Bacterial Contamination Of Water Research Articles

Bacteriological studies of the water, soil and plants of the wetland near Olsztyn

This manuscript presents the results of investigations into the degree of bacterial contamination of water, soil, submerged in water and aerial leaves and stems of sedge (Carex acutiformis) as well as dead and live roots of this plant. Analyses were carried out in 2 subsequent annual cycles (in 1993 and 1994) in the area of one of greater wetlands located in the vicinity of the Stary Dwor forester’s lodge near Olsztyn. Water was examined at 3 stations, whereas soil and plants at 2 stations. In most of the water samples, the total bacteria count on broth agar at a temp. of 22°C and 37°C was within the range specifi ed for pure and/or negligibly contaminated waters. The number of coli group bacteria and that of fecal coli group bacteria was also within the range accepted for waters, in most of the samples, and was classifi ed as having a “very good” and “good” purity state. On the submerged and aerial parts of sedge as well as its roots, higher numbers were reported only for bacteria determined on broth agar at a temp. of 22°C. The numbers of bacteria determined on broth agar at a temp. of 37°C and bacteria indicative of the sanitary state did not exceed 4.4 × 105 CFU·GDW-1 and 126–263 MPN· GDW-1, respectively. In soil of the root system of sedge, the numbers of bacteria determined on broth agar at a temp. of 22°C and 37°C, and those of bacteria indicative of the sanitary state, reached higher values only sporadically. The latter often were not determined in the soil mass examined. The same tendency refers also to the numbers of the examined groups of indicative bacteria in young (the current year’s) and older (the previous year’s) roots of sedge. Often, higher numbers of the bacteria indicative of contamination degree and sanitary state in water, soil and particular fragments of lesser pond sedge occurred during or after spring thaw and in the summer after stormy precipitation, and less frequently in the autumn.

Detection of E. coli in water using semi-conducting polymeric thin film sensor

This paper describes the application of semi-conducting polyaniline doped with Fe–Al vacuum deposited thin film as a sensor for the determination of Escherichia coli ( E. coli) cells in the liquid medium. The presence of E. coli as a bacterial contamination in water was detected based on a change in conductivity due to redox reaction at the film surface.

Evaluation of Hygiene and Safety Controls for On-Line Paired Hemodiafiltration (PHF)

On-line hemodiafiltration is gaining popularity due to increasing evidence of clinical benefits however it also requires strict attention to hygiene and safety as notable quantities of liquid are reinfused into the patient. Although most centers are improving their attention to water quality, a frequent concern is the inadvertent or accidental contamination of water and whether the redundant safety controls are sufficient to protect the patient. In the present study, in order to simulate a worst-case safety condition, we tested in vitro the reliability of paired hemodiafiltration - (PHF), under low, moderate and high bacterial contamination of the water supply. Tests were performed using various bacterial concentrations (range 85-2000 cfu/mL) of Pseudomonas Aeruginosa. Samples were analyzed from different sites throughout the entire on-line hemodiafiltration circuit for bacteria endotoxin, fungus and ability to stimulate whole blood production of TNFalfa. In the in vitro contamination study, with the three bacterial concentrations tested at various points of the circuit, bacteria were below the level of detection and endotoxins were < 0.01 UE/mL. Addition of dialysate samples taken after the first stage of microfiltration, as well as after the first and second stage of ultrafiltration and incubated with whole blood were not associated with stimulated production of TNFalfa . PHF appeared to be a safe and feasible method for on-line hemodiafiltration even in the unforeseen presence of bacterial contamination of the feed water or water distribution system.

A simple method for assessing leaching risk of bacteria through soils

Abstract. Bacterial contamination of water is a problem worldwide and is often acute in developing countries where human and animal waste is disposed of on land for use as fertilizer or because of poorly developed sanitation systems. Studying leaching risk through soils is difficult when no suitable microbiological laboratory is available. A method using the movement of ZnO particles through soils as a surrogate for studying bacteria directly was tested. ZnO particles with a similar size to bacteria can readily be detected by chemical analysis. For a range of nine different soil textures, leaching rates of ZnO particles under near saturated conditions were significantly correlated with leaching rates of Escherichia coli cells (P=0.013). For both ZnO and E. coli, leaching was generally greatest through fine textured soils.

Toxicology Review and Risk Assessment of Resorcinol: Thyroid Effects

Resorcinol administered at high doses to rodents can disrupt thyroid hormone synthesis and can produce goitrogenic effects. These effects were not seen in a 2-year bioassay at doses of up to 520 mg/kg/day. There are species-specific differences in synthesis, binding, and transport of thyroid hormone that complicate interpretation of goitrogenesis in rodents. Clinical case reports from patients undergoing resorcinol therapy for dermatological indications reveal thyroid side effects when copious amounts of resorcinol-containing ointments are applied to integrity-compromised skin for months to years. Effect levels were greater than 34 mg/kg/day. Occupational epidemiology studies provide no evidence that exposure to resorcinol at levels greater than found in the general environment causes thyroid dysfunction. Studies investigating the relationship between endemic goiter and exposure to “phenolics,” including resorcinol, in drinking water do not fulfill accepted scientific criteria for establishing resorcinol as a cause of thyroid disease. Those reports neither quantify exposure levels nor demonstrate dose–response relationships or rule out confounding by the multiple other chemicals present in water supplies, by bacterial contamination of water, or by nutritional factors. A risk assessment comparing potential worst-case exposures to resorcinol through its use in dermatological preparations supports the conclusion that under real-world conditions, human exposures to resorcinol are not expected to cause adverse effects on thyroid function.

Effects of ozone treatment on cell growth and ultrastructural changes in bacteria.

Ozone appeared to inhibit growth and caused the death of gram negative and gram positive tested bacteria: Escherichia coli, Salmonella sp., Staphylococcus aureus and Bacillus subtilis. Bacterial cultures at 10(3), 10(4), 10(5), 10(6), and 10(7) cfu/ml dilution were exposed to 0.167/mg/min/L of ozone at different time intervals (0, 5, 10, 15, 30, 60, 90, 120, and 150 min). Cell viability was observed in all types of tested bacteria at 10(3), 10(4), 10(3) cfu/ml within 30 min after ozone exposure. However, cell inactivation was not significantly observed at concentrations of 10(6), 10(7) cfu/ml even after an exposure of 150 min. Ultrastructural changes of treated bacteria showed deformation, rough damage and surface destruction revealed by scanning electron microscopy. Some bacterial cells showed collapsed and shrunken patterns within 60 min and severe rupture and cellular lysis after 90 min of ozone treatment. This study supports the proposed mechanism of the bacteria inactivation by ozone that caused cell membrane destruction and finally lysis reaction. Thus, the precaution of using ozone as a biocide should be used to address appropriate concentrations of bacterial contamination in water.

Eau et Santé - L'eau polluée le plus grand fléau du monde

WHO estimates that about 20 million people die in the world, each year, due to drinking water-related diseases. The absence of safe water and sanitation, specially in developping countries plays a major part in this tragedy. Bacteriological analysis of 1700 water points in West Africa revealed that 100% of ponds, 70% of rural wells, 15% of concrete-lined wells and 7% of boreholes, contain water unsafe for human consumption. So installation of boreholes, found to be the best safeguard against the bacterial contamination of water, has to be developed in African rural areas. However, from boreholes to consumer, safe drinking water usually becomes polluted with foecal bacteria during transport and storage. For bacteriological decontamination, sterilisation in the UV or by the use of traditional filters has been proposed and affords no guarantee for the health of the consumer. In contrast chlorination represents a final option for the purification of drinking water associated with improved environmental sanitation. Finally carefully planned health education is of fundamental importance within the context of rural hydraulic programmes having the power to mobilise the population for the promotion of safe drinking water improving health and greater well-being.

Bacterial contamination in water of the River Ganga and its risk to human health

Water of the River Ganga is extensively used for drinking, bathing and cleaning purposes. Bacterial analysis of Ganga water was carried out at three different sites in Bhagalpur town which discharges untreated municipal and industrial effluents in river at various points. Total bacterial density (TBD), total coliform (TC), faecal coliform (FC), faecal streptococci (FS), Escherichia coli and Clostridium perfringens were substantially high and much beyond the permissible limit of ISI and WHO. There was a marked correlation between physico-chemical quality of water and bacterial density. The presence of Actinomyces sp., Aerobacter aerogenes, A. Cloacae, Micrococcus sp., Salmonella sp., Staphylococcus aureus, Bacillus sp. and Shigella sp. indicated the level of faecal contamination in water. Hence, direct consumption of untreated Ganga water and bathing in this stretch poses a great health risk.

Bacterial succession within a biofilm in water supply lines of dental air–water syringes

Biofilms have been implicated as reservoirs for bacterial contamination of water delivered by dental air-water syringes. A 6-month study was done of bacterial colonization and biofilm formation in plastic water supply lines connected to dental air-water syringes. Changes in biofilm flora were observed by both scanning electron microscopy and bacteriologic culture. By day 7, many rod- and spiral-shaped bacteria had colonized the ridged surface of the luminal wall of the tubing, as revealed by scanning electron microscopy. By day 30, individual microcolonies were embedded in extracellular polymeric material. By day 120, these microcolonies had begun to coalesce, and by day 180 the biofilm had developed into a multilayered, heterogeneous mixture of microcolonies. The mean aerobic plate counts of colony-forming units of planktonic and biofilm populations were, in log10 values, 5.9 +/- 0.54/mL and 4.2 +/- 0.82/cm2, respectively. Early colonizers were predominantly Pseudomonas spp., but included Pasteurella, Moraxella, Ochrobactrum, and Aeromonas spp. Flavobacterium and Acinetobacter spp. were observed later. Many of these organisms are opportunistic pathogens. These results demonstrate the longitudinal dynamics of biofilm formation.

Hydraulique rurale et santé

Click to increase image sizeClick to decrease image sizeWHO estimates that about 20 million people die in the world each year due to drinking water-related diseases. The absence of safe water and sanitation specially in developing countries plays a major part in this tragedy. Bacteriological analysis of 1 700 water points in West Africa revealed that 100 % of ponds, 70 % of rural wells, 15 % of concrete-lined wells and 7 % of boreholes contain water unsafe for human consumption. So, installation of boreholes, found to be the best safeguard against the bacterial contamination of water, has to be developped in African rural areas. However, from boreholes to consumer, safe drinking water usually becomes polluted with faecal bacteria during transport and storage. For bacteriological decontamination, sterilisation in the UV or by the use of traditional filters has been proposed and affords no guarantee for the health of the consumer. ln contrast, chlorinalion represents a final option for the purification of drinking water associated with improved environmental sanitation. Finally, carefully planned health education is of fundamental importance within the context of rural hydraulic programmes having the power to mobilise the population for the promotion of safe drinking water improving health and greater well-being.

Bacteriology of hemodialysis fluids: are current methodologies meaningful?

Reports of increasing endotoxic reactions in dialysis centers using high-flux dialyzers and high contamination in liquid bicarbonate concentrates have resulted in concern for the microbial contamination of dialysate. The influence of salt-supplemented media on the recovery of bacterial contaminants from the fluids used in hemodialysis has been examined. This study found a negative influence of a 2% NaCl supplementation of growth media for both purified water and dialysate. Salt-supplemented pour plate cultures of bicarbonate concentrate samples were not statistically different from nonsupplemented cultures (p = 0.2). The influence of the bicarbonate salt on recovery in the pour plates was not addressed. The different media recommended for monitoring microbial contamination of dialysis fluids were compared. As previously reported, both water and dialysate collected from a relatively large geographic area showed higher recoveries on Reasoner's R2A agar than on media recommended by the Association for Advancement of Medical Instrumentation (AAMI) standards (p < 0.0001). Standard methods agar (SMA) and trypticase soy agar (TSA) produced the next highest recovery for water and dialysate, respectively. The higher recoveries generally observed on R2A or SMA suggest that to provide better patient safety these media should be selected for monitoring bacterial contamination of water, and R2A, SMA, or TSA for dialysate. The variability in the species identified across the three fluids and variability in counts observed in the different fluids suggest that significant dialysate contamination may occur from sources other than the water and bicarbonate concentrates.

Uptake and Elimination of Coliform Bacteria by Four Marine Bivalve Mollusks

Bivalve filter feeding mollusks remove suspended bacteria from the ambient water and either sediment them with the pseudofaeces, or ingest and digest them. On the basis of bacterial contamination of water and known pumping rate, accumulations usually exceed expected levels by an order of magnitude. This does not reflect high uptake efficiency of the bivalve, but is a function of the digestive process separating bacterial clusters, thereby increasing inoculative loci both for multiple tube estimates and plate counts. Uptake rates are species specific and temperature dependent and show little correlation with the ambient bacterial loading. Elimination is also species specific and variable.

Prevention of bacterial contamination of water in dental units

A study of the bacterial contamination of water in dental units was conducted in five dental practitioners' clinics and one university dental hospital in Tokyo. Various bacteria in numbers of 10(2)-10(5)/ml were detected in the water delivered from all 42 of the dental units examined, though very few bacteria were detected in the tap water upstream of the units. Most of the organisms isolated from the water were Gram-negative bacilli, predominantly Alcaligenes, Achromobacter and Pseudomonas spp. A new decontamination apparatus that could be incorporated into the pipe system of dental units was devised and its performance was evaluated in one unit. It effectively prevented bacterial contamination of the water.

Bacterial contamination of dental handpieces : Kellett M. and Holbrook W. P. J. Dent. 8 (1980) 249–253

Bacterial contamination of water- and air-lines was investigated after artificial contamination and clinical use of dental handpieces. The effect of lubrication, disinfection and autoclaving on this contamination was also addressed. Bacterial growth was recorded in both the air- and water-lines during clinical and artificial contamination, with water-lines showing heavier contamination than air-lines. External and internal surfaces of handpieces still yielded bacterial growth after lubrication and disinfection, while heat sterilisation (autoclaving) rendered both internal and external surfaces sterile.

Studies on dental aerobiology. IV. Bacterial contamination of water delivered by dental units.

Water sprays from a dental handpiece and air-water syringe were evaluated for bacterial content. Bacterial concentrations that far exceeded limits permissible for public water supplies were observed. A simple method for reducing bacterial contamination in water lines for dental equipment is presented.