High Levels Of Microbial Contamination Research Articles

Effect of cleaning and disinfection on naturally contaminated clinical contact surfaces

Introduction. Data regarding methicillin-resistant Staphylococcus aureus, Legionella pneumophila, Hepatitis B virus suggest that the environment plays an important role in infection transmission in dental healthcare settings. The Centres for Disease Control and Prevention suggest covering clinical contact surfaces with disposal barriers or disinfecting them between patients. Both methods have drawbacks; preliminary data suggest that cleaning could be an alternative. Aim. To investigate microbial contamination on dental chairs after dental therapy with turbine and decontamination power of disinfection and cleaning. Material and methods. We assessed microbial contamination of a dental chair, used by paediatric patients receiving conservative/ endodontic therapy and located in an annex isolated from the rest of the dental office. Contact plates containing Nutrient Agar were used to assess microbial load, immediately before and after treatment, and following one of two decontamination protocols. Protocol-1 comprised cleaning (sodium lauryl sulphate- based soap) followed by disinfection (hypochlorite solution); and protocol-2 was soap-based cleaning only. Contamination levels were classified as no growth; scanty (<2.5 CFU/ cm2); light (2.5-12 CFU/cm2); moderate (12-40 CFU/cm2); or heavy growth (40-100 CFU/cm2). Results. Contamination ranged between moderate and heavy growth for 93.3% samples after dental therapy before decontamination. Scanty growth was obtained from 93.3% samples and 96.7% samples after protocol 1 and protocol-2, respectively. Initial level of contamination had no significant effect on the final level and the decontamination power of the two protocols was not significantly different either. Conclusion. Dental therapy produced high levels of microbial contamination which justified the use of adequate disinfection and/or cleaning. Cleaning alone was sufficient to decontaminate the surface of the dental chair, while disinfection offered no additional effect.

Microbiological Quality Assessment of Vitamin B Syrups and Antibiotic Susceptibility Profile of the Isolated Escherichia coli

The microbiological quality of 15 different vitamin B syrup samples of 7 pharmaceutical companies was assessed. The total aerobic microbial count (TAMC) varied between 1.0×10 1 CFU/ml and 6.0×10 3 CFU/ml. The total yeast and mold count (TYMC) ranged from 1.0×10 1 CFU/ml to 5.3×10 2 CFU/ml. In general, all the samples tested were contaminated with microorganisms. Our findings revealed that 10 (66.67%) out of the 15 samples exceeded the microbiological acceptance limit of USP. Moreover, presence of Escherichia coli was detected in 2 samples. The E. coli isolates were subjected to antibiotic susceptibility test against 7 antibiotics. All the E. coli isolates showed resistance against ampicillin and 2 (33.33%) of the isolates showed resistance against cefaclor. None of the isolates demonstrated resistance against ciprofloxacin, kanamycin, meropenem, streptomycin and tetracycline. Presence of antibiotic resistant bacteria in pharmaceutical products is very alarming for the consumer. The presence of high level of microbial contamination highlighted the need to reevaluate the production process of the pharmaceutical companies involved in production of non-sterile products and take necessary steps to prevent microbial contamination.

Microbial Contamination in Vegetables at the Farm Gate Due to Irrigation with Wastewater in the Tamale Metropolis of Northern Ghana

The rational for this study was to assess the microbial quality of fresh vegetables at the farm gate of the Water Works road vegetable farm at Gumbihini in the Tamale Metropolis. A total of thirty-six (36) vegetables comprising lettuce, amarantus and cabbages and eight (8) wastewater samples were collected at random and analysed for a period of four months, to assess the microbial contamination level. Samples were analysed for total coliforms, faecal coliforms, E. coli and helminthes eggs. All vegetables sampled during the study period recorded high levels of total and faecal coliform bacteria. Mean faecal coliforms for the various vegetables were as follows; lettuce 3.7 ± 0.5 CFU.g-1, amarantus 3.5 ± 0.6 CFU.g-1 and cabbage 3.1 ± 0.6 log CFU.g-1 fresh weight. FC levels were above the International Commission on Microbiological Specifications for Foods (ICMSF) recommended level of 3 log CFU.g-1 fresh weight. E. coli were recorded in lettuce (3.3 ± 0.6 log CFU.g-1 fresh weight) and amarantus (0.6 ± 0.1 log CFU.g-1 fresh weight) but not in cabbages. Lettuce generally recorded high levels of microbial contamination because of the large surface area occupied by its leaves. Two helminth eggs (Strongiloides stercoralis) were identified in lettuce while four (Ascaris lumbricoides) were identified in wastewater. Microbial loads recorded in wastewater were generally higher than that of vegetables. Since most of these vegetables are eaten fresh or slightly cooked, there is course for concern as public health will be adversely affected. Education of farmers and consumers on food safety has to be intensified to avert a possible outbreak.

진해만 서부 용남·광도해역의 세균학적 수질에 미치는 육상 오염원의 영향

To evaluate the bacteriological water quality in Yongnam-Gwangdo, located in western Jinhae Bay, seawater samples were analyzed using sanitary indicator bacteria at 57 sampling stations. According to survey results from January 2007 to December 2009, the range of the geometric mean and the estimated 90th percentile for coliforms and fecal coliforms in the samples were <1.8-16.5 and 1.8-246.8 MPN/100 mL and <1.8-7.1 and 1.8-74.8 MPN/100 mL, respectively. The samples, including those taken from stations located in Wonmunman, Gwangdo, and Dangdong, showed high levels of microbial contamination caused by the climate and weather patterns in the marine environment. The bacteriological water quality in the area met Korean criteria for a designated shellfish growing area for export and National Shellfish Sanitation Program criteria for an approved shellfish growing area, except at station #49. A total of 24 direct pollution sources were discharged into the shellfish growing area. The radius of impact was calculated for each pollution source to assess the effect on the shellfish growing area. The calculated radius of impact for most of the pollution sources was below 300 m. However, the radius of impact for the combined pollution sources in Kyeonnaeryang was 93-1973 m. There were significant differences between the calculated closed sea area and actual monitoring results. The closed sea area values calculated from the fecal coliform load in drainage water tended to be higher than the actual monitoring results. Tidal currents and environmental factors such as salinity, water temperature, sunlight, and microbiological factors affect the survival of fecal indicator bacteria in seawater.

Update on infectious risks associated with dental unit waterlines

Modern dental chair units consist of a network of interconnected narrow-bore plastic tubes called dental unit waterlines (DUWLs). The water delivered by these DUWLs acts as both a coolant for a range of instruments and an irrigant during dental treatments. The quality of water is of considerable importance because both patients and dental team are regularly exposed to water and aerosols generated by dental equipment. Studies have demonstrated that DUWLs provide a favourable environment for microbial proliferation and biofilm formation, and that water is consequently often contaminated with high densities of various microorganisms (bacteria, fungi, protozoa, viruses). The presence of high levels of microbial contamination may be a health problem for dentists and patients, especially those who are immunocompromised. The current status of knowledge on microbial contamination of DUWLs is presented, with an emphasis on the infectious risk associated with DUWLs and on the various approaches for disinfecting and protecting DUWLs.

Microbial safety of raw mixed-vegetable salad sold as an accompaniment to street vended cooked rice in Accra, Ghana

A survey of 90 randomly selected subjects indicated raw mixed-vegetable salad as a popular accompaniment to cooked rice sold by street-food vendors in the Kokomlemle municipality of Accra, Ghana, but the salad was generally considered unwholesome and a potential cause of diarrhoea. A survey of 15 vendors of cooked rice indicated that the sources of raw vegetables, method of transportation from the sources to the kitchens, and methods of storing the raw vegetables before processing, as well as the methods of processing and sale, made the raw mixed-vegetable salad accompaniment a potential source of food poisoning from microbial contamination. Microbial analysis of samples of the salads obtained from five randomly selected vendors in the mornings and afternoons, over 15 days, indicated that bacterial counts for all samples exceeded the recommended World Health Organization (WHO) standard of Log10 3.0 cfu/g. Levels of Pseudomonas, Salmonella typhi, Shigella sp., and Streptococcus faecalis did not show any significant difference (P<0.05) among vendors and did not differ significantly (P<0.05) over the 15 days. Significantly, higher levels of microbial contamination (P<0.05) occurred in the afternoon, than in the morning samples. The results confirm that the raw mixed vegetable salads which are sold as accompaniment to street vended cooked rice in the Kokomlemle municipality contain S. faecalis from fecal contamination, Pseudomonas, Shigella sp., and S. typhi which could cause gastrointestinal infections and the highest risk was from the afternoon samples.

Microbial challenges of poultry meat production

Food safety and shelf-life are both important microbial concerns in relation to broiler meat production. Focus is mainly placed on the absence or control of potentially pathogenic microbes such as Salmonella spp. and Campylobacter spp. but, from the commercial point of view, other spoilage bacteria also play a role as potential threats. Regarding food safety, the primary target should be the production of pathogen-free live animals, thus allowing slaughter plants to keep the processing line free of those microorganisms. Consumers believe that quality of foods from organic production is superior to foods from conventional production. The aim of the present study was to evaluate and compare the bacterial quality of chicken meat from organic and conventional production on the basis of traditional meat quality criteria. Fresh free grazing broiler carcasses were purchased directly from rural households ( n = 80) and fresh retail chicken parts from conventional broiler carcasses from the local supermarkets in the region of Epirus (Poultry Producers Association. Arta) ( n = 200). The samples were microbiologically tested for the presence of bacteria such as: Salmonella spp., Listeria monocytogenes, Staphylococcus aureus, Enterobacteriaceae, Escherichia coli, Campylobacter spp., and C. perfringens. Total count of aerobic mesophilic bacteria was also determined. Bacteriological tests were performed by means of standard methods of isolation and identification of individual species of bacteria according to ISO requirements. API-tests (bioMerieux) and Vitek 2 Identification System (bioMerieux) were used for biochemical determination. High levels of microbial contamination and occurrence of pathogenic bacteria at then fresh free grazing broiler carcasses reflect the poor hygienic quality of the slaughter conditions in the rural households.

Interferência da microbiota autóctone do queijo coalho sobre Staphylococcus coagulase positiva

High levels of microbial contamination, commonly found in animal origin foods and food processing environments, are able to hinder the growth in these products. In some contexts where lactic acid bacteria (LAB) are the normal dominant microbiota, such as in fermented food, Staphylococcus coagulase positive (SCP) colonises, persists and produces food poisoning. With the aim of verifying the interference of autochthonous microbiota encountered in Curd cheese over the presence of Staphylococcus aureus, 64 samples from 16 dairy were submitted to microbiological analysis to determine the levels of Microorganisms aerobes mesophilics (MAM), LAB and SCP. The results showed that the indigenous microbiota of the samples did not lead to inadequate growth, development and isolation of SCP, since this pathogen was detected even in samples with high levels of counts of AM and BAL.

A novel multiplexed immunoassay using salivary antibodies to detect human exposure to waterborne pathogens in drinking and recreational water (65.19)

Abstract Water is our most important resource and the world’s supply is becoming alarmingly limited with rising concern about the high levels of microbial contamination. We are developing a novel strategy to assess human exposure to microbial contaminants in drinking and recreational water using a multiplexed, high-throughput immunoassay applying the Luminex xMAP platform. In this assay, antigens from waterborne pathogens are coupled to spectrally unique microspheres that are exposed to either pathogen-specific antibodies or human saliva. Our results indicate that multiplexed microsphere sets coated with antigens to Helicobacter pylori, Salmonella typhimurium, Escherichia coli O157:H7, Campylobacter jejuni, Toxoplasma gondii, Cryptosporidium parvum, and Giardia lamblia are able to capture both pathogen-specific antibodies and human salivary antibodies at the lowest-limit of detection of the assay. Additionally, we implemented a Design of Experiment (DoE) approach to evaluate the impact of antigen and antibody concentration on the detection level of H. pylori. From this work, we were able to generate a mathematical model describing the detection level as a function of critical process parameters to determine optimal conditions for protein coupling to Luminex beads. This immunoassay will allow for a sensitive, rapid, and cost-effective analysis of human exposure to waterborne pathogens with the potential to reduce the cost of epidemiological surveillance of waterborne infections.

Impact of Air-Drying Lens Cases in Various Locations and Positions

To determine the rate and type of microbial contamination when contact lens cases are air-dried in two different positions (face up and face down) and in four different locations (toilet, bathroom, office, and bedroom). Unused contact lens cases (n = 97) were rinsed with 2-ml sterile phosphate buffered saline and then placed on facial tissue paper in different locations: humid (toilet and bathroom) and non-humid (office and bedroom) and air-dried at room temperature. After 24 h, the contact lens cases were collected and sampled for microbial numbers and microbial types identified using standard techniques. The microbial profile and the rate of contamination between different locations and positions were compared. Irrespective of the air-drying location, contact lens cases positioned face up had a significantly higher contamination rate (34/48, 71%) compared with contact lens cases air-dried face down (6/49, 12%) (p < 0.001). For those contact lens cases air-dried face up, there was more contamination when placed in humid environments (toilet and bathroom) than in the non-humid environments (office and bedroom) (p = 0.01). However, the contact lens case contamination rate among various locations was similar when contact lens cases were air-dried face down. Total microorganisms recovered from contact lens cases ranged from 0 to 275 colony forming unit per well. The most frequently recovered microorganisms from the contaminated contact lens cases were coagulase-negative Staphylococci, fungi, and Bacillus spp. Thirty-three percent (13/40) of contact lens cases were contaminated with multiple species. Small numbers of microorganisms from the environment may contaminate contact lens cases while cases are air-dried face up. Cases air-dried in humid environments have higher levels of microbial contamination; this is particularly true when contact lens cases are positioned face up. On the basis of this limited study, we would recommend contact lens cases be air-dried face down.

Effects of Ionizing Radiation on Microbial Decontamination, Phenolic Contents, and Antioxidant Properties of Triphala

Triphala, a mixture of Emblica officinalis, Terminalia chebula, and Terminalia bellirica, containing ingredients from plant origin, is often prone to microbial contamination. A high level of microbial contamination was observed in Triphala samples obtained from different sources. On gamma radiation processing, a sharp decline in log CFU was observed with increasing radiation dose and a complete decontamination at 5 kGy. Average D10 value for total aerobic and fungal counts were observed to be 0.55 +/- 0.073 kGy and 0.94 +/- 0.043 kGy, respectively. Water extracts of irradiated samples showed linearly increasing concentration of gallic acid (3.3 to 4.5 times), total phenolic contents (2.16 to 2.87 times), and antioxidant properties with increasing radiation dose up to 25 kGy. The increase could be attributed to easy release of active ingredients from their radiation degraded complex forms. Aflatoxin B(1) and ochratoxin could not be detected in the samples. Gamma-radiation dose up to 5 kGy could be safely used to hygienize Triphala.

Assessment of microbiological quality of drinking water from household tanks in Bermuda

Bermuda residents collect rainwater from rooftops to fulfil their freshwater needs. The objective of this study was to assess the microbiological quality of drinking water in household tanks throughout Bermuda. The tanks surveyed were selected randomly from the electoral register. Governmental officers visited the selected household (n = 102) to collect water samples and administer a short questionnaire about the tank characteristics, the residents' habits in terms of water use, and general information on the water collecting system and its maintenance. At the same time, water samples were collected for analysis and total coliforms and Escherichia coli were determined by 2 methods (membrane filtration and culture on chromogenic media, Colilert kit). Results from the 2 methods were highly correlated and showed that approximately 90% of the samples analysed were contaminated with total coliforms in concentrations exceeding 10 CFU/100 mL, and approximately 66% of samples showed contamination with E. coli. Tank cleaning in the year prior to sampling seems to protect against water contamination. If rainwater collection from roofs is the most efficient mean for providing freshwater to Bermudians, it must not be considered a source of high quality drinking water because of the high levels of microbial contamination.

Microbial contamination of dental unit waterlines in Istanbul, Turkey

The water used in dental unit waterlines (DUWLs) acts as a coolant for the high-speed equipment and as an irrigant during dental treatments. There are kind of water tanks. DUWLs provide a favorable environment for microbial biofilm and multiplation primarily due to the high surface in the tubing and the character of fluid dynamics in narrow, smooth-walled waterlines. Biofilms can harbour opportunist pathogens such as Legionella sp., Pseudomonas sp. Several studies have shown that DUWLs have high levels of microbial contamination. Presence of high level of microbial contamination is an important problem for dentists and dental patients who are immunocompromised. We collected water samples from DUWLs of 20 private dental offices. We have determined that only 2 (3.4%) out of 59 dental unit water samples were found to meet the standard (<200 CFU.ml(-1)) for DUWLs water quality by American Dental Association (ADA). Of the 59 water samples examined, 14 (24%) were positive for Pseudomonas sp. and 18 (30.5%) were positive for fungi. The most common 14 bacterial strains and seven fungi were isolated. Of bacterial strains, 57.1% were identified: Majority of the bacterial species isolated from our samples was identified as Pseudomonas fluorescens, Pasteurella haemolytica, Photobacterium damsela, Ochrobacter anthropi, Moraxella sp., Aspergillus flavus, Penicillium expansum. Legionella sp. were not detected in all water samples.

Listeria spp. associated to different levels of autochthonous microbiota in meat, meat products and processing plants

High levels of microbial contamination, commonly found in animal origin foods and food processing environments, are able to hinder the growth of pathogens in these products and interfere in the results of laboratory analyses for detection of these pathogens. With the aim of verifying the possible interference of the autochthonous microbiota encountered in meat and meat products and processing plants over the presence of Listeria spp., 443 samples, collected from 11 meat retail establishments, were submitted to microbiological analysis to determine the levels of mesophilic aerobes, total coliforms and Escherichia coli and the presence of Listeria spp., according to the methodology proposed by the USDA. The results did not show evident interference of the autochthonous microbiota over Listeria spp., once the genus was detected even in the meat, meat products and environmental samples with high levels of contamination by mesophilic aerobes and coliforms.

Comparative Study of Microbiological Quality of Raw Poultry Meat at Various Seasons and for Different Slaughtering Processes in Casablanca (Morocco)

The aim of the present study was to evaluate the bacterial quality of chicken (n = 96) and turkey (n = 96) marketed in Casablanca, Morocco. Poultry samples (n = 192) were collected randomly from traditional shops and supermarkets during 2 sampling periods (hot and cold seasons). The samples were analyzed for the presence and counts of various bacteria. Results indicated that aerobic plate counts and fecal coliforms were particularly high in all the samples analyzed. Escherichia coli, coagulase-positive Staphylococcus, Clostridium perfringens, Salmonella, and Listeria monocytogenes were detected, respectively, in 48.4, 10.4, 7.2, 1.6, and 0.5% of the poultry meat samples. The chicken and turkey samples contained, respectively, 25 and 33.3% of bacteria above the maximum limits established by the Moroccan regulatory standards. The highest bacterial counts in poultry meat product samples were recorded with the traditional slaughtering process during the hot season (P < 0.05). These high levels of microbial contamination and occurrence of pathogenic bacteria reflect the poor hygienic quality of poultry meat under these conditions.

Microbiological evaluation of dental unit water systems in general dental practice in Europe.

A range of opportunistic pathogens have been associated with dental unit water systems (DUWS), particularly in the biofilms that can line the tubing. This study therefore aimed to assess the microbiology of DUWS and biofilms in general dental practices across seven European countries, including the United Kingdom (UK), Ireland (IRL), Greece (GR), Spain (ES), Germany (D), Denmark (DK) and the Netherlands (NL). Water supplied by 51% of 237 dental unit water lines exceeded current American Dental Association recommendations of < or = 200 colony-forming units (CFU) ml(-1). Microbiological loading of the source waters was between 0 (Denmark, the Netherlands and Spain) and 4.67 (IRL) log CFU ml(-1); water line samples from the DUWS ranged from 1.52 (ES) to 2.79 (GR) log CFU ml(-1); and biofilm counts ranged from 1.49 (GR) to 3.22 (DK) log CFU.cm(-2). Opportunistic pathogens such as legionellae (DK and ES), including Legionella pneumophila SG1 (DK and GR), and Mycobacterium spp. (DK, NL, GR, D and ES) were recovered occasionally. Presumptive oral streptococci (ES and NL), oral anaerobes (GR), Candida spp. (UK, NL and ES) and blood (GR and IRL) were detected at relatively low frequencies, but their presence indicated a failure of the 3-in-1 antiretraction valve, leading to back siphonage of oral fluids into the water and biofilm phase. These findings confirm that a substantial proportion of DUWS have high levels of microbial contamination, irrespective of country, type of equipment and source water. The study emphasizes the need for effective mechanisms to reduce the microbial burden within DUWS, and highlights the risk of occupational exposure and cross-infection in general dental practice.

Monitoring the microbial contamination of beef carcass tissue with a rapid chromogenic Limulus amoebocyte lysate endpoint assay.

A chromogenic Limulus amoebocyte lysate (LAL) endpoint assay was found to be an accurate and rapid means of gauging levels of beef carcass microbial contamination within 10 min. The assay demonstrated a high correlation with the total mesophilic bacterial and coliform surface populations from inoculated beef carcass surface tissues. This assay was tested on a set of actual beef carcass surface samples (n = 121) demonstrating the utility of the chromogenic LAL test as a means of monitoring carcass microbial contamination in a near real-time fashion. Classifying the chromogenic LAL results into four contamination groups was found to be a sound means of utilizing the resultant chromogenic LAL data for detecting carcasses with high levels of microbial contamination. For beef carcass testing, this assay can be used with no instrumentation other than the required 37 degrees C incubator and, as an option, a microplate reader.

Microbial flora of &lt;i&gt;Anchovis&lt;/i&gt; spp. used in poultry and livestock feed preparation in Ghana

Anchovis spp. is of great importance in non-industrial feed formulation in Ghana as the main protein ingredient. Many microbial diseases found in poultry/livestock in Ghana are suspected to be due to contaminants on the fish in feed. Results from this survey suggest high levels of microbial contamination on the Anchovis fish. Seventeen genera of bacteria were isolated from Anchovis spp. samples taken along the coastal towns and markets in Ghana. The genera of bacteria isolated included Coliforms, Staphylococcus, Salmonella, Streptococcus, Pasteurella, Escheriachia, Shigela, and Pseudomanas. These organisms are known to cause various diseases in man and animals, resulting in economic losses. Caution should, therefore, be taken in the use of Anchovis spp. in human food and animal feed, since it can be a source of bacterial infection. Ghana Jnl agric Sci. Vol.32(2) 1999: 185-188

High levels of microbial contamination of vegetables irrigated with wastewater by the drip method

The public health aspects of the use of wastewater in agriculture and the effects of the drip irrigation method on the contamination of vegetables were studied. The method used was to simulate enteric microorganisms' dissemination by contaminated irrigation water in the field. The vegetables were irrigated with an effluent inoculated with a high titer of traceable microorganisms: poliovirus vaccine and a drug-resistant Escherichia coli. The dissemination of the marker organisms in the field was followed, and the effects of certain manipulations of the drip irrigation method on the contamination of the crops by the effluent were examined. It was shown that drip irrigation under plastic sheet cover with the drip lines placed either on the soil surface or buried at a depth of 10 cm significantly reduced crop contamination from inoculated irrigation water even when massive doses of bacteria and viruses were used. The microbial contamination was found to persist in the irrigation pipes and in the soil for at least 8 and 18 days, respectively. The data indicate that the recovery of the marker organisms was affected by soil texture and environmental conditions.