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1.
The aim of this study was to determine the prevalence of Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA) in whole raw chickens in China. A total of 1152 whole chicken samples were collected from three types of retail markets (large supermarket, small supermarket, and farmers market) in six provinces and two national cities in China and screened for the presence of. S. aureus, then the S. aureus isolates were further examined for the presence of MRSA. The overall positive rate for S. aureus was 24.2%. S. aureus prevalence was highest in Shaanxi province (39.6%), followed by Fujian province (31.3%), then Sichuan and Guangdong provinces (26.4% in each province), Shanghai (23.6%), Beijing (19.4%), Henan province (13.9%), the lowest prevalence was found in Guangxi province (13.2%). S. aureus prevalence was significantly different among the six provinces and two national cities (P < 0.05). Among 1152 chicken samples, twenty samples (1.7%) were positive for MRSA. MRSA prevalence was highest in Shaanxi province and Sichuan province (3.5% for each), then Fujian province (2.8%), Guangdong province and Shanghai (2.1% for each); MRSA isolates were not detected from Beijing, Henan province and Guangxi province. The overall S. aureus prevalence in chickens collected from large supermarket, small supermarket, and farmers market were 26.3%, 25%, and 21.4%, respectively, but differences were not significant (P > 0.05). These findings indicate the need for identifying the factors contributing to the contamination at the farm, processing and retail level, and for the implementation of good manufacturing practice to better control the pathogen throughout poultry industry.  相似文献   

2.
We investigated the prevalence of Staphylococcus aureus and multidrug including methicillin-resistant S. aureus (MRSA) in poultry retail meat samples from the Maryland-Washington DC metro area. A total of 24 S. aureus isolates were recovered from 96 whole poultry carcass samples and the prevalence of S. aureus were 25.0%, 14.29%, and 33.3% in retail poultry meats collected from farmers markets, organic and conventional retail supermarkets, respectively. Both single and multi-drug resistance isolates were detected in 58.3% (7/12) isolates from conventional retail meat products but none from farmers markets or organic retail meat isolates. Conventional retail meat isolates were found to be resistant to both erythromycin (50.0%) and tetracycline (58.3%). We also detected an MRSA isolate harboring mecA gene in conventional retail meat which showed co-resistance towards erythromycin, tetracycline, and vancomycin.  相似文献   

3.
Biofilm formation by Staphylococcus aureus plays a critical role in the persistence of chronic infections because of the ability of the bacterium in biofilms to tolerate antibiotics and host defenses. S. aureus produces hemolysin, which has been implicated in the pathogenesis of sepsis and pneumonia. Hence, the inhibitions of biofilm formation and/or toxin production by S. aureus are viewed as alternative means of addressing infections. In the present study, the antibiofilm activities of Moringa oleifera extracts were examined. Of the various solvent extraction methods examined, the supercritical carbon dioxide extracts of the leaves and seeds of M. oleifera were found to efficiently inhibit biofilm formation by S. aureus. Analyses of the extracts by GC-MS revealed the presences of palmitoleic acid, oleic acid, linoleic acid, linolenic acid, cis-11-eicosenoic acid, and cis-11,14-eicosadienoic acid at concentrations of 0.01% significantly inhibited S. aureus biofilm formation. In addition, supercritical fluid extract of the leaves of M. oleifera and its major component cis-11-eicosenoic acid significantly decreased the hemolysis of human red blood cells by S. aureus. These findings suggest supercritical carbon dioxide fluid extract of M. oleifera and its unsaturated fatty acids are potentially useful for controlling biofilm formation by and the virulence of S. aureus.  相似文献   

4.
Contamination of ready-to-eat meat products by foodborne pathogens is a major concern in the food industry. Novel methods to control foodborne pathogens are made necessary by continuing outbreaks as well as the development of antibiotic-resistant pathogens. Hibiscus sabdariffa extracts could be useful as a natural source of antimicrobial rinse on ready-to-eat products to control pathogens. In this study, lyophilized Hibiscus flower extracts were examined for their antimicrobial activity as a rinse on all-beef hot dogs against Listeria monocytogenes and methicillin-resistant Staphylococcus aureus (MRSA). Beef hot dogs were dip inoculated in overnight cultures of 1:1 mixtures of L. monocytogenes strains Scott A and 101 or MRSA strains ATCC 33591 and ATCC 33593 and were placed at 4 °C overnight to allow for bacterial attachment. Hot dogs were rinsed with extracts (120, 240 mg/mL) or water (control) for 5, 15, 30, or 60 min and then plated immediately (0 h; no storage) or stored at 4 °C overnight and plated at 24 h. Serial dilutions were plated in duplicate on both TSA and selection media, Modified Oxford (Listeria) or Baird Parker (MRSA), and the entire experiment was replicated 3 times. Higher extract concentrations, longer rinse times, and longer storage times were the most effective at inhibiting and/or killing L. monocytogenes and MRSA on hot dogs. L. monocytogenes was reduced to ca. 1.5 log CFU/g while MRSA was reduced to undetectable levels following rinsing of hot dogs with extracts at 240 mg/mL for 60 min and stored for 24 h. Both L. monocytogenes and MRSA were reduced ca. 2 log CFU/g following rinsing of hot dogs with extracts at 120 mg/mL for 60 min and stored for 24 h. This research demonstrates the effectiveness of Hibiscus extracts against L. monocytogenes and MRSA as an antimicrobial rinse on ready-to-eat meat products.  相似文献   

5.
《Food Control》2006,17(5):389-392
In this study, a total of 180 samples of raw milk, pasteurised milk and ice cream were analysed for the presence of Staphylococcus aureus. There were 110 S. aureus isolated from these samples, which were investigated for DNase activity, slime production and antibiotic resistance. DNase agar that was used to investigate for DNase activity revealed DNase activity in 94.5% of 110 S. aureus. Slime production of S. aureus that was investigated by using Congo Red Agar method revealed slime production in 52.7% of S. aureus. Resistance of S. aureus to different antibiotics was determined by the Kirby–Bauer disc diffusion test. Resistance to penicillin G, methicillin and bacitracin was frequent for S. aureus strains. Few numbers of the strains were resistant to erythromycin. All strains were susceptible to vancomycin, sulbactam–ampicillin, ciprofloxacin and cefaperazone–sulbactam. Slime production positive strains were tested against penicillin G, methicillin and bacitracin. No difference was found between the antibiotic resistance of slime positive and slime negative S. aureus. There was a high rate of resistance for all S. aureus isolates against penicillin G, methicillin and bacitracin.  相似文献   

6.
《Food Control》2014,36(1):159-165
This study examined the antimicrobial effect of blueberry (Vaccinium corymbosum L.) extracts obtained from four cultivars (Elliott, Darrow, Bluecrop, and Duke) on the growth of Listeria monocytogenes and Salmonella Enteritidis. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the extracts against L. monocytogenes and S. Enteritidis in tryptic soy broth were determined. Concentrations of total phenolic compounds and four individual phenolic (chlorogenic acid, ellagic acid, quercetin, and quercetin-3-galactoside) in the extracts were determined using Folin-Ciocalteau method and HPLC analysis, respectively. All four extracts at 112.5–900 mg/mL exhibited a dose-dependent growth-inhibitory effect against L. monocytogenes and S. Enteritidis. L. monocytogenes was significantly more sensitive to the antimicrobial effect of the extracts than S. Enteritidis. Phenolic compounds in the extracts such as chlorogenic acid, quercetin, ellagic acid, and quercetin-3-galactoside were the active antimicrobial compounds in the blueberry extracts. The results of this study suggest that blueberry extract or extract-derived components may be used to control pathogenic microorganisms. More studies on the use of blueberry as a natural antimicrobial in food products are warranted.  相似文献   

7.
Staphylococcus aureus (S. aureus) biofilms are of considerable interest in food safety because biofilms can increase the risk of food contamination and enhance the pathogenicity of bacteria. The ica-encoded polysaccharide intercellular adhesin (PIA) plays an important role in biofilm formation. In this study, the MIC of gallic acid against S. aureus in suspension and in biofilms was 2 mg/mL and 4 mg/mL, respectively. Quantitative crystal violet staining of biofilms showed that 2 mg/mL gallic acid can effectively inhibit biofilm formation and the ESEM images clearly showed the three-dimensional biofilm morphology of the S. aureus and the resulting anti-biofilm effect. The determination of viable bacteria in the biofilm revealed that gallic acid penetrated the biofilm to kill S. aureus, the bactericidal effect on the biofilm bacteria was comparable to that of planktonic bacteria. We further explored the influence of gallic acid on ica family gene expression and polysaccharide slime formation in S. aureus biofilm formation. The results showed that icaR was significantly activated that; icaA and icaD were downregulated in a dose-dependent manner with increasing concentrations of gallic acid; however, the expression of icaB and icaC was not significantly affected. The polysaccharide slime formation was reduced as well. Based on these results, gallic acid, as a natural substance, may play an important role in the food industry.  相似文献   

8.
Considering the role of biofilm in food spoilage and the food industry, inhibition of biofilm formation by natural agents is expected to be safe and could also enhance the efficacy of other antimicrobial strategies for controlling microbial food spoilage. Plant flavonoids are known for their diverse biological activity including antimicrobial. Therefore, rutin was investigated for its biofilm inhibitory activity at sub-minimum inhibitory concentrations (sub-MICs) values against common foodborne pathogens (Escherichia coli and Staphylococcus aureus). Minimum inhibitory concentrations (MIC) ranged from 400 to 1600 μg/ml against the selected strains. Sub-MICs (1/16 × MIC to 1/2 × MIC) were used to assess the inhibition of biofilm formed by E. coli and S. aureus in microtitre plate assay. Mono strain biofilm formation by Escherichia coli and Staphylococcus aureus was greatly reduced by rutin at their respective 1/2 × MIC. For multi-species (E. coli: and S. aureus) biofilm formation, the reduction in biofilm production was concentration dependent. No significant bacteria mass reduction was recorded for any sub-MIC. SEM images of biofilm inhibition on steel chips confirmed the reduction in number of microcolonies. Exopolysaccharide production responsible for adherence and maturation of biofilms was also significantly (p ≤ 0.05) reduced at respective concentrations of rutin in tested strains. To the best of our knowledge, this is the first study describing the effect of flavonoid, rutin on multi-species biofilms consisting of S. aureus and E. coli. Findings of the study indicate a potential application of rutin in the prevention of biofilm on industrial equipment and food contact surfaces and prevent food contamination and spoilage.  相似文献   

9.
10.
The aim of this study was to determine the antimicrobial resistance of Escherichia coli and Staphylococcus aureus isolates from food handlers' hands at primary schools in Hulu Langat district, Selangor (Malaysia). Disc diffusion methods were used to examine the antimicrobial resistance of the bacteria by using ten types of antibiotic discs with different concentrations. The results show that the prevalence of S. aureus (65.88–74.12%) was far higher than the prevalence of E. coli (9.41–14.12%). The percentage isolates of E. coli that were resistant to the antibiotics was 85.71% Penicillin and Chloramphenicol, 57.14% Sulfamethoxazole-Trimethoprim, Ampicillin and Trimethoprim, 28.57% Kanamycin and Tetracycline and 14.29% Ciprofloxacin. All of the isolates had shown susceptible to Gentamicin and Nitrofurantoin. For S. aureus, the percentage isolates that were resistant to the antibiotics was 72.30% Ampicillin, 53.38% Penicillin, 4.73% Nitrofurantoin,1.35% Chloramphenicol and Trimethoprim and 0.68% Kanamycin and Tetracycline. None of the isolates had shown resistant to Ciprofloxacin, Sulfamethoxazole-Trimethoprim and Gentamicin. Multidrug resistant Escherichia coli represented a high percentage (85.71%) of the total positive strains revived whereas multidrug resistant S. aureus strains were only 5.41% of the total positive strains. The existence of multidrug resistant bacteria is quite worrying as they may pose serious threat to the patients. Hence, the microbiological quality of food handlers' hands from foodservice operations should be maintained in a good condition to reduce the existence of multidrug resistance bacteria.  相似文献   

11.
The aims of this study were to evaluate the presence of methicillin-resistant Staphylococcus aureus on the hands and anterior nares of food handlers in public hospitals in the city of Salvador, Bahia, in northeastern Brazil and to evaluate the effectiveness of antiseptics for controlling contamination. Swabs from the nose and hands were collected from 140 food handlers in ten public hospitals, and methicillin-resistant S aureus (MRSA) isolates were confirmed by assessing their growth on selective media, coagulase testing and evaluating their antibiotic susceptibilities. Seventy (50.0%) food handlers were colonized with coagulase-positive Staphylococci on their hands and/or nares, and 40 (28.6%) food handlers were colonized with MRSA. The evaluation of susceptibility to the most commonly used anti-MRSA drugs demonstrated that 72.9% of the isolates from the handlers' hands and 82.5% of the isolates from the anterior nares showed resistance to vancomycin. The presence of MRSA was not correlated with the specific job function of the food handlers (p > 0.05). The logistic regression analysis of the antimicrobial activity of antiseptics against MRSA isolates indicated that 2% chlorhexidine had a significantly higher removal rate than those of alcohol gel and 10% PVP-I (iodophor) (p < 0.05); only 2.2% of the MRSA strains were resistant to chlorhexidine.  相似文献   

12.
Staphylococcus aureus was listed as the 2nd common food-borne pathogens, resulting in diseases such as pneumonia, pseudomembranous colitis, pericarditis and even sepsis. A rapid, simple and sensitive detection method is required to monitor food in cases of contamination by S. aureus. Hence, a novel immunochromatographic test strip (ICTS), based on the two-component reaction (i.e. digoxigenin and anti-digoxigenin, quantum dots-conjugated streptavidin and biotin) in test line with QDs as indicator, was developed for the rapid and sensitive detection of S. aureus. Genomic DNA from bacteria lysis by boiling was extracted easily and rapidly with silica-coated magnetic nanoparticles, and a species-specific gene was amplified by PCR using digoxigenin/biotin-labeled primers. The fluorescence of captured QD labels on the test line and control line served as signals was observed by UV light. The sensitivity and specificity of the ICTS were estimated using bacteria spiked food samples (artificially mixed with cell counts (108 CFU/mL for each bacterium) of Escherichia coli, Listeria monocytogenes and Lactobacillus plantarum). The limit of detection for S. aureus was 3 × 100 CFU/mL and 3 × 101 CFU/g in spiked milk powder and meat samples, respectively, which was not affected by those non-S. aureus strains. Our results showed that QDs-based ICTS was promising for rapid and sensitive detection of S. aureus within 2 h. Hence, this protocol might be useful for screening and monitoring the contamination of S. aureus in food products, and helpful for promoting the prevention and control of communicable disease caused by food-borne pathogen.  相似文献   

13.
Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common pathogens causing nosocomial infections worldwide. Animal-associated MRSA hazard has been recently identified, but less information is currently available regarding MRSA in cattle. The aim of this study was to estimate the presence of MRSA in samples of bulk milk, environmental dust, conjunctival and nasal swabs of workers obtained from thirty dairy cow farms. A total of 200 S. aureus strains were identified using phenotypic and molecular approaches. Three other species (Staphylococcus epidermidis, Staphylococcus xylosus and Staphylococcus saprophyticus) were found. In five S. aureus strains isolated from environmental dust and one S. epidermidis strain derived from human samples, mecA gene was detected showing a specific fragment at 527 bp. Moreover, 66 S. aureus strains were distinguished by susceptibility to 15 antimicrobial agents. The highest resistance profile was ascribed to ampicillin, amoxicillin and penicillin G, both in workers and bulk milk samples. Generally, a multiple resistance to 4 up to 10 antibiotics was detected. S. aureus mecA+ strains and S. epidermidis mecA+ strain showed multiple resistance to 13 and 11 antibiotics, respectively. The obtained results suggested that the low number of MRSA strains, probably of human origin, was due to the appropriate hygienic practices adopted by the dairy cow farms.  相似文献   

14.
《Food Control》2013,31(2):393-399
Minimal inhibitory concentrations (MICs) of seven synthetic phenolic compounds, five commonly used as antioxidants (TBHQ, BHA, BHT, propyl gallate and octyl gallate) and two as antimicrobials (propyl 4-hydroxybenzoate and n-heptyl 4-hydroxybenzoate) were assessed against several strains of two Gram-positive (Staphylococcus aureus and Bacillus cereus) and one Gram-negative (Pseudomonas fluorescens) bacteria, by using a standardized microdilution assay (ISO 20776-1, 2006). Octyl gallate was the most effective compound against the three genera/species of bacteria considered simultaneously (with the exception of four strains of B. cereus, which were resistant for this compound) with MIC values (≤100 μg/ml) lower than the concentrations usually used as antioxidants. TBHQ and n-heptyl 4-hydroxybenzoate were also effective in the control of S. aureus at very low concentrations (MIC of 3.1 μg/ml and 12.5 μg/ml, respectively). Propyl 4-hydroxybenzoate was the most inhibitory phenolic compound against all strains of B. cereus and both tested parabens (propyl- and heptyl-) were not effective for P. fluorescens (MIC > 1600 μg/ml). B. cereus was the bacterial genera that showed more intra-species variation, distinguishing two clearly groups of sensitivity among the strains to octyl gallate and n-heptyl 4-hydroxybenzoate (“sensitive” with mean MICs of 42.8 and 4.2 μg/ml, respectively; and “resistant” with MICs >1600 and >800 μg/ml, respectively). According to all that, octyl gallate would be an interesting phenolic compound for the food industry, not only because of its recognized antioxidant properties but also because of their effectivity as antimicrobial against S. aureus, B. cereus and P. fluorescens.  相似文献   

15.
The chemical composition, antibacterial activity and mechanism of essential oil from Cyperus rotundus rhizomes against Staphylococcus aureus were investigated in this study. Results showed that α-cyperone, cyperene and α-selinene were the major components of the essential oil. The essential oil exhibited strong antibacterial activity against S. aureus with the minimum inhibitory concentration (MIC) and minimum bactericide concentration (MBC) were 10 and 20 mg/mL respectively, and the antibacterial effects increased with increasing essential oil concentrations and treatment time. The electric conductivity, cell membrane integrity, NPN uptake, and membrane potential assays demonstrated that essential oil disrupted the membrane integrity of S. aureus. Electron microscope observations further confirmed that essential oil destroyed cell membrane. Moreover, we found that essential oil could induce cells death of S. aureus through apoptosis pathway based on apoptosis analysis. These findings suggested that essential oil mainly exerted antibacterial activity by damaging cell membrane and membrane-mediated apoptosis pathway.  相似文献   

16.
《Food Control》2014,35(2):645-650
As blueberries are rich in phenolic compounds, which possess a demonstrated antimicrobial activity, it may be interesting to further elucidate its real potential and properties. As such, the main goal of this work was to evaluate the potential antimicrobial activity of Vaccinium corymbosum dry fruits and leaves aqueous extracts against several contaminants/pathogenic microorganisms while at the same time assessing the effect of V. corymbosum over lactic acid bacteria.  相似文献   

17.
The antibacterial properties of Se NPs were investigated against four foodborne pathogens (Escherichia coli O157:H7, Staphylococcus aureus, Salmonella, and Listeria monocytogenes). The cytotoxicity of Se NPs was also studied using the Caco-2 cell line. Se NPs at concentrations of 10 μg/mL or higher exhibited dose-dependent antimicrobial properties against S. aureus, but not on the other three pathogens. Se NPs also exhibited various degrees of toxicity on Caco-2 cells after 24 h of exposure. Cellular shrinkage and irregular shapes of treated bacterial cells indicated that the antimicrobial effects of Se NPs are bacteriostatic, not bactericidal. This is the first study to investigate the antimicrobial activity of Se NPs against important foodborne pathogens. The results of this study demonstrate that Se NPs can be used as an antimicrobial agent to inhibit the growth of S. aureus and can be potentially used for food safety applications.  相似文献   

18.
《Food Control》2007,18(3):196-200
Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a risk factor for patients in general population and particularly in immunocompromised patients. As a matter of fact, it can produce serious infections that may then evolve in septicaemia. However, transmission of MRSA from food to people can represent a serious problem only for immunocompromised people. Vancomycin is the elective antimicrobial commonly used in case of MRSA infection, but S. aureus strains with reduced sensibility to vancomycin are emerging worldwide. We isolated 42 strains of S. aureus from 176 samples of raw meat (poultry, pork and beef) during a one-year survey. Each strain was tested against twelve antimicrobial to verify antibiotic resistance. We found no evidence of methicillin-, teicoplanin- or vancomycin-resistance, but a lot of multiresistant microorganisms, i.e. resistant to three or more antibiotics. These results confirm the hypothesis that antibiotics resistance is present not only in nosocomial bacteria, but also in community environments microorganisms.  相似文献   

19.
《Food Control》2006,17(11):929-932
The antibacterial activities of water, ethanol and hexane extracts of five Australian herbs (Backhousia citriodora, Anetholea anisata, Eucalyptus staigerana, Eu. olida and Prostanthera incisa) against seven food-related bacteria (Enterococcus faecalis, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella Enteritidis, Sal. Typhimurium and Staphylococcus aureus) were determined by the microtitre broth microdilution assay. The water extracts of all the herbs displayed no or low antimicrobial activity against all of the bacteria tested with the exception of S. aureus. Relatively high levels of activity (minimum inhibitory concentrations of 125–15.6 μg ml−1) against this pathogen were present in water extracts from all herbs except P. incisa. The ethanol and hexane extracts of all herbs displayed some activity against a number of the bacteria tested, with no one particular herb displaying an obviously higher level or range of activity. Staphylococcus aureus proved to be the most sensitive of the bacteria tested against the solvent extracts with all extracts displaying activity ranging from 125 to 7.8 μg ml−1, while E. coli and L. monocytogenes, on the other hand, proved the least sensitive with only five of 15 herb/extract combinations displaying any activity against these pathogens. The extracts of the Australian native herbs examined in this study have potential for application in foods to increase shelf-life or promote safety.  相似文献   

20.
The main products of Myristica fragrans are the dried seed (nutmeg) and aril (mace), which are used as spices or condiments to flavor foods. In this study, its leaf and different parts of fruit (pericarp, aril, seed-kernel and shell) were compared for their total phenolic content, antioxidant and anti food-borne bacterial capacities. The 80% methanol extracts of aril, seed-kernel and shell shared the highest total phenolic content with shell extract acted as the greatest primary antioxidant, by having the highest ferric reducing antioxidant power (FRAP) activity (EC50 9.7 ± 0.1 μg/mL), β-carotene-bleaching activity (EC50 21.5 ± 2.7 μg/mL) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity (EC50 160.9 ± 13.9 μg/mL), whereas the pericarp extract exhibited highest secondary antioxidant activity as a metal chelator (EC50 75.6 ± 14.4 μg/mL). Only the aril and seed-kernel extracts were found to inhibit the food-borne bacteria with the lowest minimum inhibition concentration of 50 μg/mL, against Staphylococcus aureus (ATCC12600) and Bacillus cereus (ATCC10876). Our findings suggest the possibility of using the aril and seed-kernel extracts as natural food preservative and other parts as a new source of natural antioxidant for food and pharmaceutical industries.  相似文献   

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