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PubMed2006

Evolution of surveillance methods for detection of bacterial contamination of platelets in a university hospital, 1991 through 2004.

BACKGROUND: Platelet (PLT) bacterial contamination (PBC) is the most common transfusion-associated infection. It is important to understand the impact of interventions addressing this problem. STUDY DESIGN AND METHODS: PBC was studied by prospective (active) and transfusion-reaction triggered (passive) surveillance from July 1991 to December 2004. Active surveillance, utilized for 10 years, included bacterial culture of all or 4- and 5-day-old PLTs at issue and intermittent use of Gram stain, pH measurements, and early (24-hr) culture of single-donor plateletpheresis (SDP) units. RESULTS: Active surveillance detected 38 instances of PBC, 7 in SDP units (1:2213) and 31 in random-donor PLT units (1:2090 units, p = 0.89; or 1:418 pools of 5 units, p < 0.001). Contaminants were coagulase-negative staphylococci (CONS; n = 27), Staphylococcus aureus (4), Bacillus cereus (1), Serratia marcescens (2), streptococci (2 S. bovis, 1 S. uberis), and CONS with viridans group streptococcus (1). Only one instance of contamination, caused by Pseudomonas aeruginosa, was detected by passive surveillance, with fatal outcome. Colony counts of contaminants ranged from 0.5 x 10(2) to 4 x 10(11) colony-forming units per mL at time of issue. PBC was interdicted before transfusion in 6 cases through Gram stain screening. Transfusion reactions occurred in 13 of 32 recipients (41%), with 9 severe reactions (28%) and 3 deaths (9%). pH testing failed to detect 5 contaminated units and resulted in discard of nearly 2 percent of units, whereas culture of SDP units at 24 hours failed to identify a contaminated unit. CONCLUSION: Improved active surveillance methods for detecting PBC are needed to improve the safety of PLT transfusions.

Bacterial Infections↗

PubMed1998

Contamination of the turbine air chamber: a risk of cross infection.

In the present work, we evaluated (a) the influx of contaminating fluid into the air chamber when a high-speed turbine stops rotating, (b) the significance of a series of variables (type of handpiece and dental unit, shape of the bur, number of stops set on the turbine) which condition it, and (c) the time required to expel the contaminating fluid from the turbine head. Results showed that contamination takes place every time the turbine stops rotating with the bur in contact with an external fluid. The main variable affecting the influx of contaminating fluid into the air chamber of the turbine head was represented by the shape of the bur (F=54.9; p<0.01). Another significant variable was the type of handpiece and dental unit (F=7.3; p<0.01). The number of stops set on the turbine was irrelevant (F=0.03; p=n.s.). The expulsion of the contaminant from the turbine head showed 2 different exponential rates: a very rapid-elimination phase within 30 s and a slow-elimination phase between 60 and 300 s. In order to remove over 99% of the contaminant from the air chamber, a turbine had to run for more than 4-7 min depending on the type of the handpiece. In conclusion, data from the present study suggest that a significant cross-infection potential exists with high-speed handpieces whenever they are only externally scrubbed and disinfected so the internal cleaning and sterilization between patients is mandatory. The practice of flushing by running the turbines between patients should be discouraged.

Air↗

PubMed2002

Comparison of four antiseptic preparations for skin in the prevention of contamination of percutaneously drawn blood cultures: a randomized trial.

A number of skin antiseptics have been used to prevent the contamination of blood cultures, but the comparative efficacies of these agents have not been extensively evaluated. We therefore sought to compare the efficacy of four skin antiseptics in preventing blood culture contamination in a randomized, crossover, investigator-blinded study conducted in an emergency department and the inpatient wards of a university hospital. The patient group included all patients from whom blood samples were obtained percutaneously for culture. Skin antisepsis was performed with 10% povidone-iodine, 70% isopropyl alcohol, tincture of iodine, or povidone-iodine with 70% ethyl alcohol (i.e., Persist). The blood culture contamination rate associated with each antiseptic was then determined. A total of 333 (2.62%) of 12,692 blood cultures were contaminated during the study period compared to 413 (3.21%) of 12,859 blood cultures obtained during the previous 12-month period (relative risk = 0.82; 95% confidence interval, 0.71 to 0.94; P = 0.006). During the study, the contamination rates were determined to be 2.93% with povidone-iodine, 2.58% with tincture of iodine, 2.50% with isopropyl alcohol, and 2.46% with Persist (P = 0.62). We detected no significant differences in the blood culture contamination rates among these four antiseptics, although there was some evidence suggesting greater efficacy among the alcohol-containing antiseptics. Among the evaluated antiseptics, isopropyl alcohol may be the optimal antiseptic for use prior to obtaining blood for culture, given its convenience, low cost, and tolerability.

2-Propanol↗

PubMed1998

New polyether sulfone dialyzers attenuate passage of cytokine-inducing substances from pseudomonas aeruginosa contaminated dialysate.

The use of bicarbonate dialysate and high-flux and reprocessed dialyzers has raised concerns about the reverse transfer of dialysate contaminants into the blood compartment. This in vitro study was performed to investigate the reverse transfer of soluble Pseudomonas aeruginosa bacterial products across a polyether sulfone (PES), a newly developed synthetic polymer dialyzer. In vitro dialysis was carried out at 37 degreesC in a closed countercurrent recirculating loop dialysis circuit with a new PES dialyzer. An equal mixture of heparinized whole blood (from healthy volunteers) with pyrogen-free tissue culture medium was circulated in the blood compartment, and bicarbonate dialysate was circulated in the dialysate compartment. After 15 min of dialysis, the dialysate was challenged sequentially with 10(-4), 10(-3), and 10(-2) dilutions of a P. aeruginosa culture supernatant. 1-ml samples were drawn from the blood compartment 5 and 15 min after each challenge and incubated upright at 37 degrees C. At the end of 24 h, Triton X-100 was added, in order to extract total interleukin (IL) 6 and IL-8 production by the whole-blood mixture. These cytokines were measured by electrochemiluminescence assays. At dilutions of 10(-4) and 10(-3), the reverse transfer of soluble bacterial products across the dialyzer was negligible. Five and 15 min after contaminating the dialysate with the highest concentration (10(-2) dilution), the increase in IL-6 production was 239 +/- 170% (p = 0.06) and 886 +/- 444% (p = 0.02), respectively. However, comparing the IL-6-inducing potency of the 10(-2) bacterial supernatant dilution to the spontaneous IL-6 production in the blood compartment during dialysis with the same dilution of dialysate contaminant, there was a dramatic reduction in IL-6 production by 94 and 89% at 5 and 15 min, respectively. Similarly, 5 and 15 min after contaminating the dialysate with the 10(-2) dilution, the increase in IL-8 production was 357 +/- 147% (p = 0.07) and 630 +/- 229% (p = 0.04), respectively. However, comparing the IL-8-inducing potency of the 10(-2) bacterial supernatant dilution to the spontaneous IL-8 production in the blood compartment during dialysis with the same dilution of dialysate contaminant, there was a dramatic reduction in IL-8 production by 93 and 92% at 5 and 15 min, respectively. These results demonstrate that PES dialyzers markedly attenuate passage of cytokine-inducing substances from contaminated dialysate, using a method that detects the entire cytokine synthetic output in the blood compartment.

Bacteriological Techniques↗

PubMedDate not supplied

The incidence and clinical significance of intravenous fat emulsion contamination during infusion.

So that the actual contamination rate of intravenous fat emulsions, as well as the type of microbial contamination, could be quantified, 103 bottles of 10% fat emulsion were collected near infusion completion from patients' bedsides. All samples were cultured and compared according to actual hanging time, in addition to the amount and type of microbial contamination. Recovered organisms included Escherichia coli, Staphylococcus epidermidis, diphtheroids, and Micrococcus. Sample analysis failed to demonstrate significant differences in extrinsic microbial contamination rate or organism multiplication between samples infusing for less than or equal to 12 hr and those infusing longer. Although these products support microbial growth, the contaminants introduced into the infusate by environmental or touch contamination yielded minimal colony growth. No patient developed signs or symptoms of bacteremia during the study period. Therefore, infusion of intravenous fat emulsion products over extended periods of time in this study did not increase the risk of developing infectious complications.

Drug Contamination↗

PubMedDate not supplied

Contaminated enteral nutrition solutions as a cause of nosocomial bloodstream infection: a study using plasmid fingerprinting.

In July 1984, two patients fed enteral nutrition solutions contaminated with Enterobacter cloacae developed nosocomial bacteremia. Despite careful review of the preparation procedures as well as repeated microbiological surveys, 83 (27%) of the 309 formula bottles tested over a 1-yr period were contaminated and the source of contamination remained unknown. E. cloacae was the most frequent organism isolated (34%). The plasmid profiles of E. cloacae recovered from enteral nutrition solutions remained identical for several months. Blood culture isolates from 10 of the 40 patients who had developed E. cloacae nosocomial sepsis over a 7-yr period (1979-1985) had plasmid profiles linking them to contaminated enteral nutrition solutions. Epidemiological data from a case control study revealed that these 10 patients were indeed more likely to be exposed to enteral nutrition than the 30 others: 9/10 vs 10/30 (odds ratio 18, p = 0.002). Similarly, two of seven nosocomial Klebsiella pneumoniae bacteremias over a 6-month period in 1986 could be ascribed to administration of contaminated enteral liquid feeds prompting a general policy for using sterile commercially prepared solutions. Our results suggest that contaminated enteral nutrition solutions represent a significant cause of nosocomial sepsis.

Adult↗

PubMed1998

Contamination of propofol infusions in the intensive care unit: incidence and clinical significance.

Epidemics of bacteraemia and wound infection have been associated with the infusion of bacterially contaminated propofol administered during anaesthesia. We conducted an observational study to determine the incidence and clinical significance of administration of potentially contaminated propofol to patients in an ICU setting. One hundred patients received a total of 302 infusions of propofol. Eighteen episodes of possible contamination of propofol syringes were identified, but in all cases contamination was by a low-grade virulence pathogen. There were no episodes of clinical infection or colonization which could be attributed to the administration of contaminated propofol. During the routine use of propofol to provide sedation in ICU patients the risk of nosocomial infection secondary to contamination of propofol is extremely low.

APACHE↗

PubMed1993

Contamination study of multiple-dose vials.

OBJECTIVE: To document the number of opened, dated, and expired multiple-dose vials (MDVs) in patient-care areas and to determine what proportion of MDVs were contaminated with bacteria or cellular debris. DESIGN: Every tenth opened MDV (69/656) identified on the wards was collected, ensuring representation from each nursing unit. Contents were examined for contamination. SETTING: Medical-school-affiliated, tertiary care center. MAIN OUTCOME MEASURES: (1) Visual inspection for debris, medication type, location, lot number, manufacturer's expiration date, and date of opening; (2) culture in solid and broth media for bacterial growth; and (3) staining and microscopic examination for cellular constituents. RESULTS: No vials had been dated after opening and 4.6 percent were expired according to the manufacturer's expiration date. No bacterial contamination was evident; however, one vial was contaminated with red blood cells. CONCLUSIONS: Transmission of infection via contaminated MDVs has been well documented and contamination with red blood cells raises concerns about potential for transmission of bloodborne pathogens. Recommendations include dating MDVs after opening, emphasizing the need for proper aseptic technique, and discarding MDVs on the manufacture's date of expiration.

Drug Contamination↗

PubMedDate not supplied

Potential for microbial contamination of ADD-Vantage admixtures.

OBJECTIVE: To test for potential bacterial contamination of the ADD-Vantage system when the components are assembled in various hospital environments. STUDY DESIGN: One hundred fifty ADD-Vantage units were assembled by three different people in three separate locations within a hospital. Each person assembled ten units per day; the study spanned five days. After 72 hours of incubation, units were inspected for evidence of contamination. SETTING: ADD-Vantage units were assembled by a pharmacist in a laminar-flow hood, a pharmacy student using the pharmacy counter, and a nurse at a patient's bedside table. Personnel at each site wore their regular work attire. Each person observed handwashing techniques normally used during routine working hours. DATA EXTRACTION: Positive results were sent to the hospital microbiology laboratory for determination of growth type. RESULTS: After 72 hours, none of the systems exhibited microbial growth on visual inspection. No differences in microbial contamination of the ADD-Vantage systems relative to assembly site, day of assembly, or person performing the assembly were observed. The incidence of contamination was calculated at less than seven percent. CONCLUSIONS: There is minimal risk of bacterial contamination when ADD-Vantage systems are compounded either on a pharmacy counter or at a patient's bedside. Larger samples must be studied in order to detect differences in the incidence of contamination among assembly sites.

Cimetidine↗

PubMed1997

Microbial contamination of antiseptic-soaked cotton balls.

We investigated microbial contamination of in-use antiseptics at a hospital. No microbial contamination was observed in 70 samples of 0.02% benzalkonium chloride solution (500-ml volume), 70 samples of 1% titratable I2 povidone-iodine solution (250-ml volume), or 15 samples of 0.1% ethacridine lactate solution (500-ml volume) during use in reduced amounts. Nor was any microbial contamination observed in 70 samples of cotton balls soaked in 1% titratable I2 povidone-iodine solution in canisters or cotton gauze soaked in 70% (w/v) ethanol solution in canisters. However, among 70 samples of cotton balls soaked in 0.02% benzalkonium chloride solution in canisters, 6 (8.6%) were contaminated with 10(4) to 10(6) viable cells/ml. The microbial species detected were glucose non-fermentative bacilli such as Alcaligenes xylosoxidans and Pseudomonas putida. The contaminants obtained from cotton balls soaked in 0.02% benzalkonium chloride solution did not proliferate in that solution or in distilled water but showed rapid growth in the cotton balls soaked in either of these liquids. These findings suggested that benzalkonium chloride solution tends to become contaminated when cotton balls are immersed. Therefore, cotton balls soaked in benzalkonium chloride solution are not recommended as an antiseptic. When no other choice is available, the cotton balls should be soaked in benzalkonium chloride solution at the time of usage.

Alcaligenes↗

PubMed2006

Microbial contamination of nebulization solution and its measures.

We evaluated the microbial contamination of nebulization solutions in medication cups from a total of 76 ultrasonic nebulizers in use in 10 hospitals. In addition, an interview survey was given to nurses to evaluate the disinfection methods of these ultrasonic nebulizers. Of a total of 76 nebulization solution samples, 11 (14.5%) were contaminated with 10-10(2) colony-forming units (CFU)/ml and 9 (11.8%) with 10(3)-10(5) CFU/ml. The major contaminants were glucose non-fermentative bacilli such as Burkholderia cepacia, CDC gr.IV C-2, and Sphingomonas paucimobilis. Comparison of microbial contamination between the frequencies of disinfection showed a significantly lower number of contaminated samples when the cups were disinfected once daily than when disinfected once at intervals of 2-7 d (p=0.00037). In addition, comparison between the presence and absence of preservatives contained in the nebulization solution showed a significantly lower number of contaminated samples in the presence, rather than in the absence, of preservatives (p=0.00001). These results show that disinfection of ultrasonic nebulizers at 24-h intervals is desirable. In particular, when nebulization solutions not containing preservatives are used, disinfection at 24-h intervals is indispensable.

Bacteria↗

PubMed2005

Aflatoxin contamination of commercial maize products during an outbreak of acute aflatoxicosis in eastern and central Kenya.

In April 2004, one of the largest aflatoxicosis outbreaks occurred in rural Kenya, resulting in 317 cases and 125 deaths. Aflatoxin-contaminated homegrown maize was the source of the outbreak, but the extent of regional contamination and status of maize in commercial markets (market maize) were unknown. We conducted a cross-sectional survey to assess the extent of market maize contamination and evaluate the relationship between market maize aflatoxin and the aflatoxicosis outbreak. We surveyed 65 markets and 243 maize vendors and collected 350 maize products in the most affected districts. Fifty-five percent of maize products had aflatoxin levels greater than the Kenyan regulatory limit of 20 ppb, 35% had levels > 100 ppb, and 7% had levels > 1,000 ppb. Makueni, the district with the most aflatoxicosis case-patients, had significantly higher market maize aflatoxin than did Thika, the study district with fewest case-patients (geometric mean aflatoxin = 52.91 ppb vs. 7.52 ppb, p = 0.0004). Maize obtained from local farms in the affected area was significantly more likely to have aflatoxin levels > 20 ppb compared with maize bought from other regions of Kenya or other countries (odds ratio = 2.71; 95% confidence interval, 1.12-6.59). Contaminated homegrown maize bought from local farms in the affected area entered the distribution system, resulting in widespread aflatoxin contamination of market maize. Contaminated market maize, purchased by farmers after their homegrown supplies are exhausted, may represent a source of continued exposure to aflatoxin. Efforts to successfully interrupt exposure to aflatoxin during an outbreak must consider the potential role of the market system in sustaining exposure.

Aflatoxins↗

PubMed2003

Microbial contamination of disinfectants and antiseptics in four major hospitals in Trinidad.

OBJECTIVE: To assess the microbial contamination of disinfectants and antiseptics in major hospitals on the Caribbean island of Trinidad. METHODS: For this cross-sectional study, disinfectants and antiseptics were sampled from the pharmacy departments, the pediatric/neonatal wards, and the surgical wards of four hospitals. The samples were cultured for aerobic bacteria on nutrient agar using the surface plating method. The antibiotic sensitivity of bacterial isolates was determined by the disk diffusion method, using 14 antimicrobial agents. We studied a total of 180 disinfectant/antiseptic samples: 60 of chlorhexidine gluconate (Hibitane), 60 of chlorhexidine gluconate and cetrimonium bromide (Savlon), and 60 of methylated spirit. RESULTS: Of the 180 samples studied, 11 of them (6.1%) were contaminated by aerobic bacteria. All bacteria isolated were Pseudomonas spp. Of the 11 contaminated samples, 6 of them (54.5%) occurred at the pharmacy level while 5 (45.5%) were from diluted pre-use or in-use samples in the pediatric/neonatal wards or the surgical wards. Chlorhexidine gluconate and cetrimonium bromide accounted for 9 of the 11 contaminated disinfectants/antiseptics (81.8%), and chlorhexidine gluconate accounted for the remaining 2 (18.2%). Only two of the four hospitals had contaminated disinfectant/antiseptic samples. All 24 isolates of Pseudomonas spp. tested were resistant to one or more of the 14 antimicrobial agents tested, with the prevalence of resistance to ciprofloxacin, norfloxacin, tobramycin, and gentamicin being 58.3%, 50.0%, 45.8%, and 41.7%, respectively. CONCLUSIONS: Our results show that contaminated disinfectants/antiseptics pose a health risk to patients, particularly in the pediatric and surgical wards. The high prevalence of resistance to antimicrobial agents exhibited by the Pseudomonas spp. that were isolated is of special therapeutic concern.

Anti-Infective Agents, Local↗

PubMed1997

Contaminants of non-biological origin in foods from animals.

The authors provide an overview of non-biological contaminants in foods from animals. These contaminants comprise chemical and physical hazards which may be introduced during animal production, slaughter and processing or packaging. Emphasis in this paper is placed on those residues which are of most interest to Veterinary Services and for which Veterinary Services have responsibility, namely: residues of veterinary drugs, industrial chemicals, heavy metals and pesticides which may be introduced during animal production. The most contentious residues which occur in meat, milk and eggs are antibacterial drugs, hormonal growth promoters and certain pesticides, heavy metals and industrial chemicals. While rare incidents of human disease have been attributed to hazardous levels of these contaminants in milk and meat, residues of chemical contaminants in foods of animal origin are, in general, rarely detected at more than trace levels and consequently are not of major public health concern. Nevertheless, non-biological contaminants continue to be very important with respect to international trade and consumer confidence, and efforts to reduce the incidence of occurrence in foods is warranted. Furthermore, continued monitoring and periodic reassessment of risks posed by these contaminants is needed to detect or anticipate new problems so that appropriate action can be taken in the interests of public safety.

Animals↗

PubMed2004

[Foods with complaints of fungal contamination and physical problems caused by their ingestion].

A survey concerning foods for which complaints of fungal contamination had been made was carried out by distributing and retrieving a questionnaire. The subject of the survey was foods that were examined for fungi by institutes and laboratories belonging to regulatory agencies following consumers' complaints or upon request from food companies to solve problems. We analyzed 1,096 cases recovered from 40 organizations located in 30 prefectures. Most foods with fungal contamination were "cake and snacks", "beverages" and "bakery products", and processed and cooked foods and beverages accounted for more than 90% of the complaints. The numbers of cases were greater in the summer and less in the winter. The major fungal genus detected in the suspect foods were Penicillium, Aspergillus and Cladosporium. Aspergillus niger was the dominant species contaminating bakery products. Complainers reported physical symptoms including diarrhea, stomach ache, nausea and vomiting in 18% of the cases in which they had eaten or drunk fungus-contaminated foods or beverages. There was no clear difference in the fungi detected between foods and beverages that caused symptoms and those that did not. The proportion of beverages was greater in the foods that induced symptoms than in the whole of the foods for which complaints were made. This was presumed to be because consumers drank fungus-contaminated beverages more often than they ate fungus-contaminated foods.

Aspergillus↗

PubMed2006

[Comparison of glass particle contamination according to method of ampule cutting and needle aspiration].

PURPOSE: Glass particle contamination of the contents of single-dose glass ampules can occur upon opening. Different aspiration techniques, different sizes of needles, different sizes of ampules, and different cutting methods were studied to determine if they had any effect on glass particle contamination. METHOD: Different aspiration techniques(with filter, without filter), different sizes of needles(18G, 25G), different sizes of ampules(2 ml, 20 ml), and different cutting methods (with cotton, without cotton) were evaluated. METHOD: Twenty ampules were randomly assigned in each group. Three slides containing glass particles for each ampule were made and counted under a microscope by 3 study blind persons. RESULT: The number of glass particle contamination is much less when using a filter rather than without a filter. The number of glass particle contamination is much less when using a 25G needle rather than on 18G needle. The number of glass particle contamination is much less when using 2 ml ampules rather than 20 ml ampules. The number of glass particle contamination is much less when using cotton rather than without cotton. CONCLUSION: It was shown that using a filter, a small size needle, smaller sized ampules and using cotton when cutting the ampule will decrease the risk of parenteral injection of glass particles.

Drug Contamination↗

PubMed2000

Recalls of foods and cosmetics due to microbial contamination reported to the U.S. Food and Drug Administration.

In the U.S., food product recalls serve as an important intervention in stemming the consumption of food products contaminated with infectious disease agents. We summarize the number and nature of foods and cosmetics recalled as a result of microbial contamination reported to the U.S. Food and Drug Administration (FDA) for the period 1 October 1993 through 30 September 1998. During this period, microbial contamination of food and cosmetic products was the leading cause for recalls, accounting for a total of 1,370 recalls (36% of all products recalled). Listeria monocytogenes accounted for the greatest number of food products recalled because of microbial contamination, whereas Pseudomonas aeruginosa was the most common microbe associated with recalls of cosmetic products. Dairy products, followed by seafood and pastry items, were the types of products most often associated with recalls due to microbial contamination. The FDA was the entity most often responsible for detecting microbial contamination of foods and cosmetics (33% of all such recalls), followed by state regulatory agencies (24%), and manufacturers/retailers (21%). Nineteen percent of recalls were associated with at least one reported case of illness. Salmonella was the pathogen most often implicated in reports of illness associated with these recalled products.

Animals↗

PubMed2002

Association of Escherichia coli O157:H7 with preharvest leaf lettuce upon exposure to contaminated irrigation water.

Recent foodborne outbreaks have linked infection by enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 to the consumption of contaminated lettuce. Contamination via food handler error and on-the-farm contamination are thought to be responsible for several outbreaks. Though recent studies have examined the application of EHEC to store-bought lettuce, little is known about the attachment of EHEC to growing plants. We investigated the association of lettuce seedlings with EHEC O157:H7 strains implicated in lettuce or fruit outbreaks using hydroponic and soil model systems. EHEC strains that express the green fluorescent protein were observed by stereomicroscopy and confocal laser scanning microscopy to determine adherence patterns on growing lettuce seedlings. Bacteria adhered preferentially to plant roots in both model systems and to seed coats in the hydroponic system. Two of five nonpathogenic E. coli strains showed decreased adherence to seedling roots in the hydroponic system. EHEC was associated with plants in as few as 3 days in soil, and contamination levels were dose-dependent. EHEC levels associated with young plants inoculated with a low dose suggested that the bacteria had multiplied. These data suggest that preharvest crop contamination via contaminated irrigation water can occur through plant roots.

Bacterial Adhesion↗