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PubMedDate not supplied

[Prevalence of Mycoplasma orale as a contaminant of cell cultures in Argentina].

Over a period of 4 years 200 cell cultures were analysed for the presence of mycoplasma. Cultures were established cell lines from different origins, namely monkey, mouse and human, hybrid cell cultures and primary cultures. The cultures belonged to various research and industrial laboratories located in different areas of the country. Seventy per cent of investigated cultures were found to be contaminated with mycoplasma using a DNA fluorescent stain. Fifty cultures, selected at random out of the contaminated cultures, were further investigated to identify the prevalent serotype. For that purpose immunofluorescent reactions were performed using immune sera raised against several mycoplasma strains routinely found among contaminated cultures. Forty one cultures were contaminated with a single type of mycoplasma, whereas in the remaining nine, two or even three serotypes were detected. Mycoplasma orale II contaminated 40% of single infected cultures, followed by M. hyorhinis and A. laidlawii-A (12% each), M. arginini (5%), M. orale III (8%), A. laidlawii-B (2%). We were unable to serotype the remaining positive cultures, because of the lack of a full battery of immune sera against all known serotypes. The prevalence of M. orale in mycoplasma contaminated cultures thus far tested, indicates that human handling would be the main source of infection. This situation could be modified by avoiding mouth pipetting and adopting good microbiological techniques.

Acholeplasma↗

PubMed1991

Bacteriologic studies of food and water consumed by children in Myanmar: 2 Lack of association between diarrhoea and contamination of food and water.

The association between contamination of morning samples of food and water of 208 children aged 6-29 months and the incidence of diarrhoea was investigated for 3 months in Yangon, Myanmar. Contamination of the samples was determined by isolation of faecal coliforms (FC) by standard methods. The children were divided into three groups, high, medium and low, according to the proportion of food and water samples found to be contaminated. The incidence of diarrhoea was recorded by weekly recall. Of the 779 food samples, 504 (65%), and of the 860 drinking water samples, 187 (22%) were positive for FC. The association between food and water contamination and the incidence of diarrhoea was assessed by comparing the cumulative incidences in the high and medium groups with that in the low group which served as reference. Diarrhoea risk ratios (RR) for children in the medium and high contamination groups (food, RR = 1.04 in medium and 0.78 in high vs 1 in low; water, RR = 0.73 and 0.73 vs 1) were not significantly different from those who were in the low-contamination group even after controlling for the confounding variables.

Child, Preschool↗

PubMed1991

Fluid contamination during orthopaedic procedures. A study of incidence, location, and prevention.

Certain orthopaedic procedures may expose health care providers to contamination of scrub clothing, personal undergarments, and/or skin by patients' body fluids. The incidence and site of fluid contamination were studied for an orthopaedic surgeon and his assistant during 54 orthopaedic operations from March through May 1989. Contamination was recorded in 35 of the cases (65%) for the surgeon, and in 37 (69%) for the assistant. The sites of contamination spanned the length of the lower extremities, with an overall 34% incidence above the knee. The surgeon and assistant then monitored fluid contamination during 43 cases from March through May 1990 while wearing water-impervious surgical pants. An additional 16 clinicians also tested these pants and answered questions regarding their comfort and utility. No cases of fluid contamination were recorded during the second phase of the study. The garment was reported to be comfortable and did not appear to add a heat factor, even with the use of lead aprons during fluoroscopic procedures.

Academic Medical Centers↗

PubMed1990

Transabdominal placental biopsy in the second and third trimesters of pregnancy: what is the risk of maternal contamination in DNA diagnosis?

We investigated the risk of maternal contamination in antenatal DNA diagnosis after second- and third-trimester transabdominal placental biopsy. For this purpose, we compared the restriction fragment length polymorphism (RFLP) patterns of 11 chorionic villus DNA samples after late chorionic villus sampling (CVS) with those of the corresponding maternal DNA. Ten of 11 aspirated tissue samples were not separated from maternal contamination before DNA extraction. All 11 mother-embryo pairs were informative for analysis of maternal contamination, ie, the mother showed one RFLP allele not present in the embryo. In none of the 11 cases did the fetal DNA show maternal contamination after molecular hybridization, although ten samples were contaminated with maternal tissue macroscopically and microscopically. Despite some maternal tissue admixture, the risk of contamination seems to be lower in the second- and third-trimester CVS than in first-trimester CVS, based on previous reports and our own experiences. This is most likely due to the anatomically closer contact of villi and decidua in the first trimester of pregnancy.

Alleles↗

PubMedDate not supplied

[3 possible sources of microbiologic contamination in the preparation of formulations for parenteral nutrition].

It is well known that the microbiological control of "all in one" nutritional preparations is difficult. In this work we evaluated and compared the potential contaminants that may be present in the process of manufacturing in a Centralized Unit of Parenteral Nutrition. The study has been centered on the microbiological contamination that may be introduced by the technician, by the raw materials, and that existing in the work area. A microbiological contact technique was used. The results obtained showed that the main microbiological contaminants are introduced by the technician when not observing strict aseptic measures. Another source of contamination is represented by PVC bags when they are manipulated in the pre-sterile area and are not sprayed with alcohol 70 degrees. Therefore, PVC contamination arises from the hands of the technician. Significant differences in contamination between hands washed with germicidal soap and sterile gloves and between clean and sterile surgical dressing could not be demonstrated.

Food Handling↗

PubMed1987

[Decontamination effectiveness of Ca-, Zn- and MnDTPA chelates in internal contamination with Cs-137, Ce-144, J-131, Sr-90 radioisotopes].

The studies were carried out on 240 rabbits divided into 4 groups, in which, after contamination with i.v. radioisotopes 137Cs (A), 144Ce (B), 131J (C), 90Sr (D), Ca-, Zn-, MnDTPA chelates were used in 12.5% water solutions in doses of 0.4 g/kg of body weight. The evaluation of the decontaminating effectiveness of the above DTPA compounds, taking into account veterinary-clinical and veterinary-sanitary aspects, was made with to the individual radioisotopes on the basis of radiometric studies. These studies carried out after 1,2,4,6,15 days from the contamination, by using a measurement system, concerned the following organs and tissues: blood, brain, heart, muscles of the thigh and arm, lungs, kidneys, liver, stomach, colon, bone, thyroid gland. The results expressing the per cent values of radioactivity of the organs in relation to the dose of the radioisotopes introduced into the organism and to the value of radioactivity of the particular organs in Bq/100 mg of ash, including discussion and conclusions, are presented in individual groups. From these data it can be assumed for practical veterinary purpose that Ca-, Zn-, MnDTPA chelates show an effective action with respect to the veterinary-clinical aspect in contamination with radiocerium, and with respect to the veterinary-sanitary aspect in contamination with radiocerium and radioiiodine; less effective action with respect to the veterinary-sanitary aspect, and ineffective with respect to the veterinary-clinical aspect in contamination with radiocesium; negative one with respect to both aspects in contamination with radiostrontium. As regards the individual chelating compounds, the most effective can be recognized sodium zinc salt of DTPA.

Animals↗

PubMed1985

[Evaluation of the risk of internal contamination of persons working in isotope laboratories].

The investigation covered 484 workers. Altogether 1787 determinations have been made, in this--1648 internal contaminations and 139 contaminations of air, hand skin and working surfaces. The internal contaminations (22% of results) resulted mainly from deviation from radiological protection rules and were reduced through certain changes. Those were tritium contaminations (application of tritium radioluminiscence dyes) and 125--and 131-iodine radioisotopes (in nuclear medicine laboratories) the highest levels of which were 20 mSv and 0.25% ALI respectively. The results of 238Pu air contamination measurements have indicates that the dust arising during the production of smoke detectors (with 238PuO2 sources) probably has no respirable fraction properties, which confines its absorption in lower segments of the respiratory tract. It has been demonstrated that in Poland there is no need of constructing a permanent central system of internal contamination control.

Air Pollutants↗

PubMed1985

Efficacy of chlorhexidine cleansing in reducing contamination of bagged urine specimens.

To determine the effectiveness of precleansing with chlorhexidine gluconate-cetrimide in reducing the contamination rate of bagged urine specimens, 62 infants admitted to a children's hospital were randomly assigned to either receive (32 infants) or not receive (30) cleansing before bag application. Perimeatal swabs were taken before bag application and, in the treated group, after cleansing. Of the specimens from the treated group 69% were found to be contaminated, compared with 73% of those from the no-cleansing group. Chlorhexidine was ineffective in eliminating the perimeatal flora in 75% of the infants. The same organisms were present on the perimeatal swab and in the urine specimen in 95% of the infants in the treated group and 96% of those in the no-cleansing group. To estimate the contamination rate of urine specimens routinely cultured in the laboratory, 200 consecutive specimens (142 midstream and 58 bagged) were cultured. The contamination rate of the midstream urine specimens was 15%, compared with 66% for the bagged specimens. The cost of laboratory processing of contaminated bagged urine specimens at the hospital in 1983 may have been as high as $13 365. Chlorhexidine cleansing does not appear to be cost-effective. Further randomized controlled studies are needed to evaluate the effectiveness of other cleansing agents in reducing the contamination rate of bagged urine specimens.

Chlorhexidine↗

PubMed1981

Eliminating mycoplasmas from contaminated cell cultures.

Mycoplasmas are bothersome contaminants in cell cultures. Cells derived from various sources are subject to contamination and although many procedures have been suggested to eliminate the contaminating mycoplasmas, there is no simple, rapid and effective method for eliminating them. We have devised a method for the selective killing of mycoplasmas based on the differences between the nucleic acid metabolism of mycoplasmas and that of tissue culture cells. Whereas the nutritional requirements of mycoplasmas for nucleic acid precursors can be met by purine and pyrimidine bases, mammalian cells do not incorporate the free bases. The approach was to selectively incorporate the free base analogue 5-bromouracil (5-BrUra) into the mycoplasmas followed by photosensitization of the DNA containing 5-BrUra by low concentrations of the fluorochrome 33258-Hoechst. Such treatment renders the mycoplasma DNA very susceptible to breaks induced by visible light. The unusually high A + T content in mycoplasma DNA makes these organisms suitable candidates for the induction of breakage by the combined action of 5-BrUra, 33258-Hoechst and light because 33258-Hoechst has a high affinity for A + T base pairs and an even higher affinity for A-BrUra base pairs. We report that Mycoplasma hyorhinis and Acholeplasma laidlawii contaminating Chinese hamster cells were selectively killed by our technique, and cured clones of cells were easily obtained from the treated cell cultures. The technique proved efficient in curing BHK-21 and RAG cells from unknown contaminating mycoplasmas suggesting that this technique could be generally applied to eliminate contaminating mycoplasma strains from mammalian cell culture.

Animals↗

PubMed1983

Conversation in the operating theater as a cause of airborne bacterial contamination.

Using microspheres of human albumin sprayed on the face and in the nostrils under the facemask, we studied the role of conversation in contaminating the operating-room environment in addition to the microbial contamination of the air in an empty and in an occupied operating room. Conversation consistently increased the number of microspheres found in the simulated wound. The spatial relationship between the mask and the hood was important in reducing contamination. A complete hood overlapping the mask, with no gaps at the sides or bottom of the mask, was most efficient. The air contamination was increased by the presence of operating-room personnel and varied in different parts of the theater according to the density of traffic. We concluded that conversation contributes to airborne contamination in the operating theater but that contamination from this source can be lessened by wearing a face-mask that extends underneath an overlapping hood.

Air Microbiology↗

PubMed1982

The effects of vaginal contamination on two pulmonary phospholipid assays.

During the examination to confirm premature rupture of membranes, amniotic fluid unavoidably contaminated with cervical mucus and other vaginal debris can often be obtained from the posterior fornix. This study was undertaken to determine the validity of phospholipid measurements on contaminated amniotic fluid. Fifteen paired amniocentesis and vaginally contaminated samples of amniotic fluid were used to measure the lecithin/sphingomyelin ratio and saturated phosphatidylcholine (SPC). The amniocentesis specimens had a mean L/S ratio of 3.94 +/- 0.22 (mean +/- SEM), and contaminated samples had a mean L/S ratio of 3.82 +/- 0.29 (mean +/- SEM). Paired t-test was unable to demonstrate a significant difference (p greater than 0.10), and the correlation coefficient between paired L/S samples was r = 0.79. SPC measurements on the amniocentesis fluid had a mean value of 1,243 microgram/DL +/- 217 (mean +/- SEM) as compared to the contaminated-specimen mean of 1.375 micrograms/dl 223 (mean +/- SEM). Paired t-test likewise was unable to demonstrate a significant difference (p greater than 0.10), and the correlation coefficient between paired SPC samples was r = 0.93. Within the design of this study, we were unable to demonstrate a statistically significant effect of brief vaginal contamination on the measurement of the L/S ratio or SPC.

Amniocentesis↗

PubMed1994

Bacteriological evaluation of a new air turbine handpiece for preventing cross-contamination in dental procedures.

An autoclavable air turbine handpiece, Air Flushing Clean System (AFCS) (Osada Electric Co., Ltd., Tokyo, Japan) was developed for use in dentistry with the objective of reducing cross-contamination. Its potential for bacterial contamination was investigated in vitro using two bacterial strains (Streptococcus mutants ATCC 25175 and Staphylococcus aureus FDA 209 P). In theory, this device should prevent cross-contamination of the internal water and air lines of the handpiece, by maintaining an internal positive pressure even after the turbine is stopped. In the present study, this AFCS device was found to reduce the bacterial contamination within the air turbine handpiece more effectively than the conventional handpiece used according to accepted protocol. The reduction of such contamination by the AFCS is in keeping with the recent objective of the American Dental Association to reduce cross-contamination during dental procedures.

Bacteriological Techniques↗

PubMed1994

Restriction fragment length polymorphism analysis of isotype-labeled polymerase chain reaction-amplified human papillomavirus DNA combines sensitivity with built-in contaminant detection.

The detection of low copy number DNA in archival tissue has been revolutionized by polymerase chain reaction (PCR), but widespread acceptance of this technique for diagnostic purposes has been hampered by problems with contamination. There is a technique, restriction fragment length polymorphism analysis for characterizing PCR-amplified human Papillomavirus (HPV) nucleic acids, that reportedly provides for increased sensitivity in detection of both target and contaminating sequences. This technique is a modification of standard restriction fragment length polymorphism and involves radiolabeled nucleotide incorporation during PCR and restriction enzyme digestion of the products followed by high resolution polyacrylamide gel electrophoresis. The amount of initial target DNA amplified by PCR that can be detected by isotope labeling or ethidium staining was compared, as was the sensitivity of the two methods for analyzing a PCR product of fixed amount. The sensitivity of ethidium staining or autoradiography was comparable for detection of initial target HPV DNA by PCR. However, for subsequent typing of amplified HPV DNA by restriction fragment length polymorphism, isotope-labeled products provided an approximately 125-fold increase in sensitivity over ethidium staining, with a maximum of 625-fold greater sensitivity with a 3-day exposure. The detection of low levels of potential contaminants in PCR-amplified HPV DNA was determined in a serial analysis of cervical biopsies. Contaminating DNA was identified in two gels where multiple samples yielded the same restriction pattern. On re-isolation of genomic DNA, these products of contaminating DNA were not seen. Extrapolating from the above experiments, the contamination of many samples would have escaped detection by ethidium staining alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗

PubMed1994

Reduction in operatory mercury levels after contamination or amalgam removal.

The threshold limit value (TLV) for occupational exposure to mercury can be exceeded in the dental operatory after a contamination event or during certain dental procedures. The objective of this study was to determine the time required for the mercury vapor levels to return to baseline in both non-ventilated and ventilated operatories after they had been contaminated with mercury to the TLV of 0.050 mg/m3; and to evaluate the efficiency of an activated charcoal filtering device for removing mercury vapor. The results showed that even in a poorly ventilated operatory, the mercury vapor level returned to background within 20-30 minutes after a contamination, and within 10-20 minutes when the operatory was ventilated. The filtering device reduced the level of mercury vapor by approximately 25% during a continuous contamination event, but did not clear the operatory faster than normal settling after a limited source contamination. The filter caused a significant reduction in mercury in the breathing zones of the patient and dentist during and after amalgam removal, but did not eliminate the exposure. This study demonstrated the difficulty in contaminating an operatory with mercury vapor and confirmed the limited time mercury remains airborne, presumably due to its density and affinity for surfaces.

Air Pollution, Indoor↗

PubMed1993

Effect of iodophor vs iodine tincture skin preparation on blood culture contamination rate.

OBJECTIVE: To determine if iodine tincture is a more effective skin antiseptic for blood culture collection than povidone-iodine, an iodophor. DESIGN: Pairwise comparisons across phases. In phases 1 and 3, blood culture skin preparation was performed with the iodophor; in phases 2 and 4, skin preparation was performed with iodine tincture. SETTING: Emergency department of a large urban teaching hospital. PATIENTS: All adult patients seen in the emergency department who had blood cultures collected because a systemic bacterial infection was suspected. MAIN OUTCOME MEASURE: The blood culture contamination rate for the iodophor and iodine tincture skin preparations. RESULTS: A total of 8467 blood cultures were collected during the study, and 421 (4.97%) were classified as contaminated. The contamination rate for the blood cultures collected using the iodophor was 6.25%, and the contamination rate for the cultures using iodine tincture was 3.74%; this difference is statistically significant (P < .00001). CONCLUSIONS: The effectiveness of the skin antiseptic may be an important factor in determining contamination rate in blood culturing. If these results are confirmed by others, then institutions that have a high blood culture contamination rate when using an iodophor for skin preparation should consider changing to iodine tincture.

Anti-Infective Agents, Local↗

PubMed1993

Contamination of human ovarian follicular fluid and serum by chlorinated organic compounds in three Canadian cities.

OBJECTIVES: To determine the extent of contamination of ovarian follicular fluid and serum samples in women undergoing in-vitro fertilization and to study the effect of the contaminants on reproductive outcome. DESIGN: Inception cohort study. PATIENTS: Seventy-four women undergoing in-vitro fertilization at three regional clinics in Halifax, Hamilton, Ont., and Vancouver. MAIN OUTCOME MEASURES: Follicular fluid and serum levels of contaminants, cleavage rates and time to cleavage of first egg. RESULTS: Five chlorinated organic chemicals were frequently found in the two types of samples: alpha-chlordane (ALCH), dichlorochlorophenylethylene (DDE), heptachloroepoxide-oxychlordane (OXCH), hexachlorobenzene (HCB) and polychlorinated biphenyl (PCB). The levels were generally low. Regional differences between the three clinics were present. Samples from the Halifax clinic had the lowest frequency and level of contamination. The source of drinking water (well, bottled or municipal) was an important confounder. The concentrations of the five contaminants did not affect the cleavage rate or the time to cleavage of the first egg. CONCLUSION: Trace amounts of toxic and persistent chlorinated organic chemicals found in the follicular fluid of Canadian women undergoing in-vitro fertilization did not seem to have any adverse biologic effect on the rate of fertilization and the time to cleavage. Reasons for regional differences in the concentrations of contaminants require further study.

British Columbia↗

PubMed1996

[Effect of premortal stress on the endogenous microbial contamination of broiler carcasses].

A study was undertaken to determine the interrelation between premortal stress and endogenic contamination. In 370 broilers the influence of transport, of a 48-h rest period and of an additional heat stress on the bacterial translocation was investigated. Even the normal transportation caused a contamination rate of nearly 50 per cent. 10 per cent of the transported animals suffered from a bacteriaemia induced by stress. The control group showed a significantly lower contamination rate. The rest time reduced the frequency of contamination. Heat stress did not have an influence on the contamination rate. The conclusion is that stress is aggravating the microbial risk for the consumer of poultry meat. Further research is necessary for characterizing the process of endogenic contamination.

Abattoirs↗

PubMed1996

[The effect of the Mycoplasma contamination of 2 kidney cell sublines from the kangaroo rat on their karyotypic structure].

The karyotypic variability has been investigated for two cell sublines of Rat kangaroo kidney cultured for 40-160 days after contamination with Acholeplasma laidlawii, strain PG-8. The contaminated cultures did not differ from non-contaminated ones in cell distribution for chromosome number. The majority of cells of subline NBL-3-11 with modal number of chromosomes displayed the main structural variant of the karyotype (SVK)--2+2+2+2+2+1; in subline NBL-3-17 the main SVK being 3+3+3+3+3+2. A comparison of intact cultures of these sublines in cell distribution for chromosome number show just the opposite direction of aneuploidy processes: cell heterogeneity for chromosome number decreased in NBL-3-11 and increased in NBL-3-17. The quantity of chromosomal aberrations, primarily chromosomal breaks, increases within 40-160 days of cultivation of contaminated cells of subline NBL-3-11. The number of chromosomal aberrations, mainly at the expense of dicentrics due to telomeric associations, increases after 40 days of cultivation of subline NBL-3-17 contaminated cells. During a long-term cultivation (110 days) of subline NBL-3-17 intact cells, there is an increase in the number of chromosomal aberrations, mainly dicentrics, whereas the extent of chromosomal breaks appears much less. The present results and other additional experimental data make it possible to suppose that the increase in chromosomal instability seen in subline NBL-3-17 at a long-term cultivation may be characteristic of this culture, in distinction to subline NBL-3-11. The most frequent breaks were seen in chromosomes 1, 2 and X of intact and contaminated cells in both the sublines. Chromosomes 1, 2 and 4 are mainly involved in dicentric formations by q (long) arms. The role of dicentrics in cell adaptation to in vitro conditions is discussed.

Acholeplasma laidlawii↗