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PubMed2004

Heavy metal contamination of water, soil and produce within riverine communities of the Río Pilcomayo basin, Bolivia.

The Río Pilcomayo heads on the Cerro Rico de Potosí precious metal-polymetallic tin deposits of Southern Bolivia. Mining of the Potosí deposits began in 1545 and has led to the severe contamination of the Pilcomayo's water and sediments for at least 200 km downstream of the mines. This investigation addresses the potential human health affects of metal and As contamination on four communities located along the upper Río Pilcomayo by examining the potential significance of human exposure pathways associated with soils, crops and water (including river, irrigation and drinking water supplies). The most significantly contaminated agricultural soils occur upstream at Mondragón where Cd, Pb and Zn concentrations exceed recommended guideline values for agricultural use. Further downstream the degree of contamination decreases, and metal concentrations are below Dutch, German and Canadian guideline values. Metal and As concentrations in agricultural products from the four communities were generally below existing guidelines for heavy metal content in commercially-sold vegetables. Thus, the consumption of contaminated produce does not appear to represent a significant exposure pathway. A possible exception is Pb in carrots, lettuce and beetroots from Sotomayor and Tuero Chico; 37% and 55% of the samples, respectively, exceeded recommended guidelines. Most communities obtain drinking water from sources other than the Río Pilcomayo. In general, dissolved concentrations of metals and As in drinking water from the four studied communities are below the WHO guideline values with the exception of Sb, which was high at Tasapampa. The inadvertent ingestion of contaminated water from irrigation canals and the Río Pilcomayo represents a potential exposure pathway, but its significance is thought to be minimal. Given the degree of soil contamination in the area, perhaps the most significant exposure pathway is the ingestion of contaminated soil particles, particularly particles attached to, and consumed with vegetables. The risks associated with this pathway can be reduced by thoroughly washing or peeling the vegetables prior to consumption. Other exposure pathways that are currently under investigation include the consumption of contaminated meat from livestock and poultry, which drink polluted waters and the ingestion of contaminated wind-blown dust.

Agriculture↗

PubMed2004

Human exposure to contaminants in the traditional Greenland diet.

The traditional diet is a significant source of contaminants to people in Greenland, although contaminant levels vary widely among species and tissue from very low in many to very high in a few. Our study has included cadmium, mercury, selenium, polychlorinated biphenyls (PCB), dichlorophenyltrichloroethane (DDT), chlordane, hexachlorocyclohexanes (HCH), chlorobenzenes, dieldrin and toxaphene in the major species and tissues consumed by Greenlanders. In general, the levels of these are very low in terrestrial species and in muscle of many marine species. High organochlorines concentrations are typically found in blubber of marine mammals and high metal levels in liver and kidney of seals and whales. In this study, the mean intakes of cadmium, chlordanes and toxaphene significantly exceed 'acceptable/tolerable intakes' (ADI/TDI) by a factor between 2.5 and 6. Mean intakes of mercury, PCB and dieldrin also exceed ADI/TDI by up to approximately 50%. However as these figures are mean intakes and as variation in both food intake and contaminant levels is large, the variation of contaminant intake among individuals is also large, and some individuals will be exposed to significantly higher intakes. The mean intakes of DDT, HCH and chlorobenzenes are well below the ADI/TDI values, and it seems unlikely that the TDI for these contaminants normally is exceeded in the Greenland population. The evaluation of contaminant intake in this study points to seal muscle, seal liver, seal kidney, seal blubber and whale blubber as the dominant contributors of contaminants in the traditional diet. Levels in liver from Greenland halibut, snow crab, king eider, kittiwake, beluga and narwhal and kidney of beluga and narwhal are also high but were, with the exception of toxaphene in Greenland halibut liver, not important sources in this study, because they were eaten in low quantities. A way to minimize contaminant intake would be to avoid or limit the consumption of diet items with high contaminant levels. If we assume a traditional diet composition in this study without fish liver, bird liver, seal liver, seal kidney, seal blubber, whale liver, whale kidney and whale blubber, the intake of all contaminants would be below the TDIs for these. This will result in a reduction of the intake of the amount of traditional food of only 24-25%, and it is not likely that this changed diet will result in deficiency of minerals, vitamins or other nutritional compounds.

Adolescent↗

PubMed1998

Potential for cross-contamination from use of a needleless injector.

BACKGROUND: Medical devices that are used on patients in fields containing potentially infectious body fluids can become contaminated and transmit infectious agents to other sites on the patient or to other patients if the devices are not properly cleaned and decontaminated after use on each patient treatment site. One such device is the needleless or jet injector, which is widely used in medicine and dentistry to deliver local anesthetic in procedures such as bone marrow aspirations, lumbar punctures, and cutaneous and intraoral injections. This study was conducted to determine whether cross-contamination can occur on in vitro reuse of a needleless injector and whether a manufacturer's recommended method of injector decontamination (ie, immersion sterilization) is effective in the prevention of cross-contamination. METHODS: The study was performed with new autoclaved injectors, fluorescein dye, and Streptococcus crista (the bacteria commonly found in saliva) in the field of use to determine whether these devices can become contaminated during use and carry over the contamination to other sites during immediate reuse. RESULTS: Fluorescein dye and bacteria tests with the needleless injectors showed that contamination or carryover does occur. It appeared to reduced to a minimum when a autoclaved, sterile rubber cap used over the head of the device during injection was replaced between each use, although replacement of the rubber cap alone did not prevent carryover. Immersion of the head of the injector in a 2% glutaraldehyde solution for 30 minutes followed by a sterile water rinse and the replacement of the rubber cap with a sterile cap between uses was shown to curtail bacterial growth and prevent cross-contamination on immediate reuse of the device. CONCLUSION: This study demonstrated that needleless injectors become contaminated during in vitro use and direct contact with contaminated surfaces and that needless injectors carry over the contamination to subsequent sites of release. The replacement of the injector's rubber cap with a new one after initial discharge or the removal of an exposed rubber cap and immersion of the head of the injector in 2% glutaraldehyde followed by a rinse of the head in sterile water, as recommended by one injector manufacturer, can minimize or eliminate the carryover.

Contrast Media↗

PubMed1997

Possible implication of sterile connecting device in contamination of pooled platelet concentrates.

Considering the possibility that a pooled random donor platelet concentrate could become contaminated by welding with a sterile connecting device, we undertook a study to determine the influence of pooling on the contamination rate. As a control group, apheresis platelets were examined. Bacteriological testing was done with a sensitive CO2 detecting culture system, the BacT/ Alert. Out of 1105 pooled platelet concentrates prepared by the buffy coat method, 15 (1.4%) were confirmed as contaminated, all with Staphylococcus epidermidis and two with a second bacterial species, i.e. Staphylococcus capitis and Propionibacterium acnes, respectively. Median detection time by the BacT/Alert was 23 h. Twelve pools of five units were contaminated, which is significantly more than the three contaminated pools of four units. On the other hand, the reuse of the welding wafers proved not be a risk factor for contamination. One welded tubing segment of a contaminated platelet concentrate failed the air leakage test, an incident which was 73 times more frequent than with the sterile platelet concentrates. We found five pooled platelet concentrates containing Staphylococci from which no bacteria could be grown from the individual buffy coats that had been pooled. We suggest the contamination here to have occurred after separation of the buffy coat from the whole blood, possibly during the welding process. Finally, none out of 378 apheresis platelet concentrates was contaminated. All our observations highlight the potential risk for contamination when making pooled platelet concentrates with a sterile connecting device. For this type of transfusion product, we advocate bacteriological screening of all units before release. The incubation time for the sterility test should, however, be limited to 36 h, if logistical problems with the availability of platelets are to be avoided.

Automation↗

PubMed1997

Distribution and sources of microbial contamination on beef carcasses.

Three beef dressing lines of different capacity (160, 440 and 800 head d(-1)) were investigated with respect to contamination associated with carcass/hide and carcass/faeces contacts, the distribution of microbial contamination on carcasses and the antimicrobial efficacy of cold water carcass washes. Swab samples were taken from up to 17 sites for determination of Aerobic Plate Counts at 37 degrees C (APC 37 degrees C) and Escherichia coli enumeration using the Petrifilm procedure. The three beef dressing systems produced virtually identical patterns of microbial contamination. High contamination was found at those sites associated with opening cuts and/or subject to hide contact during hide removal. Where contamination is intermittent, the use of mean microbial data tended to obscure evidence of faecal or hide contact. Consequently, worst-case results, as represented by the 95th percentile value, were used to identify probable instances and sources of contact contamination. Sites not subject to faecal contamination or hide contact typically had swab sample APC (37 degrees C) values of less than log 2.00 cfu cm(-2) accompanied by the occasional detection of E. coli at levels below log 1.00 cfu cm(-2). Sites contacted by 'clean' hide typically had APC (37 degrees C) counts of log 3.00 cfu cm(-2) or greater accompanied by occasional E. coli counts not exceeding log 2.00 cfu cm(-2). Sites contaminated by direct faecal contact or contact with faecally contaminated hides typically had APC (37 degrees C) counts equal to, or greater than, log 4.00 cfu cm(-2) accompanied by E. coli counts exceeding log 2.00 cfu cm(-2). Cold water carcass washing was ineffective in removing microbial contamination and tended to bring about a posterior to anterior redistribution, resulting in increased counts at forequarter sites.

Abattoirs↗

PubMed2003

Cross-contamination with Salmonella on a broiler slaughterhouse line demonstrated by use of epidemiological markers.

AIMS: To investigate contamination of surfaces on a poultry slaughter line from infected poultry and subsequent cross-contamination of non-infected poultry. METHODS AND RESULTS: A broiler slaughterhouse was investigated for the presence of Salmonella on 17 defined points over two 1-week periods. Flocks supplied to slaughter and neck skin samples from processed chicken were likewise investigated. Salmonella was detected in 10 out of 18 flocks at ante-mortem inspection, while seven flocks tested positive in the finished products. Equipment at all but one control point at the slaughter line tested positive at least once during the study. The chicken receiving area was the most contaminated. By comparison of typing results from serotyping, plasmid profile typing and phage typing, direct evidence for cross-contamination with Salm. serotype Typhimurium, Salm. Serotype 4.12:b:- and Salm. serotype Virchow on the slaughter line was obtained for four of the flocks. The cleaning procedure in place did not remove all Salmonella from the contaminated areas. CONCLUSIONS: Evidence for contamination of equipment on a slaughter line and subsequent cross-contamination to non-infected chicken was provided by typing methods. SIGNIFICANCE AND IMPACT OF THE STUDY: This study has provided detailed information on cross-contamination on a slaughter line by the use of phage typing and plasmid profiling. The study stresses the importance of controlling Salmonella in the primary production, as contamination of the equipment on the slaughter line will act as a vehicle to contaminate finished products. Cleaning procedures on slaughter lines cannot be expected to control this problem with the current equipment.

Abattoirs↗

PubMed1999

Parenteral infusions bacterial contamination in a multi-institutional survey in Mexico: considerations for nosocomial mortality.

BACKGROUND: Parenteral infusions can be contaminated during administration (extrinsic contamination). A previous survey found that extrinsic contamination was not uncommon in a hospital in Mexico with lapses in aseptic techniques. To determine whether this problem exists in other similar institutions, we undertook a multi-institutional study. METHODS: We surveyed 6 hospitals (A to F) lacking an infection control committee to determine the level of extrinsic contamination. We visited each hospital and obtained samples of all the parenteral infusions in use, drawing 0.5-1 mL from the tubing injection port. Quantitative and qualitative bacterial cultures were performed. Chlorine levels of the tap water were measured. Visits were repeated until the survey was completed. RESULTS: A total of 751 infusions were cultured, of which 16 (2.13%) were contaminated. Hospital contamination rates varied from zero to 5.56%. Klebsiella pneumoniae was the most common isolate (10 cases). During the first sampling day in hospital C, the 7 infusions from the pediatric ward were found to be contaminated with a similar K pneumoniae strain. In-service education was started in this hospital. Infusion contamination was eliminated followed by a reduction in mortality rate. Overall, a higher risk for infusion contamination was noted for pediatric patients (P =.01, odds ratio = 3.28, 95% CI, 1.10-9.91) and in wards with inadequate water chlorine levels (P =. 02, odds ratio = 3.64, 95% CI, 1.08-13.51). CONCLUSIONS: If the hospitals surveyed are representative of others in developing countries, an endemic level of parenteral infusion contamination could exist in many hospitals throughout the world.

Adult↗

PubMed2003

Microbial contamination of cellular products for hematolymphoid transplantation therapy: assessment of the problem and strategies to minimize the clinical impact.

BACKGROUND: Hematopoietic progenitor stem cells (HPSC) are a specialized transfusion product used for transplantation. Microbial contamination may occur during harvest or subsequent manipulation of these cells. The same difficulties in ensuring a safe, sterile, final product are faced in the preparation of other cell-therapy products directly obtained from donors. Detection of contamination is problematic, and the clinical significance of infusing contaminated HPSC is controversial. METHODS: Chimeric Therapies' manufacturing and clinical experience with BM HPSC products and validation of a culture method for detection are described. In addition, this paper reviews the literature concerning contaminated blood products, including rates and circumstances of contamination, organisms, methods of detection, and the clinical significance of infusion of contaminated products. RESULTS: Seven of 33 BM harvest products received at Chimeric Therapies were culture positive for skin commensal organisms. Three of seven were culture positive in the infused product. This compares with literature reports of 0-42%. No patients had significant infusion reactions or evidence of infection related to the contamination. DISCUSSION: The risks associated with microbial contamination with skin commensals are insignificant compared with other components of transplantation. Contamination with pathogens can be eliminated with careful good manufacturing practices (GMP). A series of practical recommendations are presented for the reduction of contamination in HPSC and cell-therapy products.

Cell Culture Techniques↗

PubMed2005

Surface contamination of chemotherapy drug vials and evaluation of new vial-cleaning techniques: results of three studies.

PURPOSE: The results of three studies that describe the external contamination of chemotherapy drug vials are presented. New techniques for the improved decontamination of vials containing cisplatin are also described. SUMMARY: Study 1 evaluated the external contamination of drug vials with cyclophosphamide and ifosfamide in a pharmacy setting. Widespread contamination of the outside of drug vials was found with each drug. Study 2 evaluated the surface contamination of drug vials with cyclophosphamide and fluorouracil in three pharmacies. Sporadic contamination with fluorouracil was detected, while cyclophosphamide was found on most vials. In study 3, investigators compared the decontamination abilities of a standard decontamination procedure at the manufacturer level with an improved decontamination procedure and the use of sleeves to further decrease contamination. Though the methods of each study reported herein differed, the outcomes were similar. All chemotherapy drug vials studied demonstrated levels of contamination with the drug well above the limit of detection. Improved decontamination procedures, combined with the use of protective sleeves, reduced the level of platinum contamination by 90%, suggesting that standard decontamination procedures should be reconsidered. CONCLUSION: The results of these studies are consistent with several others that have reported contamination of the outside surface of drug vials for a number of chemotherapy drugs. Contamination can be reduced by using decontamination equipment and protective sleeves during the manufacturing process.

Antineoplastic Agents↗

PubMed2005

Effects of feeding blends of grains naturally contaminated with Fusarium mycotoxins on performance, metabolism, hematology, and immunocompetence of ducklings.

Experiments were conducted to determine the effects of feeding grains naturally contaminated with Fusarium mycotoxins on performance, metabolism, hematology, and immune competence of ducklings. Four hundred sixty-four 1-d-old White Pekin male ducklings were fed starter (0 to 2 wk), grower (3 to 4 wk), and finisher (5 to 6 wk) diets formulated with uncontaminated grains, a low level of contaminated grains, a high level of contaminated grains, or the higher level of contaminated grains + 0.2% polymeric glucomannan mycotoxin adsorbent. Body weight gains, feed consumption, and feed efficiency were not affected by diet. However, consumption of contaminated grains decreased plasma calcium concentrations after 2 wk and plasma uric acid concentrations at the 4-wk assessment point. Mean corpuscular hemoglobin concentrations and hematocrit decreased when ducks were fed contaminated grains for 4 or 6 wk, respectively. In contrast, total numbers of white blood cells and lymphocytes increased transiently in birds fed contaminated grains for 4 wk. The antibody response to sheep red blood cells (CD4+ T cell dependent) and the cell-mediated response to phytohemagglutinin-P (also CD4+ T cell dependent) were not affected by diet, but consumption of contaminated grains for 6 wk decreased the duration of peak cell-mediated response to dinitrochlorobenzene (CD8+ T cell dependent) assessed in a skin test. Feeding grains naturally contaminated with Fusarium mycotoxins, even at levels widely regarded as high, exerted only minor adverse effects on plasma chemistry and hematology of ducklings, and production parameters were unaffected in this avian species. Mycotoxin-contaminated feeds may, however, render these animals susceptible to infectious agents such as viruses against which the CD8+ T cell provides necessary defence. Glucomannan mycotoxin adsorbent was not effective in preventing alterations caused by Fusarium mycotoxins.

Aging↗

PubMed2003

Bacterial contamination of a cornea tissue bank: implications for the safety of graft engineering.

PURPOSE: To analyze the difficulties involved in managing an episode of bacterial contamination in a cornea bank. We describe (1) the circumstances of bacterial contamination discovery, (2) the methods used to investigate the outbreak, (3) the corrective measures adopted, and (4) the method introduced to improve the reaction capacity in case of bacterial contamination. METHODS: All the samples collected were cultured in an attempt to identify the environmental reservoir of the contaminated epidemic clone. Bacteria were identified by Gram stain, oxidase test, and biochemical characteristics. The clonality of the strains was assessed by pulsed-field gel electrophoresis. RESULTS: The bacterial contamination was confirmed for 28 corneas, and 70 additional corneas were discarded. The source of the contamination was identified 17 days after the beginning of the episode. It consisted of a clonal bacterial strain that was found in trypan blue, the dye, used to examine all the tissues. The contaminating bacterium was Burkholderia cepacia, a well-known nosocomial pathogen. A total of 169 grafted corneas had been checked with the contaminated reagent. No cases of post-graft infection were recorded. CONCLUSION: Trypan blue played a major role in this outbreak. The mode and chronology of contamination remain unresolved. This exceptional event emphasizes the risk of bacterial contamination in tissue/cell banks, the necessity to improve methods for its prevention, and procedures to limit its consequences.

Burkholderia Infections↗

PubMed2001

Environmental and body contamination through aerosols produced by high-speed cutters in lumbar spine surgery.

STUDY DESIGN: A cadaver study to evaluate contamination in the operating room through the use of a high-speed bone cutter. OBJECTIVES: To determine the grade of contamination of animate and inanimate objects through an aerosol intraoperatively, produced by a high-speed cutter during lumbar laminectomy. SUMMARY OF BACKGROUND: In spinal surgery, high-speed cutters are used that produce an aerosol consisting of a mixture of irrigation solution, blood, and tissue debris. Such aerosols can be contaminated with potential pathogens. The surgical personnel and the environment are therefore exposed to a contamination risk. METHODS: Laminectomies at three points (L2-L4) were performed on a human cadaver using a high-speed cutting device. The aerosol produced by the irrigation solution was contaminated with Staphylococcus aureus ATCC 12600. To detect the contamination of the environment and of the surgical team, surveillance cultures were used. RESULTS: By air sampling, staphylococci were detected in the operating room at an extension of 5 by 7 m. The surgical team showed extensive face and body contamination with S. aureus. Despite protection by a barrier drape, similar contamination was observed on both the cadaver's head and the anesthesiologist. CONCLUSIONS: The use of high-speed cutters in spinal surgery produces an aerosol that can be contaminated with blood-borne pathogens from infected patients. This aerosol is spread over the whole surgical room and contaminates the room and all personnel present. It is therefore critical to ensure that effective infection control measures are performed, not only by the surgeons but by everyone present in the operating room. The room itself must be sufficiently disinfected after such procedures.

Aerosols↗

PubMed2006

Forensic application of microbiological culture analysis to identify mail intentionally contaminated with Bacillus anthracis spores.

The discovery of a letter intentionally filled with dried Bacillus anthracis spores in the office of a United States senator prompted the collection and quarantine of all mail in congressional buildings. This mail was subsequently searched for additional intentionally contaminated letters. A microbiological sampling strategy was used to locate heavy contamination within the 642 separate plastic bags containing the mail. Swab sampling identified 20 bags for manual and visual examination. Air sampling within the 20 bags indicated that one bag was orders of magnitude more contaminated than all the others. This bag contained a letter addressed to Senator Patrick Leahy that had been loaded with dried B. anthracis spores. Microbiological sampling of compartmentalized batches of mail proved to be efficient and relatively safe. Efficiency was increased by inoculating culture media in the hot zone rather than transferring swab samples to a laboratory for inoculation. All mail sampling was complete within 4 days with minimal contamination of the sampling environment or personnel. However, physically handling the intentionally contaminated letter proved to be exceptionally hazardous, as did sorting of cross-contaminated mail, which resulted in generation of hazardous aerosol and extensive contamination of protective clothing. Nearly 8 x 10(6) CFU was removed from the most highly cross-contaminated piece of mail found. Tracking data indicated that this and other heavily contaminated envelopes had been processed through the same mail sorting equipment as, and within 1 s of, two intentionally contaminated letters.

Air Microbiology↗

PubMed2006

Staphylococcus aureus contamination on the surface of working tables in ward staff centers and its preventive methods.

We investigated Staphylococcus aureus (S. aureus) contamination on the surface of working tables in ward staff centers and the effects of disinfection by wiping with 80% (v/v) ethyl alcohol on this contamination. When working tables were not regularly disinfected or washed, S. aureus [methicillin-sensitive S. aureus (MSSA) and/or methicillin-resistant S. aureus (MRSA)] was detected in 29 (51.8%) of 56 tables in 6 wards investigated. MRSA was detected in 17 (30.4%) of 56 tables and in all investigated wards. The S. aureus contamination density on the entire surface of the S. aureus-contaminated tables was 2081+/-8915 (mean+/-S.D.) colony-forming units (cfu) (n=29, range, 10-4.8x10(4) cfu), and the MRSA contamination density on the entire surface of the MRSA-contaminated tables was 158+/-200 cfu (n=17, range, 10-7.4x10(2) cfu). The second investigation was performed immediately after working tables not regularly disinfected or washed were disinfected by wiping once with 80% (v/v) ethyl alcohol, and MRSA was detected in 5 (8.9%) of 56 tables. The contamination density on the entire surface of the MRSA-contaminated tables was 36+/-30 cfu (n=5, range, 10-80 cfu). The third investigation was performed immediately after working tables not regularly disinfected or washed were disinfected by wiping with 80% (v/v) ethyl alcohol twice with a 1-min interval, and no S. aureus contamination was observed in any of 56 tables. These results suggest that disinfection by wiping once with 80% (v/v) ethyl alcohol could not completely eliminate MRSA in particulates. For the disinfection of the MRSA-contaminated surface of working tables and the removal of particulates, regular disinfection by wiping with 80% (v/v) ethyl alcohol is necessary.

Anti-Bacterial Agents↗

PubMed2006

Contamination: a comparison of 2 personal protective systems.

BACKGROUND: The purpose of this study was to examine the difference in self-contamination rates and levels of contact and droplet protection associated with enhanced respiratory and contact precautions (E-RCP) and a personal protective system that included a full body suit, personal protective equipment and a powered air-purifying respirator (PAPR). METHODS: In this prospective, randomized, controlled crossover study, 50 participants donned and removed E-RCP and PAPR in random order. Surrogate contamination consisted of fluorescein solution and ultraviolet (UV) light- detectable paste, which was applied after each ensemble was donned. A blinded evaluator inspected participants for contamination using a UV lamp after removal of each ensemble. Areas of contamination were counted and measured in square centimetres. Donning and removal violations were recorded. The primary end point was the presence of any contamination on the skin or base clothing layer. RESULTS: Participants wearing E-RCP were more likely to experience skin and base-clothing contamination; their contamination episodes measuring > or = 1 cm2 were more frequent, and they had larger total areas of contamination (all p < 0.0001). The anterior neck, forearms, wrists and hands were the likeliest zones for contamination. Participants donning PAPR committed more donning procedure violations (p = 0.0034). Donning and removing the PAPR system took longer than donning and removing E-RCP garments (p < 0.0001). INTERPRETATION: Participants wearing E-RCP were more likely to experience contamination of their skin and base clothing layer. Those wearing PAPR required significantly more time to don and remove the ensemble and violated donning procedures more frequently.

Cross-Over Studies↗

PubMed2005

Simple enzymatic means to neutralize DNA contamination in nucleic acid amplification.

Reverse transcription PCR (RT-PCR) is prone to false positives when contaminating DNA molecules are present at the start of a reaction. Contaminants that derive from earlier work using a given primer pair (carryover PCR products) are of particular concern when those primers are used routinely, as in clinical diagnostics or environmental monitoring. In addition, contamination by genomic DNA can significantly interfere with quantitative and qualitative analysis of RNAs by RT-PCR. Here we describe contaminant restriction (ConR), a method that can be used to neutralize carryover and genomic DNA contamination in RT-PCR studies. Restriction enzymes (REs) added to the amplification cocktail cleave contaminant DNA molecules while sparing the intended target nucleic acid. Restriction, reverse transcription, and amplification steps all take place in the same sealed vessel, thus avoiding any danger of recontamination. ConR eliminates carryover contamination in PCR without compromising target sequence amplification. Because the method is effective against both genomic and carryover contamination, it can be employed routinely in one-step RT-PCR, whatever the RNA target or the nature of the potential DNA contaminant. A variation of this decontamination method, amplicon primer site restriction (APSR), is effective specifically against carryover contamination. APSR, unlike ConR, can be applied during PCR-based amplification of DNA target molecules.

DNA↗

PubMed2005

Trends in blood culture contamination: a College of American Pathologists Q-Tracks study of 356 institutions.

CONTEXT: Blood culture contamination extends hospital stays and increases the cost of care. OBJECTIVES: To measure blood culture contamination rates in a large number of institutions over time and to elucidate practice patterns and demographic factors associated with sustained reduction in contamination rates. DESIGN: Longitudinal cohort study of 356 clinical laboratories that provided quarterly data about blood culture results, using a uniform definition of contamination. Mixed linear model analysis of the 1999 through 2003 data set. RESULTS: Blood culture contamination was significantly higher in institutions that used nonlaboratory personnel to collect blood (P = .03) and significantly lower in facilities that used a dedicated phlebotomy team (P < .001). Higher volume of blood collection was significantly associated with lower contamination rates (P < .001). Continued participation in the Q-Tracks monitoring program was associated with significant and progressive reduction in contamination rates. By the fifth year of participation, the median institution had reduced its blood culture contamination rate by 0.67% (P < .001). CONCLUSIONS: Institutions that use decentralized patient-centered personnel rather than dedicated phlebotomy teams to collect blood cultures experience significantly higher contamination rates. Long-term monitoring of contamination is associated with sustained improvement in performance.

Adult↗

PubMed2002

[Study of Salmonella contamination of restaurant meat products collected over a period of one year].

The study has been carried out on 898 food samples of animal origin: bovin meat, ovin, porcin, rabbit, turkey and chicken in 1998 from auto-control food service of Chahed laboratory. II consisted in studying and identifying salmonella serovars and to determine the nature of the most contaminated meat products. The results of the study are as follows: 3.7% of meat product samples are contaminated by salmonella. On the 480 samples of bovin meat, 4.2% are contaminated by salmonella. 3.8% ovin meat is contaminated by salmonella, 1.7% turkey meat and 3.6% chicken meat. Rabbit meat are not contaminated by salmonella. As far as the products of a bovin origin are concerned the results are as follows: -2.7% of meat is contaminated by salmonella, 5.3% of mechanically separated meat and 7.7% of giblets are also contaminated. Therefore salmonella contaminates 4.3% of red meat and 2.6% of fowl. S. anatum, Corvallis, typhimurium, Braenderup, Zanzibar, Enteritidis, Livingstone are different detected serovars. S. anatum represents 40% of contamination whereas. S. typhimurium represents 12% Of contaminations.

Data Collection↗