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PubMed2002

Monitoring beef carcass surface microbial contamination with a luminescence-based bacterial phosphatase assay.

A commercially available microbial phosphatase test kit (Fast Contamination Indicator; FCI) was evaluated as a rapid method for estimating microbial contamination levels on beef carcass tissues. A set of actual beef carcass surface sample swabs (n = 70) was tested using the assay as a means to rapidly (10 min) monitor carcass swab sample microbial contamination. A regression equation was developed in experiment 1 and tested on an independent population. There was agreement between this assay and the conventional plating method for total aerobic mesophilic bacteria (r = 0.93). The predicted total mesophilic aerobic bacteria count generated from the fitted regression line (predicted log10 CFU/cm2 = 0.7505 x log10 FCI microbial phosphatase test values + 0.6726) showed a high correlation with actual aerobic mesophilic total counts (r = 0.88). The FCI test offers a simple and rapid method to estimate microbial contamination levels on beef carcasses.

Animals↗

PubMed1999

PCR-based identification of postmortem microbial contaminants--a preliminary study.

Investigation of postmortem blood can reveal the presence of significant ethanol levels. However, in some instances it cannot easily be determined if the source of ethanol is from ingestion or from postmortem endogenous fermentation by contaminating microbes. Described here is a robust polymerase chain reaction (PCR)-based method for detecting the presence of common ethanol producing microbial contaminants in human blood. A set of DNA primers were designed for use in PCR to amplify and detect the genomic DNA from humans and three test microorganisms Escherichia coli, Proteus vulgaris, and Candida albicans. A rapid and reproducible protocol was developed for isolating genomic DNA from mixed human blood-microorganism samples that yields a suitable template for PCR. The organism-specific primer pairs can detect the presence of the target microorganisms in human blood at concentrations as low as 10 colony forming units/mL. The PCR products readily can be detected after agarose gel electrophoresis. This method provides an additional means of rapidly identifying microbial contaminants in postmortem blood samples.

Candida albicans↗

PubMed1997

The potential for catheter microbial contamination from a needleless connector.

Needleless connectors have been widely introduced into clinical practice to allow the connection of syringes and luers to peripheral and central vascular catheters. The potential for microbial contamination of catheters via these devices is currently unclear. A recently introduced connector, the 'Connecta Clave', was assessed by various in-vitro methods. The 'Connecta Clave' is specifically devised to separate external components from the fluid pathway. The compression seals of 50 devices were contaminated with 1 x 10(4) cfu Staphylococcus epidermidis, disinfected with isopropanol, and fluid passed through. Only one device allowed organisms to pass through, despite this challenge, representing a contamination rate of 2%. In comparison, when 50 connectors were challenged with 20 cfu of S. epidermidis, no organisms passed through the device during use. In the clinical situation, after manipulation, < 16 cfu of skin organisms were found associated with the compression seal of the devices. It is, therefore, likely that the contamination rates in clinical practice will be extremely low. Three methods of disinfecting the compression seals and associated rims were also evaluated. A combination of alcohol chlorhexidine spray, followed by a 70% isopropanol swab, resulted in the most efficacious disinfection. The isopropanol swabs produced an adequate disinfection rate. The overall results suggest that by use of specially designed connectors, not only are needlestick injuries reduced, but the likelihood of microbial contamination of catheters via the internal route may also be diminished.

Catheters, Indwelling↗

PubMed1980

Control of microbial contamination in the use of laboratory rodents.

Historically, laboratory rodents have been used in preference to other animal species for biomedical research. Study disruptions and invalidations often have occurred due to microbial contaminants inherent to laboratory rodents. Today, many commercial suppliers and research institutions are controlling a variety of infectious diseases among laboratory rodents by careful design of animal facilities, by adaptation of managerial techniques employing precise operational policies coupled with careful supervision and attention to detail and the use of various diagnostic programs. The continued evolution of epidemiological practices, environment control systems, sophistication of barrier-sustained operations, preventative medicine and sanitation techniques, complemented by an improvement in veterinary diagnostic programs for disease surveillance further minimize microbial contamination of laboratory rodents. Such measures contribute to the fulfillment of various legislative requirements concerned with the quality of animals for biomedical research.

Animal Feed↗

PubMed2000

Microbial contamination of carcasses and equipment from an Iberian pig slaughterhouse.

The microbial contamination of carcasses and equipment has been studied in an industrial slaughterhouse of Iberian pigs. Samples of the surface of carcasses were taken at different stages of the process and aerobic plate count at 37 degrees C (APC), Enterobacteriaceae-count (E-count) and Escherichia coli-count (EC-count) were determined. It was demonstrated that in scalding and singeing the APC decreased (P < 0.01), while in the dehairing it increased (P < 0.01). The E-count and EC-count decreased in the scalding but increased in the evisceration (P < 0.001). The implementation of good manufacturing practices (GMP) in the stages of closure of the anus and evisceration significantly decreased the EC-count. It changed from 61.1% in carcasses without GMP that had counts higher than 1 log CFU/cm2 to only 7.4% in GMP carcasses. A final wash of the carcasses with potable water at high pressure (the only decontaminating treatment permitted in the European Union) was tested and failed to decrease the counts. It was also demonstrated that cleaning and disinfection of the dehairing and scraping machines is not effective.

Abattoirs↗

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↗

PubMed2001

[Analysis for microbial contamination in production of Japanese-style confectionery "Monaka"].

Food hygiene in Japanese-style confectionery factories is hard to practice because the businesses are small. In a supporting system of voluntary-based hygienic management in this field, we microbiologically investigated the production processes of "Monaka" in a workshop in Tokyo. We microbiologically assessed the processing environments as well as the products in the workshop, then proposed some improvements in the production of the confectionery. After the improvements, microbial contamination of the processing environments was reduced and no microbial contamination was found in the sugared bean, or "An" produced, though the product "Monaka" was still contaminated, especially by molds. It was clarified that the molds came from contaminated baked wheat shells, or "Kawa" and further that the wheat shells were contaminated by molds during storage.

Food Handling↗

PubMed2002

Determination of microbial contamination of plastic cups for dairy products and utilization of electron beam treatment for sterilization.

Packaging materials are often considered a critical control point in HACCP systems of food companies. Methods for the determination of the microbial contamination rate of plastic cups, especially for dairy products, must reliably detect single moulds, yeasts or coliforms. In this study, a comparison of a specially adapted coating method, impedance method, direct inoculation and membrane filter technique was carried out to determine contamination with yeasts, moulds, coliforms and total bacterial counts using the appropriate agar in each case. The coating method is recommended for determining yeasts, moulds and coliforms as it allows the localization of the microorganisms as well as the determination of single microorganisms. For total bacterial count, a direct inoculation technique is proposed. The employing of simple measures in the production and during transport of packaging materials, such as dust-prevention or tight sealing in polyethylene bags, heavily reduces microbial contamination rates of packaging material. To reduce contamination rates further, electron beam irradiation was applied: plastic cups sealed in polyethylene bags were treated with 4-5 kGy, a dose that already leads to sterile polystyrene and polypropylene cups without influencing mechanical characteristics of the packaging material.

Alternaria↗

PubMed1990

Effects of mastication and microbial contamination on ruminal in situ forage disappearance.

In an experiment to determine the effects of mastication and microbial contamination on in situ forage disappearance, samples of masticated (M) or nonmasticated alfalfa hay (AH), orchardgrass hay (OGH) and bermudagrass hay (BGH) were incubated in the rumen of two steers for 6, 12, 24, 48 and 96 h. Using diaminopimelic acid as a marker, microbial DM and CP contamination ranged from 10.3 to 22.3% and 46.3 to 95.3% of residual DM and CP, respectively. Percentage contamination was influenced by both time of incubation and forage treatment (P less than .001). Corrected DM and CP disappearances (DMD and CPD) were higher than apparent disappearances (P less than .001). Maximal NDF and ADF disappearances (NDFD and ADFD) obtained at 96 h were 58.2, 52.4; 62.7, 62.3 and 56.7, 52.6% for AH, OGH and BGH, respectively. Lag times (h) for corrected DMD and CPD were shorter (at least P less than .05) than for apparent disappearances, except for corrected CPD of AH. There were no differences (P greater than .10) in lag time of NDFD or ADFD among forages. Rates of disappearance (%/h) of corrected DMD and CPD were faster (at least P less than .01) than for apparent disappearances. The total quantity of microbial CP (mg CP/g DM) associated with residues varied with time depending on forage type (P less than .001). There was a significant relationship between the quantity of microbial CP contamination and the extent of disappearance. Masticated forages followed trends similar to those of nonmasticated forages, but the effect of mastication was not consistent. Results support the need for microbial correction of in situ forage residues.

Animals↗

PubMed2001

The effects of toothpastes on the residual microbial contamination of toothbrushes.

BACKGROUND: Contaminated toothbrushes have been shown to harbor and transmit viruses and bacteria. The authors conducted a study to evaluate the effect of a triclosan-containing toothpaste on the residual anaerobic microbial contamination of toothbrushes. METHODS: Twenty patients who had Type III or Type IV periodontitis participated in this study. One side of each of their mouths served as a control (no toothpaste). The teeth on the other side were brushed with a regular toothpaste or a triclosan-containing toothpaste. After the toothbrushes were allowed to dry in air for four hours, the authors placed the toothbrush heads in solution, dislodged the microbes from the brushes by vortexing and plated them in culture dishes. The authors anerobically incubated the culture dishes and determined the presence or absence of Prevotella species or Ps; Porphyromonas gingivalis, or Pg; and Actinobacillus actinomycetemcomitans, or Aa. RESULTS: The authors detected Aa and Pg on the control toothbrushes more frequently than they did Ps. This variation in isolation frequency was statistically significant by chi 2 analysis (P < .001). The authors compared the isolation frequency of the three test organisms between the control and regular-toothpaste groups, between the control and triclosan-containing--toothpaste groups, and between the triclosan-containing--toothpaste and regular-toothpaste groups. They found no significant intergroup differences in the isolation frequencies after using chi 2 analysis. CONCLUSIONS: Toothpaste use reduced the residual microbial contamination for two of three test organisms, but the lower isolation frequencies were not statistically significant. Further study in this area is indicated. CLINICAL IMPLICATIONS: Dental professionals should advise patients who have systemic, localized or oral inflammatory diseases to disinfect or frequently replace their toothbrushes.

Aggregatibacter actinomycetemcomitans↗

PubMed2005

Microbial contamination of dental unit water systems.

INTRODUCTION: Dental unit water systems (DUWS) may serve as a reservoir for biofilms that contribute to high numbers of bacteria in the water used during dental treatment. These microbes are predominantly harmless but potentially pathogenic organisms can also be present in the biofilm. This may pose a potential health risk for patients and dental personnel. AIM: to determine the microbial levels of DUWS in dental practices. MATERIALS AND METHOD: A cross-sectional study of water and tubing samples from 30 general dental practices (15 health board and 15 private surgeries) was undertaken as part of a pan-European investigation of the microbial qualitative and quantitative aspects of DUWS. RESULTS: Microbial loads ranged from 100 to 104 cfu ml-1 and exceeded the European guidelines for drinking water in many cases. The available evidence suggested the presence of isolates most likely belonging to families of aquatic and soil bacteria. It was not possible to draw distinct conclusions correlating microbial loads with dental unit parameters, including age of the unit, water source and chemistry and presence or absence of anti-retraction devices. Opportunistic or true pathogens were not detected. Yeasts were observed in samples from three units although further analysis confirmed that these were not Candida albicans. A decontamination strategy applied to one of the units eliminated the yeasts completely. CONCLUSIONS: Dental practitioners must be knowledgeable regarding microbial contamination and biofilm formation in dental unit waterlines. There is a need for development of European evidence-based guidelines and reliable control regimes for microbial contamination of DUWS.

Biofilms↗

PubMed1990

Microbial contamination of contact lens storage cases and solutions.

We compared microbial contamination of contact lens storage cases of asymptomatic contact lens wearers (Group 1; No. = 118; sampled once) and of contact lens wearers with manufacturer's lens-care instructions reinforced (Group 2; No. = 62; sampled three, six, 12, and 20 weeks after initial advisement). A significantly higher incidence of contamination of contact lens storage cases and solutions was observed among samples from Group 1 (132 of 247 samples) as compared to samples from Group 2 (30 of 500 samples; P = .000). Contact lens storage cases of individuals in Group 2 who used hydrogen peroxide systems (four of 78) showed a significantly lower incidence of contamination as compared to individuals who used other chemical disinfection (11 of 62 soft lens users; 10 of 59 rigid gas-permeable lens users; P = .041). Biofilms, adhered microorganisms embedded in a glycocalyx, in contact lens storage cases were not always inactivated by the addition of fresh solutions. Cleaning and periodic replacement of contact lens storage cases is recommended.

Bacteria↗

PubMed1968

Comparison of microbial contamination levels among hospital operating rooms and industrial clean rooms.

Microbial contamination in industrial clean rooms was compared quantitatively and qualitatively with that of hospital operating rooms. The number of aerobic mesophilic microorganisms which accumulated on stainless-steel strips exposed for periods up to 21 weeks to the intramural air of four operating rooms was at least 1 log higher than the accumulation on strips exposed in four clean rooms, and was essentially the same as that found in two factory areas. Volumetric air samplings showed that there were significantly higher numbers of airborne viable particles per cubic foot of air in operating rooms than in industrial clean rooms. In contrast to clean rooms, where most of the airborne contaminants were those associated with human hair, skin, and respiratory tract, the hospital operating rooms showed a very high level of microorganisms associated with dust and soil.

Air Microbiology↗

PubMed2000

Microbial contamination of enteral feeding formulas and diarrhea.

Twenty-five medical and surgical patients receiving liquid ready-to-use sterile enteral formulas were evaluated prospectively to investigate the relation of diarrhea to serum albumin level, total lymphocyte count, delayed hypersensitivity to purified protein derivative, antibiotic therapy, administration rate and site of enteral formula, and microbial contamination of enteral feeds. Formulas were administered to 6 patients with hang times of up to 6 h by pump-assisted continuous drip and to 19 patients with hang times of up to 3 h as a bolus feeding. Samples of formulas for microbial culture were obtained aseptically before and after feeding on the first and eighth day of the study period. The incidence of microbial contamination of the formula before and after feeding was 1 of 49 samples (2.0%) and 10 of 48 samples (20.8%), respectively. There were 2 patients with diarrhea, which occurred on the second day. Formula samples from 2 patients (100%) with diarrhea and 2 samples from 23 patients (8.7%) without diarrhea were contaminated with 10(4) cfu/mL or more, respectively. A significant difference (P = 0.04) was detected between the two groups. The other factors studied showed no significant association with the incidence of diarrhea. In conclusion, contaminated formula appears to play a significant role in the etiology of diarrhea in patients receiving enteral feeding.

Acinetobacter↗

PubMed1985

Microbial contamination potential of sterile disposable plastic syringes.

The contamination potential of sterile disposable plastic syringes was evaluated after subjecting the syringes to both simulated in-use conditions and an intentional microbial challenge. Lots of 20 Luer-lock syringes in 10 or 12-cu cm and 20- or 30-cu cm sizes from three manufacturers were tested. Sampling was conducted using 30-ml vials of sterile aerobic culture media containing 14C-labeled substrates. Microbial contamination was confirmed by both visual observation of the turbidity caused by colonization and instrumental detection of 14CO2 caused by the microbial metabolism of 14C-substrates. No contamination of 120 samples was found after the ribbed plunger shaft was grasped by a bare, unprepared dry hand during five cycles of filling and injecting the medium into the vials without removing the needles from the stoppers. When this sampling technique was applied to the syringes inoculated on the upper piston surface with Bacillus subtilis suspension, a 100% contamination rate was observed in 120 samples each under both positive and negative in-vial pressure. Grasping the ribbed plunger shaft of disposable plastic syringes with a dry bare hand did not compromise the sterility of the syringe contents in this study; however, this practice should be avoided when possible. Personnel should absolutely avoid introducing fluid-borne microbial contaminants into the distal barrel end of these syringes because the contents are readily labile to contamination under these conditions.

Bacillus subtilis↗

PubMed1992

Microbial contamination of ambient air by ultrasonic humidifier and preventive measures.

The microbially contaminated ultrasonic humidifier (UH) causes humidifier fever. The number of airborne viable bacteria was determined when the UH was operating, and other methods to humidify the air of hospital wards were also examined. A UH contaminated with 10(5) bacteria ml(-1), a level common in hospitals, increased the bacterial count in the air from 860 m(-3) to 88,000 m(-3) at a distance of 3 m from the humidifier. Thus UH in hospitals may contaminate the air and be a potential hazard to patients. Contamination was slight when a washable and disinfectable ultrasonic nebulizer was used with disinfection at 24 h intervals. In tracheostomy patients requiring a high degree of air humidification, ultrasonic nebulizers which are readily washed and disinfected are recommended.

Aerosols↗

PubMed1993

Microbial contamination of enteral feeding solution and its prevention.

In an investigation of microbial contamination of enteral feeding solutions, all 22 residual solutions obtained immediately after administration were contaminated at concentrations of 10(3) to 10(6) viable counts/ml. Major contaminants were glucose-nonfermenting gram-negative bacilli such as Pseudomonas aeruginosa and Acinetobacter calcoaceticus var anitratus. Contamination seemed to have been caused by frequent reuse of bag-type containers and the infusion tubes connected to the bags, neither of which can be washed or dried. Decontamination methods were evaluated by using polypropylene containers that can be washed and disinfected for administration. Few Serratia marcescens on the inside wall of the container were removed by rinsing with tap water, alone or in combination with detergent scrub. Tap water and detergent plus air-drying at 56 degrees C for 1 hour reduced Serratia marcescens only somewhat. Tap water and detergent plus immersion in 0.01% sodium hypochlorite for 1 hour or in water at 70 degrees C for 3 minutes eliminated all 10(11) cells of Serratia marcescens.

Bacteria↗

PubMed1996

Investigations into the microbial contamination of toothbrushes.

Used brushes (28 in toto) were assessed for microbial contamination. The micro-organisms removed from the toothbrush heads were plated onto a range of selective media. The total number of micro-organisms isolated per brush varied from 0 to 10(8) CFU. Staphylococci, coliforms, pseudomonads and yeasts were isolated from 64, 57, 28 and 39% of brushes, respectively. Identification tests on representative colonies indicated that media for streptococci, staphylococci, yeasts and pseudomonads were selecting for appropriate growth with > 90% efficiency. Of those tested on MacConkey agar eight from eleven colonies were oxidase negative, Gram-negative rods; the remainder were oxidase positive. No black pigmented obligate anaerobes were isolated. None of the seventeen colony types on Helicobacter selective agar proved to belong to that genus. Scanning electron microscopy of bristles revealed toothpaste debris, but micro-organisms were not evident.

Bacteria↗