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J Acar

Publications and source records attributed to J Acar.

At least 19 recordsLinked to original sources
PubMed2004

Fumaric acid in apple juice: a potential indicator of microbial spoilage of apples used as raw material.

The effects of heat treatment (evaporation and excessive heating), and microbial contamination (Rhizopus stolonifer, Penicillium expansum and Lactobacillus plantarum) as sources of fumaric acid formation in apple juice concentrates were investigated. Fumaric acid formed in apple juice did not exceed 1.0 mg l(-1) during both commercial-scale evaporation and laboratory-scale excessive heat treatment, indicating that malic dehydration is not the primary source of fumaric acid formation. However, R. stolonifer and L. plantarum produced 18.23 +/- 0.82 and 5.39 +/- 0.31 mg l(-1) fumaric acid as determined in the raw juice obtained from contaminated apples after 5 days of incubation. The mean fumaric acid content of apple juice concentrates manufactured in 2000, 2001 and 2002 were determined as 4.9 +/- 1.9, 5.7 +/- 2.8 and 4.1 +/- 2.6 mg l(-1), respectively. The overall results suggest that the primary source of fumaric acid in apple juice concentrate is the use of apples decayed by certain microorganisms capable of producing fumaric acid.

Beverages↗
PubMed2001

Integration of molecular characterization of microorganisms in a global antimicrobial resistance surveillance program.

The SENTRY Antimicrobial Surveillance Program has incorporated molecular strain typing and resistance genotyping as a means of providing additional information that may be useful for understanding pathogenic microorganisms worldwide. Resistance phenotypes of interest include multidrug-resistant pathogens, extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci, and fluoroquinolone-resistant (FQR) strains of gram-negative bacilli and Streptococcus pneumoniae. Clusters of > or =2 isolates within a given resistance profile that are linked temporally and by hospital location are flagged for DNA fingerprinting. Further characterization of organisms with respect to resistance genotype is accomplished with use of polymerase chain reaction and DNA sequencing. This process has been highly successful in identifying clonal spread within clusters of multiresistant pathogens. Between 50% and 90% of MRSA clusters identified by phenotypic screening contained evidence of clonal spread. Among the Enterobacteriaceae, ESBL-producing strains of Escherichia coli and Klebsiella pneumoniae are the most common pathogens causing clusters of infection, and approximately 50% of recognized clusters demonstrate clonal spread. Clusters of Pseudomonas aeruginosa, Acinetobacter species, and Stenotrophomonas maltophilia have been noted with clonal spread among patients with urinary tract, respiratory, and bloodstream infections. Characterization of mutations in the FQR-determining region of phenotypically susceptible isolates of E. coli and S. pneumoniae has identified first-stage mutants among as many as 40% of isolates. The ability to characterize organisms phenotypically and genotypically is extremely powerful and provides unique information that is important in a global antimicrobial surveillance program.

Bacterial Infections↗
PubMed2001

Antimicrobial resistance: an overview.

Increased antimicrobial resistance in bacteria that are important pathogens of humans, and spread of resistance from the closed environment of hospitals into open communities are increasingly perceived as a threat to public health. Any antimicrobial use, whether in humans, animals, plants or food processing technology, could lead to bacterial resistance. Use of antimicrobials in livestock production is suspected to significantly contribute to this phenomenon in species of bacteria which are common to humans and animals. Further research is required into the specific use conditions that govern the selection and dissemination of resistant bacteria. International travel and trade in animals and food increase the risks of antimicrobial resistance world-wide. Countries are considering import restrictions for products deemed a risk to public health. The Office International des Epizooties, a World Trade Organization reference organisation for the Agreement on the Application of Sanitary and Phytosanitary Measures, develops international standards on antimicrobial resistance which, as is the case for national measures, must be based on risk analysis. The scientific background and problems of resistance in human medicine are reviewed. Current knowledge, missing information and actions to be taken are identified.

Animal Husbandry↗
PubMed2001

Antimicrobial resistance: harmonisation of national antimicrobial resistance monitoring and surveillance programmes in animals and in animal-derived food.

A guideline on the harmonisation of national antimicrobial resistance monitoring and surveillance programmes in animals and animal-derived foods has been developed by the Ad hoc Group of experts on antimicrobial resistance of the Office International des Epizooties. The objective of the guideline is to allow the generation of comparable data from various national surveillance and monitoring systems in order to compare the situations in different regions or countries and to consolidate results at the national, regional and international level. Definitions of surveillance and monitoring are provided. National systems should be able to detect the emergence of resistance, and to determine the prevalence of resistant bacteria. The resulting data should be used in the assessment of risks to public health and should contribute to the establishment of a risk management policy. Specific factors identified for harmonisation include the animal species, food commodities, sampling plans, bacterial species, antimicrobials to be tested, laboratory methods, data reporting, database structure and the structure of reports.

Animals↗
PubMed2001

Antimicrobial resistance: standardisation and harmonisation of laboratory methodologies for the detection and quantification of antimicrobial resistance.

The Ad hoc Group of experts on antimicrobial resistance of the Office International des Epizooties has developed a guideline on the standardisation and harmonisation of laboratory methodologies used for the detection and quantification of antimicrobial resistance. The existing methods (disk diffusion [including concentration gradient strips], agar dilution and broth dilution) are reviewed, including a comparison of their advantages and disadvantages. The definitions of resistance characteristics of bacteria (susceptible, intermediate and resistant) are addressed and the criteria for the establishment of breakpoints are discussed. Due consideration has to be given to these aspects in the interpretation and comparison of resistance monitoring or surveillance data. The use of validated laboratory methods and the establishment of quality assurance (internal and external) for microbiological laboratory work and the reporting of quantitative test results is recommended. Equivalence of different methods and laboratory test results is also recommended to be established by external proficiency testing, which should be achieved by the means of a reference laboratory system. This approach allows the comparison of test results obtained using different methods generated by laboratories in different countries.

Animals↗
PubMed2001

Antimicrobial resistance: monitoring the quantities of antimicrobials used in animal husbandry.

This guideline, developed by the Office International des Epizooties for the monitoring of the quantities of antimicrobials used in animal husbandry, provides the methodology required to assess the amounts of antimicrobials used, to supply data to be used for risk analysis and to improve guidance on the appropriate use of antimicrobials. Information may be gathered from a number of sources, such as the competent authorities, industry and users. The usefulness of different types of information is discussed and recommendations are given on how to collect detailed information, each year, on the antimicrobial quantities used per class and active substance. Information should also be collected on the route of administration (oral and parenteral) and the animal species.

Animal Husbandry↗
PubMed2001

Antimicrobial resistance: responsible and prudent use of antimicrobial agents in veterinary medicine.

A guideline on the responsible and prudent use of antimicrobials in animal husbandry has been developed by the Ad hoc Group of experts on antimicrobial resistance, created by the Office International des Epizooties. The objectives of responsible use are to maintain antibiotic efficacy, to avoid the dissemination of resistant bacteria or resistance determinants and to avoid the exposure of humans to resistance through food. The guideline attributes a central role to the competent authorities responsible for granting marketing authorizations for antimicrobial substances. Requirements before and after granting of marketing authorizations are defined. Important aspects include the control of the pharmaceutical product quality and the therapeutic efficacy, the assessment of the selection pressure, the protection of the environment, specific and non-specific antimicrobial resistance surveillance. The guideline is also addressed to the veterinary pharmaceutical industry, veterinary practitioners, dispensing pharmacists and farmers. The respective roles and responsibilities of these groups are defined.

Animal Husbandry↗
PubMed2001

Antimicrobial resistance: risk analysis methodology for the potential impact on public health of antimicrobial resistant bacteria of animal origin.

The Ad hoc Group of experts on antimicrobial resistance, appointed by the Office International des Epizooties, has developed an objective, transparent and defensible risk analysis process, providing a valid basis for risk management decisions in respect to antimicrobial resistance. The components of risk analysis and of different possible approaches in risk assessment (qualitative, semiquantitative and quantitative) are defined. The Ad hoc Group recommended the following: an independent risk assessment based on scientific data; an iterative risk analysis process; a qualitative risk assessment systematically undertaken before considering a quantitative approach; the establishment of a risk assessment policy; and the availability of technical assistance for developing countries.

Animals↗
PubMed2000

[When is surgery needed for minimally symptomatic or asymptomatic acquired valvulopathy?].

GENERAL PRINCIPLES: The first step is to determine the absence or the minimal nature of the functional impairment from history taking and, for doubtful cases, with an exercise test. Therapeutic indications differ depending on the valvular lesion. AORTIC STENOSIS: Surgery is indicated only for severe aortic stenosis or in cases with a particular risk. Indications for surgery are: false asymptomatic patients with a positive exercise test, patients with abnormal hemodynamic and/or rhythm response to an exercise test (decrease in systolic pressure > 10 mmHg, severe ventricular arrhythmia), aortic stenosis with left ventricular ejection fraction < 50%, aortic stenosis associated with severe coronary artery disease amendable with bypass surgery. MITRAL STENOSIS: The advent of percutaneous mitral commissurotomy has totally changed the treatment of mitral stenosis. This new method can be proposed for stenotic but flexible mitral valves with no major lesion of the lower valvular apparatus or for more advanced valve disease with a risk of hemodynamic failure or thromboembolism. MITRAL INSUFFICIENCY: When mitral leakage is the only valvular defect, surgery is indicated if the volume regurgitated is important as assessed clinically and by echocardiography. Conservative surgery is preferred due to the low risk and the high probability of good long term outcome. Factors to take into account include: the experience of the surgical team in this field, the etiology of mitral insufficiency, the impact on the cardiac condition. Surgery should be performed before the development of atrial fibrillation, major cardiomegaly, left ventricular dilatation (end systolic diameter > 45 mm), or an alteration of the ejection fraction (< 60%). AORTIC INSUFFICIENCY: Cases of the aortic insufficiency should be differentiated according to the state of the ascending aorta. Annuloaortic ectasia requires surgery when the diameter reaches = 50-55 mm (depending on the authors). For valve dysplasia with non aneurysmal cylindrical dilatation of the ascending aorta, the indication for surgery depends on the progressive aggravation of the aortic dilatation. For cases with unique valve lesions, the indication for surgical repair of aortic insufficiency depends on the impact on the left ventricle. Indications for surgery include major radiographic cardiomegaly (cardio-thoracic ratio > 0.58), echocardiographic evidence of major left ventricular dilatation (end diastolic diameter > 75 mm and end systolic diameter > 55 mm), or an alteration of the systolic function (ejection fraction < 0.50 or 0.55). SPECIAL SITUATIONS: In disease states associating stenosis and insufficiency, valve replacement is often the only possibility. Careful patient selection is the rule. Surgery is often needed for cases with multiple valve involvement where different therapeutic options can be used for the different valves. The dominant lesion and the degree of heart dilatation and dysfunction guide decision making.

Age Factors↗
PubMed2000

Enzymatically validated liquid chromatographic method for the determination of ascorbic and dehydroascorbic acids in fruit and vegetables.

A liquid chromatographic method has been described for the determination of total vitamin C, ascorbic acid (AA) and dehydroascorbic acid (DHAA) in fruits and vegetables. The complete separation of AA and DHAA could be achieved on a C18 column using 0.2 M KH2PO4 (pH adjusted to 2.4 with H3PO4) as the mobile phase at a flow-rate of 0.5 ml/min. Since the detection sensitivity was poor for DHAA even at 210 nm, it was estimated as the difference between the total AA after DHAA reduction and AA content of the original sample, using dithiothreitol (DTT) as the precolumn reductant. The reaction times for the complete conversion of DHAA to AA at room temperatures were 150, 120, 90 and 75 min for 1, 2, 4 and 8 mmol DTT per mmol of DHAA, respectively. The percentage recovery ranged from 81.7 to 105.9. AA contents of some selected fruits and vegetables were analyzed comparatively by liquid chromatography and enzymatic assay to validate the method.

Ascorbic Acid↗
PubMed2000

Antimicrobial resistance among urinary tract infection (UTI) isolates in Europe: results from the SENTRY Antimicrobial Surveillance Program 1997.

The SENTRY Antimicrobial Surveillance Program was established to monitor the occurrence and antimicrobial susceptibility of bacterial pathogens via an international network of sentinel hospitals. Twenty European hospitals referred a total of 887 urinary tract infection (UTI) isolates to the European SENTRY reference laboratory during the period October-December 1997. Ninety percent of the referred species were represented by Escherichia coli (52%), Enterococcus spp. (12%), Klebsiella spp. (7%), Proteus spp. (7%), Pseudomonas aeruginosa (7%), and Enterobacter spp. (5%). The susceptibility of E. coli isolates to penicillins was less than 60%, while almost all of the isolates were susceptible to piperacillin/tazobactam (98% susceptibility), cephalosporins (98%), and carbapenems (100%). Amikacin was the best aminoglycoside (99.8% susceptibility). The susceptibility to quinolones was only 88-89%, with highest levels of resistance observed for isolates from Portugal, Italy, England, The Netherlands, and some centers in France, Spain, and Poland. The susceptibility of Klebsiella spp. to the newer generations of cephalosporins was 82-95% and to the carbapenems 100%. Amikacin was again the best aminoglycoside (94% susceptibility). The susceptibility of Enterobacter spp. to any beta-lactam antibiotic was poor, except for the carbapenems (100% susceptibility) and cefepime (90% susceptibility), while the susceptibility to aminoglycosides was 80-89%. Proteus spp. showed complete susceptibility to cefepime, ceftriaxone, the carbapenems, and piperacillin/tazobactam, while the susceptibility of P. aeruginosa isolates was poor, with best results for the carbapenems (susceptibility 89%), piperacillin/tazobactam (susceptibility 84%), and amikacin and ticarcillin (susceptibility to both 80%). Enterococcus spp. showed the highest susceptibility to vancomycin (98%), teicoplanin (98%), and ampicillin (94%).

Candida↗
PubMed2000

Antibiotic resistance in nosocomial pulmonary pathogens.

Nosocomial pneumonia is the second most common hospital-acquired infection and are associated with antibiotic-resistant microorganisms. In nosocomial pneumonia, both the diagnosis of the disease and the identification of the pathogen agent are controversial. The lack of standard diagnostic criteria can lead to the inappropriate use of broad-spectrum antibiotic therapy and the emergence of multiresistant bacteria. Moreover, empirical antibiotic treatment must be prescribed after bacteriological sample but before culture results because the majority of nosocomial pneumonias require an urgent antibiotic therapy. Most nosocomial pneumonias are of an endogenous origin, particularly in mechanically ventilated patients, and this is associated with a higher rate of multiresistant methicillin-resistant Staphylococcus aureus, Acinetobacter baumanii, Klebsiella pneumoniae with extended spectrum b-lactamases, and Pseudomonadaceae. Multiple factors influence the frequency of pathogens associated with antibiotic resistance, such as duration of hospital stay, time of onset, prior antibiotic therapy, and local microbial ecology.

Journal Article↗
PubMed2000

Long-term survey of patulin in apple juice concentrates produced in Turkey.

A liquid chromatographic method described by us elsewhere was evaluated for a long-term survey of patulin in apple juice concentrates. Patulin was separated on a reversed phase C18 LC column with water-acetonitrile (99:1) as the mobile phase and quantitated with a photodiode array (PDA) detector. Relatively low amounts of patulin (< 5 micrograms/l for single strength juice at 11.2 degrees Bx) were detected in apple juice concentrates and confirmed by PDA detector, comparing the corresponding UV spectra with that of patulin standard. Four hundred and eighty two apple juice concentrates produced through 1996-99 were analysed for their patulin contents. Year-to-year variations in patulin levels of apple juice concentrates were found out to be statistically significant. Patulin contamination levels of apple juice concentrates tended to decrease through the years and averaged 63, 43, 19 and 31 micrograms/l in 1996, 1997, 1998 and 1999, respectively. Percentages of concentrates exceeding the maximum permitted concentration of 50 micrograms/l were 52%, 34%, 8% and 8% for 1996, 1997, 1998 and 1999, respectively.

Beverages↗
PubMed2000

Antimicrobial susceptibility and frequency of occurrence of clinical blood isolates in Europe from the SENTRY antimicrobial surveillance program, 1997 and 1998.

As part of the European arm of the SENTRY Antimicrobial Surveillance Program, 25 European university hospitals referred 9613 blood isolates for in vitro testing against >20 antimicrobial agents. Escherichia coli, Staphylococcus aureus, coagulase-negative Staphylococcus, Pseudomonas aeruginosa, and Klebsiella pneumoniae were the 5 most frequent isolates and accounted for two-thirds of all referrals, with minor regional variation. Of these, approximately 0.36% of E. coli and 16.7% of K. pneumoniae isolates proved to be potential extended-spectrum beta-lactamase producers, and their incidence clearly varied regionally. Quinolone resistance was detected among gram-negative species; in particular, P. aeruginosa and Acinetobacter species. Considerable regional variation was observed in the incidences of methicillin resistance in S. aureus and penicillin resistance in Streptococcus pneumoniae. The incidence of vancomycin resistance in enterococci was relatively low overall and primarily associated with Enterococcus faecium. However, extrapolation of these data to smaller and nonteaching hospitals should be undertaken with caution, since resistance rates may be lower in these facilities.

Anti-Bacterial Agents↗
PubMed1999

Simultaneous determination of 5-hydroxymethylfurfural and patulin in apple juice by reversed-phase liquid chromatography.

A rapid, simple and economical method was described for the simultaneous determination of 5-hydroxymethylfurfural (HMF) and patulin in apple juice. The sample was extracted with ethyl acetate and the extract was then cleaned up by extraction with a sodium carbonate solution. Then HMF and patulin were determined by reversed-phase liquid chromatography using a C18 column and a photodiode array detector. HMF and patulin could be completely resolved by using the mixture water-acetonitrile (99:1, v/v) as the mobile phase with a flow rate of 1.0 ml/min. Mean recoveries of HMF ranged from 86% to 100% with an overall mean of 94%, that of patulin ranged from 94% to 125% with an overall mean of 103%, for different spiking levels. The limits of detection for HMF and patulin in apple juice were found to be < 0.01 mg/l and < 5 micrograms/l, respectively.

Beverages↗
PubMed1999

Frequency of occurrence and antimicrobial susceptibility of bacterial pathogens associated with skin and soft tissue infections during 1997 from an International Surveillance Programme. SENTRY Participants Group.

The SENTRY Antimicrobial Surveillance Programme was established to provide a coordinated, standardised, international surveillance on antimicrobial resistance. In one part of the programme, isolates from skin and soft tissue infections sent from 20 hospitals in 12 different European countries were investigated in the European coordinating centre. Of 1013 isolates, Staphylococcus aureus and Pseudomonas aeruginosa were the most significant species, constituting almost 50% of the referred isolates. Methicillin resistance in Staphylococcus aureus averaged 22% across Europe, only slightly less than that in isolates derived from blood. Less than 5% of the enterococcal isolates were resistant to vancomycin. Piperacillin/tazobactam was the most active penicillin-derived beta-lactam compound against Pseudomonas aeruginosa, inhibiting 91.3% of the isolates, while ceftazidime and cefepime were the most active cephalosporins, inhibiting 85.8% and 80.3% of the isolates, respectively. Putative extended-spectrum beta-lactamase production was not detected in Escherichia coli and was found in only 5.1% of the Klebsiella pneumoniae isolates. In general, strains of the family Enterobacteriaceae remained mostly susceptible to carbapenems, cefepime, and amikacin.

Anti-Bacterial Agents↗
PubMed1999

Antimicrobial resistance among community-acquired pneumonia isolates in Europe: first results from the SENTRY antimicrobial surveillance program 1997. SENTRY Participants Group.

OBJECTIVE: The SENTRY antimicrobial surveillance program was established to monitor the occurrence and antimicrobial susceptibility of bacterial pathogens via an international network of sentinel hospitals. MATERIAL AND METHODS: Microorganisms were forwarded to the reference laboratory for testing against various antimicrobial agents using broth microdilution. Twenty European hospitals referred 286 Streptococcus pneumoniae, 309 Haemophilus influenzae, and 167 Moraxella catarrhalis isolates during the first 10 months of the study, starting in April 1997. RESULTS: Seven percent of the S. pneumoniae isolates were highly resistant to penicillin, and 21% showed intermediate resistance. The highly resistant pneumococcal isolates came from Coimbra, Barcelona, Athens, and London, whereas the intermediate penicillin-resistant isolates were received from all participating countries. The incidence of intermediate penicillin-resistant pneumococci was lowest in Lausanne, Freiburg and Duesseldorf, London, and Utrecht and highest in southern European countries. Fifty-five percent of the penicillin-resistant S. pneumoniae were also resistant to erythromycin, and 35% to clindamycin. Sparfloxacin, trovafloxacin, levofloxacin, and vancomycin were fully active against pneumococcal isolates. Haemophilus influenzae isolates were generally highly susceptible to most of the antibiotics tested, and 92% of the M. catarrhalis isolates were resistant to penicillin. Susceptibility to cephalosporins, ciprofloxacin, levofloxacin, and rifampicin was 100%. CONCLUSION: Penicillin may no longer be the first-choice drug for empirical treatment of pneumococcal infections. The newer fluoroquinolones may play a role in the empirical treatment of community-acquired pneumonia.

Anti-Bacterial Agents↗