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PubMed2003

Importance of Gram-positive naphthalene-degrading bacteria in oil-contaminated tropical marine sediments.

AIMS: The aim of this study was to isolate, characterize and evaluate the importance of naphthalene-degrading bacterial strains from oil-contaminated tropical marine sediments. METHODS AND RESULTS: Three Gram-positive naphthalene-degrading bacteria were isolated from oil-contaminated tropical intertidal marine sediments by direct isolation or enrichment using naphthalene as the sole source of carbon and energy. Bacillus naphthovorans strain MN-003 can also grow on benzene, toluene, xylene and diesel fuel while Micrococcus sp. str. MN-006 can also grow on benzene. Staphylococcus sp. str. MN-005 can only degrade naphthalene and was not able to use the other aromatic hydrocarbons tested. Strain MN-003 possessed the highest maximal specific growth rate with naphthalene as sole carbon source. An enrichment culture fed with naphthalene as sole carbon source exhibited a significant increase in the relative abundances of the three isolates after 21 days of incubation. The three isolates constituted greater than 69% of the culturable naphthalene-degrading microbial community. Strain MN-003 outcompeted and dominated the other two isolates in competition studies involving batch cultures inoculated with equal cell densities of the three isolates and incubated with between 1 and 10 mg l-1 of naphthalene. CONCLUSIONS: Three Gram-positive naphthalene-degrading bacteria were successfully isolated from oil-contaminated tropical marine sediments. Gram-positive bacteria might play an important role in naphthalene degradation in the highly variable environment of oil-contaminated tropical intertidal marine sediments. Among the three isolates, strain MN-003 has the highest maximal specific growth rate when grown on naphthalene, and outgrew the other two isolates in competition experiments. SIGNIFICANCE AND IMPACT OF THE STUDY: This research will aid in the development of bioremediation schemes for oil-contaminated marine environments. Strain MN-003 could potentially be exploited in such schemes.

Bacillus↗

PubMedDate not supplied

Effective management of microbial contamination in cultured skin substitutes after grafting to athymic mice.

Cultured skin substitutes have become therapeutic alternatives for treatment of acute and chronic skin wounds, but all models of these substitutes are avascular and susceptible to microbial destruction during vascularization. To develop a practical management protocol for increased survival of skin substitutes, experimental wounds were contaminated with Pseudomonas aeruginosa and treated with a formulation of noncytotoxic antimicrobial agents (polymyxin B, neomycin, ciprofloxacin, mupirocin, amphotericin B) in a nutrient medium (vehicle). Cultured skin substitutes consisting of human keratinocytes and fibroblasts attached to collagen-glycosaminoglycan sponges were grafted to 2 x 2 cm full-thickness wounds on athymic mice that were contaminated with the strain SBI-N of P. aeruginosa at 1 x 10(4), 1 x 10(5), and 1 x 10(6) organisms/wound. Experimental wounds were irrigated with 1 ml/day topical antimicrobial solution for 10 days, and controls received vehicle only. Two, three, and four weeks after grafting, wounds were traced and swabbed for microbial culture and areas were measured with planimetry. At 4 weeks, biopsy samples were scored histochemically for immunoreactivity to HLA antigens. Data analysis by chi-square, analysis of variance, and Tukey's test shows that treatment of contaminated wounds with noncytotoxic topical antimicrobials is associated with an increased area of healed wounds, positive detection of HLA antigens, and negative cultures for P. aeruginosa. These results show that microbial contamination of cultured skin substitutes on full-thickness wounds may be managed effectively during graft vascularization. However, this formulation of antimicrobial agents is not currently approved for human use and is investigational only. Effective management of microbial contamination suggests that clinical efficacy of avascular tissue analogs may be increased by local application of noncytotoxic antimicrobial agents.

Journal Article↗

PubMed2000

Antibiotic-labeled probes and microvolume fluorimetry for the rapid detection of bacterial contamination in platelet components: a preliminary report.

BACKGROUND: Approximately 1 platelet in 2000 components is bacterially contaminated. Most commonly, contaminating organisms are gram positive skin saprophytes (such as Staphylococcus sp. or Bacillus sp.). A novel approach to the rapid diagnosis of gram positive contamination by the use of a fluorescence-labeled antibiotic probe with affinity for the gram positive cell was investigated. STUDY DESIGN AND METHODS: Two isolates of Staphylococcus epidermidis were inoculated into bags of Day 0 platelets. Quantitative cultures along with a semi-automated screening assay on a microvolume fluorimeter employing a fluorescence-conjugated vancomycin probe was performed for each day of storage. In addition, serial dilutions of the bacteria were added to sterile platelets to achieve a range spanning 10(1) to 10(8) CFUs per mL. RESULTS: All samples with a bacterial contamination of > or =10(5) CFU per mL were detected. Sterile samples were nonreactive. The entire procedure requires three pipetting steps and took less than 1 hour to perform. CONCLUSION: These preliminary results with the use of fluorescence-labeled antibiotics as probes combined with microvolume fluorimetry for the rapid detection of bacterial contamination of platelet components suggest that this is a promising approach. Further studies with additional organisms and alternative conjugates, bacteria, and antibiotics are underway.

Anti-Bacterial Agents↗

PubMed2003

Bacterial contamination of ex vivo processed PBPC products under clean room conditions.

BACKGROUND: Patients undergoing high-dose radio- and/or chemotherapy and autologous or allogeneic PBPC transplantation are at high risk for infections owing to profound immunosuppression. In this study, the rate of microbial contamination of ex vivo processed PBPC products was analyzed, comparing preparation under clean room conditions to standard laboratory conditions. STUDY DESIGN AND METHODS: After implementation of good manufacturing practice conditions in the two participating institutions, the microbial contamination rate of 366 PBPC harvests from 198 patients was determined under certified clean room conditions (Group A) from 2000 until 2002. To investigate influence of improved environmental conditions along with other parameters, this set of samples was compared with a historical control set of 1413 PBPC products, which have been processed ex vivo under a clean bench in a regular laboratory room and were harvested from 626 patients (Group B) from 1989 until 2000. RESULTS: In Group B microbial contamination was found in 74 PBPC products (5.2%) from 57 patients. In Group A microbial growth was detected in 3 leukapheresis products (0.8%) from 3 patients. After exclusion of PBPC products, which were probably contaminated before manipulation, statistical analysis showed a significant difference (chi2= 10.339; p < 0.001). CONCLUSION: These data suggest an impact of clean room conditions on the bacterial contamination rate of PBPC products. To identify confounding variables, variables like technique of leukapheresis, culture methodology, and microbial colonization of central venous catheters were taken into account. Further variables might be identified in following studies.

Bacteria↗

PubMed1991

The effect of endotoxin-contaminated medium on in vitro fertilization and development of bovine oocytes matured in vitro.

The purpose of this study was to determine whether the presence of bacterial endotoxin in the bovine serum albumin (BSA) used to supplement media utilized for sperm preparation and co-culture of bovine sperm and oocytes affects in vitro penetration and embryonic development of oocytes matured in vitro. The chromogenic limulus amoebocyte lysate (LAL) test was used for quantification of the content of endotoxin. The proportion of penetrated ova was significantly greater (P greater than 0.0005) for the endotoxin-contaminated group (89%) versus the non-contaminated group (61%), but this was probably not due to endotoxin contamination. The presence of endotoxin resulted in a high rate of polyspermy (27% versus 4%, respectively; P greater than 0.0005), while the occurrence of parthenogenetic activation was the same for each group (8%). The proportion of total embryos put into culture that developed to the blastocyst stage by day 8 was similar (30% and 26%) for the contaminated and non-contaminated group, respectively. Fifty-three and 69%, respectively, hatched on day 10. These results suggest that endotoxin induces polyspermy, but has no adverse effect on embryonic development.

Animals↗

PubMed2001

Surgical area contamination--comparable bacterial counts using disposable head and mask and helmet aspirator system, but dramatic increase upon omission of head-gear: an experimental study in horizontal laminar air-flow.

The effect of different head coverings on air-borne transmission of bacteria and particles in the surgical area was studied during 30 strictly standardized sham operations performed in a horizontal laminar air flow (LAF) unit. The operating team members wore disposable gowns plus either a non-sterile head covering consisting of a squire type disposable hood and triple laminar face mask, a sterilized helmet aspirator system or no head cover at all. In the wound area both types of head cover resulted in low and comparable air (means of 8 and 4cfu/m(3)) and surface contamination (means of 69 and 126cfu/m(2)/h) rates. Omission of head-gear resulted in a three- to five-fold increase (P > or = 0.01- 0.001), depending on site sampled air contamination rate (mean of 22cfu/m(3)) whereas the bacterial sedimentation rate in the wound area increased about 60-fold ( P > or = 0.0001). A proper head cover minimized the emission of apparently heavy particles that were not removed by the horizontal LAF and contained mainly streptococci, presumably of respiratory tract origin. Dust particle counts revealed no differences between the three experimental situations. No correlation between air and surface contamination rates or between air contamination and air particle counts was found. We conclude that, from a bacteriological point of view, disposable hoods of squire type and face masks are equally as efficient as a helmet aspirator system and both will efficiently contain the substantial emission of bacteria-carrying droplets from the respiratory tract occurring when head cover is omitted. Finally, the use of bacterial air counts to assess surgical site surface contamination in horizontal LAF units must be seriously questioned.

Air Microbiology↗

PubMed2002

The effect of 10% povidone--iodine solution on contaminated bone allografts.

The aim of this study was to determine the efficacy of 10% povidone--iodine solution for the decontamination of bone allografts. Bone samples were prepared and tested for sterility using a femoral head removed at the time of primary hip replacement. They were contaminated by a suspension of Staphylococcus epidermidis and ground to measure the quantity of micro-organism attached to the bone. Two levels of contamination were used (1 x 10(3) vs. 1 x 10(4)CFU/mL) to check the efficiency of our method of measurement. Samples of the two groups were decontaminated with 10% povidone--iodine solution using different exposure times. Before decontamination, the count of bacteria attached to the bone was proportional to the bacterial concentration of the contaminating solution. The microbiocidal activity of 10% povidone--iodine solution was the same in both groups. The decontamination time was proportional to the bacterial concentration of the contaminating solution. The results of this preliminary study suggest that a 10% povidone--iodine solution can decontaminate inoculated bone grafts, but a sufficient time of exposure according to the level of contamination must be allowed.

Anti-Bacterial Agents↗

PubMed2002

Contamination of room door handles by methicillin-sensitive/methicillin-resistant Staphylococcus aureus.

We investigated the contamination of room door handles by Staphylococcus aureus in wards of a university hospital. Door handles in 53 (27.0%) of 196 rooms were contaminated by methicillin-sensitive Staphylococcus aureus (MSSA) and/or methicillin-resistant Staphylococcus aureus (MRSA); MSSA was detected on door handles of 41 rooms (20.9%), MRSA on door handles of 17 rooms (8.7%), and MSSA and MRSA on the same door handles of five rooms (2.6%). The density of MSSA contamination was 1-2.6x10(4) colony forming units (cfu)/door handle, and that of MRSA was 1-6.0x10(3) cfu/door handle. The MRSA contamination rate on door handles of rooms with patients with MRSA was 19.0% (4/21 rooms) while that on door handles of rooms with patients without MRSA was 7.4% (13/175); the difference was not significant. These results suggest extensive contamination of MSSA and MRSA in the hospital environment.

Environmental Microbiology↗

PubMedDate not supplied

Epidemiologic evaluation of postoperative wound infection in clean-contaminated wounds: A retrospective study of 239 dogs and cats.

OBJECTIVE: To evaluate risk factors for development of postoperative wound infections in clean-contaminated wounds. STUDY DESIGN: Retrospective clinical study. SAMPLE POPULATION: Two hundred thirty-nine dogs and cats that had clean-contaminated surgical procedures. METHODS: Records of animals that had a clean-contaminated surgical procedure and were prospectively monitored for development of postoperative wound infection were reviewed. Prospective data included signalment, nutritional status, body weight, duration of surgery, surgical procedures, wound classification, surgical site clip time before surgery, hypotension during surgery, the presence of an active distant infection, endocrinopathy, administration of an immunosuppressive agent, administration of antibiotics, and the type of antibiotic used. Additional retrieved data included total anesthesia time, temperature variables, blood loss, and suture material used. RESULTS: Intact males (P =.008) and animals with concurrent endocrinopathy (P =.008) were at a higher risk of development of postoperative wound infection. Total surgery time (P =.02) and total anesthesia time (P =.04) were longer in animals that developed postoperative wound infection. No other factors were statistically significant. CONCLUSIONS: Intact males and animals with a concurrent endocrinopathy were at higher risk of postoperative wound infection after clean-contaminated surgical procedures. CLINICAL RELEVANCE: Time under anesthesia and duration of surgery should be minimized to reduce the risk of wound infection in clean-contaminated surgical procedures.

Anesthesia↗

PubMed2001

High tumour contamination of leukaphereses in patients with small cell carcinoma of the lung: a comparison of immunocytochemistry and RT-PCR.

In small-cell lung carcinoma (SCLC) tumour cell contamination of leukaphereses is unknown. The present study was performed to define appropriate markers for reverse transcriptase polymerase chain reaction (RT-PCR), then to assess the contamination rate of leukaphereses and corresponding bone marrow samples. Immunocytochemistry (ICC) and RT-PCR methods were also compared. Among the 33 patients included, analyses were performed in 16 who had multiple leukaphereses and 17 who had only bone marrow. Leukapheresis products and bone marrow were analysed by ICC using several specific monoclonal antibodies against neural-cell adhesion molecule (N-CAM), epithelial glycoprotein (EGP-40) and cytokeratins (CK). Samples were also analyzed by RT-PCR for expression for N-CAM, synaptophysin, neuron-specific enolase, chromogranin, cytokeratin-18/-19, CEA, EGP-40, apomucin type 1 (MUC-1) and human endothelial cell-specific molecule (ESM-1). Using ICC staining, contaminating tumour cells were detected in 34% of leukaphereses (27% in patients with limited disease and 43% in those with extensive disease). N-CAM was the most reliable marker for detection of contamination. For RT-PCR, CK-19 and CEA were the only appropriate markers. Positive signal rate in leukaphereses increased to 78% (89% for patients with limited disease and 67% for extensive disease). In bone marrow, both techniques were in agreement whereas in leukaphereses, RT-PCR was better than ICC. A high rate of tumour cell contamination was demonstrated not only in bone marrow but also in leukaphereses from SCLC patients. The most appropriate technique was RT-PCR mainly in patients with limited disease.

Adult↗

PubMed2000

[Decontamination of highly polychlorinated biphenyl contaminated indoor areas by complete removal of primary and secondary sources].

A new sanitization concept in a school highly contaminated with polychlorinated biphenyls (PCBs) is described. The maximum indoor air concentration was 13,100 ng/m3 PCB. Initially the average indoor PCB concentrations attained 6,000-7,000 ng/m3. A reduction to 226 +/- 89.1 ng/m3 (n = 24) was achieved. Ten months later the PCB concentration was 171 +/- 57.6 ng/m3 (n = 3). Primary sources were PCB-contaminated elastic sealants and the paint of radiators or heating elements. Also PCB-contaminated materials were walls, floors and ceilings. These secondary contaminations were also relevant for PCB indoor air concentrations. The primary sources were removed dust-free by manual procedures. Contrary to other sanitization concepts all secondary-contaminated PCB materials were also removed with a high-pressure water method specially developed for such cases. Because of the removal of all relevant primary and secondary PCB deposits, a lasting effect can be expected. By this sanitization concept, the use of new and less intensively explored products suppressing the diffusion of PCBs into the indoor air and whose toxicity is hardly known, may be prevented, thus avoiding the need for prolonged control measurements. Before using the above-mentioned new sanitization concept, another concept had been rejected for lack of efficiency, thus avoiding unnecessary costs. The companies performing sanitization should be compelled to accept a defined lowest PCB concentration.

Adult↗

PubMed2006

[Older soil contaminations and human biomonitoring--two typical examples].

AIM: A health risk assessment of inhabitants had to be accomplished in two areas of former color production works, which had caused considerable soil contaminations predominantly with arsenic and lead. METHODS: Samples of soil, blood and urine were analysed during orientation and detail investigations according to the German soil protection laws. RESULTS: The soil investigations revealed high contaminations in some parts of the two areas (maximum concentrations 550 mg arsenic/kg and 9100 mg lead/kg in residential topsoil from depths of 0-35 cm). Contrary to these findings, arsenic levels in the urine and lead levels in the blood of most of the residents were lower than the reference values for the common German population (arsenic 15 microg/L, lead 50-90 microg/L). In some cases of elevated biological concentrations, other sources of exposure could be detected like drinking tea from a tea-pot with a lead-containing glaze or drinking water from a highly contaminated garden well; interventional measures resulted in major decreases in the internal loads of these people. CONCLUSIONS: The investigations clearly showed that an exposure via the pathway soil--water--human can be of serious health concern whereas older soil contaminations are seemingly of low relevance with regard to the direct contact of persons during daily life on those areas. Therefore, it is recommended to increase the soil examination values ("Prüfwerte") of the German soil protection laws by a default factor of 2 or 3 in cases of soil contaminations older than 20 years.

Arsenic↗

PubMed2001

The effect of moisture and blood contamination on bond strength of a new orthodontic bonding material.

The practice of orthodontics often requires the bonding of brackets under difficult conditions of moisture and/or blood contamination. Transbond MIP (3M Unitek, Monrovia, Calif) is a hydrophilic primer designed to bond in moist conditions. This study evaluated the bond strength of Transbond MIP under dry, moist, and blood-contaminated conditions. Ninety human premolars were bonded in 3 equal groups with Transbond MIP after acid etching; the enamel surfaces were either dry, moist, or contaminated with human blood. The shear bond strength was recorded. Dry bonding resulted in a significantly higher bond strength (15.69 MPa) than moist (12.89 MPa) or blood-contaminated (11.16 MPa) bonds. However, all bond strengths were in excess of previous reports of required clinical bond strength, and it was concluded that Transbond MIP is a suitable adhesive for bonding in conditions of poor moisture control or blood contamination.

Acid Etching, Dental↗

PubMed2002

Bacterial contamination in postmortem bone donors.

We analyzed factors influencing the contamination rate of allografts and blood samples obtained from postmortem bone donors. 5,710 allografts were harvested, from 550 donors of which 3,164 (55%) were swab culture negative. Blood cultures were positive in 140 donors (26%). The risk of graft contamination increased with each extra team member (Odds Ratio 1.9). It was also higher with organisms of greater virulence in donors with a positive blood culture (OR 3.5). The risk of blood contamination increased per hour postmortem (OR 1.1) and the same increase was seen with organisms of high virulence. In donors with multiple trauma, the risk of blood contamination with organisms of high virulence was greater (OR 8.2), but smaller in donors with preceding organ procurement (OR 0.1). To minimize the bacterial load, donors should be obtained in operating rooms, using aseptic techniques with only a few personnel for procurement. The postmortem time should be kept to a minimum. The procurement cultures from donors with multiple trauma should be carefully interpreted. Blood cultures should be taken into account, since these can help to find contamination not detected by swab cultures.

Bacterial Infections↗

PubMed2003

Microbial cross-contamination by airborne dispersion and contagion during defeathering of poultry.

1. A readily identifiable strain of Escherichia coli K12 was used as a 'marker' organism to determine the sources, routes and patterns of microbial cross-contamination during mechanical defeathering of broiler chicken carcases. 2. Inoculation of scald water with the marker organism led to a relatively even pattern of carcase contamination during subsequent defeathering. Microbial cross-contamination was greater by this route of inoculation than by either surface inoculation of a 'seeder' carcase or oral inoculation of a live bird one day before slaughter. 3. Dispersal of the marker organism was strongly influenced by the mechanical action of the defeathering machines. Forward transmission of the marker occurred by aerosol or large airborne droplets and particulates such as feathers. Moving carcases through the defeathering machines when these were non-operational clearly reduced backward transmission of the marker. 4. Although microbial dispersal was unaffected by increasing the spacing between individual carcases or installing a water curtain at the entry and exit of the defeathering machines, shielding of carcases with aluminium baffles reduced counts of the marker organism from contaminated carcases by > 90%. 5. The results imply that microbial cross-contamination of broiler chicken carcases during defeathering occurs mainly via the airborne route, which could be contained by physical means.

Abattoirs↗

PubMed2003

Microbial contamination of artificially incubated Greater Rhea (Rhea americana) eggs.

1. This paper is a report of biological agents that contaminate Greater Rhea (Rhea americana) eggs during artificial incubation. 2. The cleanliness of eggs when collected, and the period of storage prior to incubation, were investigated to assess their effects on microbial contamination and hatchability. 3. A total of 14 bacteria and 4 fungi species were isolated within the egg in the laboratory. 4. Microbial contamination was higher (24%) in very dirty eggs than in eggs which were clean or dirty (16%). Hatching success was lower (30%) for very dirty eggs, compared with 42% for clean or dirty eggs. 5. The percentage of microbial contamination of stored eggs (10%) did not differ significantly from that of non-stored ones (5%). 6. The extreme lower and upper limits of infection rate estimated for artificially incubated Greater Rhea eggs were 4% and 40%, respectively, being higher than in poultry species. 7. It is concluded that collecting eggs soon after laying will reduce the risk of microbial contamination.

Animals↗

PubMed2001

Aflatoxin M1 contamination in commercial samples of milk and dairy products in Kuwait.

As part of the programme on monitoring of environmental contaminants in food stuff in Kuwait, 54 samples of fresh full cream and skimmed milk, powdered milk, yoghurt, and infant formula were analysed for aflatoxin M1 (AFM1) by HPLC following sample clean up using immuno-affinity columns. Of samples, 28% were contaminated with AFM1 with 6% being above the maximum permissible limit of 0.2 microgl(-1). Three fresh cow milk samples collected from a private local producer showed the highest level of 0.21 microg l(-1) AFM1. There was no contamination with AFM1 in powdered milk and infant formulas. These results show the necessity of a survey involving a larger number of milk and its products and suggest that presently the contamination of milk and milk products with AFM1 does not appear to be a serious health problem in Kuwait. Nevertheless, a continuous surveillance programme may be warranted to monitor regularly the occurrence of aflatoxins in the animal feeds responsible for current limited contamination and to note rapidly and worsening in the situation that may depend on market changes or on unfavourable climatic developments.

Aflatoxin M1↗

PubMed2003

A new technology for the treatment of mercury contaminated water and soils.

A new technology has been developed for the treatment of contaminated water and soils with lignin derivatives. It has been demonstrated that this technology can be used in the process of removal of high levels of mercury from water, and in the immobilization of leachable mercury in contaminated soils. Lignin derivatives contain an abundance of oxygen-containing functional groups such as phenolic, carboxyl, sulfonyl, alcoholic and enolic structures, which will form lignin-metal macromolecular complexes with high stability through ionic and coordinate covalent bonding. This feature is the basis for the application of lignin derivatives in the removal of metal contaminants from water and in the immobilization of leachable metal in soils or sediments. Tests have confirmed that lignin derivatives are capable of combining with a variety of metal ions including chromium, copper, lead, zinc, mercury, nickel and aluminum. In the new water treatment process, lignin derivatives are dissolved in mercury contaminated water to complex mercury in an exceptionally stable form of a lignin-mercury colloid. The lignin-mercury colloid is then coagulated through the addition of a flocculating agent such as ferric chloride. Under optimized conditions, a dean effluent is produced with a residual mercury level of less than 1 microg l(-1), together with a ferric sludge that is not leachable by TCLP, EPA Method 1311. In the new soil stabilization process, a new solid adsorbent of ferric-lignin is blended with mercury contaminated soil. This solid adsorbent can stabilize the soil by complexing with mercury and, thereby, greatly reduce the TCLP mercury of soil.

Adsorption↗