenesis of the disorder was recently discovered; however, 16S-rRNA-based surveys revealed compelling but community-specific data. Considering this, despite unique diets, dietary habits and an uprising trend in obesity, the Indian counterparts are poorly studied. Here, we report a comparative analysis and quantification of dominant gut microbiota of lean, normal, obese and surgically treated obese individuals of Indian origin. Representative gut microbial diversity was assessed by sequencing fecal 16S rRNA libraries for each group (n=5) with a total of over 3000 sequences. We detected no evident trend in the distribution of the predominant bacterial phyla, Bacteroidetes and Firmicutes. At the genus level, the bacteria of genus Bacteroides were prominent among the obese individuals, which was further confirmed by qPCR (P less than 0.05). In addition, a remarkably high archaeal density with elevated fecal SCFA levels was also noted in the obese group. On the contrary, the treated-obese individuals exhibited comparatively reduced Bacteroides and archaeal counts along with reduced fecal SCFAs. In conclusion, the study successfully identified a representative microbial diversity in the Indian subjects and demonstrated the prominence of certain bacterial groups in obese individuals; nevertheless, further studies are essential to understand their role in obesity. PMID:22922190
Contribution of reactive oxygen species to UV-B-induced damage in bacteria.
The present work aimed to identify the reactive oxygen species (ROS) produced during UV-B exposure and their biochemical targets, in a set of bacterial isolates displaying different UV susceptibilities. For that, specific exogenous ROS scavengers (catalase/CAT, superoxide dismutase/SOD, sodium azide and mannitol) were used. Biological effects were assessed from total bacterial number, colony counts and heterotrophic activity (glucose uptake and respiration). DNA strand breakage, ROS generation, oxidative damage to proteins and lipids were used as markers of oxidative stress. Sodium azide conferred a statistically significant protection in terms of lipid oxidation and cell survival, suggesting that singlet oxygen might play an important role in UV-B induced cell inactivation. Mannitol exerted a significant protection against DNA strand breakage and protein carbonylation, assigning hydroxyl radicals to DNA and protein damage. The addition of exogenous CAT and SOD significantly protected the capacity for glucose uptake and respiration, suggesting that superoxide and H(2)O(2) are involved in the impairment of activity during UV-B exposure. The observation that amendment with ROS scavengers can sometimes also exert a pro-oxidant effect suggests that the intracellular oxidant status of the cell ultimately determines the efficiency of antioxidant defenses. PMID:23026387
Abstract in english Antibiotic-resistant coliform bacteria from raw and treated water from activated sludge of a sewage treatment plant were isolated on eosin methylene blue agar (EMB) plates in the separate presence of ampicillin, tetracycline, chloramphenicol and streptomycin. Antibiotic resistant coliforms obtained from inflow and effluent waters were studied to determine influences of treatment on the species composition, resistance patterns and transferable resistance in these bacteria. (more) The bacterial counts obtained showed a high proportion of antibiotic resistant coliforms in the treated effluent. The resistant coliform species were eliminated at different rates by the treatment. Escherichia coli decreased, whereas the proportion of Klebsiella sp increased. The percentage of multiple-resistant isolates increased at the end of the treatment process. The high frequency of resistance was to ampicillin, followed by tetracycline and sulpha-trimethoprim. Moderate incidence of resistance was to streptomycin, chloramphenicol and cephradine. The lowest rate of resistance was to kanamicin and nalidixic acid. Mating experiments of multiple-resistant coliforms with an E. coli K-12 donor confirmed the capability of transferring its resistance. The results of this study suggested that wastewater treatment could reduce the total number of enteric bacteria in sewage, but may increase the proportion of antibiotic resistant coliforms in effluent water. Environmental release and agricultural use of treated sewage effluent containing bacteria having elevated antibiotic resistance levels presents a potential public health risk, as well as the risk of transferring the antibiotic resistance to bacterial populations in the environment.
Evaluation of electron beam irradiation for disinfection of turmeric fingers
Turmeric finger as one of the most popular spices has been widely used for food manufacturing. However, it has also been a major cause of bacterial infestation of food materials especially in curry, ham and sausage manufacturing. In this study decontamination of bacteria in turmeric finger by electron beam irradiation was evaluated by comparing with several other decontamination methods: i.e., boiling, microwave irradiation, treatment by twin screw extruder and gamma-ray irradiation. By estimation of colony counting on nutrient agar plate, turmeric finger without any treatment gave total viable cell at 10{sup 8}/g. Turmeric finger which was irradiated by electron beam at 10 kGy dose dramatically reduced thermotolerant cell population below self restriction level (<1000/g), which has been required by food hygiene law. The same level of sterilization effect was obtained only by gamma-ray irradiation at 10 kGy and 20 kGy. On the other hand, although treatment through twin screw extruder slightly reduced bacterial numbers, neither boiling nor microwave irradiation gave sufficient decontamination effect on turmeric fingers. (author).
Membranes with antibacterial properties were developed using surface modification of polyethersulfone ultrafiltration membranes. Three different modification strategies using polyelectrolyte layer-by-layer (LbL) technique are described. The first strategy relying on the intrinsic antibacterial properties of poly(diallyldimethylammonium chloride) (PDADMAC) and poly(ethylenimine) (PEI) exhibits only little antibacterial effects. The other two strategies contain silver in both ionic (Ag(+)) and metallic (Ag(0)) form. Ag(+) embedded into negatively charged poly(sodium 4-styrene sulfonate) (PSS) layers totally inhibits bacterial growth. Ag(0) nanoparticles were introduced to the membrane surface by LbL deposition of chitosan- and poly(methacrylic acid) - sodium salt (PMA)-capped silver nanoparticles and subsequent UV or heat treatment. Antibacterial properties of the modified membranes were quantified by a new method based on the Respiration Activity Monitoring System (RAMOS), whereby the oxygen transfer rates (OTR) of E. coli K12 cultures on the membranes were monitored online. As opposed to colony forming counting method RAMOS yields more quantitative and reliable data on the antibacterial effect of membrane modification. Ag-imprinted polyelectrolyte film composed of chitosan (Ag(0))/PMA(Ag(0))/chitosan(Ag(0)) was found to be the most promising among the tested membranes. Further investigation revealed that the concentration and equal distribution of silver in the membrane surface plays an important role in bacterial growth inhibition. PMID:22884245
Symbiont-mediated insecticide resistance.
Development of insecticide resistance has been a serious concern worldwide, whose mechanisms have been attributed to evolutionary changes in pest insect genomes such as alteration of drug target sites, up-regulation of degrading enzymes, and enhancement of drug excretion. Here, we report a previously unknown mechanism of insecticide resistance: Infection with an insecticide-degrading bacterial symbiont immediately establishes insecticide resistance in pest insects. The bean bug Riptortus pedestris and allied stinkbugs harbor mutualistic gut symbiotic bacteria of the genus Burkholderia, which are acquired by nymphal insects from environmental soil every generation. In agricultural fields, fenitrothion-degrading Burkolderia strains are present at very low densities. We demonstrated that the fenitrothion-degrading Burkholderia strains establish a specific and beneficial symbiosis with the stinkbugs and confer a resistance of the host insects against fenitrothion. Experimental applications of fenitrothion to field soils drastically enriched fenitrothion-degrading bacteria from undetectable levels to >80% of total culturable bacterial counts in the field soils, and >90% of stinkbugs reared with the enriched soil established symbiosis with fenitrothion-degrading Burkholderia. In a Japanese island where fenitrothion has been constantly applied to sugarcane fields, we identified a stinkbug population wherein the insects live on sugarcane and ?8% of them host fenitrothion-degrading Burkholderia. Our finding suggests the possibility that the symbiont-mediated insecticide resistance may develop even in the absence of pest insects, quickly establish within a single insect generation, and potentially move around horizontally between different pest insects and other organisms. PMID:22529384
Development of insecticide resistance has been a serious concern worldwide, whose mechanisms have been attributed to evolutionary changes in pest insect genomes such as alteration of drug target sites, up-regulation of degrading enzymes, and enhancement of drug excretion. Here, we report a previously unknown mechanism of insecticide resistance: Infection with an insecticide-degrading bacterial symbiont immediately establishes insecticide resistance in pest insects. The bean bug Riptortus pedestris and allied stinkbugs harbor mutualistic gut symbiotic bacteria of the genus Burkholderia, which are acquired by nymphal insects from environmental soil every generation. In agricultural fields, fenitrothion-degrading Burkolderia strains are present at very low densities. We demonstrated that the fenitrothion-degrading Burkholderia strains establish a specific and beneficial symbiosis with the stinkbugs and confer a resistance of the host insects against fenitrothion. Experimental applications of fenitrothion to field soils drastically enriched fenitrothion-degrading bacteria from undetectable levels to >80% of total culturable bacterial counts in the field soils, and >90% of stinkbugs reared with the enriched soil established symbiosis with fenitrothion-degrading Burkholderia. In a Japanese island where fenitrothion has been constantly applied to sugarcane fields, we identified a stinkbug population wherein the insects live on sugarcane and ?8% of them host fenitrothion-degrading Burkholderia. Our finding suggests the possibility that the symbiont-mediated insecticide resistance may develop even in the absence of pest insects, quickly establish within a single insect generation, and potentially move around horizontally between different pest insects and other organisms. PMID:17822128
Somatic Cells Count in Cow’s Bulk Tank Milk
The objective of this study was therefore to present factors affecting somatic cell counts in bovine bulk milk as a result of intramammary infections as well as non-infectious factors. The paper presents also the impact of on-farm management practices on the level of bulk milk somatic cell counts and presents quality indicators in bulk tank milk. At the farm level bulk milk bacterial infection takes place through three main sources: bacterial contamination from the external surface of the udder and teats, from the surface of the milking equipment, and from mastitis microorganisms within the udder. The threshold of 200,000 cells/ml identifies bacteriological negative quarters of the udder. The counts of mammary pathogens in bulk tank milk are relatively low, on average not exceeding 1,000 cfu/ml. Environmental pathogens predominate in bulk tank milk samples with somatic cells count 3/ml.
Somatic Cells Count in Cow's Bulk Tank Milk
The objective of this study was therefore to present factors affecting somatic cell counts in bovine bulk milk as a result of intramammary infections as well as non-infectious factors. The paper presents also the impact of on-farm management practices on the level of bulk milk somatic cell counts and presents quality indicators in bulk tank milk. At the farm level bulk milk bacterial infection takes place through three main sources: bacterial contamination from the external surface of the udder and teats, from the surface of the milking equipment, and from mastitis microorganisms within the udder. The threshold of 200,000 cells/ml identifies bacteriological negative quarters of the udder. The counts of mammary pathogens in bulk tank milk are relatively low, on average not exceeding 1,000 cfu/ml. Environmental pathogens predominate in bulk tank milk samples with somatic cells count < 300 × 103/ml.
Luminescent bacteria-based sensing method for methylmercury specific determination
A bacterial biosensor method for the selective determination of a bioavailable organomercurial compound, methylmercury, is presented. A recombinant luminescent whole-cell bacterial strain responding to total mercury content in samples was used. The bacterial cells were freeze-dried and used as robust, reagent-like compounds, without batch-to-batch variations. In this bacteria-based sensing method, luciferase is used as a reporter, which requires no substrate additions, therefore allowing homogenous, real-time monitoring of the reporter gene expression. A noninducible, constitutively light-producing control bacterial strain was included in parallel for determining the overall cytotoxicity of the samples. The specificity of the total mercury sensor Escherichia coli MC1061 (pmerRBlux) bacteri...
In this study, microbiological aspects of Grana Trentino, a variant of Grana Padano cheese, were defined by plate counts, random amplified polymorphic DNA (RAPD) PCR genotying, 16S rRNA gene sequencing of bacterial isolates and PCR-denaturing gradient gel electrophoresis (PCR-DGGE). Results showed variability in monthly fluctuations of whey culture counts, differences in the diffusion of bacterial genotypes among producers and dairy plant-specific microbial associations. Moreover, the presence of bacteria not previously reported in this cheese type was highlighted, including coagulase-negative staphylococci and Lactobacillus sanfranciscensis-like micro-organisms.
Application of ATP bioluminescence for evaluation of surface cleanliness of milking equipment
The ATP bioluminescence method was used to evaluate the cleanliness of milking equipment surfaces (teat cup rubbers, teat dip containers, milk receivers, and pipeline joints) in dairy farms in Galicia (northwest Spain) with parlour, pipeline tie-stall or bucket tie-stall milking systems. The cleanest surfaces were teat cup rubbers. The use of non-chlorinated water for cleaning, and of pipeline or bucket tie-stall milking systems, was associated with high ATP bioluminescence values. However, ATP bioluminescence values only explained 12% of the variability in bulk-tank bacterial count; this is attributable to the importance of other factors (notably the correct functioning of the tank cooling system) for maintenance of low bacterial count.
Background: The hygienic-microbiological control of 6 dental units being in use for the past 16 years revealed a significantly increased microbial contamination of their cooling water system. In order to comply with the requirements of the drinking water directive ("Trinkwasserverordnung"), the commercially available production system ActiDes, producing on-site ActiDes-Blue which is based on hypochlorous acid (HOCl) and generated by anodic oxidation, was investigated. Method: Water samples from the 6 contaminated dental units were examined for the total number of colony forming units (cfu), contamination with molds, L. pneumophila and P. aeruginosa. The control period for the total colony count was 4 weeks (8 samples/unit). The subsequent application phase of the ActiDes-Blue procedure was 6 months (31 samples/unit). Additionally, the redox potential and the pH value were measured.Futhermore, the decontamination agent CARELA HYDRO-DES, a two component agent based on H(2)O(2) with the addition of a mixture of sodium hydrogen sulphate and sulphuric acid in an aqueous solution effective at 0.1% and higher, was applied in a unit that had been put out of service for a month before. Before application, the system was first filled with a 5% solution of the alkaline pre-cleaning agent CARELA Solvent for bacterial slime; the system was left with this solution for 1 h. The pre-cleaning agent was then completely displaced from the system with tap water and a decontaminating solution of 5% CARELA HYDRO-DES and left in place for 1 h.Results: Drinking water quality level was reached only twice during the control phase. The average values of the dental units ranged between 3,633 CFU/ml and 29,417 c/ml. During the application phase, drinking water level could be achieved in 11 water samples. In another 6 water samples a total colony count of dental units' total colony count ranged between 529 cfu/ml and 87,450 cfu/ml. No significant differences between the control phase and the action phase could be demonstrated. During the control phase, contamination of the water samples with a mold was noticed so that examinations for molds were carried out beyond the scope of the drinking water directive. For this parameter as well, no significant differences between the phases of the study could be shown.The Legionella load of the dental units was low. L. pneumophila were yielded in only 4 out of 130 water samples. During the control phase, twice colony counts at 50 cfu/1,000 ml and 110 cfu/1,000 ml were measured. During the action phase, counts with Legionella spp. could be measured at 5 cfu/1,000 ml for one unit only. Also, with 1-10 cfu/100 ml, the P. aeruginosa contamination was low. During the application phase, it ranged between 0-7 cfu/100 ml.Redox potential and pH value showed a slight decrease during the application phase.Before treatment with CARELA Solvent and CARELA HYDRO-DES, the initial contamination of the total count of bacterial colonies was 1,432 cfu/ml at 22°C and 846 cfu/ml at 36°C as well as >1,000 cfu/100 ml for molds. 1 h after the decontamination, no bacteria and molds could be detected in 1,000 ml of tap water. Despite the fact that the unit was not used any longer, after 7 d the bacterial colony count was 3 cfu/ml at 22°C and 2 cfu/ml at 36°C while molds could not be detected. Even after a rest time of 14 d only 167 cfu/ml or 42 cfu/ml could be yielded. Molds were further not cultivable. A material damage could not be observed. Discussion: Pertaining to the ActiDes technology's effectiveness, it has to be pointed out that the dental units investigated were those used for dental students' teaching and therefore were clearly less frequently used than clinically used units in a dental practice. This resulted in distinctly longer stagnation periods which favored formation of biofilms. Conclusions: In summary, the ActiDes technology and ActiDes-Blue showed not to be sufficiently effective for the sanitation of contaminated water reservoirs in dental units under aggravated conditions of repeated and longer periods of non-use in connection with longer water stagnation periods. In comparison, the biofilm was sustainably eliminated through the combined application of CARELA(®) Solvent for Bacterial Slime with subsequent decontamination using CARELA(®) HYDRO-DES. PMID:22558043
Abstract in spanish El objetivo de este trabajo fue la utilización de cepas bacterianas autóctonas en la biorremediación de agua contaminada con aceite lubricante. Se tomaron muestras de agua del Lago de Maracaibo, sector Capitán Chico, Edo. Zulia. Se aislaron 16 cepas bacterianas, las cuales fueron sometidas a un ensayo de factibilidad, utilizando gasoil como única fuente de carbono. Se seleccionaron e identificaron las siete cepas más eficientes en la degradación de los hidrocarburo (more) s. Se preparó un cultivo mixto con dichas cepas, el cual se utilizó en un estudio de biotratabilidad. En tanques plásticos de 25 L se dispensaron: cultivo mixto (10%), aceite lubricante (7000 mg/L), nitrógeno y fósforo (0,5; 0,75; 1 g/L), en un volumen de 20 L. En cuatro de los tratamientos, se aplicó aireación. Mensualmente, se registró el contaje bacteriano, el contenido de aceite y el contenido de nitrógeno y fósforo totales. Se aplicó un análisis de varianza con tres repeticiones, utilizando un modelo lineal estadístico. El efecto de la aplicación de cultivo mixto, fertilización y aireación sobre la degradación de aceite resultó significativo (P Abstract in english The objective of this work was the bioremediation of contaminated water with lubricant oil by using endogenous bacterial strains. Samples of water were taken from the Lake of Maracaibo, sector Capitan Chico, Edo. Zulia. From the water samples, 16 bacterial strains were isolated, which were subjected to a essay of feasibility using gasoil as carbon source. The seven bacterial strains more efficient during the essay of feasibility were identified and utilized as a mixed cul (more) ture in a biotratabilidad study. The essay were prepared in plastic tanks of 25 L with mixed culture (10%), oil lubricant (7000 mg/L), nitrogen and phosphorus (0,5; 0,75; 1 g/L), in a total volume of 20 L. In four of the treatments aeration was applied. Monthly the bacterial count, the oil content, the nitrogen and total phosphorus content were registered. In the inoculated, fertilized and aired tanks the highest removals were achieved, until 95% of the oil was present.
Three years of regular weekly/biweekly monitoring of seasonal changes in temperature, transparency, chlorophyll a (CHL) and bacteria [erythrosine-stained microscopic counts and cultivable colony forming units (CFUs)] at the vertical profile in the South basin of Lake Baikal (51°54?195?N, 105°04?235?E, depth 800 m) were evaluated. In more detail, the structure and function of phytoplankton and the microbial loop in the euphotic layer at the same site were investigated during the late-winter early-spring period under the ice. The depth of euphotic zone (up to 1% of surface irradiation) was 35 to 40 m. Primary production was measured three times a week with the 14C method in 2, 10, 20, 30 and 40 m. Maximum production was found in 10 m, with lower values towards the surface (light inhibition) and towards the lower layers. The total production in cells larger than 1 ?m in the column (0 40 m) was 204 240 mg C d-1 m-2, 30 40% of it being in cells 1 3 ?m (mostly picocyanobacteria), which represented roughly 9% of the total chlorophyll a (estimated from pigment analyses). A major part of phytoplankton biomass was formed by diatoms (Synedra acus Hust., Asterionella formosa Hass. and Stephanodiscus meyerii Genkal & Popovskaya). Total production (including extracellular, dissolved organic matter) was 235 387 mg C day-1 m-2, and the exudates were readily used by bacteria (particles 0.2 1 ?m). This part amounted to 1 5% of cellular production in 2 to 20 m and 11 77% of cellular production in 20 40 m, i.e., in light-limited layers. From 0 to 30 m, chlorophyll a concentration was 0.8 to 1.3 ?g l-1, wherefrom it decreased rapidly to 0.1 ?g l-1 towards the depth of 40 m. Bacteria (DAPI-stained microscopic counts) reached 0.5 1.4×106 ml-1; their cell volumes measured via image analysis were small (average 0.05 ?m-3), often not well countable when erythrosine stain was used. Bacterial biomasses were in the range of 6 21 ?g C l-1. Numbers of colony forming units (CFUs) on nutrient fish-agar were c. 3 4 orders lower than DAPI counts. The amounts of heterotrophic protists were low, whereby flagellates reached 6 to 87 ml-1 and ciliates, 0.2 1.2 ml-1 (mostly Oligotrichida). Bacterial production was measured in the same depths as primary production using 3H-thymidine (Thy) and 14C-leucine (Leu) uptake. Consistently, bacterial abundances, biomasses, thymidine and leucine production were higher by 30 50% in layers 2, 10 and 20 m compared with that in the deeper 30 and 40 m, where cellular primary production was negligible. Leucine uptake in the deeper layers was even three times lower than in the upper ones. From the comparison of primary and bacterial production, bacteria roughly use 20 40% of primary production during 24 h in the layers 2 to 20 m.
Ants significantly change the soil environment within the nest. The aim of this study is to contribute to ecology and thus the importance of two ant species Lasius niger and Lasius flavus in a post-mining landscape near the town of Sokolov in northwest Bohemia where both species are common. Chemical (total C, N, and available P) and microbiological parameters (respiration, cellulose decomposition and direct counts of bacteria) were investigated in both ant species in two different habitats: a tertiary clay heap after brown coal mining with a weakly developed organic layer and semi natural meadows with well developed organic horizons. Total C and N in the L. flavus mound was lower than in the surrounding soil in both stands, the same was true for total N in L. niger on the heaps. L. niger nests in both sites were significantly enriched by available P. A litter bag test with cellulose indicated lower decomposition in the ant nest in comparison with the surrounding soil. Respiration seems to be limited by lower soil moisture in the nest. However, microbial respiration, even in suitable moisture conditions, did not differ between the nest and soil (on heaps) or nest respiration was significantly lower (in L. flavus nests in the meadow). In meadow soil both species had a lower bacteria count than the surrounding soil, but the L. niger nest on the heap had higher bacterial numbers. Both species significantly alter soil conditions, although the effect on selected parameters is variable. Moreover, the result with lower nest moisture and lower decomposition rate in ant mounds indicates that soil moisture should be the next important factor limiting soil processes inside ant mounds.
Abstract in english Earthworms are soil invertebrates that play a key role in recycling organic matter in soils.In Nigeria, earthworms include Libyodrillus violaceous. Aerobic and anaerobic bacterial counts, as well as fungal counts of viable microorganisms in soils and gut sections, were made on twenty L. violaceous collected from different sites on the campus of the University of Agriculture, Abeokuta, Nigeria. The samples were collected between April and November, 2002. Numbers of microor (more) ganisms were higher in castings and gut sections than in uningested soil samples. The guts and their contents also had higher moisture and total nitrogen contents than the uningested soils. Bacteria and fungi isolated from the samples were identified by standard microbiological procedures on the bases of their morphological and biochemical characteristics. Isolated bacteria were identified as Staphylococcus, Bacillus spp., Pseudomonas aeruginosa, Streptococcus mutans, Clostridium, Spirocheata spp., Azotobacter spp., Micrococcus lylae, Acinetobacter spp., Halobacterium for bacteria. Yeast isolates were identified as Candida spp., Zygosaccharomyces spp., Pichia spp., and Saccharomyces spp while molds were identified as, Aspergillus spp., Pytium spp., Penicillium spp., Fusarium spp and Rhizopus spp. Of the five locations examined, the refuse dump area had the highest numbers of both aerobic and anaerobic organisms, followed by the arboretum while the cultivated land area recorded the lowest counts. The higher numbers of microorganisms observed in the gut sections and casts of the earthworms examined in this work reinforce the general concept that the gut and casts of earthworms show higher microbial diversity and activity than the surrounding soil. Rev. Biol. Trop. 54 (1): 49-58. Epub 2006 Mar 31.
Extended-spectrum beta-lactamases (ESBLs), mainly of the CTX-M family, have been associated with Escherichia coli strains of animal origin in Europe. An in vivo experiment was performed to study the effects of veterinary beta-lactam drugs on the selection and persistence of ESBL-producing E. coli in the intestinal flora of pigs. Twenty pigs were randomly allocated into three treatment groups and one control group. All pigs were inoculated intragastrically with 10(10) CFU of a nalidixic acid (NAL)-resistant mutant derived from a CTX-M-1-producing E. coli strain of pig origin. Treatment with amoxicillin, ceftiofur, or cefquinome according to the instructions on the product label was initiated immediately after bacterial inoculation. Feces were collected from the rectum before inoculation and on days 4, 8, 15, 22, and 25 after the start of treatment. The total and resistant coliforms were counted on MacConkey agar with and without cefotaxime (CTX). Furthermore, MacConkey agar with CTX and NAL was used to count the number of CFU of the inoculated strain. Significantly higher counts of CTX-resistant coliforms were observed in the three treatment groups than in the control group for up to 22 days after the discontinuation of treatment. Ceftiofur and cefquinome exerted larger selective effects than amoxicillin, and the effects persisted beyond the withdrawal times recommended for these cephalosporins. The inoculated strain was detected in only nine animals on day 25. The increase in the number of CTX-resistant coliforms was mainly due to the proliferation of indigenous CTX-M-producing strains and the possible emergence of strains that acquired CTX-M genes by horizontal transfer. The study provides evidence that the cephalosporins used in pig production select for CTX-M-producing E. coli strains. Their use in animals should be carefully considered in view of the critical importance of cephalosporins and the zoonotic potential of ESBL-producing bacteria.
Sulfidogenesis in low pH (3.8-4.2) media by a mixed population of acidophilic bacteria.
A defined mixed bacterial culture was established which catalyzed dissimilatory sulfate reduction, using glycerol as electron donor, at pH 3.8-4.2. The bacterial consortium comprised a endospore-forming sulfate reducing bacterium (isolate M1) that had been isolated from acidic sediment in a geothermal area of Montserrat (West Indies) and which had 94% sequence identity (of its 16S rRNA gene) to the Gram-positive neutrophile Desulfosporosinus orientis, and a Gram-negative (non sulfate-reducing) acidophile (isolate PFBC) that shared 99% gene identity with Acidocella aromatica. Whilst M1 was an obligate anaerobe, isolate PFBC, as other Acidocella spp., only grew in pure culture in aerobic media. Analysis of microbial communities, using a combination of total bacterial counts and fluorescent in situ hybridization, confirmed that concurrent growth of both bacteria occurred during sulfidogenesis under strictly anoxic conditions in a pH-controlled fermenter. In pure culture, M1 oxidized glycerol incompletely, producing stoichiometric amounts of acetic acid. In mixed culture with PFBC, however, acetic acid was present only in small concentrations and its occurrence was transient. Since M1 did not oxidize acetic acid, it was inferred that this metabolite was catabolized by Acidocella PFBC which, unlike glycerol, was shown to support the growth of this acidophile under aerobic conditions. In fermenter cultures maintained at pH 3.8-4.2, sulfidogenesis resulted in the removal of soluble zinc (as solid phase ZnS) whilst ferrous iron remained in solution. Potential syntrophic interactions, involving hydrogen transfer between M1 and PFBC, are discussed, as is the potential of sulfidogenesis in acidic liquors for the selective recovery of heavy metals from wastewaters. PMID:16456614
Agricultural biogas plants were operated in most cases below their optimal performance. An increase in the fermentation temperature and a spatial separation of hydrolysis/acetogenesis and methanogenesis are known strategies in improving and stabilizing biogas production. In this study, the dynamic variability of the bacterial and archaeal community was monitored within a two-phase leach bed biogas reactor supplied with rye silage and straw during a stepwise temperature increase from 55 to 75 °C within the leach bed reactor (LBR), using TRFLP analyses. To identify the terminal restriction fragments that were obtained, bacterial and archaeal 16S rRNA gene libraries were constructed. Above 65 °C, the bacterial community structure changed from being Clostridiales-dominated toward being dominated by members of the Bacteroidales, Clostridiales, and Thermotogales orders. Simultaneously, several changes occurred, including a decrease in the total cell count, degradation rate, and biogas yield along with alterations in the intermediate production. A bioaugmentation with compost at 70 °C led to slight improvements in the reactor performance; these did not persist at 75 °C. However, the archaeal community within the downstream anaerobic filter reactor (AF), operated constantly at 55 °C, altered by the temperature increase in the LBR. At an LBR temperature of 55 °C, members of the Methanobacteriales order were prevalent in the AF, whereas at higher LBR temperatures Methanosarcinales prevailed. Altogether, the best performance of this two-phase reactor was achieved at an LBR temperature of below 65 °C, which indicates that this temperature range has a favorable effect on the microbial community responsible for the production of biogas. PMID:22899497
This study was carried out to evaluate the microbiological accumulation capability of the demosponge Spongia officinalis var. adriatica. Six microbiological parameters were researched in two sampling periods in the water and in reared sponge samples coming from sites with different degrees of microbial contamination: an off-shore fish farm displaced off the Apulian coast (Southern Adriatic Sea) and a no-impacted area displaced into the Marine Protected Area of Porto Cesareo (Apulian coast-Ionian Sea). We detected the density of culturable heterotrophic bacteria by spread plate on marine agar, total culturable bacteria at 37 degrees C on Plate Count Agar and vibrios on thiosulphate-citrate-bile-sucrose-salt (TCBS) agar. Total and fecal coliforms as well as fecal streptococci concentrations were detected by the MPN method. Bacterial densities were always higher in the sponge homogenates compared with the corresponding seawater in the sampling points and in both sampling periods. As regard vibrios, total culturable bacteria at 37 degrees C and fecal streptococci concentrations, the highest values were observed in the sponge samples coming from the off-shore fish farm during the summer period. The ability of Spongia officinalis var. adriatica to accumulate the microbial pollution indicators suggests that this species can be employed as a bioindicator for monitoring water quality. PMID:18325562
Vibrio parahaemolyticus is a natural microflora of marine and coastal water bodies and associated with mortality of larval shrimp in penaeid shrimp in ponds. Bacteriophages occur virtually in all places where their hosts exist. In this study, total distribution of V. parahaemolyticus and its phages were examined in shrimp ponds, seawater, estuary, animal surface, and tissues. Total vibrio count in sediments of two ponds was found to be 2.6 × 10(3) and 5.6 × 10(3) cfu/g. Incidence of V. parahaemolyticus in the ponds was close, while it was markedly higher in the animal surface and tissue samples. Biochemically identified eight strains of V. parahaemolyticus (V1, V3-V6, V9, V11, and V12) were taken for further infection studies with bacteriophage. Totally five bacteriophages capable of infecting V. parahaemolyticus MTCC-451 strain were isolated from all the samples. One of the isolated bacteriophage Vp1 from estuary was able to lyse all the isolated V. parahaemolyticus strains we used. Therefore, the morphology of Vp1 was estimated in TEM. Vp1 phage head measuring approximately about 50-60 nm diameter with icosahedral outline and a contractile tails of diameter 7 nm and length 100 nm and it was identified as Myoviridae. Therefore, the phages have the potential application in destroying bacterial pathogens. PMID:20140436
Correcting Smog Chamber Data to Obtain Organic Aerosol Yields
Aerosol size distributions are measured during smog chamber experiments to determine some physical characteristics of the aerosol such as total aerosol yield. These size distributions can be corrected by ac-counting for particle loss to the chamber walls. Greater than 30 % of the total aerosol mass yield is ac-counted for using wall loss corrections. (author)
Clorate Metabolism in Pure Cultures of E.Coli 0157:H7 Pretreated with Either Nitrate or Chlorate
Experiments were conducted to determine the effects of 5, 7.5, and 10 mM nitrate, and 5, 10, or 20 mM chlorate on total E. coli counts, chlorate metabolism, and volatile fatty acid (VFA) concentrations in anaerobic ruminal fluid cultures. Nitrate did not affect total E. coli counts (P = 0.05), chlor...
Microbial aerosols and actinomycetes in etiological considerations of mushroom workers' lungs.
Spent steamed compost, phase II compost, and dust emanating from spent compost during dumping of stationary-bed mushroom houses were examined bacteriologically. The total count for spent compost was 16 X 10(8) microorganisms per g. The total count for dust was 333 microorganisms per liter of air. Ac...
Abstract in portuguese Cem exemplares adultos de tilápia, Oreochromis niloticus, foram inoculadas intraperitonealmente com 10(8) UFC de Mycobacterium marinum e outras 100 foram mantidas sem inoculação. Inicialmente, o sangue de 6 exemplares não inoculados foi colhido e considerado como "tempo zero". Do grupo dos inoculados foi retirado sangue de 6 animais por colheita, 1, 3, 7, 14, 21, 28, 35, 42, 49, 56 e 84 dias após inoculação. Os parâmetros hematológicos: hematócrito (Hct), taxa d (more) e hemoglobina (Hgb), contagem de eritrócitos (RBC), foram determinados e os índices hematológicos (VCM, HCM e CHCM), calculados. Foram determinados também o número de trombócitos e o número total e diferencial de leucócitos. Não ocorreram alterações nos valores de Hct, Hgb, HCM e CHCM. Entretanto houve diminuição dos valores de RBC e VCM. Os valores médios de RBC e Hct dos animais no "tempo zero" foram maiores e os de VCM e HCM, menores que os dos animais inoculados. Ocorreu neutrofilia e, após 3 dias de inoculação, ocorreram linfocitose e neutropenia nos animais. No 49º. dia após inoculação bacteriana, ocorreu monocitose. Abstract in english A hundred adult of tilapia, Oreochromis niloticus, were inoculated intraperitoneally with 10(8) c.f.u. of Mycobacterium marinum. Other 100 speciemns were maintained without inoculation. Blood samples of six inoculated animals were collected at 01, 03, 07, 14, 21, 28, 35, 42, 49, 56 and 84 days after inoculation. Initially, six specimens were taken from the non inoculated group ("time zero"). The haematological parameters determined were: haematocrit (Hct), haemoglobin con (more) centration (Hgb), total erythrocytes count (RBC), hematological indexes (MCV, MCH and MCHC), thrombocyte count (Tr), leukocyte count (WBC) and leukocyte differential count. There were no changes in Hct, Hgb, MCH and MCHC. However, the mean values for RBC and MCV decreased. The mean values for RBC and Hct of specimens from the "time zero" group were higher and the MCV and MCH lower than in inoculated animals. Occurred neutrophilia, and, at 72 h there was lymphocytosis and neutropenia. By the 49th day after bacterial inoculation, there was monocytosis.
This study was conducted to evaluate (i) procedures used to collect, prepare, and count total airborne mold spore/particle concentrations, and (ii) the relative field performance of three commercially available total airborne mold spore/particle sampling devices. Differences between factory and laboratory airflow calibration values of axial fan-driven sampling instruments (used in the study) indicated a need for laboratory calibration using a mass flow meter to ensure that sample results were accurately calculated. An aniline blue-amended Calberla's solution adjusted to a pH of 4.2-4.4 provided good sample mounting/counting results using Dow Corning high vacuum grease, Dow Corning 280A adhesive, and Dow Corning 316 silicone release spray for samples collected using mini-Burkard and Allergenco samplers. Count variability among analysts was most pronounced in 5% counts of relatively low mold particle deposition density samples and trended downward with increased count percentage and particle deposition density. No significant differences were observed among means of 5, 10, and 20% counts and among analysts; a significant interaction effect was observed between analysts' counts and particle deposition densities. Significantly higher mini-Burkard and Air-O-Cell total mold spore/particle counts for 600x vs. 400x (1.9 and 2.3 x higher, respectively), 1000x vs. 600x (1.9 and 2.2 x higher, respectively) and 1000x vs. 400x (3.6 and 4.6 x higher, respectively) comparisons indicated that 1000x magnification counts best quantified total airborne mold spore/particles using light microscopy, and that lower magnification counts may result in unacceptable underreporting of airborne mold spore/particle concentrations. Modest but significantly higher (1.2x) total mold spore concentrations were observed with Allergenco vs. mini-Burkard samples collected in co-located, concurrently operated sampler studies; moderate but significantly higher mini-Burkard count values (1.4x) were observed in similar studies with Air-O-Cell samplers. These count differences were relatively small compared with the large differences observed among three count magnifications. PMID:18085480
Cultivation-independent microbial molecular ecology approaches were used to examine the effects of antibiotic growth promoters on the pig ileal microbiota. Five-week-old barrows were fitted with a simple T-cannula at the distal ileum. Three diets meeting or exceeding the minimum nutrient requirements were fed for 5 wk and supplemented as follows: 1) negative control (no antibiotic; n = 5), 2) continuous tylosin administration (n = 5), and 3) an antibiotic rotation sequence (wk 1, chlorotetracycline sulfathiazole penicillin; wk 2, bacitracin and roxarsone; wk 3, lincomycin; wk 4, carbadox; wk 5, virginiamycin; n = 5). Ileal luminal contents were collected for DNA isolation at the end of each of the 5 wk of the testing period. The V3 region of 16S rDNA was amplified by PCR and analyzed via denaturing gradient gel electrophoresis (DGGE) and quantitative polymerase chain reaction (qPCR). Resulting PCR-DGGE band numbers (bacterial species) were counted, and the banding patterns analyzed by calculating Sorenson's pairwise similarity coefficients (C(S)), an index measuring bacterial species in common among samples. Band numbers and total bacterial DNA concentrations decreased (P < 0.05) temporally in antibiotic-treated pigs compared with controls. Comparisons between treatments yielded low intertreatment C(S) indices, indicating treatment-dependent alterations in banding patterns, whereas intratreatment comparisons revealed increased homogeneity in antibiotic-treated vs. control pigs. Sequence analysis of treatment-specific bands identified three Lactobacillus, one Streptococcus, and one Bacillus species that were diminished with antibiotic rotation treatment, whereas tylosin selected for the presence of L. gasseri. Lactobacillus-specific qPCR was performed and analyzed as a percentage of total bacteria to further evaluate the effects of antibiotic administration on this genus. Total bacteria were decreased (P < 0.05) by tylosin and rotation treatments, whereas the percentage of lactobacilli increased (P < 0.05) by d 14 and through d 28 in tylosin-treated pigs. The decrease in total bacteria by antibiotics may reduce host-related intestinal or immune responses, which would divert energy that could otherwise be used for growth. Conversely, the ability of tylosin to improve animal growth may relate to its apparent selection for lactobacilli, commensals known to competitively exclude potentially pathogenic species from colonizing the intestine. PMID:14677859
Abstract in spanish El objetivo del trabajo fue validar el alto valor predictivo de BACOVA (Balance del contenido vaginal, disponible en www.fba.org.ar/proeco) en el diagnóstico microscópico diferencial de vaginosis bacteriana (VB) y vaginitis microbiana inespecífica (VMI). Fueron estudiadas 299 embarazadas sintomáticas. Se determinó por microscopía el Valor Numérico (Nugent) (VN), células guía (CG), morfotipos extraños (Mex), leucocitos por campo (Lpc), tricomonas (TV) y levaduras (more) (LE) con lectura a 400X. Los resultados globales fueron: VN de 7 a 10, 16,4% del total de casos. BACOVA permitió diferenciar 11,7% de los casos con VN de 7 a 10, con reacción inflamatoria vaginal (RIV) menor de 10 Lpc, como casos típicos de BV. Con igual VN se detectó 4,7% de casos con RIV con más de 10 Lpc, compatibles con VMI. En sólo 7,3% de los casos de LE detectadas por microscopía (20,4% en total), se confirmó una RIV significativa. Hubo 2,7% del total de casos con RIV significativa, pH Abstract in english This study was undertaken to demonstrate the high diagnostic predictive value of BACOVA (Balance of Vaginal Content, www.fba.org.ar/proeco) for bacterial vaginosis and microbial non specific vaginitis, in pregnant women primary health care. BACOVA including Nugent score (Gram 1000X) and leucocyte count (Wet mount and Giemsa, using 400X) was evaluated in 299 symptomatic pregnant women. Nugent score 7 to 10 was detected in 16.4%. Crossing Nugent value 7 to 10 with leucocyte (more) s counts shows that only 11.7% were below 10 leucocytes per field and 4.7% had a significant vaginal inflammatory response. Yeasts were detected in 20.4% but only in 7.2% of cases they show a significant association with vaginal inflammatory response. In 2.7% of the cases there was a significant vaginal inflammatory response, with pH below 4.5, VN from 0 to 3 and negative for TV, fishy odor, and exogenous microbial morphotypes. Simultaneous study of vaginal inflammatory response and Nugent score is mandatory in order to detect true cases of bacterial vaginosis (11.7%) from those of potential microbial non specific vaginitis (4.7%) (Donders' "aerobic vaginitis") Besides, vaginal inflammatory response became a strong criterion to define yeast vulvovaginitis (7.2%). Cases (2.7%) with score 0 to 3, negative for other criteria, with a high vaginal inflammatory response, are predictors of upper genital infections.
INTRODUCTION: High-mobility group box-1 protein (HMGB1) has been known as a chromosomal protein for many years. HMGB1 has recently been shown to be a proinflammatory cytokine with a role in the immunopathogenesis of sepsis. Lipopolysaccharide-binding protein (LBP) has a central role in the innate immune response when the host is challenged by bacterial pathogens. Procalcitonin (PCT) has been suggested as a marker of severe bacterial infections and sepsis. The aim of the present study was to investigate levels of HMGB1, LBP and PCT in a well-characterised sepsis cohort. The study plan included analysis of the levels of the inflammatory markers in relation to the severity of infection, to the prognosis and to the ability to identify patients with bacteraemia. METHODS: Patients suspected of having severe infections and admitted to a department of internal medicine were included in a prospective manner. Demographic data, comorbidity, routine biochemistry, microbiological data, infection focus, severity score and mortality on day 28 were recorded. Plasma and serum were sampled within 24 hours after admission. Levels of all studied markers (HMGB1, LBP, PCT, IL-6, C-reactive protein, white blood cell count and neutrophils) were measured with commercially available laboratory techniques. RESULTS: A total of 185 adult patients were included in the study; 154 patients fulfilled our definition of infection. Levels of HMGB1, LBP and PCT were higher in infected patients compared with a healthy control group (P < 0.0001). Levels of HMGB1, LBP and PCT were higher in the severe sepsis group compared with the sepsis group (P < 0.01). No differences were observed in levels of the inflammatory markers in fatal cases compared with survivors. Levels of all studied markers were higher in bacteraemic patients compared with nonbacteraemic patients (P < 0.05). PCT performed best in a receiver-operator curve analysis discriminating between bacteraemic and nonbacteraemic patients (P < 0.05). HMGB1 correlated to LBP, IL-6, C-reactive protein, white blood cell count and neutrophils (P < 0.001). LBP correlated to PCT, IL-6 and C-reactive protein (P < 0.001). CONCLUSION: Levels of HMGB1, PCT and LBP were higher in infected patients compared with those in healthy controls, and levels were higher in severe sepsis patients compared with those in sepsis patients. Levels of all studied inflammatory markers (HMGB1, LBP, PCT, IL-6) and infection markers (C-reactive protein, white blood cell count, neutrophils) were elevated among bacteraemic patients. PCT performed best as a diagnostic test marker for bacteraemia. Udgivelsesdato: 2007-null
Ecotoxicity of PSL Nanoparticles to Escherichia Coli
Ecotoxicity of PSL nanoparticles with various functional groups to Escherichia coli KP7600 strain was investigated using Colony Count method. As a result, it was found that the only positively-charged PSL nanoparticles lead to expression of the death of bacterial cells. The confocal observation of the bacterial cells after 1 h of exposure to the positively-charged PSL nanoparticles with amino acid groups dispersed in the NaCl aqueous solution showed that the surface of dead cells were almost entirely covered with the nanoparticles. In addition, the uptake of nanoparticles inside the bacterial cells was not observed regardless of the cell viability. It was supposed that the adhesion of positively-charged nanoparticles onto the surface of bacterial cells due to the electrostatic attractive force causes a decrease in the liquidity of the cell membrane, and the inhibition of metabolism through the cell membrane lead to the death of bacterial cells.
Abstract in portuguese Avaliou-se o efeito de uma dieta suplementada com Lactobacillus plantarum na engorda de Litopenaeus vannamei sobre a microbiota bacteriana do trato digestivo, a sobrevivência e alguns parâmetros hematoimunológicos após desafio com Vibrio harveyi. Não foi observada diferença significativa na sobrevivência (80±6%) e no peso final dos camarões (6,63±0,56g) durante a engorda (60 dias). A população de bactérias totais e Vibrio spp. no intestino não diferiu até o (more) 40° dia de cultivo, mas foi inferior nos camarões alimentados com dieta suplementada com probiótico no 60° dia de cultivo. A população de bactérias lácticas foi superior no intestino de camarões alimentados com dieta suplementada com probióticos após o 20° dia de cultivo. Dez horas após o desafio, a sobrevivência dos camarões alimentados com dieta suplementada com probiótico foi superior (65,7±2,9%) a dos camarões do controle (39,9±4,4%). Camarões alimentados com dieta suplementada com probióticos e desafiados com V. harveyi apresentaram menor contagem de bactérias na hemolinfa e hepatopâncreas. A contagem total de hemócitos e a atividade aglutinante da hemolinfa foram superiores nos camarões inoculados com V. harveyi alimentados com dieta suplementada com probióticos. A suplementação da dieta com probióticos modifica a microbiota bacteriana intestinal dos camarões aumentando sua resistência ao desafio com V. harveyi. Abstract in english The effect of a Lactobacillus plantarum-supplemented diet on shrimp growth, digestive tract bacterial microbiota, survival, and some hemato-immunological parameters after an experimental challenge with Vibrio harveyi was studied. No difference (P>0.05) was observed in shrimp survival (80±6%) and final weight (6.63±0.56g) after 60 days feeding trial. Total bacteria count and Vibrio spp. count in the digestive tract were not diferent (P>0.05) until day 40, but they (more) were lower (P
Microflora and Mineralization Activity in the Bottom Sediment of Lake Biwa
Microflora and mineralization activity in the bottom sediment taken from two distinct sites in Lake Biwa were investigated.From the colony formation process, the following three common features for soil bacteria were also confirmed in the sediment bacteria:1)the number of colonies increased not continuously but intermittently with incubation time;2)the number of colonies formed on diluted nutrient agar medium was considerably higher than that on nutrient agar;3)the total number of bacteria counted by epifluorescence microscopy was 100 to 10000 times higher than the number of colonies formed on both media.The following features were also found for sediment bacteria:1)the deeper the layer of the sediment, the smaller the number of colonies;2)the southern basin sediments yielded more colonies than northern basin sediments;3)the number of bacteria that can form colonies increased from spring to summer in the sediment sample contrary to the smaller count of total bacteria in the summer sample.From the bacterial activity of glucose mineralization the following points were revealed:1)the upper layer of the sediments are richer in aerobes than facultative anaerobes;and 2)under oxygen-deficient conditions even the upper layer of the sediments becomes rich in facultative anaerobes.As revealed in this study, the combination of observing the colony-forming process on agar medium and the measuring the glucose-mineralizing activity of the bacteria in the sediments seems to be useful for understanding the complex microflora in the sediments and changes relating to various factors, such as, nutrient and oxygen concentration, and temperature.
Fungi and Bacteria in or on Leaves of Eelgrass (Zostera marina L.) from Chesapeake Bay †
Samples of green and brown leaves of eelgrass (Zostera marina L.) were incubated in seawater without an additional carbon source. Parallel leaf samples were used for acridine orange bacterial counting and water-soluble aniline blue estimation of fungal biovolume. The incubations produced no evidence...
Increased survival in calves of Escherichia coli K-12 carrying an Ent plasmid.
Escherichia coli K-12 strains with and without an Ent plasmid were fed to calves, and the survival of each was monitored by viable bacterial counts of the feces. The E. coli K-12 strain carrying the Ent plasmid survived in the calves at significantly higher levels and for a longer period of time tha...
Bacteriological composition and structure of granular sludge adapted to different substrates.
The bacteriological composition and ultrastructure of mesophilic granular methanogenic sludge from a large-scale Upflow Anaerobic Sludge Blanket reactor treating wastewater from a sugar plant and of sludge granules adapted to ethanol and propionate were studied by counting different bacterial groups...
Bacterial count in prepared food or water is a key factor in assessing the quality and safety of food. It also reveals the level of hygiene adopted by food handlers in the course of preparation of such foods. This comparative study evaluated the bacteriological quality of food and water consumed in ...
The postantibiotic effect (PAE) of meropenem was determined for 11 strains, both clinical isolates and reference strains of members of the family Enterobacteriaceae. The study compares PAE results obtained by five methods used to monitor bacterial regrowth, including viable counting, alone and in co...
A single application of about 10 ml of 95% alcoholic chlorhexidine (0·5%) or tetrabrom-o-methyl phenol (0·1%) rubbed on to the hands until they were dry led to mean reduction in viable bacterial counts from standard handwashings of 97·9 ± 1·09% and 91·8 ± 4·63% respectively. After six of such treatm...
Relationship of horn fly to face fly infestation in beef cattle.
Horn fly and face fly counts (n = 394) taken on 194 beef cows representing seven breed groups were used to determine the effects of horn fly and face fly counts. Breed groups included were Angus (ANI and ANII), Chianina (CA), Charolais (CH), Hereford (HH), Polled Hereford (PH), and Red Poll (RP). The breed group designated ANI consisted of small-framed cows. Total horn fly and total face fly counts were determined weekly on each cow beginning in May and ending in late October or early November in a 3-yr (1988-90) study. Face flies were not counted on the ANI and ANII breed groups in 1988. All fly counts were taken when cows were grazing Ozark upland native grass pastures with only containment fences separating breeding groups. No insecticides were used in the study. Data for analysis were the mean annual horn fly and face fly counts (averaged across weeks), spring weight and fall weights, gain/day between spring and fall weights, and skin surface area in the spring (SSAS) and fall (SSAF) for each cow. Relationships among measurements were examined by correlation and regression procedures. Horn fly count was correlated (P < .05) with face fly count, spring weight, gain/day, and SSAS (.23, .11, -.25, and .12, respectively). Correlations of horn fly count with fall weight and SSAF were non-significant. Horn fly count, breed, and the breed x horn fly count interaction were significant (P < .05) for the face fly regression.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8002446
Bacterial Community Composition and Activity in Urban Rivers in Thailand and Malaysia
The phylogenetic composition and physiological activity of bacterioplankton communities in two different rivers in Southeast Asian countries, the Kelang River basin in Malaysia and Chao Phraya River in Thailand, which are polluted by untreated or incompletely treated sewage, were analyzed by fluorescent in situ hybridization (FISH) and FISH combined with the direct viable count technique (DVC-FISH). The results were also compared with those from temperate zone habitats in eutrophic rivers in Osaka, Japan. FISH detected 56% to 78% of total cells with the probe EUB338 targeted for the domain Bacteria in samples from the Kelang River basin, compared with 14% to 33% in samples from the Chao Phraya River. DVC-FISH with an antibiotic cocktail increased the fraction of bacteria detectable with EUB338 in the Chao Phraya River (72% to 75% of total bacteria), while no appreciable change was found in samples from the Kelang River basin. These results show that in situ physiologic activity of resident bacteria was generally high in the Kelang River basin and low but present in the Chao Phraya River. Bacterial community structures in both rivers were dominated by the beta (5% to 39%) and gamma (4% to 41%) subclasses of Proteobacteria. In river water samples from Osaka, bacterial community structures determined by FISH were dominated by the beta subclass, but those determined by DVC-FISH were dominated by both beta (26% to 39%) and gamma (17% to 47%) subclasses. This result implies that in situ physiological activity of the gamma subclass is low in the eutrophic river in Osaka, but those bacteria have the potential for cell division.
Airborne fungal succession in a rice field of Cuba
This study characterised the airborne mycobiota of a rice plantation in Bauta (Havana, Cuba), with a view to improving crop quality. Culturable airborne fungi were sampled between March 2007 and February 2008 using a volumetric method (SAS Super 100) with potato dextrose agar as culture medium. The total fungal count was 51,425?cfu/m3. The 39 filamentous genera identified included several major rice pathogens (Bipolaris, Curvularia, Alternaria, Pyricularia, Cercospora and Fusarium) as well as potentially mycotoxigenic species of Fusarium, Penicillium and Aspergillus. Analysis of the influence of weather-related factors on spore counts revealed that total counts and Penicillium counts correlated positively with daily relative humidity, mean temperature and dew point.
Seasonal variability in airborne bacterial communities at a high-elevation site
Although bacteria are ubiquitous in the near-surface atmosphere, the temporal dynamics of airborne bacterial communities have not been well-studied. We examined seasonal shifts in bacterial abundances, the relative contribution of bacteria to total aerosol loads, and bacterial community structure at a high-elevation research station in northern Colorado, USA. Aerosol samples were collected from the near-surface atmosphere over 5-10 days during each of the four calendar seasons. Bacterial abundances varied by season with the highest concentrations observed during the fall and spring seasons, consistent with the changes in total particle concentrations, with bacterial cells often representing a large fraction (22% on average) of the total near-surface aerosol particles >0.5 mm. Bacterial com...
The purpose of this examiner-blind study was threefold: to compare the microbial counts obtained by two different techniques for assessing bacterial motility, to assess the inter-rater reliability of these two techniques and to evaluate the effect of a water irrigating device (Water Pik) on bacterial motility at 3- and 6-mm probing depths. Subgingival plaque samples were taken from 10 healthy patients having at least two sites that probed greater than 6 mm, (one control, one experimental). Half of the patients were sampled at 3 mm, the other half at 6 mm, both at baseline (Day 0) and at Day 21. Two slides were prepared from each plaque sample, one for dark-field evaluation and one stained with a simplified silver-plating technique for flagella. All slides were read simultaneously by 3 observers, and the per cent motility calculated for spirochetes, motiles and all others. Strong positive inter-rater reliability correlations ranging from r = 0.95 to r = 0.99 were found for both the dark-field and flagella staining techniques. Spirochete counts obtained by both techniques were highly correlated (r = 0.91), whereas counts for motiles resulted in negative correlations between the techniques. Dark-field counts were consistently higher than the flagella stain counts for motile rods. Spirochetes were reduced, but not significantly, after irrigation of both 3-mm and 6-mm sites. Bacterial motility can be evaluated by both dark-field and flagella-staining techniques with a high degree of inter-rater reliability. PMID:2439675
Rheumatoid arthritis: regulation of synovial inflammation
Background: The hygienic-microbiological control of 6 dental units being in use for the past 16 years revealed a significantly increased microbial contamination of their cooling water system. In order to comply with the requirements of the drinking water directive (“Trinkwasserverordnung”), the commercially available production system ActiDes, producing on-site ActiDes-Blue which is based on hypochlorous acid (HOCl) and generated by anodic oxidation, was investigated. Method: Water samples from the 6 contaminated dental units were examined for the total number of colony forming units (cfu), contamination with molds, L. pneumophila and P. aeruginosa. The control period for the total colony count was 4 weeks (8 samples/unit). The subsequent application phase of the ActiDes-Blue procedure was 6 months (31 samples/unit). Additionally, the redox potential and the pH value were measured. Futhermore, the decontamination agent CARELA HYDRO-DES, a two component agent based on H2O2 with the addition of a mixture of sodium hydrogen sulphate and sulphuric acid in an aqueous solution effective at 0.1% and higher, was applied in a unit that had been put out of service for a month before. Before application, the system was first filled with a 5% solution of the alkaline pre-cleaning agent CARELA Solvent for bacterial slime; the system was left with this solution for 1 h. The pre-cleaning agent was then completely displaced from the system with tap water and a decontaminating solution of 5% CARELA HYDRO-DES and left in place for 1 h. Results: Drinking water quality level was reached only twice during the control phase. The average values of the dental units ranged between 3,633 CFU/ml and 29,417 c/ml. During the application phase, drinking water level could be achieved in 11 water samples. In another 6 water samples a total colony count of 1,000 cfu/100 ml for molds. 1 h after the decontamination, no bacteria and molds could be detected in 1,000 ml of tap water. Despite the fact that the unit was not used any longer, after 7 d the bacterial colony count was 3 cfu/ml at 22°C and 2 cfu/ml at 36°C while molds could not be detected. Even after a rest time of 14 d only 167 cfu/ml or 42 cfu/ml could be yielded. Molds were further not cultivable. A material damage could not be observed. Discussion: Pertaining to the ActiDes technology’s effectiveness, it has to be pointed out that the dental units investigated were those used for dental students' teaching and therefore were clearly less frequently used than clinically used units in a dental practice. This resulted in distinctly longer stagnation periods which favored formation of biofilms. Conclusions: In summary, the ActiDes technology and ActiDes-Blue showed not to be sufficiently effective for the sanitation of contaminated water reservoirs in dental units under aggravated conditions of repeated and longer periods of non-use in connection with longer water stagnation periods. In comparison, the biofilm was sustainably eliminated through the combined application of CARELA® Solvent for Bacterial Slime with subsequent decontamination using CARELA® HYDRO-DES. PMID:14687914
The depth distribution of sulphate-reducing bacteria (SRB) in the water column of a meromictic lake, Lake Suigetsu, Fukui, Japan was investigated using quantitative competitive PCR targeting the gene coding for portions of the ?-subunit of dissimilatory sulphite reductase (dsrA). The total bacterial cell density (DAPI count) was 5?13×106 cells mL?1 in the water column of the lake with maximum abundance occurring at the oxic-anoxic interface layer. SRB were not detected in oxic surface water using competitive PCR. SRB were found in the anoxic waters below the oxycline ranging from 104 to 105 cells mL?1, accounting for 0.3–8.9% of the total bacteria. The SRB cell densities were higher than previously estimated using the most-probable-number (MPN) method. Sequencing of the cloned PCR product of dsrA showed the existence of different SRB groups in the anoxic water. The majority of the dsrA sequences were associated with the Desulfosarcina-Desulfococcus-Desulfonema group and members of the Desulfobulbaceae family. Other dsrA clones belonged to the Desulfomicrobium and Desulfovibrio species as well as to a deeply branched group in the dsrA tree with no representatives from previously isolated SRB groups. These SRB species appear to be important for the sulphur and carbon cycle in the anoxic waters of Lake Suigetsu.
Diet supplemented with probiotic for Nile tilapia in polyculture system with marine shrimp.
The aim of this study was to assess the effect of a probiotic (Lactobacillus plantarum) supplemented diet on Nile tilapia (Oreochromis niloticus) in a polyculture system with marine shrimp (Litopenaeus vannamei) as regards culture performance, hematology, and gut bacterial microbiota. Ten 20-m² pens were arranged in one earthen pond and stocked with 2 fish (41.9 g) m(-2) and 10 shrimp (2.3 g) m(-2), in total of 40 Nile tilapias and 200 shrimp per experimental unit. Tilapia groups in five of the experimental units were fed a commercial diet supplemented with L. plantarum and the other five with an unsupplemented commercial diet (control). After 12 weeks of culture, the tilapia groups fed the probiotic-supplemented diet presented values 13.6, 7.5, and 7.1% higher for feed efficiency, yield, and final weight, respectively. Viable culturable heterotrophic bacteria counts were reduced, and the number of lactic acid bacteria was increased in the gut of fish and shrimp fed the probiotic-supplemented diet. Hematological analyses showed higher number of thrombocytes and leukocytes in tilapia fed the supplemented diet. L. plantarum utilized in this study colonized the gut of tilapia and shrimp and resulted in reduced number of total bacteria and increased tilapia final weight and feed efficiency. PMID:21347844
Comparison of the efficacy of gamma and UV irradiation in sanitization of fresh carrot juice
As there is no pasteurization procedure for the manufacture of fresh vegetable juice, both industry and consumers have sought a method for improving the storage stability and shelf-life of this category of products. In this study, the effects of commercially available, non-thermal pasteurization processes, such as gamma and UV irradiation, were compared for their efficacy in sanitizing fresh carrot juice (FCJ). FCJ was manufactured, packaged, and gamma irradiated with doses of 0, 1, 3, and 5 kGy. The manufactured FCJ was also passed through 4 UV light lamps at doses of 3.67, 4.69, and 6.50 kGy. The total aerobic bacterial count of the FCJ approached the legal limit (105 CFU/mL) after manufacturing. Both treatments were effective in reducing the number of total aerobic bacteria, and the reduced number was maintained during storage for 7 days. Gamma irradiation was more effective in suppressing microbial growth during storage. When the doses for UV treatment and gamma irradiation were higher, the inactivation effects were higher. The reduction of ascorbic acid content was greater upon gamma irradiation than UV treatment. No difference was found in the contents of flavonoids and polyphenols in FCJ after either treatment. After 3 days of refrigerated storage, the sensory scores of gamma- or UV-irradiated FCJ were superior to those of the control. The results indicate that both non-thermal treatments were effective in improving storage stability and extending shelf-life, but gamma irradiation was slightly better in suppressing microbial growth after treatment.
In present study, three strains of lactic acid bacteria (LAB) viz. Lactobacillus casei, Lactobacillus acidophilus and Lactococcus lactis and milk fermented with these strains have been studied for antioxidant and cholesterol assimilation activities in-vitro and in-vivo, in addition to the effect on total lactobacilli, lactococci and coliform counts into the gut of mice fed with diets supplemented by fermented milk. All three selected strains exhibited potent 2,2-diphenyl-1-picrylhydrazyl, malonaldialdehyde and hydrogen peroxide radical scavenging abilities as well as inhibition of linoleic acid peroxidation activity. These activities were highest in Lb. casei as followed by Lb. acidophilus and Lc. lactis. In addition, these bacterial cultures also exhibited good in-vitro cholesterol assimilation potential. Oral administration to mice of milk fermented with selected LAB strains, slightly decreased blood cholesterol, increased colonization of total lactobacilli and lactococci, and decreased coliforms in the intestinal tissues as well as faecal samples. These results indicate that, selected LAB strains have good antioxidant, hypocholesterolemic and coliform removal activities. It may suggest that, a novel functional food can be obtained by supplementation of selected LAB in milk, which may have various health beneficial properties such as antioxidant and hypocholesterolemic activities. PMID:19638266
The 16S rDNA PCR-DGGE and rpoB quantitative PCR (RQ-PCR) techniques were used to evaluate the effects of dietary flavomycin and florfenicol on the autochthonous intestinal microbiota of hybrid tilapia. The fish were fed four diets: control, dietary flavomycin, florfenicol and their combination. After 8 weeks of feeding, 6 fish from each cage were randomly chosen for the analysis. The total number of intestinal bacteria was determined by RQ-PCR. The results showed that dietary antibiotics significantly influenced the intestinal microbiota and dramatically reduced the intensity of total intestinal bacterial counts. The intensity of some phylotypes (EU563257, EU563262 and EU563255) were reduced to non-detectable levels by both dietary antibiotics, while supplementation of florfenicol to the diet also reduced the intensity of the phylotypes EU563242 and EU563262, uncultured Mycobacterium sp.-like, uncultured Cyanobacterium-like and uncultured Cyanobacterium (EU563246). Dietary flavomycin only reduced the OTU intensity of one phylotype, identified as a member of the phylum Fusobacteria. The antibiotic combination only reduced the phylotypes EU563242 and EU563262. Based on our results, we conclude that the reduced effect of florfenicol on intestinal microbiota was stronger than that of flavomycin, and when flavomycin and florfenicol were added in combination, the effect of florfenicol overshadowed that of flavomycin. PMID:20844867
BACKGROUND: Chronic rhinosinusitis (CRS) is an idiosyncratic and multifactorial disease process. Bacteria play a role in some patients, by infection or stimulation of inflammation. Staphylococcus aureus (SA) appears to be implicated in a number of infectious and inflammatory mechanisms, and may be particularly relevant in CRS patients with nasal polyps and asthma. METHODS: Middle meatus swabs from control and CRS patients collected during endoscopic sinus surgery were analyzed by quantitative polymerase chain reaction (QPCR). Total bacterial count, SA prevalence, and SA abundance were examined with respect to patient demographics and disease characteristics. RESULTS: Total bacteria, as measured by QPCR, was not statistically different between controls, CRS without nasal polyps (CRSsNP), CRS with nasal polyps (CRSwNP), or CRS with asthma groups (p nasal polyps, and asthma. CONCLUSION: The paranasal sinuses are not sterile. SA is implicated in a subset of CRS patients with nasal polyps and/or asthma. Further study is required to predict this subset of patients, and to define the mechanisms of SA pathogenesis. PMID:23055295
We describe the resident heterotrophic aerobic microflora of the salmonid posterior intestine before, during, and after the administration of rations with erythromycin in a hatchery raceway environment. We compare the profiles of medicated Chinook salmon Oncorhynchus tshawytscha with those of control fish that were not fed erythromycin. The combined counts of bacteria and yeasts per gram of fish intestine originating from four upstream raceways ranged from 3.0 ?? 102 to 9.6 ?? 105 colony-forming units (CFU) over the study period. Yeasts were commonly identified in the gut, and abundances ranged from 0% to more than 80% of the CFU. Erythromycin therapy decreased the total microbial population and altered the bacterial diversity in the gut during treatment. The intestinal microbial populations in fish medicated with erythromycin increased rapidly after treatment ceased, and by 25 d after treatment the CFU were similar in samples from both medicated and control fish populations. Of 325 isolates from fish selected for biochemical profiles, we identified a total of eight gram-positive and eight gram-negative genera. Bacillus spp. were common throughout sampling and were identified in samples of fish feed. Erythromycin-resistant, gram-positive bacteria were observed throughout the sampling in medicated and control fish. We identified seven gram-positive and two gram-negative genera in 74 selected isolates from control and erythromycin feeds. Our studies suggest that the aerobic microflora of the posterior intestine varies over time, and it is likely that few resistant genera of concern to human health are present.
Filamentous sulfur bacteria, Beggiatoa spp., in arctic marine sediments (Svalbard, 79°N)
Fjord sediments on the west coast of the arctic archipelago Svalbard were surveyed to understand whether large filamentous sulfur bacteria of the genus Beggiatoa thrive at seawater temperatures permanently near freezing. Two sediments had abundant populations of Beggiatoa, while at six sites, only sporadic occurrences were observed. We conclude that Beggiatoa, although previously unnoticed, are widespread in these arctic fjord sediments. Beggiatoa ranged in diameter from 2 to 52 ?m and, by those tested, stored nitrate in vacuoles at up to 260 mM. The 16S rRNA gene sequence of a 20-?m-wide filament is closely associated with other large, marine, nitrate-storing Beggiatoa. The Beggiatoa mostly occurred in the upper 2-5 cm of oxidized surface sediment between oxygen and the deeper sulfidic zone. In spite of a very low or an undetectable sulfide concentration, sulfate reduction provided abundant H2S in this zone. The total living biomass of Beggiatoa filaments at one study site varied over 3 years between 1.13 and 3.36 g m-2. Because of their large size, Beggiatoa accounted for up to 15% of the total prokaryotic biomass, even though the filament counts at this site were rather low, comprising <1/10 000 of the bacterial numbers on a cell basis.
Microbial colonization of different support materials used to enhance the methanogenic process
Microbial colonization of the different support materials used to enhance methane production in anaerobic digestors is rapid and occurs in the first 24 h of sludge incubation. Scanning electron microscopy studies reveal a predominant presence of filamentous methanogenic forms, closely resembling Methanosaeta (Methanothrix), which are located on the outer layer and in the bacterial framework of the biofilm. These findings are consistent with the results obtained from microbial counts using both the most probable number and epifluorescence microscopic techniques, which show an increase in the numbers of aceticlastic methanogens compared to other microbial groups involved, such as sulphate-reducing bacteria, the numbers of which are similar to those obtained under the initial conditions. Moreover, a sharp increase in the bacterial counts is observed by using the epifluorescence microscopic technique applied to homogenized samples, probably due to the count of bacteria released from the support materials. (orig.)
UF-1000i(TM) flow cytometry is an effective screening method for urine specimens
This study was undertaken to evaluate the UF-1000i(TM) (UF) flow cytometer to count urine constituents including bacteria. The objective was to screen urine samples and determine what white blood cell (WBC) and/or bacteria screening criteria would minimize the number of specimens cultured yet ensuring that all true positives were cultured. UF screening and culture on CHROMagar(TM) Orientation (CO) medium were performed on 2496 specimens. Various combinations of WBC/bacterial counts were assessed as screening criteria and correlated with significant growth on CO medium. A bacterial count of >=20 from UF gave an overall screening sensitivity of 92.6%, allowing 35% of specimens to be screened out and not cultured. The sensitivity was 99.2% and 85.0% for Gram-negative and Gram-positive organis...
The influence of storage on the farm and in dairy silos on milk quality for cheese production
Refrigerated storage of good-quality milk from a single cow resulted in moderate deterioration of its quality, low level of bacterial growth (standard plate and psychrotroph counts), and low small losses of curd yield. When milk was collected from farm bulk milk tanks and from dairy silos, its quality deteriorated faster than that of single-cow milk, resulting in high bacteria counts and high loss of curd yield, most of which was already apparent for the farm bulk milk tank. Statistical analyses did not reveal any significant interaction between bacterial growth, milk composition, somatic cell count, and curd yield loss, indicating that other mechanisms such as enzymatic activity might be responsible. From the comparison between the high-quality milk from an uninfected cows udder and the c...
An experiment was conducted under laboratory conditions to investigate the effect of increasing concentrations of fenitrothion (2, 10 and 200 mg a.i./kg soil), diuron (1.5, 7.5 and 150 mg a.i./kg soil) and thiram (3.5, 17.5 and 350 mg a.i./kg soil) on soil respiration, bacterial counts and changes in culturable fraction of soil bacteria. To ascertain these changes, the community structure, bacterial biodiversity and process of colony formation, based on the r/K strategy concept, EP- and CD-indices and the FOR model, respectively, were determined. The results showed that the measured parameters were generally unaffected by the lowest dosages of pesticides, corresponding to the recommended field rates. The highest dosages of fenitrothion and thiram suppressed the peak SIR by 15-70% and 20-80%, respectively, while diuron increased respiration rate by 17-25% during the 28-day experiment. Also, the total numbers of bacteria increased in pesticide-treated soils. However, the reverse effect on day 1 and, in addition, in case of the highest dosages of insecticide on days 14 and 28, was observed. Analysis of the community structure revealed that in all soil treatments bacterial communities were generally dominated by K-strategists. Moreover, differences in the distribution of individual bacteria classes and the gradual domination of bacteria populations belonging to r-strategists during the experiment, as compared to control, was observed. However, on day 1, at the highest pesticide dosages, fast growing bacteria constituted only 1-10% of the total colonies number during 48 h of plate incubation, whereas in remaining samples they reached from 20 to 40% of total cfu. This effect, in case of fenitrothion, lasted till the end of the experiment. At the highest dosages of fenitrothion, diuron and at all dosages of thiram the decrease of biodiversity, as indicated by EP- and CD-indices on day 1, was found. At the next sampling time, no significant retarding or stimulating effect was detected. However, in case of CD values the higher differences were observed. The significant impact of pesticides on the physiological state of soil bacteria was not found. They were generally in dormant state (lambda thiram on day 14) and prolonged retardation time of colony appearance (max. increase of t(r) value to 1.39 for fenitrothion on day 1) on agar plates were found. PMID:19444604
We tested the activity of epinecidin-1, a novel antimicrobial peptide structurally related to pleurocidin, in commercial cleaning solutions stored at 4 and 25^oC for 7 and 14 days. The peptide's activities against Enterococcus faecalis, Escherichia coli, Klebsiella oxytoca, Pseudomonas aeruginosa, Staphylococcus aureus, Propionibacterium acnes, and Candida albicans were measured in a minimum inhibitory concentration (MIC) determination, minimal bactericidal concentration (MBC) determination, disk diffusion test, and a count of the bacterial numbers. Exposure to epinecidn-1 in a cleaning solution following MIC value comparisons in the disk diffusion test and counts of bacterial numbers after 16, 24, 48, and 72h suggested that bacterial numbers were much lower than those treated with only co...
Air, Water, and Surface Bacterial Contamination in a University-Hospital Autopsy Room*
Abstract:- Today, little is known about the bacteriological environment of the autopsy room and its potential interest for medico-legal practices. Seven hundred fifty microbiological samples were taken from surface (n-=-660), air (n-=-48), and water (n-=-42) to evaluate it in a French University Forensic Department. Median bacterial counts were compared before and during autopsy for air samples, and before and after autopsy for surface samples, using Wilcoxon matched pairs signed ranks test. Bacterial identification relied on traditional phenotypic methods. Bacterial counts in the air were low before autopsy, increased significantly during procedure, and seemed more linked to the number of people in the room than to an important production of aerosol-containing bacteria. Despite cleaning, ...
Bacteriological Quality of Raw Milk Used for Production of a Brazilian Farmstead Raw Milk Cheese
Abstract The objective of this study was to evaluate the bacteriological quality of raw cow's milk utilized for the production of Traditional Minas Serro cheese, a Brazilian farmstead raw milk cheese. Raw milk samples were collected from six farmstead cheese operations manufacturing raw milk cheese from cow's milk. Coliform count (CC) and Escherichia coli counts were determined using Petrifilm? EC plates, and Staphylococcus aureus counts were determined using Petrifilm? Staph Express count plates. The standard plate count (SPC) was determined using plate count agar. The somatic cell count (SCC) was determined with a DeLaval cell counter. The detection of Listeria monocytogenes was based in the ISO 11290-1 protocol. A total of 165 samples were analyzed, and the SPC was 1.85?7.88 log CFU/mL....
RAGE - A rapid graphlet enumerator for large networks
Counting network graphlets (and motifs) was shown to have an important role in studying a wide range of complex networks. However, when the network size is large, as in the case of the Internet topology and WWW graphs, counting the number of graphlets becomes prohibitive for graphlets of size 4 and above. Devising efficient graphlet counting algorithms thus becomes an important goal. In this paper, we present efficient counting algorithms for 4-node graphlets. We show how to efficiently count the total number of each type of graphlet, and the number of graphlets adjacent to a node. We further present a new algorithm for node position-aware graphlet counting, namely partitioning the graphlet count by the node position in the graphlet. Since our algorithms are based on non-induced graphlet c...
Two-dimensional gel electrophoresis (2-DGE) mapping of genomic DNA and complementary DNA (cDNA) amplicons was attempted to analyze total and active bacterial populations within soil and activated sludge samples. Distinct differences in the number and species of bacterial populations and those that were metabolically active at the time of sampling were visually observed especially for the soil community. Statistical analyses and sequencing based on the 2-DGE data further revealed the relationships between total and active bacterial populations within each community. This high-resolution technique would be useful for obtaining a better understanding of bacterial population structures in the environment.
Two-dimensional gel electrophoresis (2-DGE) mapping of genomic DNA and complementary DNA (cDNA) amplicons was attempted to analyze total and active bacterial populations within soil and activated sludge samples. Distinct differences in the number and species of bacterial populations and those that were metabolically active at the time of sampling were visually observed especially for the soil community. Statistical analyses and sequencing based on the 2-DGE data further revealed the relationships between total and active bacterial populations within each community. This high-resolution technique would be useful for obtaining a better understanding of bacterial population structures in the environment.
Multiple indicator hidden Markov model with an application to medical utilization data.
Monthly counts of medical visits across several years for persons identified to have alcoholism problems are modeled using two-state hidden Markov models (HMM) in order to describe the effect of alcoholism treatment on the likelihood of persons to be in a 'healthy' or 'unhealthy' state. The medical visits can be classified into different types leading to multivariate counts of medical visits each month. A multiple indicator HMM is introduced, which simultaneously fits the multivariate Poisson counts by assuming a shared hidden state underlying all of them. The multiple indicator HMM borrows information across different types of medical encounters. A univariate HMM based on the total count across types of medical visits each month is also considered. Comparisons between the multiple indicator HMM and the total count HMM are made, as well as comparisons with more traditional longitudinal models that directly model the counts. A Bayesian framework is used for the estimation of the HMM and implementation is in Winbugs. PMID:18991318
Seven patients with pulmonary arteriovenous malformations (PAVMs) were studied and shunt values obtained using /sup 99/Tc/sup m/ MS were validated by simultaneous measurement of shunt fraction using the 100% oxygen method. By comparing radioactive counts in the injection dose to subsequent counts in the right kidney, which was taken as an index of systemic activity, accurate quantification of right-to-left shunt over a wide range of values was obtained (correlation coefficient against 100% oxygen method r=0.993). The comparison of right kidney counts with total lung counts and total lung counts with injected dose counts, also indicators of shunt fraction, correlated less well with the oxygen method (r=0.942 and r=0.88 respectively). Use of /sup 99/Tc/sup m/ labelled microspheres allows simple and precise measurement of right-to-left shunt in patients with PAVMs during routine isotope lung scanning.
Abstract in portuguese Todos os animais vivem em íntima associação com micro-organismos que desempenham importantes funções em seu desenvolvimento normal. Nos vertebrados, a mais populosa e complexa comunidade de micro-organismos reside no trato intestinal. O intuito do estudo foi quantificar, classificar e verificar morfologicamente a população microbiana intestinal de duas importantes espécies de peixes de água doce, o curimbatá (Prochilodus lineatus) e o cascudo cinza (Pterygoplich (more) thys anisitsi). As amostras foram coletadas por meio de raspagens da mucosa intestinal, diluídas seriadamente até 10-4, semeadas em placas contendo ágar soja tripticaseína (TSA) e ágar chocolate (AC) para contagem de bactérias totais e identificação morfológica por Gram, em aerobiose e em anaerobiose facultativa, respectivamente. As contagens de bactérias totais mostraram resultados que variaram entre 10³ e 10(4)ufc.mL-1. Os tipos morfológicos encontrados foram cocos, leveduras e bastonetes Gram negativos e positivos. Estudos adicionais sobre os padrões de colonização microbiana e a morfologia dos micro-organismos aderidos à mucosa intestinal foram possíveis com o uso da microscopia eletrônica de varredura (MEV), sendo encontradas formas variadas de micro-organismos, tais como leveduras, formas cocoides e bacilares flageladas e não flageladas. A microbiota intestinal do curimbatá e a do cascudo cinza provaram ser bastante diversas e populosas, com o predomínio de micro-organismos Gram negativos. Abstract in english All animals exist in intimate associations with microorganisms that play important roles in the hosts' normal development. In vertebrates, the most populous and complex community of microbes resides in the digestive tract.The aim of this research was to morphologically quantify, classify and verify the composition of intestinal microbiota of two species of freshwater fish, the Prochilodus lineatus and the Pterygoplichthys anisitsi. The samples were collected by scrapings (more) of intestinal mucosa, serially diluted to 10-4, plated on tryptic soy agar (TSA) and chocolate agar (CA) for total bacterial counting and morphological identification by Gram, in aerobiosis and facultative anaerobiosis conditions, respectively. In the total bacterial counting results ranged between 10³ to 10(4) cfu.mL-1. The morphological types found were cocci, yeasts and Gram negative and positive rods. Additional studies about patterns of microbial colonization and the morphology of the adhered microorganisms to the intestinal mucosa were possible using the scanning electron microscopy (SEM) and several forms of microorganisms, such as yeasts, cocci and bacillary shapes flagellated and non-flagellated were found. The intestinal microbiota of P. lineatus and P. anisitsi was diverse and populous, with a predominance of Gram negative microorganisms.
Abstract in portuguese A atividade de glicosidases durante a degradação do polissacarídeo extracelular (EPS) produzido por Anabaena spiroides foi detectada e quantificada utilizando-se MUF-substratos (MUF-monossacarídeos). O consumo total do polissacarídeo efetuou-se em duas fases, uma primeira de alta atividade enzimática que rapidamente consumiu 41% do polissacarídeo e uma segunda, mais lenta, que consumiu o polissacarídeo restante (59%). A mudança de fase coincidiu com a sucessão d (more) e uma população de bactérias cocóides por outra de bacilos. A biomassa bacteriana, quantificada por contagens de células, aumentou com a degradação do EPS. As atividades registradas através dos substratos 4-MUF-alfa-D- e 4-MUF-beta-D- glicosídeo foram mais altas quando comparadas aos demais substratos testados que foram: MUF-alfa-L-ramnopiranosídeo, MUF-beta-D-galactosídeo, MUF-alfa-D-manopiranosídeo, MUF-beta-D-fucosídeo, MUF-beta-D-manopiranosídeo, MUF-alfa-L-arabinopiranosídeo, e MUF-beta-L-fucosídeo. A fluorescência emitida a partir de cada um dos diferentes MUF-substratos foi, de modo geral, proporcional à concentração dos monossacarídeos correspondentes constituintes do polissacarídeo, um indício da susceptibilidade ao ataque enzimático microbiano do EPS produzido por A. spiroides. Abstract in english The activity of specific glycosidases during the degradation of the extracellular polysaccharide (EPS) produced by Anabaena spiroides was determined using MUF-substrates (MUF-monosaccharides). Polysaccharide degradation was found to occur in a two-phase process. The first consisted of high enzymatic activity that consumed 41% of the EPS at a relatively high rate, while the second consumed the remaining polysaccharide (59%) at a slower rate. A transition phase from the hig (more) her to the slower degradation rates was marked by a replacement of bacterial populations from coccoid to bacillus cells. During the degradation process, the bacterial biomass increased with the decrease of EPS, as revealed by bacterial cell counts. The enzymatic activity detected through the substrates MUF-alpha-D- and MUF-beta-D-glucoside was higher than that detected by other substrates tested. The remaining glycosides were MUF-alpha-L-rhamnopyranoside, MUF-beta-D-galactoside, MUF-alpha-D-mannopyranoside, MUF-beta-D-fucoside, MUF-beta-D-mannopyranoside, MUF-alpha-L-arabinopyranoside, and MUF-beta-L-fucoside. The fluorescence emitted by each MUF-substrate was proportional to the concentration of the corresponding monosaccharide in A. spiroides EPS. This demonstrates the susceptibility of EPS produced by A. spiroides to enzymatic attack by bacterial populations.
Abstract in portuguese Este trabalho analisou o efeito da temperatura e período de incubação e da diluição do inóculo, em dois meios de cultura, sobre a quantificação de bactérias totais e esporuladas. O crescimento quantitativo e qualitativo de bactérias totais e esporuladas depende tanto do meio de cultura, temperatura, diluição e tempo utilizados como da interação desses fatores. O meio de TSA apresentou maior contagem que o meio de Thorton de unidades formadoras de colônias ( (more) UFC) de bactérias totais mas não de Bacillus spp. As colônias crescidas no meio de TSA apresentaram maior tamanho e forma mais nítida. O cultivo à temperatura de 30°C propiciou maior número de UFC que a 25°C, sobretudo nos primeiros dias de incubação. O crescimento bacteriano correspondeu a uma equação de 3° grau. Dependendo do meio de cultura, da temperatura de incubação e da diluição, os períodos de máximo crescimento foram de 4,9 a 6,9 dias para as bactérias totais e de 4,4 a 7,2 dias para Bacillus spp. Embora tenham sido utilizadas diluições decimais dos inóculos, as proporções entre as contagens variaram de 6,3 a 10,0 vezes para as bactérias totais e de 2,0 a 7,0 para as esporuladas. Abstract in english This work studied the effect of the temperature and incubation time and of the inoculum dilution, in two culture media, on the quantification of total and sporulating bacteria. The quantitative and qualitative growth of total and sporulating bacteria depended on the growth medium, temperature, dilution and incubation time, as well as on the interaction of these factors. Tryptic Soil Agar medium presented a greater number of colony forming units (CFU) for total bacteria. H (more) owever, for Bacillus spp. there were higher counts on Thorton medium. Colonies grown on Tryptic Soy Agar medium were of larger size and had a more clearly defined shape. An incubation temperature of 30°C yielded more CFU than incubation at 25°C, especially during the first days of incubation. Bacterial growth was fit to a mathematical model and corresponded to a third degree equation. Depending on the growth culture medium, incubation temperature and dilution, periods of maximum growth were between 4.9 and 6.9 days for total bacteria and between 4.4 and 7.2 days for Bacillus spp. Although decimal inoculum dilutions were used, proportions between counts based on different conditions ranged from 6.3 to 10.0 times for total bacteria and from 2.0 to 7.0 times for sporulating bacteria.
Seasonal community and population dynamics of pelagic bacteria and archaea in a high mountain lake
The seasonal variations in community structure and cell morphology of pelagic procaryotes from a high mountain lake (Gossenkollesee, Austria) were studied by in situ hybridization with rRNA-targeted fluorescently labeled oligonucleotide probes (FISH) and image-analyzed microscopy. Compositional changes and biomass fluctuations within the assemblage were observed both in summer and beneath the winter ice cover and are discussed in the context of physicochemical and biotic parameters. Proteobacteria of the beta subclass (beta-proteobacteria) formed a dominant fraction of the bacterioplankton (annual mean, 24% of the total counts), whereas alpha-proteobacteria were of similar relative importance only during spring (mean, 11%). Bacteria of the Cytophaga-Flavobacterium cluster, although less abundant, constituted the largest fraction of the filamentous morphotypes during most of the year, thus contributing significantly to the total microbial biomass. Successive peaks of threadlike and rod-shaped archaea were observed during autumn thermal mixing and the period of ice cover formation, respectively. A set of oligonucleotide probes targeted to single phylotypes was constructed from 16S rRNA-encoding gene clone sequences. Three distinct populations of uncultivated microbes, affiliated with the alpha- and beta-proteobacteria, were subsequently monitored by FISH. About one-quarter of all of the beta-proteobacteria (range, 6 to 53%) could be assigned to only two phylotypes. The bacterial populations studied were annually recurrent, seasonally variable, and vertically stratified, except during the periods of lake overturn. Their variability clearly exceeded the fluctuations of the total microbial assemblage, suggesting that the apparent stability of total bacterioplankton abundances may mask highly dynamic community fluctuations. PMID:9797280
Low permeability regions sandwiched between high permeability regions such as clay lenses are difficult to treat using conventional treatment methods. Trace concentrations of contaminants such as non-aqueous phase liquids (NAPLs) remain trapped in these regions and over the time diffuse out into surrounding water thereby acting as a long term source of groundwater contamination. Bacterial chemotaxis (directed migration toward a contaminant source), may be helpful in enhancing bioremediation of such contaminated sites. This study is focused on simulating a two-dimensional dual-permeability groundwater contamination scenario using microfluidic devices and evaluating transverse chemotactic migration of bacteria from high to low permeability regions. A novel bi-layer polydimethylsiloxane (PDMS) microfluidic device was fabricated using photolithography and soft lithography techniques to simulate contamination of a dual- permeability region due to leakage from an underground storage tank into a low permeability region. This device consists of a porous channel through which a bacterial suspension (Escherchia Coli HCB33) is flown and another channel for injecting contaminant/chemo-attractant (DL-aspertic acid) into the porous channel. The pore arrangement in the porous channel contains a 2-D low permeability region surrounded by high permeability regions on both sides. Experiments were performed under chemotactic and non-chemotactic (replacing attractant with buffer solution in the non porous channel) conditions. Images were captured in transverse pore throats at cross-sections 4.9, 9.8, and 19.6 mm downstream from the attractant injection point and bacteria were enumerated in the middle of each pore throat. Bacterial chemotaxis was quantified in terms of the change in relative bacterial counts in each pore throat at cross-sections 9.8 and 19.6 mm with respect to counts at the cross-section at 4.9 mm. Under non-chemotactic conditions, relative bacterial count was observed to decrease at 9.8 mm and 19.6 mm cross-sections in low permeability regions due to dilution with the injectate from the non-porous channel (Figure 1). However, relative bacterial counts increased in the low permeability region at both downstream cross-sections under chemotactic conditions. A large increase in relative bacterial count in the pore throats just outside the low permeability region was also observed at both cross-sections (Figure 1). The bacterial chemotactic response was observed to decrease linearly with increasing Darcy velocity and at flow rate 0.220 mm/s the chemotactic effect was offset by the advective flow in the porous channel.
Abstract in spanish En los sistemas forestales, la hojarasca es generalmente la principal fuente de nutrientes para la vegetación y microorganismos, pudiendo variar éstos en relación a la biomasa y calidad de los materiales aportados por diferentes especies. Las raíces de los árboles ejercen influencia en el desarrollo y actividad de la microflora. El objetivo de este trabajo fue evaluar la influencia sobre el suelo de dos especies arbóreas implantadas, con distinta composición del re (more) siduo vegetal aportado al suelo. El suelo está clasificado como un Andisol y está ubicado en la Estación Forestal Trevelín, Chubut, Argentina, Lat. 43º Sur, Long 71º31´ Oeste. Se extrajeron muestras superficiales de suelo de dos parcelas de bosque con una especie dominante cada una: Pino radiata (Pinus radiata D. Don.) y Roble europeo (Quercus robur). Se determinó carbono orgánico, respiración microbiana, actividad deshidrogenasa, diversidad funcional de comunidades microbianas asociadas y se calculó el índice de diversidad de Shanon Weaver (H). Se cuantificaron bacterias totales, bacterias amilolíticas, actinomicetes y hongos. Los valores de respiración microbiana y carbono orgánico resultaron significativamente superiores en el suelo debajo de Roble. No se encontraron diferencias significativas entre valores de deshidrogenasa. Los recuentos de flora bacteriana total y de bacterias amilolíticas dieron significativamente superiores en el suelo asociado a Roble, mientras que los actinomicetes y hongos no mostraron diferencias significativas entre especies. El análisis de componentes principales mostró variaciones significativas en la fisiología de las comunidades microbianas asociadas a estas dos especies. El índice de diversidad H de la microflora fue significativamente mayor para Pino. Los residuos de Roble por ser una especie latifoliada y por lo tanto poseer menor contenido de sustancias recalcitrantes que una conífera, asociado al mayor desarrollo de bacterias totales y amilolíticas, podría favorecer una mayor descomposición del residuo vegetal aportado al suelo y explicar los mayores valores de carbono orgánico y respiración microbiana obtenidos. Abstract in english In forest systems, leaf litter is usually the main source of nutrients for the vegetation and microorganisms. Leaf litter composition may vary according to the biomass and quality of the materials produced by different species. Tree roots affect the development and activity of microflora. The aim of this study was to evaluate the influence of two implanted tree species, with different composition of plant residues, on the soil characteristics. The soil is classified as an (more) Andisol and is located in the Trevelín Forest Station, Chubut, Argentina, Lat. 43° S, Long 71º31' West. The samples were extracted from the surface soil of two forest plots with a dominant species each: Radiata Pine (Pinus radiata D. Don.) and European Oak (Quercus robur). The following analytical determinations were carried out on soil samples: organic carbon, microbial respiration, deshydrogenase activity, microbial count (bacterial communities, amilolytic, actinomyces and fungi) as well as the functional diversity of associated microbial communities. The Shannon-Weaver index (H) was calculated. The soil under Oak trees showed the highest values of microbial respiration, organic carbon and amilolytic and bacterial community counts. No significant differences were found in deshydrogenase activity, actinomyces and fungi counts between species. The principal component analysis showed significant variations in the physiology of microbial communities associated with these two tree species. The microorganism H diversity index was significantly greater for Pine. Plants residues of broadleaf species such as Oak have lower contents of recalcitrant substances than conifer species, and this fact, associated with the higher development of total and amylolytic bacteria, could result in an increase in the decomposition of plant residues in the soil and in higher organic carbon and microbial respiration values.
Abstract in spanish El objetivo del presente trabajo fue aislar diversidad de bacterias endófitas cultivables asociadas a raíces del pasto colosuana Bothriochloa pertusa (L) A. Camus en tres localidades del departamento de Sucre, Colombia. La diversidad de bacterias endófitas fue realizada mediante el aislamiento de colonias en medios de cultivos. La densidad poblacional fue estimada por conteo directo de colonias en placa y las características culturales de cada morfotipo fueron obtenid (more) as mediante observación de cada colonia formada. Se determinó la correlación diversidad, densidad poblacional y localidades, utilizando ANOVA y análisis de componentes principales o de correspondencia simple, mediante el programa estadístico R, 2009 (4,5). Fueron muestreadas 20 fincas por lo-calidad; se observó presencia de diversos morfotipos de bacterias endófitas. Se encontró diferencias significativas entre diversidad (morfotipos), densidad poblacional (UFC. raíz-1) y localidades. La diversidad de bacterias endófitas representa apenas una pequeña fracción de la diversidad total existente en la naturaleza, siendo escasas las informaciones que se tienen de la presencia de estos microorganismos en agroecosistemas específicos, razón por lo cual este trabajo se convierte en la primera evidencia de asociación entre bacterias endófitas y raíces del pasto colosuana en Colombia. Abstract in english The objective of this study was to isolate endophytes diversity of culturable bacteria associated with grass roots colosuana Bothriochloa pertusa (L) A. Camus in three localities of the department of Sucre, Colombia. Endophytes bacterial diversity was performed by isolation of colonies on media culture. The population density was estimated by direct counting of colonies on plate and cultural characteristics of each morphotype were obtained by observation of each colony ma (more) de. We determined the correlation diversity, population density and locations, using ANOVA and principal component analysis or simple correspondence, using the statistical program R, 2009 (4.5). 20 farms livestock were sampled by locality, it was observed the presence of various bacterial morphotypes endophytes.We found significant differences between diversity (morphotypes), population density (UFC.raíz-1) and locations. The diversity of bacterial endophytes represents only a small fraction of the total diversity present in nature; being little information we have of the presence of these microorganisms in specific agroecosystems, which is why this work becomes the first evidence of association between bacteria and roots of grass endophytes colosuana in Colombia.
Abstract in portuguese O caldo de cana é recém-preparado e comercializado por manipuladores sem tratamento térmico em São Carlos, São Paulo, Brasil. Vinte e quatro amostras da bebida obtidas em condição de consumidor nos pontos de venda foram avaliadas utilizando-se métodos convencionais na determinação de bactérias heterótrofas, contagens de coliformes totais e termo-tolerantes, Salmonella spp. e parasitas. Observou-se que 25% das amostras apresentaram condições sanitárias insat (more) isfatórias, com níveis de coliformes termo-tolerantes superiores aos permitidos pelos padrões brasileiros. Salmonella spp. e parasitas não foram detectados em nenhuma amostra. Em 37% das mãos de manipuladores do produto detectou-se coliformes termo-tolerantes e as contagens de organismos heterótrofos atingiu valores de 2,0x103UFC/por mão. Em uma amostra de mão detectou-se a presença de Escherichia coli e ausência de Salmonella spp. Utilizaram-se entrevistas por meio de questionários com os vendedores e 62% destes não admitiram conhecimento ou adoção de quaisquer práticas higiênico-sanitárias para manipulação de alimentos. Abstract in english Fresh sugarcane juice is sold by street vendors without any heat treatment in São Carlos, São Paulo, Brazil. Twenty-four samples of point-of-sale juice were tested by standard methods to determine heterotrophic bacteria, total and thermo-tolerant coliform counts, Salmonella, and parasites in the juice. 25% of samples showed poor sanitary conditions, with thermo-tolerant coliform levels higher than allowed by Brazilian standards. Salmonella spp. and parasites were absent (more) in all samples. Thermo-tolerant coliforms were detected on the hands of 37% of juice handlers, and heterotrophic bacterial counts reached 2.0 x 10³ cfu/per hand. Escherichia coli was detected in one hand sample, and no Salmonella spp. was detected. Screening questionnaires were used to interview the vendors, and 62% of interviewees were either unfamiliar with or failed to adopt adequate hygiene for food handling.
We compute the liquid scintillation counting efficiency for 137Cs+137mBa and ''129 I taking into account the scintillator chemical composition. We consider the beta transition shape factors for the for bidden beta transitions of these nuclides, and the effects of 137mBa and 129mXe half-lives on the total counting efficiency. (Author) 8 refs.
Volume and type of medium, carbohydrate concentration, carbohydrate ratios, and inoculum level were investigated as possible factors influencing total colony counts of anaerobic rumen bacteria obtained in roll tubes (18 by 150 mm). Colony counts were lower when the rumen fluid was clarified by centr...
Fingerprint Ridge Count: A Polygenic Trait Useful in Classroom Instruction.
Describes the use of the polygenic trait of total fingerprint ridge count in the classroom as a laboratory investigation. Presents information on background of topic, fingerprint patterns which are classified into three major groups, ridge count, the inheritance model, and activities. Includes an example data sheet format for fingerprints. (RT)
The microbiota of ten seeds and ready-to-eat sprouts produced thereof was characterized by bacteriological culture and denaturing gradient gel electrophoresis (DGGE) of amplified DNA fragments of the 16S rRNA gene. The predominant bacterial biota of hydroponically grown sprouts mainly consisted of enterobacteria, pseudomonades and lactic acid bacteria (LAB). For adzuki, alfalfa, mung bean, radish, sesame and wheat, the ratio of these bacterial groups changed strongly in the course of germination, whereas for broccoli, red cabbage, rye and green pea the ratio remained unchanged. Within the pseudomonades, Pseudomonas gesardii and Pseudomonas putida have been isolated and strains of the potentially pathogenic species Enterobacter cancerogenes and Pantoea agglomerans were found as part of the main microbiota on hydroponically grown sprouts. In addition to the microbiota of the whole seedlings, the microbiota of root, hypocotyl and seed leafs were examined for alfalfa, radish and mung bean sprouts. The highest and lowest total counts for aerobic bacteria were found on seed leafs and hypocotyls, respectively. On the other hand, the highest numbers for LAB on sprouts were found on the hypocotyl. When sprouting occurred under the agricultural conditions, e.g. in soil, the dominating microbiota changed from enterobacteria to pseudomonades for mung beans and alfalfa sprouts. No pathogenic enterobacteria have been isolated from these sprout types. Within the pseudomonades group, Pseudomonas jessenii and Pseudomonas brassicacearum were found as dominating species on all seedling parts from soil samples. In practical experiments, a strain of P. jessenii was found to exhibit a potential for use as protective culture, as it suppresses the growth of pathogenic enterobacteria on ready-to-eat sprouts. PMID:17512686
Evaluation of somatic cell count thresholds to detect subclinical mastitis in Gyr cows.
The objectives of this study were (1) to determine the sensitivity (Se) and specificity (Sp) of somatic cell count (SCC) thresholds to identify subclinical mastitis in Gyr cows caused by major and minor pathogens; (2) to study the effects of month of sampling, rear or front mammary quarters, herd, intramammary infection (IMI), and bacterial species on SCC at quarter level; and (3) to describe the prevalence of IMI in Gyr cows in commercial dairy herds. In total, 221 lactating Gyr cows from 3 commercial dairy farms were selected. Milk samples were collected from individual quarters once a month for 1 yr from all lactating cows for SCC and bacteriological analysis. Mammary quarters were considered the experimental units and the SCC results were log(10)-transformed. Four SCC thresholds (100, 200, 300 and 400 × 10(3) cells/mL) were used to determine Se and Sp to identify infected mammary quarters. The overall prevalence of IMI in quarter milk samples of Gyr cows was 49.8%, and the prevalence of minor pathogens was higher (31.9%) than that of major pathogens (17.8%). Quarter samples with microbial isolation presented higher SCC compared with negative samples. Sensitivity and Sp of selected SCC thresholds varied according to the group of pathogen (major and minor) involved in the IMI definition. Sensitivity increased and Sp decreased when mammary quarters with only major pathogens isolation were considered positive. The use of a single SCC analysis to classify quarters as uninfected or infected in Gyr cows may not be a useful test for this breed because Se and Sp of SCC at the studied thresholds were low. The occurrence of IMI and the bacterial species are the main factors responsible for SCC variation in mammary quarters of Gyr cows. Milk samples with major pathogens isolation elicited higher SCC than those with minor pathogens. PMID:21854914
Effect of dehairing operations on microbiological quality of swine carcasses.
To develop a hazard analysis and critical control point plan for food processing operations, critical control points must be determined. Swine slaughtering and dressing operations were investigated to establish their critical control points. We monitored the microbiology of swine carcasses by surface swabbing carcass bellies at various steps during the process and by quantitating total aerobic plate count (APC) and coliforms. Starting with a dehaired carcass, the sequential steps monitored included presingeing, postsingeing, polishing, and chilling. Initial results indicate that singeing and chilling substantially reduced the levels of APC and coliforms, whereas polishing increased their levels. The hygienic characteristics of individual operations involved in dressing swine carcasses were then evaluated in the second experiment. A set of 40 randomly selected carcasses leaving singeer, polisher, shaver, and washer were sampled. Carcasses were heavily contaminated during the final polishing procedure, and the APC increased threefold compared with prepolishing levels. Washing reduced the bacterial numbers by 69%. To reduce the microbial load on swine carcasses, final polishing and manual shaving steps were not used during the dressing operation on a set of 90 carcasses. APCs on singed carcasses were reduced from 1.34 to -0.15 log10 CFU/cm2 when the final polisher and manual shavers were not used. However, carcasses were subsequently recontaminated with bacteria after evisceration, and the APCs were similar (P > 0.05) regardless of whether the final polishing and manual shaving steps were used, averaging 1.30 and 1.46 log10 CFU/cm2. These results indicated that individual operations can be identified as critical control points, appropriate limits can be set and monitored in a hazard analysis and critical control point system, and steps where further changes to reduce bacterial levels may be needed for swine slaughtering plants. PMID:10606156
The effect of paenimyxin, a new biopesticide produced by Paenibacillus sp. strain B2, on the density of soil bacterial communities was assessed by colony counting and by 16S rDNA and nirK quantitative polymerase chain reaction (PCR). Paenimyxin had a negative effect on the bacterial colony-forming unit (CFU) number, which was significantly reduced 2 and 4 days after treatment. The effect of paenimyxin on cultivatable bacteria was negligible 7 days after treatment. Approximately 107 16S rDNA sequences per gram of soil (dry weight) were detected by quantitative PCR in all samples. Paenimyxin did not affect the quantification of 16S rDNA or of the denitrifying bacterial community. In addition, RISA fingerprinting showed that the genetic structure of the bacterial communities was significantly...
The main objective of this study was to assess the impact of pollution on seabed bacterial diversity, structure and activity in the Port of Livorno. Samples of seabed sediments taken from five selected sites within the port were subjected to chemical analyses, enzymatic activity detection, bacterial count and biomolecular analysis. Five different statistics were used to correlate the level of contamination with the detected biological indicators. The results showed that the port is mainly contaminated by variable levels of petroleum hydrocarbons and heavy metals, which affect the structure and activity of the bacterial population. Irrespective of pollution levels, the bacterial diversity did not diverge significantly among the assessed sites and samples, and no dominance was observed. The ...
The pharmacokinetics (PK) and pharmacodynamics (PD) of marbofloxacin were established in calves for six strains of each of the pneumonia pathogens Mannheimia haemolytica and Pasteurella multocida. The distribution of marbofloxacin into inflamed (exudate) and non-inflamed (transudate) tissue cage fluids allowed comparison with the serum concentration-time profile. To establish the PD profile, minimum inhibitory concentration (MIC) was determined in Mueller-Hinton broth (MHB) and calf serum. Moderately higher MICs were obtained for serum compared to MHB. An initial integration of PK-PD data established C(max)/MIC ratios of 45.0 and AUC(24h)/MIC values of 174.7h, based on serum MICs, for both bacterial species. Using bacterial time-kill curves, generated ex vivo for serum marbofloxacin concentrations, PK-PD modelling established three levels of growth inhibition: AUC(24h)/MIC ratios for no reduction, 3 log(10) and 4 log(10) reductions in bacterial count from the initial inoculum count were 41.9, 59.5 and 68.0h for M. haemolytica and 48.6, 64.9 and 74.8h for P. multocida, on average respectively. Inter-strain variability for 3 log(10) and 4 log(10) reductions in bacterial count was smaller for P. multocida than for M. haemolytica. In conjunction with literature data on MIC(90) values, the present results allowed prediction of dosages for efficacy for each organism for the three levels of growth inhibition. PMID:23084327
OBJECTIVES: This study aims to assess the effects of rinsing with zinc- and chlorhexidine-containing mouth rinse with or without adjunct tongue scraping on volatile sulfur compounds (VSCs) in breath air, and the microbiota at the dorsum of the tongue. MATERIAL AND METHODS: A randomized single-masked controlled clinical trial with a cross-over study design over 14 days including 21 subjects was performed. Bacterial samples from the dorsum of the tongue were assayed by checkerboard DNA-DNA hybridization. RESULTS: No halitosis (identified by VSC assessments) at day 14 was identified in 12/21 subjects with active rinse alone, in 10/21with adjunct use of tongue scraper, in 1/21 for negative control rinse alone, and in 3/21 in the control and tongue scraping sequence. At day 14, significantly lower counts were identified only in the active rinse sequence (p?VSC scores were correlated with several bacterial species. The use of a tongue scraper combined with active rinse did not change the levels of VSC compared to rinsing alone. CONCLUSIONS: VSC scores were not associated with bacterial counts in samples taken from the dorsum of the tongue. The active rinse alone containing zinc and chlorhexidine had effects on intra-oral halitosis and reduced bacterial counts of species associated with malodor. Tongue scraping provided no beneficial effects on the microbiota studied. CLINICAL RELEVANCE: Periodontally healthy subjects with intra-oral halitosis benefit from daily rinsing with zinc- and chlorhexidine-containing mouth rinse. PMID:22573244
Counting bacteria using functionalized gold nanoparticles as the light-scattering reporter.
A simple and rapid bacterial counting method was developed based on dark-field light-scattering imaging of bacteria and gold nanoparticle (AuNP) reporter simultaneously. Commercially available DH5? E. coli strain was used as the model bacterium to demonstrate the feasibility of the proposed method. With antibody-conjugated AuNPs, the simple sample treatment and target E. coli strain recognition can be finished within 15-30 min, with a detection limit of 2-6 × 10(4) colony forming unit per milliliter (CFU/mL). By using 90 nm AuNPs as the light-scattering signal reporter, the bacterial recognition and counting can be easily performed with low-cost instrumentation such as an entry-level dark-field microscope setup and a common tungsten lamp as the light source. An automatic image analysis algorithm was also developed to facilitate robust and fast bacterial counting. The preliminary results of water, milk, and fruit juice sample analysis showed that this simple, fast, and cost-effective method can be easily adopted for routine bacterial detection. PMID:23035847
Abstract in spanish El objetivo de este estudio fue medir la formación de histamina y los cambios microbiológicos en Chalcalburnus tarichi fresco procedente del lago Van y almacenado a 4 °C por un período de hasta 15 días. Muestras del músculo de los pescados fueron tomadas en intervalos de tiempo (días 1, 5, 7, 9,11, 13 y 15) durante el almacenaje. El contenido de la histamina fue determinado usando un método espectrofluorométrico y el conteo total y características de las Enteroh (more) acteriaceae y Pseudomonas spp. presentes en las muestras fueron establecidas por procedimientos microbiológicos estándares. La concentración inicial de histamina era de 27,5 mg/kg, aumentando gradualmente hasta 134,38 mg/kg en el día 15. El conteo bacteriano viable total varió de 8,0x10² a 9,0x10(9) ufc/g. Las Enterohacteriaceae estaban en el rango de 2,0 x 10² a 6,5 x 10(9) ufc/g, mientras las Pseudomonas spp. estaban entre 3,0 x 10² a 7,3 x 10(9) ufc/g Abstract in english Histamine accumulates in food via microbial decarboxylation of histidine. Small amounts of histamine naturally occurring in food under normal circumstances do not pose a public health hazard. Certain microbial species such as Enterobacteriaceae and Pseudomonas spp. have considerable capacity for histamine formation and can proliferate during handling or processing of foodstuffs, possibly elevating the histamine content to a harmful level. The objective of this study was t (more) o measure the formation of histamine and microbiological changes in fresh Chalcalburnus tarichi from Van lake and stored at 4 °C for up to 15 days. Fish muscle samples were taken on day 1,3,5,7,9,11,13 and 15 of experiment, during storage. Histamine content was determined using a spectrofluorometric method and the total count and features of Enterobacteriaceae and Pseudomonas spp. present in the samples were established by standard microbiological procedures. The initial concentration of histamine was 27.5 mg/kg, increasing gradually up to 134.38 mg/kg on day 15. Total viable bacterial count varied from 8.0 x 10² to 9.0x10(9) cfu/g. Enterobacteriaceae was in the 2.0 x 10² to 6.5 x 10(9) cfu/g range, while Pseudomonas spp. was in the 3.0 x 10² to 7.3 x 10(9) cfu/g range
Microbiological analysis and starter culture growth in retentates.
Pasteurized skim milk was concentrated by UF to 2-, 4-, and 5-fold. The retentates were evaluated for microbiological quality, heat treatments to inactivate microorganisms, and lactic acid bacterial starter culture activity. Aerobic mesophilic bacterial counts in raw milk decreased from an initial 1.4 x 10(6) to 3.9 x 10(2) cfu/ml after pasteurization. During UF, counts increased from 3.9 x 10(2) cfu/ml UF, counts increased from 3.9 x 10(2) cfu/ml in pasteurized milk to 1.4 x 10(3), 1.4 x 10(4), and 1.8 x 10(4) cfu/ml in 2-, 4- and 5-fold retentates, respectively. Psychrotrophic bacterial counts decreased from 9.9 x 10(5) cfu/ml in raw milk to 3.7 x 10(1) cfu/ml in pasteurized milk and gradually increased to 1.0 x 10(2), 2.5 x 10(2), and 1.4 x 10(3) cfu/ml in 2-, 4-, and 5-fold retentates, respectively. Thermophilic bacterial counts remained less than 10 cfu/ml in all samples. Skim milk and retentates inoculated with five starter cultures at 1% failed to decrease the pH below 4.6 in (2-, 4- and 5-fold). The 4- and 5-fold retentates inoculated with Lactococcus lactis spp. cremoris or Lactococcus lactis spp. lactis cultures were partially coagulated with pH greater than 5.6. In general, the pH of retentates remained higher than that of skim milk. Clotting of uninoculated samples was observed, and a spore-forming contaminant, tentatively characterized as Bacillus cereus and capable of clotting milk at a pH greater than 6, was isolated from the clotted samples.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1744259
Total lymphoid irradiation in multiple sclerosis: blood lymphocytes and clinical course
We have found a significant relationship between blood lymphocyte count and prognosis in 45 patients receiving either total lymphoid irradiation or sham irradiation for chronic progressive multiple sclerosis. Patients with sustained lymphocyte counts less than 900 mm-3 for prolonged periods after treatment showed less rapid progression over the ensuing 3 years than did patients with multiple sclerosis who had lymphocyte counts above this level (p less than 0.01). Our results suggest that a simple laboratory test, the absolute blood lymphocyte count, may serve as a valuable barometer for monitoring the amount of immunosuppressive therapy needed to prevent progression in patients with multiple sclerosis, and possibly other autoimmune diseases.
The influence of subsample size on counting precision and estimates of taxa richness is documented for a freshwater zooplankton biomonitoring program. Subsample variability was related to subsample size. The mean and median coefficient of variation for cladocera and copepoda were below 30% at counts of 50-100 individuals. Jaccard's similarity coefficient stabilized at counts of 100-150 individuals as did the total number of zooplankton taxa identified. These data suggest that counting more organisms in subsamples or more than one subsample per sample may do relatively little to better characterize samples.
Antibiotic therapy for bacterial meningitis in children in developing countries.
We carried out a study to investigate the effectiveness of chloramphenicol alone as a treatment for bacterial meningitis. A total of 70 consecutive children aged > 3 months with bacterial meningitis, who had been admitted to the paediatric hospital of the All India Institute of Medical Sciences, wer...
Inulin is a well-known fructose-based prebiotic which has been shown to stimulate the growth of bifidobacteria, a bacterial group generally considered beneficial for intestinal health. In the present study, we analyzed inulin-associated shifts in the total bacterial community of wild-type mice and m...
Translocation of indigenous microflora in an experimental model of sepsis.
Translocation of viable bacteria from gut to bloodstream and other sterile body sites during shock has been demonstrated in several experimental and clinical studies. The factors causing translocation and its incidence at different stages of shock are not known. The aim of the study was to evaluate the importance of several factors causing translocation of indigenous microflora in an experimental model of septic shock based on intraperitoneal Escherichia coli sepsis in rats. Counts of inoculated E. coli and translocated bacteria in different locations, gut morphology and haematological values were evaluated at different stages of sepsis. Sepsis developed in all animals and E. coli achieved the highest counts in blood 6 h after inoculation. Translocation was commonest at 6 and 12 h after inoculation. Frequently translocating bacteria were lactobacilli, bifidobacteria, bacteroides and peptostreptococci. In early sepsis, translocation was associated with high E. coli counts in blood, yet in late sepsis the opposite correlation was present. Low infiltration by neutrophils in the ileum and decreased mitotic activity in the colon were associated with a high translocation rate. In early sepsis, translocation was associated with low lymphocyte counts, but in late sepsis, with low neutrophil counts. Translocation of bacteria (including anaerobes) that colonise the gut in high counts takes place during sepsis. Putative influencing factors such as activity of the primary disease (bacterial counts in blood), gut morphology or haematological values seem to have different impacts on translocation, depending on the stage of the disease. PMID:10798556
The sensitivity of creeping bentgrass (Agrostis palustris Huds.) to the extreme heat found in the southeastern United States has led to the development of new greens-management methods. The purpose of this study was to examine the effects of subsurface aeration and growth regulator applications on soil microbial communities and mycorrhizal colonization rates in a creeping bentgrass putting green. Two cultivars (Crenshaw and Penncross), a growth regulator (trinexapacethyl), and subsurface aeration were evaluated in cool and warm seasons. Total bacterial counts were higher in whole (unsieved) soils than in sieved soils, indicating a richer rhizosphere soil environment. Mycorrhizal infection rates were higher in trinexapac-ethyl (TE) treated plants. High levels of hyphal colonization and relatively low arbuscule and vesicle occurrence were observed. Principal components analysis of whole-soil fatty acid methyl ester (FAME) profiles indicated that warm-season microbial populations in whole and sieved soils had similar constituents, but the populations differed in the cool season. FAME profiles did not indicate that subsurface aeration and TE application affected soil microbial community structure. This is the first reported study investigating the influences of subsurface aeration and TE application on soil microorganisms in a turfgrass putting green soil.
An increase in the incidence of debilitated loggerhead sea turtle (Caretta caretta) strandings in the southeastern United States has been observed in recent years. These turtles are characterized by emaciation and heavy burdens of external and internal parasites, and bacterial infections, but the underlying cause of their condition is unknown. To investigate further the causes of these strandings, a health assessment was performed on stranded, debilitated loggerhead turtles, and contaminant concentrations in various tissues were compared to those from healthy turtles. This portion of the study investigated the potential role of mercury (Hg) toxicity in the debilitated condition described above. Hematocrit, total protein, albumin, globulin, glucose, calcium, lymphocyte counts, heterophil:lymphocyte ratios, aspartate aminotransferase, uric acid, sodium, and chloride were altered in debilitated loggerheads relative to healthy animals. However, none of the aforementioned health indicators correlated with Hg concentrations in either red blood cells (RBCs) or plasma. The Hg concentration in RBCs was 129+/-72 (mean+/-standard deviation) times higher than in plasma, causing a significant dilution of Hg in whole blood due to extreme anemia. Mercury concentrations in RBCs (73.7+/-21.2 ng/g) and scutes (455+/-57 ng/g) from debilitated turtles were similar to or lower than those reported for healthy animals, indicating no elevation in Hg exposure before and during the progression of this condition. These findings suggest that Hg toxicity does not play a role in the debilitated loggerhead condition observed in the southeastern United States. PMID:20090024
Reservoirs of nosocomial pathogens in neonatal intensive care unit.
A total of 256 swabs taken from different areas of neonatal intensive care units (ICU) in KCG Hospital and AMC Hospital, Bangalore were bacteriologically investigated for prevalence, source and spread of nosocomial bacteria. Culture studies revealed growth in 217 (84.8%) swab samples indicating considerable contamination of different areas of the units and sources of infection. Klebsiella pneumoniae (27.3%) was the predominant organism followed by Esch coli (16.8%), Staph aureus (11.7%), Staph epidermidis and Pseudomonas aeruginosa (10.2%), enterococcus and proteus (4.7%), Citrobacter freundi (3.5%) and Clostridium tetani (2.4%) isolated from the equipment, cradles, other inanimate objects and environmental surfaces. Out of 312 isolates, monobacterial prevalence was 43.6% in contrast to polybacterial prevalence of 56.4%. Klebsiella pneumoniae (74.3%) was the predominant monobacterial isolate. The indoor air of the units was found to carry common nosocomial bacteria of 4 or more different bacterial species at dangerous levels as observed by colony counts of 15 to 30 on exposed blood agar plates. Almost all sources in ICU revealed the presence of Klebsiella Pneumoniae, Esch coli, pseudomonas and staphylococcus thus forming the potential reservoirs of nosocomial infections to babies and this could be attributed to overcrowding, poor ventilation system and failure to follow basic principles of strict protective barrier nursing. PMID:9212573
Bacterial biofilms on long-term catheters are a major source of infection. Exposure to ultraviolet C (UVC - 265 nm) light was shown in an earlier study to reduce the number of bacteria substantially on ex vivo treated urinary patient catheters. Very large doses (long treatment times) should, however, be applied to obtain 99.9% disinfection rates. The major reason was that besides cells the mature biofilm contained absorbing and scattering particulates, which made the biofilm opaque. The potential of UVC light emitting diodes (LED) for disinfection purposes in catheter-like tubes contaminated with biofilm was investigated. It was shown that UVC light propagation was possible through both Teflon and catheter tubes (silicone). The disinfection efficiency of the diodes was demonstrated on tubes contaminated artificially with a Pseudomonas aeruginosa biofilm. The tubes were connected to a flow system and biofilms were produced during a 3 day period. Tubes in lengths of 10 (Teflon, silicone) and 20 cm (Teflon) werecontaminated. Tubes for control and for UVC treatment were contaminated in parallel. Biofilms were sampled from the total inner surface of the tubes. Colony counts on the control samples were in the range of 5 x 10(5)-1.3 x 10(9) CFU ml(-1), with disinfection rates in the range 96-100%. The applied UVC doses corresponded to treatment times between 15 and 300 min. Disinfection (100%) was obtained in 10 cm Teflon tubes exposed for 30 min (detection limit
[Denitrifying bacteria of constructed wetland system based on nitrous oxide reductase gene (nosZ)].
A horizontal subsurface flow constructed wetland was used to treat micro-pollution surface water and its effluent flowed into a landscape river as the water supplement. The abundance of the nitrous oxide reductase gene nosZ and 16S rDNA was investigated for the rhizosphere soil of the constructed wetland and the sediment of the landscape river by quantitive PCR. The diversity and similarity of denitrifiers were studied by using PCR-DGGE technique targeting the functional gene nosZ. The quantitive PCR results showed that the copy number of 16S rDNA and nosZ gene of the rhizosphere soil of the constructed wetland and the sediment of the landscape river were 1.91E + 07, 1.26E + 06 and 2.68E + 07, 8.37E + 05 copies x ng(-1) (by DNA), and 1.45E + 11, 9.31E + 09 and 5.31E + 11, 1.45E + 10 copies x g(-1) (by dry soil), respectively. Generally, the total bacterial count and denitrifiers in the sediment of the landscape river was higher than that of the constructed wetland, but the relative abundance of nosZ of the latter (3.8% - 10.1%) was significantly higher than that of the former (1.7% - 4.1%). There was low similarity between the two niches in cluster analysis. The predominant species of rhizosphere soil were mainly contained Rhodobacearales, Rhizobiales and Burkholderiales, although the predominant species of sediment were uncultured bacteria. PMID:22720582
Molecular identification of intestinal microflora in Takifugu niphobles.
We investigated the intestinal microflora of coastal fish including Takifugu niphobles using both culture techniques and library cloning. As a result, the numbers of bacteria appeared on agar media were 1.0x10(4) to 1.4x10(9) CFU/g (colony forming units/gram), whereas those of total bacteria stained with 4',6-diamidino-2-phenylindole were 4.7x10(10) to 1.9x10(11) cells/gram, irrespective of different fish species. In addition, the culture technique showed that the intestinal microflora in all specimens was mainly composed of the genus Vibrio. In contrast, the direct count method showed that spirochaetes with length of 2.5-4.5 mum were present in the intestinal contents of T. niphobles at high densities, whereas such bacteria could not be detected in those of other fish species. Library cloning yielded the sequences of 16S rRNA genes that were divided into seven taxonomic categories of bacteria including Actinobacteria, Bacilli, Clostridia, Gammaproteobacteria, Mollicutes, Spirochaetes and an unclassified bacterial group. These results demonstrate that the molecular diversity of the intestinal bacteria in T. niphobles based on the clone library method reflects the direct observation by fluorescence microscopy to some extent. PMID:20483242
We collected urban soil samples impacted by polycyclic aromatic hydrocarbons (PAHs) from a sorbent-based remediation field trial to address concerns about unwanted side-effects of 2% powdered (PAC) or granular (GAC) activated carbon amendment on soil microbiology and pollutant biodegradation. After three years, total microbial cell counts and respiration rates were highest in the GAC amended soil. The predominant bacterial community structure derived from denaturing gradient gel electrophoresis (DGGE) shifted more strongly with time than in response to AC amendment. DGGE band sequencing revealed the presence of taxa with closest affiliations either to known PAH degraders, e.g. Rhodococcus jostii RHA-1, or taxa known to harbor PAH degraders, e.g. Rhodococcus erythropolis, in all soils. Quantification by real-time polymerase chain reaction yielded similar dioxygenases gene copy numbers in unamended, PAC-, or GAC-amended soil. PAH availability assessments in batch tests showed the greatest difference of 75% with and without biocide addition for unamended soil, while the lowest PAH availability overall was measured in PAC-amended, live soil. We conclude that AC had no detrimental effects on soil microbiology, AC-amended soils retained the potential to biodegrade PAHs, but the removal of available pollutants by biodegradation was most notable in unamended soil. PMID:22455603
Two hundred and two strains of lactic acid bacteria (LAB) isolated from digestive tracts of cultivated and wild adult shrimp, including Litopenaeus vannamei, Metapenaeus brevicornis and Penaeus merguiensis were selected based on their antibacterial activity against Vibrio harveyi. LAB strain of MRO3.12 exhibiting highest reduction of V. harveyi was identified as Lactobacillus plantarum MRO3.12 based on the nucleotide sequence of its 16S rDNA, which showed 99% (780/786 bp) homology to L. plantarum strain L5 (GenBank accession number DQ 239698.1). Co-cultivation of V. harveyi and L. plantarum MRO3.12 showed complete reduction of V. harveyi at 24 h under aerobic and anaerobic conditions, whereas L. plantarum increased from 5.29 to 9.47 log CFU ml(-1). After 6-week feeding trial with L. plantarum supplemented diet, white shrimp (L. vannamei) exhibited significant differences (p shrimp showed higher level of 5.0 ± 0.14 log CFU/g than the non-supplemented ones (3.34 ± 0.21 log CFU/g). However, total bacterial and non-fermenting vibrios counts decreased in shrimps fed on L. plantarum. Ten days after infection with V. harveyi (5.3-5.5 log CFU ml(-1)), significant survival (p shrimp, while only 67% survival was observed in the control. PMID:22126856
Ciliates in rapid gravity filters of waterworks exploiting deep groundwaters.
Potable water is increasingly produced from deep (>100 m) tertiary groundwaters which often are completely reduced and contain high amounts of ammonium, methane, and hydrogen sulphide. They thus require special treatment which includes oxygenation and removal of the reduced contaminants by the biofilm developing in rapid gravity filters. The biofilm is heavily colonized with ciliates and microinvertebrates. A total of 38 species of ciliates was found in 42 samples taken from 4 waterworks in Germany during a period of 2 years. Only six species occurred in high numbers and in more than half of the samples: Acineria uncinata, Aspidisca lynceus, Cinetochilum margaritaceum, Colpidium colpoda, Glaucoma scintillans, and Holosticha pullaster. Five to thirteen species occurred per sample, and up to 6,000 individuals ml-1 biofilm were counted. There was a considerable fluctuation in the number of species and individuals, which could not be related to specific process parameters. The number of species and individuals decreased markedly from the filter surface to its centre. Colonization of the filters very likely occurs randomly via impure surface waters. The ciliate communities found consist mainly of alphamesosaprobic to polysaprobic species and thus closely resemble those known from activated-sludge processes. This is explained by the specific conditions near and in the biofilm, which is probably microaerobic and highly productive, providing microaerobic bacterial feeders with copious food. Obviously, it is the microenvironment which determines the occurrence of certain species. Thus, future research on the autecology of the indicator species used in the saprobic system should concentrate on their microenvironments. PMID:8820661
A multi-proxy study of anaerobic ammonium oxidation in marine sediments of the Gullmar Fjord, Sweden
Anaerobic ammonium oxidation (anammox) is an important process for nitrogen removal in marine pelagic and benthic environments and represents a major sink in the global nitrogen cycle. We applied a suite of complementary methods for the detection and enumeration of anammox activity and anammox bacteria in marine sediments of the Gullmar Fjord, and compared the results obtained with each technique. 15N labelling experiments showed that nitrogen removal through N(2) production was essentially limited to the upper 2 cm of the sediment, where anammox contributed 23-47% of the total production. The presence of marine anammox bacteria belonging to the genus 'Candidatus Scalindua' was shown by 16S rRNA gene sequence comparison. FISH counts of anammox bacteria correlated well with anammox activity, while quantitative PCR may have underestimated the number of anammox bacterial 16S rRNA gene copies at this site. Potential nitrogen conversion by anammox ranged from 0.6 to 4.8 fmol N cell-1 day-1, in agreement with previous measurements in the marine environment and in bioreactors. Finally, intact ladderane glycerophospholipid concentrations better reflected anammox activity and abundance than ladderane core lipid concentrations, most likely because the core lipid fraction contained a substantial fossil component, especially deeper in the sediment.
An assay to identify the common food-borne pathogens Salmonella, Escherichia coli, Shigella, and Listeria monocytogenes was developed in collaboration with Ibis Biosciences (a division of Abbott Molecular) for the Plex-ID biosensor system, a platform that uses electrospray ionization mass spectroscopy (ESI-MS) to detect the base composition of short PCR amplicons. The new food-borne pathogen (FBP) plate has been experimentally designed using four gene segments for a total of eight amplicon targets. Initial work built a DNA base count database that contains more than 140 Salmonella enterica, 139 E. coli, 11 Shigella, and 36 Listeria patterns and 18 other Enterobacteriaceae organisms. This assay was tested to determine the scope of the assay's ability to detect and differentiate the enteric pathogens and to improve the reference database associated with the assay. More than 800 bacterial isolates of S. enterica, E. coli, and Shigella species were analyzed. Overall, 100% of S. enterica, 99% of E. coli, and 73% of Shigella spp. were detected using this assay. The assay was also able to identify 30% of the S. enterica serovars to the serovar level. To further characterize the assay, spiked food matrices and food samples collected during regulatory field work were also studied. While analysis of preenrichment media was inconsistent, identification of S. enterica from selective enrichment media resulted in serovar-level identifications for 8 of 10 regulatory samples. The results of this study suggest that this high-throughput method may be useful in clinical and regulatory laboratories testing for these pathogens. PMID:23001674
Abstract in english The aim of this cross-sectional study was to examine the relationship between the composition of the subgingival microbiota and the vitamin D receptor (VDR) gene polymorphism in Brazilian adults with chronic periodontitis. The clinical parameters of probing depth, clinical attachment level, bleeding on probing, plaque accumulation and suppuration were measured in 60 Caucasian adults who were divided into two groups: 30 healthy individuals (control) and 30 with chronic per (more) iodontitis (ChP). Subgingival plaque samples were collected from 6 sites per subject and analyzed for 38 bacterial species using the Checkerboard DNA-DNA Hybridization. DNA was obtained from the subjects' epithelial cells by scraping the buccal mucosa and using a mouthwash containing 3% of glucose. Polymorphism in the VDR gene was analyzed by the polymerase chain reaction (PCR), followed by Taql digestion (RFLP). The healthy subjects presented significantly lower levels (0.3 × 10(7) ± 0.7 × 10(7)) of total microbial counts in comparison with subjects with chronic periodontitis (4.5 × 10(7) ± 2.9 × 10(7)). Regarding the occurrence of VDR polymorphism, it was observed that the Tt genotype was more prevalent in the Periodontitis group (60%) than in the Healthy group (30%), while the prevalences of the TT genotype were 23.3% and 53.3%, respectively (Chi-square test, p
OBJECTIVES/HYPOTHESIS: Microbial biofilms have been implicated in the pathogenesis of chronic rhinosinusitis with nasal polyposis (CRSwNP). Although biofilms are characterized by an extremely high resistance against chemical and physical agents, low-frequency ultrasound (LFU) treatment has been suspected to be an efficient and safe method for biofilm disruption. STUDY DESIGN: Basic science experimental study. METHODS: A total of 10 patients with CRSwNP undergoing endoscopic sinus surgery were analyzed. Two series of identical nasal polyps (n = 20) were processed to hematoxylin-eosin (HE) and Gram staining and to continuous-wave LFU treatment (5 minutes, 0.4 MHz, 37°C), respectively. RESULTS: Presence of microbial biofilms was confirmed in all patients with CRSwNP. HE staining showed a strong correlation with the results of Gram protocol in biofilm detection. In the LFU-treated group (n = 10), a significantly decreased inflammatory cell count was found in the subepithelial layer of nasal polyps (P < .001). In addition, bacterial biofilms were completely removed from the surface of the epithelial layer. Microscopic tissue injuries or significant temperature changes were not detected due to LFU treatment. CONCLUSIONS: Between in vitro conditions, LFU treatment appeared to be a reliable and microscopically safe method for the disruption of microbial biofilms in CRSwNP. These results may provide a basis for a prospective human study investigating the efficacy and safety of this therapeutic modality alone or in combination with antibiotics or topical steroids in biofilm-positive cases of CRSwNP. Laryngoscope, 2012. PMID:22893599
Prevalence of Salmonella and Vibrio spp. in seafood products sold in Singapore.
Foodborne hazards in seafood have only recently received increased attention in Singapore since the illness outbreak in 2009 that was associated with consumption of Indian rojak (a traditional salad of fruits, vegetables, and seafood). The microbiological quality of seafood must be evaluated for assurance of food safety. The aim of this study was to evaluate the microbiological quality and to determine the prevalence of Salmonella and Vibrio spp. in seafood sold in Singapore. A total of 116 samples (41 prawn, 44 shellfish, and 31 fishball samples) were collected from major supermarkets and wet markets in Singapore. The mesophilic and psychrotrophic bacterial counts for prawn, shellfish, and fishballs were 2 to 7 log CFU/g. One Salmonella Lexington strain was isolated from a thawed-frozen shellfish product and two Vibrio parahaemolyticus strains were isolated from commercial fishball and shrimp meat products. Thus, seafood sold in Singapore has the potential to be contaminated with Vibrio spp. and Salmonella, and proper handling at food service establishments is required to ensure food safety. Effective control measures also are needed to prevent cross-contamination during postharvest seafood processing. PMID:22980017
Aseptic colon resection by an invagination technique. Experimental study on dogs
A new aseptic colon resection by an invagination technique is presented. The bowel to be resected is invaginated down into the healthy intestine, and the anastomosis is sutured in one layer of continuous suture before transection by a diathermy wire, placed in the intestinal lumen via the anus. Sections of bowel that cannot be invaginated, e.g., because of a tumor, are first removed by transection between pairs of cable ties, which close the lumen. Twenty dogs were operated on without receiving prophylactic antibiotics. In 10, the intestine was transected between cable ties. An imprint, taken from the anastomosis and subcutis, was cultured. The bacterial count at the anastomosis exceeded 100 in only three cases; in the subcutis, this was the case in one dog. One wound infection developed. Serial barium enemas at 1, 2, 3, and 4 weeks revealed no anastomotic leakage. One early death because of a total anastomotic dehiscence was encountered, and two dogs were killed because of wound dehiscence and anastomotic stricture, respectively. It is concluded that, in dogs, the method is easily and safely performed, but further experimental studies are needed.
Water from Lake Anna in Virginia, a lake that is used to cool reactors at a nuclear power plant and for recreational activities, was assessed for the presence of Naegleria fowleri, an ameba that causes primary amebic meningoencephalitis (PAM). This survey was undertaken because it has been reported that thermally enriched water fosters the propagation of N. fowleri and, hence, increases the risk of infection to humans. Of 16 sites sampled during the summer of 2007, nine were found to be positive for N. fowleri by a nested polymerase chain reaction assay. However, total ameba counts, inclusive of N. fowleri, never exceeded 12/50 mL of lake water at any site. No correlation was obtained between the conductivity, dissolved oxygen, temperature, and pH of water and presence of N. fowleri. To date, cases of PAM have not been reported from this thermally enriched lake. It is postulated that predation by other protozoa and invertebrates, disturbance of the water surface from recreational boating activities, or the presence of bacterial or fungal toxins, maintain the number N. fowleri at a low level in Lake Anna. PMID:19043740
Use of phytogenic products as feed additives for swine and poultry.
This article summarizes the experimental knowledge on efficacy, possible modes of action, and aspects of application of phytogenic products as feed additives for swine and poultry. Phytogenic feed additives comprise a wide variety of herbs, spices, and products derived thereof, and are mainly essential oils. The assumption that phytogenic compounds might improve the palatability of feed has not yet been confirmed by choice-feeding studies. Although numerous studies have demonstrated antioxidative and antimicrobial efficacy in vitro, respective experimental in vivo evidence is still quite limited. The same applies to the supposition that phytogenic compounds may specifically enhance activities of digestive enzymes and nutrient absorption. Nevertheless, a limited number of experimental comparisons of phytogenic feed additives with antibiotics and organic acids have suggested similar effects on the gut, such as reduced bacterial colony counts, fewer fermentation products (including ammonia and biogenic amines), less activity of the gut-associated lymphatic system, and a greater prececal nutrient digestion, probably reflecting an overall improved gut equilibrium. In addition, some phytogenic compounds seem to promote intestinal mucus production. Such effects may explain a considerable number of practical studies with swine and poultry reporting improved production performance after providing phytogenic feed additives. In total, available evidence indicates that phytogenic feed additives may add to the set of nonantibiotic growth promoters for use in livestock, such as organic acids and probiotics. However, a systematic approach toward the efficacy and safety of phytogenic compounds used as feed additives for swine and poultry is still missing. PMID:18073277
Antibacterial copper-nickel bilayers and multilayer coatings by pulsed laser deposition on titanium.
Biofouling, especially microfouling, is a major concern with the use of titanium (Ti) in the marine environment as a condenser material in cooling water systems. Earlier, copper-nickel (Cu/Ni) alloys were extensively used in marine environments due to their high corrosion and biofouling resistance. However, the choice of condenser material for the new fast breeder reactor in Kalpakkam is Ti to avoid steam side corrosion problems, which may pose a threat to steam generator parts having sodium as the secondary coolant. This study evaluates the surface modification of Ti using nano films of copper (Cu) and nickel (Ni) to utilize the antibacterial property of copper ions in reducing microfouling. The surface modification of Ti was carried out by the deposition of a Cu/Ni bilayer and (Cu/Ni)(10) multilayer films using a pulsed laser deposition technique. Various surface characterization studies revealed that the deposited Cu/Ni films were thin and nanocrystalline in nature. The antibacterial properties were evaluated using total viable count and epifluorescence microscopic techniques. The results showed an apparent decrease in bacterial attachment on multilayered and bilayered Cu/Ni thin films on Ti surfaces. Comparative studies between the two types of films showed a bigger reduction in numbers of microorganisms on the multilayers. PMID:20183129
Combined sequential treatment using 100 mg/L sucrose monopalmitate solution under microbubble generation and soaking in slightly acidic hypochlorous water containing 30 mg/L available chlorine for 5 min at 50°C was tested for decontamination of ginger, Japanese ginger, perilla, parsley, Welsh onion and cucumber, and at 20°C for strawberry. Viable bacterial count was reduced by about 2 log cfu/g in perilla, parsley, and Welsh onion. Ginger, parsley and Welsh onion maintained viable counts of less than 5 log cfu/g during 6 days of subsequent cold storage at 6°C. Viable count for cucumber decreased by only 1 log cfu/g after combined treatment, and increased to 5.5 log cfu/g after storage for 6 days at 6°C. For decontamination of strawberry, as 50°C treatment with SAHW damaged the surface, the treatment was performed at 20°C. After combined sequential treatment, viable bacterial count decreased from 4.5 to 2.0 log cfu/g, and increased slightly to 2.5 log cfu/g after storage at 6°C for 6 days. Fungal count for strawberry also decreased from 4.9 to 2.3 log cfu/g immediately after treatment and did not increase after storage for 6 days. These results indicate the great potential of this approach in sanitization of fresh fruits and vegetables.
Hematological values of some Bothrops species (Ophidia - Crotalidae) in captivity
Abstract in english Blood samples of 50 healthy specimens from each of the following species: Bothrops alternatus, Bothrops jararacussu, Bothrops moojeni, and Bothrops neuwiedi diporus all kept in captivity were taken to determine the hematocrit (PCV) value, red blood cell count (RBC), total leukocyte (WBC) and differential leukocyte count, thrombocyte count, mean corpuscular volume (MCV), hemoglobin concentration (HbC), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin conc (more) entration (MCHC). These hematological parameters were compared to those obtained from other Bothrops species. PCV values, RBC, hemoglobin, WBC count, and differential leukocyte count are within the range of values reported for other Bothrops species, while the thrombocyte count was significantly lower. All the hematological parameters obtained from the four studied Bothrops species were higher than those described for B. ammodytoides.
The aim of this study was to investigate development over time of the surface expression of CD44 on macrophages during an inflammatory response of bovine mammary gland. Intramammary instillation of muramyl dipeptide (MDP) and lipopolysaccharide (LPS) resulted in a significant increase in the total count of CD44+ non-vacuolised macrophages (NMAC) after 24h. During resolution of the inflammatory response, there was observed a gradual decrease in the total count CD44+ NMAC. The lower total count and proportion of CD44+vacuolised macrophages (VMAC) was observed as the effect of MDP and LPS at 24h after induction (P<0.01). During resolution, the total count and proportion of CD44+VMAC increased. We have demonstrated CD44 receptor is expressed during the inflammatory response caused by LPS and M...
Microbial Changes on Full and Reduced Fat Edam Cheese during Maturation
The objective of this research was to determine the microflora of full fat and reduced fat Edam cheese during maturation. Reduced fat (16% fat) and full fat (28% fat) Edam cheese was stored up to 20 weeks at 6°C after manufacture. The cheeses were analyzed for pH, moisture, total solids, fat and protein content. Reduced fat cheese had higher protein and water content than full fat. We determined total bacteria, lactococci, and lactobacilli counts of reduced and full fat cheese during 5 months of ripening. Results revealed that total bacteria counts were about 1.9×105/g at one day for reduced fat cheese and 8×106/g for full fat cheese. Total counts decreased during maturation in both cheeses. Initial lactococcal counts were about the same in both products.
Splenic hypofunction in the nephrotic syndrome of childhood
The reticuloendothelial system, including the spleen, subserves important immunologic functions. Loss of splenic function results in an increased incidence of severe bacterial infections and is accompanied by thrombocytosis. Several nephrotic children were noted to have remarkably high platelet counts and predisposition to bacterial infection with encapsulated organisms. We, therefore, investigated the splenic function of nine children with primary nephrotic syndrome and measured the phagocytic function of the spleen by sequestration of Technetium-99-labelled heat-treated autologous RBC, administered intravenously. Four children had decreased splenic function. Repeat studies performed in two of these children after remission of the nephrotic syndrome gave normal results. There were six episodes of bacterial infection (3 peritonitis, 1 septic arthritis, 1 cellulitis, and 1 Escherichia coli urinary tract infection) among the four patients with decreased splenic function. There were no episodes of bacterial infection among the five nephrotic children with normal splenic function. Nephrotic patients with decreased splenic function had significantly increased platelet counts (921,000 +/- 196,000; mean +/- SEM) compared to those with normal function (435,000 +/- 46,000; P less than 0.001). Our findings suggest the possibility that some nephrotic children may have decreased splenic function in association with increased susceptibility to bacterial infections.
Wound infection development is critically dependent on the complex interactions between bacteria and host. Klebsiella pneumoniae has become an increasingly common wound pathogen, but its natural history within wounds has never been studied. Using a validated, in vivo rabbit ear model, wounds were inoculated with K.?pneumoniae at different concentrations (10²-10? colony-forming units) with measurement of viable and nonviable bacterial counts, histological wound-healing parameters, and host inflammatory gene expression at multiple time points postinoculation (48, 96, and 240 hours). Bacteria and wound morphologies were evaluated with scanning electron microscopy. Comparable experiments were performed in ischemic ears to model immune response impairment. All wounds, despite different inoculants, equilibrated to similar bacterial concentrations by 96 hours. With a 10? colony-forming units inoculant, wounds at 240 hours showed decreased bacterial counts (p?0.01), with a corresponding improvement in healing (p?0.01) and a decrease in inflammatory response (p?0.05). In contrast, ischemic wounds revealed impaired inflammatory gene expression (p?0.05) resulting in higher steady-state bacterial concentrations (p?0.01), impaired healing (p?0.05), and biofilm formation on scanning electron microscopy. We conclude that a normal inflammatory response can effectively stabilize and overcome a K.?pneumoniae wound infection. An impaired host cannot control this bacterial burden, preventing adequate healing while allowing bacteria to establish a chronic presence. Our novel study quantitatively validates the host immune response as integral to wound infection dynamics. PMID:22332606
Surgical Treatment of Neurologic Complications of Bacterial Meningitis in Children in Kosovo
Neurologic complications of bacterial meningitis can occur any time during the course of the disease and some of them need neurosurgical aproach. Objective: to determine the incidence of neurologic complications of bacterial meningitis in children requring neurosurgical treatment. Material and methodology: a total of 277 children were followed and treated for bacterial meningitis at the Clinic of Infectious Diseases in Prishtina. The authors have analyzed cases who developed acute neurologic complications and treatment procedures. Results: of the 277 children treated for bacterial meningitis, due to the suspicion for neurologic complications, 109 children underwent a head computerized tomography scan. About 47 cases (43%) had evident structural abnormalities while only 15/277 cases (5%) re...
Eukaryotic and prokaryotic microbial communities during microalgal biomass production
Eukaryotic and bacterial communities were characterized and quantified in microalgal photobioreactor cultures of freshwater Chlorella vulgaris and marine Dunaliella tertiolecta. The microalgae exhibited good growth, whilst both cultures contained diverse bacterial communities. Both cultures included Proteobacteria and Bacteroidetes, while C. vulgaris cultures also contained Actinobacteria. The bacterial genera present in the cultures were different due to different growth medium salinities and possibly different extracellular products. Bacterial community profiles were relatively stable in D. tertiolecta cultures but not in C. vulgaris cultures likely due to presence of ciliates (Colpoda sp.) in the latter. The presence of ciliates did not, however, cause decrease in total number of C. vul...
Mechanism of Mycobacterium avium subsp. paratuberculosis (Map) invasion through intestinal mucosa is not completely understood. In the present study, we developed an in vivo multiple-intestinal loop model in lambs to investigate (i) the type of cells involved in the bacterial uptake across the intestinal mucosa, (ii) the efficiency of bacterial uptake in different segments of the small intestine and (iii) the ability of different strains of Map to invade the various segments of the small intestine. Four loops on ileum and four loops each on Peyer's patch and non-Peyer's patch areas of jejunum were constructed by surgical procedure. The caprine, bovine, and vaccine strains of Map were used for infection. Map-infected intestinal loop tissues were collected at 1, 3, 6, 12, and 24h post-infection and processed for electron microscopy, histology, bacterial culture and bacterial counting. All these parameters revealed that Map invaded through M cells and the enterocytes and bacterial translocation across M cells was greater than the enterocytes. Bacterial invasion was greater in ileal loops when compared to jejunal loops. Within the jejunal loops, bacterial uptake was higher in Peyer's patch areas than that of non-Peyer's patch areas. The caprine and bovine strains of Map showed greater ability for invasion into the small intestinal mucosa than that of the vaccine strain. PMID:23122809
Nodal Counts on MDCT as a Surrogate Marker for Surgical Curability in Gastric Cancer
Background Thin-slice multidetector row computed tomography (MDCT) has emerged as a promising diagnostic modality in various cancers. This study was designed to evaluate the utility of metastatic nodal counts on MDCT as a surrogate maker for surgical curability in gastric cancer. Methods Between 2005 and 2007, a total of 92 patients with gastric cancer underwent preoperative MDCT at a slice thickness of 1.0?mm at our hospital. All regional lymph nodes showing metastatic involvement were preoperatively counted. Results Although the total counts of metastatic lymph nodes on MDCT were significantly smaller than those found by histopathology (P?=?0.00001), there was a significant correlation between nodal counts on MDCT and histopathology by Spearman?s analysis [P?x (counts on MDCT)?+?2.5]. No...
Our objective was to determine the suppressive abilities of bacterial metabolites derived from Xenorhabdus and Photorhabdus spp. on Glomerella cingulata, Phomopsis sp., Phytophthora cactorum, and Fusicladosporium effusum, which are fungal or oomycete pathogens of pecan, and Monilinia fructicola, a fungal pathogen of peach. In the first set of in vitro assays, when metabolites were compared based on initial bacterial cell count, X. bovienii (SN) metabolites generally exhibited the greatest suppression of phytopathogens and Xenorhabdus sp. (355) the least with Photorhabdus luminescens (Hb) and Xenorhabdus nematophila (All) being intermediate. In a second set of in vitro assays, in which metabolites were compared at 50 mg per ml acetone, P. luminescens (VS) exhibited greater suppression ...
Summary Background: Procalcitonin (PCT) is a specific biomarker for early detection of bacterial infections. While the usefulness of procalcitonin in severe conditions such as sepsis is well established, its relevance in the diagnosis and prognosis of localized cutaneous bacterial infections is unknown. Our aim was to initially evaluate if PCT is a useful parameter for predicting the severity of skin and skin structure infections (SSSI). Furthermore, the correlation of PCT levels with C-reactive protein (CRP), leukocyte counts, erythrocyte sedimentation rate (ESR), and body temperature was investigated. Patients and Methods: Serum PCT, routine laboratory parameters, and body temperature were regularly examined in 50 consecutive patients with SSSI requiring inpatient intravenous antibiotic ...
Purifying, Separating, and Concentrating Cells From a Sample Low in Biomass
Frequently there is an inability to process and analyze samples of low biomass due to limiting amounts of relevant biomaterial in the sample. Furthermore, molecular biological protocols geared towards increasing the density of recovered cells and biomolecules of interest, by their very nature, also concentrate unwanted inhibitory humic acids and other particulates that have an adversarial effect on downstream analysis. A novel and robust fluorescence-activated cell-sorting (FACS)-based technology has been developed for purifying (removing cells from sampling matrices), separating (based on size, density, morphology), and concentrating cells (spores, prokaryotic, eukaryotic) from a sample low in biomass. The technology capitalizes on fluorescent cell-sorting technologies to purify and concentrate bacterial cells from a low-biomass, high-volume sample. Over the past decade, cell-sorting detection systems have undergone enhancements and increased sensitivity, making bacterial cell sorting a feasible concept. Although there are many unknown limitations with regard to the applicability of this technology to environmental samples (smaller cells, few cells, mixed populations), dogmatic principles support the theoretical effectiveness of this technique upon thorough testing and proper optimization. Furthermore, the pilot study from which this report is based proved effective and demonstrated this technology capable of sorting and concentrating bacterial endospore and bacterial cells of varying size and morphology. Two commercial off-the-shelf bacterial counting kits were used to optimize a bacterial stain/dye FACS protocol. A LIVE/DEAD BacLight Viability and Counting Kit was used to distinguish between the live and dead cells. A Bacterial Counting Kit comprising SYTO BC (mixture of SYTO dyes) was employed as a broad-spectrum bacterial counting agent. Optimization using epifluorescence microscopy was performed with these two dye/stains. This refined protocol was further validated using varying ratios and mixtures of cells to ensure homogenous staining compared to that of individual cells, and were utilized for flow analyzer and FACS labeling. This technology focuses on the purification and concentration of cells from low-biomass spacecraft assembly facility samples. Currently, purification and concentration of low-biomass samples plague planetary protection downstream analyses. Having a capability to use flow cytometry to concentrate cells out of low-biomass, high-volume spacecraft/ facility sample extracts will be of extreme benefit to the fields of planetary protection and astrobiology. Successful research and development of this novel methodology will significantly increase the knowledge base for designing more effective cleaning protocols, and ultimately lead to a more empirical and true account of the microbial diversity present on spacecraft surfaces. Refined cleaning and an enhanced ability to resolve microbial diversity may decrease the overall cost of spacecraft assembly and/or provide a means to begin to assess challenging planetary protection missions.
Background Although bacterial biofilm is recognized as an important contributor to chronic wound pathogenesis, differences in biofilm virulence between species have never been studied in vivo. Study Design Dermal punch wounds in New Zealand white rabbit ears were inoculated with Klebsiella pneumoniae, Staphylococcus aureus, or Pseudomonas aeruginosa, or left uninfected as controls. In vivo biofilm was established and maintained using procedures from our previously published wound biofilm model. Virulence was assessed by measurement of histologic wound healing and host inflammatory mediators. Scanning electron microscopy (SEM) and bacterial counts verified biofilm viability. Extracellular polymeric substance (EPS)-deficient P aeruginosa was used for comparison. Results SEM confirmed the pre...
Background- Bacterial contamination of platelet concentrates (PCs) still remains a significant problem in transfusion with potential important clinical consequences, including death. The International Society of Blood Transfusion Working Party on Transfusion-Transmitted Infectious Diseases, Subgroup on Bacteria, organised an international study on Transfusion-Relevant Bacteria References to be used as a tool for development, validation and comparison of both bacterial screening and pathogen reduction methods. Material and Methods- Four Bacteria References (Staphylococcus epidermidis PEI-B-06, Streptococcus pyogenes PEI-B-20, Klebsiella pneumoniae PEI-B-08 and Escherichia coli PEI-B-19) were selected regarding their ability to proliferate to high counts in PCs and distributed anonymised to ...
The diagnostic performance of procalcitonin and neopterin as markers for bacterial and viral causes of fever was evaluated in a cohort of 69 febrile travellers with known etiological agents. Our aim was to establish a decision rule to minimize empirical antibiotic treatment. Compared with C-reactive protein (CRP) and leukocyte (differential) counts, procalcitonin and neopterin had a disappointing diagnostic accuracy. Refraining from antibiotics in case of combined presence of lymphocytosis and/or CRP ?10 mg/l would result in an 85% reduction in unwanted antibiotic treatment in patients with viral disease but in adequate antibiotic coverage of all patients with bacterial disease. PMID:22357400
The diagnostic performance of procalcitonin and neopterin as markers for bacterial and viral causes of fever was evaluated in a cohort of 69 febrile travellers with known etiological agents. Our aim was to establish a decision rule to minimize empirical antibiotic treatment. Compared with C-reactive protein (CRP) and leukocyte (differential) counts, procalcitonin and neopterin had a disappointing diagnostic accuracy. Refraining from antibiotics in case of combined presence of lymphocytosis and/or CRP @?10mg/l would result in an 85% reduction in unwanted antibiotic treatment in patients with viral disease but in adequate antibiotic coverage of all patients with bacterial disease.
Moxifloxacin is a respiratory quinolone that is expected to be useful for treating community-acquired bacterial pneumonia, but few clinical studies and not a detailed evaluation of its pharmacokinetics have been conducted in Japan in patients with pneumonia. We assessed the efficacy and safety of moxifloxacin in 18 patients with community-acquired bacterial pneumonia using pharmacokineticâ??????pharmacodynamic analysis. There was significant improvement in body temperature, white blood cell count, C-reactive protein, and chest X-ray score on day 3 of moxifloxacin treatment, which persisted until the completion of treatment (all p?? Streptococcus pneumoniae, Moraxella catarrhalis, Haemophilus influenzae, and Enterobacter cloacae, were isolated from sputum cultures of nine patients. The is...
Chlorination is a common antifouling method adopted by industrial units to minimize the fouling growth on cooling systems. In the present study, the effect of sodium hypochlorite on extracellular polymeric substance (EPS) production, hydrophobicity, cell adhesion and viability of marine bacteria involved in biofilm formation were assessed in laboratory condition. Two bacterial strains, tentatively identified as Alteromonas sp. and Pseudomonas sp. isolated from the surface of seaweeds were used as test organisms for the present study. The bacterial cultures were treated with sodium hypochlorite at 25% of the minimum inhibitory concentration. Results showed considerable variation in the production of EPS, viable counts, hydrophobicity and adhesion ability of bacteria treated with sodium hypo...
A model system for evaluating surface disinfection in dairy factory environments
A model system was developed for evaluating the efficacy of disinfectants for inactivating bacteria present in biofilms on surfaces within dairy factory environments. Mixed culture biofilms of six dairy factory isolates (pseudomonads, coliforms and presumptive staphylococci) were generated on factory floor tiles and subjected to up to three fouling and cleaning (FC) cycles. Disinfectants (hypochlorite, peroxyacetic acid-, acid anionic- and quaternary ammonium compound (QUAT)-based products) were applied after cleaning at the supplier's recommended concentrations. Bacterial groups were enumerated using selective agar media. All disinfectants significantly (p<0.05) reduced surface counts of the three bacterial groups. The peroxyacetic acid-based product applied at 3.0% (v/v) achieved the gre...
Abstract in english Hydrogen peroxide and chlorine are compared as possible disinfectants for water-cooling circuits. To this purpose, samples taken from the cooling system of a steel making plant were treated (at 25ºC and pH values of 5.5 and 8.5) with varying amounts of the two oxidizing agents (0.0 mg/L, 2.0 mg/L and 6.0 mg/L). The results were evaluated through bacterial counting and measurement of corrosion rates upon AISI1020 carbon steel coupons. Bacterial removal and corrosion effects proved to be similar and satisfactory for both reagents.
Does the h-index have predictive power?
Bibliometric measures of individual scientific achievement are of particular interest if they can be used to predict future achievement. Here we report results of an empirical study of the predictive power of the h-index compared to other indicators. Our findings indicate that the h-index is better than other indicators considered (total citation count, citations per paper, and total paper count) in predicting future scientific achievement. We discuss reasons for the superiority of the h-index.
The testis is an immunologically privileged organ. Sertoli cells can form a blood-testis barrier and protect sperm cells from self-immune system attacks. Spermatogenesis may be inhibited by severe illness, bacterial infections and chronic inflammatory diseases but the mechanism(s) is poorly understood. Our objective is to help in understanding such mechanism(s) to develop protective agents against temporary or permanent testicular dysfunction. Lipopolysaccaride (LPS) is used as a model of animal sepsis while L-carnitine (LCR) is used as a protective agent. A total of 60 male Swiss albino rats were divided into four groups (15/group). The control group received Saline; the 2(nd) group was given LCR (500 mg/kg i.p, once). The third group was treated with LPS (5 mg/kg i.p once) and the fourth group received LCR then LPS after three hours. From each group, five rats were used for histopathological examination. Biochemical parameters were assessed in the remaining ten rats. At the end of the experiment, animals were lightly anaesthetized with ether where blood samples were collected and testes were dissected on ice. Sperm count and motility were evaluated from cauda epididymis in each animal. Also, oxidative stress was evaluated by measuring testicular contents of reduced glutathione (GSH), malondialdehyde (MDA) and 8-hydroxydeoxyguanosine (8-HDG, the DNA adduct for oxidative damage) in testicular DNA. The pro-inflammatory mediator nitric oxide (NO) in addition to lactate dehydrogenase (LDHx) isoenzyme-x activity as an indicator for normal spermatozoal metabolism were assessed in testicular homogenate. Serum interlukin (IL)-2 level was also assessed as a marker for T-helper cell function. The obtained data revealed that LPS induced marked reductions in sperm's count and motility, obstruction in seminiferous tubules, hypospermia and dilated congested blood vessels in testicular sections concomitant with decreased testicular GSH content and LDHx activity. Moreover, the testicular levels of MDA, 8-HDG (in testicular DNA) and NO as well as serum IL-2 level were increased. Administration of LCR before LPS returned both sperm count and motility to normal levels. Also, contents of testicular GSH, MDA, 8-HDG and NO returned back to the corresponding control values. In addition, serum IL-2 level as well as histological abnormalities were markedly improved in LCR + LPS-treated rats. In conclusion, LPS increased proinflammatory and oxidative stress markers in the testis leading to a marked testicular dysfunction. L-carnitine administration ameliorates these effects by antioxidant and/or anti-inflammatory mechanisms suggesting a protective role against male infertility in severely infected or septic patients. PMID:20357928
The bivalve Ruditapes decussatus was evaluated as a possible biomonitor of heavy-metal contamination. Concentrations of copper (Cu), cobalt (Co), iron (Fe), nickel (Ni), and manganese (Mn) were measured in R. decussatus. Water and sediment samples were collected at two stations of Timsah Lake in Ismailia, Egypt, from October to November 2002, using atomic absorption spectrophotometry (AAS). Results from the heavy-metal and microbial analyses indicated that site II was less contaminated than site I. The bivalve showed accumulation of metals, with a bioaccumulation factor (BAF) greater than 4. The bioaccumulation of metals varied strongly according to the sampling site. After 48 h of depuration, Fe, Ni, Co, Cu, and Mn were reduced significantly, to 46.8% and 47.7%, 19.9% and 20.3%, 27.3% and 27.9%, 35.9% and 36.6%, and 18.2% and 26.6%, compared with the initial concentrations, in clam tissue at the two stations. In bivalves from site II the counts of total bacteria, fecal coliforms, and bacterial pathogens were reduced by more than 90%, whereas phage counts were only reduced by 56% after 4 days of depuration. The depuration of bivalves collected from the heavily polluted site (I) was not effective, as coliforms were reduced only by 85% after 4 days, whereas counts of pathogens and pathogenic indicators such as Vibrio, fecal Streptococcus, and coliphage decreased to less than 50% of the initial concentration. The time necessary to decrease contamination to 10%, 50%, and 90% for clams at both stations was consistently shorter for heavy metals than for microorganisms. Investigation of the effects of heavy-metal and microbiological depuration on valve movement and physiological rates (oxygen consumption and ammonia excretion) was carried out on R. decussatus to test the utility of physiological stress indices in assessing the health of depurated animals. Clams in the experimental tanks exhibited various states of activity, which were rated by identifying and scoring (0-4) the different parameters, including shell gap, siphon extension, and foot protrusion. Moreover, an increase in ammonia excretion was usually associated with an increase in respiration rate. The oxygen-to-nitrogen ratio provided a sensitive indicator of bivalve health. It can be concluded that shellfish monitoring and depuration data depended on the initial concentration of the pollutants. There were differences in the physiological responses of clams from the two sites during the periods of pre- and postdepuration of the contaminants. There was a significant correlation between reduction of metal concentration in clam tissue and enhancement of valve movement, as well as activity and increasing respiration rate. PMID:15038001
Abstract in portuguese OBJETIVOS: Avaliar a qualidade microbiológica de leite pasteurizado comercializado, isolar e identificar sorologicamente cepas de Escherichia coli enteropatogênica clássica (EPEC) nesse alimento. MÉTODOS: Foram estudadas 90 amostras de leite pasteurizado, de três marcas comerciais diferentes, dos tipos B e C, obtidas em padarias e supermercados do Rio de Janeiro, RJ. A contagem de coliformes totais e fecais foi estimada aplicando-se a técnica do número mais prováv (more) el. A quantificação de microorganismos mesófilos, psicrotróficos e termodúricos foi determinada pela técnica da contagem padrão em placa. A identificação fisiológica de E. coli foi realizada por metodologia convencional e a identificação sorológica de EPEC, com a utilização de soros comerciais. RESULTADOS: As três marcas de leite pasteurizado apresentaram contagens bacterianas acima do padrão permitido pela legislação brasileira. Foram isoladas 208 cepas de E. coli, entre as quais 46 (22,1%) foram sorogrupadas como EPEC. O sorogrupo mais freqüente foi o O55 (15,2%). CONCLUSÕES: Apesar de estudos recentes sobre fatores de virulência indicarem que nem todas as cepas sorogrupadas como EPEC são capazes de causar a lesão A/E (attaching/ effacing), considerou-se que o isolamento de sorogrupos de EPEC, nesse alimento, representa risco potencial para crianças e, também, possível meio de veiculação de outros enteropatógenos. Abstract in english OBJECTIVE: To evaluate the microbiological quality of pasteurized milk commercialized in Rio de Janeiro, Brazil, and determine serologically enteropathogenic Escherichia coli (EPEC) strains in E. coli isolates obtained from milk samples. METHODS: Ninety samples of pasteurized milk -- types B and C -- of three different commercial brands, purchased in supermarkets and bakeries in Rio de Janeiro, were examined. The amount of total and fecal coliform bacteria was estimated u (more) sing the Most Probable Number technique. Mesophilic, psychrotrophic, and thermoduric microorganism counts were determined by the Standard Plate Count technique. Isolation and identification of E. coli were carried out using conventional physiological tests. Commercial antisera were used for serological characterization of EPEC. RESULTS: The three milk brands analyzed revealed bacterial counts above the regulated values of the Brazilian government. It was found that among 208 strains of E. coli isolated, 46 (22.1%) were serologically classified as EPEC. The most common EPEC serogroup was O55 (15.2%). CONCLUSIONS: Though recent studies on virulence factors indicate that not all strains serologically classified as EPEC are able to attaching/effacing lesion, it is believed that the isolation of EPEC serogroups from pasteurized milk represent a potential risk for children, as well as an indicative of the presence of other enteropathogens.
Multiple Loci Are Associated with White Blood Cell Phenotypes
White blood cell (WBC) count is a common clinical measure from complete blood count assays, and it varies widely among healthy individuals. Total WBC count and its constituent subtypes have been shown to be moderately heritable, with the heritability estimates varying across cell types. We studied 19,509 subjects from seven cohorts in a discovery analysis, and 11,823 subjects from ten cohorts for replication analyses, to determine genetic factors influencing variability within the normal hematological range for total WBC count and five WBC subtype measures. Cohort specific data was supplied by the CHARGE, HeamGen, and INGI consortia, as well as independent collaborative studies. We identified and replicated ten associations with total WBC count and five WBC subtypes at seven different genomic loci (total WBC count—6p21 in the HLA region, 17q21 near ORMDL3, and CSF3; neutrophil count—17q21; basophil count- 3p21 near RPN1 and C3orf27; lymphocyte count—6p21, 19p13 at EPS15L1; monocyte count—2q31 at ITGA4, 3q21, 8q24 an intergenic region, 9q31 near EDG2), including three previously reported associations and seven novel associations. To investigate functional relationships among variants contributing to variability in the six WBC traits, we utilized gene expression- and pathways-based analyses. We implemented gene-clustering algorithms to evaluate functional connectivity among implicated loci and showed functional relationships across cell types. Gene expression data from whole blood was utilized to show that significant biological consequences can be extracted from our genome-wide analyses, with effect estimates for significant loci from the meta-analyses being highly corellated with the proximal gene expression. In addition, collaborative efforts between the groups contributing to this study and related studies conducted by the COGENT and RIKEN groups allowed for the examination of effect homogeneity for genome-wide significant associations across populations of diverse ancestral backgrounds.
The fate of indicator bacteria, a bacterial pathogen, and total aerobic bacteria during aerobic and anaerobic digestion of wastewater sludge under laboratory conditions was determined. Correlation coefficients were calculated between physical and chemical parameters (temperature, dissolved oxygen, p...
Entamoeba histolytica trophozoites produce amoebapores, a family of small amphipathic peptides capable of insertion into bacterial or eukaryotic membranes and causing cellular lysis. Recently, E. histolytica trophozoites that are totally deficient in the production of amoebapore-A were created throu...
Application of neutron multiplicity counting to waste assay
This paper describes the use of a new figure of merit code that calculates both bias and precision for coincidence and multiplicity counting, and determines the optimum regions for each in waste assay applications. A tunable multiplicity approach is developed that uses a combination of coincidence and multiplicity counting to minimize the total assay error. An example is shown where multiplicity analysis is used to solve for mass, alpha, and multiplication and tunable multiplicity is shown to work well. The approach provides a method for selecting coincidence, multiplicity, or tunable multiplicity counting to give the best assay with the lowest total error over a broad spectrum of assay conditions.
Eukaryotic and prokaryotic microbial communities during microalgal biomass production.
Eukaryotic and bacterial communities were characterized and quantified in microalgal photobioreactor cultures of freshwater Chlorella vulgaris and marine Dunaliella tertiolecta. The microalgae exhibited good growth, whilst both cultures contained diverse bacterial communities. Both cultures included Proteobacteria and Bacteroidetes, while C. vulgaris cultures also contained Actinobacteria. The bacterial genera present in the cultures were different due to different growth medium salinities and possibly different extracellular products. Bacterial community profiles were relatively stable in D. tertiolecta cultures but not in C. vulgaris cultures likely due to presence of ciliates (Colpoda sp.) in the latter. The presence of ciliates did not, however, cause decrease in total number of C. vulgaris or bacteria during 14days of cultivation. Quantitative PCR (qPCR) reliably showed relative microalgal and bacterial cell numbers in the batch cultures with stable microbial communities, but was not effective when bacterial communities varied. Raw culture samples were successfully used as qPCR templates. PMID:22995170
Biodegradation of a Bioemulsificant Exopolysaccharide (EPS2003) by Marine Bacteria
The aim of the study is to analyze the biodegradation capacity of a biosurfactant exopolysaccharide (EPS2003) by heterotrophic marine bacterial strains. During the initial screening performed in two sites located at the harbor of Messina for analyzing the response of marine bacterial population with the presence of biosurfactant EPS2003, ten bacterial strains capable to degrade this substance were isolated. Between the bacterial strains isolated, two representative bacterial strains, isoDES-01, clustered with Pseudoalteromonas sp. A28 (100%), and isoDES-07, closely related to Vibrio proteolyticus (98.9%), were chosen for mineralization and respirometry test, performed to evaluate biodegradability potential of EPS2003. Assays of bacterial growth and measure of concentration of total RNA wer...
A survey of ethnic foods for microbial quality and aflatoxin content.
A range of ethnic foods was examined for their microbiological content in relation to total viable counts (TVC) of aerobic bacteria, counts of presumptive coliforms, yeast and mould counts; presence of Salmonella spp., Listeria monocytogenes, Escherichia coli O157:H7 and Campylobacter spp.; total enumeration of Clostridium perfringens, Staphylococcus aureus and Bacillus spp.; identification of moulds and the presence of total aflatoxins. Samples, which included cereals, nuts, dried fruits, herbs and spices, were obtained from local retail outlets and distributors. It was established that three samples of pistachio nuts contained significant levels of aflatoxins. The concentration of total aflatoxins in these three nut samples ranged from 15 to 259 microg/kg of sample. Only two other samples contained trace amounts of aflatoxins, all other samples analysed were found to be free of any detectable level of aflatoxins. TVCs, coliform counts and yeast and mould counts varied widely depending on the matrix tested. Generally, rice, wheat and peanuts produced low counts whereas other nuts, gram flour and spices produced much higher counts. Cl. perfringens, Staph. aureus, and Bacillus spp. were common in spices, nuts and gram flour, however, Listeria monocytogenes was only detected in four samples and in no sample could Salmonella spp, E. coli O157:H7 or Campylobacter spp. be detected. PMID:11288910
Seasonal variability in airborne bacterial communities at a high-elevation site
Although bacteria are ubiquitous in the near-surface atmosphere, the temporal dynamics of airborne bacterial communities have not been well-studied. We examined seasonal shifts in bacterial abundances, the relative contribution of bacteria to total aerosol loads, and bacterial community structure at a high-elevation research station in northern Colorado, USA. Aerosol samples were collected from the near-surface atmosphere over 5-10 days during each of the four calendar seasons. Bacterial abundances varied by season with the highest concentrations observed during the fall and spring seasons, consistent with the changes in total particle concentrations, with bacterial cells often representing a large fraction (22% on average) of the total near-surface aerosol particles >0.5 ?m. Bacterial community composition, determined via barcoded pyrosequencing, also varied significantly by season. The dominant taxa in the spring, winter, and second half of the fall sampling periods (when the ground was snow covered) were bacterial taxa commonly found in other cold environments while the summer and first half of the fall samples contained taxa that were likely derived from soil and leaf-surface environments. Bacteria are clearly an important component of atmospheric aerosols with the abundance and composition of these airborne bacterial communities shaped by seasonal shifts in atmospheric conditions and the conditions of the local terrestrial environment.
Microbially enhanced compost extracts ('compost tea') are being used in commercial agriculture as a source of nutrients and for their perceived benefit to soil microbiology, including plant disease suppression. Rumen content material is a waste of cattle abattoirs, which can be value-added by conversion to compost and 'compost tea'. A system for compost extraction and microbial enhancement was characterised. Molasses amendment increased bacterial count 10-fold, while amendment based on molasses and 'fish and kelp hydrolysate' increased fungal count 10-fold. Compost extract incubated at 1:10 (w/v) dilution showed the highest microbial load, activity and humic/fulvic acid content compared to other dilutions. Aeration increased the extraction efficiency of soluble metabolites, and microbial growth rate, as did extraction of compost without the use of a constraining bag. A protocol of 1:10 dilution and aerated incubation with kelp and molasses amendments is recommended to optimise microbial load and fungal-to-bacterial ratio for this inoculum source. PMID:21752637
Evaluation of potential biomarkers for the discrimination of bacterial and viral infections
Purpose Timely knowledge of the bacterial etiology and localization of infection are important for empirical antibiotic therapy. Thus, the goal of this study was to evaluate routinely used biomarkers together with novel laboratory parameters in the diagnosis of infection. Methods In this prospective study, 54 adult patients with bacterial infections admitted to the Department of Infectious Diseases were included. For comparison, 27 patients with viral infections were enrolled. In these patients, white blood cell (WBC) counts, differential blood counts, serum levels of procalcitonin (PCT), IL-1?, IL-6, IL-8, IL-10, IL-12, TNF-?, IFN-?, soluble CD14 (sCD14), heparin-binding protein (HBP), cortisol (Cort), and monocyte surface expression of TLR2, TLR4, HLA-DR, and CD14 were analyzed. Also, th...
This work was aimed at isolating and identifying the microbiota present during the semi-dry method of coffee processing using polyphasic methods and to evaluate microbial diversity with PCR-DGGE. Samples of Coffea arabica L. were collected during different processing stages in southern Minas Gerais, Brazil. The bacterial and fungal isolates were phenotypically characterised and grouped according to the ARDRA technique, in which the 16-23S and ITS1-5.8S regions of the rDNA were sequenced for species identification. The bacterial counts varied from 3.7 to 7 log CFU g-1. The yeast counts ranged from 3.4 to 6.9 log CFU g-1, and the filamentous fungal population varied from 2 to 3.7 log CFU g-1. Bacillus subtilis, Escherichia coli, Enterobacter agglomerans, Bacillus cereus and Klebsiella pneumo...
Aeromonas salmonicida infected fish transfer disease to healthy fish via water
Experimental studies of infection transmission via water from infected to healthy fish were conducted. The dark-brown bacterial colonies typical for Aeromonas salmonicida on tryptone soya agar (TSA) have been isolated and counted (from 3.0?0.6?102 to 3.5?0.5?105 c.f.u. g?1) from the internal organs of naturally infected (NI) and experimentally infected (EI) perch and sea trout. No significant differences in dark-brown bacterial counts were detected between EI perch and EI sea trout. The assessment and comparison of the alterations of the biological parameters of EI European perch and sea trout with bacterium Aeromonas salmonicida subsp. salmonicida with naturally infected perch were conducted. No mortality was recorded in groups of EI perch and sea trout. Whereas, the mortality of NI perch...
Malaria is the most important parasitic disease, leading to annual death of about one million people, and the Plasmodium falciparum develops resistance to well-established antimalarial drugs. The newest antiplasmodial drug from a marine microorganism helps in addressing this problem. In the present study, Haliclona Grant were collected and subjected for enumeration and isolation of associated bacteria. The count of bacterial isolates was maximum in November 2007 (18???104?colony-forming units (CFU)?g?1, and the average count was maximum during the monsoon season (117???103?CFU?g?1). Thirty-three morphologically different bacterial isolates were isolated from Haliclona Grant, and the extracellular ethyl acetate extracts were screened for antiplasmodial activity against P. falciparum. The an...
Inhibitory effects of titanium(III) citrate on enumeration of bacteria from rumen contents
Titanium citrate (TC) or L-cysteine-sodium sulfide was added as a reducing agent to buffers and agar media used for enumeration of bacteria from rumen contents of high-forage-fed steers. Approximately equal colony counts were found on TC and L-cysteine-sodium sulfide-reduced media with rumen contents taken 8 h postfeeding, when active bacterial growth was occurring. The colony counts on TC medium were only 56% of those with L-cysteine-sodium sulfide medium with rumen contents taken 1 h prefeeding when bacterial growth was minimal. When colonies from L-cysteine-sodium sulfide medium were transferred to TC medium and vice versa, almost all colonies grew. The data indicate that TC can be inhibitory to bacteria upon their initial isolation from natural habitats, particularly when growth rates are low in these habitats.
Morphological changes in the intestine of dogs experimentally infected with Trichuris vulpis
A blinded randomized study was conducted on 24 cats to confirm the presence of bacterial and/or fungal secondary infections associated with otoacariasis and to verify the efficacy of Oridermyl, an acaricidal/antibiotic/antifungal/anti-inflammatory ointment, for treatment of the primary infestation and secondary infections. Sixteen cats were treated once daily for 10 d; 4 cats were not treated and 4 were treated with a placebo ointment. On Days 0 and 10, ears were swabbed for counts of bacteria and yeasts, for bacterial culture and sensitivity, and examined for determination of the degree of clinical otitis. Auricular secretions were removed for mite counts on Day 10, except for 8 treated cats that were done on Day 30. There was a high number of bacteria and yeasts in most cats and Oridermyl treatment significantly decreased those numbers. Staphylococci were the most frequently isolated bacteria. No live ear mites were found in cats treated with Oridermyl or the placebo ointment. PMID:12928886
Application of ATP bioluminescence for evaluation of surface cleanliness of milking equipment.
The ATP bioluminescence method was used to evaluate the cleanliness of milking equipment surfaces (teat cup rubbers, teat dip containers, milk receivers, and pipeline joints) in dairy farms in Galicia (northwest Spain) with parlour, pipeline tie-stall or bucket tie-stall milking systems. The cleanest surfaces were teat cup rubbers. The use of non-chlorinated water for cleaning, and of pipeline or bucket tie-stall milking systems, was associated with high ATP bioluminescence values. However, ATP bioluminescence values only explained 12% of the variability in bulk-tank bacterial count; this is attributable to the importance of other factors (notably the correct functioning of the tank cooling system) for maintenance of low bacterial count. PMID:18547666
Information on factors limiting the shelf life of extended shelf life (ESL) milk produced by microfiltration and subsequent pasteurization is very limited. In this study, three different batches of ESL milk were analyzed at different stages of the production process and during storage at 4^oC, 8^oC and 10^oC in order to evaluate the changes in bacterial cell counts, microbial diversity and enzymatic quality. Additionally, detailed biodiversity analyses of 250 retail ESL milk packages produced by five manufacturers in Germany, Austria and Switzerland were performed at the end of shelf life. It was observed that microfiltration decreased the microbial loads by 5-6 log10 units to lower than 1CFU/mL. However, bacterial counts at the end of shelf life were extremely variable and ranged between ...
We examined the effectiveness of a continuous tube-flow type UV irradiation system developed for cold pasteurization of solid particulate foods in flowing air. Among the six kinds of solid particulate foods tested, black pepper, red pepper, and oolong tea leaves could not be sterilized, since these were contaminated with bacterial spores which accounted for almost all counts of detectable bacteria. An apparently marked inactivation effect was obtained with green laver contaminated with relatively high counts of nonsporing bacteria. The effect of the irradiation system on green laver depended upon the flow rate of air supply and the irradiation time within the first 4 s. This system is not effective for killing bacterial spores but can be applied to kill vegetative cells. (author)
Hygienic-microbiological quality of tattoo- and permanent make-up colours
In a broad market survey, 145 samples of tattoo- and permanent make-up pigments were bacteriologically analysed. The pigments originated from 39 unopened vials and 106 opened vials in use. The samples were collected from 33 tattoo shops and 22 beauty studios and the analyses were effected by direct plating on four agar media and by enrichment in a non-selective broth. None of the used media could detect all contaminated samples. The best performance was obtained with sheep blood agar (BA), which detected bacterial counts in 7 of 39 (17.9?%) of unopened vials and in 22 of 106 (20.8?%) opened vials. In 12 of 145 samples (8.3?%), bacterial growth was observed in the enrichment broth but not on sheep BA. In most cases, contaminations were in a low range of 101?102?cfu?/?mL. Counts in the range...
SummaryThis study assessed the efficacy of a `dry' hydrogen peroxide vapour decontamination in an Australian hospital via a two-armed study. The in vivo arm examined the baseline bacterial counts in high-touch zones within wards and evaluated the efficacy of cleaning with a neutral detergent followed by either hydrogen peroxide vapour decontamination, or a manual terminal clean with bleach or Det-Sol 500. The in vitro arm examined the efficacy of hydrogen peroxide vapour decontamination on a variety of different surfaces commonly found in the wards of an Australian hospital, deliberately seeded with a known concentration of vancomycin-resistant enterococci (VRE). All bacterial counts were evaluated by a protocol of contact plate method. In the in vivo arm, 33.3% of the high-touch areas ass...
Malaria is the most important parasitic disease, leading to annual death of about one million people, and the Plasmodium falciparum develops resistance to well-established antimalarial drugs. The newest antiplasmodial drug from a marine microorganism helps in addressing this problem. In the present study, Haliclona Grant were collected and subjected for enumeration and isolation of associated bacteria. The count of bacterial isolates was maximum in November 2007 (18?×?104 colony-forming units (CFU)?g?1, and the average count was maximum during the monsoon season (117?×?103 CFU g?1). Thirty-three morphologically different bacterial isolates were isolated from Haliclona Grant, and the extracellular ethyl acetate extracts were screened for antiplasmodial activity against P. falciparum. The an...
The purpose of this study is to develop a pelagic ecosystem model considering microbial processes coupled with the non-hydrostatic flow field in estuaries and coasts. The model was applied to the ecosystem simulation in Ise Bay and was evaluated its reproducibility for field observational data. Calculation results also revealed that the bacterial production corresponded to 18.2 % of the primary production though the bacterial biomass accounted for only 3.9 % of the total. Additionally, the bacterial respiration corresponded to 50 % of the total oxygen consumption in the bottom layer.
Shellfish and shellfish-raising waters from a variety of Long Island and New Jersey marine embayments were examined for the presence of human enteroviruses. Little difference in virological quality was noted between areas designated as being open or closed to shellfishing. Viral isolations could not be correlated with coliform counts from identical samples, indicating the need to re-evaluate the use of bacterial standards as indices of the overall sanitary quality of water and shellfish.
The bibliography contains citations concerning the use of marine plants and animals as indicators of organic and inorganic pollutant distribution. Topics include descriptions of specific species and assemblages, regional and local monitoring studies, and analyses of the soft and hard parts of marine animals. Studies of algae, bivalves, corals, crustaceans, bacterial counts, and seagrasses in estuaries and benthic areas are included. (Contains 250 citations and includes a subject term index and title list.)
Bioindicators of marine pollution. (Latest citations from Oceanic Abstracts). Published Search
The bibliography contains citations concerning the use of marine plants and animals as indicators of organic and inorganic pollutant distribution. Topics include descriptions of specific species and assemblages, regional and local monitoring studies, and analyses of the soft and hard parts of marine animals. Studies of algae, bivalves, corals, crustaceans, bacterial counts, and seagrasses in estuaries and benthic areas are included. (Contains 250 citations and includes a subject term index and title list.)
This bibliography contains citations concerning the utilization of marine plants and animals as indicators of organic and inorganic pollutant distribution. Topics include descriptions of specific species and assemblages, regional and local monitoring studies, and analyses of the soft and hard parts of marine animals. Studies of algae, bivalves, corals, crustaceans, bacterial counts, and seagrasses in estuaries and benthic areas are included. (This updated bibliography contains 296 citations, 40 of which are new entries to the previous edition.)
Association of CFU-Mk with total colony-forming units in thawed cord blood units
Background and Objectives- Cord blood unit (CBU) total colony-forming unit (CFU) count both pre-cryo and post-thaw has been shown to be associated with platelet (PLT) engraftment. Pre-cryo CBUs show good growth of megakaryocytic CFUs (CFU-Mk); however, CFU-Mk have rarely been studied in post-thaw CBUs. Materials and Methods Nucleated cells (NCs) from post-thaw CB were cultured in a collagen-based assay designed to support growth of CFU-Mk. To ensure accurate counting two independent investigators evaluated four culture chambers per sample for CFU-Mk growth. Post-thaw CFU and other cellular characteristics of the CBUs were enumerated independently and compared to CFU-Mk. Results The post-thaw CBU total CFU count varied from 047 to 420--106-colonies (median, 099--106) and total CFU-Mk count ...
The effects of the ripening period (1, 3, 7, 11, 13 days), nitrite level (45, 70, 120, 170, 195 mg kg-1) and heat treatment (30, 40, 60, 80, 90°C) on counts of total aerobic mesophilic bacteria, lactic acid bacteria (LAB) and Micrococcus-Staphylococcus in sucuk were investigated using a central composite rotatable design of response surface methodology. Counts of total aerobic mesophilic bacteria and lactic acid bacteria were increased and counts ofMicrococcus-Staphylococcus were significantly decreased during the ripening period (p<0.01). Counts of all bacteria were significantly decreased by the effects of heat treatment (p<0.01). Nitrite had a significant effect on total aerobic mesophilic bacteria.Enterobacteriaceae, moulds, and yeasts were observed only in the first days of the ripening period.
Scalding has been found to lower the levels of Campylobacter on broiler carcasses. However, the numbers recovered from whole-carcass rinse samples increase following defeathering. This study was undertaken to examine the effect of a second scald applied after defeathering on microbial levels recovered from carcass rinses. Four treatments were evaluated: 1) immersion at 60 C for 28 s 30 min after defeathering, 2) immersion at 60 C for 28 s immediately after defeathering, 3) spray at 73 C for 20 s 30 min after defeathering, and 4) spray at 71 C for 20 s immediately after defeathering. As reported earlier, a significant increase in Campylobacter counts per mL whole carcass rinse was noted after carcasses were defeathered. However, when applied 30 min after defeathering, neither the immersion nor the spray second scald treatments lowered the Campylobacter counts. Likewise, neither treatment had any affect on Escherichia coli or coliform bacteria counts, even though total counts were slightly reduced by the treatments. When the second scald treatment immediately followed defeathering, the same trends were observed. Campylobacter counts after the second scald remained at the postpick levels, as did counts for E. coli and coliform bacteria, but total plate counts were slightly reduced. Overall, it would appear that a postscald treatment gentle enough not to alter the carcass appearance or meat quality would not effectively lower Campylobacter, E. coli, or coliform bacteria counts. PMID:11092344
The assumption necessary to perform ECG gated blood pool scintigraphy (EGBPS) are seemingly not valid for patients with atrial fibrillation (af), since they have wide variability in cardiac cycle length. The data were acquired in frame mode within the limits of mean heart rate of fix the first diastolic volume, and were calculated by frame count normalization (FCN) method to correct total counts in each frame. EGBPS were performed twelve patients with af, who were operated against valvular disease. The data acquired within mean heart rate +-10 % in frame mode were divided to 32 frames, and calculated total frame counts. With FCN method total frame counts from at 22nd to 32nd frame were multiplied to be equal to the average of total frame counts. FCN method could correct total frame counts at the latter frames. And there was good correlation between left ventricular ejection fraction calculated from scintigraphy and that from contrast cineangiography. Thus EGBPS with FCN method may be allow estimation of cardiac function even in subjects with af.
The role of leukocyte accumulation in the cerebrospinal fluid (CSF) in the evolution of the pathophysiological changes that occur in bacterial meningitis is unclear. Here, we investigate how leukocyte recruitment to the CSF, modulated by the leukocyte blocker fucoidin, affects the extent of brain damage and outcome in pneumococcal meningitis in rats treated with ceftriaxone from 28 h after infection. Rats treated with fucoidin from time of infection had an excess risk of a fatal outcome compared to rats not receiving fucoidin (25/63 versus 5/34, p=0.012), whereas the risk of cortical damage in surviving animals was comparable (16/44 versus 9/29, p=0.8). Pre-treatment with fucoidin attenuated CSF pleocytosis 24 h after infection (median 400 versus 800x10(6) cells/l, p=0.01) without affecting CSF bacterial counts (2.3x10(5) versus 3.6x10(5) CFU/ml, p=0.54). A significant increase in blood bacterial counts was found among rats pre-treated with fucoidin (median 9.6x10(2) versus 5.2x10(2) CFU/ml, p=0.03). Furthermore, blood bacterial count was found to be an important predictor of fatal outcome as shown by multivariate logistical regression analysis (OR 4.43, 95% CI [1.16-17.0] p=0.03). In summary, blocking leukocyte entry to the central nervous system in experimental pneumococcal meningitis compromises the survival prognosis but does not affect the risk of brain damage or level of infection in this compartment. Conversely, poorer prognosis was associated with an increase in bacterial load in blood, suggesting that leukocyte blockage affects the host's ability to control systemic infection.
The role of leukocyte accumulation in the cerebrospinal fluid (CSF) in the evolution of the pathophysiological changes that occur in bacterial meningitis is unclear. Here, we investigate how leukocyte recruitment to the CSF, modulated by the leukocyte blocker fucoidin, affects the extent of brain damage and outcome in pneumococcal meningitis in rats treated with ceftriaxone from 28 h after infection. Rats treated with fucoidin from time of infection had an excess risk of a fatal outcome compared to rats not receiving fucoidin (25/63 versus 5/34, p=0.012), whereas the risk of cortical damage in surviving animals was comparable (16/44 versus 9/29, p=0.8). Pre-treatment with fucoidin attenuated CSF pleocytosis 24 h after infection (median 400 versus 800x10(6) cells/l, p=0.01) without affecting CSF bacterial counts (2.3x10(5) versus 3.6x10(5) CFU/ml, p=0.54). A significant increase in blood bacterial counts was found among rats pre-treated with fucoidin (median 9.6x10(2) versus 5.2x10(2) CFU/ml, p=0.03). Furthermore, blood bacterial count was found to be an important predictor of fatal outcome as shown by multivariate logistical regression analysis (OR 4.43, 95% CI [1.16-17.0] p=0.03). In summary, blocking leukocyte entry to the central nervous system in experimental pneumococcal meningitis compromises the survival prognosis but does not affect the risk of brain damage or level of infection in this compartment. Conversely, poorer prognosis was associated with an increase in bacterial load in blood, suggesting that leukocyte blockage affects the host's ability to control systemic infection.
Effects of diesel exhaust on the microbiota within a tuffaceous tunnel system
The abundance and distribution of microbiota that may be impacted by diesel and diesel exhaust were investigated from three depths into the walls and invert (floor) of U12n tunnel at Rainier Mesa, Nevada Test Site, a potential geological analog of Yucca Mountain. Enumerations included total cell counts, and numbers of aerobic heterotrophic, sulfate-reducing, nitrate-reducing, and diesel-degrading bacteria. Additionally, the disappearance of total petroleum hydrocarbons was determined in microcosms containing subsurface materials that were amended with diesel fuel. Results revealed that microbes capable of utilizing diesel and diesel combustion products were present in the subsurface in both the walls and the invert of the tunnel. The abundance of specific bacterial types in the tunnel invert, a perturbed environment, was greater than that observed in the tunnel wall. Few trends of microbial distribution either into the tunnel wall or the invert were noted with the exception of aerobic heterotrophic abundance which increased with depth into the wall and decreased with depth into the invert. No correlation between microbiota and a specific introduced chemical species have yet been determined. The potential for microbial contamination of the tunnel wall during sampling was determined to be negligible by the use of fluorescently labeled latex spheres (1{mu}m in dia.) as tracers. Results indicate that additional investigations might be needed to examine the microbiota and their possible impacts on the geology and geochemistry of the subsurface, both indigenous microbiota and those microorganisms that will likely be introduced by anthropogenic activity associated with the construction of a high-level waste repository.
The aim of this study was to determine how quickly the surface of a refrigerated supermarket serve over counter becomes loaded with bacteria. New material made of polyvinyl chloride or stainless steel was placed on the surface on which foodstuffs are displayed for sale. One to three samples per week for 7weeks were collected on gauze pads. CFUs were counted and total cells were quantified by real-time PCR. "Viable" cells using real-time PCR following pre-treatment with ethidium monoazide were quantified on stainless steel. Attachment strengths were assessed at the end of the experiment by constructing detachment curves. Whatever the material, on day 1 the microbial load reached values near those observed in the following weeks i.e. 10(3)-10(4)logtotalcells/cm(2). The number of cells deposited in one week was compensated for by the small reduction obtained by cleaning and disinfection (C&D). The mean difference between total and viable cells was 0.54logCFUs/cm(2). A big drop in CFUs following C&D was observed at the beginning of the experiment, despite no visible decrease in the number of viable cells, but the CFU reduction decreased over time. Nevertheless, the low efficiency of C&D on the dominant microbiota did not indicate the fate of pathogenic bacteria on these materials. Our data suggest that dead cells do not adhere quite so well as viable cells. Although no growth was observed and the attached bacterial community cannot therefore be considered a biofilm, attached cells shared certain properties attributed to biofilms i.e. their resistance to C&D increased over time and they followed a biphasic detachment curve. PMID:23107495
Microbial communities in the deep drill cores from the Chinese Continent Scientific Drilling were analyzed with culture-independent and dependent techniques. Genomic DNA was extracted from two metamorphic rocks: S1 from 430 and S13 from 1033 meters below the ground surface. The 16S rRNA gene was amplified by polymerase chain reaction (PCR) followed by cloning and sequencing. The total cell number was counted using the 4',6-diamidino-2-phenylindole (DAPI) staining and biomass of two specific bacteria were quantified using real-time PCR. Enrichment was set up for a rock from 3911 meters below the surface in medium for authotrophic methanogens (i.e., CO2 + H2). The total cell number in S13 was 1.0 × 104 cells per gram of rock. 16S rRNA gene analysis indicated that low G + C Gram positive sequences were dominant (50 percent of all 54 clone sequenced) followed by the alpha-, beta, and gamma-Proteobacteria. Within the low G + C Gram positive bacteria, most clone sequences were similar to species of Bacillus from various natural environments (deserts, rivers etc.). Within the Proteobacteria, our clone sequences were similar to species of Acinetobacter, Acidovorax, and Aeromonas. The RT-RCP results showed that biomass of two particular clone sequences (CCSD1305, similar to Aeromonas caviae and CCSD1307, similar to Acidovorax facilis) was 95 and 1258 cells/g, respectively. A bacterial isolate was obtained from the 3911-m rock in methanogenic medium. It was Gram negative with no flagella, immobile, and facultative anaerobic, and grows optimally at 65oC. Phylogenetic analysis indicated that it was closely related to the genus of Bacillus. Physiological tests further revealed that it was a strain of Bacillus caldotenax.
Abstract in portuguese CONTEXTO E OBJETIVO: Peritonite bacteriana espontânea (PBE) é uma freqüente e grave complicação em pacientes cirróticos com ascite. Vem sendo proposto o uso de fitas reagente para esterase leucocitária, utilizadas para diagnóstico de infecção urinária, como instrumento para diagnosticar PBE. O objetivo deste estudo é avaliar a sensibilidade e a especificidade da fita reagente Combur Test® UX no diagnóstico de PBE em pacientes cirróticos com ascite. TIPO DE (more) ESTUDO E LOCAL: Estudo prospectivo, realizado no Hospital Universitário Walter Cantídio, Fortaleza, Ceará, Brasil. MÉTODOS: Quarenta e dois pacientes consecutivos, não selecionados (32 homens, com média de idade de 51,7 ± anos) foram incluídos e um total de 100 paracenteses foram realizadas. O líquido ascítico foi avaliado pela fita reagente (Combur Test® UX), citologia, contagem de neutrófilos, linfócitos, testes bioquímicos e cultura. As fitas reagentes foram consideradas positivas se havia mudança na cor para roxo na escala colorimétrica fornecida pelo fabricante. RESULTADOS: Foram diagnosticados nove pacientes com PBE pela citologia (> 250 neutrófilos/mm³), estando a fita Combur Test® UX positiva em todos os nove pacientes. Em uma amostra o teste da fita foi positivo, embora a contagem de neutrófilos fosse Abstract in english CONTEXT AND OBJECTIVE: Spontaneous bacterial peritonitis (SBP) is a frequent and severe complication of cirrhotic patients with ascites. It has been proposed that the reagent strip for leukocyte esterase designed for the testing of urine (Combur test® UX) could be a useful tool for diagnosing SPB. The aim of this study was to assess the sensitivity and specificity of urine test strips for diagnosing SBP in cirrhotic patients with ascites. DESIGN AND SETTING: Prospective (more) study, at a university hospital in northeastern Brazil. METHODS: Forty-two unselected consecutive cirrhotic patients (32 males; mean age: 51.7 ± years) were included, and a total of 100 paracenteses were performed. All ascitic fluid samples were analyzed using the reagent strip and cytology, neutrophils, lymphocyte count, appropriate biochemical tests and culturing. The strips were considered positive if the color became purple on a colorimetric scale. RESULTS: Nine patients were diagnosed with SBP using cytology (> 250 neutrophils/mm³), and the strips were positive for all these nine patients with SBP. In one sample, the strip was positive but the neutrophil count was less than 250 cells/mm³. For 86 samples, both the strips and cytology were negative. At the threshold of 250 neutrophils/mm³ in ascitic fluid, the sensitivity, specificity, positive predictive value and negative predictive value for the strips were respectively 100%, 98.9%, 92.3% and 100%. CONCLUSION: The Combur test® UX urine screening test is a very sensitive and specific method for diagnosing SBP in cirrhotic patients with ascites.
Brood Year 2004: Johnson Creek Chinook Salmon Supplementation Report, June 2004 through March 2006.
The Nez Perce Tribe, through funding provided by the Bonneville Power Administration, has implemented a small scale chinook salmon supplementation program on Johnson Creek, a tributary in the South Fork of the Salmon River, Idaho. The Johnson Creek Artificial Propagation Enhancement project was established to enhance the number of threatened Snake River spring/summer chinook salmon (Oncorhynchus tshawytscha) returning to Johnson Creek to spawn through artificial propagation. This was the sixth season of adult chinook broodstock collection in Johnson Creek following collections in 1998, 2000, 2001, 2002, and 2003. Weir installation was completed on June 21, 2004 with the first chinook captured on June 22, 2004 and the last fish captured on September 6, 2004. The weir was removed on September 18, 2004. A total of 338 adult chinook, including jacks, were captured during the season. Of these, 211 were of natural origin, 111 were hatchery origin Johnson Creek supplementation fish, and 16 were adipose fin clipped fish from other hatchery operations and therefore strays into Johnson Creek. Over the course of the run, 57 natural origin Johnson Creek adult chinook were retained for broodstock, transported to the South Fork Salmon River adult holding and spawning facility and held until spawned. The remaining natural origin Johnson Creek fish along with all the Johnson Creek supplementation fish were released upstream of the weir to spawn naturally. Twenty-seven Johnson Creek females were artificially spawned with 25 Johnson Creek males. Four females were diagnosed with high bacterial kidney disease levels resulting in their eggs being culled. The 27 females produced 116,598 green eggs, 16,531 green eggs were culled, with an average eye-up rate of 90.6% resulting in 90,647 eyed eggs. Juvenile fish were reared indoors at the McCall Fish Hatchery until November 2005 and then transferred to the outdoor rearing facilities during the Visual Implant Elastomer tagging operation. These fish continued rearing in the outdoor collection basin until release in March 2006. All of these fish were marked with Coded Wire Tags and Visual Implant Elastomer tags. In addition 12,056 of the smolts released were also tagged with Passive Integrated Transponder tags. Hand counts provided by marking crews were used to amend the number of juvenile salmon released from the original egg count. A total of 90,450 smolts were released directly into Johnson Creek on March 13 through 15, 2006.
Abstract in spanish RESUMEN Este estudio identifica bacterias marinas obtenidas de tres sitios costeros de la ciudad de Comodoro Rivadavia, sur de Argentina. Se tomaron muestras de agua de mar y sedimento del intermareal. Dos de los sitios se ubicaron cerca de desagües cloacales (CR1, CR2) y el tercero (CR3) fue cerca de una boya de carga de hidrocarburos. Se realizaron recuentos bacterianos en cuatro medios de cultivo: BBR, BRN, medio mineral con petróleo gas oil y ENDO para coliformes. L (more) as bacterias fueron identificadas utilizando ácidos grasos metíl esteres. Los recuentos de coliformes totales y fecales fueron positivos en los sitios CR1 y CR2 y negativos para CR3 con excepción de la estación de otoño. Se aislaron 469 cepas a las que se les realizó la extracción de ácidos grasos e identificación. El sistema identificó 37 géneros y 54 especies en solo 236 cepas. Las restantes cepas no fueron identificadas debido a que no se encontraron en la base de datos Sherlock. Pseudoalteromonas fue el género que más frecuentemente se encontró aislado y el grupo de las enterobacterias estuvo integrado por Citrobacter, Enterobacter y Escherichia. El análisis de componentes principales asoció el invierno a las cepas Gram positivas y el otoño se asoció con la mayor biodiversidad de géneros. Abstract in english ABSTRACT This study identifies marine bacteria obtained from three sites along Comodoro Rivadavia coast, south of Argentina. Seawater and intertidal sediment samples were collected. Two of the sites were located close to the city sewage system (CR1, CR2) and the third one (CR3) was near from an oil buoy. Bacterial counts were performed on four culture media: BBR, BRN, mineral medium with crude oil and gas oil and ENDO for coliforms. The identification of bacteria was perf (more) ormed by using fatty acid methyl esters. The counts resulted positive to total coliforms and faecal coliforms in sites CR1 and CR2 and resulted negative in site CR3 except in autumn. We isolated 469 strains, to which a fatty acid extraction and identification were performed. The system identified 37 genera and 54 species in only 236 strains. The other strains were unidentified because they were not found in Sherlock data base. Pseudoalteromonas was the genus frequently found isolated and the enterobacteria group was conformed by Citrobacter, Enterobacter and Escherichia. The principal components analysis related the winter season to Gram positive strain, and autumn season was asociated to the biggest biodiversity of genera.
Abstract in portuguese Analisou-se a evolução anual da qualidade de leite cru refrigerado pelo levantamento e análise estatística do banco de dados das análises individuais de leite dos tanques refrigeradores, computadas mensalmente entre abril de 2002 e dezembro de 2008 em uma indústria de Minas Gerais. O volume de leite em conformidade com a IN51 para contagem bacteriana total para o ano de 2008 aumentou de 74,3% em 2002 para 85,8% em 2008. Considerando-se a IN51 para o ano de 2011, ess (more) es valores seriam de 30,5% e 46,6%, respectivamente. O volume de leite em conformidade com a IN51 para contagem de células somáticas reduziu-se de 93,5% em 2002 para 90,1% em 2008. Para o ano de 2011, esses valores seriam de 64,9 e 60,5%, respectivamente. Em relação à composição sólida do leite, o volume de leite em conformidade com a IN51 para os teores de gordura, de proteína e de extrato seco desengordurado foi de 95,2%, 98,2% e 89,6%, respectivamente. As variações sazonais influenciaram a qualidade do leite cru refrigerado de tanques de expansão. A implantação de um sistema de pagamento por qualidade do leite ao produtor foi eficaz na melhoria dos índices de qualidade da matéria-prima. Abstract in english The present study aimed to analyze the annual evolution of cooled raw milk quality, through analytical analysis of the data base of individual bulk milk tanks analysis, monthly computed from April/2002 to December/2008 at a dairy industry in Minas Gerais. The mean volume of milk in compliance with IN51 for total bacterial count for year 2008 increased from 74.3% in 2002 to 85.8% in 2008. Considering IN51 for year 2011, these values would be 30.5% and 46.6%, respectively. (more) The mean volume of milk in compliance with IN51 for somatic cells count reduced from 93.5% in 2002 to 90.1% in 2008. Considering the legal standard for the year of 2011, these values would be 64.9 and 60.5%, respectively. In relation to the solid composition of milk, the mean volume of milk in compliance with IN51 for fat, protein and solids nonfat were 95.2%, 98.2% and 89.6%, respectively. The season variations affected the quality of the bulk tank cooled raw milk from bulk tanks. The implantation of a payment system for the quality of milk to the producer revealed to be efficient in its objective to improve the quality indexes of raw milk.
Although it is known that Palk Bay sediments harbor diverse and novel bacteria with important ecological and environmental functions, a comprehensive view of their molecular diversity is still lacking. In the present study, bacterial diversity in Palk Bay sediments was characterized using the molecular method terminal-restriction fragment length polymorphisms (T-RFLP). The bacterial assemblages detected by T-RFLP analysis revealed that the nearshore sediment harbored high number of bacterial count, whereas the 2.5-m sediment harbored diverse and distinct bacterial composition with fine heterogeneity. The major bacterial groups detected in all the three sediment samples were Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria (including alpha (?), gamma (?), delta (?), and epsilon (?)-Proteobacteria), and uncultured bacteria. This is the first study that reveals the presence of Bacteroidetes, delta (?)- and epsilon (?)-Proteobacteria, and uncultured bacteria in Palk Bay sediments. The hitherto unexplored wide microbial diversity of Palk Bay coastal area was unraveled in the current study through culture-independent approach. These data suggest that the continued use of cultivation-independent techniques will undoubtedly lead to the discovery of additional bacterial diversity and provide a direct means to learn more about the ecophysiology and biotechnological potential of Palk Bay coastal area. PMID:22528645
Despite the existence of several methods for the diagnosis of oral infectious diseases, few rapid and quantitative methods exist for discriminating between live and dead bacterial cells in oral clinical samples. In this study, we characterized a light-emitting diode (LED) fluorescence microscopic technique for quantifying live and dead oral bacterial cells stained with 4',6'-deamidino-2-phenyllindole and propidium iodide. Four bacterial strains representative of the human oral microflora were used in this study. In addition, saliva and subgingival fluid specimens were collected from healthy volunteers. Saliva was obtained from the donors without stimulation, whereas subgingival fluid was obtained by inserting a sterile endodontic paper point into the subgingival sites of the first molar. The samples were cultured on agar plates and subjected to LED microscopy. The correlations between both methods were analyzed. The number of live bacterial cells as determined by LED-based fluorescence microscopy and standard colony counts on agar plates correlated well for the known oral bacterial strains and bacterial cells in the clinical specimens. The LED illumination method characterized in this study can be used for the rapid enumeration of living and dead cells. However, to show specificity, this method requires further innovations.
The main objective of this study was to assess the impact of pollution on seabed bacterial diversity, structure and activity in the Port of Livorno. Samples of seabed sediments taken from five selected sites within the port were subjected to chemical analyses, enzymatic activity detection, bacterial count and biomolecular analysis. Five different statistics were used to correlate the level of contamination with the detected biological indicators. The results showed that the port is mainly contaminated by variable levels of petroleum hydrocarbons and heavy metals, which affect the structure and activity of the bacterial population. Irrespective of pollution levels, the bacterial diversity did not diverge significantly among the assessed sites and samples, and no dominance was observed. The type of impact of hydrocarbons and heavy metals was controversial, thus enforcing the supposition that the structure of the bacterial community is mainly driven by the levels of nutrients. The combined use of chemical and biological essays resulted in an in-depth observation and analysis of the existing links between pollution macro-indicators and biological response of seabed bacterial communities. PMID:22542235
Structure and seasonal dynamics of bacterial communities in three urban rivers in China
Although a large number of recent ecological studies have focused on freshwater bacterioplankton populations, knowledge of the primary factors influencing bacterial communities in urban rivers is limited. Bacterial community structure in three rivers located in Shanghai city was studied over a 1-year period using denaturing gradient gel electrophoresis (DGGE). Subsurface samples were collected every 2 months from two study sites in each river. Water was characterized when biological samples were collected by measuring temperature, pH, chloride ion, total dissolved solids (TDS), total N and total P. complex DGGE band patterns indicated high bacterial diversity in the rivers. Analysis of similarity (ANOSIM) showed that variation of the bacterial communities was higher between rivers than it...
Untersuchungen zum mikrobiellen und viralen Kontaminationsstatus von Garnelen aus Aquakultur
Abstract: In this study 111 samples of raw imported aqua-cultured shrimps have been examined for bacterial pathogens and for pathogen viruses. The samples originated from South-East Asia except for eight Latin-American samples. Most samples were taken from Bangladesh (n=40). The bacteriological quality of these samples was analysed in terms of aerobic plate count, Escherichia coli, Staphylococcus aureus, Salmonella spp., Listeria monocytogenes and Vibrio species. Rotavirus, norovirus and hepatitis A-Virus were detected by using a nested RT-PCR. The aerobic plate count was found to be in a range between 4,8?102 to 1,3?109 cfu/g. Fourteen samples (12,6%) showed an aerobic plate count >107 cfu/g. One sample was found to be contaminated with Escherichia coli at a level of 1,9?103 cfu/g. Staphy...
The behaviour of Listeria monocytogenes Scott A artificially inoculated into Brazilian Minas Frescal cheese manufactured with the addition of a lactic culture or by direct acidification with lactic acid was evaluated at 5 and 10degreeC for 25 days. In cheese produced with a lactic culture, the counts remained almost unchanged during storage, whereas cheeses produced by direct acidification presented an increase in the counts of 2-3 log cycles. The profiles of the lactic bacterial counts, associated with those of L. monocytogenes, show a strong influence of the competitive starter culture on the survival of L. monocytogenes. This suggests that the addition of starter culture is an efficient way to control the growth of L. monocytogenes in these products.
The effects of storage temperature (20, 30 and 40degreeC), inoculum type (pure spores, an equal mix of spores and vegetative cells and pure vegetative cells) and water content (20%, 30% and 40%) on the survival and spore formation of the biocontrol agent, Paenibacillus polymyxa SQR-21, in a bioorganic fertilizer were modeled in a 3x3x3 factorial design. Bacterial and spore populations were monitored by plate count and fluorescence in situ hybridization (FISH). Temperature significantly affected survival of inoculants after storage for 60days. Populations were 1.48 (plate counting) or 1.71 (FISH) times greater when stored at 20degreeC compared to 40degreeC. Inoculation of the fertilizer with pure spores led to the highest spore formation percentage (67.6% for plate counting, 94.2% for FISH)...
Investigations into the micro-ecology of oral malodour in man and companion animals.
The loads and locations of bacterial types associated with oral malodour on the tongue surface and gingival crevice were investigated in man and the dog respectively. In the human study, samples were taken from 50 subjects with brushes at the dorsal anterior, dorsal middle, dorsal posterior, dorsal posterior to the circumvallate papillae (DPCP), lateral posterior and ventral posterior (VP) surfaces, and cultured appropriately. Malodour was assessed by trained judges. Mean volatile sulfur compound (VSC) producing bacterial counts (colony forming units/brush × 10(5)) were found to be highest (88.94) and lowest (0.33) at the DPCP and VP sites respectively. Anaerobic, gram-negative and VSC counts at DPCP surfaces increased with malodour intensity, whereas aerobic and S. salivarius counts decreased. The prevalence and populations of the VSC producing Porphyromonas and Prevotella species were determined in the dental plaque from 34 dogs. Porphyromonas gulae and Prevotella intermedia were present in 68% and 44% of dogs, and 47% and 23% of plaque samples respectively. P. gulae and Prev. intermedia counts increased with plaque quantity (P < 0.05) and gingivitis (P < 0.1). The close association observed between canine periodontal disease and measurements of oral malodour is supported. PMID:21386208
Abstract in spanish Estudiamos la capacidad que tienen las bacterias de sedimentos profundos en la Bahía de Bengala, India, de disolver los fosfatos que juegan un papel clave en los ciclos biogeoquímicos del mar. Recolectamos muestras en 33 estaciones ubicadas entre 10°36?N - 20°01?N y 79°59?E - 87°30?E en once transectos y tres profundidades, i.e. ca. 200 m, 500 m, 1000 m. Los conteos totales de bacterias heterotróficas fueron de 0.42 a 37.38x10(4) CFU g-1 (peso seco) de sediment (more) o. De las cepas evaluadas, un 7.57% disuelven fosfato. Los géneros con esta características fueron Pseudomonas, Bacillus, Vibrio, Alcaligenes, Micrococcus, Corynebacterium y Flavobacterium. Abstract in english Microorganisms play a vital role in the biogeochemical cycles of various marine environments, but studies on occurrence and distribution of such bacteria in the marine environment from India are meager. We studied the phosphate solubilizing property of bacteria from the deep sea sediment of Bay of Bengal, India, to understand their role in phosphorous cycle (and thereby the benthic productivity of the deep sea environment). Sediment samples were obtained from 33 stations (more) between 10°36? N - 20°01? N and 79°59? E - 87°30? E along 11 transects at 3 different depths i.e. ca. 200 m, 500 m, 1000 m in each transect. Total heterotrophic bacterial (THB) counts ranged from 0.42 to 37.38x10(4) CFU g-1 dry sediment weight. Of the isolates tested, 7.57% showed the phosphate solubilizing property. The phosphate solubilizing bacterial genera were Pseudomonas, Bacillus, Vibrio, Alcaligenes, Micrococcus, Corynebacterium and Flavobacterium. These strains are good solubilizers of phosphates which ultimately may play a major role in the biogeochemical cycle and the benthic productivity of the Exclusive Economic Zone (EEZ) of Bay of Bengal, because this enzyme is important for the slow, but steady regeneration of phosphate and organic carbon in the deep sea. Rev. Biol. Trop. 55 (1): 1-9. Epub 2007 March. 31.
Vibrio harveyi: a pathogen of penaeid shrimps and fish in Venezuela.
Seasonal plankton blooms correlate with occurrence of cholera in Bangladesh, although the mechanism of how dormant Vibrio cholerae, enduring interepidemic period in biofilms and plankton, initiates seasonal cholera is not fully understood. In this study, laboratory microcosms prepared with estuarine Mathbaria water (MW) samples supported active growth of toxigenic V. cholerae O1 up to 7?weeks as opposed to 6?months when microcosms were supplemented with dehydrated shrimp chitin chips (CC) as the single source of nutrient. Bacterial counting and detection of wbe and ctxA genes were done employing culture, direct fluorescent antibody (DFA) assay, and multiplex-polymerase chain reaction methods. In MW microcosm, the aqueous phase became clear as the non-culturable cells settled, whereas the aqueous phase of the MW–CC microcosm became turbid from bacterial growth stimulated by chitin. Bacterial chitin degradation and biofilm formation proceeded from an initial steady state to a gradually declining bacterial culturable count. V. cholerae within the microenvironments of chitin and chitin-associated biofilms remained metabolically active even in a high acidic environment without losing either viability or virulence. It is concluded that the abundance of chitin that occurs during blooms plays an important role in the aquatic life cycle of V. cholerae and, ultimately, in the seasonal transmission of cholera. PMID:8662185
Role of Shrimp Chitin in the Ecology of Toxigenic Vibrio cholerae and Cholera Transmission.
Seasonal plankton blooms correlate with occurrence of cholera in Bangladesh, although the mechanism of how dormant Vibrio cholerae, enduring interepidemic period in biofilms and plankton, initiates seasonal cholera is not fully understood. In this study, laboratory microcosms prepared with estuarine Mathbaria water (MW) samples supported active growth of toxigenic V. cholerae O1 up to 7?weeks as opposed to 6?months when microcosms were supplemented with dehydrated shrimp chitin chips (CC) as the single source of nutrient. Bacterial counting and detection of wbe and ctxA genes were done employing culture, direct fluorescent antibody (DFA) assay, and multiplex-polymerase chain reaction methods. In MW microcosm, the aqueous phase became clear as the non-culturable cells settled, whereas the aqueous phase of the MW-CC microcosm became turbid from bacterial growth stimulated by chitin. Bacterial chitin degradation and biofilm formation proceeded from an initial steady state to a gradually declining bacterial culturable count. V. cholerae within the microenvironments of chitin and chitin-associated biofilms remained metabolically active even in a high acidic environment without losing either viability or virulence. It is concluded that the abundance of chitin that occurs during blooms plays an important role in the aquatic life cycle of V. cholerae and, ultimately, in the seasonal transmission of cholera. PMID:22319512
This work was aimed at isolating and identifying the microbiota present during the semi-dry method of coffee processing using polyphasic methods and to evaluate microbial diversity with PCR-DGGE. Samples of Coffea arabica L. were collected during different processing stages in southern Minas Gerais, Brazil. The bacterial and fungal isolates were phenotypically characterised and grouped according to the ARDRA technique, in which the 16-23S and ITS1-5.8S regions of the rDNA were sequenced for species identification. The bacterial counts varied from 3.7 to 7 log CFU g(-1). The yeast counts ranged from 3.4 to 6.9 log CFU g(-1), and the filamentous fungal population varied from 2 to 3.7 log CFU g(-1). Bacillus subtilis, Escherichia coli, Enterobacter agglomerans, Bacillus cereus and Klebsiella pneumoniae were the predominant bacteria detected during the processing of the coffee, and Pichia anomala, Torulaspora delbrueckii and Rhodotorula mucilaginosa were the dominant yeasts. All of the yeast and bacterial species detected by PCR-DGGE were isolated using culture-dependent methods, with the exception of one uncultivable bacterial species. Aspergillus was the most common genus among the filamentous fungal isolates. The use of polyphasic methods allowed a better characterization of the microbiota that is naturally present in semi-dry processed coffee. PMID:20832694
The authors compare the efficacy of sol to gel systems and marketed eye drops of Pefloxacin mesylate (PM) in the patients with bacterial conjunctivitis. It was an open, comparative, 3-treatment, randomized, parallel study. Formulations were tested on 15 patients with bacterial conjunctivitis. Each formulation was tested on 5 patients. Patients receiving marketed eye drops were instructed to use 2 drops, 4 times a day for 7 days. Patients receiving sol to gel were instructed to use 1 drop every 12 hours for 7 days. Pharmacodynamic parameters, based on a scale of rating, were used to assess the improvement in conjunctivitis on treatment with formulations. Conjunctival swabs were taken from eyes of patients, and viable counts were performed at days 0, 3, 5, and 7. Statistical analysis of the pharmacodynamic data indicated that both sol to gel systems used were more effective than marketed eye drops in the treatment of bacterial conjunctivitis. Results of the viable count revealed that a faster reduction in the number of colony-forming units (cfu) were obtained with both sol to gel systems, compared to marketed eye drops. It can be concluded that both sol to gel systems were superior to marketed eye drops in the treatment of bacterial conjunctivitis. PMID:15321031
Staphylococcal infections associated with catheter and prosthetic implants are difficult to eradicate and often lead to chronic infections. Development of novel antibacterial therapies requires simple, reliable, and relevant models for infection. Using bioluminescent Staphylococcus aureus, we have adapted the existing foreign-body and deep-wound mouse models of staphylococcal infection to allow real-time monitoring of the bacterial colonization of catheters or tissues. This approach also enables kinetic measurements of bacterial growth and clearance in each infected animal. Persistence of infection was observed throughout the course of the study until termination of the experiment at day 16 in a deep-wound model and day 21 in the foreign-body model, providing sufficient time to test the effects of antibacterial compounds. The usefulness of both animal models was assessed by using linezolid as a test compound and comparing bioluminescent measurements to bacterial counts. In the foreign-body model, a three-dose antibiotic regimen (2, 5, and 24 h after infection) resulted in a decrease in both luminescence and bacterial counts recovered from the implant compared to those of the mock-treated infected mice. In addition, linezolid treatment prevented the formation of subcutaneous abscesses, although it did not completely resolve the infection. In the thigh model, the same treatment regimen resulted in complete resolution of the luminescent signal, which correlated with clearance of the bacteria from the thighs. PMID:12936968
Eyelid skin disinfecting and conjunctival bacteria in cataract surgery.
Purpose:? To evaluate the effect on conjunctival micro-organisms of chlorhexidine alcohol 0.5% eyelid wash in cataract patients. Methods:? In this single-centre experimental study, 120 patients scheduled to undergo cataract operation were cultured in the conjunctiva before the operation and after the insertion of the intraocular lens. Bacterial samples for aerobic and anaerobic cultures were taken with a polyvinyl alcohol pad and transported in peptone water to the microbiological laboratory where they were analysed in a blinded fashion. Half of the patients received a standardized eyelid scrub with chlorhexidine alcohol 0.5%, while the rest did not. The conjunctiva of all patients was rinsed preoperatively with chlorhexidine solution 0.05%. Results:? In all the between-group comparisons, the treated eyelid group had slightly lower bacterial counts than the control group on the postoperative samples, but differences were far from statistically significant. Within-group comparisons revealed statistically significant reduction in colonies and species between the preoperative and postoperative sampling. Conclusion:? In this experimental culture study, no evidence was found to suggest that preoperative eyelid chlorhexidine alcohol wash is effective in further reducing bacterial counts in the conjunctiva when the conjunctiva itself is rinsed preoperatively with chlorhexidine solution. The present results, however, do not contradict that the wash may be of some marginal help in reducing bacterial contamination of the operation field. Consequently, this part of the prophylactic protocol is still in practice in our institution. PMID:22471311
In this chapter, an overview of photocatalytic bacterial inactivation is given together with recent relevant literature examples and references. The most important parameters influencing the process are classified in physicochemical, biological, and engineering aspects. Experiments carried out at laboratory and field scale are illustrated and discussed. Limitations, advantages, and drawbacks are pointed out. Sensitivity of bacteria to solar disinfection in the absence and presence of TiO2 can vary for each species of microorganism according to strain, stage of the culture, growth medium, initial bacterial load, and type of plating medium used for bacterial cultivation and counting. Physicochemical parameters and reactor design among others also influence the process. However, to comply with requirements in the disinfection systems, it is important to determine for each condition the length of the irradiation period or effective disinfection time (EDT) that ensures death of the bacteria and consequently the end of the treatment.
Background Probiotics may exert beneficial effects in the gastrointestinal tract. This randomized trial investigated the effect of the probiotic Lactobacillus plantarum 299v on the intestinal load of potentially pathogenic bacteria, bacterial translocation, and cell proliferation in elective colon surgery. Methods Seventy-five patients were randomized to pre- and postoperative oral intake of Lactobacillus plantarum 299v or placebo. Rectal swabs and mucosal biopsies were taken before the start of intake, after 1?week, at surgery, and after 6?days, weeks, and months. Viable counts were quantified for clostridia, Enterobacteriaceae, Gram-negative anaerobes, and lactobacilli. Bacterial translocation was determined by the analysis of bacterial DNA genes in mesenteric lymph nodes. Ki-67 was used...
We performed a cohort study of children who survived bacterial meningitis after the neonatal period at a single pediatric center in France over a 10-year period (1995?2004) to identify predictors of death and long-term neurological deficits in children with bacterial meningitis. We performed multivariate regression to determine independent predictors of death and neurologic deficits. We identified 101 children with bacterial meningitis of which 19 died during initial hospitalization. Need for mechanical ventilation [hazard ratio (HR) 11.5, 95?% confidence interval (CI) 2.4?55.5)] and thrombocytopenia defined as a platelet count <150???109?per liter (HR 0.6, 95?% CI 0.4?0.9) at presentation were associated with death during initial hospitalization. At final assessment, 42 of the 70 survivor...
Medicinal smoke reduces airborne bacteria
This study represents a comprehensive analysis and scientific validation of our ancient knowledge about the effect of ethnopharmacological aspects of natural products' smoke for therapy and health care on airborne bacterial composition and dynamics, using the Biolog microplate panels and Microlog database. We have observed that 1h treatment of medicinal smoke emanated by burning wood and a mixture of odoriferous and medicinal herbs (havan samagri=material used in oblation to fire all over India), on aerial bacterial population caused over 94% reduction of bacterial counts by 60min and the ability of the smoke to purify or disinfect the air and to make the environment cleaner was maintained up to 24h in the closed room. Absence of pathogenic bacteria Corynebacterium urealyticum, Curtobacter...
Bacterial diversity on the surface of potato tubers in soil and the influence of the plant genotype
Abstract The surface of tubers might be a reservoir for bacteria that are disseminated with seed potatoes or that affect postharvest damage. The numbers of culturable bacteria and their antagonistic potential, as well as bacterial community fingerprints were analysed from tubers of seven field-grown potato genotypes, including two lines with tuber-accumulated zeaxanthin. The plant genotype significantly affected the number of culturable bacteria only at one field site. Zeaxanthin had no effect on the bacterial plate counts. In dual culture, 72 of 700 bacterial isolates inhibited at least one of the potato pathogens Rhizoctonia solani, Verticillium dahliae or Phytophthora infestans, 12 of them suppressing all three. Most of these antagonists were identified as Bacillus or Streptomyces. From...
Abstract The effect of tributyltin (TBT) on growth and metabolic activity of three estuarine bacteria with different TBT resistance profiles was investigated in an organic-rich culture medium (TSB) and in phosphate buffered saline (PBS) buffer. Exposure to TBT was assessed by determining its effect on growth (OD600 nm measurement), bacterial productivity (leucine incorporation), viability (CFU counts), aggregation and cell size (from Live/Dead analysis), ATP and NADH concentrations. TBT exposure resulted in decrease of bacterial density, cell size, and metabolic activity. In addition, cell aggregates were observed in the TBT-treated cultures. TBT strongly affected bacterial cell metabolism and seemed to exert an effect on its equilibrium, interfering with cell activity. Also, TBT toxicity ...
LAS degradability by marine biofilms derived from seawater in Spain and Sweden
Marine biofilms were established on glass beads with or without deliberate pre-exposure to LAS (20?g/L) in Spain (Cadiz) and Sweden (Kristineberg). The ability of each community to mineralize LAS (100?g/L) was then assessed in biometers at four experimental temperatures (between 6 and 21°C). Genetic diversity and biomass of the biofilms were assessed by genetic fingerprinting (DGGE) and direct bacterial counts. With biofilms from Sweden, where LAS was not detected in seawater (n=3), deliberate pre-exposure to LAS resulted in lower genetic diversity and higher mineralization rate constant; however, with biofilms from Spain, where 6.4±3.9?gLAS/L (n=3) was measured during the colonization, pre-exposure did not affect the bacterial community. Bacterial a...
Some silage inoculants help to improve silage quality and promote an increase in milk production, possibly through altering the rumen microflora. We hypothesized that rumen bacterial community composition (BCC) would be different in cows fed alfalfa ensiled with the inoculant Lactobacillus plantarum MTD/1 (LP) compared with those fed alfalfa ensiled without the inoculant (Ctrl). Eight ruminally cannulated Holstein cows were allotted to 2 diets (Ctrl or LP) in a double crossover design with four 28-d periods. Diets were formulated to contain (% dry matter basis) 28.0% neutral detergent fiber and 16.2% crude protein, and contained alfalfa silage, 50.9; corn silage, 20.6; high-moisture shelled corn, 21.4; soy hulls, 4.7; plus minerals and vitamins, 2.4. Ruminal digesta were collected just before feeding on 3 consecutive days near the end of each period, and were separated into solid and liquid phases. Microbial DNA was extracted from each phase, amplified by PCR using domain-level bacterial primers, and subjected to automated ribosomal intergenic spacer analysis. The pH was 4.56 and 4.86 and the lactate-to-acetate ratio 9.8 and 4.4, respectively, for the treated and untreated alfalfa silages. Dry matter intakes and milk production data were not influenced by diets but showed a cow effect. Total volatile fatty acids (mM) tended to be greater for LP compared with Ctrl. Individual volatile fatty acids were not influenced by diets but showed a significant cow effect. Ruminal acetate (mol/100 mol) and acetate-to-propionate ratio were lower and propionate (mol/100 mol) greater for the 2 milk fat-depressed (MFD; ribosomal intergenic spacer analysis profile across the 188 samples revealed that the first 2 components contributed 7.1 and 3.8% to the total variation in the profile. The ordination points representing the liquid and solid phases clustered separately, indicating that these phases differed in BCC. The analysis of similarity data showed differences between Ctrl and LP. The lactic acid bacterial counts (log(10) cfu/g of wet silage) were 3.94 and 4.53 for the untreated and treated silage, respectively, at ensiling. The relative population size (RPS) of L. plantarum, determined by real-time PCR of 16S rRNA gene copies, was greater in LP compared with Ctrl. The ordination points corresponding to certain individual cows clustered separately, and the most distinctive bacterial communities were those associated with MFD cows. The RPS of Megasphaera elsdenii was greater in 1 of the 2 MFD cows, although mean RPS of M. elsdenii did not differ between the treatments. In addition to the differences in rumen BCC between LP and Ctrl, MFD cows also displayed differences in BCC compared with cows with normal milk fat yield. PMID:22192212
Three methods for the simultaneous determination of [sup 89]Sr and [sup 90]Sr are compared under the aspect of low [sup 90]Sr activities and high [sup 89]Sr/[sup 90]Sr ratios as expected in nuclear emergency situations: (i) Liquid-scintillation counting with two pulse height windows, (ii) a combination of Cerenkov-radiation and liquid-scintillation counting with open windows, and (iii) the combination of Cerenkov-light and scintillation counting with two windows set during liquid-scintillation counting, the higher one adjusted to [sup 90]Y only. The third method is accurate to [+-]20% for [sup 89]Sr/[sup 90]Sr ratios up to 15 and at [sup 90]Sr disintegration rates down to 0.15 Bq applying a total counting time of about six hours. (orig.)
We studied whether the use of T-lymphocyte CD4 (CD4) absolute count instead of CD4 percentage could affect the decision process regarding HAART initiation in African HIV-infected pregnant women. A prospective cohort in Abidjan, Cote d'Ivoire before HAART was available. Participating women received a perinatal antiretroviral prophylaxis (zidovudine + single-dose of nevirapine). CD4 count and percentage were measured by flow cytometry at baseline (32 weeks of amenorrhea) and at 1 month after delivery. A signed-rank test was used to compare the distributions of the CD4 absolute count and percentage values. A total of 325 HIV-1-infected pregnant women were included. At baseline, their median CD4 count was 355 cells/mm3 and the median CD4 percentage was 24.8%; 17.8% of women had a CD4 count <20...
Prognostic Importance of the Mitotic Marker Phosphohistone H3 in Cutaneous Nodular Melanoma
Mitotic count is a known prognostic predictor in cutaneous melanoma, and is included in the current American Joint Committee on Cancer tumor-node-metastasis (TNM) staging system. The mitotic marker phosphohistone H3 (PHH3) is considered to facilitate counting of mitosis, and the purpose of this study was to evaluate the prognostic significance and strength of PHH3 in comparison with standard mitotic counting in cutaneous malignant melanoma. A total of 457 consecutive cases of nodular cutaneous melanoma were initially included in this series. The mitotic count was assessed on hematoxylin and eosin sections, and PHH3 was then examined by immunohistochemistry on standard sections of paraffin-embedded tumor tissue. Both the mitotic count and the number of PHH3-stained mitotic figures were reco...
Using a high-throughput pyrosequencing technology, this study assessed bacterial community structure and time-scale variability in great detail in seven full-scale anaerobic digesters operated variously in terms of influent substrate, digestion temperature, and reactor configuration. Pyrosequencing generated a total of 83,774 sequence reads from 40 digester sludge samples collected monthly for six months. The highest number of sequence reads were detected within Proteobacteria (20.5%), followed by those within Bacteroidetes (19.7%), Firmicutes (17.8%), and Chloroflexi (4.8%). The relative composition of bacterial populations was varied within the digesters as well as between the digesters, and the bacterial community structures were mainly influenced by digestion temperature. Detailed bacterial community structures were assessed by analyzing the operational taxonomic units (OTUs) based on 97% sequence similarity, which resulted in a total of 9051 OTUs. Among these, a total of 31 core OTUs were analyzed and inferred phylogenetically, which enabled us to classify the sequences within an unclassified phylum. Unclassified sequences were mostly affiliated with the sequences within Spirochaetes and Firmicutes. Interestingly, numerically dominant novel phylotypes (18% of the total sequence reads) presumably involved in anaerobic digestion within Spirochaetes were identified. Temporal variability was further explored using a non-metric multidimensional scaling ordination which demonstrated that the variability of the bacterial community within the digesters was smaller than between digesters. Correlation analysis demonstrated that digester performance and operational conditions affected the pattern of bacterial community in the ordination. Additionally, a multi-response permutation procedure revealed that the bacterial communities within the digesters were more similar than those belonging to other digesters statistically, demonstrating a patchiness of the digesters in the distribution of bacterial populations. Overall, this study revealed the correlation of bacterial community structure and time-scale variability with digester performance and operating conditions. PMID:22426622
Evaluation of three portable samplers for monitoring airborne fungi
Airborne fungi were monitored at five sample sites with the Burkard portable, the RCS Plus, and the SAS Super 90 air samplers; the Andersen 2-stage impactor was used for comparison. All samplers were calibrated before being used simultaneously to collect 100-liter samples at each site. The Andersen and Burkard samplers retrieved equivalent volumes of airborne fungi; the SAS Super 90 and RCS Plus measurements did not differ from each other but were significantly lower than those obtained with the Andersen or Burkard samplers. Total fungal counts correlated linearly with Cladosporium and Penicillium counts. Alternaria species, although present at all sites, did not correlate with total count or with amounts of any other fungal genera. Sampler and location significantly influenced fungal counts, but no interactions between samplers and locations were found.
Lower white blood cell counts in elite athletes training for highly aerobic sports
White cell counts at rest might be lower in athletes participating in selected endurance-type sports. Here, we analysed blood tests of elite athletes collected over a 10-year period. Reference ranges were established for 14 female and 14 male sports involving 3,679 samples from 937 females and 4,654 samples from 1,310 males. Total white blood cell counts and counts of neutrophils, lymphocytes and monocytes were quantified. Each sport was scaled (1?5) for its perceived metabolic stress (aerobic?anaerobic) and mechanical stress (concentric?eccentric) by 13 sports physiologists. Substantially lower total white cell and neutrophil counts were observed in aerobic sports of cycling and triathlon (~16% of test results below the normal reference range) compared with team or skill-based sports such...
Mould Stachybotrys chartarum (Ehrenb.) Hughes is known to pose a health risk in indoor environments. Most of its strains can produce several intra- and extracellular trichothecene mycotoxins. Complex secondary metabolites of stachybotrys isolates from mouldy dwellings/public buildings in Slovakia were intratracheally instilled in Wistar male rats (4 microg in 0.2 mL of 0.2 % dimethylsulphoxide; diacetoxyscirpenol as the positive control). After three days, haematological parameters were measured in peripheral blood and inflammatory response biomarkers in bronchoalveolar lavage fluid (BALF), and the results were statistically analysed. Exometabolites proved to suppress red blood cell (RBC), decreasing the total RBC count, haemoglobin, and haematocrit. The exposed rats showed significantly higher total BALF cell count, indicating inflammation, lower alveolar macrophage counts, and increased granulocyte count related to the BALF cells. Due to haematotoxic and inflammation-inducing properties, metabolites of S. chartarum can cause damage to the airways and haematological disorders in occupants of mouldy buildings. PMID:20061240
Spatial distribution, diversity and composition of bacterial communities of the northern South China Sea (SCS) surface water and the relationship with the in situ environmental chemistry were investigated. Polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) was used to investigate the bacterial community structure. The DGGE gel showed that each sample harbored a distinct bacterial community structure and spatial variations of bacterial community composition among all samples were obviously. A total of 17 intensive bands were excised and the sequence analysis of these DGGE bands revealed that Proteobacteria were the dominant bacterial group of surface water in the north part of SCS. Results of the taxonomic analysis showed that the communities consisted of Proteobac...
Effects of commercial enzymes on the adhesion of a marine biofilm-forming bacterium.
The antifouling potential of commercial hydrolases, four proteases, seven glycosidases and one lipase was evaluated on the adhesion of marine Pseudoalteromonas sp. D41. The experimental method, adapted to screen antifouling agents, was based on bacterial adhesion in natural sterile sea water in a microtiter plate and on total biomass quantification by the fluorescent dye DAPI (4[prime]6-diamidino-2-phenylindole). Savinase (subtilisin) was the most effective hydrolase in both the prevention of bacterial adhesion and the removal of adhered bacteria. However, some enzymatic preparations tested such as Amano protease were not only ineffective but also increased the number of adhered bacterial cells. Enumeration using epifluorescence microscopy of CTC (5-cyano-2,3-ditolyl tetrazolium chloride) and DAPI stained adhered D41 cells confirmed these observations. Overall, these results demonstrated that hydrolases could either prevent adhesion and remove adhered bacterial cells effectively, or conversely increase bacterial adhesion, depending on enzymatic concentrations and the type of enzymes tested. PMID:18058451
High bacterial 16S rRNA gene diversity above the atmospheric boundary layer
The atmosphere is host to an omnipresent bacterial community that may influence fundamental atmospheric processes such as cloud formation and precipitation onset. Knowledge of this bacterial community is scarce, particularly in air masses relevant to cloud formation. Using a light aircraft, we sampled above the atmospheric boundary layer?that is, at heights at which cloud condensation occurs?over coastal areas of Sweden and Denmark in summer 2009. Enumeration indicated total bacterial numbers of 4??101 to 1.8??103?m?3 air and colony-forming units of 0?6?bacteria m?3 air. 16S rRNA gene libraries constructed from samples collected above the Baltic Sea coast revealed a highly diverse bacterial community dominated by species belonging to the genera Sphingomonas and Pseudomonas. Bacterial spe...
High bacterial 16S rRNA gene diversity above the atmospheric boundary layer
The atmosphere is host to an omnipresent bacterial community that may influence fundamental atmospheric processes such as cloud formation and precipitation onset. Knowledge of this bacterial community is scarce, particularly in air masses relevant to cloud formation. Using a light aircraft, we sampled above the atmospheric boundary layer?that is, at heights at which cloud condensation occurs?over coastal areas of Sweden and Denmark in summer 2009. Enumeration indicated total bacterial numbers of 4 × 101 to 1.8 × 103 m?3 air and colony-forming units of 0?6 bacteria m?3 air. 16S rRNA gene libraries constructed from samples collected above the Baltic Sea coast revealed a highly diverse bacterial community dominated by species belonging to the genera Sphingomonas and Pseudomonas. Bacterial spe...
The study examined and compared levels of aerial contamination in commercial beef and sheep plants at four sites, i.e. lairage, hide/fleece pulling, evisceration and chilling. Aerial contamination was determined by impaction and sedimentation onto Plate Count Agar to enumerate Total Viable Counts, MacConkey Agar to enumerate coliforms and Violate Red Bile Glucose Agar to enumerate Enterobacteriaceae. AS I cannot see any difference in the text here - I am not sure what the change is?. The levels of aerial contamination were similar at equivalent sites in beef and sheep plants, irrespective of the sampling method or the type of organisms recovered. Mean log counts recovered on each medium in the chillers were generally significantly lower (P < .05) than the corresponding mean log numbers recovered at the other three sites. The relationship between impaction (air) and sedimentation (surface) counts could be described by the surface to air ratio (SAR) which in this study had an R(2) of 0.77. Further studies in an experimental plant compared counts recovered from the neck of beef carcasses with aerial counts determined by impaction and sedimentation onto agar and irradiated meat pieces. A relationship between counts on beef carcasses and in the air could not be established, irrespective of the method used to compare counts. PMID:22986197
Prognostic importance of the mitotic marker phosphohistone H3 in cutaneous nodular melanoma.
Mitotic count is a known prognostic predictor in cutaneous melanoma, and is included in the current American Joint Committee on Cancer tumor-node-metastasis (TNM) staging system. The mitotic marker phosphohistone H3 (PHH3) is considered to facilitate counting of mitosis, and the purpose of this study was to evaluate the prognostic significance and strength of PHH3 in comparison with standard mitotic counting in cutaneous malignant melanoma. A total of 457 consecutive cases of nodular cutaneous melanoma were initially included in this series. The mitotic count was assessed on hematoxylin and eosin sections, and PHH3 was then examined by immunohistochemistry on standard sections of paraffin-embedded tumor tissue. Both the mitotic count and the number of PHH3-stained mitotic figures were recorded in a minimum area of 1 mm(2). Increased mitotic count and PHH3 value were both associated with unfavorable features like tumor thickness and presence of ulceration. Univariate survival analysis showed a highly significant prognostic impact of mitotic count and PHH3, whereas multivariate analysis indicated PHH3 to be a stronger prognostic indicator than mitotic count. Assessment of mitotic activity by PHH3 immunostaining might have important practical advantages, and should be further studied to consider a place in routine examination of all cutaneous melanomas. PMID:22297638
Association between serum cystatin C, monocytes and other inflammatory markers
Abstract Background:- Cystatin C is a marker of renal function that appears to be associated with inflammation. The aim of the present study was to investigate whether there is any relationship between cystatin C, total and differential leukocyte count and other inflammatory markers. Methods:- Cystatin C, creatinine, high sensitivity C-reactive protein (hs-CRP), haptoglobin, ferritin, serum albumin, glucose, total cholesterol, HDL and triglycerides together with total and differential leukocyte count were determined in 490 adults (46 16 years, 40% men) who underwent a typical health examination. Glomerular filtration rate was estimated by the simplified Modification of Diet in Renal Disease formula. Anthropometric and lifestyle characteristics were also recorded. Results:- After adjustment...
A 60-day experiment was carried out to study the effect of sub-lethal concentration of cypermethrin (1/10th of LC50) exposure on haematological and biochemical parameters of the Indian major carp, Catla catla fingerlings. Under exposure, the total erythrocyte count, total leucocyte count, haemoglobin content and haematocrit were decreased. All the studied serum parameters viz. total serum protein, albumin, globulin contents and albumin?globulin ratio were significantly decreased in cypermethrin-exposed fishes. A marked increase was recorded in alanine aminotransferase and aspartate aminotransferase activities in liver, whereas lactate dehydrogenase activity of muscle and acetylcholine esterase activity in brain were inhibited in cypermethrin-exposed fish. The membrane transport enzymes (to...
Acute and subchronic oral toxicities of Calendula officinalis extract in Wistar rats
We have studied the acute and subchronic oral toxicities of Calendula officinalis extract in male and female Wistar rats. A single acute C. officinalis extract dose of 2000mg/kg dissolved in distilled water was administered by oral gavage for acute toxicity. Subchronic doses of 50, 250 and 1000mg/kg/day were administered in drinking water. The major toxicological endpoints examined included animal body weight, water and food intake, selected tissue weights, and histopathological examinations. In addition, we examined blood elements: hematocrit, hemoglobin concentration, erythrocyte count, total and differential leukocyte count and blood clotting time and blood chemistry: glucose, total cholesterol, urea, total proteins, alkaline phosphatase, alanine aminotransferase (ALT) and aspartate ami...
Turkey vulture surveys in Cuba
Turkey Vultures (Cathartes aura), were surveyed monthly in Cuba from March 1982-January 1983. A total of 25371 vultures were tallied in 7186 km (3.5 vultures/transect km) of roadside counting along main highways leading from the city of La Habana (northwestern Cuba) to the city of Las Tunas (southeast). Numbers of vultures counted declined substantially beyond 200 m from the transect road. Density of vultures observed within 200 m of the road along the transect route was 0.06/ha. Highest counts were obtained in March, April and June. Turkey Vulture flying activity was greatest during the periods 0900-1200 H and 1400-1700 H.
Counting rates from the two 1-kg PNL/USC ultralow-background germanium detectors are [<=] 0.3 counts keV[sup -1] d[sup -1] between 6 and 9 keV and [proportional to] 2 counts keV[sup -1] d[sup -1] between 4 and 6 keV. These data show a significant short-time rate dependence due to blasting and other mining operations in the Homestake gold mine. The mean shift in the centroid of the gallium x-ray peak was about 50 eV over a total period of about 500 days, indicating adequate stability for a search for annual modulation of Cold Dark Matter (CDM) particles. (orig.).
HENC performance evaluation and plutonium calibration
The authors have designed a high-efficiency neutron counter (HENC) to increase the plutonium content in 200-L waste drums. The counter uses totals neutron counting, coincidence counting, and multiplicity counting to determine the plutonium mass. The HENC was developed as part of a Cooperative Research and Development Agreement between the Department of Energy and Canberra Industries. This report presents the results of the detector modifications, the performance tests, the add-a-source calibration, and the plutonium calibration at Los Alamos National Laboratory (TA-35) in 1996.
A collimated portable gamma-ray detector will be used to quantify the plutonium content of items that can be approximated as a point, line, or area geometry with respect to the detector. These items can include ducts, piping, glove boxes, isolated equipment inside of gloveboxes, and HEPA filters. The Generalized Geometry Holdup (GGH) model is used for the reduction of counting data. This document specifies the calculations to reduce counting data into contained plutonium and the associated total measurement uncertainty.
Interdecadal trend turning of global terrestrial temperature and precipitation during 1951-2002
A grid-by-grid counting of interdecadal trend turning (ITT) of annual mean surface air temperature (SAT) and total precipitation at 67,359 terrestrial grids in the period 1951-2002 is presented. An analysis of the last ITTs of SAT and total precipitation in the period, in the context of both occurre...
Microbiological contamination of pig and cattle carcasses in different small-scale Swiss abattoirs.
A total of 750 pig carcasses and 535 cattle carcasses from 17 small-scale abattoirs were sampled by excision at four sites (pig: neck, belly, back, ham; cattle: neck, brisket, flank, rump). Samples were examined for total viable counts (TVC) and Enterobacteriaceae. Mean TVCs ranged from 2.4 to 4.2 l...
11 pages, 1 figure, 5 tables. | A total of 7460 prey items were counted in the 199 pellets analysed, of which 96.2% corresponded to arthropods. Aeshnidae larvae (Odonata) made up 66.1% of total prey items and were the main invertebrate group. Vertebrates constituted 3.8%, while reptiles and mammals ...
Adhesion and biocides inactivation of Salmonella on stainless steel and polyethylene
Abstract in english The adhesion of Salmonella (S.) strains to stainless steel and polyethylene and their inactivation by biocides used in food industry was investigated. Coupons of stainless steel and polyethylene were immersed in bacterial suspensions of S. Enteritidis, S. Typhimurium, and S. Bredeney during 15, 30, and 60 minutes, and submitted to different concentrations of peracetic acid (PAA), sodium hypochlorite (NaOCl), and quaternary ammonium (Quat) sanitizers. Hydrophobicity of the (more) surfaces was evaluated by contact angle measurements using the sessile drop method and bacterial adhesion was accompanied through bacterial counts and scanning electron microscopy (SEM). Results indicated that the three serovars of Salmonella presented similar adhesion to both materials (5.0 to 6.5 log cfu cm-2). The time of exposure did not influence the counts of adhered cells on both surfaces, however SEM revealed larger clusters of S. Enteritidis on both materials, not found for the other serovars. S. Enteritidis presented lower sessile drop angle on polyethylene, indicating hydrophilic properties of this material. The biocides were not able to inactivate all the microorganisms adhered on both surfaces. At least 1 log cfu cm-2 of all serovars tested remained viable after the exposure to different biocide concentrations. In general, higher counts of survivors were observed on polyethylene disinfected with different concentrations of biocides. S. Bredeney e S. Typhimurium were more resistant than S. Enteritidis to PAA, whilst S. Enteritidis presented smaller reduction rates to NaOCl. This last biocide was able to reduce Salmonella counts in approximately 3.0 to 4.0 log cm-2. When adhered to polyethylene, the serovars S. Typhimurium and S. Enteritidis were more resistant to Quat than S. Bredeney in all concentrations tested, and the numbers of S. Enteritidis remained almost unaltered. On stainless steel disinfected by Quat, S. Bredeney presented higher numbers of survivors.
Abstract Objective: The aim of this study was to evaluate the bactericidal effects of Nd:YAG laser on biofilm of Enterococcus faecalis. Background data: It is difficult to eliminate bacterial biofilms with routine endodontic preparation techniques. It might be possible to eliminate biofilms remaining in the root canals of teeth with lasers. Materials and methods: The root canals of 60 extracted teeth were prepared and E. faecalis biofilms were formed within the root canals. Then the teeth were randomly divided into four groups of 15. Group 1 samples did not undergo any interventions, to serve as controls. Group 2 samples underwent a 3-W laser beam for 10?sec. The root canals in group 3 were irrigated with 1% sodium hypochlorite for 15?min and then irradiated with a 3-W laser beam for 10?sec. The root canals in group 4 were irrigated with 1% sodium hypochlorite for 15?min. Dentin chips were collected from the root canal walls and weighed. Then the chips were used to prepare a suspension. The classic colony-forming unit (CFU) counting technique was used to determine remaining bacterial counts. Results: The bacterial counts in groups 2 and 4 had decreased to 54% and 2.39% of the control group, respectively. In group 3 no bacterial growth was observed. There were no significant differences between groups 1 and 2 (p>0.05). Conclusions: Based on the results of the present study, the effect of Nd:YAG laser beam on E. faecalis biofilm is less than that of sodium hypochlorite solution. A combination of laser and sodium hypochlorite results in complete elimination of E. faecalis biofilm. PMID:23003122
The effect of gamma radiation on moisture content, total mold counts, Aspergillus counts, and aflatoxins of three hot pepper hybrids (Sky Red, Maha, and Wonder King) was investigated. Whole dried peppers packed in polyethylene bags were gamma irradiated at 0 (control), 2, 4, and 6 kGy and stored at 25°C for 90 days. Gamma radiation proved to be effective in reducing total mold and Aspergillus counts in a dose-dependent relationship. Total mold counts in irradiated peppers immediately after treatments were significantly lowered compared with those in nonirradiated samples, achieving 90 and 99% reduction at 2- and 4-kGy doses, respectively. Aspergillus counts were significantly reduced, by 93 and 97%, immediately after irradiation at doses of 2 and 4 kGy, respectively. A radiation dose of 6 kGy completely eliminated the population of total molds and Aspergillus fungi. The evolution of total molds in control and irradiated samples indicated no further fungal proliferation during 3 months of storage at 25°C. Aflatoxin levels were slightly affected by radiation doses of 2 and 4 kGy and showed a nonsignificant reduction of 6% at the highest radiation dose of 6 kGy. The distinct effectiveness of gamma radiation in molds and aflatoxins can be explained by the target theory of food irradiation, which states that the likelihood of a microorganism or a molecule being inactivated by gamma rays increases as its size increases. PMID:22856582
