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PubMed1994

[Bacteria-reducing properties of copper-containing and non-copper-containing materials. II. Relationship between microbiocide effect of copper-containing materials and copper ion concentration after contamination with moist and dry hands].

The bactericide quality of different materials containing copper (copper, brass, brass-sheet) was tested and particularly the effect of humidity and copper-concentration was examined. In first examinations (I. communication) (19) the materials were contaminated by hands, which were dipped into a suspension of different microorganisms (Micrococcus luteus, Staphylococcus aureus, Enterococcus faecium, Escherichia coli, Enterobacter cloacae, Pseudomonas aeruginosa). The survival rate of the microorganisms on the surfaces was determined after defined exposure times (0, 5, 30, 60, 120 min). The following ways of contaminating the test materials were chosen: single contamination with wet hands, repeated contamination with wet and dry hands. In this examination the results were tested for statistical significance and in parallel experiments the copper-concentration on the surfaces of the materials was determined. Materials containing copper contaminated with wet hands show a significant bactericide effect after an exposure time of 120 min. The bactericide effect on Micrococcus luteus and Pseudomonas aeruginosa is inhibited after contamination with dry hands. This results can not be explained by a different copper-concentration on the surfaces of the materials, because a statistically significant difference of copper-ion concentrations between contamination with wet and dry hands could not be obtained.

Bacteria↗

PubMed1993

[Bacterial reducing qualities of copper-containing and non-copper-containing materials. I. Contamination and sedimentation in humid and dry conditions].

In this examination the bactericide qualities of different materials were tested. Particularly the effect of humidity was examined. 3 materials containing copper ("copper", "brass" and "brass sheet") and 2 materials not containing copper ("polyamide B" and "high-grade steel") were tested. The surfaces of the 5 types of material were contaminated with a suspension of 2 different bacteria species (Staphylococcus aureus and Micrococcus luteus). After defined exposure times the survival rate of the microorganisms on the surfaces was determined by the standardized method of the "Guidelines of the German Society of Hygiene and Microbiology". Additionally the sedimentation of airborne microorganisms on the materials was tested by determining the number of colony-forming-units after defined exposure times. In further examinations the materials were contaminated by hands, which were dipped into a suspension of different microorganisms (Micrococcus luteus, Staphylococcus aureus, Enterococcus faecium, Escherichia coli, Enterobacter cloacae and Pseudomonas aeruginosa). The following ways of contaminating the test materials were chosen: single contamination with wet hands, repeated contamination with wet and dry hands. After defined exposure times the survival rate of the microorganisms on the surfaces was determined. The results show, a bactericide quality of copper depends on the percent of copper-content of the tested materials, exposure time, humidity, frequency of contamination and bacteria species. Humidity and only single contamination cause a reduction of bacteria. Reduction of gram-negative bacteria is more easily than reduction of gram-positive bacteria. Enterococcus faecium shows the highest, Pseudomonas aeruginosa the lowest reduction rate of bacteria in the following sequence: Enterococcus faecium, Escherichia coli, Enterobacter cloacae, Micrococcus luteus, Staphylococcus aureus and Pseudomonas aeruginosa.

Air Microbiology↗

PubMed1996

Toxin occurrence time in relation to sensorial changes in meat cans contaminated with Clostridium botulinum type B endospores.

The study concerning dissemination and expansion of spore-forming rods and the possibility of botulinum toxin occurrence was performed on meat cans model contaminated experimentally with Clostridium botulinum type B366 toxigenic strain endospores. Meat cans were contaminated with the spore suspension of 4 x 10(3) spores per can and they were stored at 30 degrees C. Methodically visible toxigenicity (biological assay performed on white mice) took place in 84.3% cases by the time deformation of contaminated cans took place. When the first can bulging occurred almost 50% of contaminated cans were sensorially estimated as useful for consumption but almost 40% of them already contained toxin. In comparison to contaminated cans estimated sensorially as useful for consumption (in each experimental group) the percentage was established where the presence of toxin was determined as "consumer's risk". The mean value of those percentages was 76.4% for all experimental groups. In the studies on the vegetation dynamics and C. botulinum rods and toxin expansion in contaminated cans, we demonstrated the spore-forming rods dissemination, as well as limited range of toxin occurrence. Undertaken studies demonstrate that the process of toxigenicity often precede of accumulation of metabolic gases responsible for cans' deformation, as well as generation of visible sensorial changes which disqualified the contaminated cans for consumption.

Animals↗

PubMed1998

Bacterial contamination of autologous bone marrow: reinfusion of culture-positive grafts does not result in clinical sequelae during the posttransplantation course.

OBJECTIVES: Microbiological cultures and posttransplantation course were analyzed in order to investigate the incidence and clinical significance of bacterial contamination of autologous bone marrow (BM) grafts. METHODS: Cultures were obtained from BM after collection, BM concentrate after processing, contaminated/cryopreserved BM at thawing, and from peripheral blood (PB) following autologous BM transplantation (ABMT). The posttransplantation course of patients grafted with culture-positive BM was recorded and compared with patients who underwent ABMT with noncontaminated BM grafts. RESULTS: In 239 BM grafts processed, the incidence of microbiological contamination was 26.4% (n = 63). Fifty marrow grafts were contaminated by bacteria from the skin flora: coagulase-negative Staphylococcus (CNSC), Propionibacterium, and Corynebacterium species (79%). Thirty-eight patients underwent ABMT (day 0) with cryopreserved culture-positive BM, and 32 patients were evaluable for microbiological cultures at thawing: in 10 of 32 BM grafts CNSC was found prior to reinfusion. Following ABMT, PB cultures revealed CNSC in 5 of 38 patients between days +4 and +12. However, the late occurrence of positive PB cultures after BM reinfusion made a relationship between BM CNSC and PB CNSC unlikely. In 33 of 38 patients, no graft-contaminating bacteria were detected in PB. Comparison of the posttransplantation course of patients who received contaminated BM with that of patients grafted with noncontaminated BM showed no significant differences concerning time to engraftment, febrile days, and days on antibiotics. CONCLUSION: (1) Collection and/or ex vivo processing can result in microbiological contamination of BM grafts predominantly with bacteria from the skin flora, and (2) only CNSC can be cultured at thawing from previously contaminated/cryopreserved BM. Since patients undergoing ABMT usually receive oral antibiotics from beginning of the conditioning regimen which are active against CNSC, no further administration of antibiotics is recommended for the reinfusion of bacterially contaminated BM grafts.

Adolescent↗

PubMed1998

Technetium-99m DTPA aerosol contamination in lung ventilation studies.

UNLABELLED: Contamination of working areas by 99mTc DTPA aerosol is of concern to nuclear medicine technologists. This study sought to determine the extent of 99mTc DTPA contamination to technologists, and to localize sources of aerosol leakage so that methods could be identified that would minimize contamination. METHODS: Fifty to eighty millicuries 99mTc DTPA, diluted to a volume of 4-5 ml with normal saline, were injected into the nebulizing chamber of two commercially available inhalation aerosol systems. The patient's nostrils were clamped and a damp washcloth was wrapped around the patient's mouth. An alcohol swab was placed in the exit port of the exhaust filter in each delivery system, and the technologist involved wore a face mask during the inhalation phase. The patient breathed DTPA-labeled aerosol by mouth until the counting rate in the lungs was four times greater than the counting rate from the pulmonary perfusion phase. Connecting joints of the delivery system were then wipe tested. Last, a Geiger-Mueller detector (pancake probe) was used to survey all device components. Readings above 0.05 mR/hr were considered contaminated. RESULTS: The patient was the greatest source of leakage as determined by the damp washcloth, followed by the joints of the tubes of the delivery system and, finally, the system's exhaust filter. Contamination readings from face masks worn by technical personnel during the lung ventilation studies were slightly greater than 0.05 mR/hr. CONCLUSION: The findings support trace levels of contamination to both the technologist and room while performing 99mTc DTPA aerosol ventilation studies. Comparative data using the two delivery systems revealed little difference in sources of leakage and little variation in contamination measurements.

Aerosols↗

PubMed2004

Mould contamination in production of semi-hard cheese.

Air, equipment, plastic film, brine and milk were sampled from four cheese factories in Norway during the period September 1997 to May 1999 in order to identify the critical points for mould contamination in the production process. Altogether, 672 samples were collected. Penicillium brevicompactum was the most frequently isolated species from three of the factories, while Geotrichum candidum was the most frequently isolated species from the fourth. P. commune, P. palitans, P. solitum and P. roqueforti ss. roqueforti, all common contaminants on cheese, were found in samples of air and equipment, and the former was also isolated from plastic film. The results in the present study showed that the mould levels in the cheese factories varied between the different control points. The mould levels at some of the air control points had high mould counts while the mould levels in milk and brine, on equipment and on plastic film, generally were low. The fungi at the control points with high mould levels consisted of common cheese contaminants as well as species not commonly isolated from cheese. The statistical analysis showed that air was the major source of the important cheese contaminants P. commune and P. palitans during the production process. High quality air with low number of cheese contaminants in production rooms, especially the wrapping room, is important in order to reduce mould contamination.

Air Microbiology↗

PubMed2002

Prospective study of the incidence and complications of bacterial contamination of enteral feeding in neonates.

PURPOSE: The goal of this study was to determine incidence of, and complications resulting from, bacterial contamination of enteral feedings in neonates. METHODS: A prospective study of 50 tube-fed neonates was conducted. Infants were bolus fed via an open gravity drained system; demographic and clinical data were gathered. The lumen of the tube was cultured quantitatively after 7 days. All organisms were isolated, identified, frozen, and stored to correlate with clinical cultures. RESULTS: The 50 neonates were fed for a mean of 17.6 days each and represent 125 patient weeks (1 tube per patient per week). A total of 71 of 125 tubes were "contaminated" (>1,000 colony forming units [CFU]/mL), with a mean 908,173 CFU and 3 different bacteria types. Among formula-fed infants, feeding intolerance occurred in 24 of 32 weeks with contaminated tubes versus 0 of 44 weeks with noncontaminated tubes (P <.05). Contamination occurred in 41 of 48 weeks in patients on H2 antagonists versus 32 of 66 weeks in patients with normal gastric acidity (P <.05). Necrotizing enterocolitis developed in 7 patients; all were fed formula contaminated with greater than 100,000 CFU/mL of Gram-negative bacteria. Four required operation; intraoperative cultures found the same organism as cultured previously in the tube in all 4 infants. CONCLUSION: Bacterial contamination of enteral feeding occurs frequently, causes significant feeding intolerance, and may contribute to NEC.

Bacterial Infections↗

PubMed1993

The effect of skin disinfection materials on reducing blood culture contamination.

Contaminated blood cultures may cause results to be misinterpreted, create unnecessary work for the laboratory, and increase costs. Disinfection of the venipuncture site is considered to be necessary for preventing contamination, although there is little information about the effectiveness of using different disinfection materials. The use of 70% isopropyl pads and povidone iodine saturated swabs (conventional method) was compared with the use of a 70% isopropyl/10% acetone scrub and povidone iodine dispenser (PREP method) for skin disinfection. Blood culture "kits" were prepared--bags containing collection tubes, instructions, and either conventional or PREP materials and were distributed randomly. The contents were concealed by a cover to prevent the user from selecting a specific type of decontamination kit. The kits were identified in the laboratory by color-coded labels on the collection tubes. Among 1,546 specimens evaluated, the contamination rate observed with conventional disinfection was significantly higher (4.6%; N = 763) than with PREP materials (2.2%; N = 783, P = 0.011) and was equivalent to the preceding 6-month contamination rate (4.7%). The lower contamination rate may be associated with greater effectiveness of a scrub or isopropyl/acetone solution, or both. Decontamination materials may have a significant impact on reducing blood culture contaminants from skin flora.

1-Propanol↗

PubMedDate not supplied

Analysis of sites of bacterial contamination in an enteral feeding system.

BACKGROUND: Contamination of enteral feedings is an often overlooked source for bacterial infection in the intensive care unit. A new 1-L enteral feeding system with minimal chances of touching critical areas (Nutrison Pack) was compared with routinely used 0.5-L glass bottle systems. METHODS: Patients admitted to intensive care were randomized to Pack or glass bottle feeding systems. Cultures were taken from the delivery sets 5 times during the day and from feeding containers and different sites of the system after 24 hours. RESULTS: Bacteria were present in 3 of 112 glass bottles and in 2 of 95 Pack bags. True bacterial contamination (defined as >10(2) colony-forming units/mL, with same bacteria also present in the delivery set) was found in none of the Packs with a 12-h (69 Packs) or a 24-h (26 Packs) hanging time and in only 1 of the glass bottles with a hanging time of 24 hours, which exceeded the advised hanging time of 8 hours. In contrast, the contamination rate of delivery sets was 48%, with increasing bacterial counts over the day and 4 subsequent days. Bacteria mainly belonged to the group of potentially pathogenic bacteria (Enterobacteriaceae and Pseudomonaceae). They likely originated from throat, lungs, and stomach and grew into and along feeding tubes upwards until they reached the delivery set. CONCLUSIONS: Prolonged hanging times of Pack bags were safe with respect to bacterial contamination. However, the bacterial safety of enteral feedings is more likely to be endangered by the endogenous route of contamination rather than exogenous contamination, as high bacterial counts were found in feeding tubes and delivery sets as a result of retrograde growth.

APACHE↗

PubMed2000

Evaluation of vaccines, interferons and cell substrates for pestivirus contamination.

Pestiviruses are potential contaminants of biological products produced in bovine or porcine cells or manufactured via processes using animal-derived raw materials such as bovine serum. In order to investigate possible contamination of products including those manufactured and/or licensed in the US, 38 lots of viral vaccines and five lots of interferon alpha (IFNalpha) were tested by reverse transcriptase polymerase chain reaction (RT-PCR) for the presence of bovine viral diarrhoea virus (BVDV). All vaccines and interferons were negative for contaminating BVDV RNA when tested by RT-PCR, with the exception of an experimental live viral vaccine that had been produced in BVDV contaminated rabbit kidney cells. Cell lines commonly used to produce biological products and vaccines were experimentally infected with the NADL strain of BVDV to determine if they were permissive for virus replication. MRC-5 and WI-38 cells were not infected. In contrast, Vero, CHO and CEF cells showed evidence of pestivirus infection. Taken together these data suggested that currently licensed viral vaccines were unlikely to be contaminated with pestiviruses. However, cell banks derived from non-human primate, hamster or rabbit kidney cell lines, or cultures of primary chick embryo fibroblasts, may be infected with BVDV if exposed to pestivirus contaminated raw materials during manufacture.

Animals↗

PubMed1999

Fish consumption and contaminant exposure among Montreal-area sportfishers: pilot study.

A 1995 pilot study assessed sport fish consumption and contaminant exposure among Montreal-area residents fishing the frozen St. Lawrence River. Interviews conducted among 223 ice fishers met on-site were used to create an index of estimated exposure to fish-borne contaminants. A second-stage assessment of sport fish consumption and tissue contaminant burdens included 25 interviewees at the highest level of estimated contaminant exposure (of 38, or 66% of those solicited) and 15 low-exposure fishers (of 41, or 37% of those solicited). High-level fisher-consumers reported eating 0. 92+/-0.99 sport fish meals/week during the previous 3 weeks compared to 0.38+/-0.21 (P<0.05) for the low-level group. Based on the product of consumption frequency times mass of sport fish meals consumed, high-level consumers ate a mean of 18.3 kg of sport fish annually versus 3.3 kg for the low-level consumers. Tissue contaminant assessments showed significant (P<0.05) groupwise differences: 0-1 cm hair mercury (median 0.73 microgram/g for the high versus 0.23 microgram/g for the low group), lipid-adjusted plasma PCB congeners (Aroclor 1260: median 0.77 microgram/g versus 0.47 microgram/g), and lipid-adjusted plasma DDE (median 0.35 microgram/g versus 0.26 microgram/g). No participant had a hair mercury or plasma DDE concentration above Health Canada recommendations but 2/25 high-level participants (8%) had plasma Aroclor 1260 concentrations above recommended limits. The results of this pilot study suggest that a small number of Montreal-area sportfishers consume their catch as often as three times weekly and that those consuming sport fish frequently have significantly higher tissue levels of mercury, PCBs, and DDE than do infrequent consumers. On the other hand, compared to other groups in Quebec, such as the Inuit or commercial fishers on the North Shore of the Gulf of St. Lawrence, Montreal-area sportfishers eat less fish and have lower tissue concentrations of fish-related contaminants.

Adult↗

PubMed1998

Dietary and tissue residue analysis and contaminant intake estimations in rats consuming diets composed of Great Lakes salmon: a multigeneration study.

To further characterize the toxicological risk associated with chemical contaminants in Great Lakes fish, a multigeneration rat reproduction study was designed. Mature chinook salmon (Oncorhynchus tsawytscha), collected during the Fall 1991 spawning runs from Sydenham River, Lake Huron, and Credit River, Lake Ontario, were filleted, lyophilized, and incorporated into standard rat diets at 25% (w/w) or 100% (w/w) of the normal protein compliment [casein, 20% (w/w)]. This resulted in diets composed of 5 or 20% (w/w) lyophilized fish and estimated daily fish intakes by the rats at levels approximately 15- and 60-fold greater, respectively, than the current estimate for the Canadian public for all fish and seafood. Both fresh and lyophilized fish were analyzed for the following groups of contaminants: halogenated aromatic hydrocarbons [polychlorinated biphenyls, dibenzodioxins, and dibenzofurans (PCBs, PCDDs, PCDFs)], polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides, metals, volatile organics, and other extractable organics (chlorinated phenols and benzenes). In general, only minor site differences existed for the specific types of contaminants detected; however, fish from the Credit River contained slightly greater amounts of PCBs (2- to 3-fold), dioxin toxic equivalencies (TCDD TEQs; 1.5- to 2.0-fold), DDT and metabolites (1. 5-fold), and appreciably higher amounts of mirex (15-fold). This general pattern of contaminant differences continued when the various diets were prepared using the lyophilized fish. Tissue samples (adipose, liver) were taken from the animals at various stages of the study and also analyzed for the same groups of contaminants. In general, adipose tissue was the major reservoir for organochlorine (OC) pesticides and PCBs, while "dioxin-like" PCDD/DF congeners and mercury were found preferentially in the liver. Contaminant intake calculations and tissue residue levels are provided.

Adipose Tissue↗

PubMed1993

Contaminants in L-tryptophan associated with eosinophilia myalgia syndrome.

In late 1989, an epidemic of eosinophilia-myalgia syndrome (EMS) that resulted in several thousand cases of the syndrome and 36 deaths was recognized in the United States. Physicians in New Mexico linked the epidemic to the ingestion of L-tryptophan (LT). Results of studies indicated that one or more trace contaminants in LT were likely causes of the EMS epidemic. Investigators traced the LT that was taken by most patients with EMS to a single manufacturer, Showa Denko K.K. of Japan. We now report results of high performance liquid chromatographic analysis of LT samples from this manufacturer. Three sets of blind-coded samples were analyzed: the priority case lot set, which included 54 case-associated LT lots and 50 noncase-associated LT lots that were taken by case and control subjects who used only one brand of LT; the single lot case set, which included 73 case-associated LT lots and 25 noncase associated LT lots taken by case and control subjects who used only a single lot of LT; and the South Carolina tablet set, which included LT tablets taken by case subjects (n = 26) and by control subjects (n = 52). We statistically compared the concentration of each contaminant in case-associated, noncase-associated, and control samples of each sample set. The analyses showed that there were more than 60 minor contaminants in the LT from Showa Denko K.K., and that six of these contaminants were associated with EMS. The structures of three contaminants are known, but the identities of the other three contaminants are currently unknown.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacillus↗

PubMed1999

Contamination susceptibility of three needleless and one standard needle injection systems.

PURPOSE: To compare in vitro the contamination susceptibility of three needleless and one standard needle injection systems. METHODS: The Baxter InterLink, St. Paul Medical Key-Lok, Braun SafSite, and Becton Dickinson heparin lock, were compared. Fifty of each were studied. Each system was connected to a culture bottle and injected 30 times over 72 hr. The manufacturers' directions were followed except for Braun's, which recommend that a new sterile cap be used after each injection. Instead, the same cap was used after each injection to reflect day-to-day clinical practice. Culture bottles were subsequently analyzed for bacterial growth. RESULTS: The contamination rates for the heparin lock, InterLink, Key-Lok, and SafSite were 3/50 (6%), 6/50 (12%), 4/50 (8%), and 36/50 (72%), respectively. All positive cultures grew coagulase-negative staphylococcus species. There was no difference in contamination rates between the InterLink, Key-Lok, and heparin lock designs. The contamination rate of the SafSite was higher (P < 0.001) than the other three systems. CONCLUSIONS: The InterLink and Key-Lok systems had a similarly low contamination susceptibility as a standard needle injection system. It was not clear if the high contamination rate found with the SafSite system was due to non-adherence to the manufacturer's directions for handling.

Bacteria↗

PubMedDate not supplied

Iodine contamination as a cause of hyperthyroidism or lack of TSH response to TRH stimulation (results based on a screening investigation).

The sera of all patients with completely suppressed TSH response to TRH obtained during one year (n = 668), and of those with diminished TSH response (n = 153) were screened for total serum iodine content. The ratio between serum iodine and thyroxine iodine below 1.5 indicates none or only a minor degree of iodine contamination, whereas a ratio above 1.5 is a clear index of exogenous iodine contamination. Eighty-four (21.3%) of 395 patients with overt hyperthyroidism were iodine contaminated. No prevalence of hyperthyroidism with hyperthyroxinemia could be detected as compared to T3-hyperthyroidism in the contaminated groups. Surprisingly, the iodine contamination rate was twice as high in 273 patients with suppressed TSH response to TRH but normal thyroid hormone levels and not fully explained thyroidal diseases. A high incidence of multifocal autonomous adenomas of the thyroid is the most probable explanation for the TSH suppression in iodine contaminated patients with normal thyroid hormone levels.

Angiocardiography↗

PubMed2004

[Chemical food contaminants].

Chemical food contaminants are substances which are neither present naturally in the usual raw material used for food production nor are added during the regular production process. Examples are environmental pollutants or contaminants derived from agricultural production of crops or livestock or from inadequate manufacturing of the food product itself. More difficult is the classification of those compounds formed during regular manufacturing such as products of thermal processes including flavoring substances. In these cases, it is common practice to call those compounds contaminants which are known for their adverse effects such as acrylamide, whereas constituents which add to the food-specific flavor such as Maillard products formed during roasting, baking etc. are not termed contaminants. From a toxicological viewpoint this distinction is not always clear-cut. Important groups of chemical contaminants are metals such as mercury or lead, persistent organic pollutants such as polychlorinated biphenyls and related pollutants, which are regularly found in certain types of food originating from background levels of these compounds in our environment. Furthermore, natural toxins form microorganisms or plants, and compounds formed during thermal treatment of food are of major interest. In general, a scientific risk assessment has to be carried out for any known contaminant. This comprises an exposure analysis and a toxicological and epidemiological assessment. On these grounds, regulatory and/or technological measures can often improve the situation. Major conditions for a scientific risk assessment and a successful implementation of regulations are highly developed food quality control, food toxicology and nutritional epidemiology.

Consumer Product Safety↗

PubMed2000

[Sterilization of phacoemulsification and vitrectomy instruments. Contamination and evaluation].

BACKGROUND: Contamination of automated surgical equipment is widely disregarded as a potential source of perioperative infection. We investigated the possibility of contamination of the aspiration fluid by the vacuum control manifold (VCM). The normal, unsterile internal VCM was compared with a modified external VCM that was regularly disinfected. MATERIALS AND METHODS: We investigated 37 aspiration fluid specimens from routine cataract and vitrectomy operations performed with automated evacuation systems. There were 25 specimens from three automated evacuation systems equipped with an internal VCM (experimental groups) and 12 specimens from one system equipped with a modified external VCM (control group). No hygiene procedures were used with the hidden internal VCM, but the modified external VCM was regularly rinsed and filled with 70% isopropanol overnight. Specimens were collected under sterile conditions, centrifuged, cultured for bacterial growth on blood agar and MacConkey agar for 24-48 h at 37 degrees C, and analyzed microbiologically. RESULTS: Aspiration fluids of irrigation/aspiration systems used for intraocular surgery were found to be severely contaminated with bacteria originating from the VCM. In all aspiration fluid specimens from internal VCM systems, 2(+)-4+ bacterial growth was found. Stenotrophomonas maltophilia (17), Comamonas acidovorans (8), and Agrobacterium radiobacter (13) were found most frequently. All specimens from the modified external VCM system remained sterile. There was a significant difference with regard to the frequency of contamination of the aspiration fluid between experimental and control groups (P = 0.0001, chi 2). CONCLUSIONS: We found that the aspiration fluid of common phaco- and vitrectomy systems was strongly contaminated by bacteria originating from the internal VCM. The technical modification of an external VCM allows easy disinfection and prevents contamination of the aspiration fluid.

Bacteriological Techniques↗

PubMed2004

Experimental confirmation of Serratia marcescens contamination in multiple-dose vials of heparin-saline solution.

The initial contamination of heparin-saline solution (HS) in multiple-dose vials (MDVs) by Serratia marcescens was experimentally investigated using various isolates. Isolates I2 and S1 were from blood specimens from patients with a hospital-acquired infection (HAI). Isolates I13 and FHSM9043 were from urine and blood specimens, respectively, from patients without HAI. Isolate I124, with a pulsed-field get electrophoresis pattern identical to that of isolate I2, was from the hospital environment. Viable cells of isolate I2 were carried over into the HS of MDVs when the contaminated rubber septum was pierced with a syringe needle. When the outside surface of the septum was contaminated by inoculating it with wet-cell suspensions in HS or Müller-Hinton broth, the viable cells carried over were detected at a minimum inoculum size (MIS) of 10(3) s cfu/ml. However, when the surface was contaminated by inoculating it with dry-cell suspensions, the viable cells carried over were detected at an MIS of 10(7) s cfu/ml. The viable cells in the internal lumen of the needle much more than those on its outside surface spread to the HS of MDVs. For exposures of 24 h and 72 h at 4 degrees C to HS with 1% benzyl alcohol as a preservative in MDVs, viable cells of all isolates tested were detected at MIS values of 1 s and 10 s cfu/ml, respectively, increases three orders of magnitude smaller than those of reference strain IFO3736. These results suggest that S. marcescens isolates are readily carried over into the HS of MDVs by piercing a wet, contaminated rubber septum with a syringe needle. Also, despite the sterilization action of 1% benzyl alcohol, the organism persistently survived at 4 degrees C, even when initial contamination was with a small amount of inoculum.

Bacteremia↗